Geography Y1 (Y2 for Nanyang [nanyang 2024 EOY syllabus])

Deforestationisthepurposefulclearingofforestbyhumansleadingtothedecreaseofforestareasintheworld. Forestsareimportantbecausethey:1. Managequantityandqualityofwatersupply2. Theyreplenishatmosphericoxygenandremovecarbondioxidefromtheatmosphere3. Theymaintainnutrientsinthesoil4. Theyareahabitatforfloraandfauna5. Theyareahabitforpeople6. Theyprovideasourceforusefulmaterialsliketimbreandoilpalm ThecausesofDeforestationare:1. Agriculture2. Logging3. Constructionofinfrastructure4. Urbanisation5. Climatechange Theimpactsofdeforestationsare:1. Environmentalimpact:a. Lossofbiodiversityb. Lossofwatercatchmentareasc. Enhancedgreenhouseeectd. Increasedriskofflooding,soilerosion,andsedimentation2. Economicimpact:a. Depletionofnaturalresources3. Socialimpact:a. Lossofhabitatsofindigenouspeople Impacts:forestfiresandhaze- Deforestation,thelarge-scaledeforestation,primarilyforpalmoilplantations,timberextractions,andotheragriculturalactivities,isamajorcauseofforestfires.Forestsareoftenclearedbycuttingandburningvegetation,whichcanleadtouncontrolledfiresthatcaneasilyspreadtosurroundingareas,especiallyduringthedryseason.SinceKalimantanhasextensivepeatlands,whicharecarbon-richandhighlyflammablewhendrainedanddriedforagriculture,firesinpeatlandsareverydiculttoextinguish

andcansmoulderundergroundforlongperiods,releasinglargeamountsofsmokeandcarbondioxide.- Thesefirescanleadtoincreasedhazelevels.Theairqualityindex(AQI)andlevelsofparticulatematter(PM2.5)oftenreachhazardouslevelsduringfireseasons.In2015,PM2.5levelsinsomeareasofKalimantanexceeded1000microgramspercubicmetre,farabovetheworldhealthorganisation’sguidelineof25microgramspercubicmetrefora24-hourperiod.Prolongedexposuretohazecanleadtoincreasedhospitaladmissionsandprematuredeaths.Vulnerablepopulations,suchaschildren,theelderly,andthosewithpre-existinghealthconditions,areatgreaterrisk.- TheIndonesiangovernmenthasimplementedvariouspoliciestoreducedeforestationandpreventfires,includingamoratoriumonnewpalmoilplantationsandeortstorestoredegradedpeatlands. Impact:soilerosion,sedimentation,andflooding- SoilErosionleadstothelossofthetopsoil,whichisthemostfertilelayer.Thisreducessoilfertilityandagriculturalproductivity.- Landslidesalsooccurinhillyormountainousareas,severeerosioncanleadtolandslides,whicharehazardoustohumansettlementsandinfrastructure.DeforestedareasinKalimantancanexperiencesoilerosionratesofupto90tonsperhectareperyear.- InPeatlandareas,deforestationcanleadtothedegradationofpeat,cursingsubsidenceandfurthererosion.Peatlands,whendrainedanddeforested,canerodeatarateofupto20cmperyear.- Sedimentationcausesriverstosiltup,reducingtheircapacitytocarrywater.Thiscanleadtomorefrequentandsevereflooding.- Highlevelsofsedimentsinwaterbodiesdegradewaterquality,aectingaquaticlifeandmakingthewaterunsuitableforhumanconsumptionandotheruses.Forexample,thebarrioriver,oneofthemajorriversinKalimantan,hasseensedimentationratesincreasebymorethanthreefoldoverthepastfewdecades.- Inheavilydeforestedwatersheds,sedimentyieldscanreachover500tonspersquar