. HUG. 100-461 PT. 2

GREENHOUSE EFFECT AND GLOBALCLIMATE CHANGE

HEARINGBEFORE THE

COMMITTEE ONENERGY AND NATURAL RESOURCES

UNITED STATES SENATEONE HUNDREDTH CONGRESS

FIRST SESSION

ON THE

GREENHOUSE EFFECT AND GLOBAL CLIMATE CHANGE

JUNE 23, 1988

PART 2

Printed for the use of theCommittee on Energy and Natural Resources

89-339

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON : 1988

For sale by Qie Superintendent of Documents, Congressional Sales Office

U.S. Government Printing Office, Washington, DC 20402

.5 61 7 -

COMMITTEE ON ENERGY AND NATURAL RESOURCES

J. BENNETT JOHNSTON, Louisiana, ChairmanDALE BUMPERS, ArkansasWENDELL H. FORD, KentuckyHOWARD M. METZENBAUM, OhioJOHN MELCHER, MontanaBILL BRADLEY, New JerseyJEFF BINGAMAN, New MexicoTIMOTHY E. WIRTH, ColoradoWYCHE FOWLER, JR., GeorgiaKENT CONRAD, North Dakota

JAMES A. McCLURE, IdahoMARK 0. HATFIELD, OregonLOWELL P. WEICKER, JR., ConnecticutPETE V. DOMENICI, New MexicoMALCOLM WALLOP, WyomingFRANK H. MURKOWSKI, Alaska -DON NICKLES, OklahomaCHIC HECHT, NevadaDANIEL J. EVANS, Washington

DARYL H. OWEN, Staff DirectorD. MICHAEL HARVEY, Chief Counsel

FRANK M. CUSHING, Staff, Director for the MinorityGARY G. ELLSWORTH, Chief Counsel for the Minority

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CONTENTS

STATEMENTSPage

Baucus, Hon. M ax, U.S. Senator from M ontana ........................................................ 31Bumpers, Hon. Dale, U.S. Senator from Arkansas ................................................... 38Chafee, Hon. John H., U.S. Senator from Rhode Island .................... 99Conrad, Hon. Kent, U.S. Senator from North Dakota .............................................. 31Dudek, Dr. Daniel J., senior economist, Environmental Defense Fund ................ 117Hansen, Dr. James, Director, NASA Goddard Institute for Space Studies .......... 39Johnston, Hon. J. Bennett, U.S. Senator from Louisiana ................... 1Manabe, Dr. Syukuro, Geophysical Fluid Dynamics Laboratory, National

Oceanic and Atmospheric Adm inistration .............................................................. 105Moomaw, Dr. William R., director, Climate, Energy and Pollution Program,

W orld R esources Institute .......................................................................................... 142Murkowski, Hon. Frank H., U.S. Senator from Alaska .................... 104Oppenheimer, Dr. Michael, senior scientist, Environmental Defense Fund ........ 80Wirth, Hon. Timothy E., U.S. Senator from Colorado ............................................. 5Woodwell, Dr. George M., director, Woods Hole Research Center ......................... 91

APPENDIXES

APPENDIX I

Responses to additional questions ................................................................................. 161

APPENDIX IIAdditional material submitted for the record .......................... 188

(III)

GREENHOUSE EFFECT AND GLOBAL CLIMATECHANGE

THURSDAY, JUNE 23, 1988

U.S. SENATE,COMMITTEE ON ENERGY AND NATURAL RESOURCES,

Washington, DC.The committee met, pursuant to notice, at 2:10 p.m., in room SD-

366, Dirksen Senate Office Building, Hon. J. Bennett Johnston,chairman, presiding.

OPENING STATEMENT OF HON. J. BENNETT JOHNSTON, U.S.SENATOR FROM LOUISIANA

The CHAIRMAN. The hearing will come to order.Last November, we had introductory hearings on the question of

global warming and the greenhouse effect. We listened with mix-tures of disbelief and concern as Dr. Manabe told us that the ex-pected result of the greenhouse effect was going to be a drying ofthe southeast and midwest. Today as we experience 1010 tempera-tures in Washington, _DCand the soil moisture across the midwestis ruining the soybean crops, the corn crops, -thecotfion -crops,- whepwe're having emergency meetings of the Members of the Congresin order to figure out how to deal with this emergency, then thewords of Dr. Manabe and other witnesses who told us about thegreenhouse effect are becoming not just concern, but alarm.

We have only one planet. If we screw it up, we have no place elseto go. The possibility, indeed, the fact of our mistreating this planetby burning too much fossil fuels and putting too much CO2 in theatmosphere and thereby causing this greenhouse effect is now amajor concern of Members of the Congress and of people every-where in this country.

The question is what do you do about it. Well, the first thing youdo about it is learn about it, what is happening, why is it happen-ing, how serious is the problem. Then we must begin to addressthis very serious problem. The leader in this problem on this com-mittee has been Senator Tim Wirth from Colorado. Working withhim, we have included some $3 million in the energy and water ap-propriation bill to begin our studies, and it is in this committeewhere the lead investigations and hearings will be held.

It is safe to say that this problem is not going to go away. It isnot like a stock market crash which corrects itself in a matter ofweeks or months. The problem is going to only get worse. It is notgoing to be easily correctable, and once we begin to find the solu-tions, we know those solutions are going to be both expensive as we

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2

find alternate fuels and are going to involve massive internationalefforts.

So, as we begin today, we are doing so with a consciousness thatthis is not some esoteric study of little interest to the ordinary citi-zen of the United States. This is not some economic study on some-body's theory. The greenhouse effect has ripened beyond theorynow. We know it is fact. What we don't know is how quickly it willcome upon us as an emergency fact, how quickly it will ripen fromjust simply a matter of deep concern to a matter of severe emer-gency. And what we don't know about it is how we're going to dealwith it and how we're going to get the American people to under-stand that perhaps this drought which we have today is not just anaccidental drought, not just the kind of periodic drought which wehave from time to time but is, in fact, the result of what man isdoing to this planet.

So, with that, I would like to turn the Chair over to SenatorWirth who will be chairing these hearings and leading our commit-tee on the subject of global warming. And I turn the Chair over tohim with our thanks for his leadership in this area.

[The prepared statement of Senator Johnston follows:]

STATEMENT OF THE HONORABLE J. BENNETT JOHNSTON

JUNE 23, 1988

I am pleased to welcome you to this afternoon's hearing on the

Greenhouse Effect and policies for controlling global climate change.

Testimony presented last November, in hearings befor tHi6

Committee, contained sobering predictions regarding the degree and pace

of global warming. Today's Greenhouse hearings will elaborate on two

particularly striking facts; the first is the rapidity with which the

problem of global climate chazqe is entering the public and politic" ...,_,,.

consciousness; and the second is the dramatic decrease in projected

time before the effects of climate change, sea level rise, and habitat

degradation begin to be felt.

The current drought situation teaches us how important climate is

to the nation's social, economic, and physical well being. The United

States is currently mobilizing its political and financial resources to

grapple with the enormous agricultural devastation of the present dry

spell over the midwest and southeast portions of the United States.

The present drought graphically illustrates only a small portion of the

scenario which could transpire if global warming and climate change

predictions are accurate.

Taking the proper steps to control the degree and pace of global

warming will not be easy. The policy choices that will need to be made

involve critical political and economic decisions. These hearings

4

should spur us to once again examine the strong links between energy

policy and the greenhouse effect. The burning of fossil fuels is a

major contributor to the greenhouse effect. However, no one believes

that we can end our dependence on these fuels overnight.

Nevertheless, the United States must make a concerted effort to

increase its use of energy sources that emit relatively less qarbon

dioxide and other trace gases. We must revive our nuclear industry by

developing a new generation of passively safe, economical nuclear

reactors. We must push even harder to adopt commercially available

energy efficiency measures and we must generously'-fund more research

and development efforts in this area. We must also proceed with

research that can lead to cost breakthroughs in fusion, solar, and

other renewable energy sources.

We must remember also, that the greenhouse effect is implicitly

linked to resource and environmental policy. The Montreal Protocol 0

CFC emissions is an encouraging sign that we are working in the right

direction -- we must take all possible measures to ensure that this

unprecedented agreement is a success. Steps are already underway in

:the Senate to encourage the United State to work toward strengthening

the Protocol's phase-out of chlorofluorocarbons. Some have called for

a similar Protocol to address the potentially more serious issue of

global climate change and warming. However, it is clear that an

internatio I agreement to r ontrol C02 and trace gas emissions will be

even more problematic.

I am looking forward to today's hearings to provide some insight

into the formidable task the Committee and, in fact, the nation, must

face. I hope to use today's testimony as a focus for the discussion of

a Congressional agenda that addresses near-term global change policy

options.

5

STATEMENT OF HON. TIMOTHY E. WIRTH, U.S. SENATOR FROMCOLORADO

Senator WIRTH [presiding]. Thank you very much. We greatly ap-preciate your farsighted direction of the committee dating back along way when we first began to think about this, the hearingsthat were held, and also your great help in assisting in gettingfunding in this current appropriations cycle that I think will do alot to not only help the research that is going on, the collection ofthe data that has to be done, the standardization of that data, andbeginning to get that information out to a variety of communitiesin the country. We thank you very much for giving me this oppor-tunity.

In the last week many of us have been seeing firsthand the ef-fects of the drought that is occurring across the heart of The coun-try. Meteorologists are already recording this as the worst droughtwe have experienced since the Dust Bowl days of the 1930's. Themost productive soils and some of the mightiest rivers on earth areliterally drying up. Let me cite just a few examples. Already morethan 50 percent of the northern plains' wheat, barley and oatshave been destroyed, and the situation could get much worse. OnTuesday, the Mississippi River sank to its lowest point since atleast 1872 when the U.S. Navy first began measurements. And inmy home State of Colorado, peak flows are among the lowest onrecord, and reservoir levels are also alarmingly low.

We must begin to ask is this a harbinger of things to come. Isthis the first greenhouse stamp to leave its impression on our frag-ile global environment? I understand that Dr. Hansen will providetestimony this afternoon that points clearly in that direction.

The scientific community has done an outstanding job of compil-ing and analyzing mountains of evidence about global climatechange. As I read it, the scientific evidence is compelling. Theglobal climate is changing as the earth's atmosphere gets warmer.Now the Congress must begin to consider how we are going to slowor halt that warming trend, and how we're going to cope with thechanges that may already be inevitable.

In essence, this is an issue that has moved from the world of sci-'ence to the policy arena in the United States, and throughout theworld. All of us must begin to face up to the fact that if we contin-ue emitting vast quantities of the greenhouse gases, we're going toface a global temperature rise larger than anything experienced inhuman history.

The purpose of today's hearings is to examine more closely theprospects of a warmer world and the implications of such a worldfor public policy. And as the drought conditions have clearly dem-onstrated, those considerations stretch across the public policyspectrum. The Energy Committee must move aggressively to exam-ine how energy policy has contributed to the greenhouse effect andthe kinds of changes in energy policy that may be needed to re-verse the trend of increased emissions of carbon dioxide, a key by-product of the burning of fossil fuels.

6

I hope that today's outstanding witnesses will join the committeein this process, and I know that we can count on your counsel inthe future. Today we have some of the finest researchers on theissue of climatic change, but before introducing them, let me askmy colleagues if they have Opening remarks that they might like tomake.

[The prepared statement of Senator Wirth follows:]

7

Senator Tii W irth.NFIS RELEASE

U.S. Sena ic Washington, D.C. • 20510 FOR RELASE:

'nURDAL JUNE S22g. 1988(202) 224-5852

STATEMENT OF THE HONORABLE TIMOTHY E. WIRTH

JUNE 23, 1988

I want to begin by thanking the Chairman of the Energy and

Natural Resources Committee, Senator Johnston, for his leadership on the

issue before the Committee today, global warming and the so-called

"greenhouse effect." Senator Johnston's assistance in convening this

hearing, and the two days of hearings I chaired last fall, has been

instrumental in focusing this Committee's attention on these profoundly

important issues. I also would like to welcome Senator Chafee and

Senator Baucus, who have consistently demonstrated their leadership in

the effort to protect the global environment.

In the past week, many of us have been seeing first-hand the

effects of the drought that. is occurring across the heart of this

country. Meterologists already are recoding this as the worst drought

this nation has experienced since the Dust Bowl days of the 1930s. The

most productive soils and some of the mightiest rivers on earth are

literally drying up. Let me just cite several examples. Already, more

than 50 per cent of the Northern Plains' wheat, barley, and oats have

been destroyed and the situation could get much worse. On Tuesday, the

Mississippi River sank to its lowest point since at least 1872, when tht

U.S. Navy first began measurements. And in my home state of Colorado,

peak flows ore among the lowest on record and reservoir levels are

alarmingly low.

MORE

8

We must begin to ask: is this a harbinger of things to come? Is

this the first greenhouse stamp to leave its impression on our fragile

global environment? I understand that Dr. Hansen will provide testimony

today that points clearly in that direction.

The scientific community has done an outstanding job of compiling

and analyzing mountains of evidence about global climate change. As I

read it, the scientific evidence is compelling: the global climate is

changing as the Earth's atmosphere gets warmer. Now, the Congress must

begin to consider how we are going to slow or halt that warming trend,

and how we are going to cope with the changes that may already be

inevitable.

In essence, this is an issue that has moved from the world of

science to the policy arena. All of us must begin to face up to the

fact that if we continue emitting vast quantities of the greenhouse

gases, we are going to face a global temperature rise larger than

anything experienced in human history.

The purpose of today's hearing is to examine more closely the

prospects of a warmer world and the implications of such a world for

public policy. And as the drought conditions have clearly demonstrated,

those considerations stretch across the public policy spectrum. The ",

Energy Committee must move aggressively to examine how energy policy has

contributed to the the greenhouse effect, and the kinds of changes in

energy policy that may be needed.to reverse the trend of increased

emissions of carbon dioxide, a by product to the burning of fossil

fuels, and 50 percent of the greenhouse problem.

9

PAE TREE

I hope that today's outstanding witnesses will join the committee

in this process and that we can count on their counsel again in the

future. Today, we have with us some of the nation's finest researchers

on the issue of climatic change. Michael Oppenheimer, Senior Scientist

at the Environmental Defense Fund and George Wooduell, Director of the

Wood's Hole Research Institute, two of the three Amer!can participants

and major contributors to the report we are examining today from the

Beijer Institute.

James Hansen, Director of the Goddard Institute for Space

Studies, whose climate data have shown that four of the warmest years on

record have occurred during this decade. Dr. Syukuro Manabe from the

National Oceanic and Atmospheric Administration and Daniel Dudek of the

Environmental Defense Fund, both of whom have done extensive work on the

implications of climate change for agricultural patterns. And Bill

Moomaw of the World Resources Institute, who has done extensive work on

the public policy responses that should be considered to address this

problem. We thank you all for coming.

N N N

10

11

.AIo1 , the newi for iuly 4. 2030* The second t lI icade oft/ie year hajt, ti/cl the Fjvt Coast 17te 15-oo sea-

wol huh to piotet BBaltimlore. Phila-

,d'lphia. New VOtA atd Boston held4.tilUln 12-foot tides, hut a 25-foottoi n ,ige swept over the eastern tip o1

ton Itland. drowning 260 residentsiho haid tefsed to leave their homes

ihtlitt- ti ,iloil ei'actiontll order Tireto/i of dead on Afa/rth Vitieyard.'itimci t td Cope Cod is estimated

atSO T/ii Ji0fatalhites are still furfew-ethit sihe 5.600 people who drowited titI it mouth t lint i iatne itl south Florida* T euti'ito inches of rain front the

Iiiii tlne lOOled Washigton. DC.let A'i the heat %ae that had

,.tetplid the city for 62 straight days of90.plii stepetuttes This fell short oftile itcoid lit eight reats ago whens 72coilleiiitive 90.plus days caused thetlOi 9* of the italtin cs apital to the coolerenllott of ?latqlitette. Afich* In epulhedu. Calif. neighbors ham-meted (ilt eihti/ Kidow to death %hen

I/l, healleld t ie had been secretly wa-tetlilA' 0 pot o Ket atit Pts A fotnote to

thit grlni, stop s The .oman's husbandhad ihed of tihirst dimtti the Californiadi ought of ; 998o /'Fnl riots i,.o e out in France. whet eIiIC ti l/i, ot11 h'tii f i titttlid hio , tt tiled

itll i 1 lli1d lilt' P tiwlll I t p t" lilll i'

0 [)io it hot / ( oIlld llllllltie Iti tie

Plaint ti ll I/l' I. S 1 /tit Otih't"ititllt om t1 lip Ill ,italI(hetaitl Ilo

dwtelo . Jhft14 the ololov)A 101 1 '+I d

* Ill Sr1ovi, Iv t bottlnists attiOll cd

thv 'lh of the li it t ed spruce The spe-clie% dttill e t% lttd i t a cottlitilla

i1011 of i li'i acid ftm" globtill A lltl 1 de, / iIt iler /t litdlillt

a Is huiehiil the 4ichotage ravi

beat the .e)% oi k ifets 5 3 /I Los

4'..,eiei. Ih l)tolet gattie ai'ainst theC51al,s Gtmi elar scheduled fin tit; usual

S30 it n1 tI ill poitpoted becauseofthist t011111t 4'd t11i ll,, tarllt ..et'ret leasing aith i'deti tictlion il its/tke' alongtheI it Coitt Iltimicane Bruce is e-

peted to ttli e ) to sea dt uiting the

mhr Ill tht %hieIt, Sot/htest and

14 'tit cottdittill temttitl 'tilal sear-

,tug hear thoiit (told dangetois levelsofl t avltvet tmdiatioti

Ri*ORDI, 1 PRI VIOL S (I IMA|I(" CIIA\GIS SUGGISr IIIAi I VI \ I\Il I

U t 111 IISKIt',IIKI \ ',WAS ASI

horl Satllmlit

il \10'iit I it-' it

isi I this rej st has been ,\-ta, 1tilatcd Ci illl ,:1refull% ..onsldercd forecast. f(o our plan-et by a "I& arle> ofSlen-

IIstsas %AC ",pil toiard ihe 21st c ntUlIPollutants are saturatlng our atlll

sphere AIld rain. \huch aiead% hashad a desastatlig Illltt1 oil prts ofeastern North America central 1 u-rope and oulhern Siandtna-.ia is onemttanuifestation of this 1ittllutitn but i't

clTe'ts tend it he regional Tlo smiila

and interrelated pillutant thrtats lt iii

e\sen larger, and the\ ma% soon tff tilife on a global scale lth ha\e thepotential of breaking ,atastrophit.change on the earth s cinate .tnd

on life

The first of (he'e thge.tls is thellulion caused b the rclease of . hhorollu

or'.'atons into the atliIphCle T hese

mn-lm-t+tade chemli.al collpojt ldsmole coiionl called ( F( s ar

used as refrtigerattrs and ci.iltis and

in the manufacture of eerthl',g (fom

pillhtws to poly:y:rere twttes fot fastfoW Eer since their It~eilltito not

quite 60 )eats ago (UCs ha\e beenrising into the slratophere \hen thehit the protects\ comer kittl n ats theotllle la t - IO to 20 iiles up- theN

raist hell because their chlorine coi-

potnent devours the molecules thatform the thin t/one shell As that layeris depleted. stronger and strongerdt¢s of ultr,.|iolet IUVI raditllton

from the sun are able it) penetrate itthe earth's surface Skin diseases atid

so

12

liI',t t\ (it t1lt1t I! MPI RAIWRI'i ('0) II) If \V1 I iil(Itll ', Ill P i I1 'NiVl\

Ip lani des.li-1 ll11011 .IlV 011.\ file' I .gili'lie f iriihtoubl sthaie C\i'rls e tLAieti

iraduiion :aii cause

t he tither major threat i\ xiui td listhe t.utltirtuilig buildup , tof lr'itin dioii-ide nitri's uisgdc and trajc g ses il-, tlding Il ( s ii the atiorisphere Iinthe 150 lit A) >ears sln{e the industr lit1t'ltlt0n mani s cti Iles hase Cmrii-iiuuu'iIs increased the atm sphertl'illcetrati tons of these gas The rap-idlt espindilig use i flssil fuels andihe sast ticlsuii'o n if the edrth fir-e\s hi\s nibiniiied t, creait a greatettusioini of these so-called greenhouse

tises The% are griern that name tie.,.ti'ie ts heii the> rise Into the artio-pheie the) foirm a kind of blanket it)

the skt Ih.at let% ii stlat he t biut pie\uts heat filtin escaping the earth s

m ljllionl ,cltC 11)(0 )h 1,kc. .1 r-.11, ! f <t>¢iO

hin-i I lit iet liill' iin' ill Ill ltelperil tlet' *ill iii t,ie hli-i

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elect %%.i souiethin solimlsis h.d .ii

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81

I ii It I L \ 5 I

Ph I) it (he ltielsil if'hi.iiRoklald III N) caliied an iteillaliolnatletll ohll IllII dilloll c lll ,

It% Il1 1964 he ltin cie chalinjn oifthle . llmllll deljlailllt ni at th i ii

o'fIsi 'C ( ,lhfoiiiit .11 If ifie \\ hell

he iiiend fed til Al t'im1. I ltris . ,iil

Ill i sh l Fll t lli iitit aini a i 9hell, ic-'c,h 11 11 1l oI I ah'iedale 111 1972 le

Isi i.ItIilllt! iliit tlI Ile" fields to C\plolt, At iIle \I ( ioileficn los-land lef nied ilil J.lnes I o\cls. k lileunitl lhido\, h lish Scitititst Iest

klo,\sn hIs ia\ thle fCthes of th" (lIIh" , iliesis ha lh alt life on eailh

s1hitih.]t 0I stl ieN.,d a Slligl., III, iII?! Ciii

!ilS .i% ilt! tol i koli IIII tic joul 11.1

in,,, th leh had ileasild ( 1 ( h.i

,is ti e lo\ ,i ,iiiioiii i i h , Ila

Ie I I o\ c1s k Sitlt.gesied la I ( I ( Nilt thli tl d ,I,, atwphei h laci s

but 'tic pii, lhIun .d them ti t to,.el\ I-ifile h,/ad Ross land is i ilt uUsd

lIl the i i,' Itle had dolnie rcsc.hi ,in1thwilIine \slh is one of the ,.,inilsi

neni, of ,hlorolhlwol,.alills as %%ehlAi, l tn ~ h l.11sl tile .1,:l011 Of

light on henials . and he thought iInight he intetltirng to study the esen-tual fate of( i ( s in the atniolphere

Vhen Ro land began his insstiga-tion al L( i[rie ini (itobet i171 theannual picsutnon of F Cs it the USsa,, on the order of 850 million

pIounds )uPont %khich soId theim ti-

der the trade nanie F reon. "as the Ina.

lo doirnesti. niariufaciuret Ross laiddid his initial research v ith .Mat t- tlhna a l'tdss.toral student iAho halljust ie,.eued his Ph F) front [krkele\By De ember ofthat year the i, o si-enlis s had completed their reseafthand in June 1974 the> published a paper in ,uinte The results of their re-searh ssere startling but as Ros landsays There \ias no moment iihen Iyelled 'Eureka' I just came home onenight and told my sife. 'The siork isgoing ser> %%ell but it hooks like theend of the siorld "

Briefly put Rosland and Molinareported that C1 Cs isere being addedto the ens ironmeni in steadily increas-ing amounts that they aren't de-stro>ed in the troposphere the loseraimospheret and that the), sursise formany decades, slovly drifting sip intothe stratosphere Once CFCs reach the

82

slialospheic li1lth i I %hufit

itolllj .'s their and IC.i' , 'I llllocaltIis I fith s Il ilt II 1 1'' I ,1.1 .lstI' .

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'.ii ith

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I h Iked Il les.t'l i, t Its h,0 i,,lklsCr tile ile,

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Ilhell 974 iclli that tliiuul all the( I ( s lhittllnt tletn eleased sinc tire1910% \. -i.et s ilt iii 1fie toss, tillh-

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13

14

thu i llt't iullhuliiui uil u' Ri l|l%\kill Nlml + Il lilt' f .uhllniiigrelt fl i "iick. %l ali t€Lewill it.s

lniil tile" Illitld li1,1n tlfjh lil" llJit-

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olc il 1977 1 lie folloiut IS C illi .lii'i

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,,ttt) Ipiih: hcd lil the I nwlrtim n tii.1

D)ftii(O I Mild lpiojeol. that h) 2025

ihoic klill lIe 11 it)aditiu~nal 1 4 million

1171AJCILCNl Oft )Aill LJCT~I~~ oiver the pre-'

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to/ollt delet~lion

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,if lt" mtmle~l +. l'l Resc'll h onl

83

15

I) II{ I I it R I t

le e fects of UV radiatioi till thle Ii.

"tie s> stetri hAs ben done tIillIt m11eJ1s sttijeits'l Aci. trdliig to tingli~ e"''.oii,I

lestlinlony by Dr Maigatiet I Kikl'te.h.t 1mian of the deliarttien ofi I i1ti-

nologN .i the llnislsity ,f lc%.tsIIete Is n ,onsidt -kfile esdeii.. that

thle LIV rt s dallage a I )i of intiiiiie

Li)I fGimid ,i the skin the I angel hli1.ell mid that this damage leids t

s.it0l i tlt aillsit opt l)mh i .,,l il+%dlead (if' tlet .111OI)l tel la¢inllimmllei,

si,,nse Thus although the inial d.iniage i', I I.alied to the .oLea of skillespvsed to the IV radillotl the le-stl InlIg III i llmn'ogm.gaInI %sillpl Ss0Ill i,S% stIrIIII be-l use the suppi essor

.ll l %i. iiati throughout the hiady'"Not tinl iItltiiniid is at risk I .peli-

teit with tmartne Olanritns ha,,stthstil that IUV radmatiott .ai damagemiittts in the mi.n mite food chain The

Itsitcill fot datmnage it, s getat tin iS4al, high I l Alat let amura a pro-fes%,i of lih~smloivgmctl etcloig at the

IIliiittliIt of Maii)land relIts thatalt hotih Ailic ltiltnts nay adapt tiI IV tadhattii malt, .ati ad ersely af.f t ted by iii.ieasted leiels In teshigher leseh of (IV radiation causedtl;t stIlt titg tti.ti in II leaf treatint rcued pb siol'ii.,l sigor-the

litter retideiuig lhens itei %ulnerablehi IVn1'Its and diseie In a ,1\-)¢ar study

of s tyblns IV radiation \i." ill-

eated ii %iiulale a 25', ledlI1o il

the tvt1ne latei. the result wts a 20 to25', Iis In yields

UOnlike ditiught or either geo.giaihicaillv restricted slresses iO-c.tIses il IV would affect all areas tfthe wii Ild sintirtliatll , Tet nititasays A -ven small teductilns in crtipyield oIt a gihlbal basis could leIad toconsiderable eCi.Ltitoiti ci'Imeqtet1ces '

Altmoist all ltrust ledge tf the effects ofUV tin plaits %iics ftmit studies ofeulivated crti s but these a..otunt fiorIes ihail 10; of the world s segeta-ltin VWe chase little or no tuftirratioronl the effektttilt the tither 9~01,

the foresis gias.slaids Ind shtublads III fiCl there is much siedoit t moss It tos altiit the etetiItif the danaige t hat nia% ic donrebs ( I ( lisiIllg into tihe "k be-cause lnoithiti, tike iIt h.is eserhaprpeoed lwfoe But \%hen itLOnicS Iti rl,Isst\ hin':", 1) ,+ -

atie IhvIet' ale ,arIe l'e pIts'oCedll%thllt ira> gi it s l ' ll of % hti it t

(Mcis the last 2iX) seai, theearth has uiderg n I\o major

changes in chntte I hie trst \iasa \harm period kitrsll (0 .i n-

lists as tihe medlcsl karlil epih. iI isctired tl.ieen tlreye.rs M0t) and 12501 "her, aer-age global %\eirtettite suereaiout the stmie as the\ are io"Certain arel% hio\ese stedistinctly, \ ,i ntre I)trttt thatinte btjrle¢c anid oat. \kerc gr own

in Iceland and In.yarids lour-ished ir IUngland A here sea lev-els iete gradually rising In Bel-gium the rising sea made Bruges.now sonic 15 miles inland, aseap it

Around 9S5, the Viking's be-gan to coloni;e (reensland.which had been discovered byEric the Red But by the end ofthe 13th century Arctic. sea icehad spread through Greenland'swaters and had become such ana igational hazard that the col-onies died out

The medieval ,arrm elophwas soon followed by the I titleIce Age. which lasted from

K

16

D I i I F 0 N E C A S F

about 1550 to 1850. during which theglobal climate was generally about I Ci2*FI cooler than now In India. themonsoons often failed to arrive.prompting the abandonment in 1588of the great city of Fatehpur Siki, be-cause of lack or water The Thamesfroe over several times in the late15OOs Year-round snow, now absent,

covered the high mountains of Ethio-pia The vineyards of northern Francedied off

Some scientists who have studiedthe earth's climatic cycles believe thataround 1700. when the Little Ice Agebegan its gradual decline, the earths%,ung into a period of 1.000 years ofnatural warming Thisforecast. however, doesnot take into accountthe effect of unnaturalagents, such as the in-creasing concentrationsof carbon dioxide. ni-trous oxide and othergreenhouse gases in theatmosphere

What's happening isthis Light from the sunpasses through thesetransparent gases to theearth, where the short-siave radiation (light)becomes long-wave ra-diation (heat) The heatrises from the earth andordinarily would escapeinto space However.greenhouse gases absorbthe long-wave radiation.Thus. the more thesegases accumulate in theatmosphere, the moreheat they absorb, andthe warmer the earth be-comes, In time. the plan-et will come to be likea greenhouse--or a carparked with its windowsupon a sunny day

The theory that in-creasing levels of carbondioxide could cause thisgreenhouse effect wasfirst advanced in 18% bya Swedish physicist andchemist named SvanteArrhenius However. the

a'

idea tx, k kilt %i.i thlig Ile% sugiII14i.i1. .in 1958 when Charles 1) Keeling. achemist and protfesi t( of tti-Lanogia-phy at the Scripl Inshitution ofOceanography hegan nieastittg at-tiosphetic iait bol diw\ide oil Man.,a

[Ii itt llak.ii Stnce Keeling's Inca-Nicitienis Ibg.eii. the oiic'eltitditon ofthe gas has ic.caed esety year IIjunilkd from .115 pirts per milhoinippinil in 195 to 349 ill 1987. a 25',increase from the levels that arethought to ha%e been present beforethe ,ndutrtal age The increase is at-tributiable to a combinatiti of theburning of fossil fuels and the destruic-lion of forests. which serve as reser-

5,siil of k.11l|011 i t 0 10, alsiut100 Il% o( •it tlki ic I ,' h It:" a11J In the,

las~t 40 %cais it i-. et ititied that is

nti'h is htall'l c % oltl % 'oicst-- hateI'ldt de-+otvJ (Ii'clt l 111Vi Cutet"t

tihll of .illl ,it hl.uId ' ,,' xi.'tJed it

tlatih alsitin '111 pl im ll tihe \cat 2010Twit itilici icdihiil cs C IC

aOId Illt"I"l \ let+ 1o ile, \,,har1.

nies The% tic i ,o cd ilhe deple-(titll Of the ti ,c 1,i.c 1 til tile Je fIItltous tivll. ihi-, i- i t tI s is he n the

gas nt\cs, III ti .it lhpuibcre \kithCF 's i Ilu Ji'sldcti tid the ab-sorb helt lcaii,.d Il the tange Ofpills pser toilltii CI C 1onntitations

----------

17

4 ' 7D I i L F 0 R t' C A S 1

i i,'tht wient inweificanlit. lt III:) aic'. .llO1dIIIaIily et.ffetlive he.at ilssog lv.

elt ()ne molecule or CFC. II or CFC-12 cii hlap as muc'h heat as 10000miiculcsifcarbi deoirdv And CICc. vls ate i1.re,smiig at Ilic $te tif 5 to

,iiviid.level Otoie alIv Ntiallfies asicenhow pas It is formed by the

Itf sunlight on litigen o.idrrod h~drocarn pomllutants emittedIi Inlarily by cars and trucks Ve call itsmog Oone has a split pIctsonahltyShtt'spheric o/one piotects tlfe 6)shielding the earth from harmful UViation, ground-lekel o/onc is toxic

the U S alone. according to a stud),de by the En'ironmental Defetnse11d. ozone pollution is responsible

hi annual losses of as much as S2 bil-lion in %heat, corn. soybeans and cot-ton Ozone produced on earth cannotbe used to replenish the ozone layer inthe stratosphere because it has a limit-ed lire span before combining into,;her chemical substances Therefore

Joesn't last long enough to accumu.c in amounts significant enoughreplace what s being lost in the

,iatosphereIn the last 100 )cars, the global

mean temperature has gone up b)about 0 s'C E'en if all emissions ofgreenhouse gases were cut off today.past emissions already make another0 S C increase likely bs> 2050 Accord-

- to computer model estimates doneDr Veerabhadran Ramanathan. an

,onospheric scientist at the Universityot Chicago. the global average surfacetemperature could increase by a totalof as much as 4 SC in the next 40Ncais based on current levels of green-house gas emissions That would make1he earth almost as hot as it Aas during

t Cretaceous period, the age of theksaurs. 100 million )ears ago Mind

It that is the global aierage The;.atest increase in temperatures

-III c ur from the mid-latitudes tome i les %%here wintertime averages, ,uld be 10'C higher than now

Hansen, of NASA s Goddard Cen-to us a climate model that predict).

temperature increase asetaging 1I toin the US hN the middle ofthe 21sti lie also has created a comput-

modJel that predict, tenertature in.

creases for a number of US. cities. B)around 2030-give or take a couple tAdecades because the role ofthe meansis not yet predictable and could de-lay the warming effect-Washington,DC.. which according to Hansen'smodel has about 36 days a year whenthe temperature exceeds 90OF. willhave 87 such days, Omaha. with 37days over 90" now. will have 86. NewYork. with 1 now. will hal : 48. Chicago. with 16 now. will have 36: Den-ver. with 33. will have 86; Los Angeles.with S. will have 27; Memphis. with 65.will have 145; Dallas, which has 100.wil have 162 Hansen's model similar-ly shows an increase in 10WF daysWashington goes from I a year to 12,Omaha from 3 to 21. New York from 0to 4. Chicago from 0 to 6; Denver from0 to 16. Los Angeles from I to 4. Mem-phis from 4 to 42; and Dallas from 19to 78

"Other discussions of the practicalimpacts of greenhouse warming havefocused on possible indirect effectssuch as changes of sea level, storm fe-quency and drought," Hansen says"We believe that the temperaturechanges themselves will substantiallymodify the environment and have amajor impact on the quality of life itsome regions . However. the green-house issue is not likely to receive thefull attention it deserves until the glob-al temperature rises above the level ofthe present natural climate variablhtyIf our model is approximately correct.that time may be soon-within thenext decade"

Dr Wallace Broecker. a geochemistat the Lamont-Doherty GeologicalObservatory of Columbia University.thinks the situation may be even worsethan ir-dicated by models, with theirsupposition ofa gradual warming overa considerable period of time "Theearth's climate doesn't respond in asmooth and gradual way." he says"Rather, it responds in sharp jumpsThese jumps appear to involve large-scale reorganizations of earth systemsIf this reading of the natural record iscorrect, then we must consider the pos-sibility that the major responses of theearth system to our greenhouse provo-cation will also occur in jumps whosetiming and magnitude are uneven and

f unpredictable Coping with this type ofr change is clearly a far more seriousi matter than coping with a gradual,- steady warming "

These models are far from perfect-none of them was able to predict theivotie hole over the Antarctic. for ex-ample--but, for now. they're our bestsource of Information about changeswe can expet to e by the year 2030The view is not pretty

Climate modeling done by Dr Syu-kuro Manabe. an atmospheric scientistat the National Oceanic and Atmo-spheric Administration GeophysicalFluid Dynamics Laboratory in Prince-ton. N J . led him to testify before acongressional committee in 1985 that.w inters in Siberia and Canada will beless severe Because of the penetrationof warm. moisture-rich air into thehigh latitudes, a doubling of atmo-spheric carbon dioxide or the equiva-lent might increase the rate of riverrunoff in northern Canada and Siberiaby 20 to 40 percent Our climate modelalso indicates that in response to theincreased greenhouse gases summerdrought will beone more fiequenover the middle continental regions ofNorth America and the Eurasian content For example, the model-pro-duced summer drought is character-i/ed by dry soil. reduced cloud i.overand higher surface temperature. khichresemble the situation during the du,tbowl of the 1930s "'

A study by the National Academ)of Sciences suggests that water volumein northern California rivers and inthe Colorado River will decline by asmuch as 60- This would lease muchof the West without water SouthernCalifornia would run dry and be sub-jected to an increased incidence of fireas would forests throughout much ofthe West and upper Midwest

Within the past 100 years tidegauges on the Atlantic Coast of theUS have documented a 30-centime-ter, or one-foot rise in sea level Glob-ally. the average is about five inchesModels predict that the level will haverisen by another foot in low-Iyingcoastal regions of the U S in 2030 andby as much as three feet in 2100 Ac-cording to Dr Steven P Leatherman.director of the Laboratory for Coastal

18

Research at the Unisersityof Matyland. at least tat ofthe piesnt sea-level rise on(he I ast Coast is caused byIhe natural con11icti gi andstubsidence of crirstal sedi-imint But at least 4 5 in hesof the rise has been causedb the expansion of ssarmnserOccan surface w atets andthe melting of mountainglaciers. triggered in part bythe 0 5( increase in globaltemperature registered dur-ing the last century

Sea-lesel rise 'All pro-note increased coastal cro

sion. Lcatherman saysAlready approximately 80

percent of our sandy coast-lines is eroding Artifi-ital nourishnient is being

used It restore beaches butthe costs are high - Accord-ing to one study that 'illi

soon he published, the costof maintaining F ast and(iulf( loast beaches will runanvs.here from $IO to Sl0billion A series of arialphotographs taken since

1938 for instance, shows _

that the Blackwater Na-tional Wildlife Refuge on the eastern,hore of the Chesapeake Nas one ofthe most inlsitiant Last ( oast %%atcifowl I sanctuaries. is in a t,late oifdisintegration because of rising sea les-el Human activity can hasten suchdestruction

ime of the other threats ixpsed by aone- to three-f(t rise in sea lesel in-clude increased salinity% of drinkingwater, saline intrusion into river deltasand estuaries, which would impeillfisheries the inundation of Aetlandscypress swamps and adjacent low-lands, increased flooding in populatedareas which would ncessilate thebuilding of costly flood protection sys-tems such as sea walls, the disappear-ance of beaches all oer the world

Then there are these further dire

possi hlitles* Studies by meteorologist KerryE manuel at MIT indicate that moresevere hurricanes are likely because ofwarmer oceans Stich storms could in-

creaise iII ferxi t% ) Iis nitih as 60',oei current n i u\1I111UI1"I# Radio al ch.Inge Iii the -Ailaiclic ices.heet couldi bhse seie sis~unAntiarctica h.- 911, of the worlds Ic:onl I', is liked ul in irroutl i1 gla-

cteiiI If the Anlarci t, s sheet wertto melt rompletel) the global sea leiel%ould rise IS to 20 feet No one es-pects that ito happen At currently pro-jected rates the greenhouse effect andglobal warning are Iot expected itohase a major impact on the Antarcticice sheet for several centuries But noone predicted holes it) the orone layetand as Dr Stanley S Jabohs_ a seniorstall assitate at Ianmni-Dohert)said iii a recent arttle ill (A i nitimiag.ine "Antarctica itay he a wildcard in the deck, but who can say thedeck is riot stacked, %ilh Nature set-ling up the sting "'

('ouple all the greenhluse effs.cswith inciteased ultrasrolel hadihlio

and we his e w ritten the piescii1lion

(tit dl'1JN If C11; , 41,h.Il %%0.1. 0lh 11% h'a

and fltItc.ilIt Is laid lriio s I' asstric that %%4:

could .1t ails Idt)t sti'l Ii lirirelfras'r Us.i!oles ofs .,et s, I i~...1 1 as

ter %uliplies tt.irs oritailt.i i t .and land use antitN has ec o khedrise celltIut w. iti iesm totsite atie tngclimate " sys sy r (riodon J Malnon-aid, a folrnei profe,-i olfgeoph)sis.I

Dartmouth wkhos now itirciidentand chief scienti s of the Mitre Cortsa-ratiol io lolpitrolil lese rh orgalmla-tion 'Significant lchiges h iii cloiiIeMnCI decides wifll es\eit ltirf'ouid do%-rulptis forces on the bailaice of tirfia-

MacDorild is talking altit infra.situctulres that ate lead% in placeBut corliorations and get ,elnierlrithroughout the world are ros irakirigbig slecisisris 0%)rU1 Irigiler lit I)Isjectsthat ins olve coiitalI des ehriitreilirmtsiie lard os \itpatiorri hIdir-electric lwrsser oil espilorationii attial

69

-l

19

RISICGS1A IEVEISCOUII)AIwSRSu I SII( T II)RISIIKI LONIX)

gas. tic Nearly all of these deisloiis nilii.an si1tningof the global climateare being based on the notion ihat ihe 1in the nest century It is a matter of ur-

Iriate of he recent past mill co tuinueinto the future This is no longer a safeassumpIlon In October 1985 the',\.,i1d .Mge1oologial (la11111i0oi0ith International Council of lientifii'

Sions and the United Nations I:n i-ronmeni Programme consened a son-ference in Villach Austria at shihmore than 80 scientists from 16 .so1n-tries assessed the chlmatic changes thatcould be brought about by the ,icumu-lanion of greenhouse gases The scten-tist% concluded that using she cl anteof the tecen past so plan (or ihe future

is is, linger a gsswi assumlpisis %i1 ethe ii1 reasiig concentisun ofgreerr-h house gases are expited It cause a s ig-

gent: tsi it)itnc estimate,* of the futureclinrare condiitons to irprose thesede, ions

Di Mijhlel ()plpiheiiie. a fisnierJ|lit rid asirophysh isI ,% ho is io s% se-nwis ,ItiisslihclIt: scic1iril kuith the Fn-\ionmesal IDefense I und. puts It this

,J % We r flying blind Intot a highlymi ertari future These changes aregoing to i.tlet etery htnialt being andesves ecsiss e n on she face of theealih and %%c only hae a glimmer of"has these st|inges d sil he The atmosphere is , slisol u to do lwo things forus Ira r rr1irii a I onstat chemical clitale f oherp. iaolsiith arid Aater

s ausii.ind help mnrittainr ihe radiation

I) H I | ii I i s , T

bulance fri exiniple. 11) kIpeeig 141ness.s IV The unthiikaltile is that

we're di' loI Iiig this ,lsiospheric hil.ance We're shiftintg the chemical hal.anc.vs i ait . ev hae nmote pusi ss1i, Inthe als opsisci e oaie and aicid I.I111

on1 F.isiid lesel %k hilt Ae it also,cha1 lgii , the setlrlal e1itIIate of thehearts ihsough the gienihoise electand el this simulhni-Ously taus-Ing dest I uiot Iii of u pf i,1iy lWtt ofuliiaslei light Its intsrediblc Talkaboutl ihe itatiosral-dchi I %.isiN-sue repiling up denits iu the ainiosplihle andthe piper "III usant to IVu paid

Th fit e of the earth inos on pisti-

cait deuimiis 'uhih dosset lecessar-ii) make it holviekss I t Ol ic,:etilthe Reagan Adn1irtrhtioi has doneltle is deal wih the ,ri is of ais .-

spheric itlluiion Whein she issue hasbeens addiessed it a hitscsr Liigcls atthe plodding of mdi dual lgiseisorsin use Senate li Relubliais John(hafee of Rhle l slaid Rotwfi. Siaf.fold of Veigmit ind I)ai: l)uienter.ger of Misnne-s.il and ImnlsliatsMa' Haw5 us of .olli.tia and S ,eOrgeMitchell of Mine all netnrss ofihe I n ,vlsniclit anid Pult. 5WorksConmoittee

Alberi (;tre the Tenniessee Demo-stat mhos nonv i ssaoi led hearingson the gceenhou ,, eTes %k hile he %asin ihe Itouse in 1981 and he s the hrstcurrent presidenisat caiididate to 5 disethe issie Indeed (sore , s lltinges todiscuss ib is I -IolI h ill % u n p piiu ,t r ub-jecs plonipled coluuinst (eorge Wiltto chide hint for a sos suniig interestin I 5su that are in the eyes ofheJlc-orate not esen peripheral BLuIt as

Chafee says This is not a matter ofChicken I tite selling us, the sky is (all-Ing 'The s, reiIli s ide e I telling ussue hasca problem a ssious p!ollem

lortunately ii s stilt iivsible toameltoate the dairiage leres , hatue must do

* Reduce pr-,ihictosof f (1'C% hi 9;

its-i Chafee and tauus hate intro-du.ed hsillss allng for suth a reductionIast -A Intel ( hafee told CI C manu-faciuneis 'If the si.- tIo eighi.)earphase -out in out hills is unrealistic tellin hou nuh ionie you need and shovus hokw you AItl use that lia'e We are

90

,20

SOWE PRI)ICIAl) (IIANGIS WARMING I\ SIt RI' 5%I) )NROUGIIT IN CAIIF(

o1i" Is to .siirgesilons hill the buidtesis ill %tl so just-f( a lrnger timeframe ndouhbedl) there isill b

kml5itt$lntl\ that se . 115ot iat'het

IN It is %Iell tr leall that the bll onaeor still te U S caused pltocik liolt*o(+FI , fr, rerosirs to dol tO lesthan 25 million lx)uids ,,i >ear.later Arid rms ousti\ usl\ed I lirsnot cost\ir, ed that Aiesiican ot airsother piodkie s hasr: a cornsllUtion;1iright tso osisisue to ftl NJuce ptlidu 15

that cause permiianent hate s o ourworld. to our citiens

It Septeibes the I S and 21 othercounlres inteed a treat% calling fist a

50O, tat iss C IC production bs mid-1999 but the ness findings fioi theAntarcti. demonstrate that the cut isneither big enough nor fast enough"'We've got it beat the cstx:k sass

Rafe Porierance a ptilnc analssl swhohas be n followi sg the ozone problemrir the \ioild Resources lns itute inWashington DC . fir the past Issoyears " If the data from the Antircticcontinues to build osei the iest (ci

nminths, se ray hase ir ieionseneand stietefi tire treats

* Riditi, d,.l~esc/re uo ir sil huml+Vie sh,id foixus til niscieriental steps

that lini ti our depenideie till csal andtill Otrttniheimser wsays I clts fikstol the doable Nil I c.orissetsallsnI hc I S sill uses i- we is nuch eni-

g\ ler call a .i the I utopeass sit iist"5 it. i n. i a l %ir1i1n1€ site skass rg

ersesgi arid s+e're prodtucing tols tush-ii iltl sloiii de c'ausc orf titl l sese,

issieren, oi fr,,is fuelsReliance si these furls ,.a alsij , be

iedu. ied thisugh gicatet use of nonpol-Iluting alterliatise sources of enregyl.ar Ipsser is a prime example but

the IU S seems tsr ha\e giketn up l.tder-),hill its photirssilsatc rewar ch arid theJaanes are tiw forging ahead Phisorsltait technology proilse% ti deh\ -

ei encgs at a reasonable price viothi uIissislOtuIng lia.' bu divide* Mii ielot d isvitis "oui have ti dirt\ks thrugs i)s Dr (eirge M+

\V'islAsll fosrier president of thel cologial ,iciel) of Amet sca andnov, director of the Wioods litleiklass ) Researh (enter ' Uirst, )ouh,\e ti stop deforestation around thes world. sit jut., in the 1tispics and you

hase tsr do ii onl the basis of an inter-

2P

1. ti 11h 1 l~lJ I44 oo Sec.

ond yout hase io have.ir equally intensiveMid insagirsatise prolo-co that call fsr refor-eltatlhl 'io as t storern11e ir(iloiort. of car-in imtially A million

,qai.ile kilometers i, 600lllhltik 600 miles andsr: \ kill probably has, iorefoies on the order offour 1111111441 Square klloInsefs Iwo sear cergsss- land to do the job

irs ituissr deowied i has$cetip etaI)IPIl Ii l(h

Sa)s ()ppenheintr "Weneed a national commitmnii +onilwa.le ti the,hin hiIltdn Ptojeo notoirni s Ae ,i in under-

tar1d \%hal the tslii .tUfl,CN f ogloal changelife (I Iai but so thut. c .ita be in the fire-fwos.t of the deselopmreni

of aliernalis ene, g\ souies that si illhelp limit ihi plhlem I errs iron anultbillion dollar -. ientli" effort Itsas in1i 1osti ts inaIhil defense It ifthe riatoial defense If se do nothing".iasslsg fol the atioiphefe so hawge

and for Utlless¢,isJlll 011WeqUelh to!t .kii it iv ill t t O, te for it, io asinnd

diii sipllis e .fled des aia ingl #htls1 es,

* [) ir oitnitn o hastir i -ioosn(wwtiI i

hsei b /it ot .'sihd/ hi I+P-4 rid the

I),i'J4,rer w1 Ep r-e I Thec igentc esate unteliable be.aue theN ate hea ilyinflux ced b' political pressures LastJanuary. roLker bluntly told theSenate Subcomniitee on I it, roninen-tat Protection , I believe that rilst si-entisis vtould agree \kith me that thehandling of research on greenhousegases by D()F (the Departmcnt of Un-erg I and ons acid tan by F PA hasbeen a disaster

" ill the siorld at ir trne I AN RoA -land Aho von eight aisity letters ibasketball and baseball at Ohio Wes-le.an and the Uniscrity of Chicago.puts it "The key thing abtrat baseballis there is always tlest %ear anotherseason The quesowIt for the earth riovtis \%ill there bea nest Neat "'

21

A24 STuavRi. Juv 11. I1988

A INPENInDto A

AN INDEPENDENT NEWSPAPER

Living in a GreenhouseLAST YEAR was, worldwide, the warmest on

record. The four warmest years in modemhistory all fall in the 1980s. There's a good

deal of uncertainty about the rate at which thisplanet is getting hotter, but there's no doubt aboutthe direction of the trend, or the reason for it.

The ingenious inhabitants of this world havebrought themselves to a level of industrial devel-opment that is changing the climate. The chiefcause is the gigantic volume of carbon dioxidethat they generate by burning all the familiarfuels, but there are other gases that also makeimportant contributions to the temperature. Theyare building up into a chemical blanket throughwhich the very high frequency radiation from thesun passes easily, but which traps the heat thatthe Earth would radiate back at lower frequenciesinto space. That's the greenhouse effect-thechemical blanket has the same effect as a sheet ofglass-and the speed with which it changesclimates will depend on the world's ability toreduce the emissions that are feeding it.

Temperatures worldwide have swung up anddown sharply over the centuries for entirelynatural reasons. In recent history the world gotcolder in the 17th century, on the whole anunpleasant time to live, and hit a low point earlyin the 18th. It grew warmer for a century, then

dipped again in the early 19th century and sincethen, in an irregular and unpredictable pattern,has been getting warmer. In recent years man-made emissions of insulating gases have appar-ently begun to overwhelm whatever naturalprocess might be at work. The present changes inthe world's average temperatures are measuredin tenths of a degree Centigrade per decade, but afew tenths of a degree is enough to affect theclimate perceptibly. The warming since the lastIce Age may have been no more than 5 degrees,and in the past two centuries, geologists haveseen glaciers advance and retreat in response tovariations of a fraction of a degree.

A prolonged warming trend would mean arising sea level, changes in patterns of precipita-tion and perhaps even changes in vegetation.With the return of summer, perhaps it's a goodmoment to ask how far this process of unintendedchange will be allowed to run.

Congress has asked the Environmental Protec-tion Agency for two reports, one describing thegreenhouse effects now unfolding and the otheron the possibilities of restraining and stabilizingthe accumulation of greenhouse gases. The re-ports are to be published at the end of theyear, just in time for the arrival of the nextadministration.

/

22

Clnoe Experts AskIfDro~ught Presages'Greenhouse World'

By WALTER SULLIVANWeather specialists studying the

druaght in the Middle West this yearhave determined why H occurred. butTEDSTES

ey are wondering whether k Is a har. a O nt a n ~IngT ON thbts to come, periami evi.doea of basic c16n16 in climate= 0t about by the greenhouse ef.

Por msenthe a great wall of hioh pres-law over the ce o ln" United States

a d sms bearig rain and Th current drought reoulked wkiM te jet Orten which direc0- oMeneSfrom pooetratig dotacvty, spi to how amd a dswanm high pressure zsoe in the mod-

dto s dio the cow y. The we. broqht isrn to Am s 1 a 1 0weeew service. h hig pressurewm bcled is piace by a jet stream far dock Ordua but met Ove MId West

As a result, Oe aeacy said yester.y,. proclpIe0 W been abnormally W. Sleclitao at h Unversiy of Ar- Worms away, leadt so low precipiel-

IO In he olbM ot sad Ose Neort UPa coul determine, frem vie wIit s there.west even as the Middle West has suf. of annual tree rings in much of the The high pressure iall then moved1ered. West, whether droughts In the last east to Its present position over the ceur-

A Chae . h Weather? three centuries had been as prolonged tralstates.and widespread as this one. In winter and spring, according to

Concrm was expressed yesterday Not since the dust storm period of the Dr. Donald, Gilman, long-range fore-tht de resulting drought might offer a 1030's, Dr, Hecht said, has a drought caster of the Weather Seivice, the.jetgalmpse into what Dr. Alan D. Hecht, been so extensive. He would like to stream normally heads east afterthe djector of the National Climate know how exceptional this one Is. crossing California, carrying storms,Proram -Ofe In Rockville, Md., over the Middle West.called "the greenhouse world" of t Rings and Rainfall This year, however, the jet streamituture. Annual rings In trees growing in the has split. Dr. Gilman said. The main

Ilthe drought, he asked "the kind of region over the last 300 years have branch has swung north across Ore-thlgwe will see more of?" been analyzed at Dr. Stocktop's Labo- gon. Near Hudson Bay it has curved

A number of weather specialists ratory of Tree-Ring Research at the southeast across New Hampshire andhave been searching for signs that University of Arizona. Researchers are has Joined the lesser branch over thewor climate Is changing asa result of trying to find out whether occurrences Atlantic Ocean after the latter haswarming caused by carbon dioxide of narrow rings, indicating drought, crossed northern Mexco and Florida.from the burning of fuel. This is the conform to a 22-year cycle of solar ac- The drought now affects most of the

muchd4isased greenhouse effect. tivity. The results have been Inconclu- MIssissIppi-Mlssour drainage sys-Wih the information now available, give. teams. reaching from Canada-to the

Gulf of Mexico. The rivers are ex-Dr. Ret aid, an obvious relationship David Miskus of the Analysis and In- tremely low. The Tennessee Valley hsI still uncertain, formation branch of the National been'short of rain for several years, ac-

Dr. Hecht, whose office is part of the Weather Service said that from cording to Dr. Gilman, and the short-National Oceanic and Atmosphric Ad- December to February a high pressure age has lowered reservoirs enough toministratlon, said he hoped Dr.tharles region off the West Coast had Jept threaten power production.

4.

23

Africa, Asia to Suffer Most From'Greenhouse Effect,' Study Says

I

Tht WASHINGTON PosT AIO Tumsmtv, Iut 7,1988

By Michael WeisskopfW&W40gtu Ng Sun Wnu

Global temperatures would riseone-half degree and sea levels in-crease more than two inches everydecade if 'greenhouse gases" thattrap heat are released at currentlevels, according to a scientific re-port released by the United Nationsyesterday.

The projected increases dwarfthose of the last century, and theirimpact is expected to be greatest inthree general areas:a Semi-arid regions of Africa,where hotter days would aggravatefamine and drought.a Humid, tropical parts of Asia,where higher sea levels would in.

crease risk of flooding.a High latitudes of Alaska, Canadaand Scandinavia, where more ex-tensive ice thaws would complicateeverything from marine transpor-tation to construction practices.

A more moderate outcome is ex-pected in mid-latitude regioms, in-cluding the United States and cen-tral Europe, where the report predicted thinning of forests and localdisruption in agricultural produc-tivity.

"We're leaving a period in whichthe Earth and the human enterprisehave passed through substantialclimatic stability over centut ies intoa period of very rapid change," saidGeorge Woodwell, director of theWoods Hole Research Center andcontributor to the report published

by the U.N. Environmental Pro-gramme and World MeteorologicalOrganization.

The report grew out of two inter-national workshops attended lastyear by top scientists and govern-ment officials asked to refine projec-tions o the *greenhouse effect" andto recommend policy steps to curb it.

Scientists have long warned thatcarbon dioxide released from coaland other fossil fuels burned for en-ergy accumulate in the atmospherewith such man-made pollutants asnitrous oxides, methane and chkro-fluorocarbons (CFCs). trapping in-coming sunlight much like a green-house and warming the temperature.

Although scietific bodies havepredicted that doubling emissions ofgreenhouse gases would increase the

world's temperature 6 degrees andraise sea levels, yesterday's report isthe first to estimate how fast andwhere changes would occur.

The study projects different cli-matic outcomes for different levelsof pollution. The half-degree in-crease per decade is based on cur-rent emission trends and imple-mentation of an international agree-ment to halve CFCs over the nextdecade. Temperatures rose at one-sixth of that level in the last century.

With a significant increase inemissions of greenhouse gases,such as a five-fold increase in coaluse by 2025, temperatures wouldincre&9e about l.Gdegrees perdee-.ade, according to the report.

Stringent global pollution con-trols, such as halving carbon-diox-

ide emesions by 2075, would resultin a slight temperature increase.

"Without exception, you see thatall of those are rising trends," saidWilliam C. Clark, a Harvard Univer-sity ecologist and study participant.He said rapid growth of greenhousegases would result by 2040 in tem-peratures warmer than "anythingwe've seen on Earth since humansocieties were developed .... "

Warming trends vary regionally,with upper latitudes of the North-ern Hemisphere facmg the mostextreme temperature increases in

'the winter, as much a 2V timesgreater and faster than the global

-av rage.- .Temperature increases in the

mid-latitudes, including the UnitedStates, would be close to average in

smmnn while sOmewhat higherthan average in winter.

While sea levels would rise 2.2inches per decade at currt levels.f pollution, the increase would be9.4 inches every 10 years with rapidgrowth of the gases. Strong controlswould result in slight decreases.

Any rise in sea levels would aggra-vate the erosion of beaches, reduceavailable land for such activities assalt making, decrease wetlands, andincrease flooding and damage to portfacilities, the report sid. Woodwesaid the im ct would be mos se-vere in the deltas of bouisia"a andalong the Florida cmstline.

Michel Oppenheimer, an atnop-aberic physicist at the EnviroumeatalDefense Fund who particisted inthe study, said a solution musrt be

-impienumted to soon as possible in-chiding cutting by nearly one-thirdthe amount of fossil fuels burnedyearly.

24

LOOKING AHEAD

A WARMING WORLD:Rising global temperatures could disrupt wheat farmers, electric utilities, and military strategy.Which companies win or lose depends on how well they plan ahead. U by Ailiony Ramirez

A i Il .l % I'4 1 (l is'11 iled o n li tA iaitig the nitire to conpic 1 hcIdlit Sri froze over l t ic. iti

I 103 ard 1 16-7. karur foll)iedoft;nsr-sortabhl (old. illnors. arid rait, and a rise

in the level of hc (aipian Sea (xtcml,o-ares ould not knot4 it mas the onset of

%4 hat ha% sincc been rcofriied as the 1it-tie Ice Age lastin until aboul 1704)%of mere thet ei aiare that. otrnip to theclimatic chan e. communication ithGreenland oas gradiiall einv'b Ing t. thatthe Nkoirse , stlefntnti (here aere being cri -on.,uithed. that cultvation of jrain Ata%

dis apearn' froni hclanid anti t-iig sc.verel) reduced in St andinavi a

- RBarbara luhmian, A Dilant trior

I tie ihe 14th ceniir%, the 21 .i century i,in for na iry ither-but of the opl,wisiekind Although the earth has undergone pe-riods of starming and cxooling i the pastsAientims doe fowv gencrall> agreed thai it I%abotii to heal up more-and facer-thanever 11) the likeficst scenario the resultingclimalt change, %vill Ibedesil farming. %hip-ping, internatiinal trade, energy pohi.),and military stratcg) Coping %%ith dramat-ic global swarming %ill not be eas), but ig.noting it Atould be foolish The best betsconserving energy and using alternatorc en.erg source., including nuclear poster

The threat i,, clear Carbon dioide froimthe burning of fossil fuel like oil, coal, andgasoline is rapidly accumulating in the at-mosphere So are pases like chlorofluoro-carxios ('.1. Ahich are far less af-un.dant but equally) deamtating COI. CRCs,andt the ottht gasc ome almost entitlfrom a arict) of rtin-made source like ve-hitle cxhausts, and Industrial siitsents (rsa m idisi amount derive%. frrn naturalsour%.s like microhe% in the soil In the

tmlh's antmosphere the gascs act like thegtt, in a ginetihous, whtih le, in ,unhl lbut traps heat B1y ahsorbing rather than re-flecitng the infrared radiation that produLc hiat the) are hiinginp a iut the.elentls, warning of the planet knon as

the greenhiouse efct (we hoi. page 1041"'Mi+ filing is thit there'% nti wvay totop

It." s . Walc Robe.s. president enterius,. ile Na.lion:il Cnler f(or AtmosphericResearch INC'ARI in tBtulder. Colorado.and an organi/ct of .i year-long United

13 POSSIBLECONSEQUENCESOF THEGREENHOUSEEFFECT BYABOUT 2050

States- sie Union conference in globalwarming that started netting in May "Ima) he a little bit smaller or it ma he alittl hit larger But the greenhouse effect isgoing to come." He thinks global depcn-dence on fosil fuels i so sast that it make%

(

"Q FORTUNE it tIN 4 isxi

')i

25

N'HAT IT WILL MEAN' titii in i gig f ginn l aoaJJ ip'r.i gJ|in lit reduce( ( ) g. ggii giigm tinlikul)

1ki. ,g " no ,l n,,: und riand%. ,ill the % arn-:glth- ela.a glici lie carlh' tenta'r ragtuire. it'%nloti *ghilhih certa n that he greenhou..cdiet i "ill .irrie ,is predicted iii ahal all it%

dirt prtoig leuicti %u iin ¢u cn. ill ctaua.tll)t.ur iwc . Kv++ llJgv IWO, Some nimlll i~lng

ia girs evi1i itid.gq. and oithe'r, hia) emerge.' the efleci¢ ilt'. Fair ef r ample. vhtle

claud' high tii 11e atlnr,,+,phiri. .mid It, Iraiph ealt. it'-)a l it g c g g ed t aid t rC fn e l gllgn-light 'loud'. it h a high nloitugrca onicnthaive an even greater coouling effect

Ficn -A,. tlie anIaic ggg' gi11n111 ia MeaJ

urged b) th gloah l mcnii ianifptr.atare. I.iLw)eJr %a'. the vijrnie't year gin revgurd. the1980s are the -Aanre a d,':.ide in a cenitiryA re in the earth'. leniper.litlir iii a hatg.2 or 3' Fahrenheit 'eni' inevitable h> lh

nid-21, h.engar). %iken the ioncctnlrationoh CO, in the atimiuphere iuu lilel) it) he%4411i 60W greatr thin itad.) and doublethe leiel that prevaeuled before the Indusiri-al Retailumign A temperaitre incrgeaw ofmohggre than S' F it po%,iblc

Ju%.l , 2 ,miriny could haiver draniaticeffeci'. Since that 2 ivant) an average figure,muc-h Iirger Ieniperaiure inrcresu t iuld taxcut in certiJn platee. and ,ea.uno% For in.

Sovicttk Circle: Pitts in Sro in. A7 , __n srtie of 40 dy bbt mofe €a w the . ,Mnelts, rd "a eo e i to pnewe we bii-gte much of tOw pw, on-1 ix-in. hancing commercial shippiing. But

eAterican &W Soet nuclt escm arsetswre dopirfvld of Ice cove.

8 Soviet Union: Its growing season

W~rthens by 40 day, but more drugs

.t. assuming the warming aul I /am Is not disturbed by changes 10 igtt on by flhe greenouse effect.M .. *. ~C~ee may get mere rah. Iftbe YMe&a

W&11 e, w a.. gt esh Bothe we bat. .toted h mere tby=m m- ed = Roo /

i

bef mov li iaiwet ac

• . ++" )/

13Antarctical: Increased *new am

frikJ ramn tdduan the Ice €iww will co-toarct sam of the see kyel rise po

26

LOOKING AHEAD

,IimIv oInt" \C[AR t.ipuler %ill]-Mlonl

r-i.k, . ho, spot niriI the. Hering Sea thatkoild is.' ie.irls 10 iarnier in winter thini~si ih too tOO maolt IAide ussling of onli,aN111u ? pc hip due ,i drop, in t i'tli ridim to tiu,v: the t ittle hke Age¢ thal

%%rtqihl i1.14%, in the 141h eniur+, 1 hi%%j% o lh t nilr vtobbli:e ompred -A ith

intl *i licrin i,.Lilll~tiions thmil cC.1u; 0% er1t1. 411Miilleitinim A ,eeniiringJ) mill teM-pci.liitre hili nietil% the difference be-isen ta in spells and true ice ages( iiih/.tion h.i, deliped in a nirrosiKind of l 'ml .intais nes er nrore thinstiter or ooiter. tin tiier.te, thin io-Jait'sA %..rmni: of otier the nel.t 60 yeurs ir%,0 O iUld equal the enire ruse in global teni-per tiure sunt the glatters began their loi+retreaitl IN (NO ears ago

disiturb the .hrlmte of the plaret+changing ,uh criial saruahle, aranfall. wind. clud coser oc.:-n

currents and the extent if the polar ice-taps Although counit)-h)-uountr. tone-ijuences ire fir from clear. ,cientits. a'cconhsdenl of the overall trends Interior, (ifcontinent will lend to get drier and co.isi%wetter ('old sex,,ons woil shorten. aarmsa,,sons lengthen Increased evaporation%kill lead to drier MN, oser wide areas

The ripple effe,s through the Aorldeconom) w ill ie enormous as shifts e tO-op in ,oil conditiow. crop yield, salnity ofwater supphe,. and the utilability of riversater lor generating h)droclectrrc possrEngineer, Aill be hard put to it to anti-pate future tresses (n structures the)build "It may become difficult to find a sitefor a dam or an airport or a public iranspor-tation %sten or anything designed to la,,30 to 40 )ears." says Jes Ausubel. direc.-tor of programs at the National Academyof Engineers "What do you do when thepast is no longer a guide to the future""

(oernment officials and corporate cx-eC+utoie are lowly becoming aware of thehazards of the greenhoue efel, hut feware thinking of long-term strategies Globals ,,rming was a minor item on the agenda ofthe Reagan-Gorha.hev summit last 1k-cember. the U %, and the S.v)viet Unionagreed io prodec "a detailed study of theclimate of the future "

V'yerhaeuser. the giant forest-productscompany in Tacoma. Wa%hington. worriesautiu ii nearly two million acres in Okla-htma and Arkansas. %%here some climatescientmit project a warming, drying trend

Rofitcted

Co. Ndether

Ice

I'I

ROltelId

Tri

~Th2HOW THE GREENHOUSE EFFECT WORKS

E The earth grows warmer or cold-er mainly because of the effectsof sunlight in the atmosphere Clouds.snow, and ice reflect some sunlightback into space, But the earth absorbsmuch of it, converting it into infraredenergy-heat As heat rises from theearth's surface, it stnkes molecules ofcarbon dioxide and other gases, settingthem vibrating The gas molecules re-flect some of the heat back to ea th, in-tensifying the warming effect (Forsimplicity , the illustreiton shows thegases as a band in the atmosphere, infact they occur throughout itI

The more CO1, the greater the heat-tng The earth's atmosphere containssubstantially more COt than it did be-fore the Industrial Revolution. By ana-lytng cores from the ice sheets thatcover Greenland and Antarctica.which enclose trapped bulbles of cen-

tures-old atmospheric gases. scientistshase concluded that in 1750 the atmo-sphere contained aboat 280 parts permillion of CO) Today the figure ts 344ppm, nearly 259 higher

If that trend accelerates, as most sct-entists noA believe it will. at somepoint between 2030 and 2070 concen-trations of CO; wtll rise to between 1.3and 1.9 times the preindustral level, or367 to 531 ppm In general, the strong-er the world's economies, the moreCOl gets spewed into the air Scientistsconsider the near doubling of COmore likely than the modest increase.

While CO, produces half the green-house effect, methane from such activ-ites as growing r:-ce and flaring naturalgas wells accounts for 20% of it Othersources, chlorofluorocarbons (CFCs)( ). nitrous oxtde, from fertilizersaPd microbes (10%); and ozone (5%).

It I MStRKAIiNS BY aRAN W SLNRAUGII

4

1( 4 FORlTUNE Jtljt 4 19M4

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I lie ompans is iryitig h breed drought re.sis.ncc into the iree varieties iI will platnthere lirilihi Petroleum, which has %pcnl$ It billion on oil and gas operations ilAlaska. ha, a pirtcular interest iI thegreenhouiie problem Drilling rigs. housing,roads. and the Trans-Alaska Pipeline are allbuilt on pernafroi. which could start tothaw in a warming trend BP has followedthe %cientific debate about the greenhouseeffect. but at this point believes it, ine,.t-ment is safe The reason BP's facilities reston gravel pads that Insulate the perniatrosibeneath them

Both Alaska and Siberia hase warmedup sbout 2 7' in just the past 20 )ears, ac-cording to researchers at the Universilt ofEast Anglta in England, Says Michael kel-ly, a climate researcher at the universityand a consultant to HP "We've now startedto warn British Petroleum that 30 years out.greenhouse %arming may have moved cli-mate beyond the range of the conditionsthat have prevailed historically "' BP i stillstudying the East Anglia warningW HAT FOLLOWS aren't hard

and fast predictions of what

will happen between the )ears2030 and 2070, when carbon

dioxide concentrations are expected to dou-ble from preindusinal levels The) are"plausible possibilities" suggested by com-puter models, as Howard Ferguson, assis-tant deputy minister of Canada's Atnos-pherc Environment Service, calls them

Some of the most obvious effects will ap-pear in agrculture Through photosynthe-sis, plants make carbohydrates from COand water. As carbon dioxide concentra-tions increase, a plant's stomata, the poresthrough which gases and water vapor pass,need to open less to take in the same"amount of CO. so the plant loses less waterthrough evaporation The upshot. Theplant gets bigger.

If some crops grow faster, they couldstrip soil of nutrients more quickly, forcingfarmers to buy more fertilizer. Food qualitycould deteriorate as CO, levels increase,because leaves may become ncher in car-bon and poorer in nitrogen Insects feedingoff plants stimulated by CO, would have toeat more to get their fill of nitrogen. In-deed, hungrier pests and damaging diseasesmight thrive on the greenhouse effect, forc-ing farmers to buy more pesticides as well,

The social and political consequences ofthe greenhouse effect are harder to aissThe Dust Bowl of the 193s pushed mil-

lion% o Mid-lc-itictsls % %iI (tilitirnhlr.in the 140(k tit ItOt. tohbs ind fctier

weilher poliths imoiis mihinlit froi IhsNorheaj io Ihic %liiiblth I ,y1 I ).iilRind, i ehiniatc & itcii.i % tl it (t e od,aid

Institute for Sr pitc St ilte, in Nrw YorkCity "Yti ni. in get n its n tutnt iii theSoutheast and Sotiihies inttore Itreaches 129 in PhIenis. now Will people

still ive there it iI's IIt0' 14(Y' " Accord-ing to James Hainseti of the (Gixidird Itisit-lUte the maitinun enir-eralure in Dallascould exceed I(S on %ons-ihitig like 78

tUmLSFROM -NThe U.S. accounts fo about one-fifth of teworld's COx omlssoln, Md gi of thesecome from buning flostl fuelis

days a )ear. the current average is just 19If American agriculture ;s battered by

such punishing summer days. and Sovietagriculture thrives owing to a longer andmore temperate growing season, whatwould that do to the balance of power'"The United States could become a grainimporter and the U.S S R could become agrain exporter." says Roberts of NCAR"At the very least. it would be a maior eco-nomic. political, and social dislocation "

One of the most discussed--andfeared-conequences of the greenhouseeffect is a projected rise in sea level, result-ing largely from thermal expansion Likeany other liquid, water increases in volumewhen heated But most scientists believethe rise will be relatively gentle, on the or-dee of eight to 16 inches, making it a prob-lem mainly for ciuntrte% writh large popu-lavitns near or below sea level, such as theNetherlands and Banglade,,h

Geographically., lthe grpeenhoue effect is

likely it) hase its, gieae't l ip,l tin i he highltliludes of the Noriliern Henisphere. the

broad band from No norlh-roughl) the l.i-Ilude of Anchorige nd ti1. I, htohi-tih iheNorth Pole A feedbak e ,le. itceniuateisglobal warming in ihc hight-r litude,Snow and ice reflect unlighi into space,keeping tempeiraitielioni risiig Ilut as theglobe warms,. th. Mliitig Artic ice coverstarts to melt. leasny Is, snirs and ice It,reflect sunlight--enhincit the warming,which in turn melts more snow and ice (inthe Southern Hemisphere. %ci ice will alsoich, But the land-based Antarciic icecap is

so masive-it avetages Iwo miles thick-Ihi it would lake centuries to thaiw )

F THE ORL) as a whole warms Yby midceniuts. the higher northernlatitudes mighi become 8' or morewarmer in winner If the global aver-

age rises g w iniei temperalures in thehigher laitudes i.ould gi up a torrid 19'"The fabled Northwest Passage would beopen.* . Wal Ritberts of N( AR, "Youcould vail from Tokyo io lurope in halfthe time - May b so. but British Petro-leum and others are beginning to worryabout the hazards of pack ice-large, flatmass of ice that predominate in the Arc-tic Ocean-and icebergs, glacier chunkslike the one that sank the Titanic. thatflo.t off ihe coasts of Newfoundland andNova Scotia "Tho icebergs would endan-ger ship and floating oil ri&

The Arctic ice coer could also causeproblems for the US and Soviet defenseestablishments The polar icecap of theArctic Sea helps both Stiiet and Americannuclear submarines avoid detection. Theeffect would be more damaging to theU; S S R Because American submarinesare faster and can travel farther than theiroSvie counterparts, the) are les depen-

dent on hiding places under the icecap.The Sovie Union would nevertheless

appear to benefit suhstantially from thegreenhouse efrecl A warming of 8" couldadd as many as 40 days to the growing sea-son in i LUS S.R Uut a world with twiceas much CO) in the atmosphere also meansa continental interior that is considerablydrier, the Soviet Union would have tospend tens of billions on irrigation to takeadvantage of the longer growing season

How would the U S be affected com-mercially' Global warming would havestrange effects on the (ireat Lakes, the busi.est waterway in the world Using a comput-er model that projects an R" winter

11.1 4 orfTlriS I r i

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28

-A rtaaanglah' .Itaahhe sthlaaaaa I tat araaaancl%'r Iace si %at,.. ( alaa I ikt% Lttld be aw.'lic" II moaatta o'f .l . %% 8 S nalttl,iodayI lats allt.' gflkl eA,, TheI had nst,a, I1h1 ilet t fa gala %s iII .alsa t h cr. %a a.0a1t1paall's hIppt llt ' 1 ta 111.i 11 aaaat xga ias ara roair. grain aoit, avtd laaastaac %tll se e aa'arat.' 1l' Olt a$ Na .aaas | l at e r %atal IcaClt

wi all mata Ill daaaa freaghit'. can nalonport na i1gala alae 41.,k sysunas

P 1 RHAP fll ta higgest apriailaaaalanpt tt a~~ tr Ih 5 saaatatd t . an1 tita'

Mtdnight. asefe canit"at remel;Iit

er, prrtlicl I armng dr~maatrend St.lagerang wheat crop Iosse% deep.cred the (treat Dlcprcan and prarplcdthe baggesa i'pulition naagratan in Anar-kan hasors to hen Iampertatar(, r(te ;as ht-Ic as I and precapiatmon drop% I10'.'siadwestern crops All suffet Patl Wag-atoner, daretor of the ('onneracul Agracul-iural Lx N rnunt laaon in Ne w Iasien *see, a 2" to S', caU in ile 'a ield ofcommer-

iall) desarable i apter heatWestern I atanape mihi emipe the nasai-

er consequence% of global %armng be-c3se Itf% relatsely stnall landmass s closeto the sca and vs all rot undergo the santedegree of cornianentl drying as the L S.Canada. and the Sata te i raon What %allhappen to European temperatures is beingdebated Most scientists thank the GulfStream. fltang thousand, of males fromthe Caribbean. should continue to keepWestern Europe from free/ang to the con-sastenc) of Newfoundland. which as at thesame lataude But Wallace Broecker ofColumbia Umersity's Lamont-DoheryGeological Observatory an Palasade-. NewYork, warns that the greenhouse effectcould disturb the global circulation of theocean, an ways that cannot be predictedLike a teakettle that doesn't boil the mo-ment it's switched on, the earih's oceans.which range up to seven male-. deep. taketime to warm up It could take 20 to 60years before the oceans show the full ef-fect of global warmang

Research on the ffcts of global warm-ang in countrtes of the Thard World and theSouthern Hemisphere as sketchier Africamay benefit, at least an rainfall The raanbell across the equator wouldd r os, north-ward, according to research about to bepublished by S)ukuro Manabe, a climatemodeler at Princeton's Geoph)sical FluidIynamacs laboratory That's good newsfor the parched nations of the Sahel, an-eluding Chad, %udan, and Lihaopia, %hath

I hate atfl alre f tthl aaan lt % d cal itsldihln~ll ii t fL'loI 1111111 111~l L CIIFt.%i ll

lI p a lel- lIdtlt fill[h a 's ,tl l.aialjadehI .a lhlll 011t Iihih iN 0i1 N)l fcl .1114%aC

I csia tl on .I cIaVC. M0aail be h.lla'acid hay

1 t1OtalC *tI.011r 1 a ls Jd lolding* Not hen ai. nal t ahang(cs .I antal \,I-* atlas InO aroanicni Progi.im at %I P) report

Mlly dclarad last ycar irly sufl er;o u. hat ,ho:ald we do'

(lcarl) iahl air thlf s A c .an'i do litirail'l raih .irN.n dltos tlc atalt of iaadaifhilarllslsion, the' wa) a> c stan pillutanls hk,slltift daot idor 'oa-kcllcd 0leniitaIjl alLa-lirt ihsti ani systcns that siak top (O"emsmaart, add .ia much a. 8I0; to the aost

In a sense, getting up inthe morning adds tothe greenhouse effect.Everyone contributes.If everyone Is to blame,,no one is to blame.

of prodsucang cletracitl The mot efficientCO scrubbers are trees Like other plantsilae) absorb CO),. u"lne I to make foaod and

build (x)d But tree% are being felledaround the world at a clap of SO acres aminute. mostly in Brazil. Ot, est Africa, andIndonesia. according to L'N.P Redu.angdeforestation would help, but reforestation.proposed occaionally isn't a practical an,ssar The Oak Ridge National Laboratoryin Tennessee estimate% that to stop thegreenhouse effect cold would take 1.7 ba.lion acres of sycamore trees, which are es-pectally g(Fr at saaktng up C(0 That's anarea roughly the ste of Australia

Changing the max of fosl fuels canhelp Natural gas produces half the COI ofcoal and about Iwo-thard- that of oit forthe same amount of energy While at's un-lakely to happen, shifting completely tonatural gas from c"r I t petrtu4eni cou!Jextend by 20 to 30 years the time it takesfor atmospherc C(O to double from prean-dustral lea,

Some help should came from a 1987,reaty curbing production of chlorofluoro-carbons Released anto the atmosphere.these tynthelc chemicals., used in industr-al olvenl a id refrgerant,. eat away at the

.alttspherit aatiaaa lii-r that praits apiat-pic (fart dangerotna solaa r.adaamaan. whichflan arUse %kin tac i .faaal a.i.aaas If the

Iagaaracs ctompl. CI ( paiJuactmion atluldbe limited to 14M Ircl, begannang neot)car and grada.alh dop SO" by 199

Unfartunaaly tlre ('I-C agreement I%nat a nt ael faar .ttllng carhan dioxideIh that ,iea inflc iadusr) was the sourceof the pratblrm. there was satn cone Iblame Once iruaded t, strong satentaficcesadeatc. the thetmcal indusary agreed toIntalltlle poradatlion Uta ttv, fly caantrast noaaae aonlros flae praadut aan of cirhbon daoa-ade It s a reult aaf everyday processes oftafe In a sense, gellng up ia the morningadl io the greenhouse effect Turning onthat' athtalhm laght uses el.'cracat) general-Oad by faoasl fuels dravang io work burns gas-alare, even the building yott work in mayhat added to the praotlem because makingconcrete giest otf (Oa f er.one contrab-aaac the gretnhou e effect If eer)one *sto lanic, no one is taa blane

I nerg) canserataan %ould reduce car-Nan daoaid enamaion at the srurcc butwoulJ b' 1U.914 it a enforce Most alternataveenergy sources seem impractical. for themoment Wind, geothermal, and solar ener-g) hae ao far been casualates of low oilprices So hate synfuel. which have theadded daadtanaage of producing as muchcarbon dioxide as fosal fuels Nuclear ener.gy. despac well-deserved public concernabo-)ut its safety, may deserve a second lookbecause it produce, no carbon dioxide

A LL THESF strategies seek to buytame Ohs orasls at as bearer to ad-

just to the greenhouse effect over200 )ears rather than 50. But an

all-out international effort to reduce CO,emssaians seems sure to ht two majorsnags Countries that stand to benefit fromglobal warming aren' likely to bring muchenthusiasm to averting it. And those thatstand to lose hae trouble viewing thas das-tant. somewhat speculative threat with theurgency required to call forth expensiveand di rupase counermeasures,

If nations don't take action. Mack Kellyof the Unisefsil) of Fast Anglia suggestswhat businesses might do "The winnersfrom global warming." he says. "are goingIo be those people who thank ahead of tameand plan The losers are going to be thosewho respond only when the cnss arrives.on Ihe spur of Ihe moment - For hose whowant to come out winners. now is not toosoon to start thanking a

)ULY 4. 191a FORTUNE 107

29

LOOKING AHEAD

WHAT MAKES THE WEATHER SO HARD TO FORECAST

U Holt do climate scientist% knowthe greenhouse effect will bringabout the woes that they predict? Theydon't know to a total certainty. Whatthey do know is based on half a dozenhigh-powered computer simulation pro-grams. called general circulation models.in North America and Europe. Re-searchers feed in equations based on thelaws of physics, along with asumptionsabout clouds. st ice. ocean currents.soil moisture, atmospheric convection.and emission of heat from the ground

More complicated things happen inthe heavens and on earth. however, thanare dreamt of in the equations of scien-ttsts Even using the best supercom-pulers. none of the models is so goodthat it cart start with known weatherconditions at a given point in the pastand reproduce precisely what has hap-pened since. To make the calculationsmanageable even by computers, most ofthe models suppose either that theoceans are a shallow, motionless swampor that they don't extt at all. Despitethat oversimplification, an especially so-

phisticated computer model at the Na-tional Center for Atmospheric Research(NCAR) in Boulder, Colorado. requires1.5 trillion calculations to advance itspredictions a single day.

One basic problem is called grid reso-lution. Climatologists divide the worldinto a grid. Most use a grid with squaresthe size of France. The grid definesFrance as a single set of numbers, failingto distinguish the cool, rainy north fromthe sunny, drier south. In his 1987 bookChaos. James Gleick. a New YorkTimes reporter, imagined a world cov-ered with a vast jungle gym of sensorsspaced a foot apart and nsig 35 miles tothe top of the atmosphere. Each sensormeasures with great precision tempera-ture. pressure, humidity, and every othermeteorological variable. An infinitelypowerful computer processes all thedata. This seemingly perfect monitoringsystem still could no( predict exactly theweather next month in Atlanta.

The reason: The computer would notdetect microflucluattons that took placein between the sensors. Errors multiply

so quickly that within hours the realityof weather diverges from its predictedcourse. In effect, you can never haveenough grid squares to forecast weatheraccurately. Tiny variations matter. TheButterfly Effect. known technically as"sensitive dependence on initial condi-tions." fees its name from the thoughtthat a butterfly flapping it% wings todayin Nagasaki could conceivably influencestorms next month in New York.

While most scientists agree that thegreenhouse effect is coming, there aren'tenough data yet to say with absoluteconviction what its consequences willbe. Certainties in science are a long timein the making. In a proestion wheretentative conclusions require decades'worih of data. one swallow does notmake a summer. As recently as the1970s some chmatologisus were worry-tng about global coolinS, because worldtemperatures had peaked in the 1940sand Eten declined into the 1970s. AirpW:utants such as volcanic and man-made dust may have blocked enoughsunlight to lower global temperatures.

TMs compter mo del sewan pslbe rises In wint r tilsaeatwes., in Celsku If CO* b the ak deIeos frem the ItMh-eeetrwy inveL

106I FORTUNE AILY4 1998

89-338 0 - 88 - 2

30

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I IiA1 I III - IIII % I' Ii.iiii

The Greenhouse Effect? Real Enough.A fierce drought is shriveling crops from Texas

to North Dakota and has shrunk the Mississippi toits lowest levels on record. Dry years are part of na.ture's cycle St:ll. it's time to take seriously anotherpossible influence - the warming of the atmos-phere by waste gases from a century of industrialactivity. Whether or not the feared greenhouse ef-fect is real, there are several preventive measuresworth taking in their own right.

The greenhouse theory holds that certain wastegases let in sunlight but trap heat. which otherwisewould escape into space. Carbon dioxide has beensiea4ily building up through the burning of coal andoil - and because forests, which absorb the gas, arefast being destroyed. There is noclear proof that the gases haveyet begun to warm the atmos- Sunphere. But there's circumstan.trial evidence, and some expertsthink it is getting stronger.

For example, four of thelast eight years - 1980, 1981,1983 and 1987 - have been thewarmest since measurementsof global surface temperaturesbegan a century ago, and 1988may be another record hot year.Still, there have been hot spellsbefore, followed by a cooling.

According to computersimulations of the world's cli-mate. there should be more rainin a greenhouse-heated globe. The rain falls In dif-ferent places: more at the poles aid the equator,less in the mid-latitudes. The drought In the MiddleWest falls in with these projections. JBut it stops farshort of proving that the greenhouPe effect hasbegun. "As far as we can tell, this it a sough sum-mer well within the normal range of variability,"says Donald Gilman, the Weather Service's long.range forecaster.

That's the nub of the problem: It's hard to iden-lily a small, gradual sign of global warming amidwide natural fluctuations In climate. Even over thelong term, the evidence Is merely Indicative. Tbe

world has warmed half a degree centigrade overthe last century. But the warming is less than somecomputer models predict, forcing defenders of thegreenhouse theory to argue that the extra hem isdisappearing into the oceans.

With the greenhouse effect still uncertain, whytake preventive steps, especially since the mainone, burning less coal, would be enormously expen-sive? One answer is that it it may take years to ac-quire positive proof of greenhouse-induced climatechange, and the longer society waits, the larger awarming it will have to adapt to if the greenhousetheory turns out to be valid, Even a small warmingcould produce violent changes in climate. At worst,

the Gulf Stream might shiftcourse, failing to warm Europe.Sea level could rise 20 feet if theWest Antarctic Ice Cap melts,flooding coastal cities from New

a1 York to New OrleansSeveral measures to slow

-Air and the greenhouse warming areWaste worth taking for other reasons:Gases 0 Cut production of freQns,

chemicals used as solvents andrefrigerants Important green-house gases, they destroy thelife-protecting ozone layer.

0 Protect tropical forests,Earth which not only absorb carbon

dioxide but also nourish a richvariety of animal and plant life.

o Encourage conservation of energy and use ofnatural gas, which produces half as much carbondioxide as does coal.

o Develop cheaper, safer nuclear power; nu-clear plants produce no carbon dioxide or acid rain.

Many climatologists expect that the green.house theory will eventually prove true, but fear toIssue alarmist warnings ahead of time. Their cau-tion Is justified. But there's an ample case for tak.ing these initial preventive measures when the costof such Insurance Is so low and the discomforts ofabrupt climate change, as the drought demon-strates, so high.

I

31

Senator WIRTH. Senator Ford.Senator FORD. No. Thank you, Mr. Chairman. I look forward to

being educated.Senator WXRTH. Thank you.Senator Conrad.

STATEMENT OF HON. KENT CONRAD, U.S. SENATOR FROM NORTHDAKOTA

Senator CONRAD. Well, I would just briefly say, Mr. Chairman,that I come from a state that is being devastated by the currentdrought. I was just there this weekend, and the pastures lookedlike a moonscape. The wheat crop is absolutely devastated. And wehave been through this before.

In the 1930's we had a similar drought, and I will be very inter-ested in hearing what evidence there might be to indicate that thedrought of the 1980's is different than the drought of the 1930's. Ithink that really is the central question before us, to establish therecord and the case for an increase over time of temperature andwhat the long-term effects might be. And that's what I will be look-ing for in this hearing.

And I want to thank both Senator Wirth for his leadership onthis issue and the Chairman of the full committee for his supportof having a hearing like this. It is terribly important to an arealike mine that is so commodity dependent.

Senator WIRTH. Thank you, Senator Conrad.We are joined today and in this effort by Senator Max Baucus,

who along with many members of the Committee on Environmentand Public Works, has had a great concern about this and relatedkinds of issues. Max, delighted to have you here.

STATEMENT OF HON. MAX BAUCUS, U.S. SENATOR FROMMONTANA

Senator BAucus. Thank you, Mr. Chairman.Mr. Chairman, I commend you and Senator Johnston for holding

these hearings. The more hearings we have in more committeesand not get hung up on committee jurisdiction, the better off we'regoing to be and the more likely it is we will find a meaningful solu-tion to the problem.

I sense that we are experiencing a major shift. It's a like of shiftof tectonic plates. Our country not too many years ago was con-cerned basically with economic and environmental problems withinthe borders of our country. And a few years ago we began to realizethat we are economically interdependent with other countries,other peoples, other industries around the world, and our fate isvery much tied up with the economic fate of people in other coun-tries.

I think there is another shift now, and it's an environmental tec-tonic plate shift. That is, we realize as Americans that our environ-mental problems in America-the focus must be not only on ourown country within the confines of our borders, but also the envi-ronmental problems worldwide. The world is getting smaller. Weall are in this boat together. And I think that this hearing andothers like it help that awareness.

0

32

In addition, Mr. Chairman, I have a sense of deja vu. It wasn'ttoo long ago that scientists predicted with their models the deple-tion of ozone in the stratosphere. We looked at-th@"m els inother committees, and what we found is that the models were notaccurate, but they were timid. They did not really predict thedegree to which stratospheric ozone is depleting. They did not pre-dict the degree to which the Antarctic hole has developed. They didnot predict the degree to which ozone depletion is not in the strato-sphere over the Antarctic, but also now over northern hemi-spheres.

So, I suggest that if we err-hereTwe-do err on the side of action. Ithink that the scientific models are becoming more sophisticated.They are becoming more accurate. And the old question of, well, dowe have enough information, let's take some more time, I think itbecoming more clear not only because of what has happened withthe depletion of stratospheric ozone, but because the models andscientific analysis is becoming more sophisticated and more accu-rate that we can be more assured and more confident of movingforward more quickly.

I've had a chance to briefly look at Mr. Jim Hansen's testimony,and I think that his testimony is quite graphic in predicting thatthis is not just a chance occurrence, that statistically the increasein global temperature is not only in our country, but in Moscow inthe Soviet Union and other similar latitudes. It is beyond chance.It is more certain as the predictions are greater that, in fact, theearth is warming up to the degree that the models tend to predict.

The answers I think are to inventory our carbon dioxide andother greenhouse gas sources. We have to get a better idea of whatthe major sources are of the various greenhouse gases. Certainlyone source is the automobile industry, automobiles. Certainly acause of the problem is our energy inefficiency in our country. Weare one of the most energy inefficient countries in the world. Andwe' re going to have to bite the bullet frankly, with the automobileindustry and other major industries to force ourselves to be moreefficient and reduce greenhouse gas emissions. CFC reductionshelp. That is only a small part of the problem. There are the meth-anes. There are carbon dioxide and other gases that have to be ad-dressed.

And I very much commend you, Mr. Chairman, for taking thisaction.

[The prepared statement of Senator Baucus follows:]

33

STATEMENT BY SENATOR MAX BAUCUSON GLOBAL WARMING

I am delighted to have the opportunity this afternoon to testify beforethe Subcommittee in this hearing on global climate change. The greenhouseeffect, global climate change, and stratospheric ozone depletion areinterrelated environmental problems which pose the greatest environmentalchallenge that our planet will face in the next decade.

I commend you, Mr. Chairman, for holding this hearing and for yourcontinued interest in the greenhouse effect and global climate change. Itis an interest we share. Since December of 1985, members of the Committeeon Environment and Public Works have held nine days of hearings on theseissues.

Testimony presented at those hearings by leading scientists painted adisturbing picture. Like those who believe the stock market crash ofOctober was a warning on the economy, we must'ask ourselves if the droughtwe are facing is nature's warning to mankind to clean up its act.

Dr. Wallace Broecker described the problem we face this way:

"The inhabitants of planet Earth are quietly conductlnq a giganticenvironmental experiment. So vast and so sweeping will be its impact that,were it brought before any responsible council for approval, it would befirmly rejected as having potentially dangerous consequences. Yet theexperiment goes on with no significant interference from any jurisdiction ornation."

The experiment in question is the so-called greenhouse effect - thegradual warming of our atmosphere caused by an overload of carbon dioxideand other trace gases.

I like to think greenhouses produce useful things for mankind.However, a global greenhouse will produce very little except more drought,famine, and economic and social upheaval.

The warning signs are clear. Carbon dioxide concentrations haveincreased by 25% since 1900. Methane concentrations have risen about 100%in the last 150 years.

In the last 35 years alone there has been a 30 to 40% increase. Thetwo principal fluorocarbons implicated in the greenhouse effect - CFC-11 andCFC-12 - are growing at a rate of 5% per year. Nitrous oxide concentrationsare growing at two- tenths of one percent per year. Tropospheric ozone isincreasing by 1% per year in the Northern Hemisphere. Elsewhere on theglobe, tropospheric ozone trends are not well known.

The excess radiation absorbed by these greenhouse gases provides theenergy to drive the climate system and arter global and regional climate

r

34

Page 2

patterns, atmospheric circulation patterns, and oceanic circulationpatterns.

The projected increases in the greenhouse gases are predicted to causeunprecedented global and regional climate changes.

Temperature will increase. Current models predict an increase in theaverage global temperature of 1.5 to 4.5 degrees centigrade by the year2030. That is an increase of about 3 to 9 degrees Fahrenheit in only 40years.

These "global average temperatures" do not accurately reflect localtemperature changes. An average temperature rise of only three degreescentigrade could mean an increase of more than ten degrees centigrade athigh altitudes in some seasons.

Precipitation will increase. A warmer climate will evaporate moremoisture which will ultimately fall to the ground as precipitation. Hence,overall, the globe will be wetter and more humid.

Precipitation patterns will change, possibly upsetting agriculturalactivities worldwide.

A warmer atmosphere will melt the sea ice in the polar regions. Sincethe underlying ocean is much darker than the sea ice, melting of the icewill lead to increased solar absorption. This absorption will act as a feed-back mechanism for further ocean and atmosphere circulation changes.

Current models predict that climate change will lead to the dessicationof the continents in the mid-latitudes. In summer, the Great Plains of theUnited States, Central Europe, and parts of the Soviet Union could ex-perience Dust Bowl conditionsW

Sea level could rise from one to four feet, inundating our coastlinesand contaminating drinking water supplies with salt water.

Dcean currents could shift, changing the climate of many areas anddisrupting fisheries.

The frequency of tropical storms is predicted to increase, as isincreased monsoonal rain in the tropics.

With the "greenhouse effect", we are not talking about short-termchanges. We are talking about permanent and perhaps ongoing change for someindefinite period into the future.

We are talking about a situation where mankind has finally wrestledcontrol of this planet from Nature. It is a responsibility we are illequipped to assume.

We are already committed to some of these changes. Past emissions ofgreenhouse gases have already camitted Earth to warm by 0.5 to 1.5 degreescentigrade over the pre-industrial era. If emissions continue along their

35

Page 3

present track, we will have committed Earth to a warming of 1.5 to 4.5degrees centigrade by 2030.

These changes may be occurring now. It is expected that within thenext few years, we shall actually be able to measure these changes.

The nation is in the midst of one of the most devastating droughtssince the dust bowl days of the 30's. Drought is occurring from Californiato Texas to Georgia to Iowa to Montana.

Last week I accompanied a group of Senators to view the problems posedby drought in the Northern Great Plains. I can tell you things are prettygrim in Montana.

Our reservoirs did not fill this Spring. Estimates of wheat productionshow yields are down as much as fifty percent. In a-short period of time,without rain, we can expect major problems with grasshoppers ravaging whatcrops remain.

Over the past few years, the West has experienced devastating forestfires. The fire season started over a month earlier than usual in SouthernCalifornia.

The current drought is responsible for real economic suffering.

If the climate has changed due to greenhouse gases, we will be forcedto live with these changes and to adapt.

As policy-makers, we must find ways to minimize economic dislocationson the one hand. On the other hand, we must minimize the rate of climatechange to one we can adapt to.

The fundamental question is, should we wait until the problem isactually known for sure, or take steps to address the problem now?

I believe we need to move now. We are talking about a problem that hasbeen building up for at least the last century. Each day we fail to setneeded policies in motion, the potential for failure increases.

The fundamental issue that we face is to develop a strategy to dealwith global climate change. The next decade should be a period of intensescientific research designed to provide answers to the greenhouse problem,policy exploration, and adoption of appropriate preventative and adaptivecontrol measures.

There are things which we can do now. Reductions in the use of coaland gas, and energy conservation measures will reduce the concentrations ofgreenhouse gases.

Reductions in the emissions of chlorofluorocarbons will help to slowthe rate of climate change, and will help to preserve the Earth's stratos-pheric ozone shield. Both Senator Chafee and I have introduced legislation

86

Page 4

which would eventually phase-out the use of harmful man-made CFC's which arecurrently destroying the Earth's protective ozone layer.

The problem of global warming and ozone depletion have reached a stagethat requires a broader and more institutional commitment to internationaldialogue. The focus for this effort should be the United NationsEnvironment Program (UNEP).

We need to urge UNEP to step forward with a comprehensive report onglobal climate change, detailing the seriousness of the problem for allnations of the world. This effort could play a pivotal role in developingan international committment to address this problem.

Finally we need to focus the efforts of the scientific community onimproving our understanding of the interrelated problems of the greenhouseeffect, global climate change, and stratospheric ozone depletion. We needto set the "Greenhouse Effect" as the number one priority of theInternational Geosphere/Biosphere Program, and set priorities for ourresearch efforts.

We are at a point in time where we must examine the policy options now.Some changes in climate as we know it are already in the bank. Themagnitude and timing of other changes are still speculative. We must ensurethat the scientific research which is started today is designed to improvethe information base for policy options.

I think it would be useful to spell out some of the means that willhave to be considered in order to limit climate change and thus stabilize orreduce the concentration of greenhouse gases in the atmosphere.

We know, for example, that we must reduce the emission of carbondioxide which makes up about one half of the greenhouse emissions. Whatmethod should the Secretary of State and the Administrator of EPA considerin this regard? Recent Senate testimony has suggested a number of policieswhich will have to be considered in order for the United States to reduceits carbon dioxide emissions which account for almost a quarter of theglobal total.

Carbon dioxide emissions are tied to the types and amounts of fossilfuels which we use in our economy. Therefore, controlling carbon dioxideemissions will require changes in the way we manage our energy use in thefuture. Consideration should be given to improvement in energy end-useefficiency, such as lighting, and across the board in new appliances. Theefficiency of supply energy technology can also be improved

New gas-fueled power plant technologies appear to improve efficiencysubstantially. A vast improvement of auto efficiency standards for carssold in the United States must be considered in order to lower the use ofgasoline.

Pricing initiatives must be considered in order to reflect the"externalities" in the price of fossil fuels. A number of experts have

37

Page 5

suggested the establishment of a carbon dioxide tax in order to reflect thedamage to our climate reflected in the price of energy.

Fuel switching must also be considered since some fuels produce muchless carbon dioxide per BTU than others. Coal, for example, produces twicethe carbon dioxide per BTU as gas.

Stopping the destruction of tropical forests - a significant carbondioxide sink - is an important step. Consideration should also be given toreforestation.

We know also that the complete elimination of CFCs would provide amajor greenhouse benefit. That too should be considered.

We know that improving the controls on carbon monoxide might controlthe buildup of methane.

* Wethroughbuildupbecause

should consider reexamining whether nitrous oxides can be controlledair pollution control technologies. We may need to control theof tropospheric ozone not just locally, but also on a national basisozone in the troposphere is also a greenhouse gas.

Dealing with the greenhouse problem is a daunting task. We must notwait; we must begin now. We are already too late. I think the list ofresponses I mentioned previously should help us get started in formulatingand initiating a response.

There is an urgent need to move rapidlypolicies to control and mitigate the impactsdomestically and internationally.

I lookprepared todiscussionspolicies to

towards the development ofof global climate change, both

forward to working with you to ensure that the United States ismeet the threat of global climate change. I am hopeful that yourtoday will begin to focus our attention on the development ofcombat global climate change.

I appreciate the opportunity to appear before you today to discuss themajor environmental problem facing our planet, global climate change.

38

Senator WIRTH. Thank you, Senator Baucus.Senator Bumpers.

STATEMENT OF HON. DALE BUMPERS, U.S. SENATOR FROMARKANSAS

Senator BUMPERS. Well, Mr. Chairman, I won't burden our timeconstraints here except to say I welcome all of our witnesses heretoday. Bill Moomaw, who was a congressional science fellow withme when, Bill? In 1976?

Dr. MOOMAW. Yes.Senator BUMPERS. In 1976, and is the person that is responsible

for my deep and abiding interest in both the ozone problem andthe greenhouse theory of Dr. Ramanathan, all of which those of uswho were born to rule knew back in 1976 was a problem.

But we couldn't get one camera-I see we have three camerashere today-for the hearings we held back then. We had nine hear-ings and had the best atmospheric scientists in the country. Everyone of them told us that we were possibly facing a cataclysm inboth of these areas.

And now we know that the four warmest years in the last 130years-the four hottest years of the last 130 years-'have occurredsince 1980. Now, that may be pure coincidence, but my'belief isthat we cannot afford to assume that. On the contrary, we have toassume the very opposite that we may be facing a cataclysm in thefuture, much of which is already in place and irreversible. But thatdoesn't excuse us from the obligation to take very dramatic action.None of us is quite action to take yet.

And Dr. Hansen is going to testify today to what I just said plussome additional things that ought to be cause for headlines inevery newspaper in America tomorrow morning because, after all,we're going to have to have a lot of political suprt for this.Nobody wants to take on the automobile industry. Nobody wants totake on any of the industries that produce the things that wethrow up into the atmosphere. They don't want that stopped, andthat's understandable. But what you have are all these competingeconomic interests pitted against our very survival.

Thank you, Mr. Chairman.Senator WIRTH. Thank you very much , Senator Bumpers.Before we begin, there are about eight or nine seats down here.

Maybe those of you who are-standing up behind the table over heremight want to come down. There is no point in standing upthrough this on a hot day or any day.

Thank you all. I'm delighted to have with us such a distin-guished group of witnesses.

What I would like to do, if we might, today is to start with Dr.James Hansen, the Director of the Goddard Institute for SpaceStudies, whose *climate data have demonstrated what SenatorBumpers was pointing out, the four warmest years during thisdecade, and who I believe has a number of other interesting revela-tions from recent research that might set the scene for this after-noon 's discussion. If we could then move to Dr. Michael Oppen-heimer, Senior Scientist with the Environmental Defense Fund;and Dr. George Woodwell, Director of the Woods Hole Research

39

Center in Woods Hole; Dr. Manabe from NOAA, Geophysical FluidDynamics Laboratory in Princeton; Dr. Dudek, a senior economistwith the EDF; and finally Dr. William Moomaw, Senior Associateof WRI, World Resources Institute.

All of your statements will be included in full in the record, andwe would ask you to summarize in the way that you think wouldbe most beneficial. And after you have all had a chance to testify,we will then go to questions and discussions with the members ofthe Senate. Sovgentlemen, thank you verymuch for being here.Dr. Hansen, if you would start us off, we'd ipprciate it.

STATEMENT OF DR. JAMES HANSEN, DIRECTOR, NASA GODDARDINSTITUTE FOR SPACE STUDIES

Dr. HANSEN. Mr. Chairman and committee members, thank youfor the opportunity to present the results of my research on thegreenhouse effect which has been carried out with my colleagues atthe NASA Goddard Institute for Space Studies.

I would like to draw three main conclusions. Number one, theearth is warmer in 1988 than at any time in the history of instru-mental measurements. NUjnber two, the global warming is nowlarge enough that we can ascribe with a high degree of confidencea cause and effect relationship to the greenhouse effect. Andnumber three, our computer climate simulations indicate that thegreenhouse effect is already large enough to begin to effect theprobability of extreme events such as summer heat waves.

My first viewgraph, which I would like to ask Suki to put up ifhe would, shows the global temperature over the period of instru-mental records which is about 100 years. The present temperatureis the highest in the period of record. The rate of warming in thepast 25 years, as you can see on the right, is the highest on record.The four warmest years, as the Senator mentioned, have all beenin the 1980s. And 1988 so far is so much warmer than 1987, thatbarring a remarkable and improbable cooling, 1988 will be thewarmest year on the record.

Now let me turn to my second point which is causal associationof the .greenhouse effect and the global warming. Causal associa-tion requires first that the warming be larger than natural climatevariability and, second, that the magnitude and nature of thewarming be consistent with the greenhouse mechanism. Thesepoints are both addressed on my second viewgraph. The observedwarming during the past 30 years, which is the period when wehave accurate measurements of atmospheric composition, is shownby the heavy black line in this graph. The warming is almost 0.4degrees Centigrade by-1987 relative to climatology, which is de-fied as the 30 year mean, 1950 to 1980 and, in fact, the warming ismore than 0.4 degrees Centigrade in 1988. The probability of achance warming of that magnitude is about 1 percent. So, with 99percent confidence we can state that the warming during this timeperiod is a real warming trend.

The other curves in this figure are the results of global climatemodel calculations for three scenarios of atmospheric trace gasgrowth. We have considered several scenarios because there areuncertainties in the exact trace gas growth in the past and espe-

40

cially in the future. We have considered cases rani.g from b-usi-ness as usual, which is scenario A, to draconian emission cuts, sce-nario C, which would totally eliminate net trace gas growth byyear 2000.

The main t to be made here is that the expected globalwarming is of the same magnitude as the observed warming. Sincethere is only a 1 percent chance of an accidental warming of thismagnitude, the agreement with the expected greenhouse effect is ofconsiderable significance. Moreover, if you look at the next level ofdetail in the global temperature change, there are clear sins ofthe greenhouse effect. Observational data suggests a cooling in thestratosphere while the ground is warming. The data suggest some-what more warming over land and sea ice regions than over openocean, more warming at high latitudes than at low latitudes, andmore warming in the winter than in the summer. In all of thesecases, the signal is at best just beginning to emerge, and we needmore data. S~me of these details, such as the northern hemispherehigh latitude temperature trends, do not look exactly like thegreenhouse effect, but that is expected. There are certainly otherclimate change factors involved in addition to the greenhouseeffect.

Altogether the evidence that the earth is warming by an amountwhich is too large to be a chance fluctuation and the similarity ofthe warming to that expected from the greenhouse effect repre-sents a very strong case. In my opinion, that the greenhouse effecthas been detected, and it is changing our climate now.

Then my third point. Finally, I would like to address the ques-tion of whether the greenhouse effect is already large enough toaffect the probability of extreme events, such as summer heatwaves. As shown in my next viewgraph, we have used the tempera-ture changes computed in our global climate model to estimate theimpact of the greenhouse effect on the frequency of hot summers inWashington, D.C. and Omaha, Nebraska. A hot summer is definedas the hottest one-third of the summers in the 1950 to 1980 period,which is the period the Weather Bureau uses for defining climatol-ogy. So, in that period the probability of having a hot summer was33 percent, but by the 1990s, you can see that the greenhouse effecthas increased the probability of a hot summer to somewhere be-tween 55 and 70 percent in Washington according to our climatemodel simulations. In the late 1980s, the probability of a hotsummer would be somewhat less than that. You can interpolate toa value of something like 40 to 60 percent.

I believe that this change in the frequency of hot summers islarge enough to be noticeable to the average person. So, we havealready reached a point that the ,reenhouse effect is important. Itmay also have important implications other than for creature com-fort.

My last viewgraph shows global maps of temperature anomaliesfor a particular month, July, for several different years between1986 and 2029, as computed with our global climate model for theintermediate trace gas scenario B. As shown by the graphs on theleft where yellow and red colors represent areas that are warmerthan climatology and blue areas represent areas that are colderthan climatology, at the present time in the 1980s the greenhouse

41

warming is smaller than the natural variability of the local tem-perature. So, in any given month, there is almost as much areathat is cooler than normal as there is area warmer than normal. Afew decades in the future, as shown on the right, it is warm almosteverywhere.

However, the point that I would like to make is that in the late1980's and in the 1990's we notice a clear tendency in our model forgreater than average warming in the southeast United States andthe midwest. In our model this result seems to arise because theAtlantic Ocean off the coast of the United States warms moreslowly than the land. This leads to high pressure along the eastcoast and circulation of warm air north into the midwest or thesoutheast. There is only a tendency for this phenomenon. It is cer-tainly not going to happen every year, and climate models are cer-tainly an imperfect tool at this time. However, we conclude thatthere is evidence that the greenhouse effect increases - the likeli-hood of heat wave drought situations in the southeast and midwestUnited Stats even though we cannot blame a specific drought onthe greenhouse effect.

Therefore, I believe that it is not a good idea to use the period1950 to 1980 for which climatology is normally defined as an indi-cation of how frequently droughts will occur in the future. If ourmodel is approximately correct, such situations may be morecommon in the next 10 to 15 years than they were in the period1950 to 1980.

Finally, I would like to stress that there is a need for improvingthese global climate models, and there is a need for global observa-tions if we're going to obtain a full understanding of these phenom-ena.

That concludes my statement, and I'd be glad to answer ques-tions if you'd like.

[The prepared statement of Dr. Hansen follows:]

42

THE GREENHOUSE EFFECT: IMPACTS ON CURRENT GLOBAL

TEMPERATURE AND REGIONAL HEAT WAVES

STATEMENT OF

James E. HansenNASA Goddard Institute for Space Studies

2880 Broadway. New York, N.Y. 10025

PRESENTED TO:

United States Senate

Couittee on Energy and Natural Resources

June 23, 1988

43

2

PREFACE

This statement is based largely on recent studies carried out with mycolleagues S. Lebedeff, D. Rind, I. Fung, A. Lacis, R. Ruedy, C. Russell andP. Stone at the NASA Goddard Institute for Space Studies.

My principal conclusions are: (1) the earth is warmer in 1988 than at anytime in the history of instrumental measurements, (2) the global warming is nowsufficiently large that we can ascribe with a high degree of confidence a causeand effect relationship to the greenhouse effect, and (3) in our computer climatesimulations the greenhouse effect nov is already large enough to begin to affectthe probability of occurrence of extreme events such as summer heat waves; themodel results imply that heat wave/drought occurrences in the Southeast andMidwest Unit d States may be more frequent in the next decade then inclimatologgal (1950-1980) statistics.

1. Currant global tam-eatures

Present global temperatures are the highest in the period of instrumentalrecords, as shown in Fig. 1. The rate of global warming in the past two decadesis higher than at any earlier time in the record. The four warmest years in thepast century all have occurred in the 1980's.

The global temperature in 1988 up to June 1 is substantially warmer than thelike period in any previous year in the record. This is illustrated in Fig. 2,which showt seasonal temperature anomalies' for the past few decades. The mostrecent two seasons (Dec. -Jan.-Feb. and Mar.-Apr.-May, 1988) are the warmest inthe entire record. The first five months of 1988 are so warm globally that weconclude that 1988 will be the warmest year on record unless there is aremarkable, improbable cooling in the remainder of the year.

2. Relationship of global varying aEd greenhouse effect

Causal association of current global warning with the greenhouse effectrequires determination that (1) the warning is larger than natural climatevariability, and (2) the magnitude and nature of the warning is consistent withthe greenhouse warning mechanism. Both of these issues are addressed -"quantitatively in Fig. 3, which compares recent observed global temperaturechange with climate model simulations of temperature changes expected to resultfrom the greenhouse effect.

The present observed global warming is close to 0.4"C, relative to'climatoligy', which is defined as the thirty year (1951-1980) mean. A warmingof O.4"C is thrq times larger than the standard deviation of annual meantemperatures in the 30-year climatology. The standard deviation of 0.13"C is atypical amount by which the global temperature fluctuates annually about its 30 -year mean; the probability of a chance warning of three standard deviations isabout It. Thus we can state with about 990 confidence that current temperaturesrepresent a real warning trend rather than a chance fluctuation over the 30 yearperiod.

44

We have made computer simulations of the greenhouse effect for the periodsince 1958, when atmospheric CO2 began to Oe measured accurately. A range oftrace gas scenarios is considered so as to-account for moderate uncertainties intrace gas histories and larger uncertainties in fut-uts Lace 555 grawth raret:The nature of the numerical climate model used for these simulations is describedin attachment A (reference 1). There are major uncertainties in the model, whicharise especially from assumptions about (1) global climate sensitivity and (2)heat uptake and transport by the ocean, as discussed in attachment A. However,the magnitude of temperature changes computed with our climate model in varioustest cases is generally consistent with a body of empirical evidence (reference2) and with sensitivities of other climate models (reference 1).

The global temperature change simulated by the model yields a warming overthe past 30 years similar in magnitude to the observed warming (Fig. 3). In boththe observations and model the warming is close to 0.4'C by 1987, which is the99% confidence level.

It is important to compare the spatial distribution of observed temperaturechanges with computer model simulations of the greenhouse effect, and also tosearch for other global change related to the greenhouse effect, for example,changes in ocean heat cont sea ica coverage. As yet, it is difficult toobtain definitive conclusions from such comparisons, in part because the naturalvariability of regional temperatures is much larger than that of global meantemperature. However, the climate model simulations indicate that certain grosscharacteristics of the greenhouse warming should begin to appear soon, forexample, somewhat greater warming at high latitudes than at low latitudes,greater warming over continents than over oceans, and cooling in the stratospherewhile the troposphere warms. Indeed, observations contain evidence for all thesecharacteristics, but much more study and improved records are needed to establishthe significance of trends and to use the spatial information to understandbetter the greenhouse effect. Analyses must account for the fact that there areclimate change mechanisms at work, besides the greenhouse effect; other anthropo-genic effects, such as changes in surface albedo and troposphericaerosols. arelikely to be especially important in the Northern Hemisphere.

We can also examine the greenhouse warming over the full period for whichglobal temperature change has been measured, which is approximately the past 100years. On such a longer period the natural variability of global temperature islarger; the standard deviation of global temperature for the past century is0.2"C. The observed warming over the past century is about 0.6-0.7"C. Simulatedgreenhouse warming for the past century is in the range 0.5"-1.0"C, dependingupon various modeling assumptions (e.g., reference 2). Thus,.,slthough there aregreater uncertainties about climate forcints in the past century than in the past30years, the observed and simulated greenhouse warnings are consistent on bothof these time scales.

Conclusion. Global warming has reached a level such that we can ascribewith a high degree of confidence a cause and effect relationship between thegreenhouse effect and the observed warming. Certainly further study of thisissue must be made. The detection of a global greenhouse signal represents onlya first step in analysis of the phenomenon. g r o

45

4

3. Greenhouse inacts on summer heat waves

Global climate models are not yet sufficiently realistic to provide reliablepredictions of the impact of greenhouse warning on detailed regional climatepatterns. However, it is useful to make initial studies with st&te-of-the-artclimate models; the results can be examined to sea whether there are regionalclimate change predictions which can be related to plausible physical mechanisms.At the very least, such studies help focus the work needed to develop improvedclimate models and to analyze observed climate change.

One predicted regional climate change which has emerged in such climatemodel studies of the greenhouse effect is a tendency for mid-latitude continentaldrying in the summer (references 3,4,5). Dr. Nanabe will address this importantissue in his testimony today. Most of these studies have been for the case ofdoubled atmospheric CO2 , a condition which may occur by the middle of next century.

Our studies during the past several years at the Goddard Institute for SpaceStudies have focused on the expected transient climate'change during the noxt fewdecades, as described in the attachment to my testimony.. Typical results fromour simulation for trace gas scenario B are illustrated in Fig. 4, which showscomputed July temperature anomalies in several years between 1986 and 2029. Inthe 1980's the global warming is small compared to the natural variability oflocal monthly mean temperatures; thus the area with cool temperatures in a givenJuly is almost as great as the area with warm temperatures. However, withinabout a decade the area with above normal temperatures becomes much larger thanthe area with cooler temperatures.

The specific temperature patterns for any given month and year should not beviewed as predictions for that specific time, because they depend upon unpre-dictable weather fluctuations. However, characteristics which tend to repeatwarrant further study, especially if they occur for different trace gasscenarios. We find a tendency in our simulations of the late 1980's and the1990's for greater than average warning in the Southeast and Midwest UnitedStates, as illustrated in Attachment A and in Fig. 4. These areas of hightemperature are usually accompanied by below normal precipitation.

Examination of the changes in sea level pressure and atmospheric winds inthe model suggests that the tendency for larger than normal warming in theMidwest and Southeast is related to the ocean's response time; the relativelyslow warning of surface waters in the mid-Atlantic off the Eastern United Statesand in the Pacific off California tends to increase sea level pressure in thoseocean regions and this in turn tends to cause more southerly winds in the easternUnited States and stre northerly winds ifi the western United States. However,the tendency is too small to be apparent every year; in some years in the 1990'sthe eastern United States is cooler than climatology (the control run mean).

Conclusion. It is not possible to blame a specific heatwave/drought on thegreenhouse effect. However, there is evidence that the greenhouse effectincreases the likelihood of such events; our climate model simulations for thelate 1980's-and the 1990's indicate a tendency for an increase of heatwave/drought situations in the Southeast and Midwest United States. We note that thecorrelations between climate models and observed temperatures are often very poorat subcontinental scales, particularly during Northern Hemispher4 summer(reference 7). Thus improved understanding of these phenomena depends upon the

46

development of increasingly realistic global climate models and upon theavailability of global observations needed to verify and improve the models.

REFERENCES

1. Hansen J., I. Fung, A. Lacis, D. Rind, G. Russell, S. Labedeff, R. Ruedy andP. Stone, 1988, Global climate changes as forecast by the GISS 3-D model,J. Geophvs. Res. (in press).

2. Hansen, J., A. Lacis, D. Rind, G. Russell, P. Stone, I. Fung, R. Ruedy andJ. Lerner, 1984, Climate sensitivity: analysis of feedback mechanisms,Ggonhvs. Mono., U, 130-163.

3. Manabe, S., R. T. Wetherald and R. J. Stauffer, 1981, Suimer dryness due toan increase in atmospheric CO2 concentration, Clifate hna, ', 347-386.

4. Hanabe, S. and R., T. Wetherald, 1986, Reduction in summer soil wetness In-duced by an increase In atmospheric carbon dioxide, Science, =3, 626-628.

5. Hanabe, S. and R. T, Wetherald, 1987, Large-scale changes of soil wetnessinduced by an increase in atmospheric carbon dioxide, J. Atmos. Sci., j4,1211-1235.

6. Hansen, J. and S. Lebedeff, 1987, Global trends of measured surface airtemperature, J. G0oohs. Res., 22, 13,345-13,372; Hansen, J. and S.LAbedeff, 1988, Global surface air temperatures: update through 1987,Geohvs. Ras. LAt., U, 323-326.

7. Grotch, S., 1988, Regional intercomparisons of general circulation modelpredictions and historical climate data, Dept. of Energy Report,DOE/NBA-0084.

47

4

GLOBAL TEMPERATURE TREND

lo1940DATE

74. 1. Global surface air temperature canm for the past century, vith thesoro point defined a" the 1951-1980 moan. Uncertainty bars (950 confidencelimits) are based on an error analysis as described in reference 6; irer barsrefer to the 5-year moan end outer bars to the wal moan. The analyed un-certainty Is a result of Incomplete spatial coverage by masurement stations,primarily in ocean areas. The 1988 point compares the Jaiwary-Hay 1988 tempera.ture to the man for the sae 5 montba in 1951-1980.

9 . .-l~ l . ..

6I -.... l lff " l iure 1"ionP.4

it I

1958 1965 1970 9975Dote

1990 1965 1936

fig. 2. Global surface air temperature change at seasonal resolution for thepast 30 years. figures 1 and 2 are updates of results in reference 6.

0

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48

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-v v v v v Vv

1960 1970 1980 1990 2000 2010 201C,Date

Fi. 3. Annual man global surface air temperature computed for trace gse scenariosA, A and C described in reference 1. (Scenario A asums continued grvth rates oftrace ga emissions typical of the past 20 years. I.e., about l.5% ywr" emissiongrovwt; scenario I has emission rates approximately fixed at current rates; scenarioC-drastically reduces trace 4s emissions between 1990 and 2000.1 Observedtemperatures are from reference 6. The shaded range Is an estimate of globaltemperature during the peak of the current and previous interglacial periods, about6,000 and 120,000 years before present, respectively. The zero point forobservations is the 1951-1950 man (reference l; the sero point for the model isthe control run mean. .

SCENARIO 8AEAn AT.*O.tC JULY 194 MEAN AT ,*O

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irg. 4. SImulated July Saf&" air tWWrawr. amamils 9C 6t i"dV~I*&m .VeO Of OcOnzIo 2,cmoqsred to a 100 yar control run with 1956 atmopberl c oeom (an Attachumt A).

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A%.ACHHENT A

Global Cliiiate Changes as Forecast by the GISS 3-D ModelJ. HANSE L UNO, A. LAc D. Rzt. S. LmEDW. R. RU DY. 0. RSS

1MM GdW *m fak Cw huslw or* eft Now Yw*

P. SToNE

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We M4 . o dimae mode, ovr Model N wk V by I0" horaocald mtsolukim toalumma se de dimes oase of she dapesadea weo of esmoealc u siam u d aets.Horao bw uhmanm by oase u & maed s dimes. sad uptake ofbas -pWom by Ose os bmassthe mad h aimd im Vuic dtagow WeNo ma 3pew * u , ad pas INS .heaeo1 w sm meeum Um ao at uo 1 ioss

I N esd m 19M m d emd or emked Ab i ssmoephe* lC CH .NO, seoh OMwk Iked pa io trM U so the preScmmio A sume

ubievr um 9 SWAM & dMONmd , OW NN oQW* Of MW soumselo C emma IW mm of U ps pwhelm As 0he ao s diN am-to *OFes 3i woa P1ap am trm atem0slms we a ) ad imind so the Uevessaieed A the peek of the aime die~ei pe woo ocugean s Mi adkmawaelys coee esde an 4mm =hic ianes is Wee U of Eiwa - e.depdho asp. Pawt1 (2) lbW geeowe hnat *mu to doe chdy ide oble he the *W ooermiag

b Mshe ahem s Lae3eapmas h-df so tuck sad xmeduls a Wval a m he esteeddevido hve the dAS~~Ih - INWeoff 10 (3) Roghom whes m uembiguau sumea appeas

aamwe bw lesud amps Chime ead -eeul*rmarm Is Ais* ad oms sim ar Amsaesia &Wd

so iat t 6k dodhe pmof s blhessM iaaahowby --hIs~ cheep. in shfipm o -ma d by P11 I Mom wit pevous di.buade lb.FTk mwod" eut

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foaag sh eumpoe ia~dq essupakesa sueaoe by! she . wesad she osluho. of otherleesu dmul baeiW

to appear In J. Geophys. Res.

Studes of te dium -ve if 11InmSi umwouwC2have been made by mesm of useams with sines.

dbmeiomi (3.D) lbem. madek %*khih she mov of=wu bmmom &~d o 9sa6uVin with the

(Mmii sad We~wfI, 5 mmb wAN SAoutfr, 196Bom wad., 1ION, Wkris, md feii, 19U4; H9um wadMauiw, 1373 1bw mdiik d d a Wug dke

b~m at*q~bd fr dmbed 06with 0"bIm ofdftwkb 0 K dMS

Howee, ub1,eewmlm chow that I,:: Is nrsnpeduaWy t ubu~am u 31S pm (puts par mlb byvalis) to 1M5 when Xeli inkime scrme messrs.so sod b am @bout W4 ppm wth Pe -me smalinasma of chst 1.5 ppm Iteulag a f, 1323. Me*do*s we At baut wo othe boe glob a sie ferimpof comperbl mgnWde:. Foath of semiw other ampm [W&* s a f., IVK La*b a f., M96; Rawuwuw. aat., 1965 and vaidom In mtroabl& c *ma ti ovaboic arpdma (Lamb, IM, idbsn, 19M SAMWedAfar, 1975 AW" of atif, m am" Ri st atd,1, - 19M60Rehash, 1MI. &M other rmiscleO fo uch a&" ofeolur ines , Wropswle Wmch sd lad

pr~ opertie my Nho be alpfidcm, bet qmmadveino buo bimaffidew to dubsm she a" of shie

fordap ame the Put NN"rs deweIs shi pipr we Wud the mveapbse Of a 3-D g0be

dhme model to mesd mae of chmp of raiatvefornft mahanlm The uule reepowe of she doumsqyste an demdu timewake depsuaw i aly oanshefsawe of she oceam for w"ic adepm vsdorumdabsod dynamcs modeb we SOt avaiab. Owr procedure bn sovample asasapti ot c omet hemmqwsorqedfi-sa* we amn tho ding the am few desads the nmad pieser of hoehontal oom ham -,pa -1e wU nooaiiw age sad dhe roos of bes uptake by she oembawnt he mabed layer be Opprulnaed by divoawn of hem parstimo M&i arprheb~e rqpsesataoso Of do cam proved a am mituue of she glbatramim Owem reqesm *w cm be umpared to boshobsrvome and fahm dsabdm dwdeoped with a*inmlic*l husi e ocam We inaftd b s pqwe aduF 4 d, of Owu enerimems and en maki of computsedumpumare cams; ohe ompad qamitise mc a-w in dhe Iumo-hId peem shrulsak, IavCahsdcendu m mm w bepreiatsdh6whers

The dkn mode imf la i in ew **u is &=Wfube inSestilm Rseo alO yeacm iurol r"afs*AsmodAlwo the UmOqabmt campodtfol ft We bq*fl &esosIedbn Section 3. Thre soemise for amoqahir umc pmnsad uruoqbel am" we definedl is Sean 4. iseeuiof the dblat xme iWmoos for shie three wMaloswe ;re-uwd i Seabom 5; Sectisn 5.1 aamnse shepv&Qced -o warming and she iust of when she g0bewarming shoul amied nature clime varimbihay, Section5.2 mxamin the "Wla dusrbutio of pedad desade

UepaOhn-dtmp and Sis 3 nsm ht-ewmwd local um ,wu dmp . Is she &el asson. weuwubo the modi predieb ad dom she Wp,6sula Bso and ,a,=don Wom w,, sh pts dsp,,

Owt t-m i I s c m smm a mis in itived insey19M3 bedn rem a bachpound job as thu 0135 mainfrm000ue, A pars people mCMe (AambW V-6) *(md19'e Vk mmp. Rt for coenio A wm reported im aosigerenos in haS 16 (urOMed pvblsAd by Shad,

2. Qm~lu lions.

The asoqabrl o"oauu or the 0"be dwe modwe enmloy is delrted md b abilities ed Lsts m fordmulivg todays chast we dscaumew~ s oeplado atf., 19A heiter refere to'd pie 1). Themode s she a roes eudoas for meuvatlos of

fmtowe, mme ad wower d w sad the -mni

ofm. we a m eers p-I ihm enqdl ia and

mF~ ~ ~ ~~p 'd vqmmuul P kudnm md

hmso l msob r blitaf by 10 WOWlegtu d The

$mAW&Mu puss, maro ad po owd patiles. o coersadbhlgsswecscss-j bas cdsdIy in aMiedssfassom of coud tpeM d ad itae Th deam.

,nd s lm ;. sdis we i,1; de d by*og, andmince abide d&"W syo the Wcei vapcmis Snw*Ph is coputed sad em- m abide inclde lem o( atosr sad mukin by uma. The eqalbshsm sensiiviyof th Model for d med CO (31S ppm -M ppm) is 421Cfor gl oba mie ufac * suamc PN& or a/ im.16,e-nMai erd so as per 43 Ts Is wikn but marsh vpw ad at the rugs * LM etmated for clmaeaadIey by Natic) MAdma ofr ee om e deje3pe., im, Smaak*s M4,o9 whto the rae in atbjs'dmIas emlus of di uaeay based an dkmuemoduft Oitu sad ANO 64 evds fu chums sa-iisy. The mUNdvity au m od b am he mkdi ofthe w obedied ( omo to"w"h Oc4a WerA"Vwad Afeal, 196;Pyw 2, 1144; Mom~ w Namd, 137;

am Adilaw, 134

Ogleel bn She weno of model 11 dowmmed in poer 1.Is the upeIhema dswited her sad in piper %, omen

.I ; -usr- ad Ice save we oumpased basd on eog-tW O w 11h sh 1in1'e sCOM hem tpres , and

She seem's hem mpscy. ThU teummats of omen-I -qmr s-ad its ser we aedu them bus as inpqe2wholwer a % rt"m in apqrer2inom theObjectve I s"o ftud squmm*m (5 .) chums champs,aftlaater time w"s aavc by ipeclyig the medum m"Welayer d" & athr A f as &&wm dib besm ecap htbstN sh died lye sad she deepe omma. In tMwe, &inc we we cocused wit the P -- 9s limatIrp ime, we incude she entie mined laye wft scuasallwatg depthqucfd fro obeervuloas m deecrisd InAppansh A ad (mmp in the ontrol ru) we allo*

2

!.-.'_

o

52

diffusive vertical hem transport beneath the level definedby the annual-maximum mixed layer depth. The global meandepth of this level is about 125 m and the effective globaldiffusion coefficient beneath it is about I cmst.

The horizonal transport of heat in the ocean is specfiedfrom estimates for today's ocean, varying seasonally at eachridpoint, aa described in Appendix A. In our experiments

with changin atmospheric composition we keep the oceanhorizontal heat transport (and the mixed layer depth)identical to that in the control run, i.e., no feedback ofclimate change on ocean hea transport is permitted in theseexperiments. Our rationale for this approach as a first stepIs that It pemits a realistic atmospheric simulation andsimplifies analysis of the experiments Initial experimentswith an Idealized interactive atmosphere/ocean model suggestthat the assumption of no feedback may be a good firsapproximation for onaU cimate perturbations in thedirection of a warm climate PDym et at., 1964; Manabeand Dom, 19&5. In addition, experimetts with a zonalaverage heat balance model aunest that the global averageclimate sensitivity does not depend strongly on the feed.bad in the ocean heat transport [Want o a., 19641.However, we stress that this "rrise-ree representationof the ocean excludes the effects of natural variability ofocean transpors and the possibility of switches in the basicmode of ocean circulation. Bn,,cker et al. 119851, forexample, have suggested that sudden changes in the rateof deep water formation may be associated with osdil-lations of the climate t'stem. Discussions of the transientocean response have been given by Schneider and Thompson119811, Bryan et al. 11984), and others. We consider oursimple treatment of the ocean to be only a fost step instudying the climate response to a slowly changing climateforcing, one which must be compared with results fromdynamically interactive ocean models when such models atreapplied to this problem.

3. 100 YEApt ComrmoL RuA 100 yea control run of the model was carried out with

the atmospheric composition fixed at estimated 1958 values.Specifically, atmospheric gases which are time dependent inlater exeiments are set at the values 31S ppm for CO.,1400 ppb for CH4, 292.6 ppb for N20, 1S.S ppt forCL I,? (P11), and 50.3 ppt for CC0F3 (F12).

The ocean mixed loa depth varies geographically andseasonally based on limatological data specified in AppendixA. No beat exchange cos the level defined by the annualmmimumimzed layer depth was permitted in the contr rundescribed in this section. The purpose of this constraintwas to keep the response time of the model short enoughthat it was practical to extend the model integration overseveral time constants, thus assuring nea equibrium con-ditions. The isolated mixed layer response time is 10-20yeats for a climate sensitivity of 40C for doubled CO. asshown in paper 2. Note that the seasonal thermocine (i.e.,the water between the base of the seasonal mixed layer andthe annual-it naimum mixed loa depth) can have a different

temperature each year, this heat storage and release canaffect the interannual variability of surface temperature.

The variation of the global-mean annual-mean surface airtemperature during the 100 year control run is shown inFigure 1. The global mean temperature at the end of therun is very similar to that at the beginning, but there issubstantial unforced variability on all time scales that canbe examined, that is, up to decadal -time scales. Note thatan unforced change in global temperature of about 0.4C(031C if the curve is smoothed with a 5 year running mean)occurred in one 20 year period (years 50-70). The standarddeviation about the 100 year mean is 0.11C. This unforcedvariability of loal temperature in the model is onlyslhtly smaller than the observed variability of globalsurface air temperature in the past century, as discussed inSection 5. The conclusion that unforced (and unpAdictable)climate variability may account for a large portion of pasclimate change has been stressed by many researchers; forexample, Lorenz J196), Hasselman 11976) and Robock 11978).

The spatial distribution of the interannual variability oftemperature in the model is compared with observationaldata in Plate 1. The geographical distribution of surface airtemperature variability is shown in Plate la for the modeland Plate lb for observations. The standard deviationranges from about 02MC at low latitudes to more than I'Cat high latitudes, in both the model and observations. Themodel's variability tends to be larger than observed overcontinents; this arises mainly from unrealisticaly largemodel variability (by about a factor of two) over thecontinents in summer, as shown by the seasonal graphs ofHansm and Lbedeff 11987). The interannual vs-iobilhty ofth.: zonal mean surface air temperature, as a function oflatitude and month, is shown In Plate Ic and Id for themodel and observations. The seasonal distribution ofvariability in the model is generally realistic; except thatthe summer minimum in the Northern Hemisphere occursabout one month early. The interanual variability oftemperature as a function of height is more difficult tocheck, because observations of sufficient accuracy arelimited to radiosonde data. J. Angell (private communica-tion) has analyzed data from 63 radiosonde stations,averaged the temperature change zonally, and tabulated thedata with a resolution of save- latitude bands and fourheights, the lowest of these heights being the surface air;the inserannual variability of the results is shown in PlateIf. Reasons for smaller variability in the model, Plate 1t,probably include: (1) Identical ocean heat transport everyyear, which nbits occurrence of phenomena such as ElNifio and the associated variabWty of upper air temperature,and (2) stratoopherIc drag in the upper model layer of the9-lar model 1I, which reduces variability in the strato-sphere and upper troposphere as shown by experiments witha 23-lay r version of the model which has its top at 85 kmRINd ei di., 1988).

We use these interannual variabilities in Section 5 to helpestimate the signifilcance of predicted climate trends and tostudy where it should be most profitable to search for early

3

evidence of greenhouse climate effects. We defer furtherdiscussion of model variability and observed variability tothat section.

4. PADLAivE FORCING iN ScErAPuos A, B A.,,D C

4.1. Trace gases

We define three trace gas scenarios to provide anindication of how the predicted climate trend depends upontrace gas growth rates. Scenario A assumes that growthrates of trace gas emissions typical of the 1970s and 1980.will continue indefinitely; the assumed annual growthaverages about 1.5% of current emissions, so the netgreenhouse forcing increases exponentially. Scenario B hasdecreasing trace gas growth rates such that the annualincrease of the greenhouse climate forcing remains approxi-ma!ely constant at the present level. Scenario C drasticallyreduces trace gas growth between 1990 and 2000 such thatthe greenhouse climate forcing ceases to increase after 2000.The range of dimate forcing covered by the threescenarios is further increased by the fact that scenario Aincludes the effect of seven hypothetical or crudelyestimated trace gas trends (ozone, stratospheric water vapor,and minor chlorine and fluorine compounds) which are notincluded in scenarios B and C.

These scenarios are designed to yield sensitivity exeri-ments for a broad range of future greenhouse forcing.Scenario A, since it it exponental, must eventually be onthe high side of reality in view of finite resource con-uraints and environmental concerns, even though thegrowth of emissions in Scenario A (a 1.5 yr'i less thanthe rate typical of the past century (" 4% yr"). ScenarioC is a more drastic curtailment of emisions-than hasgenerally been imagined; it represents elimination ofchlorofluorocarbon emissions by 2000 and reduction of CO2and other trace gas emissions to a level such that theannual growth rates are zero (i.e., the sources just balancethe sinks) by the year 2000. Scenario B is perhaps themost plausible of the three cases.

The abundances of the trace pa In these threeaeos are specified in detail in Appendix B. The ne

greenhouse forcing, AT., for these scenarios Is llutted inFigure 2; ATo is the 'computed temperature change at equii-brium (t - ) for the given change In trace gas abundances,with no climate feedbadcs included (pff 2]. Scenario Areaches a climate forcing equivalent to doubled CO, Inabout 2030, scenario B reaches that level in about 2060, andscenao C never approaches that level. Note that ourscenario A goes approxmately through the middle of therange of likely climate forcig estimated for 2030 byRomanathwt etl. 119 , and scenario B ix near the lowerlimit of their estimated range. Note also that the forcigin scenario A exceeds that for scenarios B and C for theperiod from 1958 to the present, even though the forcing inthat period is nominal based on observations; this isbecause scenario A includes a forcing, for some speculativetace gas changes in addition to the measured ones (cf.

53

Appendix B).Our climate model computes explicitly the radiative

forcing due to each of the above trace gases, using thecorrelated k-distnbution method (poper 1). However. weanticipate that the climate response to a given globalradiative forcing AT, is similar to rr order for differentgases, as supported by calculations for different climateforcing in paper 2. Therefore, results obtained for ourthree scenarios provide an indication of the expectedclimate response for a very broad range of assumptionsabout trace gas trends. The forcing for any other scenarioof atmospheric trace gases can be compared to these threecases by computing AT0(t) with formulas provided inAppendix B.

4.2. Stratospheric oemsolsStratospheric aerosols provide a second variable climate

forcing in our eperiments. This forcing is identical in allthree experiments for the period 1958-1985, during whichtime there were two substantial volcanic eruptions, Agung in1963 and El Chkh6n in 19111 In scenarios B and C,additional large volcanoes are inserted in 1995 (identical inproperties to El Chich6n), in 2015 (identical to Agung), andin 2025 (identical to El Chch6n), while in scenario A noadditional volcanic aerosols are included after those from ElChich6n have decayed to the background stratosphericaerosol level. The stratospheric aerosols in scenario A arethus an extreme case, amounting to an assumption that thenext few decades will be similar to the few decades before1963, which were free of. any volcanic eruptions creatinglarge stratospheric optical depths. Scenarios B and C ineffect use the assumption that the mean' stratosphericaerosol optical depth during the next few decades willbe comparable to that in the volcanically active period1958-1963.

The radiative forcing due to stratospheric aerosolsdepends upon their physical properties and global distri-bution. Sufn:ient observational data on stratosphericopacities and aerosol properties is available to define thestratospheric aerosol forcing reasonbly well during the pastfew decades as described in Appendix B. We subjectivelyestimate the uncertainty in the global mean forcing due tostraospheric aerosols as about 25% for the period from 1958to the present. It should be possible eventually to improvethe estimated aersol forcing for the 19S0s, as discussed inAppendix B.

The global radiative forcing due to aerosols and green-house gua is shown in the lower panel of Figure 2.Stratospheric aerosols have a substantial effect on the netforcing for a few years after major eruptions, but within afew decades the cumulative C02/trace gas warming inscenarios A and B is much greater than the aerosol cooling.

S. TkANamr SwuL'notu5.1. Global Mean SsrfaceAir Temperor

The global mean surface air temperature computed for

54

scenarios A, B and C is shown in Figure 3 and comparedwith obsmvions, the latter based on analyse of Hansenend Lebed r 119671 updated to include 1966 and 17 data.Figure 3a is the annual mean result and Figure 3b is thefive year running mean. In Figure 3o the temperature range0.50-1.09C above 1931-1960 climatology is noted as anestimate of peak global temperatures in the current andprevious interglacIal periods, based on several climateindicators [NAS, 1973); despite uncertainties in recon-snacting global temperatures at those times, it is signif-atm that recent Interglcial periods were not much warmerthan today.

Interpretation of Figure 3 requires quantification of themagnitude of natural variability, In both the model andobservations, and the uncertainty in the measurements. Asmentioned in the description of Figure 1, the standarddeviation of the model's global mean temperature is 0.111Cfor the 100 year control run, which does not include thethermodine. The model simulations for scemrios A, B andC include the thermocline beat capacity which slightlyreduces the model's short-term variabt howev,'udingfrom the results for scenario A, which has a smoothvariation of climate forcing the models standard deviationeremansit about 0,lC. The standard devition about the 100

year mean for the observed surface air temperature dngeof the pet century (which has a strong trend) is 020C;it is 0.12C after detrending (Hensen n ., 19611. The0.12'C detreuaded variability of observed temperatures wasobtained s the average standard deviation about the ten10-yea means in the pest century I instead, we computethe average standard deviation about the four 25-yermeans, this detrened variability is 0.130C. For the period1951-190D, which is commonly used as a reference period,the standard deviation of annual temperature about the 30.year mean Is 0.131C. I Is not surprising that the vari-ability of the observed global temperature exceeds thevaribility in the G{0 control nun since the latter containsno variable cliuste fordngs such as changes of atmosphericcomposition or solar ktrdiance; also specficatio of oceanbeat transport reduces inseranual variability due to suchphenomena as El NIho/Southemn Oscillation events. Finaly,we note that the ono-im error in the observations due toIncom plete erage of station is about 0.0O C for the

period from 1956 to the present Hi mm .sd eedff,6J, which does no w contribute appreciably to the van.-

ability (standard deviation) of the observed global tosaera-tar. We conclude that, on a time scale of a few decadesor less, a warmng of about 0.4O is re red to be as-ficant at the 3# level (9S confidence level).

There is no obvioudy significant winning trend in eitherthe model or observations for the period 198.-1963. Duringthe single year 1901 the observed temperature nearlyreached the 0.4C level of warming. but in 1964 and 1985the observed temperature was no prester than in 1938.Early reports show thai the observed temperature in 1967agin approached the 0.4"C level Hansen wad Lebedeff.1988], principle as a result of hig tropical temperatures

associated with on El Nifo event which was present for thefull year. Analyses of the influence of previous El NiAos onNorthern Hemisphere upper air temperature jPriroo andOca, 19641 suglest that global temperature may decrease inthe nat year or two.

The model predicts however, that within the next severalyears the lObal temperature wi reach and maintain a 3olevel of global warming, which is obviously significant.Al this conclusion depends upon certain assumptions,such as the climate sensitivity of the model and the absenceof large volcanic eruptions in the net few years, adiscussed below in Section 6, it Is robust for a very broadrang of assumptions about CO, wn trace gas trends, asIllustrated in Figure 3.

Another conclusion Is that global warming to the levelattained at the peak of the current interglacial and theprevious interglcial appears to be inevitable; even with thedrastic, and probably unrmalstic, reductions of geenhouse

,forcn in scmario C, a warming of 0.MC is attainedwithin the neat 15 yews. The eventual warming in thisscenario would uceed I'C, %esed on the forcing illustratedin Figure 2 and the feedachftror f w 3.4 for our CM[papc 2). The 1C level of warming Is eceeded during thenext few decades in both wenarios A and B; in scenario Athat level of warming is reached in less than 20 years endin scenao B It is reached within the m 25 years.

32. Spaial DisuOsiwon ofJDcadal Temperour Changes52.1. Geogrlpic.a dimribution. The geographical distri-

bution of the predicted surface air temperature change forthe intermediate scenario B Is illustraed in the left columnof Plate 2 for the 1960s. 1990 and 2010s. The right columnis the ratio of this decadal temperature change to the inter.annual variability (standard deviation) of the local temperm-sure in the 100 year control run (Plate 14). Sirte theinteranmnsl variabilky of mrfae a temperature in themodel. is reasonably similar to the variability in the realworld (?Wae lb), this ratio provides a practical measure ofwhen the predicted mean geenhouse wrming is locallysithfcent.

Averaged over the ful decade of the 1980 the modelshows a tendency toward warming bet in mou regions thedecdal-me wiring is les than the inerannus vari-Ability of the annual mes. In the 1990a the decaal-meanwarming is conperable to the interannual variability formay roons, nd by th 2010 almost te wtre globe hasvery substantial warming. as mud as several times theinterannwal variabili of thM m I mean.

The warming is generally pter over land than over theocean, and rter at hNoh latitudes than at low latitudes,being especal large in rgons of ma ke. Regions wherethe warming shomw up mot prominently in our model.relative to the interannual variability, ae: (1) low latitudeocean reons where the surface repome time is small(Figure 13 of paper 2) due to a shallow ocean mixed layerand small thermocline diffusion, specifially reons such asthe Caribbean, East Indi, Bay of Bengal, and large pans

55

of the -Indian, Atlantic and Pacific Oceans near or justnorth of the equator, (2) China, where the model's varia-bility is twice as large as the observed variability, (cf. Plate1) and the interior downwind portion of the Eurasiancontinent, eapecially the Kazakh-Tibet-Mongolia-Manchurisregion, and (3) ocean areas near Antarctica and the NorthPole, where sea ice provides a positive climate feedback.The regions predicted to have earliest detectability ofgreenhouse waming are undoubtedly model dependent tosome anent; as discussed below, this model dependence, inconjunction with global observations, may soon providevaluable information on dlnite mechanlam

The predicted signal/noie ratio (aT/o) is generally smallerat any gm geographical location than t is for the globalmean (Figure 3), because the noise is dgnf antly reducedin the global average. Thus for the single purpose ofdetecting a greenhouse warming trend the global meanteml. ature provides the best sital. The geographicaldistribution of the predicted global temperature change alsocan be used for "opimal weighting" of global data toenhance early detection of a climate trend IMe/, 1962J, but,the impact of such weighting is modest and model depen-dent.

Our results sugest that the geographical patterns ofmodel predicted temperature chage in combination withobservations, should become valuable soon for discriminatingamong alternative model results, thus providing informationon key climate processes Ohich in turn may help narrow therange for predictions of future climate. For example. Plate2 shows a strong warming trend in sea ice regions borderingthe Antarctic continent; on the contrary, the ocean atmos-phere model of Mwawbe and Brn (private communication)shows cooling in this region for the first few decades afteran instant doubling of atmospheric CO2 . The contraryresults probably arise from different heat tanspors by theoceans in the GISS and GFDL models. As a second =wnple,our model yields a strong warming trend at low latitudes asdoes the BMO model [Wdrcn and Miehu, 197J, while theGFDL and NCAR models fWashi and MeWl, 1984J yieldminimal warming at low latitudes. The contrary results inthis cae may aise from the retments of mot Convection,as the 0ISS and BMO models ue patradie convectionschemes and the GFDL and NCAR model use a moistadiabatic a4ustment. Judging from Plate Z the real worldlaboratory may provide empirical evidence releat to suchclimate mechanisms by the l99s.

522. L.ar'int-son disnNuiom. Th dependese ofthe predicted temperature changes on sesm Is invetedin Plate 3. which shows the predicted surface air tempera-ture change for scenado B as a function of latitude andmonth (left side) and the ratio of this to the model's inter-annual variability (right side). Although the largest Are areat high latitudes and in the winter, the variability is alsolargest at high latitudes and in the winter. Consikeng alsothe differences between the model's variability and observedvariability (Plate I), Plate 3 suggests that the best place tolook for greenhouse warming in the surface air may be

middle and low latitudes in both hemispheres, withsignal/noise in summer being as grcat or greater than inwinter.

5.23. Laoiaude-heiht diswibaon. The dependence ofthe predicted temperature changes on altitude is investigatedin Plate 4, which shows the predicted upper air temperaturechange a fntion of pressure and latitude (left side) andthe ratio of this to the model's nterannual variability (rightside). Although the predted greenhouse warming in ourclimate model is greater in the upper troposphere at lowlatitudes than it is at the surface, the signal/noise ratiodoes not have a strong height dependence in the tropo.sphere. The dominant characteristic of the predictedatmospheric temperature change is stratospheric cooling with'troposphei warming. This characteristic could be a usefuldiagnostic for the greenhouse effect, since, for example, atropoapherk warming due to increased solar irradianceshould be accompanied .,y only a sight stratospheric cooling(d. Figure 4 in paper 2). However, the large signal/noisefor the stratospheric cooling in Plate 4 is partly an artifactof the unrealistically snal variability at stratospheric levelsin our 9-layer model; the model predictions there need to bestudied further with a model which has more appropriatevetical structure.

.2.4. Cb $paiuos ith obsorions. Global maps ofobserved surface air temperature for the first seven yearsof the 1960's show measurable warming, compared to obscr.vatilns for 1951-1980, especially in central Asia, northernNorth America. the tropics, and near some sea ice regionsIHaman et a., 1967. There are general similarities betweenthese obwrvd patterns of warming and the model results(Plate 2); the magnitude of the warming is typically in therange 0-5-1.0o defined in Plate I. Perhaps a more quanti-tative statent could be ma& by using the observationaland model da in detection schemes which optimally weightdifferent georahical regions leg., Bell, 1982; Bwumett,1966J. The significance of such comparisons should increaseafter data are available for the last few years of the 1960swhich are palicularly warm in the model. However,informaton from the pattern of surface warming is limitedby the fact that similar patterns am result from differentdimate forcings PMdoabe and We wdd, 1975; p per 2.

Comparison of temperature changes a a function ofheight may be more diagostic of the greenhouse effect, asmentioned above. Analysis of rdiosonde data for the peod1960-1985 by Anaefi 11906) suggests a global warming ofabout 030C in the 300-50 mb region and a cooling of about0.5C in the 100-300 mb and 50-100 mb regions over that 25year period Although the warming in the lower tropo-sphere and cooling in the sratosphere are consistentwith our model results (Plate 4), the upper tropospheric(100-300 mrb) cooling is not. The temperature changes areabout 03-1., based on the natural variability in the modeland observations (Plate 1). Note that our illustrated modelresults are for the pe.1od 196I0-99.

None of the climate models which have been applied tothe greenhouse climate problem yield upper tropospheric

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cooling as found bi observations by APrf (1966J. If thischaraeriIc of the observations persists over the nestseveral year. as the modeled temperature changes reachhigher levels of mathematical flgnlficance, it wi suggesteither a common problem in the models or that we need toinclude additional dimate forcing mechanism in theaalyse Although the rnd in th observations is not yetdear, it is perhaps worthwhile to point out examples ofmechanisus which coud produce a &s ny betweenmodel and observations.

Corning posb common model problems a primea prior candidate would be the modeling of moist convey.rit, sim it k a prinial proem determining the verticaltemperature raim. However, the treatment of Convectionin the models (GFDL, GISS, NCAR and IMO) ranges frommoist adabatic adustmemt to pontratng covecteon, and alof them models obtain strong upper tropoqpheri warming.A more Iely candidate among imenal model defdienmay be the clud feeb . Althh some of the modelinclude dynamlca/rsdiastit cloud fe d ., they do notinclude optcal/radative fedbeaci For u ple, it isposesle that the oacity a( (upper tropmqbel) cirscouds may increase in a warming climate; this wouldincrease the greenhouse effect at the surface while causinga coof in the upper tropoqpaere.

A good candidate for changing the temperature profleamong clmae forcing is change of the vertical profile ofmoon, ne some observations suggest deaeasing ozoneamounts in the upper tropospher and stratosphere alowith I eu in the lower troposphere (Bolk e o.. a,161.Another candidate climae forcing is change of the atmos-pheric aerosol distribution; a discussed In Appon& B, itwill be possible to specify changes of stratospheric aeroslsin the 19Ws more acsrately than we have attempted In thispaper, but HUe information is availe on changes intopoqphrec aerosols. SO another cmdidate climateforcing k solar varlbl, although changes of total solar

adiana such as reported by Wlswt at o. 11966J wouldno yield opposite responses in the upper and Iowatropoqer d s in the spectral distribution of the sorcradisnce may have a moe mplimted effect on tempera-

These examples pou ot the need for several obermva-tion of climate fongt mecimtms and climate ffeetakprocesses during m in years as th greenhouse effecainaeeass Suds observations, are essential If we ae torelal interpret the cusm of climate d g ad theimplications for Nnhser cA

53. S -wvwm and Laoc Tmperwaw Ch aesAlthough lo germ g-at arges ase the

stal/noin ratio of greenhouse effects, it Is Important toAlso mmine the model predictions for evidence of green-bouse effects on the frequency and global distribution ofshort-term climme disturbance Such studies will bemded to help uner practical questions, such as whetherthe greenhouse effect has a role in observed local and

regional climate fluctuations.We illustrate here samples of model results at seasonal

and monthly temporal resolutions, and we estimate theeffect of the temperature changes on the frequency ofwmreme temperatures at specific locales The object is notto make predictions for specific years and locations, butrather to provide some iMntion of the magnitude ofpractical impacts of the predicted temperature changes.

53.1. Ssmter mid oeter mqas We compare in Plate 5the computed temperature changes in scenados A, B and Cfor June-July-August and December-January-February ofthe 1990s. In both saons the war is much greater inscenario A than in scenarios B a C, as also , lustratedin Figure 3. The relative warminp are consistent with theglobal radiative forcing for the three scenarios shown inFigure 2; the greaer forcing in scenario A arises partlyfrom greater uce pa abundance and partly from theassumed absence of large volcanic ruptioms.

Features in the predicted warming common to aU scenarosinclude a tendency for the greatest warming to be in seaIce regions and land arems, as opposed to the open oceans.At high latitudes the warming is greater in winter than insummer. We also notice a tendeimcy for certain patterns inthe warmn, for mample, greater than avem warming inthe eastern United States and les warning in the westernUnited States. Examination of the changes in sea levelpressure and atmospheric winds suggests that this pattern inthe model may be related to the ocean's response time; therelatively slow worming of surface waters in the midAtlantic off the Fastem United States and in the Pacific offCalifomis tends to increase sea level pressure in thoseocean regions and this in turn tends to cause moresoutherly winds in the eastern United States and morenortherly winds in the western United States. However, thetendency is too smal to be apparent evesy year; in someyears in the 19901 the eastern United States Is cooler thndimatokly (the control run mea) and,often the westernUnited States is substantially warmer then cimatololy.Moreover, these regional patterns in the warning could bemodified If there wer major ranges in ocean heat

3. . Ady mq . We mamm in Plate 6 the temperaturechanges in a single month (July) for several different yearsof scenario B. In the 1905s the glob warming is smallcompared to the natural variability of local monthly meantemperature; thus any given location is about as ltely to becooe than climatoWt& as warmer than climatology, and, ushown in Plate 6, the a with cool temperatures in agv July is about as great as the arm with warm tempera-tures. But by the year 2 the is an obvious tendencyfor it to be warm in more regions, and by 029 it is warmalmost everywhere.

Mo"r temperature anomalies can be readily noticed bythe average person or "malt-in-the-reet'. A calibrationof the magnitude of the model predicted warming can beobtained by comparison of Plate 6 with maps of observationsfor recent years, s published by Hansen el a/. 119871 using

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the same color scale as employed here. This comparisonshows that the warm events predicted to occur by the 2010sand 2020s are much more severe than those of recentexperience, such as the July 1966 heat wave in theSoutheast United States, judging from the area and mag-nitude of the hot regions.

513. Frequency of e urme events. Although thegreenhouse effect is usually measured by the change ofmean temperature, the frequency and severity of extremetemperature events La probably of greater importance to thebiosphere. Both plants and animals are affeaed by extremetemperatures, and regions of habitability are thus oftendefined by the range of local temperatures.

We estimate the effect of greenhouse warming on thefrequency of extreme temperatures by adding the modelpredicted warming for a given decade to observed local dailytemperatures for the period 1950-1979. This procedure isintended to minimize the effect of errors in the control runclimatology, which are typically several degrees Centigrade.The principal assumption in this procedure is that the shapeof the temperature distribution about the mean will notchange much as the greenhouse warming shifts the mean tohigher values. We tested this assumption, as shown inFigure 4 for the 10 gridboxes which apprimastely cover theUnited States, and found it to be good. The Iustrated caseis the most extreme in our scenarios, the decade 2050s ofscenario A, for which the global mean warming is about4C. Note in particular that there Is no evidence that thedistribution toward high temperatures in the summerbecomes compressed toward the mean as the mean increases;indeed the small change in the distribution which occurs isin the sense of greater variability, suggesting that ourassumption of no change in the distribution wilil yield aconservative estimate for the increase in the frequency ofhot events.

We also examined the effect of the greenhouse warmingon the amplitude of the diurnal cyde of surface airtemperature. In our doubled CO experiment paper 21 thediurnal cycle over land ares decreased by 07'C, withgreatest changes at low laitudes; for gridboes in theUnited States the changes of durnal amplitude ranged froma decrease of OA'C to an increase of OSC. The cungesof diurnal amplitude in the mnsient xperimens variedfrom gridbcs to gridbox, but did not exceed several tenthsof a degree centigrade. Th's for simplicity we negledthis effea in our esmaes of changes in the feuencies ofememe temperatures.

Tbe estimated cag in the mean number of days peryear with temperature coding 95? (3C), minimumtemperature exceeding 75?F (a 24C), and minimum tempera-lure below 32rF (C) is shown in Figure 5 for severalcities. The senario results were obtained by adding themean decadal warming (relative to the last nine years of thecontrol run) of the four model grildpoints nearest each cityto the 1950-1979 observed temperatures. We employ abroad-area 10-year mean change, so that the variability isprovided principally by the observed dimatology.

The results in Figure 5 illustrate that the predictedchanges in the frequency of extreme events in the 1990sgenerally are less than the observed initannual variability,but the changes become very large within the next fewdecades The large effects are not a result of unusual localresults in the model's computed AT. The computed warmingin the United States are typical of other land areas in themodel. For the case of doubled CO, which we can comparewith other models, the warming we obtain in the UnitedStates (about 431C, we paper 2) is intermediate betweenthe warnings in the GFDL (Manabe and Wetherald, 1987)and NCAR [iWashingfon and Meehl, 19841 models.

Even small temperature changes, less than the interannualvariability, can be noticeable to the "man-in-the-street" andhave significant Impacts on the biosphere. As one measureof the detectability of local greenhouse warming, weconsider the frequency of warm summers. We arbitrarilydefine the 10 warmest summers (June-July-Augus) in theperiod 1950-1lI9 as *hot", the 10 coolest as "cold, and themiddle 10 as normal*. The impact of the model-computedwarming on the frequency of hot summers is illustrated inFigure 6 for the region of Washington D.C., based on thefour gridboxes coveing the eastern pan of the UnitedStates, and for the region of Cmaha, based on the fourindependent west-central gridboxes In both regions by the1990's the chance of a hot summer exceeds 50-, in all threescenarios, and exceeds 70% in scenario A.

With hot, normal and cold summers defined by 1950-1979observations as described above, the climatological proba-bility of a hot summer could be represented by two faces(say painted red) of a six-faced die. Judging from ourmodel, by the 1990s three or four of the six die faces -il]be red. It seems to us that this is a sufficient 'loading" ofthe dice that it will be noticeable to the "man-in-the-street'. We note, however, that, if say a blue die face isused for a cold summer, there is still one blue die face inboth the 1990s and the first decade of the next century.Thus there remains a substantial likelhood of a cold seasonat any given location for many years into the future.

We concluded above that the magnitude of global meangreenhouse warming should be sufficiently large for sden-tific identification by the 1990s. We infer from thecomputed change in the frequency of warm surimers thatthe man-in-4he-street" is likely to be ready to accept thatscientific condluslon. We also conclude that, if the worldfollows a course between scenarios A and B, the tempera-lure dng within several decades will become largeenough to have major effects on the quality of life formankind in many regions,

The computed temperature ranges are sufficient to havea lr Impoa on other parts of the biosphere. A warmingof OC/decade implies typically a poleward shift ofisotherms by 50 to 75 km per decade. This is an order ofmagnitude faster than the major climate shifts in thepaleodimate record, and faster than most plants and treesare thought to be capable of naturally migrating [Davis,19 . Managed crops will need to be adapted to more

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extreme conditions in marty locales. For example. followingthe sugestion of S. Schneider (private communication). weestimated the effect of greenhouse warming on the likeli.hood of a fun of five consecutive days with maximumtemperature above 9S'F. Observations at Omaha, Nebraskafor the 30 year period 1950-1979 show 3 years/decade withat least one such run of 95F temperatures, With thewarming from our model this becomes S year/decade in the1990s in scenario A (4 years/decade in scenarios B and C), 7years/decade in the 2020 in scenario A (6 years/decade inScenario B and 4 yars/decade in scenario C), and 9years/decade for doubled CO1. Such temperature extremesare thought to be harmful to corn productivity (Meams et., 1964); thus these results imply that the impact on crop.

can be very nonlinear with increasing nean temperature.Another example of noninew response by the biosphere toincreasing temperature is evidence that many coralpopulations apell thek symblotic algae when watertemperature rises above about 30 leading to death of thecoral if temperatures remain in that range, As evidenced byrecen events in the tropics (Robeu, 19e7).

Negative Impacts of greenhouse warming on the biosphereare undoubtedly greatest in regions where species are doseto mnlmuM-temperture tolerance limits. Such impacts mybe at least partially balanced by improved opportunities forproductive ife in other regions. Also the "fertilization'effect on crops due to increasing atmospheric CO. Plio"n,1963) and other greenhouse climate effects such as changesin precipitation Mfanabe and Wetheou/d, 1967) may haveimpacts besides that of the temperature change. Ourintention here is only to show that temperature changesthemselves can have a major impact on life, and that theseeffects may begin to be felt soon. We emphasize that it isthe possibility of rapid climate change which is of mostconcern for the biosphere; there may not be sufficent timefor many bioytems to adapt to the rapid changes forecastfor scenarios A and B.

6. DiSCUSSlONOur simulations of the global climate response to realistic

imeedependen c s of atmospheric trace gases anderosols yield the following results. (1) global warming

within the next few decades at least to the maimum levelsachieved durng the lat few interglacial periods occurs forail the trace gas scenarios which we consider, but themagnitude of further warming depends greatly on fituretrace gas growth rues; (2) the global greenhouse warmingshould rise above the level of natural climate variabilitywithin the nemt several yeas, and by the 1990s there shouldbe a noticeable increase in the local frequency of warmevents; (3) some regions where the warming should Oeapparent earliest are low latitude oceans, certain continentalareas, and sea Ie regions the threedimensional pattern ofthe predicted warming Is model-dependent, implying thatappropriate observations can provide discrimination amongalternative model representations and thus lead to improvedclimate predictions; (4) the temperature changes are

sufficiently large to have major impacts on man, and hisenvironment, as shown by computed changes in the fre-quency of extreme events and by comparison with previousclimate trends; (5) some near-term regional climate varia-tions are suggested; for example, there is a tendency in themodel for greater than average warming in the Southeastand Central U.S. and relatively cooler conditions or lessthan average warming in the western U.S. end much ofEurope in the late 1900s and in the 1990s.

In this section we summarize principal assumpfions uponwhich these results depend. In the final subsection westress the need for global observations and the developmentof more realistic Models.

6.1. Climate Sensiiw4The climate model we employ has a global mean surface

air equilibrium sensitivity of 42T for doubled CO. Otherrecent OCM's yield equilibrium sensitivities of 2,5-5.5C, andwe have presented empial evidence favoring the range2.5-5-C pwp 2). Reviews by the, National Academy' ofSciences [Chanme, 197, Sm qon , 1982) recommendedthe range 1.54.3C, while a more recent review byDic w n 11966) recommended 15-5.5C.

Forecast temperature trends for time scales of a fewdecades or less are not very sensitive to the model'sequilibrium climate sensitivity (Han uis v a.t, 1985)Therefore climate sensitivity would have to be much smallerthan 4.2C, say ..5-21C, in order to modify our conclusionssignificantly. Although we have argued lpaper 2) that sucha small sensitivity is unlikely, It would be useful for thesake of comparison to have GCM simulations analogous tothe ones we presented here, but with a low climate sensti-vity. Until such a study is completed, we can only statethat the observed global temperature trend is consisentwith the high" climate sensitivity of the present model.However, extraction of the potential empirical informationon climate Sensitivity wili require observations to reduceother uncertainties, as described below. The neededobservations include other climate forcing and key climateprocesses such as the rate of heat storage in the ocean.

61 Climate ForingpClimate forcing due to Increasing atmospheric greenhouse

gases in the period from 1958 to the present is uncertain byperhaps 2D% (Appendix B); the uncertainty about futuregreenose forcing is considerably greater. Therefore ourprocedure has been to consider a broad range of trace gasscenarios and to provide formulae (Appendix B) which allowcalculation of where the climate forcing of any alternativescenario fits within the range of forcing defined by ourscenarios A, B and C.

We emphasize that as yet greenhouse gas climate forcingdoes not necessarily dominate over other global climateforcing. For example, measurements from the Nimbus 7satellite show that the sola irradianc decreased by about0.1% over the period 1979 to 1985 [Wilson et at., 1986.

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Frohlich, 1987). As shown by formulae in Appendix B. thisrepresents a negative climate forcing of the same order ofmagnitude as the positive forcing due to the increase oftrace gases in the same period. The obsved trend impliesthe eaience of significant solar rradiance variations ondecadal time scales, but does not provide information over asufficient period for inclusion in our present simulatiorts.The greenhouse gas forcing has ireased more or lessmonotonically, at least since 1958; thus the greimhouse gasclimate forcing in the 1960s including the *unrealize"warming [He.un ei at., 19851 due to gases added to theatmosphere before the 19W0s probably exceeds the solarirradiance forcing. unless there has been a consistent solartrend for two decades or more. If the solar radiancecontinues to decrease at the rate of 1979-195 it couldreduce the warming predicted for the 1990s on the otherhand, if the decline of solar irradiance bottoms out in thelate 1980's, as recent date suggest [Hickey t al., 1967, andif the irradiance begins an extended upward trend, t ispossible that the rate of warming in the next decade couldexceed that in our present scenarios. Continued monitoringof the solar irradiance is essential for interpretation ofnear-term climate change and early identification ofgreenhouse warming.

Stratospheric aerosols also provide a significant globalclimate forcing, as evidenced by the effects of Mt. Agung(1963) and El Chich6n (1982) aerosols on our computedglobal temperatures. Thus, if a very large volcanic eruptionoccurred in the next few years, it could signficantly reducethe projected warming trend for several years On theother hand, if there are no major volani eruptions in theremainder of the 1980s or the 1990s, that would tend tofavor more rapid warming than obtained in scearios B andC, which asuumed an eruption in the mid 1990s of themagnitude of El Chlch6n. Interpretation of near termclimate dce will require monitoring of stratosphericaerosols, as well as solar irradiance.

Other climate forcing, such as changes in troposphericaerosols or surface albedo, are also potentially significant(Appendix B), but probably are Imponrtan minily on aregional basis. Examples of changing awol abundanceinclude the arctic haze, long-ring transport of desertaerosols, and perhaps urban and rural aerosols, of anthro-pogenic origin. Signlicaa surface aMedo variaclns may beassociated with large scale deforestation anddbut available information on trends Is not ufidentyquantitative for inclusion in our global simulations. It isdesirable that calibrated longterm monkoring of tropo-spheric aerosols and surface albedo be obtained in thefuture.

6.3. Ocean Heat SnW and TmnprOur ocean model is based on the assumption that, for the

small climate forcing of the past few decades and the nextfew decades, horizontal transport of heat by the ocean willnot duge significantly and uptake of hem perturbations bythe ocean beneath the mixed laye will be at a rate similar

to that of passive tracers simulated as a diffusive processWe believe that these assumptions give a global result whichis as reliable as presently possible, given available know.ledge and modeling abilities for the ocean; in any cas thisapproach provides a firs result against which later resultsobtained with dynamiclly interactive oceans can becompared.

However, we stress that our ocean model yields relativelysmooth surpris-free temperature trends. It excludes thepossibility of shifts in ocean circulation or in the rate ofdeep water formation. There s evidence in paleocimaterecords that such ocean fluctuations have occurred in thepast PIecker er at., 1985), especially in the North Atlantic.where, for example, a reduction in the rate of deep waterformation could reduce the strength cf the Gulf Stream andthus lead to a cooling in Europe. We caution that ourocean model usumptions exclude the possibility of suchsudden shifts in regional or global climate.

We also atress the importance of measuring the rate ofheat storage in the ocean. As discussed above and byHansen et at. 11965), on the time scale of a few decadesthere is not necessarily a great difference in the sur-face temperature response for a low climate senitivity (sayl3-2'C for doubled C02) and a high climate sensitivity(say 4-SC for doubled C02). However, the larger climatesensitivity leads to a higher rate of heat storage tn theocean Since theoretical derivations of climate sensitivitydepend so sensitively on many possible climate feedbacks.such as cloud and aerosol optical properties I$Svenill oandRemtr, 1984; Chadson er al., 1987), the best opportunity formajor improvement in our undersanding of climate sensi-tivi is probably monitoring of internal ocean temperature.Such measurements would be needed along several sectionscrossirg the major oceans. In principle, the measurementswould only be needed at decadai intervals, but continuousmeasurements are highly desirable to average out the effectof local fluctuations.

6.4 h" Can'ditom

Because of the long response time of the ocean surfacetempermure, the global surface temperature can be insubstantial disequil'brium with the climate forcing at anygiv time. By iiating our experiments in 1958 after aIong control run with 1938 atmospheric composition, we

lmpl.ct.q sim that the ocean temperature was approd-matdy in equilibrium with the initiil atmospheric composi-tion. Our results could be significantly modified by adifferem assumption. For example, if there were substantialunrealized greenhouse warming in 1938 due to a steadyIncrease of greenhouse forcn betwe the 1IOs and 1938.inepol of that disequlbrium in our initial conditionswould have caused the global temperature to rise faster thanit did in our aperimets. We Iniited our experiments in1938 principally because that is when accurate CO2 measure-mna began. However, 19$8 also appears to be a goodstarting point to minimize the poss'biity of a major dis-equilbrium between the initial ocean surface temperature

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and the atmospheric forcing, Global temperature peakedabout 1940 and wm level or defined slightly in the twodecades between 1940 and 19. Regardless of whether the1940 maimum was an unforced fluctuation of temperature ordue to a niesmum o some climate forcing, one effect ofthat wsnm period is to reduce and perhaps eliminate anyunreahzed greenhouse warming In 1958.

It would be useful to abo carry out smulatons whichbegla in my the 100, thus reducing uncertainties due topossible diequlibrim b the aita conditions Theseexperimenta would be prtloulauy appropriate for etractingempirical information on climate sensidt from theobserved warming I the peat century. Such experimentswr beyond the cpablity of our computer (crca 1975Amdahl). Moreover, because of greater uncertainties inclimate forcing before 1958, such experiments probablywould tot yield more reliable predictions of future climatetrend.

6.3. SmmayOur model results suest that globl greenhouse warming

wil soon rise above the level of natural dimate variability.The single beat pace to search for the greenhouse effectappears to be the global mean surface air temperature. If Itrises and remains for a few years above an appropriatesWlfmcance level, which we have argued is about 0AOC for99% confidence (3o). it will constitute convincing evidenceof a catse and effect relationship - a *smoking gn'. inoarrens vernacular.

Confirmation of the global warming will enhance theurgency of innumerable questions about the practical impactsof future climate change. Answers to these questions willdepend upon the details of the tiig maitude sad globdistribution of the changes o( many dbme parametersinformation of a specificity which cam presently beprovided. Ma)or improvements are needed in our under.standing of the climate system and our ability to predictclimate chnge

We condude that there is an wmu need for Ilbalto bpove knowledge of climate forcing

nmedianans ad climate feedback procents. The expectericlimate changes in the 1990 present at once a greatscientific opportunity, because they will provide a chance todisctiminate among aternative model representations, and agreat mentifc chaDllenge, because of demands that wM be

nerated for improved climate ment nd prediction.

Apastx A: OCAN MoDEL AND OcuA DATAThe sasonal transport of heat in our ocean model is

specified by the cnergence (or divergence) of heat at cocean gripoint, determined from energy balance as thedifference between the time rate of change of heat storageand the heat flux at the air sea interface. The heatstorage is calculated from the Robinsom ad Burr 11981)ocean surface temperatures, the Northern Henisphere

horizona Ice men of W&M st d Jknuron 119791. theSouthern Hemispere Ice ment of Aamnder and Mobley(1974t, and mixed layer depth$ cmp from NODC bathy.thermograph data 1NO4A, 19741. Te surface heat flux wassaved from a two year run Of Model H Loqsr 1) which usedthe above monthly ocean sufe temperature as boundaryconditions. Figure 1 of pqw, t2 eoalm this surface heatfhux. The eailoulatlon of the ocean heat transport bsdescribed , a, L b.&. aL.IS.whoeFIgure 5 shows the geographical distribution of the mixedlayer depths for Februay and August. The global area.weighted vaw of the annual maximum mixed layer depth is127 m.

The gose characteristics of the ocean surface heat fluxand implied ocean heat trampon appear to be realisic, withbeat pin and flux divergence at low laitudes, and heMat lossand flux convergence at high latitudes. A comprehensivecomparison of the annual ocean heat transport by Miller eta. (IM)3 shows that the longitudinally integrated transportin each ocean basin i consistent with available knowledgeof aual traUpo

In our 100 year conrl run, there Is no achxa,- of heatat the base of the mixed layer. In the experiments withvarying atmoqhri composition we mimic, as a diffusionprocess, the flux of temperature anomalies from the mixedlayer into the thermocla. The theimochne, taken to bethe water below the annual maxinum mixed layer, isstructured with eight layers of gtometrcally increasingthickness, with a total thickness of about 10(0, m.

An effective diffusion coaficient, k. is estimated belowthe annual mlmum mixed layer of each ridpoint using anempirical relation between.the penetration of transient inerttracers and the lcal water column *abiy Vqw 2J, thelatter ben obtained from the annual amen desitky distri-bution calculated from Ltrna 119121. The resuming globaldistribton of k isnshowsn In Itur le o p4per 2 Therein a low exhange rate (k a 0.2 ctn/sec) at low latitudesand a high exchange rate in the North Atlantic andsouthern oceans where connective overturning occurs, Notethat kin constantt h time and in the vertic direction.

The ocean temperature and the omen ice state in thetransient aperments ar compued baed on energy balance.The specied converged , ean hea and the diffusion intothe thmod,,e wre deposited into or removed from theactve mied layer. The surface fhax beats (or cools) the*pan ocean and own Ice in proportion to their exposedares. In addition there is a vertical exchange (conduction)o heat bet the oca and the le above it.

When the surface flus would cool the mixed layer below-1IOC, the mixed layer stay at -I0C and ice with 1 mthickness is formed rowng horbontsly, at a rate deter.mined by energy balance. When the surface fluxes wouldwarm the ocean above M'C the ocean stays at 0C until allice in the gdx. ik melted horizontally. Conductivecooling at the ice/water interface thidtens the ice if theocean temperaure is at -lOC. Lads are crudely repre-sented by requiring that the fraction of open water in a

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fpidbox not be less than 0./Izi where zm is the Icethickness in meters Looper 1).

APPEM B. RAmA1nvE FOCm sRadiative forcing of the climate sstem can be specified

by the global surface air temperature change ATo that wouldbe requbed to maintain enerVy balance with space' if noclimate feedbacks occurred Loqw 21. Radiative forcing fora variety of changes of climate boundary conditions arecompared in Figure Bl, based on calculations with a I-Dradative.conev (I.D RC) model VLds et u., 19 1.The following formulae approtomate the AT, from the I-DRC model within about 1 percent for the indicated ranges ofcomposition. The absolute accuracy of these forcing Is ofthe order of 10% due to uncertainties in the absorptioncoefficients and appradmations in the I.D calculations.

Co2: AT(X) - R(s)- R(;f(x) - In (1 + 1 + 0.00.5, + 1.4x10"60);

x0 -315 ppmv, x s 1000 ppmv

CCI2F2: AT,(x) - 0.084(s-x,); x-x, s 2 ppbyCCI)F: ATo(x) w 0.066(x-xo); xs-x, s 2 pptv

C H4: AT * - g(xy) -S(i.y )N20: AT. - g(x,,y) -g(x,,y,)

where0-66 0,,

(,y)-0. 394x .16'6sC *1.556In +V (109.8,3k.5l1+0.169x0-62 100 + 0.1y J-0.014 In 11 +0.636(xy)0. + 0.007x(xy)-);

H2SO4 aerosols (20km): ATO(Y) a .5.8t; r (A - 501nm) s 0.2

H2S04 aerosols (0-2km): AT,(,) - -6.5,; (A a 530nm) s 0.2

Solar irnadiance:

Land albedo:

AT,(x) - 0.67x; x a aS.(%) s 1%

ATo(z) - -0.12n;x a A afedo of land area s 0.1

Troce St setnahosTrace gas trends beginning in 1958 (when accurate

measurements of CO2 began) were estimated from measure-mert data available in early 1983 when we initiated ourtransent simulations. References to the measurements aregiven in Shant&s md Hoffnan 11967. Figure B2 summarithe estimated decade bicrements to global grehouseforcing. The forcing shown by dotted in in Figure B2are speculatdve; their eflact was Included in scenario A, butecluded in scenarios B and C. The CHi forcing in the 1960srepresents a 1.5% yr't growth rate; recent data (Balk at af.,19661 suggests that a 1.1% yr" growth rate probably ismore realistic.

Specifically, in sonrio A CO2 Increases as observed byKeeing for the interval 1958-1961 Keeing er at., 19621

and subsequetly with 1.5% yr5i growth of the annualincremen,. CClVP (P) and CC1-F2 (F2) emissions arefrom reported ratm (CMA, 1962) and assume 3% yr5 tincreased emission in the future, with atmosphere lifetimesfor the gases of 75 and 150 years, rescively. CH4, baedon estimates give by Loas et at. 119611, increases from 1.4ppb In 1958 a a rae o 06% yr until 1970, 1% yr" inthe 1970 and 1.5% yrt thereafler. NO increasesaccording to the ensl-empirical formula of Weiss (19811.the rate being 0.1% yr in 1938, 0.2% yr-t in 1980, 0.49t yr-in 2000 and 0.9% yr 1 in 2030. Potential effects of severalother mce Pa (such as O. stratospheric HO, andchlorine and fluorine compounds other than CCI3F andCCiF 2) ar approinmed by multiplying the CCI3F andCCIF 2 amounts by two.

In scenario B the growth of the manual increment of COIs reduced from 1.5% yr. today to 1% yr1t in 1990.0.3% yrl in 2000 and 0 In 2010; thus after 2010 the annualincrement in CO is constant, 1.9 ppm yr*2 . The annualgrowth of CC and CCIF 3 emissions is reduced from 3%yr*1 today to 2% yr" in 1990, 1% yr1t in 2000 and 0 in2010. The methane annual growth rate decreases from 1.5%yr3t today to 1.0% in 1990 and 0.5% yr't in 2000. N20increases are based on the formula of Weiss 11981l. butthe parameter specifying annual growth in anthropogenicemission decreases from 35% today to 2.5% in 1990,1.5% in 2000 and 0.5% in 2010. No increase are includedfor other chlorofluorocarbons, 03, stratospheric H2O or anyother greenhouse gases

In scenario C the CO. growth is the same as in scenariosA and B through 1965; between 1985 and 2000 the annualCO, increment is fixed at 1.5 ppm yr*'; after 2000 COceases to Increase, its abundance remaining fixed at 368ppm. CC F and CCF, abundances are the same as inscenarioa A and B until 1990; thereafter CC43F and CC3Femission decree Unearly to zero in 2000. CH. abundanceis the same as in scenarios A and B until 1980; between1960 and 1990 is growth rate is 1% yr't; between 1990 and2000 its growth me is 0.5% yr t ; after 2000 CH4 ceases toIncrease, its abundance remaining fixed at 1916 ppb. As inscenario B, no increases occur for the other chlorofluoro-caibons O, stratospheric HIIO or any other greenhousega"

Sawsoep4aic deosc enariosTIe Tiative forcing due to stratospheric aerosols

depends principally upon their optical thickness at visiblewavelengths, their opacity in the thermal infrared region,and their global distrbution. Because of the small size ofklglived smospheic aerosols, their effect on planetaryalbedo generally eceeds their effect on infrared trans-.mission (i.s et at., 19603. Thus the most importantaerosol radiave parameter Is the optical thicuess atvisible wavelengths, i. We base the estimated i before ElChichfn primal on solar transmission measurements atMauna Loa (Mendonca, 1979) together with calculations with

12

89-338 0 - 88 - 3

I' .

62

a thre&4dmensional tracer model Rui amnd Low, 1981).The measured optical depth at Mauna Lo after subtrac-

tion of the mean 1958-1962 value which is assumed torepresm the local background vsaue, is shown as the lightline in Figure B3. An wbtrs mount of toce substancewas introduced in the straosphtere of the tmceir model atthe time and location of the voamic eruptions; of Agng(1963), Awu (1966), Femmndina (1968) and Fuego (1974).The computed mount of tcm at Mauna LoA was thenmultild by the coe facor required such that thecomputed tranmission eualed the mean measured trans-

ison at Mauna Los in the two yea following theeruption; the modeled aerosol opacity is Illustrated by theheavier line in Figure B3. The tracer model thus definedthe global distribution of aerosol optical depth for the-a 1958-1979.The aerosol optical depths for El Ch.ch6n. based on early

reports (Mc.ormic private communication), later publishedby McCeomsic e a.. 119641, were specified u follows, Forthe fti six months after the eruption'the opacity wasuniformly distributed between the equator and 301N.increasing linearly from -0 mat the time of eruption to1-025 three months after the eruption and remainingconstant for the next three moths Subsequently theopacty was uniform from 90N to 30 AJ and from W'N to9M"5 but with two times greater v in the northern regionthan in the southern region. Deginning 10 months after theeruption v decayed eponetally with a 12 month timeconstant.

The optical properties of the atmospheric aerosols before192 are based on measurements of A4ng aersols. Theshe distribution we used is that given by Toon mci Pollack11976), which is based on measurements by Mone, 119641; ithas mean uffective radius and viriance (Hmten and Tans,19741 of r,, a02am and vs w 0 .6 . These arosols areassumed to be sp wes of alf'uric add solution (75% acd byweight) with refractive Ws given by Palm'er ad WW't itj(1975. We used aze data for the El ChIch6n aerosolbased on measurements of Hoffma md Rosen 119)3. heirMay 1982 data had rg a IAsm, vg a 0.4, while theirOctober 1962 data had r, - 0.5a m, vat a 0.15. WeInteapolated linearly beee these two size distributions forthe sk month period AWl 1982 to October 1962 andthereafter used the ana particle (October 1962) medistribucio. These various size distributions yield the samecooling at the anh's surface as a function o r (A -SS0nm), within a few perem a computed with the I-D RCmode but the lg particles um a greater srospherichea4 For example, sh May 1962 distribution yields awarming of "C at 2km, the October 1982 dimonyields C, nd the Mossop [1964) aerosolabylds 1.S'C.

An emenav measurement campaign was mounted afterthe El Chldw6n erupton in 192, which will allow a moreprecise calculation of the geographical and akiute distr-bution of the radiative fordng than for any previousvolcano. We ar working with J. Pollack and P. Mc~ormick

to make use of the ful data now available for a comprc.henslive study of the climate Impact In that periodHowever, the scenarios in our present simulations wcredefined in early 1963 when only sketchy data on the ElCbchdn aerosols was eailable, so the uncertainty in theserosA., forcing after EJ Chchdn in our present simulationsis comparable to that in the prior yas

AcAxow*4tmc. We thank Jim Angell. Alan Robock and SteveSchneider for comments oa the rM draft of this paper, PatncePalmer and Jeff Jonas for helping produce the color figures, JcseMendosa for daftin other figu, and Carolyn Paurowski fordeastOp typesetting. Thl work has been st nocd by the NASAClimate Program sd EPA pant RM12962-0

13

63

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14

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is

65

Time (years)

Fi& 1. fobakma anwaua m su zrlfmsa p m p uwed i tke 10 year contzN run.

0

..U)

100

66

1.5 ... .. ' ... , " , , , , ",

COE forcing1.0Scenario

A-Q 5 " ......... . . v' ......................

0

2 .0 - C O & tr ce gses

1.05-e CI

m1.0 Roonothon ot al. (1985)

1.5 C 01 trace goes + OerosoltT

f.5.

-0.5 J ,i90 1980 2000 2020 2040

Date

]Fig. 2. Greenhouse rom" for trc ga scmndzo A, B and C as described in the text. ATO is the equilibriumi green-house warming for no climate feedbacks. 7Ue doubled CO= level of forng, ATo tv 1.M*Co¢€vZ when the C02 andtrace Sa ade after 1958 provide a forcing equivalent to S]ou;lint COl from 35 "pm to 63D ppl . The CO,, + tracepas fordngi estimted by PmwMmdm er a/. 11965] for 203D is also iUUSIratco.

I ~.

67

Est I m T .mpe ..ur .uI Annual Mean Global TemDeroture Chonae

Estimated Temperatures During , .

Altithermal and Eemion Times

1.0-v

4 4T

Timee

05d

IV

I V VV

sxt.Q. , 0 C ..... 9 .....

1970 1980 1990Dote

v v v2000 2010 2019

(0)

(b)Fig. 3. Annual mean global Surace air temperature computed for scenarci A, B and C Observational data is fromHanse and Lebedeff 11987, 1968). The shAded range in per (a) k an estimate of global temperature during the peak ofthe current and previo interglacial periods, about 6.000 and 10,000 years before parent, respectively. The zero pointfor observations is the 1951-1960 mean [Hansen and Lebedff, 1967); the zeo point for the model is the control runmean.

1.T

0)0

V1960

iL

2

68

I I-- Control Run

Maximum T

January*Oa 0*

S

a a i~ I ~

-20 -IS -10 -5 0 5Ton (C)- Trees (C)

10 15

-10 -5 0 5 10 I5 20-25-20 -15 -10 -5 0 5 10Tool, (°C)- TOOS(OC) (C ) Tmnin (*C)-Troin (TC)

2C(d)

Fig. 4. Distribution of daily maximum and daily minimum temperatures in January and July for 10 gridboxes(latitudes 310N to 470N, longitudes 759W to 125"W) approximately covering the United States. The solid line representsyears 92-100 of the control run and the dotted line If for years 205-20-39 of scenario A. The mean temperature ateach gridbox Is subtracted out frui, before computing the mean distribution for the 10 gridboxes.

5FUS..

4

I-9

2

CL

.C

tl,.J = -=m • - - . . .. _

69

Ns P V" with T'B0oFI3S°CI Dols W' Vow ith T ,,75?5F1-24*Cso

49 Washington, D.C.

CIm- A BC ABC AC A C0ome- ABC ASC AC Ata IM 890. 0'o s s olo M oa e 0 i 90 1004 Bobo's UK's

tslAg .90.100

Dy$ pW %lew tiM To 329F WC)

Aimo-ABC ABC AC AO0 9 60's i O100. ' 0*0.

New~ ~ Y~ k ........ .... .........New Yor k

AC A Cim- AB0 C A BC A C A Cio-AB8C AB C Aa0e0's am'os "Y 0906 aMO. Ro05* MSCI fsoqg 99.900 .solo's 00

to

Memphis

CimZ- ABC ABC1 AC A 10- AB A1L AC A,bo 1. 0 Moo. bo, s "Y ... S 0... .M..

CWO.nAC ABC AC A CAm-AB; A.CACtog oly"s SW solo 06 '@s Wolm mo I o'

I IC

1114011 80 6,1 1010'

rig. S. Oimaoloi and m del-bad estimates of future frequeacy of extreme temperature in several cis specifically.days with maximum temperature above 937 (3MC). days with minimum temperature above 7F5 (a 24C). and days withminimum temperature below XP (O*). Oimatolo is for the three decadeA, 1950-1979, the long and short bars (andthe dotted ad dalsed Ir'satal lines) specify the intermual and inierdecadal variability (standard deviation), reaped-tively, for these 30 years of data A. B and C represent trace ps scenmio A, B and C The vertical scale for dayswilh T s 3F(0 Is a etor two less than the scal for the other two quantities.

AC¢Wo, I 801'

70

Frequency of Hot Summers100... . . "

90 (a) Washington D.C.

80

601..

a: 50

.. 40 / S

30 - ,,o.". Scenario,

20-S ni10

90- (b) Omaha

8 0 .. .... .

70 ....

90z 60, 20 50C.

SS6.Et s Scenario A

30- .... o ... Scenario B

shdd - Scenario C20-

10-

0 L , I ,

1960's 1990's 2020's 2050 'sDECADE

Fig. 6. Estimate of the probability of the summer being ohm, shown for two locations for scenarios A, 0 and C A"hot" summer is one in which the mean temperature exceeds a value which was chosen such that one-third of thesummers were *hot* in 1950-1979 observations. The estimated probability for hot summers in the 1990s; is shown by the

shaded region for the range of scenarios

71

Radiative ForcOw

0 Cl €€CC118 Ci 3N0 Is s S Tw iw. ,. te. efir CCt €IF1 le" 44" % 0( 0, "g0 l20-5"1 0-601 k dewI , ,,el

.0 01S4S1rt t10b* *U21044 lO-l US-506W In-lo e Now*"IO I weso.*-5l 5 , SO* m an t001i 1 15551 t-I I I 141S t, 011f at llI 16t01ll tit.O0l I

Fg Bl. Global mean radiative forring01 the climate syem for arbitrary changes of radiative parametes. AT,is the temperature change at equilbrium (t .*-) compuled with a I-D RC model (or the specified change in radiattveforcing parameter, with ao climate feedbacksinluded; AT mumt be multiplied by a feedback factor f go get theequilibrium surface temperaturechge including feedback 4f" paper 2. Tropospheric aero ar all placed inthe lower two kilometers of the atmosphere; the desert acrosi have effective radius rrw 2 um and single scatteringalbedo , 0.8 at wavelngth , aS50m, while the aoot aeooh have re w 1 u n and w 0.. The land atbedo changeof 0.05 is implemented via a change of 0.015 in the surface atedo corresponding to 30% land cover.

0.10DECADAL INCREMENTS OF GREENHOUSE FORCING

0.08 **et

0.06 03 *CFCs0 c s:* FC

0 -• .9 . ... . . . ... . . . .. . . ' . H C 0 2O = 2

1850 - 1960(per decade)

DECADES

F19 B2. Estimated decaal additions to global man greenhounseforing of the climate system. AT, is defined in theca m o Fft BI. Forciag shown by dotted lines are highly speculti.

105tikit,oott

72

0.04

Aerosol Optical Depth at Mauna Loa

0.03

f 0.02

g 0.01

0

-0.01 i I ,t, i fi I , I I 1 ,1960 1965 1970 1975 1979

Dote

Fig. B3. B Aerosl optical depth measured at Masum Lo (light line) after subtraction o( the mean value for 1958-1962.The heavy line is the optical depth at Mauna Los obtained from the three-dimensional tracer model, as dioud in thetext. Th arrowi mark the times of eruption ofAgn ng Awu, Fernandina ad Fucgo, respectively.

73

Plate 1. Interannual variability (standard deviation) of temperature in the 100 year control run (lcft side) and asestimated from observations (right sie) (a). (b), (c) and (d) show the interannual variability of surface air tempera.ture, and (e) and (f) show the interannual variability of the loogitude.integrated upper air temperature. (b) and (d) arebasud on 1951-1980 observation at meteorological nations analyzed by Hansen and Lettdeff 11967J. (1) is based on1958-195 radiosonde data analyzed byAnql/ 1966. Regions without data are black.

Plate 2. Left side: decadal mean temperalture chane obtained for scenario B, relative to the control run, for thedecades IO( 199t and 21OLW Right side: ratio of the computed temperature change to the interannual variability ofthe annual on temperature in the 100 year control mn (Plate a).

Plate 3. Left ade: decadal mean temperature ebane for scenario B as a function of latitude'and season, for thedecades 196 0 i99 and 2010L Right side: ratio of the computed temperature change to the interannual variability ofthe monthly mean temperature In the 100 year control run (Plate Ic)

Plate 4. LAft side: decadal mean temperature change for scenario B as a function of pressure and latitude, for thedecades 1960s, 199(k and 2010s. Right side: ratio of the computed temperature change to the Interannual variability ofthe annual mean temperature in the 100 year control run (Plate It).

Plate S. Simulated June-July-Augpus (left side) and December-Januaty-Fbruary temperature anomalies in the 1990, -compared to the 100 year control run with 1958 atmosphere composition.

Plate 6. Simulated July surface air temperature anomalies for six individual years of cenano B, compared to the 100year control run with 1956 atmospheric composition.

74

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80

Senator WIRTH. Fine. Thank you very much, Dr. Hansen. I thinkwhat we will do is run through the whole panel, if we might. If wemight then go in the order in which I introduced the witnesses; Mr.Oppenheimer, Mr. Woodwell, Mr. Manabe, Mr. Dudek, and Mr.Moomaw.

STATEMENT OF DR. MICHAEL OPPENHEIMER, SENIORSCIENTIST, ENVIRONMENTAL DEFENSE FUND

Dr. OPPENHEIMER. Thank you, Mr. Chairman. My name is Dr.Michael Oppenheimer. I'm an atmospheric physicist and senior sci-entist with the Environmental Defense Fund.

Mr. Chairman, it is hot out today and unless we change our waysof producing energy, as we have just heard, it is going to continueto get hotter.

I would like to thank the committee for giving us the opportuni-ty at this particularly appropriate time to testify about a recentreport developing policies for responding to climatic change, whichI will refer to as the Bellagio Report published two weeks ago bythe World Meteorological Organization and the United Nations En-vironment Program. I participated, along with Dr. Woodwell, inthe preparation of that report.

This project that led to the Bellagio Report was developed in thewake of the publication in 1985 of a report, sometimes called theVillach 1985 Report also by UNEP and WMO, in which experts onclimate from around the world produced a consensus that globalwarming, due to the emissions of greenhouse gases, was indeed un-derway. An examination of policy options was recommended. TheBellagio Report based on deliberations at two meetings by scien-tists and policy makers found that the time for action to respond tothe impending warming is now.

In particular the report recommends several steps to be under-taken immediately with the goal of slowing global warming. Othermeasures to cushion the consequences of unavoidable change andto develop a coordinated international response are also recom-mended in the report, including consideration of an internationalconvention or law of the atmosphere.

In my personal opinion greenhouse warming presents the mostimportant global challenge of the next fe.w decades on a par withdefense, disarmament and economic issues. With warming appar-ently now measurable, as we have just heard, we are already pJay-ing catch-up ball. The midwest drought is a warning. Whether ornot it is related to global changes, it provides a small taste of thedislocation society will face with increasing frequency if we fail toact. If measures are not undertaken soon to limit the warming,humans face an increasingly difficult future while many naturalecosystems may have no future at all.

To illustrate the magnitude of the problem, I was going to brieflydescribe the greenhouse warming. I'm sure most of you have heardabout it, so I don't need to repeat it. But it is due to the emissionsof a variety of gases into the atmosphere which trap heat and leadto a warming of the surface. Primary among those is carbon diox-ide. And remember also that the sea level will rise in lock stepwith the increasing temperature due to the expansion of the oceans

81

and the melting of land ice. As long as the amounts of greenhousegases increase in the atmosphere, this process will continue una--bated.There will be no winners in this world of continuous change,

only a globe full of losers. Today's beneficiaries of change will betomorrow's victims as any advantages of the new climate roll pastthem like a fast moving wave. There will be a limited ability toadapt because our goals for adaptation will have to change continu-ously. The very concept of conservation on which environmenta-lism in this country was originally built does not exist in a worldwhich may change so fast that ecosystems, which are slow toadjust, will wither and die.

The technical findings of-- the, Villach-Bellagio workshops includethe following. Global mean temperature will likely rise at about 0.6degrees Fahrenheit per decade and sea level at about 2.5 inches perdecade over the next century. As we have heard, the temperaturetrend will be more extreme at the higher latittudes. These, rates arethree to six times recent historical rates. By early in the' next cen-tury, the world could be warmer than at any time in human expe-rience. Furthermore, as long as greenhouse gases continue to growin the atmosphere, there is no known natural limit to the warmingshort of catastrophic change. Thus, at some point these emissionsmust be limited.

Because the oceans are slow to heat, there is a lag between emis-sions and full manifestation of corresponding warming, a lag whichsome estimate at 40 years. The world is now 1 degree Fahrenheitwarmer than a century ago and may become another 1 or more de-grees warmer even if conditions are curtailed today. These changesare effectively irreversible because greenhouse gases are long-lived.We cannot go back if we don't like the new climate. So, action toslow the warming must be taken before full consequences of cur-rent emissions are manifest and understood.

This already committed warming means some adaptation meas-ures such as sea defense and even coastal abandonment are inevi-table. But effective adaptation will be costly and for many nations,such as Bangladesh for instance, infeasible. In fact, it willbe infea-sible in some parts of the United States.

The natural environment cannot adapt effectively to such rapidchanges. The impending warming must be viewed as a disaster fornatural ecosystems. The mountaintop declines of red spruce in theeastern United States, for instance, which are generally ascribed toair pollution or local climatic variability, pale in comparison to thescope of change impending if warming continues. For instance, onemodel by Dr. Schugard at the University of Virginia predicts essen-tially biomass crashes in southeast pine forests Over the next 40years if warming continues with declines of up to 40 percent occur-ring over only decadal periods. The recent dispute over oil explora-tion in the Arctic National Wildlife Refuge may be beside the pointif the Arctic ecosystem, i-driven off the north coast of Alaska byclimatic change.

If climate changes rapidly, agriculture and water resources maybe stressed. Even if global food supplies are maintained, one needonly look to the current great plains' drought to see the humanand economic cost associated with hot, dry weather in the grain

82

belt. Weather of this sort we can expect with increasing frequencyin the future.

Although some change is inevitable and, in fact, appears t bealready underway, unacceptable warming is not inevitable if actibis begun now. Every decade of delay and implementation of green-house gas abatement policies ultimately adds perhaps a degreeFahrenheit of warming and no policy can be fully implemented im-mediately in any event.

The experts assessing this situation at Bellagio thought that thelimitation of warming to recent historical rates of about 0.20 Fahr-enheit per decade for some finite time would at least give societiesand natural ecosystems a fighting chance at adjustment. But un-limited warming at any rate is ultimately problematic.

I hasten to say that the foregoing picture in some sense is goodnews. The bad news is that climate change may not occilir smooth-ly. Rather, it could occur discontinuously which would render fruit-less any attempts at planned adaptation. The advent of the ozonehole should make us cautious in assuming that atmospheric changewill be gradual.

My testimony contains a list of policy recommendations from theBellagio Report, but let me make only one point. With permissionof the Chairman, I'll use the figure over here.

Slow warming at an acceptable rate-well, let me describe thesetwo curves first. The green curve is the current trajectory of green-house gases of carbon dioxide emissions projected into the futureand corresponds, roughly to case B, which Dr. Hansen was referringto befVre. The yellow curve represents an emissions trajectorybased on an attempt to slow warming to this point, 20 Fahrenheitper decade that I discussed before that would give us a fightingchance. It actually might ultimately stabilize carbon dioxide con-centrations in the atmosphere and climate change.

The difference between those two trajectories-what we are infor if we do business as usual and a trajectory that might stabilizethe atmosphere--I'll call the greenhouse gap. That's the gap thathas to be closed if we are to have a fighting chance.. That repre-sents about a 60 percent reduction of current carbon dioxide emis-sions and, unfortunately, perhaps an 80 percent reduction fromfuture emissions in the year 2025, just 40 years hence becauseemissions are projected to grow with business as usual.

As I said, given this projected doubling in emissions over thenext 40 years if we do nothing, we have a daunting task ahead. Itis a task we must begin today.

Thank you.[The prepared statement-of Dr. Oppenheimer follows:]

83

ENVIRONMENTAL DEFENSE FUND1616 P Street, NWWashington, DC 20036(202) 387-3500

Testimony of Dr. Michael Oppenheimer

before the

Committee on Energy and Natural Resources

United States Senate

p 23 June 1988

National Headquarters257 Park Avenue SouthNew York, NY 10010(212) 505-21001405 Arapahoe AvenueBoulder, CO 80302(303) 440-4901

5655 College AvenueOakland, CA 94618(415) 658-80061108 East Main StreetRichmond, VA 23219(804) 780-1297128 East Hargett StreetRaleigh, NC 27601(919) 821-7793

1v% "acych Pap.

/

I

84

My name is Dr. Michael Oppenheimer. I am an atmospheric

physicist and senior scientist with the Environmental Defense

Find, a private, non-profit organization. I would like to thank

the Committee for giving me the opportunity to testify about the

recent report, DEVELOPING POLICIES FOR RESPONDING TO CLIMATIC

CHANGE, (referred to hereafter as the "Bellagio Report"),

published by the World Meteorological Organization and the

United Nations Environment Programme. The Environmental Defense

Fund, along with the Beijer Institute of the Royal Swedish

Academy and the Woods Hole Research Center, was an originator of

the project which produced this report. I served on the

steering committee for the two international conferences which

provided the basis for the report, and I also contributed to its

preparation.

This project was developed in the wake of publication of

the report of the 1985 UNEP/WHO/ICSU Villach meeting in which

experts on climate from around the world produced a concensus

that global warming due to the emissions of greenhouse gases was

indeed underway. An examination of policy options was

recommended. The Bellagio Report, based on deliberations by two.

meetings involving scientists and policy-makers (called the

Villach 1987 and Bellagio workshops), finds that the time for

action in response to impending warming is NOW. In particular,

/

85

the report recommends several steps to be undertaken immediately

with the goal of slowing global warming. Other measures to

cushion the consequences of unavoidable change, and to develop a

coordinated international response, are also recommended,

including consideration of an international convention or "law

of the atmosphere".

In my personal opinion, greenhouse warming presents the

most important global challenge of the next few decades, on a

par with defense, disarmament, and economic issues. With

warming apparently now measurable, we are already playing

catchup bail. The Midwest drought is a warning: whether or not

it is related to global changes, it provides a small taste of

the dislocations society will face with increasing frequency if

we fail to act. If measures are not undertaken soon to limit

the warming, humans face an increasingly difficult future while

natural ecosystems may have no future at all.

To illustrate the magnitude of the problem, let me briefly

describe the causes of greenhouse warming. Certain gases which

occur in the atmosphere in small amounts are growing rapidly in

concentration due to human activities related to industry and

agriculture. Primary among these is carbon dioxide, a product

of coal, oil, and natural gas combustion. These "greenhouse

gases" trap heat radiating from the surface of the earth which

would normally escape into space, resulting in a warming of the

surface. This increase in global temperature causes a

concommitant rise in global sea level as ocean water expands and

86

land ice melts. As long as the amounts of greenhouse gases

increase in the atmosphere, this process will continue unabated.

There will be no winners in this situation, only a globe

full of losers. Today's beneficiaries of change will be

tomorrow's victims as the changing climate rolls past them like

a wave that first sweeps you up, then drops you in the trough

behind it. The very concept of conservation does not exist in a

world which may change so fast that ecosystems, which are slow

to adjust, will wither and die.

The technical findings of the Villach-Bellagio workshops

include:

Global mean temperature will likely rise at about 0.6

degrees Fahrenheit per decade and sea level at about 2.5 inches

per decade over the next century. These rates are 3 to 6 times

recent historical rates. By early in the next century the world

could be warmer than at any time in human experience.

Furthermore, there is no'known natural limit to the warming

short of catastrophic change, for as long as greenhouse gas

growth continues in the atmosphere. At some point, these

emissions MUST be limited.

Because the oceans are slow to heat, there is a lag

between emissions and full manifestation of corresponding

warming -- a lag of perhaps 40 years. The world is now 1 degree

F warmer than a century ago and may become another one or more

degrees warmer EVEN IF EMISSIONS ARE ENDED TODAY. These changes

87

are effectively irreversible because greenhouse gases are long

lived. WE CAN'T GO BACK IF WE DON'T LIKE THE NEW CLIMATE. So

action to slow the warming must be taken before full

consequences are manifest.

This committed warming means some adaptation measures,

such as sea defense and coastal abandonment, are inevitable.

But effective adaptation will be costly and for many nations,

such as Bangladesh, infeasible.

. The natural environment cannot adapt effectively to such

rapid changes. The impending warming must be viewed as A

DISASTER FOR NAfURAL ECOSYSTEMS. The mountaintop declines of

red spruce in the eastern United States, generally ascribed to

air pollution or climate variability, pale in comparison to the

scope of change impending if warming continues. For instance,

one model predicts biomass crashes in southeast pine forests in

the next century tf warming continues, with declines of up to

40% occurring over decadal periods. The recent dispute over oil

exploration in the Arctic National Wildlife Refuge may be beside

the point if the Arctic ecosystem is driven off the north coast

of Alaska by climatic change.

If climate changes rapidly, agriculture and water

resources will be stressed. Even if global food supplies are

maintained, one need only look to the current Great Plains

drought to see the human and economic cost associated with hot

and dry weather in the grain belt, weather of the sort which we

can expect with increasing frequency in the future.

88

Although some change is inevitable, and in fact appears

to be already underway, unacceptable warming is not inevitable

if action is begun NOW. Every decade of delay in implementation

of greenhouse gas abatement policies ultimately adds about a

degree F of warming; and no policy can be fully implemented

immediately in any event. Limitation of warming to historical

rates (about 0.2 degree F/decade) for some finite time would

give societies and natural ecosystems a fighting chance at

adjustment. But unlimited warming at any rate is ultimately

problematic.

. The foregoing picture is the good news. The bad news is

that climate change may not occur smoothly; rather it could

occur in jumps which would render fruitless any attempts at

planned adaptation. The advent of the ozone hole should make us

cautious in assuming that atmospheric change will be gradual.

Slowing warming to an acceptable rate and ultimately

stabilizing the atmosphere would require reductions in fossil

fuel emissions by 60% from current levels, along with similar

reductions in emissions of other greenhouse gases. Given the

projected doubling in emissions over the next 40 years (see

Figure 1) in "business-as-usual" scenarios, we have a daunting

task ahead.

Certain immediate policy responses can set us along the

path toward climate stability. Measures recommended for

immediate implementation include:

Ratification, implementation and consideration of

strengthening of the Montreal Protocol on CFC emissions.

89

. Development of national energy policies which encourage

efficiency in generation, transmission and use.

. Investments in research and development of non-fossil

fuel alternative energy systems.

• Encouragement of use of low-CO2 fuels such as natural

gas as a bridging measure.

. Control of nitrous oxide, methane and tropospheric ozone

emissions where technology is currently available (such as

tapping solid waste landfills for methane). Funding research

and development on control methods where uncertainties remain.

• Reversal of the current deforestation trend since

forests serve to store carbon which would otherwise aggravate

the geenhouse problem.

* Consideration of a global convention on greenhouse

gases.

• Planning for coastal protection and abandonment.

• Research support.for global change basic science

initiatives.

Policy research on "how to get the job done".

The United States government should take the lead now with

a series of measures in each of these areas. We still have a

window of opportunity to limit these changes to acceptable

levels. The development of these policies, their implementa-

tion, and the diffusion of these solutions to the rest of the

world, should largely define the framework for scientific and

technological development over the next few decades. Thus the

problem of global warming presents both challenges and

opportunities. But the pui uit of solutions and their

implementation must iegin today.

/

r""mF CARBON DIOXIDE EMISSIONS *

'Slow Chmm" scenario

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91

Senator WIRTH. Thank you very much, Dr. Oppenheimer.Dr. Woodwell?

STATEMENT OF DR. GEORGE M. WOODWELL, DIRECTOR, WOODSHOLE RESEARCH CENTER

Dr. WOODWELL. Thank you. I am George M. Woodwell, Directorof the Woods Hole Research Center. I wish to add strength to theassertions of the two previous speakers who have articulated thingsso splendidly and accurately.

We are embarked on a period of drastic climate change. We havelived through and developed our civilization in a period of substan-tial stability of climate. We are now entering a period when cli-mates globally will change substantially.

The rate of change is of particular importance. The averagechanges in temperature of the earth that you heard described justa few moments ago are, of course, made up of extremes. Thechanges in the tropics will be very little. The changes in high lati-tudes will be substantial perhaps two and a half times, maybe twotimes, the amount of change described as the average change inthe temperature of the earth or whatever amount of infrared ab-sorptive gas accumulates in the atmosphere.

The amount that is usually settled on is the equivalent of thedoubling of the carbon dioxide content. We expect that that wouldoccur sometime early in the next century, certainly before themiddle of the next century, 2030 or so. At that time the tempera-tures in the middle and high latitudes may be two times or soabove the means we have heard discussed. We expect the means torun for the earth as a whole somewhere between 1 and a half and5 and a half degrees Centigrade. So, we could have over the nextdecades changes in the temperature in the middle and high lati-tudes where we live and farther north, considerably farther north,that might approach a half a degree Centigrade to well over adegree Centigrade per decade. Those are very big changes meas-ured in any calculus.

They are much larger than the capacity of forests, say, to adaptto climatic change. Forests are easily destroyed and not very easilyrebuilt. A temperature change of the order of 1 degree Centigradeis the equivalent of moving northward under present climatic re-gimes roughly 100 to 150 kilometers. That would be 60 to 100 miles.That sort of change in a decade in the high latitudes is entirelyconceivable as something that can occur in the next decades. Thatchange has the potential for destroying forests over large areas ata high rate.

Now, why is that important? Well, it's important for several rea-sons, not the least of which is that we use forests very heavily, butalso because forests contain a large amount of carbon. It is con-tained in the plants of the forest and in the soils. There is in themiddle and high latitudes at least as much carbon stored in forestsand their soils as there is in the atmosphere at the moment.Warming the earth at rates approximating those described and an-ticipated for the next years has the potential for speeding the re-lease of that carbon by stimulating the decay of organic matter insoils much in excess of any potential for those forests for taking

92

carbon out of the atmosphere and putting it back into soils and thebodies of plants.

That's a positive feedback system that has not been worked intothe calculus. It's the kind of surprise that we can anticipate, thekind of surprise we have already observed in the ozone hole'ind inother aspects of global change. It has the potential for making theproblem substantially worse, a much more rapid change than wehave expected.

Well, these problems are big problems. The climatic change prob-lem is totally entwined in the energy problem, the challenge ofenergy policy, where we get our energy from and how we use itand how efficiently we use it.

It is also tied up in the population problem. We forget that in1950 there were just about half as niany people around as thereright now, and we have the potential for producing twice as manyby 2030 or thereabouts. There are 5 billion people in the world atthe moment. We use probably more than half of all the energy thatis fixed by green plants globally in support of those 5 billionpeople. What will we do with 10 billion? We have the potential, asDr. Oppenheimer just pointed out, of changing climatic zones, al-tering the productivity of agriculture and changing the potential ofthe earth for fixing carbon in green plants and changing it drasti-calleIfe can address these problems successfully-and I believe that

we can-we have the potential for a very comfortable and promis-ing future for the human enterprise. The problems unaddressedhave the potential for turning the world into a form of chaos notgreatly different from that produced by global war.

Let me show two graphs briefly to emphasize aspects of thisproblem that seem particularly important. This graph shows whatis probably the most famous set of geophysical data ever produced.On the left margin of the graph is the concentration of carbon di-oxide in the atmosphere. The abscissa, the lower margin that runsacross the bottom, starts in 1958 and runs through the 1980's. Theline shows the concentration of CO2 over that period. The datawere started by Dr. David Keeling of the Scripps Institution ofOceanography. I

You can see and appreciate the upward trend in the data. Thatparticular graph goes from about 315 parts per million on the leftto about 350 which is where we are right now. The upward trend iscaused by the net accumulation of carbon dioxide in the atmos-phere, carbon dioxide produced by burning fossil fuels and by de-stroying forests.

Now, there is probably a third component in that accumulationcaused by the warming itself, and that's this further componentdue to the decay of organic matter in soils. If the warming proceedsrapidly enough to destroy forests, that component can expand con-si era ly.

The second point I would make here is the oscillation. The peaksall occur at the end of the northern hemisphere winter. These datawere taken in the northern hemisphere at Maunaloa in the Hawai-ian Islands. The minima, those lower numbers, occur in each yearat the end of the northern hemisphere summer. We wondered formany years just why that occurred that way. We know now that

93

that's the metabolism, of forests which carry on a net of photosyn-thesis above the decay that I mentioned, above the respiration, andthat that is conspicuous during the summer. It pulls the carbon di-oxide content down globally. It actually 'pulls the carbon dioxidecontent down by 100 billion tons, which is about a seventh of thetotal amount of carbon in, the atmosphere each year, and it re-leases that back into the atmosphere annually through respirationleading to the peaks you see.

Well, a small change in the ratio of photosynthesis to respira-tion, the two fundamental physiological processes that determineheavily the balance of gases in the atmosphere, has the potentialfor changing the carbon dioxide content of the atmosphere. I makethis point simply to hammer home the scale of the influence ofliving systems on the human habitat and the scale of the influenceof forests in particular on the composition of the atmosphere andtherefore this climatic problem. There isn't a solution to the cli-matic change problem that does not consider the forests of theearth and other biotic systems.

If we could look at the second viewgraph which shows the samesort of data over a longer period of time-we are starting now wayback in 1740 and running through the 1980s-we see that upwardtrending curve is a characteristically exponential curve, the samekind of curve that population growth follows. It's a compound in-terest curve, a curve generated by a process that feeds on itself.Many, perhaps most, of the curves describing processes in naturefollow such trends.

That curve is being produced at the moment. Th-t upward trendis being produced at the moment by a net accumulAtion in the at-mosplee of 3 billion tons of carbon in excess of the amount that isabsorbed into the oceans and any other systems that absorb carbonincluding forests and other biotic systems. So, the net imbalanceright now is 3 billion tons. We release through burning fossil fuelsabout 5.6 billion tons. There is a further release destruction of for-ests in the range of 1 to 3 billion tons of carbon.

If there are other releases,- we are not able to measure them.There is probably a release due to the warming itself. We don'tknow what that is, but it doesn't matter. We do know that the im-balance is 3 billion tons right now.

If we could magically reduce the emissions by 3 billion tons, wecould instantaneously stabilize the composition of the atmosphere.It would be a temporary stabilization, very temporary probably,but nonetheless that is the scale of the challenge. It is well withinreach. We can do something about it.

What has to be donq? There isn't any question, no question inthe eyes of the group that met in the Villach and Bellagio meetingsthat Dr. Oppenheimer reported on, no question in the eyes ofothers who think about this problem. We must reduce the use offossil fuels on a global basis, a reduction of the order of 50 to 60percent is probably appropriate, and the sooner the better.

It is also true that cessation of deforestation on a global basis iscompletely appropriate to solve the climatic change problem andfor many other reasons.

It is possible to store carbon in forests by rebuilding forests, byreforesting areas around the world. The rate of storage is about 1

-9338- " 88 - 4

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billion tons for roughly 2 million square kilometers of forests. So, ifwe can start forests going over 2 million square kilometers, a verylarge area, that area will continue to store carbon at the rate ofapproximately a billion tons a year for 40 or 50 years as that forestgrows toward maturity.

Those three steps are clear and immediate. If we were lookingfor a single, simple signal policy that would lead the world-andwe must lead the world. We, the United States, are the global lead-ers. We have greater potential in that realm than any othernation, greater flexibility to take that sort of initiative-that stepwould be to establish a policy immediately of reducing our emis-sions of fossil fuels by 50 percent over the course of the next years,perhaps a decade or so. That objective is totally consistent withcontinued economic welfare. It is totally consistent with other ob-jectives in preserving environmental quality. It is totally consistentwith economic strength--

Senator MURKOWSKI. Are you prepared to recommend how,Doctor?

Dr. WOODWELL. How would we do that? Simply through conser-vation, through changing standards, for instance, of efficiency forautomobiles, by super-insulating houses, by building houses thatdon't require as much energy. And there are many, many ways ofdoing that.

So, I'm not at all doubtful that such an objective is realistic. Ifwe could establish that as a signal step in the process of reducingreliance on fossil fuel globally, I would think that we would havedone one of the strongest and wisest things possible.

Thank you.[The prepared statement of Dr. Woodwell follows:]

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TESTIMONY OF G.M. WOODIELLBEFORE TIM SENATE COMMITTEE ON ENERGY AND NATUL RESOURCES,

WASHINGTON, D.C.THURSDAY, JUNE 23, 1988

Rapid Global Warning:Worse with Neglect

I. Introduction: The Villach-Bellaqio Report

I am a scientist, Director of the Woods Hole Research Centerin Woods Hole, Massachusetts. I am also a member of the Board ofTrustees of the Natural Resources Defense Council, a conservationlaw group with more than 75,000 members around the country. Iappear before you in both capacities. My colleagues and I inscience have done research on various aspects of climatic changefor more than 25 years; my colleagues and I in the NRDC have madeformal efforts spanning nearly two decades to make betterconnections in public affairs between what we know and what wedo.

I am reporting on experience gained through two conferencesheld during the fall of 1987 in Europe dealing with climaticchange. The first was in Villach, Austria, and was a review byscientists of the details of the global climatic warming thatappears to be underway. The second, held in Bellagio, Italy, wasan exploration of the implications of the changes in climate forgovernmental policies. A report of these conferences has beenpublished by the World Meteorological Organization (WMO 1988) andis available to you. I am emphasizing in what follows the bioticinteractions involved in climatic change because thoseinteractions affect people most directly and have the potentialfor affecting the course of the climatic changes. I am alsogiving emphasis to the need for general solutions to the regionaland global problems that will become increasingly acute throughthe next years. I find it necessary to do so because we tend tooverlook the fact that 5 billion people now occupy the globe,twice the number present as recently as 1950. Before 2030 thehuman population could be 10 billion. The 5 billion we now haveuse half or more of the energy available from plants globally.Big changes in the humen condition will be occurring withoutclimatic changes. The climatic changes will compound thedifficulties in accommodating such extraordinary rates of growth.

II. A Consensus among scientists

Several points about climatic change now constitute aconsensus held by meteorologists and other scientists who haveworked on the problem. Most of these points have been made inslightly different form in the Villach-Bellagio report.

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1. The dominant influence on global climate for theindefinite future is expected to be a continuous warming causedby the accumulation in the atmosphere of infra-red absorptivegasses, especially carbon dioxide and methane, but includingnitrous oxide and the CFC's.

2. The warming marks the transition from a period of stableclimates to climatic instability. Stable or very slowly changingclimates have prevailed during the development of civilization.We are now entering a period of continuous warming accompanied bychanges in precipitation. The changes in climate are predictablein general at continental and broad regional levels; they are notpredictable locally.

3. The rate of the warming is uncertain. Estimates based onmodels suggest that a doubling of the carbon dioxide content ofthe atmosphere (or the equivalent through increases in othergasses) above the levels present during the middle of the lastcentury will produce a global average warming of 1.5-5.5 degreesC. Such an effect is expected by the period 2030-2050.

4. The earth has warmed between 0.5 and 0.7 degree C overthe past century and the rate appears to be accelerating.

5. The warming in the tropics will be less.than the mean forthe earth as a whole; in the middle and high latitudes thewarming will exceed the mean by two fold or more and will fall inthe range of 0.5-1.5 degrees C/decade.

6. The current sources of carbon dioxide are the combustionof fossil fuels and deforestation. The dominant source of methaneis anaerobic decay.

7. A rate of warming in the middle and high latitudes thatapproaches 1 degree C/decade exceeds the rate at which forestscan migrate and will result in the destruction of forests attheir warmer and drier margin without compensating changeselsewhere. Such destruction of forests and soils releaseadditional carbon into the atmosphere as carbon dioxide.

8. It is possible that the warming already experienced isstimulating the decay of organic matter in soils globally,increasing the total releases of carbon dioxide and methane.

9. No stimulation of the storage of carbon in forests orsoils that is large enough to compensate for such rapid releasesis known.

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10. The warming will cause accelerated melting of glacialice and an expansion of the water in the oceans. The effect willbe an increase in sea level of 30 cm to 1.5m over the next 50-100years.

11. The changes in climate anticipated over the next decadesextend beyond the limits of experience and beyond the limits ofaccurate prediction. Surprises such as the discovery of the polarozone holes are common in such circumstances. The possibilityexists that a rapid warming will change the patterns ofcirculation of the oceans and produce sudden but profound changesin climate in regions such as western Europe, now kept warm bythe Gulf Stream. The same changes may have equally surprisingeffects on the storage or release of carbon from forests andsoils.

The warming will move climatic zones generally poleward,shift the arable zones of the earth continuously, cause large andcontinuous dislocations of natural vegetation, and cause floodingof low-lying areas globally. The arid zones of the northernhemisphere will expand because there is more land at higherlatitudes in the northern hemisphere. The warming will begreatest in winter and will be accompanied by increasedprecipitation in high latitudes.

A one degree C change in temperature is equivalent to achange in'latitude of 100-150 km, 60-100 mi. Rates of warming, ifthey occur as anticipated over the next decades, will exceed thecapacity of forests to migrate or otherwise adapt. In thatcircumstance forest trees and other plants will die at theirwarmer and drier limits of distribution more rapidly than forestscan be regenerated in regions where climates become favorable.The destruction of forests will add further to the releases ofcarbon to the atmosphere. The seriousness of this problem willdepend heavily on the rate of warming. There is sufficient carbonin forests and soils of.middle and high latitudes to affect theatmosphere significantly. While there is no proof of this processand there will probably not be proof until the changes are wellunderway, the process will hinge heavily on rates of warming.Rates that approach 1 degree per decade exceed by a factor of 10or more the capacity of forests to accommodate the changes.

11. What Can be Done?

The earth will warm as a result of the changes in thecomposition of the atmosphere that have already occurred. But anopen-ended, continuous warming that speeds the rise in sea leveland destroys forests over large areas is so thoroughly disruptiveof the human enterprise as to preclude any thought thatcivilization might "muddle through". Can the warming be checked?

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The annual increase in the atmospheric burden of carbondioxide alone is about 3 billion tons currently. The globalwarming has the potential for increasing this net accumulation byspeeding the release of carbon from forests and soils withoutcausing an equivalent increase in the rate of storage. Noestimate is available of the extent to which this additionalsource of carbon dioxide is likely to compound the problem. Butthe new source will diminish as the warming diminishes.At least three possibilities exist for reducing or eliminatingthe imbalance and moving toward long-term stability of climate:

1. a reduction in the use of fossil fuels globally, nowestimated as the source of about 5.6 G-tons of carbon annually;

2. a reduction in or cessation of deforestation, nowestimated as releasing 1-3 G-tons annually;

3. a vigorous program of reforestation that wouldremove from the atmosphere into storage in plants and soils about1 G-ton of carbon annually for each 2x10° m tract in permanentforest.

Further adjustments in emissions will be appropriate asexperience accumulates. Such steps are appropriate now andpossible. They will bring widespread ancillary benefits to thehuman enterprise. Further delay increases the accumulation ofgreenhouse gasses in the atmosphere, the severity of the warmingthat must be accommodated, and the risk of unexpectedconsequences that lie beyond the limits of current prediction.

These changes are possible now. They will requireadjustments in the efficiency of use of energy in theindustrialized nations and imaginative and far-reaching changesin the patterns of development of the less industrializednations. Recognition of the need for the trariition to a new erain the management of the earth's resources opens newopportunities for industry and governments to pursue new pathsfor sustainable economic development on a global basis.

leferencos

WMO. 1988. Developing Policies for Responding to ClimaticChange. TD-No.225. World Meteorological Organization. 53 pp.

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Senator WIRTH. Thank you very much, Dr. Woodwell.We have been joined by Senator Chafee who is advertised as our

first witness this afternoon, and I had promised Senator Chafeethat as soon as he arrived-I know he has been involved in this fora long time. We are delighted to have you with us, John, and if youhave any kind of opening remarks or statement that you mightlike to make, please do so.

STATEMENT OF HON. JOHN H. CHAFEE, U.S. SENATOR FROMRHODE ISLAND

Senator CHAP. Well, thank you very much, Mr. Chairman. AndI want to commend you for holding these hearings, and certainlyyou have got a list of excellent witnesses. I apologize for not being

ere when I was meant to be. It is one of those days that we allhave where we are meant to be several places at once. But certain-ly there is no better time to hold these hearings than right now.

Destruction of the earth's climate system through the burning offossil fuel, as was just mentioned, and the release of manufacturedchemicals which I am sure will be touched on later, has been treat-ed as a distant threat or some kind of theoretical problem. But Ithink people are beginning to wake up to this. You can look atOcean City, Maryland and see the sea levels are already rising.The drought which we are enduring, particularly in the midwestand in the central part of the country, typifies the kind of changesin rain patterns that are predicted to occur as a result of the green-house effect.

If there is one point I could make, Mr. Chairman, it is this.There are a great many questions about the greenhouse effect thatcan't be answered today. But I don't think we ought to let scientificuncertainty paralyze us from doing anything. It is always conven-ient to find an excuse not to do something, and there's always anexcuse out there not to do something. But I think the issue beforeus is what steps should we be taking today to help solve the prob-lem in addition to doing more scientific research.

On March 31 of this, year, 41 Senators joined me in a letter tothe President urging him to call upon all nations of the world tobegin the negotiations of a convention to protect our global climate.And that proposal is under review, but the upbeat sign is we areseeing progress on the international level. This matter of the globalclimate change was discussed at both of the two meetings betweenthe President and Secretary Gorbachev here in Washington and inMoscow. The UNEP, the United Nations Environmenl Programs,and the World Meteorological Organization are establishing anintergovernmental panel to work on this.

I noticed Senator Baucus here who has been so active on this inthe Environment Committee and who spoke earlier. He and I haveworked together on this. I remember chairing the first hearings Ithink in June of 1986 on this matter.

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I want to congratulate you and urge you onward. With everybodypaying attention to this, I'm glad it's getting a high level of visibili-ty. Certainly it has a good turnout. I hope we can continue thisstruggle because it is up to us to do something. As was pointed outby Dr. Woodwell, the U.S. is the leader, and we have got to takethe lead on these matters.

Thank you, Mr. Chairman.[The prepared statement of Senator Chaffe follows:]

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STATEMENT O SENATOR' JOHN H. CHAFERBEFORE THE SENATE COMMITTEE ON ENERGY AND NATURAL RESOURCES

HEARING ON GLOBAL CLIMATE CHANGEJUNE 23t 1988

Mr. Chairman. You have selected one of the world's most

important and difficult environmental problems as the topic of

this hearing. I want to congratulate you for your efforts and

for your wisdom. What better time to hold a hearing on global

warming than during a 100 degree plus heat wave and a world-wide

drought?

Many jokes can be made about the timing of this hearing and

the current problems with excessive heat and lack of rain but

this is no laughing matter. So far, destruction of the earth's

climate system through the burning of fossil fuels and the

release of manufactured chemicals has been treated as a distant

threat or as a theoretical problem.

Finally, people are waking up to the fact that the problem

is real and, whether we like it or not# we are going to have to

deal with it. We are going to have to deal with it soon

We can look at Ocean City, Maryland and see that sea levels

are already rising. The drought typifies the kind of changes in

rain patterns that are predicted to occur as a result of the

greenhouse effect. The heat obviously gives us a preview of what

can be expected if we continue to stick our head in the sand and

deny that we have a problem.

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Mr. Chairman. Clearly, there are a great many questions

about the greenhouse effect that cannot be answered today. But

we should not let scientific uncertainty paralyze us. The issue

for us is "what steps should we be taking today to help solve

this problem in addition to more scientific research?"

On March 31 of this year, 41 Senators joined me in a letter

to President Reagan urging him to call upon all nations of the

world to begin the negotiation of a convention to protect our

global climate. That proposal is still under review and, in the

meantime, we are seeing progress at the international level.

At our urging, the problem of global climate change was

discussed by the world's leaders at the two Reagan-Gorbachev

summits, here in Washington and again in Moscow, as well as at

the economic summit recently held in Toronto. At the same time,

the United Nations Environment Program (UNEP) and the World

Meteorological Organization (WMO) are establishing an

intergovernmental panel to work on the matter.

We are making progress qut we have a long way to go and can

be doingta better job here at home. The way we waste energy in

this country is a crime. There are numerous things we can do

that would not only help solve the greenhouse problem but would

make economic sense as well. Improved energy conservation and

a requirement that autos run more efficiently would be two good

items to consider. i

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In the Environment Committee, I chaired a series of hearings

on this problem in June 1986. We have come a long way since then

and, with the help of you and your Committee# the press,

dedicated scientists, and a host of interested professionals# we

are managing to capture the attention of people all over the

world. That kind of grassroots support is critical if we are

going to succeed in our battle.

Mr. Chairman. Again, I commend you for your interest and

commitment to working on this matter and I look forward to

working with you as we go forward.

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Senator WIRTH. Thank you very much, Senator Chafee. You havecertainly been very active in the lead in so many aspects of thisissue.

Let me ask Senator Murkowski, who has joined us, if he has anykind of a statement or comments that he might like to make.

STATEMENT OF HON. FRANK H. MURKOWSKI, U.S. SENATORFROM ALASKA

Senator MURKOWSKI. Well, thank you very much, Mr. Chairman.First of all, I am fascinated, as we all are, by the significance of

the information. And I think particularly Dr. Woodwell's presenta-tion certainly stimulated my thought process to how we're going todo this, and his response to my question that by instituting CAFEstandards and insulation in homes and so forth could make a sub-stantial reduction in the hydrocarbons. But indeed, Doctor, whenyou were talking about a 50 or 60 percent reduction, it is inconceiv-able to me that you can achieve that kind of reduction from thoselimited capabilities in those narrow areas.

And I am just wondering if, indeed, we're not looking at somemore significant alternatives such as realistically increasing a de-pendence on nuclear power generation which is something that ourcountry has got a phobia over for reasons that we don't have to gointo. But considering and being practical, we only have so many al-ternatives. And I'm just wondering if realistically the scientificcommunity is prepared to address whether one of those alterna-tives has to be nuclear or whether we can achieve your percentagereduction some other way.

And I think there was a reference to my State of Alaska withregard to the question of the Arctic ecosystem changing. And I lookat these projections here, and it's really alarming. I noticed the redhas moved up to our area where it is still nice and cool. But thereis no question about it. Things are getting warmer. The winters arebecoming more mild.

So, my question is a general one. Is it, indeed, a reality that wemust look more aggressively to nuclear as a release because I don'tsee the public demanding any reduction in the power requirementsthat our air conditioners run off of, everything else that we enjoy.

Senator WIRTH. Senator Murkowski, if we might hold the specificquestions till we finish the three witnesses, if we might, because Iknow there are policy pieces that will be reflected in each of thestatements of the three people here.,

Senator MURKOWSKI. I'm going to have to excuse myself. So, Iwould appreciate it if one of my colleagues would be sure and seethat perhaps one of the witnesses could respond.

Senator FORD. You can depend on it.Senator WIRTH. Frank, this will be the first of a number of hear-

ings that we are going to be having on where we go from here. Andcertainly alternatives to fossil fuels are going to be one of themajor focuses of this committee's concerns.

We have three remaining members of the panel: Dr. SukiManabe, who has been with us before. We are really delighted tohave you back. Dr. Manabe, as I understand it, is going to focusparticularly on soil precipitation. We will then move to Dr. Dan

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Dudek from EDF who is going to talk particularly about the agri-cultural implications of the issues being discussed this afternoon.And finally, we will end up with Dr. William Moomaw who isgoing to bring us back to some broad policy concerns once more.

So, Suki, thank you very much for being here. And once more,we look forward to having your testimony.

STATEMENT OF DR. SYUKURO MANABE, GEOPHYSICAL FLUIDDYNAMICS LABORATORY, NATIONAL OCEANIC AND ATMOS-PHERIC ADMINISTRATIONDr. MANABE. Mr. Chairman and members of the committee, I ap-

preciate the opportunity to appear before you today. As I did beforethis committee last November, I would like to discuss the large-scale change in soil wetness. These changes which may have pro-found practical implications have received attention at various re-search institutions in North America and Europe. I shall begin mydiscussion by referring to the results obtained from the mathemati-cal model of climate developed at the Geophysical Fluid DynamicsLaboratory of NOAA.

Now, the first viewgraph shows the change in soil wetness in re-sponse the doubling of greenhouse gases in the atmosphere. Andthis is a model-produced result. This figure indicates that in thesummer soil dryness is reduced over very extensive mid-cost re-quired regions over the North the and Eurasian continents Theyellow indicates a region of a modest reduction, and the pink indi-cates a region where the reduction is relatively large.

In high latitudes, this midcontinental drying in summer ismainly due to the change in the seasonable variation of snow pat-terns. As you know, in winter, of course, snow prevails over themajor part of the high latitude part of the continent until it meltsin the spring. The snow reflects a large fraction of solar radiationsso that when snow disappears, a larger fraction of insulation is ab-sorbed by the ground which makes more energy available for evap-oration, so that when the snow melting season ends, then the rapiddrying of the soil begins from spring to summer.

Now, in the very warm climate spring to summer begins earlieras the snow melting season ends earlier. Therefore, the soil wet-nesm in summer is reduced. This is one of the important mecha-nisms in higher latitude drying.

In the middle latitude a similar mechanism involving snow coveroccurs particularly in high elevation regions. However, in middlelatitudes there is another factor which is more important. That is achange in the precipitation in the middle latitude rain belt. This isillustrated by a schematic diagram. That blue line in the diagramindicates how the middle latitude rain belt moves with respect toseason. In the abscissa you will see the different months of the

ar starting from January and ending December. And this rainIt is at the southern most latitude in winter. And as you go to-

wards summer, it moves northward although the summer rain beltbecomes a little more obscure by the convective rain which goesaround. And in Autumn it starts to shift southward again.

Now, in the C02 rich or greenhouse gas rich case, the atmos-phere is warmer and air can contain more moisture. So, the warm,

106

moisture-rich air can penetrate into higher latitudes, therebybringing more precipitation over there. Thus, in the northern halfof the rain belt, you get much more rainfall in the greenhouse gasrich case. In the southern half, it does not. And so what happens inthe warmer climate the ground surface is warmer and pollutionnot longer almost such everywhere. On the other hand, the precipi-tation increases much more in the northern half of the rain belt,but not in the southern half. Let's assume that you happen to livein a middle latitude location as season proceeds from January toApril, you gradually get into the southern half of the rain beltwhere it is drier. This is another mechanism which gives you driersummer soil in the mid-continental region in the middle latitudes.

As soil gets drier, the relative humidity and cloudiness in thelower atmosphere, thus very dry. Thus more sunshine hits theground. Therefore, there is more energy available for evaporation,and the soil gets even drier. Clouds are reduced further and soilbecomes. As the ground gets drier, and hotter, the lower atmos-phere becomes hotter, thus over continental sector jet stream tendsto move northward, thereby further reducing the precipitation inthe mid-continental regions. These are the mechanisms of mid-con-tinental summer drying as determined by a mathematical modelsof climate.

The summer reduction of soil wetness does not continue towinter. The model-produced discussed drought here is a rather sea-sonal phenomenon.

If you look at the next picture, the winter soil is mostly wetter inthe warmer climiate. The rain belt is located at the farthest southin the winter so that you are in the northern half of the rain beltwhere the increase of precipitation makes the soil wetter. Othermechanisms are also involved in a warmer climate a larger frac-tion of precipitation falls as rain. Futhermore, accumulated snowtends to melt easier in warmer climate, thereby making the soil inwinter wetter.

But one of the interesting things, which Jim Hansen mentionedearlier, is that soil wettness is reduced in the southwestern part ofthe United States in particular, in Southern California and itsneighborhood where-you get most of rainfall in winter. As I notedearlier, the winter rain belt is located at the southern most lati-tude in winter. So, southern California is at the southern fringe ofthis rain belt where it has become drier in a warm climate so thatyou can see dry regions up here in the southwestern part of NorthAmerica in winter. This is a result which appears in most of themodeling experiments, not only in our own, but also in many otherresults.

In short, these soil moisture changes substantially in the verycrucial region of the United States. I have to emphasize, however,that modeling results about the soil wetness change are less robustthan the temperature change which Jim Hansen discussed ex-plained. It's important to note that the results obtained by variousmodeling groups are not in complete agreement though morerecent results indicate mid-continental summer dryness. In myopinion, some uncertainty in the estimate of future hydologicchanges stems from summer dryness.

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And I think this is due to our inability to make sufficient by re-alistic models which correctly incorporate, the various physicalprocesses, in particular, the treatment of the land surface processis highly rudimentary at the present time. For example, the proc-esses of the biosphere-climate interclim that Dr. Woodwell thinksare very important are not included in the model. So, it is veryurgent to improve the climate models in order to gain more confi-dence in our predictims.

These results clearly indicate that summer reduction of mid-con-tinental soil moisture results from global warming and is a verylarge scale phenomenon. The physical processes responsible for thisenhanced dryness appear reasonable. In summary it is likely thatsevere mid-continental summer dryness will occur more frequentlywith increasing atmospheric temperatures as warming becomeslarger and larger toward the next century.

One is tempted to ask whether the current dry condition in theUnited States results from the general warming trend in the north-ern hemisphere which Dr. Hansen mentioned earlier.

Unfortunately, I have not analyzed the current drought enoughin sufficient detail to discuss this topic with confidence. However,since the past increase of global mean surface temperature duringthis century is only several tenths of a degree so far, natural varia-bility of surface conditions can easily overshadow any surface re-duction of soil moisture induced by this much warming. So, it ismore likely that the current drought is a manifestation of the nat-ural fluctuation of soil dryness rather than greenhouse-induced.However, I suspect that the process of dryness which I identified byour numerical experiment may be involved in aggravating currentdry conditions. And I feel that this current drought provides an ex-cellent example of the kind of drought which occurs more frequent-ly as the global warming becomes larger.

In concluding my testimony, I believe it is essential that in-creased research efforts be devoted to improving the basic compo-nent of climate models in order to improve the reliability of ourpredictions. One -common shortcoming of the current models is thecoarseness of their computational resolution. This not only distortsthe dynamics of a model atmosphere, but also prevents us frompredicting geographical details of future climate change. When youtry to ask what is a climate change in a State, e.g.) Colorado, weare helpless. The additional computer resources, including the su-percomputer, are desired for this purpose.

Obviously, prediction of future climate change should be continu-ously verified and updated through continuous monitoring of theclimate and the factors inducing climate change. In order to dothis, a major commitment of resources are needed for satellite andin-site observation of our environment.

Mr. Chairman, this completes my present statement.[The prepared statement of Dr. Manabe follows:]

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TAU OF

GUOPUYIICLL FLUID DYNAICS LABORTORYNATIONAL OCEANIC AND MIIOSPIC ADMINISTRATION

U.S. DEPARSIUF OF VuUV

(OUITTIE ON RNEWY AND NATURAL BUNID ETMES SUATE

JUNE 23v 1988

Mr. Chairman and Members of the Committee:

I appreciate the opportunity to appear before you today to

comment on climate changes due to the future increase of

greenhouse gases. As I did before this Committee last November,

I would like to discuss the large-scale changes in soil wetness.

These changes, which may have profound practical implications,

have received increased attention at various research

institutions in North America and Europe. I shall begin my

discussion by referring to the recent results (1,2) obtained from

the mathematical models of climate developed at NOAA*s

Geophysical Fluid Dynamics Laboratory.

The mathematical model of climate used for this study is a

three-dimensional model of the atmosphere coupled with models of

the land surface and a simple mixed layer ocean. It includes the

effects of solar and terrestrial radiation and the hydrologic

cycle and explicitly calculates the general circulation in the

atmosphere using the hydrodynamical equations. It has been shown

109

that this type of climate model successfully simulates the

seasonal and geographical distribution of climate-parameter. The

impact of increased greenhouse gases on climate was evaluated by

comparing climates of the model which have the normal and above-

normal concentrations of atmospheric carbon dioxide. -

A map of the C02 -inducod change of soil moisture for the

June-July-August period is illustrated in Fig. la. This figure

indicates that in summer, soil becomes drier over very extensive,

mid-contirnemtearegi of North America, Southern Zurope and

dioxide. In some regions, the reduction amounts to a substantial

fraction of the soil moisture present in the normal-CO2 c

Over Siberia and Canada, changes in snow cover are

responsible for the C02-induced reduction in soil moisture. In

these regions extensive snow cover prevails during winter before

molting in the late spring. Since snow cover reflects a large

fraction of incoming sunshine, its disappearance increases the

absorption of solar energy by the land surface to be used as the

latent heat for evaporation. Thus the end of the spring snowaelt

season marks the beginning of the seasonal drying of the soil

snowmelt season ends earlier, bringing an earlier start of the

spring to summer reduction of soil moisture. An a result, the

soil becomes drier in summer.

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Over the Great Plains of North America the earlier anowuelt

season also contributes to the C02-induced reduction of soil

wetness in simmer. In addition, changes in the mid-latitude

precipitation pattern also contribute to the reduction of soil

wetness in smmer over North America and Southern Europa. Both

of these regions are under the influence of a rainbelt associated

with the typical path taken by id-latitude low pressure systems.

in the high CO2 atmosphere, warm moisture-rich air penetrates

further north than in the normal-CO2 atmosphere. Thus the

precipitation rate increases significantly in the northern half

of the aid-latitude rainbelt whereas it decreases in the southern

half. Since the rainbelt moves northward from winter to summer,

a mid-latitude location lies in the northern half of the rainbelt

in winter and in its southern half in sumner. At such a location

the C0 2 -induced change in precipitation rate become negative in

early summer, contributing to a reduction of soil moisture. The

summer dryness is enhanced further due to the increased sunshine

reaching the ground as reduced evaporation from the drier

continental surface causes a decrease in cloudiness.

The sumr reduction of soil wetness discussed above does

not continue through winter. In response to the increase of

atmospheric carbon dioxide, soil wetness increases in winter over

extensive id-continental regions of middle and high latitudes

(as indicated in Fig. lb). In middle latitudes, this is mainly

due to the increase of precipitation in the northern half of the

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middle latitude rainbelt. In high latitudes, a larger fraction

of precipitation is realized as rainfall, making soil wetter.

Fig. lb also indicates that soil wetness is reduced in winter

around Southern California and Mexico. The reduced rainfall in

the southern half of the middle latitude rainbelt is again

responsible for this enhanced dryness.

Upon inspecting Fig. 1, one should keep in mind that only

these very broad scale features of the soil moisture changes are

significant. For example, many of the small scale features in

the tropics and Southern Hemisphere are not regarded with much-

confidence. This is partly because the climate modole used in

this study have coarse computational resolution and fail to

simulate the small scale features of the hydrologic change.

Furthermore, the detailed features of the C02-induced change are

often obscured by large natural fluctuations of soil wetness,

thereby making the identification of these features very

difficult.

One should also note that the various research groups have

not reached unanimous agreement (3,4) on the issue of the aid-

continental summer dryness. Results from more recent studies

(5,6) appear to agree better with those presented here (7,8). In

my opinion, some uncertainty in the estimate of the future

hydrologic change stems from the difficulty of reliably

incorporating into a climate model various relevant physical

112

processes, such as the land surface water budget and ocean-

atmosphore interaction. Nevertheless, the above discussion

clearly indicates that the summer reduction of aid-continental

moil moisture results from the global warning and is a very large

scale phenenon. The physical process responsible for this

enhanced dryness appears reasonable. In summary, it is likely

that severe nid-continental summer dryness vii occur more

fr euently with increasing atmospheric temperature.

One is tempted to ask whether the current dry condition in

the United States results from the general warning trend in the

Northern Hemisphere. Since the past increase of global mean

surface air temperature during this century is about several

tenths of a degree Celsius, natural variability of surface

conditions can easily overshadow any summer reduction of soil

moisture induced by the warning. Nevertheless, it is likely that

the processes identified by our numerical experiments are

involved in aggravating the current dry condition.

In concluding my testimony, I believe it is essential that

increased research effort be devoted to improving the basic

components of climate models in order to improve the reliability

of our predictions. One common shortcoming of the current models

is the coarsenss of their computational resolution. This not

only distorts the dynamics of a model atmosphere, but also

prevents us from predicting the geographical details of future

113

climate change. improved computer support is required for better

computational resolution.

Obviously the prediction of future climate change should be

continuously verified and updated through continuous monitoring

of the climate and the factors inducing climate change. In order

to do this, increased observations of our environment are

required.

Kr. Chairman, this completes my prepared statement. I would

be glad to answer any questions you night have.

114

1Jun.-Jul.-Aug.

00 .i X

30 60 90 120 ISO 180 150 120 90 60 30

Dec.-Jon.-Feb.

30 60 90 120 ISO 1S0 150 120 90 60 30

Fig. I The geographical distribution of the difference in soil moisture (cm)between the high C0 - and the normal C02-experiments. See (2) forfurther details. (a) June-July-August period. (b) December-January-February period.

115

1. Manab., S., and R.T. Wetherald, 1986. Reduction in srmer

soil wetness induced by an increase in atmospheric carbon

dioxide. 9c2anL.,3.L, 626-632 (2 May 1966).

2. anable, 8., and R.T. Wetherald, 1967. Large-scale changes

in soil wetness induced by an increase in atmospheric carbon

dioxide. J. of &tros. Sa. - A, 1211-1235.

3. Schlesinger, M.3.1 and J.7.B. Mitchell, 1985. Model

projection of equilibrium climate response to increased CO2.

In MacCracken, N.C. and Luther F.M. (eds.): Projecting the

Climate Effects of Increasing Carbon Dioxide, DO/ZR-0237.

U.S. Department of Inergy, Wash., D.C. pp. 81-147.

4. MacCracken, M.C., X.Z. Schlesinger, M.R. Riches, and S.

Manabe, 1986. Atmospheric Carbon Dioxide and Summer Soil

Wetness. A letter and a response. iAne, 2a, 659-660

(7 Nov. 1986).

5. Mitchell, J.F.B., 1986. ZM iamal Climatoloy. Tech. Note

39, Meterological Office, Bracknell, Berkshire, England.

116

6. sohleaeinqsr, K.3., and 3.o. Shao, 1964 SOsOnal CL]mate.

Changes induced by doubled 02 as siouLated by the 080

atmospheric 01/mixed layer ocean model. J...imamt 1, in

press.

7. Kellog, W.V. and 3.0. Zhao, 1968: Sonsitivity of soil

moisture to doubling of carbon/dioxide in climate model

experiments. Part 1: North America. J.CI)XA~., 1 , 346-

366.

8. Shao, Z.c. and W.W. Kellog, 1986. Sensitivity of soil

moisture to doubling of carbon dioxide in climate model

experiments. Part 11: The Asian monsoon region.

JL. CJitn, .1, 367-378.

117

Senator WIRTH. Thank you very much, Dr. Manabe.Dr. Dan Dudek from the Environmental Defense Fund will focus

in particular on the agricultural implications of global warming.Dr. Dudek, thank you for being here.

STATEMENT OF DR. DANIEL J. DUDEK, SENIOR ECONOMIST,ENVIRONMENTAL DEFENSE FUND

Dr. DUDEK. Thank you for inviting me, Mr. Chairman. My nameis Dan Dudek. I'm a senior economist with the Environmental De-fense Fund, but more importantly, I'm an agricultural economistboth by training and avocation.

I don't think we need to be reminded by current headlines of theincredible sensitivity of agriculture to weather. It is the mostweather-sensitive sector of our economy. At the same time, I'm nothere to tell you that current drought conditions are, in fact, evi-dence of a global climate change. Rather, I think that the droughtthat we are currently suffering is an opportunity to help us con-ceive of what a greenhouse world would look like.

What I will present today in my testimony are results from anal-yses that we have conducted at EDF concerning what agriculturemight look like under a changed climate. I would emphasize thatthese changed climatic conditions are normal conditions under achanged climate and not abnormal drought conditions as we areexperiencing them now.

If I could have the first slide please. What we have done is tointegrate both changes in atmosphere as manifested in terms oftemperature and changes in evapotranspiration, water demand byplants with agronomic models which describe the relationship ofcrop productivity to temperature increases. Crop productivity ismeasured on the vertical access; temperature on the horizontal. Asyou can see, this is clearly a case where more is not better. In fact,for corn we have estimated for one particular climate scenario,that of the scenario A, corn yield reductions ranging between 22and 27 percent depending upon both location and the treatment ofcarbon dioxide effects.

Other than temperature, there will be a whole host of additionalstresses on crops in agriculture. These include traditional environ-mental pollutants, ozone and perhaps also increases in ultravioletlight associated with stratospheric ozone depletion. The soil mois-ture changes described by Dr. Manabe are important. These arenot included in the model. Increases in concentration in carbon di-oxide have a positive effect.

So, the results I will present today emphasize three different as-pects of the problem. First is the carbon dioxide effect; second, thatassociate with climate change impacts; and third, the combinationof these two. I will emphasize the latter two-that is, the climatechange effects and the combination of the two-as being the mostlikely outcome.

if I could have the second slide please. In our work we integratedthe biologic changes with an economic model, one developed by theU.S. Department of Agriculture and adapted for this purpose. It isa national model. And these results show aggregate production

118

changes for the U.S. economy under a changed climate, in this caseone associated with a doubling of the CO concentration.

If we look at the two sets of bars-that is, those in the middleand those on the far right, one for climate change and one for com-bined-let's, for example, look at the yellow bar. That is that asso-ciated with corn. Current estimates are that the corn crop rightnow is suffering about an 11 percent decline in production. We areentering a critical period for corn in the next 10 days. We know thenumber of days above 95 degrees, as well as the amount of mois-ture available for corn, is a critical determinant of its yield. Therange of yield reductions for corn predicted from our analysis are 9to 14 percent.

For wheat, oats and barley, two other crops which have beenmentioned as being significantly stressed currently in the droughtsituation in the middle west and great plains, we have predictionsof changes in yield ranging between I and 20 percent. CurrentUSDA estimates are for 22 percent national reduction in the pro-duction of those three commodities. So, again, we are in roughly asimilar range of agreement.

If we step back and take a look at this question from an aggre-gate standpoint and ask what are the impacts in terms of theottom line, dollars, the range of impacts here for both the com-bined and the net effects run between $1 billion and $12 billion onan average annual basis. Now, how can we stack that up againstcurrent conditions. Currently we are estimating that drought losseswill run, as of right now, about $3 billion.

We can also get a rough magnitude of the size of these damagesby comparing them with other environmental stresses on agricul-ture. It has been estimated that damages due to tropospheric ozoneor smog are about $2 billion annually. Those associated with ultra-violet light and its increase from stratospheric ozone depletion areabout $2 billion and a half annually. So, this is a very severe anddrastic change indeed. I would emphasize that these are undernormal conditions of a future climate.

Associated with the production declines, we would expect priceincreases reflecting reduced availability and scarcity of crops. Wecan also compare the predictions from these modeling studies withcurrent events right now. For example, the purple bars show theresponse for soybeans, showing roughly about a 75 percent increasein price under the climate change only scenario. That compareswith the jump in July soybean prices on the future markets ofabout 100 percent currently. If we look at July corn in the futuresmarket, that's about a 72 percent increase. We're showing some-thing around the order of a 65 percent increase, et cetera. We cancontinue to make these comparisons.

The point is here, first, that we have seen a rekindled interest infear of inflation in the markets overall and a weakening of confi-dence in financial markets as a result.

The third slide please. One of the responses that we would expetto occur for climate change is a shifting cropping pattern, shiftilocation of crops in responding to the differential environmentalstresses of climate change, as well as the availability of water re-sources. On this slide the yellow and red bars similarly show forclimate change and for the net effect increases in dry land crop

119

acreage that would be stimulated in the northwestern part of theUnited States associated with climate change. That is, one of thecompensations for the yield reductions is to increase the intensityof agricultural development. In fact, one of the problems associatedwith such shifts and such increased acreage is whether resources,like soil moisture, as Dr. Manabe indicated, will be adequate tosupport that. Those changes have not been included in this analy-sis.

The next slide please. One of the other results that we observe isa shift in cropping methods-that is, from dry land systems to irri-gated agriculture. This slide shows the associated changes in irriga-tion water demand. As you can see, in the northern tier states inparticular increases of roughly 40 percent or more in terms of irri-gation water demand are forecast.

The question again is whether supplies will be available. As wehave precipitation changes, we will change the mix between rainand snowfall. In one study that has been done in California, for ex-ample, the result is an earlier spring snow melt. There is a greaterrunoff, but that runoff is not able to be captured by the existingdams. They were sized for normal historic climates and not forchanged climates. In order to maintain their flood control capabili-ties, those releases have to be increased. The result is a reductionin the free water storage provided by the snowpack and a reductionin the deliveries of irrigation water supplies to state water projectareas in particular in California. On an average annual basis, theserun up to 30 percent; under adverse conditions, they could be ashigh as 50 percent.

A conservative estimate of the value of investments in Californiawater supply works is roughly $15 billion to $20 billion. A questionhere is since water supply investments have been politically con-tentious-one recent example is the Two Forks Dam proposed inColorado, one that has been called the dinosaur-we might ask le-gitimately whether, in fact, climate change will resurrect the dino-saurs.

In conclusion, the results that we are demonstrating here todayare, in fact, robust across a wide range of model studies, some ofwhich are being conducted by the Environmental ProtectionAgency now under the auspices of the Global Climate Protection A

Act. They lead to several recommendations.First, perhaps what is most appropriate is the current advice

being pandered on Wall Street; that is, we ought to diversify ourportfolio. We ought to hedge against these kinds of risks. By that Imean we ought to expand the range of choices that we have avail-able to us.

If we look to the success of achieving cooperative internationalagreement to manage the problem of stratospheric ozone depletion,in part that was facilitated by the existence of alternative chemi-cals that we could turn to. Those alternatives lessened the sharp-ness of the tradeoff between economic wellbeing and environmen-tal quality. It is important that we develop those options nowbefore crisis situations are upon us.

Next, productivity research and development is very important.One way to think about the kinds of productivity impacts in agri-culture that we have been showing is to think about what kinds of

1 120

increase in productivity would be required to compensate. Over thepast several decades, we have averaged about a 1 and three-quarterpercent per year increase in agricultural productivity. For somecrops, it would take nearly two decades of thatkind of sustainedeffort just to stay even with the kinds of yield reductions that wehave been showing.

Efficiency has been mentioned both with respect to energy, inparticular end use, and in generating energy. One of the importantcompensations that we predict is an expansion of groundwater use.Groundwater use is critically dependent upon energy pricing. It de-termines its feasibility and thus the ability of the use of that re-source to compensate for these kinds of agricultural stresses.

Water efficiency is also important. And in that regard, one of thevery important things that we can do is to give citizens in generalthe correct signals, give them the right incentives. This is true forboth energy and for water. In the water area, we can develop watermarkets which would both facilitate the flexible movement ofwater in response to changes in crop location, as well as to give ex-isting water users reasons to conserve water.

In particular in the energy arena, including environmental ef-fects or environmental costs in energy investment decision makingwould be an important contribution to assuring that we make thecorrect choices about our energy future.

I thank you for the opportunity to address the committee today.[The prepared statement of Dr. Dudek follows:]

121

ENVIRONMENTAL DEFENSE FUND1616 P Street, NWWashington, DC 20036(202) 387-3500

STATEMENT OF DR. DANIEL J. DUDEKSENIOR ECONOMIST, ENVIRONMNTAL DEFENSE FUND

BEFORE THE

SENATE COMMITTEE ON ENERGY AND NATURAL RESOURCES

concerning

GLOBAL CLIMATE CHANGE

UNational Headquarters257 Park Avenue SouthNew York, NY 10010(212) 505-21001405 Arapahoe AvenueBoulder, CO 80302(303) 440-49015655 College AvenueOakland, CA 94618(415) 658-8006

1106 Eaue Main StrektRichmond, VA 23219(8O4) 780-1297128 East Harget StreetR~, NC 27601(919) 821-7793

June 23, 1988

-em-b how

122

Mr. Chairman and members of the comittee, thank you for the

opportunity to testify at this hearing concerning global climate change. The

committee's interest in this problem at this time is a strong signal of the

active concern and priority attached to this problem. One of the difficulties

involved is conceiving the problem. We are fortunate that the science allows

us to simulate, however uncertainly, possible alternative futures with

computer models. As vivid as their pictures of the future might be, they fail

to capture those changes in a human day-to-day context. The daily headlines

concerning the high temperatures and drought currently scourging the aid

western part of the nation help to complete the picture.

The buffeting that agricultural communities are suffering is a tangible

reminder of our vulnerability to weather and the stakes involved in the

threat of global climate change. My testimony today centers on a study

undertaken by the Environmental Defense Fund, a copy of which will be

submitted for the record, to describe the Implications of climate change for

U.S. agriculture and its customers. While the study examines only one

possible future climate outcome representing normal weather, the results have

broad similarity to current conditions. Crop prices would rise, production

would fall, and competition for water would increase dramatically. Domestic

consumers would pay higher prices and foreign importers would be fortunate to

receive any crop.

As stewards of the future and managers of today's resources, we should

ensure that the nation possesses a diversified portfolio of strategies to

respond to these threats. Agreement in Montreal on protecting the ozone layer

was possible because feasible, practical alternatives existed. We need

investments and institutional changes that will broaden our alternatives,

I

123

lessen the burden of response, and hedge against catastrophic surprise.

Continuing with business as usual is a huge gamble that market forces or

future policy-makers will have enough vision, time, or resources to produce

cost-effective alternatives for responding to climate change.

ASSESSING THE IMPLICATIONS OF CLIMATE CHANCE FOR AGRICULTURE

GelS Agra

The basic approach in our study was to integrate basic physical,

biological, and economic processes. Predictions of important climatic

factors like temperature, precipitation, and evaporation are taken from

general circulation models (GCOs) such as those developed at NASA's Goddard

Institute of Space Studies (GISS) and the General Fluid Dynamics Laboratory

(GFDL). Results from the 7ISS 0C0 were used in this study (Hansen, et

AL, 1986). Crop growth depends critically upon both the magnitude and

timing of changes in these climatic factors. Agronomists have long studied

these interrelationships and developed models to predict crop yields in

response to changes in climate. The predictions from the GCOs can be

combined with those agronomic models to produce estimates of yield changes

under different future climate regimes.

Host previous studies of the impact of climate change on agriculture

have stopped there. However, several key ingredients are missing. As most

of us know, farmers are astute entrepreneurs. They are not likely to be

passive in the face of such change, but rather will adjust and respond to

market forces. Crop locations will shift and production techniques will be

altered in response to market outcomes driven by the produc.tivLty changes.

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124

In order to capture these econmie responses, we haM adapted s national

mode of agriculture originally developed by the Economic Research Service

of the U.S. Department of Agriculture (Homer, al L, 1985). Coupling

this economic model with crop productivity changes allows us to estimate

both the role of market forces and the resulting geographic cropping

patterns.

Although only one climate scenario from one OCK was analyzed (the GISS

scenario A), different assumptions concerning the crop productivity effects of

those climate changes were estimated. Crop yields will be affected by 4 main

factors: temperature, CO concentration, evapotranspiration, and

precipitation. While minimum temperatures are necessary for crop growth (see

Figure 1), temperature increases will be the main source of yield reductions.

Soil moisture changes from altered precipitation patterns and temperature

increases will also be an important determinant of yields. CO2

concentration increases will have an inadvertent fertilization effect and tendto increase yield. However, crops vary In their ability to use the increased

CO,. Corn and sorghum, for example, would benefit less than other crops.

Thus, the relative impacts of both climate and atmospheric changes will vary

by crop. Agronomists are currently working to integrate both effects in their

models of crop growth. Crop productivity impacts for this study were taken

from a range of estimates in the published literature and are cited in the

report submitted for the record. The study reported here today analyzes CO2

and climate change effects separately and then combined.

Fvure 1. Producton Rates for Crop Groups byTemperature

5 10 15 20 29 so

Surface Air Temperature (degrees Celsius)

Source: Doorenbos and Kassam (1979), p. 12

0-

0

4-0

4-

C-)

-o-0

00

0

0

'UM

40

10

0

126

SUOIARY OF RESULTS

The yield reductions evaluated in this study varied anon& crops and

scenarios. For example, in the corn bolt, corn yield reduction were

estimated to range from 22-270 depending upon whether CO. effects are

included or not. Experts in that region have been recently quoted as

predicting a drop of 1II in national average corn yields currently

(KaLdenberg, 1988). Other crops currently affected by drought, wheat, oats,

and barley, are also expected to suffer yield reductionslrangLng from 1-25*

depending upon location and CO. effect. Soybean yields are estimated to

span a range between 0.5-27t lower.

In the aggregate, these yield changes were estimated to cause a loss in

economic welfare from agriculture of between $0.6-$11.6 billion in 1982

dollars in average annual terms. In contrast, current estimates of the

effects of the drought are approximately $3 billion for three major crops

(Associated Press, 1988). The estimates of damage to agriculture from ther

environmental problems are also useful comparisons. Tropospheric ozone or

smog is estimated to cost the agricultural economy approximately $2 billion

annually (Adams and KcCarl, 1985. Stratospheric ozone depletion and the

increased ultraviolet radiation that it would generate would cost about $2.5

billion (Adams and Crocker, 1987). The climate change Impacts upon

agriculture can be several times larger than the damages caused by these

environmental stresses.

While the economic welfare effects may be substantial, Americans are not

expected to have difficulty feeding themselves. Foreign consumers will face

5

127

the bulk of the supply reductions as exports contract due to reduced supplies.

Figure 2 displays the aggregate national production changes estimated under

the alternative scenarios. Wheat, barley, and oat production is currently

expected to be reduced by 221 as a result of the drought (Schneider, 1988).

Under climate changes, barley production is estimated to decline between

1-19.50, while wheat would be off 1.5-7%, and oats from 1-14%. It is

important to remember that the results of this analysis also allow for

long-run shifts In the location of crop production in response to changes in

competitive advantage, whereas the drought impacts are shocks to crops and

Investments in place and so reflect short-run impacts.

The severity of the currentI drought for the corn crop will be determLned

in the next 10 days as we enter a critical phase of crop development. The

number of days above 950 F have been shown to be a critical determinant of

corn yields (Nearns, &L Aj, 1984). Corn is expected to be severely

affected by climate change due to its relatively poor utilization of CO.

increases. As shown in Figure 3, corn production could decline between 9-14%.

Production declines will be met by price rises, a phenomena we are

witnessing now in agriculture duo to the drought. Soybeans have hit their

highest price In 11 years. On the futures market July soybeans have jumped

nearly 100% this year. July corn is up 720 and September wheat has risen

55%. The price changes predicted In this study under some scenarios are

roughly the sane magnitude (see Figure 3). Much of the concern about these

price hikes focuses on their impact in rekindling inflation and weakening

the confidence of financial markets.

6

Figure 2. Aggregate Crop Production Changes

Percentage Change from 1982 Base

1 Barley

Corn

SCotton

SOats

Rice

mSorghumSSoybeans

SWheat

2 x C02 Climate Change Combined

20

15

10

5

0

-5

-10

-15

-20

Figure 3. Aggregate Crop Price Changes

Percentage Change from 1982 Base

250

200

150

100

50

0

-50

-1002 x C02 Climate Change Combined

E-Barley

Corn

Cotton

Oats

Rice

Sorghum

Soybeans

Wheat

130I

REGIONAL CHANGES IN CROPPING PATTERNS AND RESOURCE USE

The results previously described are generally robust in the direction of

changes that they describe. Similar studies being prepared under the Global

Climate Protection Act, In their preliminary form, describe the same patterns

across a wider of GQas, scenarios, and more detailed crop productivity

assessments. One of the more notable general results is a geographic shifting

of agriculture and a shift to irrigation. Figures 4-8 decribe these acreage

changes. Note that in Figures 4 and 6, substantial increases in dryland

acreage are estimated. These are exactly the regions that are being hit

hardest by the drought. As indicated in the limitations section of this

testimony, precipitation and soil moisture impacts of the sort described by

Nanbe and Wotherald (1986) were not included in this analysis. In those that

have included these changes, the shifts described here are intensified and

the losses greater.

One of the important shifts that night occur under these conditions is an

intensification of irrigation throughout the nation, but particularly in the

northwest and northern Great Plains (see Figure 8). While increased

Irrigation particularly from groundwater has been a historic response to

drought conditions, it is uncertain whether groundwater resources in the

future will be economically available. Current incentives t4 farmers

encourage groundwater mining in excess of recharge rates. Future physical

supplies of the resource into the future are uncertain on this basis alone.

Further, the impact of changes in precipitation and runoff in a greenhouse

world have not been determined for groundwater. Energy prices are also an

important determinant of the economic feasibility of groundwater pumping and

Figure 4. Eastern Dryland Crop Acreage Changes

9.

0-6

LEGENDS Chane from I9

lmmL ct

Figure 5. Southwestern Dryland Crop Acreage Changes

I.'

co

Scenmis

Figure 6. Northwestern Dryland Crop Acreage Changes

LEGENDs ChV from 1982

igure 7. Southwestern Irrigated Crop Acreage Changes -

Figure 8. Northwestern Irrigated Crop Acreage Changes

C0Ovl

LEGENDS Chang* from 1982

Chongi~ombl nd

Scenarios

136

present another critical element of uncertainty which could limit the

effectiveness of irrigation in mitigating climate change impacts.

WATER SUPPLY AND INVESTMENT

The shifts to groundwater are illustrated in Figure 9 which displays the

results of a similar analysis focused on the state of California alone.

The Central Valley regions (Sacramento, Northern andd Southern San Joaquin)

show marked changes in groundwater use. In part, these are driven by changes

in surface water supplies. Although runoff is expected to be increased, it

cannot be captured by existing facilities built upon assumptions of an

unchanged climate. The result is average annual reductions in state

water project deliveries of 25-280. At an average cost of $500 per acre-foot,

a rough approximation of the value of the investment in California water

projects alone is $15-20 billion. An important question underlying the

geographic adjustments previously described is whether new Investments of this

magnitude are possible given the controversial nature of dams.

Public strife over water is not now, but climate change could raise it

to a new level. The controversy surrounding the proposed Two Forks Dam in

Colorado is an good case in point. Opponents have called the project a

"dinosaur*. Giben the predicted impacts of the greenhouse effect, we might

well ask whether climate change will resurrect the dinosaurs.

The critical importance of water to agriculture is also demonstrated by

the transportation bottleneck caused by low Mississippi River flows. While

agricultural development in adjustment to climate change may not be limited

by land, infrastructure such as transport and water supply may be lacking

137

-igure 9. Regna Resource Changes

"Wo- --m"

16

I

I

138

and limit such adjustments.

LIMITATIONS

The results presented in this testimony are computer experiments

designed to describe the current agricultural economy if it were subjected

to the types of climate changes predicted from the GCQs. No attempt has

been made to forecast agricultural technologies of the future. The tastes

and preferences of consumers are those expressed today. Exports are

maintained at present levels despite the fact that climate change is a

global phenomenon which affect agricultural regions around the world and

thus the international markets for commodities.

Resources essential for agricultural production such as water and land

will also be affected by climate change. For example, warmer temperatures

will alter the mix of precipitation between snow and rain as well as

shifting the timing of the spring melt. In western regions dependent upon

irrigation, the loss of reservoir storage provided by the snowpack can mean

reduced water supplies. Even if stream flow is increased in some locations,

existing reservoirs have been sized to match the size and timing of historic

flows. Increased early season runoff would force water supply operators to

increase releases downstream in order to maintain the flood control

capabiliites of their facilities. Changes in precipitation and runoff

patterns will also affect groundwater recharge and availability. None of

these water supply impacts have been included in this study, although

estimates of changes in groundwater pumping are made. Similarly, land

resources are presumed to be available for agricultural production.

17

* 139

CHAUMGS AND IMPLICATIONS

Technical 2AM MA jnd Ith morance 9f RD InlestMflo

Another useful way to think of the implications of the agricultural

changes that could occur is to relate them to the changes in productiviy that

we have observed in the past. Over the past several decades agricultural

productivity in the form of increased yields has averaged about 1 3/4% per

year. For some crops under some of the scenarios, sustaining this rate for

more than a decade would be required to roughly balance the negative

productivity impacts.

The importance of research and development investments was one of the

critical lessons from stratospheric ozone protection efforts. The scope

of feasible policy actions had been significantly expanded by private

investments in the 70's to investigate alternative chemical formulations.

The existence of these alternatives reduced the threat of radical lifestyle

changes and eased the way for international agreement.

The limited responses available to policy makers concerned with the

drought demonstrate the importance of developing choices well before they are

needed. In addition, including climate change among the reasons for action on

other environmental problems is only prudent. Given the importance of market

signals to all actors in the economy, distortions in those incentives whether

due to market failure or government intervention should be removed if we

expect private citizens to make informed decisions. For example, linking

income transfers to agriculture to production maintains more resources in

18

140

agriculture and increases the stakes in the climate gamble. Efficiency in

vater can be encouraged by promoting the development of vater markets. Such

markets vould improve present efficiencies, reduce pollutant loadings, and

facilitate resource transfers in response to climatic change. The failure to

include environmental effects as a factor in public utility investment

decisions concerning energy production also increases our risks. End

use and generating efficiencies would be improved by this change. There

are many good reasons to hedge our bets, not the least of which is the damage

mounting up in the Middle West.

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141

REFWRECES

Adams, Richard M. and Thoms D. Crocker, "The Impact of Pollution from OtherSources on Agriculture: An Assessment and Review of the Economicsu, paperpresented for the OECD workshop on the Integration of Environmental Policieswith Agricultural Policies, Paris, France, Nay 11-13, 1987, 47 pp.

Adans, Richard N. and Bruce A. NcCarl, "Assessing the Benefits of AlternativeOzone Standards in Agriculture: The Role of Response Information", Journal ofEnvironmental Economics and management, vol. 12, 1985, pp. 264-76.

Associated Press, "Middle West Showers Tease But Are 'Too Little, Too Late',feiXnok Ties, June 17, 1988, p. A15.

Hansen, J., A. Lacis, D. Rind, G. Russell, P. Stone, I. Fung, P.Ashcraft, S. Lebedaff, R. Ruedy, and P. Stone, "The Greenhouse Effect:Projections of Global Climate Change', J.G. Titus (editor), Effects ofChange na Stratogbric Ozone AW Global Cutejg , vol 1: Overview, pp.199-218, October 1986.

Homer, Gerald L., Daniel Putler, and Susan E. Garifo, "The Role ofIrrigated Agriculture in a Changing Export Market", ERS Staff ReportAGES850328, Economic Research Service, USDA, 31 pp.

Manabe, S. and R.T. Wetherald, "Reduction in Summer Soil Wetness Induced by anIncrease in Atmospheric Carbon Dioxide*, Science. 232:626-28, 1986.

Nearns, Linda, jM* gl., "Extreme High Temperature EvenLs: Changes in TheirProbabilities with Changes in Mean Temperature*, Journal of Climate andAolied HtoU g, vol 23, pp 1601-13, 1984.

Naidenberg, H.J., "Soybeans and Corn Rise Again", ew York Times, June 18,1988, p. 33.

Schneider, Keith, "Half of Wheat, Barley and Oats In Northern Plains Lost toDrought', &e Xork TLmes. June 22, 1988, p. 1.

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Senator WiRTH. Thank you, Dr. Dudek.Finally, Dr. William Moomaw. Bill, thank you for being with us.

STATEMENT OF DR. WILLIAM P. MOOMAW, DIRECTOR, CLIMATE,ENERGY, AND POLUTION PROGRAM, WORLD RESOURCES IN.STITUTEDr. Moomw. Senator Wirth, I want to thank you for the oppor-

tunity to testify at this hearing.The testimony by those who have preceded me represents a truly

remarkable consensus. The evidence is quite conclusive that carbondioxide and other greenhouse gases are increasing as the result ofhuman activity. The majority of this increase, it is agreed, is relat-ed to fossil fuel combustion, and additional amounts of warmingmay be occurring as a result of the release of chlorofluorocarbonsfrom deforestation and from agricultural practices.

The data presented by Dr. Hansen convincingly demonstratesthat the global average temperature is, indeed, rising by anamount that exceeds expected fluctuations from the climatic mean.'The implication of this analysis is that the global climate is warm-ing. For some who may not be as familiar with statistical analysis,the question remains how confident can we be that this is reallythe case.

As a physical chemist who has carried out basic research in thelaboratory over the last 24 years where I can control all the varia-bles, I expect to get data that is good to the 95 to 99 percent confi-dence level. From the work I have done over the last half a dozenyears on acid rain out in the field, I feel fortunate when I see acorrelation that is in the range of 60 percent of probability thatthat is not a chance event. So, for his analysis to show a deviationwith 99 percent certainty is remarkable, at least in my experiencein terms of measurements that are made out in the environment.At least in statistical terms, it is a very impressive correlation, andit is very convincing.

But in some ways these facts-because I think the temperaturerise and the gas rise are really facts that are not really debated-still beg the question. Is there a link? Can we establish a definitelink between the rise in the greenhouse gases and the rise in tem-perature? You have heard evidence here from several of the wit-nesses, including those who were involved in the Bellagio-Villachmeetings, that concludes very strongly that, indeed, a link doesexist, that there is a strong body of convincing evidence that weare heading into an early greenhouse effect, and that warmingrates exceed anything that we have ever experienced before by alarge margin.

Now, I realize that there are people who are still doubters, and Ithink it is always healthy. Having been through the ozone deple-tion issue in the mid-1970s, as have Senator Domenici and SenatorBumpers, I'm aware of this problem. How do we make decisionswhich have potentially enormous consequences in the face of someuncertainty?

Well, let me suggest that in this particular case, if I may use ananalogy, that the findings to date suggest to me that our society islike a high-speed automobile that has just seen a traffic light way

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down the road change from green to amber. I would argue thatwhat we should do-we have two impulses when that happens. Thefirst, of course, is to step on the gas and see if we can beat thelight. I would suggest that we not follow that impulse, that insteadof doing that, that we slow down. And if we are fortunate enoughand we slow down in the right way, the light may again turn greenby the time we reach the intersection. If we don't follow that strat-egy, we may get to the intersection and our whole economy may beup against a full stop.

I believe that we can begin now, even with the uncertainties, tobegin taking precautionary action. These actions need not be dras-tic. They need not be disruptive of our economy or of the economiesof other nations of the world. Some of these actions are already un-derway and many of them will have multiple benefits.

It has already been mentioned, for example, that chlorofluorocar-bons contribute to the greenhouse warming effect. Now, the Mon-treal Protocol says that we will all agree to cut these by 50 percentby 199. Oneofthethings we have to be certain of is that the gasesthat will be substitutes or the chlorofluorocarbons that we are nowusing, which will be designed to protect the ozone layer, that thosegases, those substitutes, will not be released into the atmosphere ina way that will increase the greenhouse effect. There has been vir-tually no discussion of that particular possibility, and I think it is amatter of some concern. We could accelerate the rate at which wephase out chlorofluorocarbons, and we could also recapture andreuse chlorofluorocarbons.

I am shocked to discover that every spring I get a notice from myautomobile dealer urging me to come and have my air conditionerflushed out and to have the chlorofluorocarbons replaced. That isan absolute, total waste of chlorofluorocarbons in most cases be-cause most air conditioners don't need to be flushed out. They onlyneed to be flushed out if there has been a problem. And yet, it's avery effective way of marketing.additional chlorofluorocarbons.

So, there are very simple things we could do to reduce chloro-fluorocarbons, not that that one item is going to solve all the prob-lems. But there are some things like that we should take a look at.

Promoting energy efficiency has been mentioned as an optionthat we should be engaged in. Certainly it is the fastest and mostcost effective method of reducing the rate of carbon dioxide emis-sions, and it's essential to use our fossil fuels more efficiently.And I think we have to look at both end-use efficiencies, lighting,automobiles and the like, as well as production efficiencies. Andthere are some very exciting new technologies which will mark theproduction of electricity, for example, much more efficient than itis now even when we are using highly carbon dioxide producingfuels such as coal.

It is sobering to note that an average new American automobilewhich meets the CAFE standards, if driven 10,000 miles a year,which is roughly the average that a car is driven in this country,that during the year it is being driven, it will release into the at-mosphere its own weight in carbon as carbon dioxide. It's an enor-mous amount, on the order of a ton or more of carbon, that will bereleased. Yet, we know that there are cars being sold in this coun-try right now that get double the gas mileage of the CAFE stand-

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ard, and there are additional automobiles in the prototype stagewhich are on the road now, unfortunately mostly in other coun-tries, that can get three or four times the gas mileage of the CAFEstandard in the United States.

I should point out that energy efficiency may, in fact, improveour productivity. Japan produces a dollar of gross national product,or the equivalent in yen, with using about half of the energy perdollar of GNP as we produce. And I think there is a lesson in thatin terms of their efficiency.

We need to move fairly rapidly into renewable energy technol-ogies. We need to accelerate the development of those. And I thinkit is an obligation for wealthier nations like the United States tocarry out the necessary research. We have cut way back in, thatkind of research over the last few years. Yet, it is very clear thatthe United States and a few other nations are the only ones whocan afford to do that kind of research into renewable technologiesthat do not add to the greenhouse effect.

Not only will this investment increase our economic competitive-ness, but it will also make possible the economic development ofthird world countries.

And I might just add that since I put this testimony together, Iwas speaking with Gus Speth, who is the president of the WorldResources Institute who is just back from a trip to Japan andChina. And he had a meeting with people in Japan at MITI, whichis the organization that has been so successful in bringing togethergovernment and business in Japan. They are actively beginning tothink in these terms and are viewing this as a potential market.That is, if the greenhouse effect is really going to be a major issue,they see themselves poised as havn the products, the energy effi-cient automobiles, the energy eicient light bulbs, for example,which unfortunately are not made in this country, but are mhde inJapan and Europe, to be able to move into those markets very rap-idly. And they see it as a business opportunity. I think there is,again, an important opportunity for us economically in the samewa ....

L need to examine fuel switching and the efficiency with which

we use high carbon-emitting fuels. As I'm sure all of you haveheard before-and I know that Senator Ford may not be happy tohear this again-that coal produces about twice the carbon dioxidefor the amount of energy that we obtain from it as does naturalgas. It is clear that we are not likely to stop using coal, since it isour most abundant fossil fuel, but we should probably think interms of reserving the use of coal for ways in which it can be moreefficiently used. If we attempt to move in the direction of syntheticfuels, the problem becomes even worse. And particularly if wemake synfuels from coal, we end up producing in many cases threeor three and a half times the amount of carbon dioxide per unit ofenergy that we get back compared to natural gas.

I think it is important to take a look at pricing options because itis very clear that in terms of using fossil fuels efficiently, we usethem much more efficiently when prices were rising rapidly thanwe are using them right now. We need to take a look at pricingoptions, tax options, fees, market options, that would be most effec-tive in reducing the greenhouse emissions from particularly fossil

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fuels. And I think in this we could learn a great deal from the Eu-ropean and Japanese experience where the price of gasoline, for ex-ample, in West Germany is double that in the United States, andin Italy it is three times what it is in the United States. And virtu-ally all of that is due to extra taxes. And it does have a significanteffect on the rate at which we use these fossil fuels. That is obvi-ously going to be controversial, but it is something that we reallymust take a look at and decide whether or not it is important tostop using as much fossil fuel. This is certainly one way in whichwe can help achieve that through the marketplace.

I would echo George Woodwell's statement that we need to lookat forestry and reforestation as an important direction to go.

And in answer to an earlier question about nuclear power, cer-tainly I think we should reexamine the nuclear option. But I thinkmost people don't realize what a small fraction of total energy pro-duction electricity is in the whole world. No one of these things Iam suggesting can solve the whole problem. Each one may be ableto contribute something to it. And so, I think we do have an obliga-tion to look at all of them.

To conclude, I would just say that the options I have suggestedcan be implemented as a precautionary means of slowing globalwarming while we increase our understanding of the issue. I wantto emphasize that there is still a great deal of needed field and lab-oratory research in order to understand the sources of some ofthese greenhouse gases. As was mentioned by a couple of the earli-er witnesses, we need to do considerable development of the cli-mate models to make them better predictors because I think as thisprocess goes along, we're going to be constantly wanting to fine-tune our policies and we're going to need those models in order tobe able to know where we are and where we are heading.

Finally, we need to expand our monitoring efforts in order todetect at the earliest possible time an unequivocal connection be-tween greenhouse gases and climate change. I think it has reallybeen very dramatic what the discovery of the Antarctic ozone holehas done to people's willingness to accept depletion of stratosphericozone from chlorofluorocarbons. And it is because there was a realmeasure out there that people could look at. Unfortunately, it is ameasurement of a phenomenon that will-well, I heard a groupdiscussing this. Someone said it would take 100 years to heal evenif we stopped producing chlorofluorocarbons now. And Sherry Row-land who was there said, oh, you're an optimist. A hundred years isthe optimistic view. We expect it will probably take 300 yearsbefore it will heal itself.

The greenhouse effect is likewise one of these largely, at least onreasonable time scale, irreversible effects. So, I think it is impor-tant that we make some changes now, to begin shifting resourceswithin the fiscal year 1989 Federal budget to support research thatneeds to be done, and to begin attempting to implement some ofthese policy suggestions which I and others here have made. Ithink these strategies have the advantage that not only do they ad-dress the greenhouse effect, the also address acid rain, urban airpollution, stratospheric ozone depletion. And I think it is thesemultiple benefits that we will get by moving to energy efficiency,

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phasing out CFC's faster and so on to which greenhouse effectmakes just a more compelling case.

I would agree with George Woodwell that we have an importantopportunity for the United States to provide leadership on the fullrange of global change issues that face us, and that the changesthat are being suggested will, in fact, help provide responsible solu-tions to the problems that have been raised.

Thank you, Mr. Chairman.[The prepared statement of Dr. Moomaw follows:]

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WORLD RESOURCES INSTITUTEA CENTER FOR POLICY RESEARCH

1735 New York Avenue, N.W, Washington, D.C. 2006, Telephone. 202-6386300

Testimony of

Dr. Willias I. Noomaw. Director

Climate, Energy and Pollution Program

World Resources Institute

presented before the

Committee on Energy and natural Resources

United States Senate

June 23, 1988

Senator Wirth, I wish to thank you for the opportunity to

testify at this hearing.

The testimony presented by those who have preceded me

represents a truly remarkable consensus. The evidence is

conclusive that atmospheric levels of carbon dioxide and other

greenhouse gases are rising inexorably as the result of human

activity. The majority of this increase is associated directly

or indirectly with the combustion of fossil fuels along with

significant contributions from chlorofluorocarbon release,

I

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deforest&tion and agriculture.

The data presented by Dr. Hanson convincingly demonstrates

that the global average temperature is indeed rising by an amount

that exceeds expected fluctuations from the climatic mean. The

implication of this analysis is that the global climate is

warming. How confident can we be that this warning is really

taking place?

As a physical chemist who has carried out basic research in

the laboratory where I can control most of the variables, I am

used to obtaining data that is correlated in some fashion at the

95-99 percent confidence level. My experience in field research

on acid rain is that natural variability over which one has no

control yields data that is, at best, significant at the 63

percent confidence level. Hence, Dr. Hansen's finding of a

global temperature rise at his reported level of statistical

significance is truly impressive -- and convincing.

But, in some ways, these facts beg the real question. Is

the observed global temperature rise caused by the increased

concentration of greenhouse gases?

The report which you heard from the Bellagio Villach

meetings concludes that there is a strong body of convincing

evidence that we are heading into an early greenhouse effect with

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warming rates that exceed anything we have yet experienced.

What these findings say to me is that our society is like a

high-speed automobile that has just seen a traffic light far down

the road change from green to yellow. I would argue that we

should respond to this caution signal by slowing down rather than,

by accelerating and attempting to run the light before it turns

red. To press the analogy further, if we slow down far enough in

advance, the light may have again turned green by the time we

arrive at the intersection. Otherwise, our economy may come up

against a full stop.

I believe that we can begin to take precautionary action

now. These actions need not be drastic, nor need they be

disruptive of our economy or of the economies of the other

nations of the world. Some actions are already underway and will

have multiple benefits.

1. Reduce Chlorofluorocarbons

The Montreal Protocol on Substances that Deplete the Ozone

Layer will reduce CFC emissions to protect stratospheric ozone,

but we must be certain that the substitutes -- that may also be

released into the atmosphere -- do not contribute significantly

to global warming. We should also examine ways to capture and

reuse CFCs and find ways to eliminate their use on an accelerated

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150

schedule.

2. Promote snerii EfficlencI

The fastest and most cost effective method of reducing the

rate of CO2 emissions is to use our fossil fuels more

efficiently. Both end-use and generating officiencies can be

improved greatly in the near-term. It is sobering to note that

an average new American automobile driven 10,000 miles per year

will release its own weight in carbon as C02 into the atmosphere.

Yet cars getting double that mileage are for sale in the U.S.

this year and prototype automobiles which are three to four times

as energy-efficient are being tested on the road right now.

I should point out that Japan currently produces more than

twice the GNP for each energy unit as does the U.S. so there is

much we can still do in this area.

3. Renewable Energy Technolo-g

We need to accelerate the development of renewable energy

resources. It is an obligation for wealthier nations like the

U.S. to carry out the necessary research. This will not only

increase our international economic competitiveness, but will

also make 'possible economic development in an environmentally

sound way for third world countries.

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4. Fuel Switching

We need to examine options for switching from high C02 -

emitting fuels like coal to low C02 -emitting fuels such as

natural gas. Since we will certainly continue to use coal, we

should develop technology that will utilize it most efficiently.

It is also critical to avoid synfuel programs which greatly

increase CO2 emissions above those produced by direct burning of

coal, oil or natural gas.

5. PrIcing Optlons

It is necessary to determine which pricing, tax, fee or

market options will be most effuctive in reducing greenhouse

emissions. We can learn a great deal from the European and

Japanese experience of establishing fees which more fully

incorporate the environmental costs of fuel use.

6. Conclusion

The options I have suggested can be implemented as a

precautionary means of slowing global warming while we increase

our understanding of the issue. I want to emphasize that there

is still a large amount of field and laboratory research that

needs to be done to understand the sources of several rapidly

growing greenhouse gases. Considerable development of climate

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152

models also remains to be done so that we can better predict the

consequences of the greenhouse effect in order to best shape

future policies. Finally, we need to expand our monitoring

efforts in order to detect, at the earliest possible time, an

unequivocal connection between greenhouse gases and climate

change. I would hope that shifting resources within the FY89

federal budget to support more global change research would be a

high priority for the Congress. While we need to carry out more

policy research, the options that I have suggested have multiple

benefits in reducing climate warming, air pollution, acid rain

and stratospheric ozone depletion. At the same time these

strategies will improve American economic competitiveness and

enhance our own domestic energy security. We have an important

opportunity for the United States to provide leadership on the

full range of global change issues that face us,. and to help

provide responsible solutions to the problems they raise.

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Senator WiRTH. Dr. Moomaw, thank you very much. We thankall of you.

We have a number of Senators here, and we might move veryrapidly into questions. Let me just first of all ask a short one ofyou, Dr. Hansen, and then ask others to comment if they wouldlike.

I think the question that everybody is asking today with all ofthe heat and everything going on across the middle west and thesouthwest and so on is the current heat wave and drought relatedto the greenhouse effect. And a subpart of that is how sure are youof your response. [Laughter.]

Dr. HANSEN. Well, I mentioned in my testimony that you cannotblame a particular drought on the greenhouse effect. You can say,at least our climate model seems to be telling us, that the green-house effect impacts the probability of having a drought. And inparticular I tried to emphasize that even in the late 1980's and the1990's, the greenhouse effect is already large enough to impact theprobability of having a drought in the southeast and the midwestUnited States.

Senator WJRTH. So, you would say that the heat wave and thedrought is related to the greenhouse effect. Is that right?

Dr. HANSEN. Yes. If you look over a time period of, say, 10 years,the number of droughts you get in that period, it appears that itwill be larger because of the greenhouse effect. But whether youget a drought in a particular year depends upon the weather pat-terns that exist at the beginning of the season, and that is a noisyphenomenon which is basically unpredictable. So, I can't tell youwhether next year is going to have a drought or not. All that weare trying to say is that the probability is somewhat larger than itwas a few decades ago.

Senator BUMPERS. Well, Mr. Chairman, if you would yield onthat just to ask a slightly separate question on the same line. Isthere a correlation between the warming and the amount of mois-ture we get? Are they tied together?

Dr. HANSEN. Yes. That is certainly true, and the answer is differ-ent depending on which part of the globe you're asking about. Atlow latitudes and at very high latitudes, the greenhouse warmingwill tend to increase the amount of moisture both falling and avail-able on the surface. But at mid-latitudes, particularly in thesummer, the answer seems to be the opposite, that there tends tobe a mid-latitude continental drying which Dr. Manabe discussedin some detail.

Senator WiRTH. Dr. Oppenheimer, do you want to take a shot?Any of the others of you want to answer the question? I think it isa perfectly logical question to ask, isn't it? I mean, the Americanpublic is out there. It is getting very, very warm. They hear aboutthe greenhouse effect. It s on the cover of Sports Illustrated. It isthe lead editorial in the New York Times. It is in Fortune Maga-zine, the newest issue, a long study of the implications of this. Andpeople are saying is, in fact, that's what's going on. Are we havingthe drought because of the greenhouse effect? And it seems to mewe have to be in a position of saying yes, no. I suppose there's amaybe factor, or we say yes with a certainty of such and such a

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percent. You all do this day in and day out. Tell us how we respondto that question.

Dr. OPPENHEIMER. I think I would just sort of recapitulate andmaybe restate what Jim and Suki have said which is that no oneepisode, no one drought, no one heat wave can be ascribed uniquelyto the greenhouse warming so that that part of the question has toget a maybe.

But you have to approach the question in a broader context. In-creasing frequency of drought and heat waves is the sort of changethat we would expect as the world warms, and as Jim said, it is thesort of change we might already expect to occur more frequently.But as Jim has noted, as several of us have noted, the global meantemperature has risen over the last 100 years. Four of the last 7years have been the hottest on record, and this year appears al-ready to be headed to be the hottest on record. So, it is reasonableto assume that the greenhouse effect is here. It is happening. Thewarming has begun. It has started. But no one I don't think intheir right mind is ever going to say this one climate event in par-ticular is related.

Senator WIRTH. Do any of the others of you want to comment?Dr. Moomaw?

Dr. MOOMAW. Maybe one way of stating it is that certainly theevents that we have seen in the 1980's and so on are consistentwith all the predictions of the greenhouse effect. That is differentfrom saying that any one event is, in fact, ascribable to it. But it iscertainly consistent with the predictions that have been made.

Senator MCCLURE. Could I ask one question at this point, Mr.Chairman? I think the question is absolutely logical, and I thinkthe probability answer is the right answer. But that doesn't explainthe droughts of the 1930's. Was the drought in the middle 1930's aresult of the greenhouse effect?

Dr. HANSEN. You will notice in the climate simulations which Ipresented we began the simulations in 1958. That was the interna-tional geophysical year. The measurements of atmospheric compo-sition began at that time and have been accurate since that time.

It is more difficult to go back and simulate the 1930s because wedon't know exactly how the climate forcings were changing. Wedon't know what caused the 1930s to be warmer than the precedingdecades. So, it is really difficult to say what caused the droughts inthe 1930s.

Dr. MANABE. May I comment? According to our modern calcula-tions that these model generated drought which we get don't haveto be due to greenhouse gases. So long as you have general warm-ing, you tend to get more of a likelihood of getting mid-continentalsummer dryness. However, a magnitude of-the 1930 was thewarmest. It happened to be a relatively warm period also, as it isat the present time so that from this sense that during a warmperiod you expect more likelihood of dryness. So, in that sense it isconsistent with expectations.

However, when we look at the magnitude of drying which is in-duced by about a half of a degree Centigrade warming, which itwas in 1930-and presently-the magnitude of drying is smallerthan the natural fluctuation of the dry/wet cycle which is inducedby natural cause, not by greenhouse gases so that these drying

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forces are not large enough to say that it is due to the greenhousegases. However, I suspect that the likelihood of this type of mid-continental drying will increase as the warming gets larger andlarger into the next centuries.

Dr. OPPENHEIMER. I would like to make one more point. One ofthe reasons you can get a couple of climatologists out here sayingthat the greenhouse effect has already been detected in some senseis the string of warm years and the general trend. This year, asJim said, is much hotter than previous years so far. I think whatyou will need to get scientists up here to say this particulardrought might be due to the greenhouse effect or it is likely. If thisdrought continues or gets worse or becomes the worse drought everin some sense, then I suspect you would have more people ready toascribe it directly to greenhouse warming.

Senator WIRTH. As a summary point, let me say I have read a lotof studies, met with a great number of the peo pe in this field andhave become convinced myself that the probability of a greenhouseeffect having a significant impact is about 99 percent, and thatwhat we ought to be doing is moving aggressively on programs ofenergy conservation, alternative energy sources, reforestation andso on, and that even if that 99 percent is wrong and the 1 percentis right, those policies of reforestation, alternative energy pro-grams, energy conservation and so on are good for us anyway interms of economic and environmental policy. So, no matter whatwe do, we are going to end up doing the right kinds of things if wecan aggressively pursue that kind of a program as laid out in a lotof the recommendations that you all had today.

And I think it is in pursuit of that with the uncertainty that isout there and doing more research and getting a better sense ofthat,; but we also have to start to understand very clearly what thealternatives are and the policy implications are going to be. And Ithink that is what we are about here.

Senator Ford?Senator FORD. Dr. Hansen, explain something to me if you can. I

live along the Ohio River and Ohio Valley. And that belt throughthere and the south has been getting drier and drier, but the win-ters have become severe. They are not the dry winters. We beenhaving severe winters, and you find the ice and snow in Florida.But from that whole belt south, the winters are becoming verysevere. Now, explain that to me versus the dry summer and theharsh winters.

Dr. HANSEN. I don't think that is very surprising. Now, themechanism for the dry summers in our model is due to the tenden-cy of the ocean to warm more slowly than the land which tends toset up high pressure in the summer over the east coast of theUnited States, and the circulation around the high pressure bringsup warm air northward to the middle west and southeast region.Now, in the winter, as Suki showed on one of his charts, is quite adifferent story. And some warming in the winter, especially at lowlatitudes, tends to put more moisture in the air. And if you are inregions where temperatures are still cold enough for condensation,it is not surprising to get more precipitation and snowfall in thewinter.

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Also, it should be pointed out that the natural variability in the.winter is much larger than in the: summer so that the first placewe look to see-the greenhouse signal is in the summer. So, regard-less of what effects you. predict for the winter, you don't expect tosee those as soon as you do for the summer.

Perhaps Suki would like to elaborate on that.Dr. MANABL There may be some exception in certain regions,

but in general, our model indicates that winter would becomemilder, particularly in high latitudes over Canada and the SovietUnion. And I understand over Alaska, winter temperatures havegone up much more than other places so that I understand yourexperience may not be typical-that is, winters are more severe-because there are many other places where winter has becomemilder, such, as Alaska I understand.

Senator FORD. We are beginning to get the winters now that youused to have in the Great Lakes region.

Dr. MANumE. Pardon?Senator FORD. We are beginning to have in our area the same

type of winters that the Great Lakes region used to have 15 yearsago.

You're going to expect some kind of policy from this group, andit will come out of this committee. And I would like to have asmuch knowledge and as much background as I possibly can.

Now, Dr. Moomaw, tell me which gives the atmosphere moreproblems. Natural gas or nuclear?

Dr. MoomAw. Well, it is clear that natural gas gives more carbondioxide emissions than nuclear power.

Senator FORD. So, you would suggest that we go to nuclear then.Dr. MooMAw. Well, not necessarily.Senator FORD. Well, half of this group, I bet you, a few years ago

was against plutonium. I suspect that many of them who are sit-ting at this table-or several of them anyhow-were against pluto-nium a few years ago. And now we have come 180 degrees.

Dr. MooMAw. Well, not necessarily. I think there is a danger inall of these issues of viewing them one at a time. I think we havemade that mistake just within the atmosphere alone of looking atthe greenhouse effect as though it were something totally unrelat-ed to the acid rain problem or the urban air pollution problem.And I think it is even more important that we not solve one prob-lem at the expense of something else. I think we have to make avalue judgment. And I think the value judgment on nuclear poweris a very important one to make, and it has to be addressed.

I have argued that we need to reassess nuclear power in thiscountry because I in all honesty do not see nuclear power in itspresent form going much beyond the current group of plants that.are already scheduled to be completed.

Senator FORD. Sinc. , you were the only witness that singled meout by name, let me ask you a question. Is there any type of cleancoal technologies that would solve your problem or this panel'sproblem as it relates to emissions of clean air because you aremoving toward acid rain. I listened to you and that's the underly-ing bubble.

And I'm trying to find ways to use the resources that we have.We have an energy policy today that has been laid out pretty clear,

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and that is dependency. That is our. energy policy- todar dependen-cy. And what I want to do is try to take the resources we have andquit depending on other countries. Now how do we use the re-sources we have abundantly that would eliminate your problem asit relates to the greenhouse effect?

Dr. MooMw. I would certainly argue that the resource we havein greatest abundance in this country -is the potential for usingfossil fuels more efficiently. And I think we can actually move-and I will be glad to supply members of the committee with astudy that makes this argument-substantially in that direction inthe very near term at much lower cost than we can either by build-ing any kind of additional power stations regardless of whetherthey are nuclear powered or fossil fuel powered.

In terms of coal technologies,; whieh I think is your direct con-cern, there certainly are new coal technologies that are both clean-er and more efficient than the coal technologies we have beenusing.

Senator WIrTH. If I might just suspend for a moment. We have alive quorum and then a vote on the substitute on the plant closingbill. So, we're going to be I gather about 20 or 25 minutes. Is it thepleasure of Senators to come back?

Senator DOMENICI. I can't.Senator FORD. I can't come back. I've got a 4:30-Senator WIRTH. Do you want jump in very quickly before we go?

Bill was answering that question. I'm sorry. We'll finish thatanswer for the record, if we might, Dr. Moomaw.

Senator DOMENICI. I wasn't here when you all gave your detailedstatements and I am not one who is going to suggest that I had achance to read them because I didn't.

I had an experience in this field, as you already know, many,many years ago quite by accident with Senator Bumpers when wewere both assigned to an innocuous subcommittee that was givento us as freshmen, and it was going to disappear in a year. One ofthe assignments was the fluorocarbons, and we happened to findout then that we had some problems. And from that came the aero-sol issue that was ultimately resolved rather beneficially here andI think it is beginning to be resolved worldwide.

To me it seems that we as a people and probably peoples all overthe world are very skeptical to move in areas such as-this until weeither have a disaster or we have absolute concrete proof of some-thing. And even when we have that, it seems that we need a gameplan of some type. I mean, it isn't going to do a lot of good to theo-rize. We have some tremendous evidence that the earth is warm-ing, and I guess the evidence indicates that that is surely going tocause some real problems for us and for the world. And I assumeyour testimony has indicated that you are getting more and moreconfident that that warming is substantially related to the green--house effect as it applies to gases going up and heat not being ableto leave as it should. Am I correct to this point?

Dr. HANSEN. Yes.Dr. OPPENHEIMER. Yes.Senator WIRTH. Senator Domenici, we have seven minutes left on

the vote.Senator DOMENICI. Did you want to ask a question?

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Senator WIRTH. No. I was going to adjourn the hearing.Senator DOMENICi. Can I adjourn it and take my chances?Senator WIRTH. Why don't you.Gentlemen, thank you very much. We will be back in touch with

you very shortly. I greatly appreciate it and we will leave this toSenator Domenici. Thank you, Pete.

Senator DOMENICI. You want to chicken out because you want toget there. You go ahead. I'll run there and get there. [Laughter.]

Senator Domenici [presiding]. I just want to finish this thought.Therefore, we conclude that we ought to do what we can to inhib-

it the warming. Is that correct?Dr. HANSEN. Yes, that's right.Dr. MOOMAW. Yes.Senator DOMENICI. Have any of you put forth a concrete proposal

which I assume would involve both further investigations and acourse of action? Have any of you individually or collectively putsuch a plan for further evolution of data accumulation andI a sug-gested game plan that might be followed?

Dr. OPPENHEIMER. Let us answer that. This hearing was partlyabout a report which in at least a general way put forward such agame plan.

And I would like to-in response to Senator Ford's questionwhich is really related to this, you don't think about solving thegreenhouse problem by talking about whether we're going to havea total nuclear society in 50 years. That isn't the question. Thequestion is what are we going to do tomorrow. We are not going togo 100 percent to nuclear energy tomorrow even if that were theonly option, which it isn't. There are lots of other options, such assolar energy. The real question is what can we do tomorrow? Andwhat we can do tomorrow, the first step is conservation and effi-ciency. Then let's worry about the longer term.

Senator DOMENICI. Let me just ask my last question. Is part ofyour assessment for us and for those who are trying to establishpolicy-is part of it also an assessment of the incremental increasesin-or the opposite-incremental diminution in this problem bycertain steps? Do we have that?

Dr. MOOMAW. Yes.Dr. OPPENHEIMER. Yes.Senator DOMENICI. So that if this happens we could expect a

minimal positive response and that has been researched sufficient-ly where we have data on that.

Dr. OPPENHEIMER. Nothing is ever researched sufficiently, butthe process is underway.

Senator DOMENICI. What I am very fearful of is that if we have avery difficult problem, it requires a difficult answer. The questionis going to be asked regularly is whether that which we are beingcalled upon to do is going to have an ameliorating effect and howdo you know it is and to what extent. And if we can't get that kindof thing rolling, we are going to do a lot of talking, and we're goingto do a lot of assuming, but we're not going to get this country or

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any country to take the kind of steps that are necessary. So, Iassume the beginnings of a game plan or optional beginnings alsocarry incremental assumed benefits directed at this problem.

Dr. OPPENHEIMER. That's correct.Dr. WooDwELL. Yes.Senator DOMENICI. Thank you very much.[Whereupon, at 4:15 p.m., the hearing was adjourned.]

APPENDIXES

APPENDIX I

RESPONSES To ADDITIONAL QUESTIONS

ENVIRONMENTAL DEFENSE FUND257 Park Avenue SouthNew York, NY 10010(212) 505-2100

July 27, 1988

The Hon. J. Bennett JohnstonChairmanComittee on Energy & Natural ResourcesWashington, DC 20510

Dear Senator Johnston:

Thank you forquestions pursuantgreenhouse effect.

p1616 P Street, NWWashington, DC 20036(202) 397.35001405 Arapahoe AvenueBoulder, CO 8030(303) 440-4901

5655 College AvenueOakland, CA 94618(415) 658-8008

1108 East Main StreetRichmond, VA 23219(804) 780-1297

128 East Hargett StreetRaleigh, NC 27601(919) 821-7793

your letter requesting responses toto my 23 June testimony on theI shall respond in order.

From Senator furkovski:

1) My remarks seen to have been misconstrued bythe questioner. My reference to conservation appliesto conservation of nature, while Dr. Woodwell's refersto energy conservation.

According to several authoritative studies, energyconservation can achieve reductions from current uselevels at a rate of about 20 perreduction of about 50% in energyet al., Ene Z FoA Sustainablefoa Devealont, World ResourcesSuch reductions will not totallywarming but would provide a good

year up to a totaluse (see Goldemberg,Wrld, and &MaInstitute, 1987).avoid greenhousestart at solving the

problem and may save some money along the way, too.

Nuclear fission could provide a non-fossil fuelalternative to produce energy. But the safety, waste,and weapons proliferation issues associated withnuclear fission technology in its current form castdoubt on its ultimate technical and politicalfeasibility. Instead, efforts should focus on thedevelopment of renewable energy sources such as solarphotovoltaics. If private industry would like topursue the nuclear fission option, exploring whetherthe aforementioned difficulties might be overcome, thatoption is open to them. However, given the scale ofpublic subsidies to nuclear energy over the last fewdecades, and given its mixed record, future publicfunding should focus on R&D seed money for renewable.

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There is no physical limit to the potential of renewables as a substitutefor fossil fuel. The limit is one of cost. The objective of an R&D programshould be to bring down the cost. Nuclear, of course, faces this sameobstacle, as well as several others.

2) At the current time, aircraft do not appear to play a significantrole in either the greenhouse or ozone depletion problems. However, futurefleet increases. changes in engine type or altitude of operation could alterthis conclusion. As a result, the potential contribution of supersonic orhypersonic craft to ozone depletion in particular merits detailedinvestigation before any comittments are made.

3) The specific research disciplines I would fund are:

a) ocean heat storage studiesb) ocean carbon cycle studiesc) ozone depletion studies, field and laboratoryd) long-term forest researche) tree responses to pollutant/CO2 enriched atmospheresf) photovoltaic materials

From second list of questions:

1) The current drought and heat wave may or may not be directly relatedto the increasing greenhouse effect. Whether it is or not, the types ofstress we are experiencing such as volatile comodity prices, low rivers,record smog and forest fires, are a foreshadowing of things to come ifgreenhouse gases are not constrained. Such episodes can be expected withincreasing frequency from here on out.

2) We should obtain greenhouse gas reductions wherever we can. Theproblem cannot be solved without carbon dioxide limitation, but controls onother gases are also required. For instance, the Bellagio report notes that areduction of about two-thirds in both. CO2 and non-CO. gases is needed toslow warming to the recent historical rate. Since half the warming comes fromCO2 , a large reduction in that gas can have an important effect,. So can alarge reduction of the other gses in ag g&U but not individually.

3) The global community should move toward developing a framework orconvention for an international response. Such a framework would permit theassessment of scientific information and the evaluation of policy options.After a period of such assessment and perhaps a series of workshops, proposalsfor international protocols to limit emissions may be drafted.

4) We know of no limit to the warming as long as emissions of COcontinue at even half of current levels. Above that level, warming will becontinuous, and there will be no steady state. Even a 500 cut may not beadequate to bring about a steady state. For the U.S., continuous emissions atcurrent levels or higher means continuous change, loss of ecosystems, andprobably loss of farm productivity, wetlands, beaches and coastal

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infrastructure. The security of the nation depends on stabilization of theatmosphere.

I hope these responses are adequate. Let me know if you require furtherinformation.

incerely,

Michael OppenheimerSenior Scientist

MO: p

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Answers to the questions submitted by

J. Bennett Johnston

Chairman, Senate Committee on Energy and Natural Resouroes

Date: August 10, 1988

Question #1: Halting of global warming will require that thegaps between emissions and greenhouse gas sinks be closed. Do wehave the ability to increase the earth's C02 sink oapaoity? Ifnot, what percentage of the burden for controlling global warmingwill fall on reducing C02 and trace gas emissions?

Answer: There is currently a net accumulation annually of aboutthree billion tons of carbon in the atmosphere. This threebillion tons represents the difference between the totalemissions and the total absorption by the oceans and theterrestrial biota. We do not know what the total absorption bythe oceans and the terrestrial biota is globally; we know onlythe net accumulation. The most effective approach to reducingthe imbalance appears to be a reduction in emissions,specifically a reduction in emissions from combustion of fossilfuels and from deforestation. If, however, we wished to increasethe absorption of carbon from the atmosphere to speed the processof reducing the current imbalance, the most effective step wouldbe to increase the area of successional or developing forests.An area of one to two million square kilometers of rapidlydeveloping forest will store in plants and soils about onebillion tons of carbon annually. The storage will continue forforty to fifty years until the processes of respiration and decayreach an equilibrium with gross photosynthesis. At that pointthere is no further storage. Destruction of the forest willrelease the carbon back into 'the atmosphere.

Various other techniques have been suggested, including thepossibility of capturing stack gas effluents, compressing the C02to make dry ice, and sinking the dry ice in the oceans. Suchtechniques require considerable energy and reduce the value offossil fuels as a source of energy.

There is no alternative to a reduction in the sources ofcarbon dioxide and other trace gases.

Question #2: What changes do you feel must be made in park andwilderness area planning to adapt to warming that is already winthe bank"? What scenario do you f9reoast for the nation's publiclands and wilderness areas in the next 50 years? 100 years?

Answer: Assuming that we move rapidly to stabilize thecomposition of the atmosphere and limit the global warming to thetwo degrees or thereabouts expected from the current increases inheat trapping gases, we can expect, in the middle and highlatitudes a change in the mean temperature of three to four ormore degrees centigrade. Such a change is substantial and can beexpected to produce changes in the climatic zones in the range of

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100 to 500 miles with the greater changes in the higher latitudes.Such changes are enough to increase the mortality of treessubstantially throughout North America and to start successionalprocesses leading to quite different types of vegetationthroughout much of the region. The fact that these areas tend toto insular, isolated from one another by agricultural or otherDeveloped lands, means that the migration of species betweenrefuges is problematic. Specific steps may be required to managebiotic resources under these conditions. The steps will have tobe developed within each region. The greatest pressures willoccur in the next 50 years unless we are not successful instabilizing the composition of the atmosphere. In thatcirounstance, there is virtually no action that can be taken toassure the continuity of natural communities. Forests , forinstance, will be destroyed on their drier and warmer marginsmuch more rapidly than they can be regenerated.

Question *3: The greenhouse phenomenon has been well documented,yet little has been said regarding the effect of climate changeon our environment and landscape as we know it. Can you paint usa picture of what the farm belt or sequoias might look like in 50years?

Answer: No simple diagnosis is possible. In general, areas thatare now arable in the farm belt will become warmer and drierduring the growing season. Climatic and edaphio zones nowsuitable for grain crops will migrate poleward; arid zones can beexpected to expand in North America. There is, of course, nopossibility of finding a new Iowa on the Canadian Shield.

I an not able to predict what will happen in a zone such asthat occupied by the redwood trees that you refer to as sequoias.It is possible that the giant sequoias of the Sierra Nevada willenjoy a climate not greatly different from its current climate.The coastal region may be wetter. These, however arespeculative observations based on a very loose interpretation ofmeterologista' models, which are much too general to be usedreliably in such a context. Changes in temperature, however,that lie in the range of 0.10 to 1.0 degree or more per decadeare extraordinarily destructive of biotic systems. Large bodiedslowly reproducing organisms such as trees are at a cleardisadvantage. Forests are severely threatened. The action tocorrect such difficulties is to reduce the cause, the buildup ofgreenhouse gases in the atmosphere.

Question Mq: Dire predictions have been made regarding the fateof U.S. island territories in the Paoifio, nations such asBangladesh, and states like Louisiana, if sea level rise takesplace as believed. Are there any measures that can be taken toprotect these regions? What time frame are we currently workingin?

Answer: The most effective steps involve checking or deflectingwarning. Whatever is done to reduce the warning will not preventincreases in sea level over the next 50 to 100 years. Theincreases are variously estimated as lying between-0,30 of a meterand 1.5 meters, possibly more. Dikes are expensive and notnecessarily effective in areas as large and heavily populated asthe Ganges Delta in Bangladesh. Recognition of the hazards ofliving in such places includes the recognition of the possibilityof storm surges of novel proportions on a continuous basis. Suchlands may have to be abandoned. Such is the cost of our currentpattern of use of global resources.

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Questions for the Panel, submitted for the record from SenatorKurkowski.

Question #l Dr. Woodwell suggests conservation as a means toreach the needed,4O-60 percent reduction in fossil fuelconsumption. Another witness Dr. Oppenheimer concedes that *thegreenhouse effect" is so advanced that 'the very concept ofconservation does not exist in a world that may change sofast...'

- Can conservation alone achieve the necessary reductions?- Is a greater reliance on nuclear energy one of our best

alternatives to dependence on fossil fuels burning?- If not nuclear energy, then what?- What percentage of fossil fuel reductions can we

reasonably expect from the alternatives you are suggesting?

Answer: I an uncertain of the basis of apparent contradictionpresented by Dr. Oppenheimer, who agrees with my suggestion onfossil fuel consumption. Oppenheimer may have been referring tothe conservation of natural communities including the managementof parks and reserves. Management of such areas becomes verydifficult under rapidly changing climate.

My statement about conservation dealt with energy.Improvements in the efficiency in use of energy and in theconservation of energy offer the very best hope for an immediatereduction in the emissions of the heat trapping gases. Areduction in the use of energy from fossil fuels of the order offifty percent is certainly possible over the next years in theindustrialized nations simply by reducing trivial uses of energy,by conserving energy through insulation and the use of moreefficient appliances, through improvements in the fuel efficiencyof automobiles, and through systematic efforts to shift certainuses of energy to reliance on enduring sources, especially solar.The combination of conservation and improved efficiency withinnovations in applications of solar energy can produce a 50%reduction in the total use of fossil fuels in the developednations. In the lesser developed world the challenge may begreater in that the nations of the low latitudes see theirfutures as heavily dependent on increased use of energy. Thereis, however, no reason that the evolution of technology in thosenations must follow the same patterns that it followed in thepresently industrialized nations. There is every reason tobelieve that a much more efficient industrialization is possiblewith heavy reliance on solar energy. Such a transition willrequire further innovations in applications of efficiency in useof energy and in ways of harnessing solar energy. Thoseapplications offer virtually infinite possibilities forindustrial development.

Nuclear energy does not offer immediate promise in solvingthe heat trapping gas problem. Nuclear energy is verycomplicated, expensive, dangerous, and requires a long lead timefor development. My present interpretation of the potential fornuclear energy is that a dollar spent on it would be much better

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spent in developing more efficient uses of solar energy. Thisconclusion is supported by a recent and detailed review of thistopic by William Keepin of the staff of the Rocky MountainInstitute in Colorado.

I an especially troubled that the climatic change problem islikely to be used by the proponents of nuclear energy as thebasis for arguing for a massive program in the redevelopment ofthe nuclear technology. Several factors argue against it. Themost conspicuous is the expense. The least expensive energy canbe developed through conservation and improved efficiency. Myexperience leads me to the conclusion that nuclear energy shouldplay no role in this tradition because of: 1) the intrinsicweakness of the technology, 2) our failure to find a solution tothe high-level waste problem, 3) the hazards associated with theoperation of reactors, 4) the current trend in technology thatseems to be faking energy production by large central powerplants obsolete, 5) the dangers associated with terrorists, and6) the fact that there is no way to guarantee that the very largeinventory of radionuclides in reactors that have been operatingfor even a short time can be contained in a serious accident.

The reactor industry has promoted a most burdensome law, thePrice-Anderson Act, that limits the liability of the industry andof government in the event of an accident. This law puts theburden of the accident on those that happen to be living near thereactor and are most likely to be affected by any release ofradioactivity. Such a law offers the public no confidencewhatever that the. technology is as safe or reliable as theindustry would have us believe.

Question #2: To what extent does fossil fuel used by aircraftcontribute to excessive atmospheric carbon dioxide or ozonedepletion? Does the fact that the fuels are burned aloft resultin aircraft making a proportionately larger contribution to theproblem than say, home heating, automobile emissions, or other*ground levels activities?

- Are there valid scientific reasons for limiting thedevelopment of supersonic or hypersonio transports or otheraircraft that fly higher, farther and faster than current dayaircraft?

Answer: The lower atmosphere, called the troposphere, isthoroughly mixed in a matter of weeks to months and it makeslittle difference at what elevation or in what region emissionsoccur. The upper atmosphere, the stratosphere, usually in excessof 30,000 feet, is partially isolated from the troposphere andnoxious substances such as oxides of nitrogen emitted by highflying aircraft have a longer residence tIme there an a greateropportunity for interacting with the ozone layer. While I an notan atmospheric chemist and hesitate to offer a technical analysisof the chemistry of the stratosphere, I have had enoughexperience in following the problems generated by nuclear weaponsand volcanoes to know that the introduction of particulate matter

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into the stratosphere in any form, as well as changes in thechemistry of the stratosphere# have far reaching implications forclimate. I would take a most conservative approach inencouraging the further development of high flying aircraft thathave the potential for affecting the composition of thestratosphere. The Immediate challenge is to stabilize the ozonelayer, a challenge that under the best of circumstances willrequire decades to a century or more. No steps should be takenthat could in any way compound this problem.

Question #3: If you sat on the appropriations committee and hadthe opportunity to appropriate funds for specific researchdisciplines, what would you fund if you wanted to get a betterhandle on this problem?

Answer: The immediate need is for a rapid reduction in relianceon fossil fuels. That reduction can come through conservation ofenergT. I would seek innovation in ways to reduce the use ofenergy in the industrialized societies. Those innovations cancome through research in universities# various researchinstitutions, and through agencies of government. Virtuallyevery aspect of society is affected, not only those dealingdirectly with energy. I would seek to see the followingsupported:

I. Research on Energy:A. Conservation: how to meet needs for energy with less; tax

and other policies affect this realm. DOE, NSF, Dep't Commerce.B. Effiioenoy: DOE, NSF programs designed to reduce energy

use without reducing services. The research is far-reaching,involves standards of efficiency for household appliances andindustrial equipment as well as technological innovation.

C. Solar: DOE, NSF1. Photovoltaics2. Hot water, air and other solar3. Energy storage systems, especially hydrogen

D. Wind, TidalE. HydraulicF. Other innovations0. Biotic: NSF, DOE, USDA

II. Research on Energy SystemsA. Co-generationB. Transmission LinesC. Domestic and Industrial Systems

III. Research on Indirect Sources of Energy: USDA, DOEA. Improved efficiency in water use, sewage treatmentB. Improved efficiency in transportationC. Efficiency in AgricultureD. Waste TreatmentS. Air conditioning living spaces

IV. Subsidies:After study, subsidies are appropriate to speed the

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development of technology appropriate to support further eoononiodevelopment in the tropics.

V. Population Control:Energy research and conservation measures are nullified

unless population growth globally is slowed drastically.

There is an equally important list of steps to be taken toavoid doing further harm. Those steps include reducing subsidiesfor the further development of fossil fuel sources of energy.The need at the moment is to reduce the availability and use offossil fuels. All governmental and international actions that

-encourage the use of fossil fuels should be reviewed and mostof then revoked.

These are small costs in proportion to military expenses andin proportion to the cost of failure to stabilize the globalhabitat.

Submitted by:

O.K Woodwell, DirectorWoods Hole Research Center

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SU.S Ma. OP MM of CmmCEaiM .e es mm ad AmshvsAdmlm1 it ss

ENVRONMENTAL RESEARCH LADORATOWESGeophysical Fluid Dynamics LaboratoryPrinceton University, P.O. Box 308FCT ," 2Princeton, Ne Jer 04

PIASSE R Mi :: Phone: 609-452-6520 (FTS & Commercial)

August 3. 1988 R/E/GF

Honorable Senator B. Johnston, ChairmanCommittee on Energy and Natural ResourcesUnited States SenateDirksen Senate Office Building - Rm. SO-304Washington, DC 20510

Dear Senator Johnston:

This is in response to your letter of 22 July 1988 requesting nw response toyour questions posed in connection with the hearing of your committee onglobal warming and greenhouse effect.

I have enclosed in thts mail v responses to the two sets of questions fromyou and Senator Murkowski.

Thank you again for giving me an opportunity to testify before your committeeon this important issue.

Sincerely yours,

r94kuro Manabe

encl. 2

171

Response to the Questions from Senator Johnston

Syukuro Manabe

Q. 1) A great deal of attention has focused recently on the relationshipbetween the current drought in the Plain States and the Greenhouse Effect.Do you feel that a correlation exists between the two phenomena? If so, whattype of weather situations can we expect in the next 10 years? 60 years?

A. 1) In nw testimony, I discussed how the warning of climate due to thefuture increase of Greenhouse gases induces a reduction of mid-continentalsoil wetness in summer. Since the increase of global mean surface airtemperature during this century is only several tenths of a degree Celsius,the natural variation of surface hydrology can easily overshadow any summerreduction of soil wetness induced by the warming. However, it is likely thatsevere mid-continental summer dryness will occur more frequently as thewarming becomes greater towards the middle of the next century. The currentdrought has given us a foretaste of what may happen in the future.

Q. 2) Could you explain the cloud feedback process to us in simplified terms?Could the Greenhouse Effect cause an increase in cloud cover through enhancedevaporation rates?

A. 2) Cloud cover exerts a cooling effect on climate by reflecting asubstantial fraction of incoming solar radiation. On the other hand, it warmsclimate by reducing outgoing terrestrial radiation from the atmosphere. Asthe atmospheric circulation changes in response to the warming due to thefuture increase of Greenhouse gases, the global distribution of cloud coverchanges in such a way that one of these two opposing effects overshadows theother, thereby enhancing (or suppressing) the warming. This interaction amongclouds, radiative transfer and climate is called the cloud feedback process.

According to the numerical experiments conducted by various groups, thechange of cloud cover accompanying the warming is quite complex. In responseto the enhanced evaporation, the amount of lower level stratus cloud increasesin high latitudes. However, the total cloud amount is reduced in middle andlow latitudes. As the cumulus convection extends up to higher altitudes, theoverall altitude of high cloud also increases. The net effect of thesechanges is an enhanced warming due to the cloud feedback process.

Unfortunately, the ability of current climate models to reproduce theglobal distribution of cloud cover is far from satisfactory. Although the02-induced changes of cloud cover from various numerical experiments agree

qualitatively with each other, they are quite different quantitatively.Recently, it has been suggested that the increase of liquid water content ofclouds accompanying the warming may increase the reflectivity of theclouds, thereby reducing the warming. Because of the difficulty in modelingthe cloud liquid water variation, this negative feedback effect is notincorporated in most of the current models. Our inability tc develop arealistic treatment of the cloud feedback process. is one of the main reasonswhy our estimate of future warming has a large range of uncertainty.

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Syukuro Manabe Page 2

Q. 3) Are some latitudes or regions of the United States going to benefit interms of precipitation and soil moisture, from changes in the mid-latitudeprecipitation pattern?

A. 3) The impact assessment of a given climate change is not the topic of OWexpertise. Nevertheless, I feel it is important to make every effort to adaptto and exploit future climate change. In a warm climate with higherconcentrations of Greenhouse gases, a larger fraction of precipitation isrealized as rainfall (rather than snowfall) and snowmelt becomes more frequentin Canada and the Northern United States, thereby making soil wetter andincreasing river runoff during the colder half of the year. As I noted in thetext of av testimony, the snowmelt season begins earlier and snow coverdisappears earlier in spring. It is likely that this information may be veryuseful in order to develop a strategy for future management of waterresources.

Q. 4) Should we expect to see a dramatic increase in storm surges andhurricane activities as a result of global warming?

A. 4) Some theoretical analysis has suggested that the frequency of intensetropical cyclones may increase in response to the future increase of seasurface temperature; however, it is essential to confirm this suggestion basedon a comprehensive set of modeling experiments before we can accept such apossibility. Encouraged by the success of our climate model in simulating thefrequency distribution of tropical storms, we have devoted a major efforttoward the study of the influence of greenhouse gas-induced warming on thefrequency of tropical storms. At present the results from this study areinconclusive, but we are continuing to investigate this problem.

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Response to the questions Posed by Senator Murkowski

§yukuro Manabe

Q. 1) Dr. Woodwel1 suggests conservation as the means to reach the needed50-60% reduction in fossil fuel consumption. Another witness, Dr. Oppenheimerconcedes that the 'greenhouse effect" is so advanced that *the very concept ofconservation does not exist in a world that may change so fast...

- Can conservation alone achieve the necessary reductions?

- Is a greeter reliance on nuclear energy one of our best alternatives todependence on fossil fuel burning?

- If not nuclear energy, then what?

- What percentage of fossil fuel reductions can we reasonably expect fromthe alternatives you are suggesting?

A. 1) 1 am not an expert on this topic and would like to refrain fromresponding to this question.

Q. 2) To what extent does fossil fuel use by aircraft contribute to excessiveatmospheric carbon dioxide or ozone depletion? Does the fact that the fuelsare burned aloft result in aircraft making a proportionately largercontribution to the problem than say, home heating, automobile emissions, orother "ground level' activities?

- Are there valid scientific reasons for limiting the development ofsupersonic or hypersonic transports or other aircraft that fly higher,farther and faster than current day aircraft?

A. 2) Again, I am not an expert on this issue. However, I solicited theopnirions of Drs. J. D. Mahlman (Director) and J. Pinto of the GeophysicalFluid Dynamics Laboratory of NAA. Their response follows:

In the troposphere, commercial aircraft generate NOx and CO, therebycontributing to the production of ozone. The expected increase of ozone dueto this mechanism is consistent with the observed ozone increase of 1%/year inthe upper and middle troposphere. It is also expected that such an increaseof tropospheric ozone will contribute to the greenhouse gas-induced warming ofclimate.

Although the emission of NOx from SST and/or HST can alter theconcentration of ozone in the lower stratosphere, we prefer to refrain fromdi!;cussing this issue pending a careful assessment by experts.

Aircrafts probably do not make any significant contribution to C02emissions compared to surface emissions. They can lead to enhanced highcloudiness through condensation of vapor trails.

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,yukuro Hanabe Page 2

Q. 3) If you sat on the Appropriations Committee, and had the opportunity toappropriate funds for specific research disciplines, what would you fund ifyou wanted to get a better handle on this problem.

A. 3) An important research project which deserves high priority is theglobal monitoring of the coupled ocean-atmosphere-land surface system and theactors causing climate change. Such monitoring is essential not only for

providing the input data for a climate model, but also for validating thepredictions of the future climate change and its impact. Persistent andlong-term support is required for this effort.

In addition to the monitoring discussed above, the improvement andvalidation of climate models deserve a high priority. Because of thelimitation of computer resources, the spatial resolution of a current climatemodel is too coarse to satisfactorily simulate the geographical details ofclimate. Furthermore, some of the basic physical processes, such as the cloudfeedback process and the ocean-atmosphere interaction are poorly understoodand crudely incorporated in a model. Therefore, the dedications of majorresearch effort and large computer resources are required in order to improveour understanding of climate and to predict reliably its change.

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RESPONSES TO SPECIFIC QUESTIONS SUBMITTED TO DR. DANIEL J. DUDEKIN REGARD TO TESTIMONY BEFORE THE SENATE COMMITTEE ON ENERGY AND

NATURAL REOURCES ON JUNE 23, 1988 CONCERNING CLIMATE CHANGE

1. What can U.S. farmers expect for the 90's in terms of

cropping cycles as a result of global warming?

As global warming continues, the frequency of drought eventssuch as those experienced this year will increase. Thesestresses will increase the variability of agricultural yields andaffect farm financial recovery. Dryland operations will beparticularly affected as their options to mitigate droughtimpacts are limited. Livestock producers dependent uponfavorable feed prices and limited by the relatively longerproduction cycles are likely to be hardest hit by these changes.Longer term investments in conservation measures will beincreasingly difficult to sustain in the face of climatic change.

Do you believe that domestic agriculture can adapt to the

dramatic changes that may be in store if current warming

scenarios hold true?

Agriculture as we know it will be changed. Croppinglocations and intensity will adjust in response to differentialregional changes. There will continue to be a substantialdomestic U.S. agricultural sector and it is likely to be able tofeed us, albeit at increased prices. However, the U.S. presencein world export markets may be sharply reduced as availablesupplies are used to satisfy domestic demands.

The regional picture is very different from the aggregatenational assessment. The nation as a whole is relatively rich inagricultural resources. However, the intensity of climaticchanges will vary by state and the relative profitability ofagricultural enterprises will be altered in response. There is astrong possibility of large regional shifts in the location ofagricultural production. Consequently, the aggregate picturedoes little to portray the struggles of farmers to retain landpassed down through generations living under a relativelyconstant climate.

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2. You suggest in a recent statement that long-term public

investments such as water resource projects and wildlife refuges

should incorporate climate change assumptions in their planning.

How do you suggest the Energy and Natural Resources Committee go

about achieving this goal in their own project planning?

The first imperative of a changing climate for planning isto abandon assumptions that the climate will be unchanged. Whilethe regional uncertainties of predicted climate changes fromgeneral circulation models is still quite high, hydrologists andothers dealing with inherently uncertain events have developedanalytic methods to test the robustness of project designs.These sensitivity analyses may be of some assistance in decisionmaking while the climate models are improved.

However, a more important consideration is the need todesign and manage projects for flexibility. For example, much ofthe irrigation water in the western United States is notallocated by market processes. Rather, longterm contractsspecifying fixed nontransferrable entitlements at subsidizedprices are the norm. The upshot is inefficent use of theresource and substantial environmental degradation from overdevelopment and irrigation return flows. As climate changes,resources need to be able to be redeployed in response to thesechanges if impacts are to be mitigated. If climate changeresults in surface water supply reductions, water markets canefficiently reallocate supplies as well as stimulate investmentsin more efficient irrigation tech-iology and mangement. Moreefficient water use increases the effective supply and lessenswater mangement trade-offs with in-stream uses and values.Project operating rules could also be evaluated for theirflexibility is responding to altered climatic conditions.

For wildlife, it is imperative that studies be undertaken toidentify potential adjustment corridors to facilitate migration.However, many wildlife managers are faced with existing severethreats to the resource. Additional resources devoted toevaluating changes in critical ecosystem attributes and planningfor climate changt-are required if existing critical efforts arenot to be diluted. The priority is to include the implicationsof a changing climate in land acquisitions. Temperature and flow

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mitigation for fisheries need to be integrated into projectoperating rules.

3. Will increases in plant productivity as a result of higher

* levels of C02 mitigate some, or al.l, of the damage to agriculture

as a result of climate change?

The interaction of C02 concentration increases and climatechange stresses and their implication for crop yields is notcurrently well known. Existing agronomic research has focusedeither on the crop productivity effects of C02 or the impacts ofclimatic change. The joint implications of these simultaneouschanges under field conditions have not been analyzed.Integrating each of these effects in greenhouse, chamber, andfield studies is an area of priority research. ' Some experimentsinvolving detailed computer simulations of plant growth processesindicate increases in some, but not all regions.

In addition, plants vary in their ability to utilizeincreased C02. Crops such as corn and sorghum exhibit muchsmaller productivity responses to C02, but high vulnerability tohigh temperatures and moisture stress. Further, studiesemphasizing climate change effects have only used changes in meanvalues, i.e. changes in the underlying variability of climaticfactors have not been assessed. Consequently, the increasingfrequency of drought and precipitation pattern changes will stillhave significant impacts upon agriculture, no matter theassociated productivity changes. The implication is a highdegree of spatial adjustment between regions.

My own study of the implications of C02 and climate changeswhich'was submitted for the record used estimates of both C02 andclimate change effects from the existing literature. Each set ofeffects was analyzed separately and then combined in an economicmodel of U.S. agriculture adapted from the Economic ResearchService of the USDA. The principal grain and comodity programcrops were evaluated (barley, corn, cotton, oats, rice, sorghum,soybeans, and wheat). The following table summarizes the resultsof that analysis in terms of percentage changes in total U.S.crop acreage for these commodities.

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Table 1. PERCENTAGE CROP ACREAGE CHANGES FROM A 1982 BASE

C02 only Climate Change Only CombinedCrop Acreage Type

Dryland -13% +18% +5%

Irrigated -12% +81 +2%

As the table indicates, the implications for agriculture willdepend significantly on the relative strength of C02 and climatechange impacts as well as their interaction.

It is also important to note that trace gases other than C02are responsible for the other 50% of the warming problem.Consequently, climatic changes equivalent to those caused by adoubling of the C02 concentration in the atmosphere will occurseveral decades before the doubling.

4. Will global warming affect dryland farming in a different

manner than it will irrigated farms? If so how?

As indicated in the testimony by Dr. Manabe, precipitationpattern changes and evapotranspirational changes affect soilmoisture which is critical to the success of dryland agriculturaloperations. His modeling results indicate the possibility ofsevere mid-continental summer dryness. Traditional drylandfarming regions will have few alternatives in the short-run.Farmers faced with these conditions can alter crop mix or type,adopt more drought tolerant varieties, utilize soil moistureconserving practices, and invest in supplemental irrigation. Nodoubt, the land grant system would emphasize both genetic andagricultural practice mitigation research.

Irrigated operations may be better shielded against some ofthe climatic changes particularly those associated with singleseason droughts. However, even irrigated agriculture is notimmune from climate change impacts as precipitation pattern orseasonal changes can affect basic water supplies as well. It islikely that the relative economic importance of irrigated versusdryland farming is likely to be altered with greater emphasis onboth permanent and supplemental irrigation. These changes willplace a new urgency on addressing the problems of nonpoint sourcepollution from irrigated farm operations.

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Would a renewed emphasis on federally funded water projects

(Bureau of Reclamation) help to alleviate reliance on irregular

rainfall patterns?

Since we are facing some climate change no matter whatfuture actions are taken to manage greenhouse gases, mitigationmeasures will play an important role in diminishing the ultimateimpacts from climate change. One of the chief impacts of climatechange may be to alter the spatial pattern of demand forresources, particularly water. It is generally expected thatclimate changes will shift the relative intensity ofagricultural operations northward. This shift will be onto landscurrently important as wildlife habitat, for example, the primarybreeding regions known as the prairie potholes and parklands.Anticipatory expansion of water supply facilities would onlyexacerbate existing resource conflicts and increase the currentenvironmental damage from project construction and operation.

The Bureau has been involved in some nonstructural projectswhich would benefit farmers faced with more variable watersupplies. In the west, a technique known as scientificirrigation scheduling has been developed and applied to theproblem of increasing the efficiency of increasingly scarce watersupplies. This technique involves sophisticated weatherinstrumentation networks, computer modeling, and extensive fieldcontact for calibration on individual fields. The expansion ofsuch weather driven efficiency measures would be mori importantand cost-effective in mitigating climate change impacts thanexpanded dam construction.

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WORLD RESOURCA CNYIR FOR POICY RSERCH

ES INSTITUTE

1735 New %bk Avenue, N.W., W.hInson, D.C. 3M00. relaphon. 20,.384M 00

August 24, 1988

Honorable J. Bennett JohnstonCommittee on Xnergy and Natural ResourcesUnited states SenateWahington, D.C. 20510

Door Senator Johnston:

enclosed are the answers to the follow-up questions submittedby members of the Bnergy and Natural Resources committee.

Z greatly appreciated the opportunity to participate in thegreenhouse hearings and hope that my testimony and responses willbe useful as you and the Committee as you address what I feel tobe the greatest challenge we as a notion end a global society haveever faced.

sincerely,

William 1. HoomawDirector, Climate, Energy and

Pollution Program

v/end.

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Responseto Senator Murkowski's QuestinsDr. Ilifla Mmonaw

lW) Can conservation alone achieve the necessary 50 to 60 percentreductions?

If by "conservation" we mean improved efficiency in theuse of fossil fuels, it is otsugbl for the United States toreduce its fossil fuel consumption by 50 percent. I base myanswer on a comparison with Western European countries whichenjoy a comparable standard of living to ours, but use onlyhalf as much energy per capita as we do, and continue toproduce a dollar of gross national product with half theenergy we require. In fact, the only countries that utilizeenergy less efficiently than we do are the Soviet Union andsome of its allies, especially Poland, China and a handful ofdeveloping countries.

It is important to recognize that Japan and WesternEurope are energy efficient for economic reasons, which is amajor factor in their international competitiveness. Never-the-loss, patterns of energy use play a major role in therelease of carbon dioxide. The U.S. leads all nations with26 percent of the total followed by the Soviet Union with 21percent, Western Europe with 17 percent, China with 11percent, Japan with 5 percent and the developing world - 18percent. (1985 data). By improving the efficiency of ourenergy use, the United States was able to expand its economyby 35 percent between 1973 and 1986 with zero increase inenergy. Modest additional efficiency gains could lead to anactual decrease in energy use.

1b) Is a greater reliance on"nuclear energy one of our bestalternatives to dependence on fossil fuel burning?

Since nuclear power emits no carbon dioxide, it wouldappear to be an alternative to fossil fuels. It is importantto realize that nuclear power is used solely for the produc-tion of electricity in the United States. Energy inputs intothe electrical generation system amounted to 36.2 percent ofour energy use in 1987. This produced usable electricityequal to 11.5 percent of total U.S. energy consumption, theother two-thirds of the total being lost as heat. Of theelectricity produced, nuclear contributed 17.7 percent of theU.S. total or 2.0 percent of our end-use energy. Neverthe-less, because of our heavy use of coal to generateelectricity, approximately 35 percent of U.S. carbon dioxideemissions come from utilities, just ahead of the 30 percentcontribution from the transportation sector.

If all fossil fuel produced electricity in the United

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States were generated by nuclear power, carbon dioxide wouldonly be reduced by about nine percent. Replacing all existingfossil fuel generating stations in the U.S. would require amore than five-fold expansion of nuclear power. At thepresent time, the U.S. has 109 operational nuclear powerplants, 14 construction permits granted, 2 on order and 2,Shoreham and Seabrook, on indefinite hold. The last time anew nuclear plant was announced was in 1977. It is very clearthat how ever one feels about the advantages of nuclear powerfor offsetting the greenhouse effect, the current generationof nuclear technology will not contribute much beyond what italready has to reducing carbon dioxide emissions. It is alsothe case that we actually utilize relatively littleelectricity compared to the direct combustion of fossil fuels.We would also need a major revolution to shift ourtransportation system to electric powered vehicles, and asimilar change in our industrial processes before we couldutilize the expanded output of a nuclear society.

lc) If not nuclear, then what?

On the supply side we can improve the efficiency withwhich electricity is generated so that we release less carbondioxide for each unit of electricity produced. Newaeroderivative turbines developed originally for largemilitary and civilian aircraft promise efficiencies as highas 49 percent when using natural gas, and as high as 42percent when using coal. These would be major improvementsover current steam boiler technology with numerous clean airbenefits as well. Improved cogeneration technology can alsoquickly make a significant contribution to net carbonreleases.

A second near-term strategy over the coming decade wouldbe to return to the mix of coal and natural gas utilized in1973. In the past 14 years, five quads of natural gas werereplaced by an equivalent amount of coal. Reversing thatchange would reduce carbon dioxide emissions by the sameamount as expanding our nuclear power capacity by 50 percentand using this expansion to replace the equivalent amount ofexisting coal plants. A return to gas could be accomplishedat a fraction of the cost of building new power stations ofany kind.

Both of these proposals along with improved energyefficiency are of course part of a strategy for slowing thegrowth of carbon dioxide while we make a transition to non-carbon based fuels. As I have indicated earlier, the currentgeneration of nuclear power plants is not likely to make asignificantly greater contribution that it does at present.If nuclear power is to play a significant role, we are talkingabout the next generation of plants which must be designed to

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meet the safety, proliferation, waste disposal and, perhapsmost significantly, the economic concerns which currentlydiscourage further investment. Even if we began now, thefirst new generation plants could not appear for 10 years, andthey would not be present in large numbers for 20. By thattime we must ask that other energy sources will be available.

At the present time, solar thermal electricity looks farmore promising that anyone would have imagined even a fewyears ago. Several commercial plants are now beingconstructed in California and reportedly in Israel. Costsare said to be comparable to new nuclear plants. Photovoltaictechnology has also improve dramatically in price andefficiency and is now cost competitive with remote diesel

.generated electricity. Another promising application ofphotovoltaic is in the generation of hydrogen fuel.

A West German consortium consisting of Siemans, BMW andthe government are building the first solar photovoltaic-hydrogen facility during the coming year. Both BMW andMercedes have a hydrogen automobile research program andadditional work is being done in the Soviet Union and to alesser extent, in the United States. In appropriatelocations, wind turbines can make a contribution (just ashydropower does) which are now becoming comparable in costwith currently constructed nuclear plants. Although limitedto particular areas, geothermal power, in which the U.S. isthe world leader, can also be a source of non-carbon basedenergy.

Finally, we must examine the role to be played bybiologically based fuels. This is an area that requires closeattention since burning biomass releases a relatively largeainount of carbon dioxide for each BTU of energy generated(approximately 50 percent more than natural gas).Furthermore, the use of energy intensive fertilizers andcultivation techniques can lower the net energy yield stillfurther while releasing more carbon dioxide and depleting topsoil. Despite these potential problems, biofuels themselves,if grown on a sustained basis, utilize the same amount ofcarbon dioxide during growth that they release duringcombustion. To the extent they iiplace fossil fuels in areassuch as transportation, they are likely to reduce net carbondioxide emissions significantly.

Within the next twenty years, each of the technologiesI have described should be a well-established part of ourenergy mix if we support their development now. Nuclear andthe renewable should then be compared on the basis of theirrelative economic costs and environmental and social benefits.

Id) What percentage of fossil fuel reductions can we reasonably

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expect form the alternatives I have suggested?

It is difficult to predict market shares of emergingtechnologies. It does appear that if we continue to improvethe efficiency with which we continue to use energy, andintroduce the technologies and fuel switches I have described,the U.S. could reduce carbon dioxide levels by at least 25percent during the next 20 years. Retiring older, lessefficient coal plants in particular and replacing them withmodern gas turbines, cogeneration and renewables will be themost effective method for introducing these technologies.Instead we have policies which extend the life of existingplants thereby locking us into low efficiency, high pollutionan carbon dioxide emitting facilities.

2. To what extent does fossil fuel use by aircraft contribute toexcessive carbon dioxide or ozone depletion?

a) This is a very interesting question.

Aircraft contribute a relatively small fraction of carbondioxide to the atmosphere. The fact that they deliver it highin the atmosphere make little difference in overall globalwarming. Releasing carbon dioxide at higher altitudes doesmarginally alter the distribution of this gas in theatmosphere and could lead to some slight additional coolingin the stratosphere. Ordinary aircraft have only a very smallpossibility of depleting stratospheric ozone.

b) Are there valid scientific reasons for limiting thedevelopment of supersonic or hypersonic aircraft?

Since both hypersonic and supersonic aircraft fly athigher altitudes that reach into the stratosphere, one shouldexamine their role very closely. both, of these types ofaircraft have the potential for releasing nitrogen oxideswhich have the capability for depleting ozone, but some ofwhich can also tie up ozone depleting chlorine. Carefulanalysis of the specific characteristics of the exhaust needsto be done to assess the overall impact on ozone depletion.Of more serious concern is the addition of water vapor fromthe exhaust of these aircraft to the stratosphere. It wasrecently found that polar stratospheric clouds play a crucialrole in the dramatic appearance of the Antarctic ozone hole.Adding more water vapor to the stratosphere could permit suchice crystal clouds to form at higher temperatures than thosecurrently found mostly over the south polar region. Thiscould lead to much greater ozone loss over the arctic andperhaps elsewhere in the atmosphere.

It is also important to recognize that such high speedaircraft consume enormous amounts of fuel per passenger mile

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and, if the Concord experience is any indication, involveheavy developmental and operating subsidies.

3. If I sat on the appropriations committee..., what areas wouldI fund?

My first priority would be to fund energy efficiencyprograms that can be implemented immediately. I would startwith projects within the federal government in building andauto fleet efficiency, and then make grants to the states tomake their operations more efficient as well. Then I wouldutilize federal purchasing power to create markets for solarand other renewable technologies to hasten their development.I would also support research and development in the fieldsof production and end-use efficiency, solar, hydrogen andother renewables and explore a new generation of nuclearpower. Because nuclear research tends to be so expensive,care must be taken to insure that it does not preempt all ofthe other areas.

Funding of new innovative projects by utilities, schools,hospitals, industries and other parts of the private sectors.There should also be support for a long-term (at least 10years) scientific study and monitoring program in globalclimate change. This program should also provide training foryoung scientists. Policy research should also by supported.Funds should be made available for both our bilateral andmultilateral foreign aid and loan programs to develop energyefficient and renewable energy technologies.

Other options that lie outside of the appropriationsprocess include establishing a carbon tax to discourage theuse of fossil fuels, encourage non-carbon based energysources, and raise revenue to finance the transition to newenergy supplies. One might also wish to examine policies thatwould enhance automobile efficiency and household, commercialand industrial efficiencies. One suggestion is to requirespecified levels of energy efficiency in order to qualifyhomes for a VA or FlA loan.

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Answers to specific questions directed to William R. Koomaw

I. Do you believe that the nation, and in fact the world, aremobilizing sufficient economic, scientific, and politicalresources to properly address the ramifications of globalwarming? If not, what steps must be taken?

No. Despite the fact that global warming from increasedburning of fossil fuels was first described quantitatively 92years ago by S. Arrhenius, we have just begun to realize thefull implications of global warning for society. While thereare many details of global warming that need to be clarified,I believe that there is sufficient certainty over itsdirection and extent that we must begin the transition to aless carbon intensive society.

This transition must be guided by up-to-date science andsound policy analysis. While energy use is directly andindirectly responsible for the bulk of global warming, findingthe sources of methane and nitrous oxide, gaining a betterunderstanding of ocean-atmospheric interactions and measuringthe role of plants in the carbon cycle require furtherresearch. I propose that we commit ourselves to a ten tothirty year scientific research program into global earth andecological sciences that will guide our policy as it evolvesover the coming year. As the stratospheric ozone hole hasdemonstrated, there are likely to be surprises in theoperation of planetary systems, so we must fund a broad rangeof investigations and train and support new scientists inappropriate fields. We must also support policy research,based upon scientific knowledge, that will guide us along theleast economically costly and most effective transition path.

We should begin that transition by implementing rapidlythose policies that are least disruptive to society, but whichprovide large multiple benefits. First on our list ofpriorities should be improved energy efficiency. Since thetransportation sector releases 30 percent and the electricutility sector 35 percent of U.S. COs these are prime targetsfor reduction. Second, a rapid phasing out of CFCs couldreadily be accomplished during the next decade. Third, ashift away from coal toward natural gas could also beaccomplished in to near future. Simultaneously we shouldbegin the transition to carbonless fuels that must be in placewithin the next 20 years. This will require major research,development and marketplace testing of solar thermal, solarphotovoltaic, other renewables including hydrogen production,and an examination of the nuclear option. The latter willhave to be'far more economical and safe than current powerplants to become acceptable.

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2. What has been done in the policy realm to directly quantifythe economic costs to the United States should a globalwarming take place? Are we able to assign numbers to thepossible disruptions to trade, agriculture, commerce, etc. asa result of global warming?

The quantitative analysis of the costs of the greenhouseeffect are just beginning. Studies have been done on the costof sea level rise on Charleston, South Carolina and Galveston,Texas, for example. One can extrapolate costs of dikebuilding in the Netherlands and temporary measures taken alongthe Great Lakes and Great Salt Lake. One can utilize thecosts of this year's drought to estimate the overall cost tocrops, navigation and power generation. The Bellagio reportsuggests that mitigation costs might lie in the range ofseveral hundred billion dollars by 2030. More work needs tobe done, and some is currently underway.

3. If you were to draft a bill outlining three Greenhouse gasreduction policies what would they be in order of importance?

The first would be to introduce energy efficiency intothe society. This would begin with the federal government,extend to the States and move to the private sector throughimproved auto efficiency, building and lighting standards.We can learn a great deal by examining effective andineffective policies introduced in the United States andabroad during the 1970s. One option that should be seriouslyconsidered is a carbon tax that would raise the price offossil fuels enough to encourage their efficient use.

,The second area that would reduce warming significantlywould be to phase out CFCs completely during the next decade.Use specific regulations could be imposed to reduce pure wasteand non-essential uses such as the approximately 19 percentof total CFC release that comes from leaking automobile airconditioners each year. Other policies should place a fee onCFCs to encourage their recycling and early replacement byalternatives.

The third policy that could be implemented rapidly wouldbe fuel switching from coal to natural gas.% A return to thepower generation fuel mix of 1973 would reduce carbon dioxideemissions by as much as a 50 percent expansion of our nuclearcapacity as a replacement for coal. Such a fuel switch wouldbe far less expensive.

These three strategies are clearly transition policies.For the long run we must develop a carbonless energy policywhich relies on solar, renewables and possibly a new, safe,cost effective generation of nuclear power.

.7

APPENDIX I1

ALTERNATIVE-tO COAL COMBUSTION*

Leon Green, Jr.Washington, DC

Abstract. The degree of climatic warming due to-buildup of COw inthe atmosphere may be mitigated by using coal not as fuel but asfeedstock for allothermal gasification by exogenous heat at largecentralized facilities, and controlling the use of the COo there-by produced to sequester it or recycle most of it into the bio-sphere. The CO3 and NH3 produced in such a control system wouldconstitute basic inputs for agricultural or industrial uses atwidely distributed locations. In particular, they, would serve asnutrients for intensive cultivation of biomass which would pro-vide locally produced food, fiber and fuel, or locally generatedheat and power. The central systems could also produce methanolor hydrocarbons as required for ott*er industrial or utility powerand for transportation fuels. High-temperature nuclear processheat technology has been developed in Germany to the point ofreadiness for demonstration of coal gasification. Completion ofthis program is essential if the technology is to be ready fordeployment when the need for positive action to mitigate globalwarming is recognized as critical.

1. Introduction

It is clear that the greenhouse effect and climatechange are real concerns for the condition of theplanet within our lifetime (Mitchell, 1987).

Having ignored earlier warnings of the need for active measures

to prevent global warming due to buildup 9f carbon dioxide in the

atmosphere (e.g., Schneider, 1978: Laurmann, 1979)# the world now

finds itself facing an inevitable further warming of uncertain

degree. It has been estimated that, even if all CO. emissions

were to cease today, there is already enought CO. accumulated in

the atmosphere to produce-an average surface temperature rise of

0.5-1.5 C after equilibration of the oceans in temperature. The

greenhouse effect is now the subject of active investigation by

-Adapted from the introduction to the symposium "Prospects forMitigating Climatic Warming by Carbon Dioxide Control" at theAnnual Meeting of the American Association for the Advancement ofScience, Boston, Massachusetts, February 12, 1988.

(188)

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h. international aentif community, and unswies ot our

current knowledge of the subject have recently been published

(Farrell, 1987; Edmonds, et al., 1987).

2. Possible Mitigation Strategies

*Few of the studies conducted early in this period of increa-

se international activity considered the possible effects of

deliberate human efforts towar& mitigation of the warning trend.

One study by the National Academy of Sciences advised that near-

term preventive action would be premature'and could better await

the findings of ongoing research (NAS, 1983). Even the potential

contributions of yet unknown technologies have been discounted:

"The single largest contributor to future climate change is car-

bon dioxide; no foreseeable technology can deal with the vast

quantities and distributed sources of that essential by-product

of the burning of coal, oil and natural gas" (MacDonald, 1985).

Such a pessimistic conclusion has been challenged more recently

in a study which compared the rates of COa buildup estimated

according to different policy scenarios but which again warned

that "...unless policies are implemented soon to limit greenhouse

gas emissions, intolerable levels of global warming will result"

(Mintzer, 1987).

Since the combustion of fossil fuels is the major source of

COa emissions, constraint on the use of such fuels, particularly

coal, is an obvious measure for limiting these emissions (Rotty

and Weinberg, 1977). Another approach is to recycle carboa from

the atmosphere into the biosphere by global reforestation (Dyson,

1977; Dyson and Marland, 1979; Marland, 1988). However, capturing

89-338 0 - 88 - 7

190

the low concentration of COa in the normal atmosphere by foresta-

tion is a slow process (but one nevertheless well worth initiat-

ing), and coal is far too important a resource to be abnegated.

Scrubbing COm from the flue gas of coal-fired power plants

is technically feasible but, except for special applications, not

economically practical (Steinberg, 1983). Improvements in the

efficiency of end-use energy technologies (Goldemberg, et al.,

1985, 1987; Cheng, et al., 1986) is an obviously desirable

,approach, but one which, like growing trees, requires a long time

for its effect to be manifested. The substitution of nuclear

power for coal-based central station power is an option now sub-

;Ject to a de facto moratorium for reasons which need not be bela-

bored here, and which in any event does not address the problems

of emissions from industrial power and process plants or from use

of transportation fuels.

A complementary approach to limiting CO. emissions could be

to utilize nuclear energy in the form of high-temperaiure process

heat for the gasification of coal or the reforming of hydro-

carbons and to capture the CO2 thus produced in concentrated form

by scrubbing the process stream (Green, 1967, 1968). Some could

then be sequestered in the hydrosphere (Marchetti, 1977) or in

stable chemical compounds, but most of it recycled into the bio-

sphere by photosynthesis under controlled conditions (Green, RE.

cit.). Such an approach wpuld exploit our combined fossil, solar

and nuclear energy resources in an environmentally benign manner.

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3. Nuclear Process Heat

That heat delivered to a chemical process "...can be worth

several times as much as if it were merely supplied to a heat

engine to generate electricity" was emphasized in 1947 by John J.

Grebe of the Dow Chemical Company, who argued that such an appli-

cation of high-temperature nuclear heat would be "...economically

more attractive than more-or-less marginal competition with coal

for power production" (Nordheim, 1947). Two decades later a

respected economist observed that "..the real economic potential

of nuclear fuel is no more captured in its substitution for

fossil fuels in large-scale electric power stations.. .than was

the economic potential of petroleum realized when kerosene repla-

ced whale oil in lamps used in the home" (Schurr, 1968). Despite

the importance of these cited and other similar perceptions,

process applications of nuclear energy never enjoyed the same

priority as power in the development programs of the U.S. Atomic

Energy Commission (Green and Anderson, 1974) or its successors,

the Energy Research and Development Administration and Department

of Energy. Such applications have received only token support

during the past several years, and the effort is now dormant.

Fortunately, development of process heat applications of the

high-temperature reactor have proceeded abroad, in Japan, the

USSR, and especially in the Federal Republic of Germany, where

the principal application investigated has been the gasification

of coal (van Heek, et. al., 1982), sometimes in combination with

other processes (e.g., Barnert, et. al., 1984; Barnert, 1986).

Although the details of the of the FRG program are beyond the

192

scope of this paper, it may be stated in brief that the principal

development problem involved has been materials of construction

for helium heat exchangers immersed in fluidized-bed gasifiers,

design of which can also be improved. The upper operational temp-

erature limit of metallic materials has been established to be

950 C, sufficient for present processes. However, even the FRG

process heat development is now jeopardized by budget stringency

(Klusman and Specks, 1986) and public funding for the ongoing

program at KFA Julich is assured only through 1988. This problem

is compounded by the recent drop in the price of oil and coal,

which has temporarily eliminated the economic advantage of

fission heat vs. conventional fossil heat (Schulten, 1985), thus

rendering nuclear gasification a long-term objective from a pure-

ly economic point of view (Specks, 1987) toward which the KFA

Julich program is now directed (Barnert, 1987). Accordingly, the

environmental desirability of nuclear process heat (Green, 1981)

now constitutes the strongest rationale for its application to

allothermal gasification technology and its essential role in COa

control as outlined below.

4. Carbon Dioxide Control System

Use of exogenous heat to replace the heat generated by coal

combustion in conventional "autothermal" gasification eliminates

the carbon dioxide generated by combustion for which synfuel pro-

Jects have been criticized (e.g., MacDonald, 1987) and leaves

only that produced by the shift reaction in the indirectly-heated

"allothermal" gasifier. Since the gasifier operates at high pres-

sure (about 40 bars) and the process stream is undi uted by

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nitrogen, the COa is concentrated and can be scrubbed from the

stream much more efficiently than would be the case in scrubbing

the dilute stack gas of a coO-fired power plant. °

The gasification and shift steps constitute the first stage

of the COn control system diagrammed in Figure 1. As indicated

therein, a major alternative option is not to shift the mixture

of Co and Ha from the water-gas reaction to COn and more Ha, but

to use it as synthesis gas for producing methane, methanol and

other organic compounds as suggested in -Figures 2 and 3. This

"syngas option" has been studied (Hifele, et. al.? 1986) in a

system which transfers the burden of heat and power generation

heavily from coal to methanol, thus postponing the combustion

of it and other products until the stage of their final use

(Kaya, 1986). Although this system is billed as one of "zero emi-

ssions" of COn, it may be described more accurately as one with

reduced and delayed emissions.

By contrast, the system outlined in Figure 1 can indeed

approximate a "zero emissions" system since, in principle, all

the COn produced can be sequestered or recycled into the

biosphere. To establish the optimum economic vs. climatic balance

among the multiple options offered by the systems of Figures 1

and 2 will require quantification of mass flows by a systems

analysis for which many of the data required are not yet avail-

able. However, it may be surmised a priori that a full transition

to carbonless fuels over the next century as recently proposed by

Hafele (see Barker, 1986) is neither practical nor desirable.

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Hydrocarbons, alcohols and other organic compounds (cf. Figure 3)

are simply too useful for too many human purposes to be abjured.

In the system for effecting maximum carbon recycle (Figure

1) all the intermediate synthesis gas is shifted to COa and Ha.

Ammonia is selected as the hydrogen energy carrier because of its

many uses as a basic agricultural and industrial chemical and

major article of world-wide commerce which is routinely trans-

ported ported by truck, tank car, barge and ship, and which,

like COa, can also be economically transmitted over long

distances in liquid form via pipeline (Green, 1980). For agri-

cultural purposes ammonia can be converted into solid or liquid

fertilizer, dissolved in irrigation water or injected directly

into the soil. It is also a clean-burning fuel whose use has been

demonstrated in piston engines and combustion turbines (Gray, et.

al., 1966; Pratt and Starkman, 1967).

For simplicity, Figure 1 indicates only one feedstock appli-

cation of ammonia: conversion into urea, another compound with

many industrial and agricultural uses including a synthetic feed

supplement for ruminant livestock (Virtanen, 1966; Byerly, 1967).

This application also illustrates one of the multiple routes by

which COa can be sequestered in solid form (Steinberg, op. cit.).

At this point it is worth digressing to note that the use of

urea as a form of aid to developing countries might alleviate the

counterproductive effect of providing food directly, which dis-

courages domestic agriculture and induces movement of farmers off

the land and into overcrowded urban centers. Providing instead a

fertilizer which can also serve as a feed supplement could let

195

the farmers conserve for sale some of their crop otherwise

diverted to fodder and thereby induce them to remain productively

engaged in agriculture. The present paper, however, deals with

biomass technologies applicable primarily by industrialized coun-

tries which are the greatest CO* emitters.

5. Solar Energy Input

Aside from the oceans, the recycling of carbon dioxide into

the biosphere by photosynthesis constitutes the highest-capacity

nonatmospheric "sink" for CO* potentially available. Because of

the immense amount of energy captured annually by photosynthesis

("God's way" of converting thermonuclear energy) this use of CO

to increase the photosynthetic efficiency of plants is also the

most beneficial in that it provides a means for introducing a

very large-scale input of solar energy into the total system.

This objective may be accomplished by diverting massive

flows of chemical energy from the large, centralized gasification

complex (cf. Figure 1 left) to smaller, dispersed operations

(Figure 1 right) which convert the biomass grown thereby into

locally produced food, fiber and fuel or into locally generated

heat and power. It may thus be seen that the system outlined in

Figure 1 contains both "hard" and "soft" energy paths (Lovins,

1976, 1977) and achieves wide distribution of local sites for

energy conversion and use.

From the viewpoint of mitigating the greenhouse effect it

might seem desirable to maximize the solar energy input to

satisfy local heat and power needs by means of the "soft" biomass

cycle (with its "hard" nutrient inputs). on the other hand, the

196

greater the fraction of biomass converted to energy rather than

used to sequester carbon (as wood in lumber products, standing

forests or peat bogs), the more COa nutrient is released into the

atmosphere. The optimum balance is not obvious a priori but will

require further analysis.

6. Biomass Technologies

The dual objectives of biomass technology development are to

produce biomass more efficiently and to use it more efficiently

than is now practiced. Except for the low photosynthetic effi-

ciency of its growth, biomass conversion is by far the most effi-

cient route for utilization of solar energy (Zracket and Scholl,

1980). Improved production is thus both the more important ob-

jective and the one to which nurturing by selective application

of carbon dioxide can contribute.

Wood is man's original fuel, and the technology for its use

has evolved continuously over the ages. Forestry research activi-

ties sponsored by the International Energy Agency biomass program

include investigation of the effect of nutrients on growth, but

not that of carbon dioxide because COm is not conventionally con-

sidered a variable which affects tree growth. This traditional

attitude must change.

There are obvious engineering problems which must be solved

in order to apply the desired Coa amendment to forests. As the

trees grow taller, the more difficult it becomes for a CO-rich

environment to be economically maintained (Allen, et. al., 1985)

even in "conventional" short-rotation forestry. To realize C02-

nurtured growth outside of a greenhouse environment, trees may

197

require frequent coppicing of denoa. plantings- to. produce "wood.

grass* with controlled mlcroeteorology of the canopied space by

careful 'agro-aerodynamic" methods (Lemon, 1967). Alternatively,

Coa nurturing of seedlings in greenhouses with artificial illumi-

nation can shorten the time required for early growth prior to

outplantation (Hanover, 1976).

It should be noted here that intensive cultivation of energy

crops by developed countries need not compete with food crops for

limited land resources; most such, countries have agricultural

surpluses. Marginal land now devoted to needlessly subsidized

agriculture might well be better utilized for energy crops,

especially if it requires irrigation.

On much -otherwise arid land (in, say, the U.S. southwest),

carefully controlled application of water by efficient "'drip"

irrigation methods could exploit the known behavior of plant

species to respond strongly to COa nurturing under conditions of

stress due to water limitation (BJorkman, et. al., 1983). An

energy crop (say, coppiced eucalyptus) would normally require

less water than would most food crops, and the COa amendment

would increase its efficiency of water usage still further.

Given sufficient water, the ultimate factor limiting the

output of plant culture is the photosynthetic efficiency of the

crop (Brown, 1967), and under conditions of intense insolation

the rate of growth of. high-yielding crops is limited by the

availability of Com (Lemon, et al., 1963). This limitation might

be removed by using a *drip" irrigation system to provide water

at night and carbon dioxide by day.

198

Wood, of course, is the energy crop most difficult to

nurture by Coa enrichment for the reason noted above, and other

food and fiber crops are more amenable. A wide program of res-

earch on plant responses to increased carbon dioxide levels init-

iated by the U.S. Departments of Agriculture and of Energy (see

Allen, 1986) emphasizes major food crops such as soybeans (e.g.,

Hrubec, et. al., 1985; Allen, et. al., 1987), the response of

which is shown in Figure 4. Other crops showing good response

include cotton and spinach, as well as aquatic weeds (Spencer and

Bowes, 1986). The possible use of fiber crops cotton and kenaf

(Dempsey, 1975) as CO-nurtured energy crops deserves evaluation.

Another possibly fruitful area of investigation may be

intensive cultivation of algae, for example the filamentous blue-

green Lyngbya (Beer, et. al., 1986), or spirulina, an efficient

protein producer which has been collected and eaten by central

African tribes since ancient times and is now cultivated as a

trendy "health food" in California. A long-range program now

being conducted by the Biomass Technology Division of the U.S.

Department of Energy is aimed at production of microalgae which

when stressed directly fix lipids, potentially direct substitutes

for diesel fuels, and the cell growth of such algae requires

large quantities of COa (Walter, 1987). Biomass growth is not the

author's field, however, and must be addressed by others.

Biomass utilization, on the other hand, is a more familiar

subject. The production of ethanol, oil and other products from

corn is a long-established, large-scale commercial technology

which needs no elaboration here. In the U.S. midwest ethanol is

199

now blended with gasoline for enhancement of octane ratings, and

it is burned "neat" as motor fuel in Brazil. Its use in combus-

tion turbines, like that of methanol, would be straightforward.

Whereas use of fuelwood is ancient, direct combustion of

solid biomass in large installations for industrial and small

utility generation of heat and electric power is a more recent

application, but one which is rapidly spreading in both indus-

trialized and less-developed countries. The key to this rapid

development is the commercial availability of the "circulating"

fluidized-bed combustor (e.g., Schwieger, 1985; Makansi and

Schwieger, 1987; smock, 1987), which is capable of operating

efficiently on a wide range of high-moisture or low-grade fuels

including wood and wood waste, peat, rice hulls, cotton-seed

hulls, bagasse, straw, cattle manure and sewage sludge. Present

wood-burning CFBC boiler installations tend to be in the size

range of 10-50 megawatts (electric), but the upper limit is set

by the radius of economical fuel gathering, not by the conversion

technology.

wood and other biomass can also be thermally gasified by

fluidized-bed techniques to produce low-Btu fuel gas or synthesis

gas using commercial technology, but such gasifiers are generally

restricted to special locations where they are competitive with

natural gas. The largest wood gasification plant reported to date

(Makansi, 1987) produces low-Btu gas at a net rate of about 200

million Btu (ca. 200 billion Joules) per hour for process heat,

or equivalent to a potential power output of about 20 MW(e).

Research on biological gasification and liquefaction techniques

20

for biomass is also underway, but such methods have not yet been

developed to practical status.

In the long run, biomass gasification and liquefaction tech-

nologies will have to be economically competitive with their

equivalent coal technologies discussed earlier. Since the latter

will enjoy economies of large scale, this may prove too high a

hurdle except in special situations. On the other hand, present

commercially-proven biomaps conversion technologies such as

direct combustion and fermentation/distillation will continue to

be utilized for the foreseeable future. Coal-fired power plants

employing circulating FBC boilers now exceed 100 MW(e) in size,

and biomass-fired plants approaching that size may be anticipated

if improved fuel gathering techniques are developed.

7. Time Phasing of New Energy Systems

The history of energy systems reveals that a period of about

50 years is required for market penetration of a new technology

(Marchetti, 1975), and it was noted a decade ago that this rule

indicates "...an immediate need to implement a revised energy

policy if major climatic changes induced by increased amounts of

carbon dioxide are to be avoided in the next century" (Laurmann,

1979). Estimates of the date by which atmospheric COa will have

doubled vary, but a rough mean is about 2050. To achieve signifi-

cant deployment by that time, a new, low-emission energy tech-

nology must therefore be commercially available by the year 2000.

The additional warming effect of other greenhouse gases (Wuebbles

and Edmonds, 1988) makes this timing even more critical (Mintzer,

RE. cit.; Laurmann, 1987).

201

it was mentioned earlier that the development of nuclear

process heat technology, an essential element in the COa control

system proposed here, has progressed in the Federal Republic of

Germany to the point where demonstration of allothermal coal

gasification is the next step. However, it was also noted that

such demonstration i. being jeopardized by efforts to justify

such a step on economic grounds alone. Such a critical develop-

ment must be justified more convincingly as one whose fruition is

not merely desirable but is a bona fide climatic imperative.

Recognition of this fact will come slowly, since public per-

ception of dangers from nuclear reactors is indeed real, whether

justified or not (MacDonald, 1985). Public confidence in techno-

logy "...means that people on Main Street must think it safe..."

(Markey. 1986) and thus requires introduction of new, intrinsi-

cally safe reactors (Beyea, 1986). Nevertheless, despite advocacy

by some of abandoning nuclear energy (e.g., Flavin, 1987), this

recognition will come surely as the fact that the consequences of

unmitigated climatic warming constitute "slow catastrophe"

(Lemon, 1983) permeates the public consciousness.

8. conclusion

The foregoing discussion has envisioned a combination of

fossil, nuclear and solar souTces into a sustainable energy

system capable of controlling net carbon dioxide emissions to the

degree required for mitigation of climatic warming. With two

notable exceptions, the various technologies required for this

system are already available. Still missing at the "front end" of

the system is the demonstration of allothermal coal gasification

202

using high-temperature nuclear heat, but the necessary elements

of the technology are at hand in the Federal Republic of Germany.

Such a development must proceed under high priority if the proce-

ss is to be commercially available by the time when the need for

its wide and rapid application is recognized as critical for the

performance of the required "geohygiene" (Sakharov, 1968).

At the "output end" of the system, further research is

needed to establish the degree of enhancement of biomass growth

achievable by selective COa enrichment of the local environment

of energy crops, to identify which plant species have the best

energy potential and are most responsive to CO3 nurturing, and to

develop techniques for realizing such locally-enriched environ-

ments in practical open-air situations. Commercial technologies

for converting biomass into fuel, heat and power already exist

but can be improved.

The major global COa emitters which will need most to

initiate such "geohygienic" practices are the United States and

other OECD countries, the Soviet-bloc countries, and China, which

is now on the threshold of an intensive, coal-powered economic

development effort. All are fully capable of deploying the tech-

nologies involved, but sufficiently rapid deployment will require

prompt, deliberate national policy decisions. Such a development

will not occur under a "business as usual" scenario determined by

market forces in lieu of policy, since market mechanisms cannot

take the place of government action (Weiss, 1987). Introduction

of the alternative energy technology needed will require "stra-

tegic investments" based upon a (currently) noneconomic criterion

203

analogous to investments in national security (Schneider, 1987)

which, in fact, they will be.

i It is interesting to note in closing that the carbon dioxide

control system outlined above is compatible with a trend away

fiom direct coal combustion already discernible in the U.S.

electric utility industry. No n6w large, coal-fired power

stations are being ordered. Instead, some utilities are tending

to add new generating capacity in small increments in the form of

combined-cycle plants "topped" by combustion turbines burning

natural gas, with the option of installing local, dedicated

(autothermal) coal gasification facilities later if these small

gasifiers become economically competitive. Such gas turbines

could operate equally well on low-Btu synthesis gas, substitute

natural gas (SNG) or methanol produced at large, centralized com-

plexes by allothermal gasification, or on ethanol or syngas

produced in smaller, local distilleries or biomass gasifiers.

Other utilities are adding no new generating capacity of

their own, but are purchasing power from independent cogenerators

or small power producers employing gas-fired combustion turbines

or circulating fluid-bed boilers fired by a variety of low-cost

solid fuels, including wood and wood waste. This trend will con-

tinue as the current restructuring of the electric utility

industry proceeds, and presents an opportunity for introducing

new, low-emission energy technologies which should not be lost.

9. Acknowledgements

The author wishes to thank Roger Dahlman, Christopher

Flavin, Gregg Marland, Michael Robinson and Donald Walter for

204

helpful comments on drafts of this paper.

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Fig. 1. System for Utilizing Fossil, Nuclear and Solar EnergyResources with Maximum Recycle of Carbon (Simplified)

Fig. 2. Variation of System Utilizing Synthesis-Gas Option

Fig. 3. Possible Products of Synthesis Gas Chemistry (courtesyof K. Knizia)

Fig. 4. Mid-day Net Photosynthesis Rate Response of SoybeanCrop Canopy to COa Concentration, Normalized to 330 ppm(from Allen, et. al., 1987)

H20 and Shift CO2 -

SyngasoOption H2

AmmoniaSynthesis NH 3 "E

*Conversion Systems

Biomass: Fluid-Bed Boiler or GasifierNH3 or Ethanol: Combustion Turbine

_.. or Fuel Cell

0'

H20N2

Fossil Nuclear SolarResource Energy Energy

Coal Hat Sunlight

H20 Gasification

Possible UsesMethanation (SNG)

CO+H2- Industrial Methanol, gasolineUses Fischer-Tropsch liquids

Direct reduction of ironEtc.

Shift . CO 2

H2

r W 4 mm mm

L aMydtatel~lll

glyHO synthesisHO-CH2-CH2--OH

Im m

213

CROP PHOTOSYNTHESIS

0 200 400 600 800

CO2 CONCENTRATION, PPM

0

Lu

CAz0

am09LU

Lu

-I

1000