英语高级视听听力原文Unit5Theglobalwarning

1、10/10v1.0可编写可更正Unit5TheglobalwarningTheNorthPolehasbeenfrozenfor100,000years.Butaccordingtoscientists,thatwontbetruebytheendofthiscentury.Thetopoftheworldismelting.Theresbeenadebateburningforyearsaboutthecausesofglobalwarming.Butthescientistsyoureabouttomeetsaythedebateisover.Newevidenceshowsmanisco

2、ntributingtothewarmingoftheplanet,pumpingoutgreenhousegasesthattrapsolarheat.MuchofthisnewevidencewascompiledbyAmericanscientistBobCorell,wholedastudycalledtheArcticClimateImpactAssessment.Itsanawkwardnamebutconsiderthefindings:theseasarerising,hurricaneswillbemorepowerful,likeKatrina,andpolarbearsm

3、aybeheadedtowardextinction.WhatdoesthemeltingarcticlooklikeCorrespondentScottPelleywentnorthtoseewhatBobCorellcallsaglobalwarning.Towersoficetheheightof10-storybuildingsriseonthecoastofGreenland.ItsthebiggesticesheetintheNorthernHemisphere,measuringsome700,000squaremiles.Buttemperaturesinthearcticar

4、erisingtwiceasfastastherestoftheworld,soalotofGreenlandsiceisrunningtothesea.Rightnowtheentireplanetisoutofbalance,saysBobCorell,whoisamongtheworldstopauthoritiesonclimatechange.Heled300scientistsfromeightnationsintheArcticClimateImpactAssessment.1v1.0可编写可更正Corellbelieveshehasseenthefuture.Thisisabe

5、llwether,abarometer.Somepeoplecallitthecanaryinthemine.Thewarningthatthingsarecoming,hesays.In10yearshereinthearctic,weseewhattherestoftheplanetwillseein25or35yearsfromnow.Overthelastfewdecades,theNorthPolehasbeendramaticallyreducedinsizeandCorellsaystheglacierstherehavebeenrecedingforthelast50years

6、.Backin1987,PresidentReaganaskedCorelltolookintoclimatechange.Hesbeenatiteversince.InIceland,heshowed60Minutesglaciersthatweregrowinguntilthe1990sandarenowmelting.Infact,98percentoftheworldsmountainglaciersaremelting.Corellsaysallthatwaterwillpushsealevelsthreefeethigherallaroundtheworldin100years.Y

7、ouandIsithere,anotherfoot.Yourchildren,anotherfoot.Yourgrandchildren,anotherfoot.Anditwonttakelongforsealeveltoinundate,saysCorell.Sealevelwillbeinundatingthelowlandsofvirtuallyeverycountryoftheworld,oursincluded,Corellpredicts.Tofindthesightsandsoundsofthearcticmelting,therearefewplacesbetter2v1.0可

8、编写可更正thanafjordinGreenland,withaglacierjustashortdistanceaway.Pelleystoodonahugeblockoficethathadsplitofffromtheglacierandhaddroppedintotheseaabigiceberg.ThispartofGreenlandismeltingfasterthanjustaboutanyother.Togetasenseoftheenormityofwhatshappening,considerthis:Theicethatismeltinghereistheequivale

9、ntofalltheiceintheAlps,Pelleyexplained,standingatoptheiceberg.Thatsmorethan105millionacresofmeltedicein15years.JustfourminutesafterPelleyclearedoffthisberg,partoftheicecavedin.60Minutesgotabirds-eyeviewofhowunstabletheiceisbecomingonaflightwithglaciologistCarlBoggild.Boggildanchored10researchstation

10、stotheice.Buteverytimehecomestovisit,theiceandhisstationshavemoved.Flyingovertheice,Pelleynoticedlotsoffissuresandcrevicesbreakingthroughtheice.Askedwhatcausesthis,Boggildexplained,Thisisactuallytheiceflow,whereyouhavesomuchtensionintheicethatitcannotsticktogether.Anditbreaksandopensacrevicewhichgoe

11、sabout150,200feetdown.Theiceisalsomeltingonthesides,Boggildsays.3v1.0可编写可更正Highoverhead,Pelleyremarkedthatonecouldhearthewaterrunning.Itslikeasmallriver,Boggildsaid.Aleadingtheorysaysthoselittleriverslubricatethebottomoftheicesheet,helpingitmoveoffthebedrockandouttosea.Andtheremaybenostoppingit.Arct

12、icwarmingisaccelerating.Itsachainreaction.Assnowandicemelttheyrevealdarklandandwaterthatabsorbsolarheat.Thatmeltsmoresnowandice,andarounditgoes.Thereslongbeenadebateabouthowmuchofthisisearthsnaturallychangingclimateandhowmuchismansdoing.PaulMayewski,attheUniversityofMaine,saystheanswertothatquestion

13、isfrozeninsideanicecorefromGreenland.WithfundingfromtheNationalScienceFoundation,Mayewskihasled35expeditionscollectingdeepicecoresfromglaciers.Theicecaptureseverythingintheair,layingdownarecordcoveringhalfamillionyears.Wecangotoanysectionoftheicecore,totell,basically,whatthegreenhousegaslevelswere;w

14、ecantellwhetherornotitwasstormy,whatthetemperatureswerelike,Mayewskiexplains.60MinutesbroughtMayewskibacktoGreenland,wherehesayshisresearchhasproventhattheiceandtheatmospherehavemansfingerprintsalloverthem.Mayewskisayswehaventseenatemperaturerisetothislevelgoingbackat4v1.0可编写可更正least2,000years,andar

15、guablyseveralthousandyears.Asforcarbondioxide(CO2)levels,Mayewskisays,wehaventseenCO2levelslikethisinhundredsofthousandsofyears,ifnotmillionsofyears.Whatdoesthattellhim？Itallpointstosomethingthathaschangedandsomethingthathasimpactedthesystemwhichwasntdoingitmorethan100yearsago.Andweknowexactlywhatit

16、is.Itshumanactivity,hesays.Itsactivitylikeburningfossilfuels,releasingcarbondioxideandothergreenhousegases.TheU.S.isbyfarthelargestpolluter.Corellsaystheressomuchgreenhousegasintheairalreadythatmoretemperatureriseisinevitable.Evenifwestoppedusingeverycar,truck,andpowerplantstoppingallgreenhousegasem

17、issionsMayewskisaystheplanetwouldcontinuetowarmanyway.Wouldcontinuetowarmforanother,aboutanotherdegree,hesays.ThatsenoughtomelttheArcticandifgreenhousegasescontinuetoincrease,thetemperaturewillriseevenmore.Theicethatsmeltingalreadyischangingtheweatherbydisruptingoceancurrents.Corellpointstofloodsint

18、heU.S.,heatwavesinEurope;and60Minuteswantedtoknowaboutthecatastrophic2005hurricaneseason.TheonethingIthinkwecansaywithafairlyhighdegreeofconfidenceis5v1.0可编写可更正theseverityofthestorms,howstrongthestorms,thesecycloniceventslikehurricanesandcyclonesinthePacific,aregoingtogettheyregonnabemoresevere.Nowo

19、nethingthatisindoubtiswhethertherellbemoreofthem,Corellexplains.TheoceansoftheNorthernHemispherearethewarmesttheyvebeenonrecord.Whentheygetupinthattemperature,theyspinoffhurricanes.Well,ifitgoesupanotherdegree,itsgonnaspawnthesewithmoreintensity,Corellsays.ThenamearcticcomesfromancientGreekmeaningLa

20、ndoftheGreatBear.Butthewarmingclimateisthreateningthisiconofthearctic,thepolarbear.Flyingabovethesub-arcticregionofHudsonBay,CanadianscientistNickLunnishuntingpolarbearsina30-yearstudythattrackstheirhealth.ItsthejobofhisassistantEvanRichardsontotakethemdownwithatranquilizerdart.Oncetranquilized,Lunn

21、carefullychecksthebearwithapole,withoutgettingtooclose.Thepolarbearisthelargestpredatoronland.Nativepeopleintheregionsayhellevenhunthumans,butnotonthedayPelleyjoinedLunn:withthetranquilizer,thebearwasawakebutimmobile.Thescientistsknewthisbearbyhistattoo.Hishistoryiswrittenchapterandverseinthebearbib

22、le.ThisistherecordbookofallthebearsthathavebeenhandledbyusorManitoba6v1.0可编写可更正Conservation,Lunnexplains.ThestudybeganattheWapuskNationalPark,becausethebearpopulationwasthoughttobethehealthiestintheworld.Lunnsannualcheckuprecordschangesinfat,dimensionsandaninventoryofweapons.Thepolarbearusesitsteeth

23、tohuntprimarilyonethingseals.Thatswherearcticwarmingcomesin.Polarbearscanonlyhuntontheice.Lunnsaystheiceisbreakingupthreeweeksearlierthanitdid30yearsgo.Hesnowfindingfemalebears55poundslighterweakermotherswithfewercubs.Askedhowthebearpopulationhaschangedsincehestartedhisresearch,Lunnsays,Whenwefirsts

24、tarteddoingthisresearch,wevedoneinventoriesinthemid-80s,inthemid-90s.Bothtimeswecameoutwithanestimateofapproximately1,200animalsforwhatisknownasthewesternHudsonBaypopulation.Thenumbersnowsuggestthatthepopulationhasdeclinedtobelow1,000.Thebearsareunlikelytosurviveasaspeciesiftheresacompletelossoficei

25、nsummer,whichthearcticstudyprojectswillhappenbytheendofthiscentury.Thereareskepticswhoquestionclimatechangeprojectionslikethat,sayingtheyrenomorereliablethanyourlocalweatherman.ButMayewskisaysarcticprojectionsdonedecadesagoareprovingaccurate.Thatsaid,theskepticshavebroughtupsomevery,veryinterestingissuesover7v1.0可编写可更正thelastfewyears.Andtheyveforcedthatwecollect.Wecanowetheskepticsaspreciseasitistoday,saysMayewski.ustothinkmoreandmoreaboutthedataavoteofthanksformakingourscienceOnebigsupporterofclimatescienceresearchistheBushadministration,spending$5billionayear.