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Ag Production and the Environment
Text adapted from
The World Food Problem
Leathers & Foster, 2009
ttp://www.amazon.com/World-Food-Problem-Toward-Undernutrition/dp/1588266389
Erosion
• Soil removed by – Wind
– water
• Agricultural cause: – Plowing
– bare fields• Absence of roots
Wind Erosion
http://soils.usda.gov/use/worldsoils/mapindex/eroswind.jpg
Water Erosion
http://soils.usda.gov/use/worldsoils/landdeg/papers/ersnfig1.jpg
Chemical Degradation of Soil
• Nutrient depletion– Especially if same crop
grown every year
• Salinization– Irrigation with low levels of
salt• Salt build up when dries
• Acidification– Too much fertilizer– Drainage problems– Pollutants– Oil– Pesticides
Salinization
http://www.ciseau.org/cds_upload/1118333201256_Thailande.png
Physical degradation of soil
• Less porous– Compaction by
• Heavy machines
• Animals
• Water logging– Roots die
– Due to• Over irrigation
• Poor drainageSoil compaction
http://www.dpi.vic.gov.au/CA25677D007DC87D/LUbyDesc/Pugged+soil/$File/PUGGED-1.jpg
Extent of Land Degradation
• 38% total cropland degraded worldwide– 2 billion hectares
• 83% by erosion• 12% chemical• 5% physical
• 5-10 million new hectares – degraded each year
• New land must be put into production to compensate– Generally poor qualityOvergrazed degraded soil
http://farm3.static.flickr.com/2097/2138777732_5aa323c591.jpg?v=0
http://soilerosion.net/image/glasod.gif
Irrigation Problems
• Water Quality degradation– Salt-water intrusion in coastal
areas due to lower water table– Leeches salt into groundwater:
unusable– Runoff carries fertilizer,
pesticide residues
• Land degradation:– SoilErosion– Waterlogging– Salinization– acidification
http://www.fao.org/docrep/009/a0409e/A0409E15.jpg
Irrigation in Uzbekistan
Ag Chemicals
• Can lead to – Land degradation– Water pollution– Health problems
• Chemical manufacture can be dangerous– Explosion at fertilizer
plant in Bhopal India in 1984
• Killed thousandsUnion Carbide Chemical Plant, Bhopal India
Fertilizer Runoff: Hypoxia
• Hypoxia– Dead zone in rivers, lakes,
oceans
– N and P fertilizer runoff cause algae growth
– Algal bloom removes dissolved oxygen
– Result: nothing grows
Carrying Capacity
• How many people can earth support?– Carrying capacity
• Limitations on– Agricultural land
– Fresh water
– Waste assimilation
http://www.lunaroutpost.com/gallery/earth/images/globe_west_2048.tif.jpg
David Pimentel
• Believes carrying capacity has already been exceeded
• Earth can support 2 billion– at high standard of living
• Current yields not sustainable
http://ipmworld.umn.edu/vitae/mug/pdmug.gif
Julian Simon
• Optimistic about future ag production– Technology will solve
problems– Drip Irrigation– Fish Farming– GMOs for
• Pest resistance• Drought resistance• Salt resistance
http://www.indefenceofliberty.org/admin/thumbnail/julian.jpg
Fish: the Blue Revolution
• World fish stocks fully exploited– No future increases in wild
capture
• Aquaculture increasing– Developing nations
• China
– Developing nations by 2020 • 79% World population• 77% World fish consumption
https://upload.wikimedia.org/wikipedia/commons/1/10/Global_aquaculture_production_by_country_2010.png
http://photos.mongabay.com/07/world_fish_1950-2000-400.jpg
http://photos.mongabay.com/07/world_fish_1950-2000-400.jpg
Aquaculture
Fish: the Blue Revolution
http://www.theglobaleducationproject.org/earth/image.php?image=f-fisheries-map-lg.gif&title=global%20aquaculture
Global Warming
• Agriculture contributes to global warming:– CO2 released from plant
decomposition• CO2 = 80% greenhouse gases
• No-till Ag releases less CO2
– Methane released from rice paddies• Methane: 23 x warming impact of CO2
– Nitrous Oxide (NO) released from fertilizer use
• NO: 296 x warming impact of CO2
http://picturethis.pnl.gov/PictureT.nsf/All/6GPMKU?opendocument
Global Warming
• Livestock contribute to GW– Produce 18% of total greenhouse gasses
• (Cars, Airplanes, Trains, Boats total 13%)
– Cattle Belching produces methane• 200L/d/cow methane
– 1.3 billion cattle in world
– Occupy 1/3 earth’s landmass
• 5% of planet’s greenhouse gasses
– Manure produces Nitrous Oxide (NO)
– Deforestation to support livestock• Grazing land
• Crop land to grow feed
• 70% of former forest in Latin America is grazing land
http://www.theage.com.au/ffximage/2008/01/22/cow2_wideweb__470x277,0.jpg
Global Livestock Distribution
Global cattle production is projected to double by 2050http://cdn.static-economist.com/sites/default/files/20110730_WOC293.gif
http://gristmill.grist.org/images/admin/globalghg.jpg
(2000)
CO2 Emissions
http://d35brb9zkkbdsd.cloudfront.net/wp-content/uploads/2015/05/Countries_by_carbon_dioxide_emissions_world_map.jpg
http://tomchance.org/wp-content/uploads/2015/03/global-ghg-emissions-figure3-2014.png
http://facweb.furman.edu/~mhuntsberger/blogs/com40spring08/b/wp-content/uploads/global_warming_predictions_map_2.jpg
http://myearthprints.com/wp-content/uploads/2012/10/NASA+arctic+sea+ice+184+20121.png
Global Warming
• Impact on Agriculture:– Flooding of coastal land
• ½ of world population lives within 120 miles of the coast
– Affect crop yields• Increase CO2
– Boosts crop growth– Increase water-use
efficiency• Increase extreme weather• Increase insects, disease• Shift climate zones
– Northern regions better– Tropical regions worse
• Developing countries
Impact on Agriculture
http://www.imf.org/external/pubs/ft/fandd/2008/03/images/cline5.gif
Impact on Agriculture
http://earthtrends.wri.org/images/climate_change_agricultural_potential.jpg
Ethical Issue
• Global warming is caused primarily by CO2 – from industrial development in the
first world
• Is it morally acceptable that the developing world will suffer more negative effects from global warming– Without having benefited from the
fossil fuels that caused the problem.
http://jcwinnie.biz/wordpress/imageSnag/468_pollution.jpg
Solving Global Warming
http://www.zzilch.com/blog/wp-content/uploads/2008/03/combating-global-warming-map.jpg
Bioenergy
• Potential:– Reduce CO2 emissions
• Plants fix CO2
– Sustainable• If use perrennial
switchgrass
– Profits for farmers• Worldwide
– Energy for poor• Worldwide
http://www.iowaswitchgrass.com/__images/Switchgrass-Graphic_800.jpg
Bioenergy Problems• Competes with food production
– Agricultural land diverted– Food prices rise worldwide– Hurts poor hardest
• Undernutrition
• Ethanol from maize increases CO2 production– Farming uses fossil fuel– Less soybeans planted in U.S.
• Tropical forests destroyed to plant soybeans in Brazil.
• Net loss of ability to fix CO2
• Biodiesel from oil palm and soybeans destroys rainforests– Oil palm plantations in S.E. Asia– Soybean planting in Brazil
Oil Palm Plantation, Indonesiahttp://image.guim.co.uk/Guardian/environment/gallery/2008/apr/01/biofuels/[email protected]
http://media.townhall.com/Townhall/Car/b/20080421RZ1AP-BiofuelGauge.jpg
http://cranialcavity.files.wordpress.com/2008/04/ethanolcomic.jpg
Bioenergy plusses and minuses
http://www.fao.org/clim/docs/CDROM/docs/Bioenergy/Bioenergy_Facts_and_Figures_01.pdf