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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