environmental-protection(环境保护演讲ppt)

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1、TeamfromlandscapearchitectureclassXTeamMembers：EnvironmentalProtectionOurtopicWhatdoyouknowaboutgreenhouseeffect?Globalwarming?Risingsealevels?Theimpactontheearth?OutlineGreenhouseeffectGlobalwarmingRisingsealevelsGreenhouseeffectWhatisthegreenhouseeffect?Onasunnywinterday,youparkyourcarinthes

2、un,lockit,andgocruisethelocalshoppingmallforacoupleofhours.Whenyoucomebacklaterandgetintoyourcar,whatdoyounotice?Istheinteriorofthecarhotorcold?Howdoesthetemperatureinsideofyourcarcomparetothetemperatureoutside?Ifyouhaveeverbeeninsideofagreenhouse,especiallywhenthesunisout,whathaveyouobserved?

3、Itisdefinitelywarm,andusuallytheairismoist.Agreenhouseiscommonlywarmerthantheoutsideairbecauseagreenhousehastheabilitytotrapheatinsideofit.Thisphenomenoniscalledthegreenhouseeffect.GreenhouseeffectTheheatcausedbyinfraredradiationisabsorbedby"greenhousegases"suchaswatervapor,carbondioxide,ozone

4、andmethane,whichslowsitsescapefromtheatmosphere.Althoughgreenhousegasesmakeuponlyabout1percentoftheEarth'satmosphere,theyregulateourclimatebytrappingheatandholdingitinakindofwarm-airblanketthatsurroundstheplanet.Lifeontheearthdependsonenergyfromthesun.About30percentofthesunlightthatbeamstoward

5、Earthisdeflectedbytheouteratmosphereandscatteredbackintospace.Therestreachestheplanet'ssurfaceandisreflectedupwardagainasatypeofslow-movingenergycalledinfraredradiation.GreenhouseeffectThegreenhouseeffectisanaturallyoccurringprocessthataidsinheatingtheEarth'ssurfaceandatmosphere.Itresultsfromt

6、hefactthatcertainatmosphericgases,suchascarbondioxide,watervapor,andmethane,areabletochangetheenergybalanceoftheplanetbyabsorbinglongwaveradiationemittedfromtheEarth'ssurface.WithoutthegreenhouseeffectlifeonthisplanetwouldprobablynotexistastheaveragetemperatureoftheEarthwouldbeachilly-18°Celsi

7、us,ratherthanthepresent15°CelsiusGreenhouseeffectHowDoHumansContributetotheGreenhouseEffect?WhilethegreenhouseeffectisanessentialenvironmentalprerequisiteforlifeonEarth,therereallycanbetoomuchofagoodthing.Theproblemsbeginwhenhumanactivi