Our Water Resources

Resources and ManThe Malthusian trapThe kinds of resources– renewable resources– Nonrenewable resources– Potentially renewable resources

The nature of exhaustibility

SELF-ACTUALI-ZATION

SOCIAL

SECURITY

PHYSIOLOGICAL

ESTEEM

Food is the most basic of allour needs

MASLOW’S HIERARCHY OF NEEDS

Oceans (71%)

Land(29%)

Most of theEarthiscoveredby water

“...water, water, every wherenor any drop to drink!”

In use

Potentialfarming

Unusable

Potentialgrazing

Cultivated11%

Grazed10%

14%Forests, semi-arid6% Arid

Ice, snow, deserts,mountains (51%)

8%Tropicalforests

Oceans (71%)

Land(29%)

andbarely a fifth of itis available forfarming related activities.

But the supply of land too is limited...

Economic growth exacerbates the demand for water, e.g.,

• with economic growth at 7-10% per year, poultry consumption is rising at the rate of 15% per year in India, Indonesia and China the water demands of this nontraditional industry are only likely to grow;

• we need about 250,000 gallons of water to produce a ton of corn, 375,000 gallons to produce a ton of wheat, 1,000,000 gallons to produce a ton of rice, and 7,500,000 of water to produce a ton of beef.

Farming (41%)Public(10%)

Industry(11%)Power-

Plant (38%)Farming (85%)

Public (6%)

Industry(7%)

Power-Plant (2%)

U.S.A. China

•to which we should also add industry’s needs.

Source: Worldwatch Institute

this comparison of U.S. and China shows how economic growth necessitates increased use of

water for nonagricultural purposes.

How much How much water do water do we have?we have?

http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hyd/smry.rxml

The hydrological cycleIgnoring such long-term effects as the changes in atmospheric storage conditions, run-off filling the ocean basins etc., hydro-logicalcycle ismerelythe re-cycling of waterbetweenland andoceans.

How much water in the hydrosphere?Conventional estimate assumesa total groundwater storage of about 1,700 quadrillion gallons. This gives the estimate of hydrosphere’s total water content as 3.5x1020 gallons.

Oceans (97%)

Ice (1.2%)

Underground water (0.5%)Surface water (0.02%)

Atmosphericmoisture (0.001%)

An alternate assumption is that pores in sediments contain about 80,000 quadrillion gallons of groundwater (almost 50 times the conventional estimate). This yields an estimate of about 4x1020 gallons of water in the entire hydroshere.

Oceans (80%)

Ground-water (19%)

Groundwater (19%)

Ice (1%)Surface water (0.002%)

Atmosphere(0.001%)

Farming (41%)Public(10%)

Industry(11%)Power-

Plant (38%)Farming (85%)

Public (6%)

Industry(7%)

Power-Plant (2%)

U.S.A. China

As is evident from the comparison of water use in the U.S. and China, economic growth necessitates increasing use of water for power generation.

Source: Worldwatch Institute

0.6

0.3

- 0.3

0.0

- 0.61900 1950 2000

Global mean temperature change through the past

century

Source: NOAA and NASA

5-yearrunningaverage

Tem

per

atu

re C

han

ge

(ºC

)

Se

a l

ev

el

rela

tiv

e t

o 1

95

1-7

0 (

cm

)

8

0

4

-12

-8

-4

1900 20001950

5-yearrunningaverage

The global mean sea-level rise through last

century

Source: T.P. Barnett, in CLIMATE CHANGE (IPCC Working Group Report: Cambridge University Press, 1990)

Steric height (dynamic cm

)

Distance off California coast (km)500 400 300 200 100 0

100

95

90

85

80

1985-91

1950-56

0

100

200

300

400

500

0 0.3 0.6 0.9 1.2T (oC)

Dep

th (m

)The 1950-91 hydrographic data off California coast show that

sea surface waters (0-100m) became~0.8oC warmer in the 35-year period between 1950-56 and 1985-91; which

raised the sea level sur-face by 3.1+0.7 cm.

Note: Warming by 1oC the top 100 m of ocean with 15oC temperature and 3.4% salinity should raise the sea level by ~2.2 cm.

Source: D. Roemmich, SCIENCE: v. 257, p.373-375 (July 17, 1992).

80

85

90

95

100

0100200300400500

Distance off California coast (km)

Ster

ic he

ight (

dyna

mic c

m)

Dean Roemmich: Ocean warming and sea level rise along the southwest U.S. coast [Science: 257 ( 373-375), 1992]

1985-1991

1950-1956

Sea surface off California has risen by about 2 cm, on average, between 1950 and 1991

OceansPore water in the

sedimentsIce-caps, glaciers

Rivers, lakesAtmospheric

moisture

Total hydrosphere

Total mass(trillion tons)

1,370,000

330,00020,000

300

13

1,720,313

Share of thehydrosphere

80%

18.8%1.2%0.02%

0.0008%

100%

Considering all sediments*

Total mass(trillion tons)

1,370,000

7,00020,000

300

13

1,397,313

Share of thehydrosphere

97%

0.5%1.4%0.02%

0.0009%

100%

Conventional estimates

The availability of water too is a limiting factor. An average human needs about 300,000 gallons of water annually, including 250,000 gallons for growing food. Indeed, nations with under 150,000 gallons of annual per capita water supply face severe limits to their growth.

Mass of the present hydrosphere

*Karl K. Turekian: GLOBAL ENVIRONMENTAL CHANGE (Prentice Hall, 1996)

Seafood is an important source of animal protein worldwide, nonetheless.

That Climate Thing

•Global warming and its consequences

•The anthropogenic contributions

Number of Fatalities per Event3 30 300 3,000

3

0.3

0.03

Tornadoes

FloodsTornadoesHurricanesEarthquakes

Cu

mm

ula

tiv

e N

um

be

r o

f E

ve

nts

pe

r Y

ea

r

0.1

1

10

0.011 10 100 1,000 10,000

Floods

Hurricanes

Earthquakes

U.S. 20th Century Natural Disaster Fatality-Frequency Plots*

* S.P. Nishenko and C.C. Barton: “Scaling Laws for Natural Disaster Fatalities” in REDUCTION AND PREDICTABILITY OF NATURAL DISASTERS (Eds: Rundle, Turcotte and Klein) (Addison-Wesley, 1996)

* International Federation of Red Cross and Red Crescent Societies (The Economist, Sept 6, 1997)

High wind: 21%

Earthquake: 8%

Flood: 19%

Other naturaldisasters: 21%

Volcanoes: 1%

Drought & Famine: 6%Landslides: 3%

Man-madedisasters: 34%

Disasters*by type: 1971-96

Total: 8,219,000

Tem

pera

ture

Ch

an

ge (

C)

o

0.6

0.3

- 0.3

0.0

- 0.61900 1950 2000

Global mean temperature change through last

century

Source: Thomas Karl and C. Bruce Baker: GLOBAL WARMING UPDATE (NCDC-NOAA, 1994)

5-year runningaverage

1950-60 Mean level

Sea level

rela

tive t

o 1

951-7

0 (

cm

)

8

0

4

-12

-8

-4

1900 20001950

5-year runningaverage

The global mean sea-level rise through last

century

Source: T.P. Barnett, in CLIMATE CHANGE (IPCC Working Group Report: Cambridge University Press, 1990)

Mean 1951-1970 level

20%

0%

- 60%

- 20%

- 40%

Global warming will hurt the poor nations most!

Change in average national crop yield by the year 2,060 compared to yield corresponding to no change in climate

(based on the ocean-atmosphere coupling model) - SCIENCE NEWS, Aug 1992

Ocean Storage1,370,000,000 km3

The Hydrological Cycle

Precipitation285,000 km3

Evaporation320,000 km3

Precipitation95,000 km3

Evaporation60,000 km3

Run-off35,000 km3

Removable volume(in 1012 m3)

4.03.0

10.0

600.00.1

500.01.12.2

56.0220.0

3.38.6

-1.9

1406.7

North America

High plainsSouthwestCalifornia

Africa and Asia

SaharaSahel (soil water)ArabiaAral (Sea: 1960)Aral (groundwater)Caspian (Sea)Caspian (groundwater)

Worldwide

DeforestationWetland reductionDams

Total

Extraction rate(in 1010 m3/yr)

1.201.001.30

1.000.341.602.703.700.770.47

4.900.20

-

19.20

Sea-level riserate (mm/yr)

0.030.030.04

0.030.010.040.080.100.020.01

0.140.01

-

0.54

Estimated sea-levelchange to date (mm)

1.10 0.92 1.20

0.56 0.28 0.89 2.20 3.10 1.30 0.78

3.40 1.30-5.20

11.80

A century of human induced sea level rise*

* Walter Newman and Rhodes Fairbridge: The Management of Sea-level Rise (NATURE, v. 320, p. 319-328, 1986). Dork Sahagian, Frank Schwartz and David Jacobs: Direct Anthropogenic Contributions to Sea-level Rise in the Twentieth Century (NATURE: v. 367, p. 54-57, 1994).

Ocean Storage1,370,000,000 km3

The Hydrological Cycle

Evaporation320,000 km3

Precipitation285,000 km3

Evaporation60,000 km3

Precipitation95,000 km3

Run-off

35,000 km3

In summaryIn summary,, Human ingenuity has defied the “Malthusian Human ingenuity has defied the “Malthusian

Trap”, that Trap”, that the power of population exceeds the power of population exceeds that of the earth.that of the earth.

This has resulted in modifying the most basic This has resulted in modifying the most basic of nature’s processes - the hydrological cycle.of nature’s processes - the hydrological cycle.

Perhaps technology defies the Gandhian Perhaps technology defies the Gandhian dictum, that “nature has enough for our dictum, that “nature has enough for our need, but not for our greed”.need, but not for our greed”.