DESERTIFICATIONDESERTIFICATION

By By Jessie Hanson Jessie Hanson

and and Julia HolmbladJulia Holmblad

OVERVIEWOVERVIEW

What is it?What is it?Regions effected by desertificationRegions effected by desertificationCausesCausesImpacts Impacts Current statusCurrent statusPros and ConsPros and ConsSolutionsSolutions

DesertificationDesertification

The transformation of arable or habitable land The transformation of arable or habitable land to desert, as by a change in climate or to desert, as by a change in climate or destructive land use.destructive land use.

Can be natural or humanCan be natural or human--induced (induced (Geographical, Geographical, 20002000))

Desertification is regarded as an environmental Desertification is regarded as an environmental problem of global significance.problem of global significance.Came to global attention about 30 years agoCame to global attention about 30 years ago

Can include…Can include…

Soil erosion Soil erosion River pollutionRiver pollutionDepletion of underground water Depletion of underground water resourcesresourcesInvasion of grassland by inedible shrubsInvasion of grassland by inedible shrubsEt ceteraEt cetera

Regions effected by Regions effected by desertificationdesertification

North AfricaNorth Africa

Central AsiaCentral Asia

AustraliaAustralia

Regions in North and South America.Regions in North and South America.

Regions of DesertificationRegions of Desertification

Causes of DesertificationCauses of Desertification

Human activityHuman activity

Climatic changes (nonClimatic changes (non--human induced)human induced)

Human ActionsHuman Actions

Overgrazing Overgrazing Inappropriate numbers or types of Inappropriate numbers or types of animalsanimalsTrampling of soilsTrampling of soilsReduction of vegetative coverReduction of vegetative cover

DeforestationDeforestationFuelwoodFuelwood gathering gathering Slash and burn farmingSlash and burn farming

OvercultivationOvercultivationEconomic incentives overriding agricultural knowledgeEconomic incentives overriding agricultural knowledgeSubsistence farming (slash and burn)Subsistence farming (slash and burn)

Inappropriate irrigationInappropriate irrigationDessicationDessication of water resourcesof water resourcesSalinizationSalinization of farmlandof farmland

Geographical, 2000

Human ActionsHuman ActionsEstimates of percentage of human actions causing Estimates of percentage of human actions causing desertification are: overgrazing (35%), deforestation desertification are: overgrazing (35%), deforestation (30%), other agricultural activities (28%), overexploitation (30%), other agricultural activities (28%), overexploitation of fuel wood (7%), and of fuel wood (7%), and bioindustrialbioindustrial activities (1%) (Cullet).activities (1%) (Cullet).Human impacts can exacerbate but not initiate Human impacts can exacerbate but not initiate desertification (desertification (SkouriSkouri, 1985), 1985)

Land used for millet cultivation has become barren sand dunes (Eden Foundation).

Climatic EffectsClimatic Effects

Natural global cycles of dry and rainNatural global cycles of dry and rain

Change over significant amounts of timeChange over significant amounts of time

Not induced by human actions, but can Not induced by human actions, but can work in combination with them.work in combination with them.

The Vicious CycleThe Vicious Cycle

Less rain fallsLess rain fallsVegetation diesVegetation diesLand becomes lighter color and reflects more Land becomes lighter color and reflects more lightlightReduced energy absorbed by ground means Reduced energy absorbed by ground means the ground cools. the ground cools. Cooler ground reduces convection effects that Cooler ground reduces convection effects that promote rainfall.promote rainfall.Less rain means drier, cooler, more desiccated Less rain means drier, cooler, more desiccated land.land.Topsoil dries and turns to dust, blows away. Topsoil dries and turns to dust, blows away. (Edwards, 2005)(Edwards, 2005)

Impacts: EcologicalImpacts: Ecological

Accelerated soil erosion by wind or waterAccelerated soil erosion by wind or waterWind erosion can lead to huge dust storms that can Wind erosion can lead to huge dust storms that can circumnavigate the globe. (Ayres, 2003)circumnavigate the globe. (Ayres, 2003)Dust can choke a city, bury an oasis, hasten Dust can choke a city, bury an oasis, hasten desertification in other areas. (Edwards, 2005?) desertification in other areas. (Edwards, 2005?)

SalinizationSalinization--Increased salinity in soilsIncreased salinity in soilsReduction in species diversityReduction in species diversity

Loss of endemic animal and Loss of endemic animal and plant speciesplant species

Reduction in plant biomassReduction in plant biomass

Impacts: EconomicImpacts: Economic

Loss of fertility and productivity in soilsLoss of fertility and productivity in soilsIn China alone, about $6.5 billion annually is In China alone, about $6.5 billion annually is lost to the effects of desertificationlost to the effects of desertificationWorldwide $300Worldwide $300--600 billion lost annually600 billion lost annuallySince 1985, Kazakhstan has lost 12.5 million Since 1985, Kazakhstan has lost 12.5 million acres of grainacres of grain--growing land.growing land.Benefits of prevention and restoration are 2.5x Benefits of prevention and restoration are 2.5x greater than allowing desertification to greater than allowing desertification to continue.continue.

((Larson, 2003Larson, 2003))

Impacts: Human Impacts: Human

Desert lands are inhospitable, Desert lands are inhospitable, sometimes uninhabitable. sometimes uninhabitable. 2/3 of arable land in Africa at 2/3 of arable land in Africa at risk.risk.Loss of arable land means Loss of arable land means increased poverty, famine.increased poverty, famine.Food insecurity leads to more environmental Food insecurity leads to more environmental refugees and displaced persons, more forced refugees and displaced persons, more forced migrations. migrations. People are important, too.People are important, too.

(Larson, 2003)

Impacts: HumanImpacts: Human

The UN Convention to Combat The UN Convention to Combat Desertification Desertification

One of most critical problemsOne of most critical problemsOne billion people in 90 countriesOne billion people in 90 countries

Land and water resources credited with Land and water resources credited with inciting 10 recent armed conflicts in arid inciting 10 recent armed conflicts in arid landslands

(The Ecologist, 2000)(The Ecologist, 2000)

Current NumbersCurrent Numbers

Worldwide, desertification is making approximately 12 Worldwide, desertification is making approximately 12 million hectares useless for cultivation every year. This million hectares useless for cultivation every year. This is equal to 10% of the total area of South Africa or 87% is equal to 10% of the total area of South Africa or 87% of the area of cultivated lands in our country of the area of cultivated lands in our country The reduction in plant cover that accompanies The reduction in plant cover that accompanies desertification leads to accelerated soil erosion by wind desertification leads to accelerated soil erosion by wind and water. South Africa losing approximately 300and water. South Africa losing approximately 300--400 400 million tons of topsoil every year (Collins, 2001)million tons of topsoil every year (Collins, 2001)The Sahara desert is creeping southward at a rate of The Sahara desert is creeping southward at a rate of 1km/year. (Navarro, 2001)1km/year. (Navarro, 2001)

Pros and ConsPros and Cons

ShortShort--termterm

Long Long --termterm

Pros: Short TermPros: Short Term

Increased agricultural production throughIncreased agricultural production through“Consumer” irrigation“Consumer” irrigationPoor farming techniquesPoor farming techniques

Increased economic gains from higher Increased economic gains from higher productionproduction

Cons: short termCons: short term

Loss of fragile desert habitat niches Loss of fragile desert habitat niches Loss of endemic species of flora and faunaLoss of endemic species of flora and fauna

OverOver--optimistic estimates of land’s optimistic estimates of land’s carrying capacitycarrying capacity

OverOver--investment/risky investmentinvestment/risky investment

Pros: long termPros: long term

Cons: long termCons: long term

Water depletionWater depletionGround water resourcesGround water resourcesReservoirsReservoirs

Ogallala aquifer (Ogallala aquifer (Geographical, Geographical, 2000)2000)River systemsRiver systems

Colorado River feeds all of Las Vegas and much of Los Colorado River feeds all of Las Vegas and much of Los AngelesAngeles

Forced migration/ environmental refugeesForced migration/ environmental refugeesLoss of arable landLoss of arable land-->famine, unemployment>famine, unemployment

“Dust Bowl” and Depression“Dust Bowl” and Depression

Cons: Long termCons: Long term

Dust stormsDust stormsChinese dust choking parts of Asia, traveling Chinese dust choking parts of Asia, traveling around the globearound the globe

Loss of topsoilLoss of topsoilIncreased salinity of soilsIncreased salinity of soils

Wasteful water usageWasteful water usageImproper irrigationImproper irrigation

Loss of potable waterLoss of potable water

Combating the SandsCombating the Sands

Tree planting (China has world’s largest program).Tree planting (China has world’s largest program).Wind breaksWind breaksPrevent erosion, trap airborne dirtPrevent erosion, trap airborne dirt

No till/low till farmingNo till/low till farmingLess soil disturbanceLess soil disturbance

Alternative energy (to relieve Alternative energy (to relieve fuelwoodfuelwood pressure).pressure).Solar cookers for foodSolar cookers for foodWind turbines yield energy and wind breaksWind turbines yield energy and wind breaks

Livestock management Livestock management NonNon--tramplingtramplingFeed cut forage in an enclosureFeed cut forage in an enclosure

Combating the SandsCombating the Sands

What is being doneWhat is being doneCameroon: National awareness daysCameroon: National awareness daysEthiopia: National workshop and student tree Ethiopia: National workshop and student tree planting campaignplanting campaignArgentina, Bolivia, Brazil: Organizing National Argentina, Bolivia, Brazil: Organizing National programs to combat desertificationprograms to combat desertificationIsrael: developing orchards and irrigating them with Israel: developing orchards and irrigating them with treated waste water treated waste water (UN Chronicle, 1997)(UN Chronicle, 1997)Africa: “TreeAfrica: “Tree--Aid” local help programs to replant Aid” local help programs to replant vegetation and encourage improved agricultural vegetation and encourage improved agricultural practices. (Navarro, 2001)practices. (Navarro, 2001)

SummarySummary

Desertification is a growing worldwide problem Desertification is a growing worldwide problem that impacts a huge percentage of the world’s that impacts a huge percentage of the world’s population.population.The economic cost of desertification is in the The economic cost of desertification is in the many hundreds of billions of dollars.many hundreds of billions of dollars.Desertification can be slowed and even Desertification can be slowed and even reversed by rereversed by re--vegetation, water conservation, vegetation, water conservation, livestock management and wise agricultural livestock management and wise agricultural methods.methods.

The EndThe End

BibliographyBibliography

Ayres, Ed. Ayres, Ed. World Watch.World Watch. JulyJuly--August, 2003 v16 i4 p.10August, 2003 v16 i4 p.10Cullet, Cullet, PhillipePhillipe, “Desertification.” , “Desertification.” Encyclopedia of Life Encyclopedia of Life Support Support

SystemsSystemsEden Foundation. March 2004. DesertificationEden Foundation. March 2004. Desertification--A Threat to the A Threat to the

SahelSahel. . http://www.edenhttp://www.eden--foundation.org/project/desertif.htmlfoundation.org/project/desertif.htmlEdwards, Chris. Edwards, Chris. Geographical. Geographical. February 2005 v77 i2 February 2005 v77 i2 p.46p.46Collins, Jocelyn. The University of Western Cape Publication. Collins, Jocelyn. The University of Western Cape Publication.

February 2001. February 2001. http://www.botany.uwc.ac.za/Envfacts/factshttp://www.botany.uwc.ac.za/Envfacts/facts//desertification.htmdesertification.htm

Larson, Janet. Larson, Janet. The HumanistThe Humanist. July. July--August 2003 v63 i4 p.39August 2003 v63 i4 p.39Navarro, Jose. “The Taming of the Dunes.” Navarro, Jose. “The Taming of the Dunes.” Geographical. Geographical. Sept. Sept.

2001, v73 i9 p.562001, v73 i9 p.56“Shifting Sands.” “Shifting Sands.” GeographicalGeographical. April 2000 v72 i4 p.24. April 2000 v72 i4 p.24SkouriSkouri, Mohamed. “The Menace of Desert Advance.”, Mohamed. “The Menace of Desert Advance.” UNESCOUNESCO

Courier.Courier. January, 1985, p12January, 1985, p12“Some Good News” “Some Good News” The EcologistThe Ecologist. December 2000 v30 i9 p14. December 2000 v30 i9 p14UN ChronicleUN Chronicle. “What’s being done.” Summer 1997, v34 n2 p29. “What’s being done.” Summer 1997, v34 n2 p29