大学英语听力教程第三册（第二版）听力原文UNIT1IstheEarthBeingSqueezedDryPart1GettingreadySectionB1.TheAmazonforestsaredisappearingbecauseofincreasedburningandtreeremoval.InSeptember,satellitepicturesshowedmorethan20000firesburningintheAmazon.Expertssaymostofthesefiresweresetbyfarmers.Thefarmerswereattemptingtoclearlandtogrowcrops.TheWorldWildlifeFundsaysanotherseriousproblemisthattoomanytreesintheAmazonrainforestarebeingcutdown.TheWorldWildlifeFundsaysthefiresshowtheneedforurgentinternationalactiontoprotecttheworld'srainforests.Thegroupwarnsthatwithoutsuchactionsomeforestscouldbelostforever.2.EnvironmentalissuesswelltothefullinBerlinthisweek,fortheUNsponsoredconferenceonglobalwarmingandclimatechangeisthefirstsuchmeetingsincetheRiosummitthreeyearsago.WithscientistsandgovernmentsnowgenerallyreadytoacceptthattheearthclimateisbeingaffectedbyemissionsofCO2andothergreenhousegases,overahundredcountriesaresendingdelegations.ButhowmuchprogresshasbeenmadeimplementingthegreenhousegasreductiontargetagreedonatRio?SimonDaryreports.Part2TheEarthatrisk(1)I:BrianCowlesistheproducerofanewseriesofdocumentariescalled"TheEarthatRisk"whichcanbeseenonChannel4laterthismonth.Eachprogramdealswithadifferentcontinent,doesn'tit,Brian?B:That'sright.WewenttoAmerica,bothNorthandSouthandthenwewentovertoAfricaandSouth-EastAsia.I:Andwhatdidyoufindineachofthesecontinents?B:StartingwithAfrica,ourfilmshowstheimpactofthepopulationontheenvironment.Generallyspeaking,thishascausedtheSaharaDeserttoexpand.It'sabitofaviciouscirclewefind.Peoplecutdowntreesforfirewoodandtheirdomesticanimalseatalltheavailableplants—andsoconsequentlytheyhavetomovesouthastheSaharaDesertexpandsfurthersouth.Imean,soonthewholeofMaliwillbecomeadesert.AndinEastAfrica:herethegrasslandsaresupportingtoomanyanimalsandtheresultis,ofcourse,there'snograss—nothingfortheanimalstoeat.I:Isee.AndthenextfilmdealswithNorthAmerica?B:That'sright.IntheUSA,asyouknow,intensiveagriculturerequiresaplentifulsupplyofrainforthesecropstogrow;Imeanifthereisn'tenoughrainthecropsdon'tgrow.Andgrowingcropsstabilizesoil,withoutthemthetopsoiljustblowsaway.Thisisalsotrueforanyregionthatisintenselyfarmed—mostofEurope,forexample.I:AndwhatdidyoufindinSouthAmerica?B:InSouthAmerica(asinCentralAfricaandSouthernAsia)tropicalforestsarebeingcutdownatanalarmingrate.ThisisdonesothatpeoplecansupportthemselvesbygrowingfoodortocreaterancheswherecattlecanberaisedtobeexportedtoEuropeorAmericaastinnedmeat.Theproblemisthatthesoilissopoorthatonlyacoupleofharvestsarepossiblebeforethisverythinsoilbecomesexhausted.Anditcan'tbefedwithfertilizerslikeagriculturallandinEurope.Forexample,inBrazilin1982anareaofjunglethesizeofBritainandFrancecombinedwasdestroyedtomakewayforanironoremine.HugenumbersoftreesarebeingcutdownforexportsashardwoodtoJapan,Europe,USAtomakethingslikeluxuryfurniture.Theseforestscan'tbereplaced—theforestsoilisthinandunproductiveandinjustafewyears,ajunglehasbecomeawasteland.Tropicalforestscontainrareplants(whichwecanuseformedicines,forexample)andanimals—oneanimalorplantspeciesbecomesextincteveryhalfhour.Theseforesttreesalsohaveworldwideeffects.Youknow,theyconvertcarbondioxideintooxygen.Theconsequenceofdestroyingforestsisnotonlythattheclimateofthatregionchanges(becausethereislessrainfall)butthischangeaffectsthewholeworld.Imean,overhalftheworld'srainforesthasbeencutdownthiscentur...
