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1、ClimatechangeintheArcticBeatingaretreatArcticseaiceismeltingfarfasterthanclimatemodelspredict.WhySep24th2011ONSEPTEMBER9thattheheightofitssummertimeshrinkageicecovered4.33msquarekm1.67msquaremilesoftheArcticOceanaccdingt

2、oAmerica’sNationalSnowIceDataCentre(NSIDC).Thatisnotarecdlow—notquite.Buttheactualrecd4.17msquarekmin2007wastheproductofanunusualcombinationofsunnydayscloudlessskieswarmcurrentsflowingupfromlatitudes.Thisyearhasseennosuc

3、hoppositeofaperfectstmyetthesummerseaiceminimumisamere4%biggerthanthatrecd.Addinthefactthatthethicknessoftheicewhichismuchhardertomeasureisestimatedtohavefallenbyhalfsince1979whensatelliterecdsbeganthereisprobablylessice

4、floatingontheArcticOceannowthanatanytimesinceaparticularlywarmperiod8000yearsagosoonafterthelasticeage.ThatArcticseaiceisdisappearinghasbeenknownfdecades.Theunderlyingcauseisbelievedbyallbutahfulofclimatologiststobegloba

5、lwarmingbroughtaboutbygreenhousegasemissions.Yettheratetheiceisvanishingconfoundstheseclimatologists’models.ThesepredictthatifthelevelofcarbondioxidemethanesoonintheatmospherecontinuestorisethentheArcticOceanwillbefreeof

6、floatingsummericebytheendofthecentury.Atcurrentratesofshrinkagebycontrastthislookslikelytohappensometimebetween20202050.ThereasonisthatArcticairiswarmingtwiceasfastastheatmosphereasawhole.Someofthecausesofthisareundersto

7、odbutsomearenot.Thedarknessoflwatercomparedwiththereflectivenessofsnowicemeansthatwhenthelattermelttorevealthefmertheareaexposedabsbsbenefits(sootisbadfpeople’slungs)wouldnotrequirethewholesalerejiggingofenergyproduction

8、whichreducingCO2emissionsimplies.Noteveryoneagreesitwouldwkthough.GunnarMyhreoftheCentrefInternationalClimateEnvironmentalResearchinOslofexamplenotesthattheamountofblackcarbonintheArcticissmallhasbeenfallinginrecentdecad

9、es.Hedoesnotbelieveitisthemissingfactinthemodels.Carbondioxideinhisviewisthemainculprit(crimnal).BlackcarbondepositedontheArcticsnowicehesayswillhaveonlyaminimaleffectonitsreflectivity.TherapidmeltingoftheArcticseaicethe

10、nilluminatesthedifficultyofmodellingtheclimate—butnotinawaythatbringsmuchcomfttothosewhohopethatfearsaboutthefutureclimatemightproveexaggerated.Whenrealityischangingfasterthantheysuggestsitshouldacertainamountofnervousne

11、ssisareasonableresponse.It’sanillwind…ThedirectconsequencesofchangesintheArcticaremixed.TheyshouldnotbringmuchriseinthesealevelsincefloatingiceobeysArchimedes’sprincipledisplacesitsownmassofwater.Adarker—someheatabsbent—

12、ArcticthoughwillsurelyaccelerateglobalwarmingmaythusencouragemeltingofthelboundGreenlicesheet.Thatcertainlywouldraisesealevels(thoughnotasquicklyasNewsCpation’scartographerssuggestinthelatesteditionofthebestselling“Times

13、Atlas”whichclaimsthat15%oftheGreenlsheethasmeltedinthepast12yearsthetruefigureismelike0.05%).Wildlifewillalsosuffer.Polarbearswhichhuntfsealsalongtheice’sedgewalruseswhichfishtherewillbothbehardhit.Theeffectsonthewidercl

14、imatearetrickytoassess.SomemeteologistssuspectunseasonalsnowstmsofftheeastcoastofAmericain2010werepartlycausedbyArcticwarmingshiftingwindpatterns.OnefeedbackloopthatdoesseemscertainthoughisthatthemeltingArcticwillenablet

15、heextractionofmefossilfuelwithallthatthatimpliesfgreenhousegasemissions.TheArcticisreckonedto(beestimatedto)holdaround15%ofthewld’sundiscoveredoilreserves30%ofthoseofnaturalgas.Henceagrowingpolarenthusiasmamongenergycomp

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