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Environment vs Food. 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. - PowerPoint PPT Presentation
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Environment vs Food
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
Agriculture in Africa
http://go-kids.grolier.com/map?id=mtlr001&pid=go
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
Global Soil Degradation
http://www.utafoundation.org/soil_loss.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
http://photos.mongabay.com/07/trop_defor_bar-600.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
Rainforests of the World
http://www.d.umn.edu/~pask0020/educ5413/mywebquest/Rainforest%20map.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
US Geological Survey 1997
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