260 likes | 372 Vues
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.
E N D
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 Amazon Deforestation (purple) http://whyfiles.org/238earthday/images/brazil_combined.jpg
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 African cotton http://www.hewlett.org/NR/rdonlyres/7C6CC2D1-58A5-4544-B08D-9726E5A35423/0/CottonField.gif
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 • CO2sink • Pharmaceuticals • Chocolate, cashews, bananas, brazil nuts, cortisone, quinine Amazon rainforest http://www.wwf.org.uk/picturelibrary/jpeg350/ra/rainforest1.jpg
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 ranching Slash 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. usein golf courses and lawns • Pesticide poisoning in U.S. • 300,000 farmworkers/ yr California 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