Thereisnodoubt

　　thattheearthisbecomingwarmerandthatitishumanactivitythathascaused

　　thisglobalwarming(这是动名词,改不了从句)ratherthanarandombutnaturalphenomenon.

　　Allscientistssubscribetotheview

　　thattheincreaseintheearth'stemperatureisduetotheburning(这是动名词,改不了从句)of

　　fossilfuelslikecoal,naturalgasandoiltoproduceenergy.Somebyproducts

　　ofthisprocessarecalled"greenhouse"gases,themostimportantone

　　ofwhichiscarbondioxide.DrJaniceFosterexplains:"Thereisanatural

　　phenomenonthatscientistscallthe'greenhouseeffect'.Thisiswhensmall

　　amountsofgasesintheatmosphere,likecarbondioxide,methaneandwater

　　vapour,trapheatfromthesunandthereforewarmtheearth.Withoutthe

　　'greenhouseeffect',theearthwouldbeaboutthirty-threedegreesCelsius

　　coolerthanitis.So,weneedthosegases.Theproblembeginswhenweaddhuge

　　quantitiesofextracarbondioxideintotheatmosphere.Itmeansthatmoreheat

　　energytendstobetrapped（不定式作宾语,不好改从句）intheatmospherecausing（现在分词短语定语=whichcauses）theglobaltemperaturetogoup."

　　Weknowthatthelevelsofcarbon

　　dioxidehaveincreasedgreatlyoverthelast100to150years.Itwasa

　　scientistcalled（过去分词短语：定语从句=whowas）

　　CharlesKeeling,whomadeaccuratemeasurementsoftheamountofcarbondioxide

　　intheatmospherefrom1957to1997.Hefoundthatbetweentheseyearsthe

　　carbondioxideintheatmospherewentupfromaround315partstoaround370

　　partspermillion.

　　Allscientistsacceptthisdate.They

　　alsoagreethatitistheburning(这是动名词：主语,改不了从句)ofmorefossilfuelsthathasresultedinthis

　　increaseincarbondioxide.

　　Sohowhighwillthetemperatureincreasego?DrJaniceFostersaysthatover

　　thenext100yearstheamountofwarming(这是动名词：宾语,改不了从句)couldbeaslowas1to1.5degreeCelsius,but

　　itcouldbeashighas5degrees.

　　Howevery,theattitudeofscientists

　　towardsthisriseiscompletelydifferent.Ontheonehand,DrFosterthinks

　　thatthetrendwhichincreasesthetemperatureby5degreeswouldbea

　　catastrophe.Shesays,"Wecan'tpredicttheclimatewellenoughtoknow（不定式结果状语：=sowellthatweknow）whattoexpect(=whatweshouldexpect)toknow

　　whattoexpect(=whatweshouldexpect),butitcoldbeveryserious."Other

　　whoagreewithherthinktheremaybeariseofseveralmetresinthesea

　　level,orpredictseverestorms,floods,droughts,famines,thespreadofspecies.

　　Ontheotherhand,therearethose,likeGeorgeHambley,whoareopposedto

　　thisview,believethatweshouldnotworryabouthighlevelsofcarbon

　　dioxideintheair.Theypredictthatanywarming(这是动名词：主语,改不了从句)willbemildwithfewbadenvironmental

　　consequences.Infact,Hambleystates,"Morecarbondioxideisactuallya

　　positivething.Itwillmakeplantsgrowquicker;cropswillproducemore;it

　　willencourageagreaterrangeofanimala-allofwhichwillmakelifefor

　　humanbeingsbetter."