Ag Production and the Environment

Text extracted from

The World Food Problem

Leathers & Foster, 2004

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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

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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

http://news.bbc.co.uk/nol/shared/spl/hi/pop_ups/04/sci_nat_feeding_the_world/img/5.jpg

http://photos.mongabay.com/07/world_fish_1950-2000-400.jpg

http://www.ifpri.org/pressrel/2003/20031002.htm

http://photos.mongabay.com/07/world_fish_1950-2000-400.jpg

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%)

– 1.3 billion cattle in world• Occupy 1/3 earth’s landmass

• 20 lb CO2 produced per pound of beef

• Cattle Belching produces methane– 200L/d/cow methane

– 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

  <1    20-50

   1-5   50-100

   5-10   100-250

   10-20    250+

Global Cattle Distribution

All densities are in heads per square Kilometer. http://agtr.ilri.cgiar.org/Maps/distributionMaps/Species/Cattle.htm

Global Cattle Distribution

Global livestock production is projected to double by 2050

http://gristmill.grist.org/images/admin/globalghg.jpg

http://facweb.furman.edu/~mhuntsberger/blogs/com40spring08/b/wp-content/uploads/global_warming_predictions_map_2.jpg

Ice melt in Greenland

http://heartspring.net/images/greenland_ice_melt.jpg

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

USA biggest CO2 emitter

http://www.hyperhistory.com/online_n2/connections_n2/climate_n2/emissions.gif

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.

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Solving Global Warming

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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/GD5160468@This-undated-photo-sh-509.jpg

http://media.townhall.com/Townhall/Car/b/20080421RZ1AP-BiofuelGauge.jpg

http://cranialcavity.files.wordpress.com/2008/04/ethanolcomic.jpg

Bioenergy benefits and challenges

http://www.fao.org/clim/docs/CDROM/docs/Bioenergy/Bioenergy_Facts_and_Figures_01.pdf

Bioenergy plusses and minuses

http://www.fao.org/clim/docs/CDROM/docs/Bioenergy/Bioenergy_Facts_and_Figures_01.pdf