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Myth
• To feed the hungry we are pushing production onto marginal land– destroying rainforests– causing erosion– poisoning the environment
with pesticides
• Cannot feed the hungry and protect the environment
Environmental Destruction
• 70% of 5.2 billion hectares of ag land is in danger of being turned into desert
• Rain forests will be destroyed in 40 years– At current rates
• Global pesticide use 4.7 billion tons/yr. – 220,000 die each year from
pesticide poisoning
http://whyfiles.org/238earthday/images/brazil_combined.jpg
Amazon Deforestation (purple)
Africa
• Traditional agriculture preserved semi-arid land– diverse mix of crops, trees and
livestock
• 19th century colonists view:– Land is a mine to extract wealth from
• Monoculture of export crops without rotation – quickly depleted soil
• Peanuts, cotton
• Best land for Europeans– worst land for Africans
http://www.hewlett.org/NR/rdonlyres/7C6CC2D1-58A5-4544-B08D-9726E5A35423/0/CottonField.gif
African cotton
Africa
• With independence (1960s)– cash crops needed
• Low prices encouraged more planting
• Livestock displaced to drier lands– increased desertification
• Now pastorialism is equated with poverty
http://children.foreignpolicyblogs.com/files/2007/08/p1.jpg
U.S. Soil Destruction
• 30% of farmland abandoned since 18th century– Erosion– Salinization– water logging
• 1/3 of U.S. topsoil has been lost• 1/2 of U.S. pastureland
overgrazed– erodes at high rate
• Export boom in 1970s– increased erosion in Corn Belt 39% – in three years
Dustbowl 1930s
http://www.ehponline.org/members/2002/110-2/dustbowl.jpg
Iowa Topsoil Loss
• 150 years ago– Iowa topsoil was 12-16” deep
• Now is 6-8” deep
• Current rate of loss: – 10-15 tons/acre/year
http://publications.iowa.gov/1745/1/images/Buffer.jpg
Rain Forests
• Rainforests 7% of land– 50% of plant and
animal species
• Source of – Beauty
– CO2 sink
– Pharmaceuticals– Chocolate, cashews,
bananas, brazil nuts, cortisone, quinine
http://www.wwf.org.uk/picturelibrary/jpeg350/ra/rainforest1.jpg
Amazon rainforest
Rain Forest Destruction
• In 20th century rain forests depleted 50%
• At current deforestation rates– rainforests will be totally cleared
in 40 years
• Amazon is being destroyed at a rate of 20,000 sq miles/year
http://www.unep.org/wed/2007/english/Photo_Gallery/WED_2007/Zoom/PA0176629.jpg
Rondonia, Brazil
• 1980s displaced poor farmers flooded Amazon region– slashed and burned to clear land,
plant crops• Swiden agriculture
– Displaced indigenous peoples
• Most failed after few seasons when land exhausted– Cattle ranchers then moved onto
land
• 1990s: Cattle, Soybeans, Logging destroy forest
http://www.css.cornell.edu/ecf3/Web/new/AF/pics/SlashBurn7.jpg
Slash and burn agriculture
• Rainforest: – rain leaches nutrients from soil
– except those captured by plants
• Forest burned – Ashes rich in nutrients
– Serves as mineral fertilizer
• Farming possible – for a few years
– Then soil exhausted
• Land often used for pasture– Cattle ranchingSlash and burn maize, Peru
http://www.mongabay.com/images/peru/tambopata/Tambopata_1030_5148.JPG
Deforestation: Bolivia
• 80% clearing carried out by large land holders– for cattle, soybeans
• 20% cleared by small farmers
• Thus most of clearing is not to feed hungry
http://www.boliviabella.com/images/bolivia_facts_geography_amazon_deforestation.jpg
Deforestation: Central America
• Most of the tropical rain forest has been affected by:– Logging
– Banana Plantations
– Cattle Ranching
Deforestation: Indonesia
• 1997-8 tropical fires created huge smoke cloud– thousands of square miles
• Fires blamed on poor – clearing land
• Actually, most from – Logging
– plantations http://www.rssgmbh.de/img/projekte/projekte_international/ssffmp3.jpg
Pesticides
• 4.7 billion tons pesticides used worldwide
• 2 billion pounds in U.S. – 25% in California
• Fruits and vegetables
– 30% U.S. use for corn, wheat.
– 25% U.S. use in golf courses and lawns
• Pesticide poisoning in U.S. – 300,000 farmworkers/ yrCalifornia lettuce
http://evolution.berkeley.edu/evosite/relevance/images/pestspray.jpg
Pesticides in Developing Countries
• The most harmful pesticides – are banned in U.S.
• Used, made in developing countries– Without much protection to workers
• Used for export fruit, vegetables – About 50% used for appearances
• Not used for staple crops in developing countries– Expensive– Mixed cropping of staple crops less
susceptible
Pesticides in Developing Countries
• Protection for workers low
• Regulations lax
• Toxicity education poor
Mexican girl drinking from pesticide container
Pesticides
• Despite 10x increase in toxicity– crop losses have doubled
from insect pests
• 0.1% pesticides reaches pests. – Rest into environment
Pesticide Treadmill
• Central America increased cotton production – between 1945-1970
• Boom displaced small scale food producers – resulting in unrest, violence
• Boom made possible by pesticide spraying – for Boll Weevil
• At first, sprayed only few times/season
• Insects develop resistance to insecticide– Requires spraying more
http://www.dep.state.fl.us/waste/categories/cleansweep-pesticides/images/Image5.jpg
Pesticide Treadmill
• By mid-1960s were spraying 10 times/season
• Pesticides killed natural insect predators• Eventually spraying 40 times/season
– costing 50% of production
• Cost too high, leading to Bust• Now wasted, eroded soils
– ghost towns
• Cotton boom- bust increased hunger– left economic ruin– environmental devastation
http://www.sciencemuseum.org.uk/antenna/non-toxiccotton/images/cotton.jpg