19. Food Production supplementary ie. (mostly)not in text, but see: sec.14.10,14.11, 14.12(4 th ed.)
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Transcript of 19. Food Production supplementary ie. (mostly)not in text, but see: sec.14.10,14.11, 14.12(4 th ed.)
19. Food Production
supplementary ie. (mostly)not in text, but see: sec.14.10,14.11, 14.12(4th ed.)
Feeding the World
1998(millions): 137 born - 53 die = 84 gain (rising) Average life expectancy = ~65 years Earth's population growing >1.5%/yr (NA=0.8%, Malaysia=2.3%)
1 bl Oil = 6 billion Joules=1000kg corn = 125kg beef
Population: 1965 - 3.5 billion 2000 - 6.0 billion 2050 ~10.0 billion (est.)
Doomsday Prophets or Savants ? In~1800(population ~1 billion)Thomas Malthus (economist) wrote "The power of population is infinitely greater than the power in the earth
to produce subsistence for man" and "… the passion between the
sexes is necessary and will remain".
In 1973(population ~3.5 billion) Paul Ehrlich (environmental activist) warned of "… famines of unbelievable proportions" and feeding 6
billion "... is totally impossible in practice"
March 2008 Analysis
• CBC feature
• Of 6 billion people in the world, 1 billion are obese and 1 billion are starving
• Redistribution is needed!!
World Food Requirements WHO estimate = ~2200 Cal/person/day 6 x109 x 2 x 103 = 12 x 1012 Cal/day Food production: 1965: ~2360 Cal/person/day 1995: ~2740 Cal/person/day Supply estimated to exceed demand until 2010 AD
Why are 1billion people in the world malnourished > >>>>Distribution = Politics
www.nationalgeographic.com/ features/2000/population/planet
Wow! Why Worry?
NA = ~15%(Canada = $6200/family/yr, ie.~11%)
Crop yields(bushels/acre): Corn(US) - 25(1800)>110(1980)>130(1990) Wheat(England) - 10(1600)>75(1980) Rice(Japan/Korea/Taiwan) - 4X(1950>1990)
1 North American farmer can produce food for 100 people. Food costs(% of income): W. Europe = >30% Elsewhere = ?!?!
Food comes from the Land
< 4 billion acres* worldwide used for production of food( > 0.8 acre/person). * Dropping ~2%/yr
By 2000 ~5 million acres(India + China) had been degraded so impossible to reclaim, eg. erosion,
overgrazing, deforestation, urban 'development'
(subSahara Africa, Amazon rain forest, even southwestern Ontario).
Just use more fertilizer; $40/acre would increase yield 50%(= 2 billion acres). Cost = $160 billion + pollution.
Distribution of Water in/on the Earth’s Crust
Location Volume(mi.3) %
Oceans Saltwater lakes
Fresh water (easy) Ground(<0.5 mi) Lakes Rivers
Fresh water(hard) Antarctic ice Ground(>0.5 mi) Arctic ice + glaciers
317,000,000 25,000
1,000,000 30,000 300
6,300,000 1,000,000 680,000 325,000,000
97.5
0.3
2.5
(2 x1018 tons)Removal/yr=1000mi3
Annual withdrawal (world-wide):
1900 – 600 km3 2000 – 3800 km3
Water…LKFs (little known facts)
World-wide use of annual replaceable fresh water: in 2000 – 54% by 2025 – 70%(90% in underdeveloped countries)
~70% used in agriculture(irrigation – often inefficient)
See: •worldwater.org •unesco/water/water_links •nationalgeographic.com/ngm/0209
In Canada..the Living is Easy!
Water, Water, Everywhere and…..
Unclean water/sanitation kills ~3 million people/yr (40,000 children/day).
In NA we flush down-the-drain 50,000L/person/yr
Human body(av) 'excretes' ~2.2L/day needs 'to drink' ~1.5L/ day
(also food, metabolism).
10% of world population has
adequate potable water.
Water properties
• Water acts to moderate Earth’s Temperature
• Heat req’d to melt snow and evaporate liq.
• High heat capacity: 1cal/gram/oC
• Unique in that solid is less dense than liquid at 4oC: (ice floats!)
Water Cycle
• Moderates the planet
Water in the USA...(trivia?)Daily use(L)/person Direct(potable!): drinking/cooking -7; bathing - 35; dishwashing -14; flushing toilets - 80; laundry – 35; swimming pools/lawns - 85; other - 90 Indirect: industrial - 3800; irrigation(agriculture/recreation) - 2150; municipal(non industrial) - 550 Total = ~6900 (direct - 380; indirect - 6500)
Annual withdrawal = 2X net natural resupply , eg. the Ogallala reservoir under 8 midwest states has dropped from 58 8 ft 'thick' since 1930.
Water TriviaIt takes this much water to produce:
800L - 1kg vegetables
13000L - 1 steak 80L - 1L gasoline
30,000L - 1 ton paper 100,000L - 1 ton steel
2,400,000L - 1 ton 'rubber')(1 auto = ~300kg of steel)
Most is recycled or 'dumped'(pollution!)
Water – World Supplies
UN minimum requirement per person for drinking/washing/cooking = 50L/day or ~1000m3/yr
A water-stressed country has less than 2000m3/yr/ person of renewable fresh water: in 2000: 508 million in 31 countries, by 2025: 3 billion in 48 countries,eg. India,China(?)
In Canada it’s Everywhere!
OOPS!water-level in Great Lakes drops ~1.2m in last 15 yrs
How Nature corrects itself
• Record snowfalls of 2008 Winter are expected to produce a 1 foot rise in the average water level in the Great lakes
• In a year, 25% of the problem from the last 15 years is corrected
• 1” of rain ~ 1 foot of snow
It has to melt!
• Some lost by sublimation
Not so fast………..
• Only net water gain to Great Lakes if source of snow is not “the lake effect”
• El Nina in Pacific is good : cools NA and moisture evaporates from Ocean- net gain in water levels for NA
Water in Canada
Great lakes holds 20% of the world’s ‘fresh’ water !
But …75% of population, 80% of municipal consumption 90% of industry is American
60% of water runs north into Arctic and ‘unavailable’ Livestock operations in Ontario/Quebec alone produce manure = sewage from 100 million humans Water related illnesses ~10,000/yr; deaths ~ 10/yr
Cost to health care system ~ $300 million/yr
Great lakes: chemical “hot spot”
• 1969 River fire in Cleveland
1972: GL Water Quality accord
• PM Trudeau and Pres. Nixon, alarmed by 1969 fire on Cuyahoga River, sign on
1978 Upgrade
• US /Canada agree to “restore and maintain the chemical, physical and biological integrity of the waters of the Great Lakes Ecosystem”
• Commit to rid GL’s of “persistent toxic substances”-ie those that linger and potentially poison food sources
Biennial Reports
• Started in 1981-still going
• 1987: emphasis placed on importance of human and aquatic ecosystem health
• 43 “areas of concern”
2008 Centre for Disease Control
• Report commissioned by the IJC (oversees issues of GL management)
• 25 “areas of concern”
• Outbreaks of Minimata disease: includes Cerebral Palsy due to Hg poisoning in Thunder Bay, Collingwood, Sarnia, Cornwall
Source of Mercury
• Chlor-Alkali Plants: use Hg in making Cl2 and NaOH. Started in 1894
• 4 cities had large plants (1949-95). 742 tons released
• Electrolysis of salt water: (Hg) used as an electrode
• 2Cl- oxidized (LEO) to Cl2. OH- from reduction (GER) of water . H2 also formed.
Oxidation and reduction
• 2H2O------------------>>H2 + 2OH-
• 2Cl- ------------------------>> Cl2 (g)
• Chloride ion loses electrons, LEO
• H+ ion in water gains electrons GER
• Chlorine and OH- produced
• Na+ is spectator ion (no change)
Chlor Alkali plants
• New tech is available, but not Ohio, Wisc.
Gov’ts reluctant to admit problems
• Health Canada knew in 1990’s
• No public report-leaked in 2000
• Gov’ts fear lawsuits and expensive cleanups
• “there is a reluctance in both US and Canada to admit that there are ANY effects of pollutants on fish, wildlife and human health”
Vital Processes in Food production
(i) Photosynthesis for carbohydrate production
(ii) Nitrogen fixation by plants leads to protein synthesis
(iii)Plants also biosynthesize fatty acids: Canola etc.
We, and the Earth, need our Nitrogen 'Fix'
" The control of all life forms depends on fixed nitrogen to form protein." Inert nitrogen(N2) must be converted to chemically active species, eg. nitrates, ammonia, that can be used by plants and animals to make amino acids/ protein. N2 = :N N: = Inert gas
N2O2 H2
NO32-
nitrate
NH3 (NH4+)
ammonia(-ium)
Nitrogen Fixation - au Naturel
• High energy of lightning + O2 NO NO2 + H2O nitric acid (HNO3) = 'acid rain' • Clover/alfalfa/soy beans(legumes) have N2 fixing bacteria in their roots(nodules). Can add 100lbs/
acre in one year. About equal amounts(1 billion tons/yr each) • Once fixed, the activated nitrogen can be recycled
through dead/decaying organic matter.
Humans cannot 'fix nitrogen' and must consume plants/animals to obtain their requirements.
Nitrogen Fixation - in the Lab
The(Fritz)Haber Process(~1910) - Nobel prize 1918
N2(g) + 3H2(g) 2NH3(g)
First developed for explosives! By 1880s it was recognized that 'active nitrogen compounds' would be necessary as fertilizers to
'feed the world'. By 2000 ammonia is one of the 'top ten' chemicals produced in the world.
#6 in USA, at: 20 million tons/yr
BUT using energy = 300 million barrels of oil
Plant Nutrients
*Primary: (N)nitrogen, (P)phosphorus, (K)potassium Secondary: (Ca)calcium, (Mg)magnesium, (S)sulfur Trace: boron, chloride, copper, iron, manganese, molybdenum, sodium, zinc, (nickel, vanadium)
* can be obtained 'naturally' from manure, guano (bird 'droppings'), bone/fish meal
Non-mineral:
C(CO2), H/O(H2O)
Fertilizers (N, P, K) - the Big Three
Nitrogen/Phosphorus/ Potassium
% of N, P2O5, K2O = the 3 #s on the
box/bag eg. 5 - 10 - 5
(manure = 0.5 - 0.3 - 0.5) As soluble salts, easily assimilated by the plants but easily leached away and not recoverable
Can be quick/slow release Can be complete(all three); straight(one of the three)
Nitrogen (Ammonia / Nitrates) Now almost exclusively by the 'Haber process' Sometimes in the form of liquid/'anhydrous' ammonia (gas, bp.-33oC) but easier/less dangerous as solids/salts. Combined with: Carbon dioxide: (urea - H2NCONH2) Acids: sulfuric (ammonium sulfate - (NH4)2SO4) nitric (ammonium nitrate - NH4NO3) phosphoric (ammonium phosphate - (NH4)2HPO4
Natural sources exhausted / too expensive after ~1950, eg.'Chilean saltpeter'(NaNO3) and 'guano' (Chile/Peru)
Nitrates - too much Bang, too many $$ ?
For how many more decades can we afford the high costs of production (non-renewable energy) and nitrate pollution(non-accountable).
*Commonly used as an explosive, eg. World War I, Oklahoma City, 1995 and elsewhere
*Ammonium nitrate (NH4NO3)
Are we hooked?
Phosphorus (Phosphates)
Recognized in early 1800s, first in Europe, that 'phosphate' was a critical for plants. After skeletons
from battlefields were 'used up', larger supplies were required and in more soluble form, so;
Ca3(PO4)2 + 2H2SO4 Ca(H2PO4)2 + 2CaSO4
superphosphate also from: phosphate rock + phosphoric acid
Largest deposits in Florida and Morocco (2/3 world supply!). Estimated to last for 30 - 40 yrs;
then under Atlantic Ocean off Carolinas.
Phosphate Pollution
• Food for blue-green algae (cyanobacteria) : summer 2007
• Fertilizers, detergents enter natural waters
Potassium
Most common form is potassium chloride (KCl). World class deposits developed in: > Germany, before World War I > USA, eg. Carlsbad, NM > Canada(Saskatchewan, 200m thick & 1.5 km below ground); buy shares(?) in Potash Corp
Used as cation(K+), thus any soluble salt will do.
The Future…….
• What are your views on
• (i) the best Energy sources (and why)
• (ii) solution to pollution
Global Environment
• Some necessary steps• Population control: reduce/stabilize overall
E and food demands• Nuclear power: Clean-low level radioactive
waste buried deep in the ground (its origin); no C emissions. Oil has max 100 years left.
• Make clean technology financially attractive (gov’t initiatives/grants)
The problem with David Suzuki
• Refuses to acknowledge the reality of nuclear power as the future
• France (highest ~60% nuclear) has cleanest air in Europe
• Wind/solar/wave/biomass etc.OK for off grid applications, but not practical for constant large urban needs
Some positive signs
• Ont Gov’t plans new nuclear power facility
• Alberta considers nuclear power option despite “tar sands” resources
• 1 barrel of oil used to produce 2 barrels in Tar sand project (CBC feature March 2008)
• Huge CO2 emitter. Nuclear is the solution
But……..some big negatives
• Alberta tar sands: world’s largest oil resource outside Saudi Arabia
• BUT..requires a lot of Energy to extract it (~ 1 barrel of oil to produce 2 )
• AND-massive environmental destruction
Environmental damage due to Tar Sands projects
• Deforestation
• Tailing ponds
Tailing pond contents
• Most dangerous contaminant is naphthenic acid (PNAH with carboxylic acid bonded to it)
• Process of extraction involves using vast quantities of hot water, naptha and paraffin in order to separate the sparingly soluble butumen from the tar sands
The leftovers!
• Each cubic meter of bitumen extracted produces 3-5 X the volume of aqueous “tailings” that must be stored
• Area the size of Lake Ontario needed!-visible with naked eye from outer space
• Also alkyl substituted PAH’s (carcinogenic) in these ponds
Effects on neighboring communities
• Fort Chipewan (1st nations ; downstream form tarsands projects)
• Greater incidence of cancer, lupus and MS since tarsands development started