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1、ThePlanetEarthThe2000AntarcticOzoneHoleWasLargestEverThe2000AntarcticOzoneHolewasthelargesteverobserved.Earthswetterupperatmospheremaydelayglobalozonerecovery.NASAresearchershavefoundthatanincreaseinwatervaporinthestratosphere,stemmingpartiallyfromgr
2、eenhousegases,maydelayozonerecoveryandincreasetherateofclimatechange.Tocheckonthelong-termstratosphericcoolingandozonedepletion,NASAputdatafromsatellitesandotherremotesensorsintoitsGISSglobalclimatemodel.Itwasthefirststudytolinkgreenhousegasestoincre
3、asedozonedepletionoverpopulatedareas?Waterandozone.Climatemodelsshowcoolerstratospherictemperatureshappenwhenthereismorewatervaporpresent.Watervaporalsoleadstothebreakdownofozonemolecules.Thestratosphereisthedrylayeroftheatmosphereabovethetroposphere
4、,wheretemperaturesincreasewithheight.Accordingtosatellitedata,upperatmospherictemperaturesaroundtheworld-ataltitudesof20to35mileshigh-havecooledbetween5.4and10.8degreesFahrenheitoverrecentdecades.Drivingforces.NASAfoundtwodrivingforcesbehindthechange
5、instratosphericmoisture:Increasedemissionsofthegreenhousegasmethanearetransformedintowaterinthestratosphere,accountingforaboutathirdoftheobservedincreaseinmoisturethere.Morewateristransportedfromtheloweratmosphere?Warmerairholdsmorewatervaporthancold
6、erair,sotheamountofwatervaporintheloweratmosphereincreasesasitiswarmedbythegreenhouseeffect.Greenhousegases,suchascarbondioxideandmethane,mayenhancethetransportofwaterintothestratosphere.Theincreasedtransportofwatervaportothestratosphereseemslikelyto
7、havebeeninducedbyhumanactivities.Ozonedestruction.Risinggreenhousegasemissionsaccountforallorpartofthewatervaporincrease,whichcausesstratosphericozonedestruction.Whenmorewatervaporworksitswayintothestratosphere,thewatermoleculescanbebrokendown,releas
8、ingreactivemoleculesthatcandestroyozone.Ifthetrendofincreasingstratosphericwatervaporcontinues,itcouldincreasefutureglobalwarmingandimpedeozonestratosphericrecovery.Theimpactonglobalwarmingcomesaboutbecausebothwatervaporandozonearegreenhousegases,whi
