UnitFour:

TheGreenhouseEffect第四課溫室效應(yīng)1第一頁，共39頁。Newwords:Triple三倍于quadruple四倍于NationalAcademyofScience國家科學(xué)院Impact影響effectFeedback反響annual每年的Seasonal每季的Expand擴展extendspreadAntarctic南極洲Greenland格陵蘭Flood洪水泛濫Bangladesh孟加拉BayofBengal孟加拉灣(BOB)Timely定時的，及時的Zone區(qū)域region2第二頁，共39頁。Infraredradiation紅外輻射Climaticfeedback氣候反響Snowcover雪蓋Etal.等等〔人〕etc.等等〔物〕

3第三頁，共39頁。4第四頁，共39頁。5第五頁，共39頁。6第六頁，共39頁。7第七頁，共39頁。輻射物體以電磁波或粒子流形式向周圍傳遞或交換能量的方式。電磁波譜輻射的根本知識輻射是太陽能傳輸?shù)降厍虻奈ㄒ煌緩?第八頁，共39頁。大氣窗:7~139第九頁，共39頁。大氣中的輻射傳輸過程大氣對短波的影響吸收散射反射吸收逆輻射大氣對長波的影響10第十頁，共39頁。11第十一頁，共39頁。12第十二頁，共39頁。13第十三頁，共39頁。ppm:partpermillion14第十四頁，共39頁。15第十五頁，共39頁。P1:①Manisreversingmillionsofyearsofnaturalevolutionbyputtingintotheatmospherecarbonthathadbeensequesteredovertheagesasfossilfuels.②AtmosphericconcentrationsofCO2arelikelytodouble,andpossiblytriple,by2100.③Becausenohistoricalprecedentexists,reasonableexpectationsaboutfutureclimatemustbebasedonscientificevidence,notgeologicalrecords.④Afterevaluatingtheavailableevidence,theNationalAcademyofSciencesconcludedthatadoublingofatmosphericconcentrationsofCO2wouldwarmtheearth’saveragetemperature1.5-4.5℃.16第十六頁，共39頁。17第十七頁，共39頁。P2:①Thegreenhouseeffectoftheatmospherehasneverbeendoubted.②Moreofthesun’sradiationisvisiblelight,whichpassesthroughtheatmospherelargelyundeterred.③Whentheradiationstrikestheearth,itwarmsthesurface,whichthenradiatestheheatasinfraredradiation.However,atmosphericCO2,watervapor,andsomeothergasesabsorbtheinfraredradiationratherthanallowittopassundeterredlythroughtheatmospheretospace.④Becausetheatmospheretrapstheheatandwarmstheearthinamannersomewhatanalogoustotheglasspanelsofagreenhouse,thisphenomenonisgenerallyknownasthe“greenhouseeffect〞.Withoutthiseffect,theearthwouldbe33℃(60℉)colderthatitiscurrently.18第十八頁，共39頁。P3:①TheextenttowhichCO2absorbsheathasbeenknownforalmostacentury,ScientistsshowthatdoublingofatmosphericCO2wouldraisetheaveragetemperature1.2℃ifnothingelseintheearth’sclimaticsystemchanged.②However,manypartsoftheclimatewillchange,amplifyingthedirectimpactofCO2.③Becausethesechangesarenotcompletelyunderstood,thetotalwarmingisdifficulttoestimate.④ThecurrentuncertaintysurroundingtheimpactofCO2onaveragetemperatureiscenteredaroundtheseclimatic“feedback〞,notthedirectwarmingfromCO2.19第十九頁，共39頁。P4：①Themostimportantfeedbackwillresultfromthewarmeratmosphere’sabilitytoretainmoisture.②Becausewatervaporalsoabsorbsinfraredradiation,additionalheatingwillresult.③Hansoneral.estimatethatdoubleCO2℃.20第二十頁，共39頁。P5:①Anotherimportantpositivefeedbackconcernstheimpactofsnowandicecoverontheearth’salbedo,theextenttowhichitreflectssunlight.②Iceandsnowreflectmostofthesun’sradiation,whilewaterandsoilabsorbit.③Anincreaseinsurfacetemperatureswouldmeltsnowonlandandfloatingiceandtherebyallowtheearthtoabsorbenergythatwouldotherwisebereflectedbackintospace.④Hansonetal.estimateanadditionalwarmingof0.4℃fromthealbedoeffect.21第二十一頁，共39頁?！妗?℃fromclouds.22第二十二頁，共39頁。P7：①AlthoughtheincreaseintheaveragetemperatureoftheearthisaconvenientshorthanddescriptionofCO2inducedclimatechange,itmasksimportantregionalimplications.②Mostsearchersagreethatpolartemperaturewouldincreasetwotothreetimestheearth’saverageincrease.③Theworld’sclimatedependslargelyoncirculationpatternsbywhichtheatmosphereandtheoceanstransportheatfromwarmtocoldregions.23第二十三頁，共39頁。P7：④Asaresult,anysignificantchangeinthedifferencebetweenequatorialandpolartemperaturescoulddramaticallyaffectclimaticpatterns.⑤Aparticularlyimportanteffectofthesechangeswillbeshiftsinannualandseasonalprecipitationandevaporation,withsomeareasgainingandotherlosing.⑥Furthermore,becausehurricanesrequireanoceantemperatureof27℃orwarmer,aglobalwarmingcouldallowhurricanestoformathigherlatitudesandduringagreaterpartoftheyear.⑦Thesechangescouldbeimportanttocoastalcommunities.24第二十四頁，共39頁。P8：①Amoreimmediate(直接的〕concernisthattheprojectedglobalwarmingcouldraisetheseaasmuchasonemeterinthenextcenturybyheatingoceanwater,whichwouldthenexpand,andbycausingmountainglaciersandpartsoficesheetsinWestAntarctica,EastAntarctica,andGreenlandtomeltorslideintotheoceans.②Thus,theseacouldreachheightsunprecedentedinthehistoryofcivilizationuntilthiseffort.③Noonehadattemptedtoforecastsealevelriseinspecificyearsordetermineitsimportancetotoday’sactivities.25第二十五頁，共39頁。P9:①Ifthispredictioncomestrue,thewaterwillfloodover15percentifBangladesh’sterritory,about12to15percentofEgypt’scultivatedlandandsignificantlyreducetheterritoryofmanyislandcountries.②IntheUnitedStates,thousandsofsquaremilesoflandcouldbelost,particularlyinlow-lyingareassuchastheMississippiDelta,wherethelandisalsosubsidingatapproximatelyonemeterpercentury.③Stormdamage,alreadyestimatedatoverthreebilliondollarsperyearnationwide,couldalsoincreasethesalinityofmarshes,estuaries,andaquifers,disruptingmarinelifeandpossiblythreateningsomedrinkingwatersupplies.26第二十六頁，共39頁。④Thegreenhousegasesarealsodamagingtheozonelayersurroundingtheearthwhichprotectshumanbeingsfromultravioletradiation.⑤Researchshowsthatcancercouldincreaseby3percentforevery1percentreductionintheozonelayer.⑥Fortunately,themostadverse(不利的〕effectscanbeavoidediftimelyactionsaretaken.27第二十七頁，共39頁。P10：AlthoughtheclimaticchangesthatcouldresultfromCO2emissionsispoorlyunderstood,thereiscompleteagreementthatCO2concentrationsareincreasing.28第二十八頁，共39頁。P11：①Approximatelyone-halftheCO2releasedbycombustionoffossilfuelshasremainedintheatmosphere.②ItisgenerallybelievedthatmostoftheremainingCO2hasdissolvedintotheoceans.③AlthoughtropicaldeforestationandcementproductionalsoresultinCO2emission,theircontributionhavebeenandwillcontinuetobemuchlessimportant.29第二十九頁，共39頁。P12：①Controllingthegreenhousegases,especiallytheincreasingdischarge〔排放〕ofcarbondioxidehasalreadybecomeakeyproblem.②Theglobalcommunitymustmakeeffortstoreducethegreenhouseeffect.30第三十頁，共39頁。P13：①Inthenextfewdecades,however,CO2emissionsareunlikelytobecurtailed,eithervoluntarilyorbyregulation.②Theworld’sinfrastructureisbuiltaroundfossilfuels.③Thecost〔本錢〕ofusingcoal,gasandoilislowcomparedwithnuclearandsolarpower,andthisrelativecostadvantage〔優(yōu)勢〕isexpectedtocontinue.④Therefore,avoluntaryreductioninCO2emissionsisunlikely.31第三十一頁，共39頁。P14：①TheonlygovernmentactionthatcouldsuccessfullyreduceCO2emissionswouldbetocurtailtheuseoffossilfuels.②EmissioncontrolsforCO2frompowerplants〔電廠〕wouldatleastquadruplethecostofelectricity.③Forsmallerusersoffossilfuels,suchashomesandmotorvehicles,controlisnotevenfeasible.④Otherplans,suchassequesteringcarboninmassivetreeplantings,areevenlessplausible.32第三十二頁，共39頁。P15：①Evenifpoliticalleadersdecidetotakedrastic〔嚴厲的〕actionstolimitworldwideconsumptionoffossilfuels,itisprobablyalreadytoolatetopreventsignificantrisesinglobaltemperaturesandsealevel.②Arecentstudyinvestigatedtheimpactofdrasticenergypolicychangesontheexpectedtimingofagreenhousewarming(SeidelandKeyes,1983).③Theauthorsconcludedthatsuchpoliciescouldhaveimportantimpactby2100,butwouldnotsubstantiallydelaythe2°Cwarmingexpectedby2040.33第三十三頁，共39頁。④Theyestimatedthata300percenttaxonfossilfuelswoulddelaythe2Cwarmingbyonlyfiveyears,andthatevenaworldwidebanoncoal,shale〔頁巖〕oil,andsyntheticfuelswoulddelaythewarmingbyonlytwenty-fiveyears,ifimplementedby2000.⑤Furthermore,suchabanwoulddelaytheriseinsealevelexpectedthrough2040byonlytwelveyears.34第三十四頁，共39頁。P16：①Thepoliticalfeasibilityofinstituting〔制定〕suchabanby2000isalsodoubtful,becauseonlyaworldwideagreementtocurtailemissioncouldbesuccessful.②AnyindividualnationthatcurtailsitsownemissionswilldelaythedaywhenCO2concentrationsdoublebyafewyearsatmost.③Furthermore,becauseenergycostswouldincreaseforanynationthatcurtailsitsemissions,thatnation’sindustrieswouldbeplacedatacompetitivedisadvantagecomparedwiththoseoftherestoftheworld.35第三十五頁，共39頁。④Finally,politicalleaderswouldrequireproofthatsuchapolicywouldbemorebeneficialthanadaptingtohigherCO2levels.⑤Suchproofwillprobablyremainimpossibletoprovidefortheforeseeablefuture.36第三十六頁，共39頁。P17：①Theimpactofincreasingconcen