人类活动的气候影响.ppt

全球气候系统,GlobalClimateSystem,人类活动的气候影响,什么是温室效应地球大气中有哪些温室气体温室气体从何处来温室效应很不好,是吗近百年的气候变化有多少是温室效应造成的如果CO2加倍全球温度会上升多少21世纪气候会怎样不确定性有多大有关全球变暖的争论,地球大气中有哪些温室气体温室气体从何处来,Halocarbonsarecarbon-basedcompoundsthatcontainchlorine,fluorine,bromine,oriodine.TheCFCs,halonsbromine-containingCFCs,hydrofluorocarbonsHFCs,chloroCHCl3andcarbontertrachlorideCCl4areexclusivelyofindustrialoriginanddidnotexistpriorto60yearsago.,Halocarbonsareresponsiblefortheenvironmentalproblemofstratosphericozonedepletionandseveralofthecompoundsarestronggreenhousegases.CFCsarefarlessabundantintheatmospherethanCO2butare10,000timesmorepowerfulasgreenhousegases.ProportionofCFCshasdeclinedsincebanningoftheirusein1984.,AnnualglobalemissionsofthehalocarbonsCFC-11filledblacksquaresandCFC-12opensquarestotheatmospherefrom1972to1992,principallyfromtheiruseasrefrigerantsandagentsfortheblowingoffoam.NoticethedeclineinemissionsfollowingenactmentoftheMontrealProtocolin1987.AfterWorldMeteorologicalOrganization,1994.,ConcentrationsofCarbonDioxide.AtmosphericcarbondioxideconcentrationinpartspermillionppmasrecordedatfivesitesdatafromBradleyandJones,1995.,温室效应很可怕,是吗,,,,近百年的气候变化有多少是温室效应造成的,气候系统对各种强迫的敏感性的不确定性2xCO24W/m21.2Cwithoutfeed-backsactualvalue3C1.5-4.5C,21世纪气候会怎样,,,,是祸还是福何种对策,全球变暖的有关争论,Table1.KeyDifferenceswithSkeptics1.ObservedglobalwarmingrealormeasurementproblemHansenglobalwarmingis0.5-0.75Cinpastcentury,atleast0.3Cinpast25years.Lindzensinceabout1850“...morelikely...0.10.3C“MITTechTalk,34,7,1989.,2.Climatesensitivityequilibriumresponseto2xCO2Lindzen1CHansen31CCommentspaleoclimatedata,improvedclimatemodels,andprocessstudiesmaynarrowuncertainties;observedclimatechangeondecadaltimescaleswillprovideconstraintifclimateforcingsaremeasured;implicitinationonclimatesensitivitycanbeextractedfromobservedchangesinoceanheatstorage.,3.WatervaporfeedbackLindzennegative,uppertroposphericwatervapordecreaseswithglobalwarming.Hansenpositive,upperandlowertroposphericwatervaporincreasewithglobalwarming.ReferencestheseincludereferencesbyLindzenstatingthat,inresponsetoglobalwarming,watervaporwilldecreaseataltitudesabove2-3km.Commentaccurateobservationsofinterannualchangesseveralyearsandlong-termchanges1-2decadesofuppertroposphericwatervaporcouldprovidedefiningdata.,4.CO2contributiontothe33CnaturalgreenhouseeffectLindzen“Evenifallothergreenhousegasessuchascarbondioxideandmethaneweretodisappear,wewouldstillbeleftwithover98percentofthecurrentgreenhouseeffect.“CatoReview,Springissue,87-98,1992;“IfallCO2wereremovedfromtheatmosphere,watervaporandcloudswouldstillprovidealmostallofthepresentgreenhouseeffect.“Res.Explor.9,191-200,1993.LacisandHansenremovingCO2,withwatervaporkeptfixed,wouldcooltheEarth5-10C;removingCO2andtracegaseswithwatervaporallowedtorespondwouldremovemostofthenaturalgreenhouseeffect.,5.WhenwillglobalwarmingandclimatechangebeobviousLindzenIpersonallyfeelthatthelikelihoodoverthenextcentury[21stcentury]ofgreenhousewarmingreachingmagnitudescomparabletonaturalvariabilityremainssmall.Hansen“Withtheclimatologicalprobabilityofahotsummerrepresentedbytwofacessaypaintedredofasix-faceddie,judgingfromourmodelbythe1990sthreeorfourofthesixdiefaceswillbered.Itseemstousthatthisisasufficientloadingofthedicethatitwillbenoticeabletothemaninthestreet.“J.Geophys.Res.93,9341-9364,1988.,6.PlanetarydisequilibriumHansenEarthisoutofradiativeequilibriumwithspacebyatleastapproximately0.5W/m2absorbingmoreenergythanitemits.CommentsThisisthemostfundamentalmeasureofthestateofthegreenhouseeffect.Becausethedisequilibriumisaproductofthelongresponsetimeoftheclimatesystem,whichinturnisastrongfunctionofclimatesensitivity,confirmationofthedisequilibriumprovidesinationonclimatesensitivityandanindicationofhowmuchadditionalglobalwarmingis“inthepipeline“duetogasesalreadyaddedtotheatmosphere.,Thisdisequilibriumcouldbemeasuredasthesumoftherateofheatstorageintheoceanplusthenetenergygoingintothemeltingofice.Existingtechnology,includingveryprecisemeasurementsofoceanandicesheettopography,couldprovidethisination.,1气候与气候变化2气候灾害风险3两个例子4气候灾害风险管理5气候变化风险指标,DelworthKnutson,2000,DelworthKnutson,2000,