泛读教程4IsWeatherGettingWorseWord文件下载.docx

泛读教程4IsWeatherGettingWorseWord文件下载.docx

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Asyoureadthis,flipyoureyesovertothewindow.Theskyisclear,thewindlight,andthesunbrilliant.Ormaybenot－MotherNatureisfullofsurprisesthesedays.Thecalendarsaysit'

sspring,buttherecouldjustaseasilybeawinterblizzard,asummerswelter,oranautumncoldsnapontheothersideofthatglasspane.Almostinaninstant,itseems,theweathershiftsfromoneseasontoanother.Andwhereveritswings,itseemsincreasinglylikelytobeextreme.

ConsiderwhatMotherNatureslungourwaylastyearinMay,typicallythesecondworstmonthfortornadoes.Inlessthan24hours,morethan70hellholesofwindrampagedthroughOklahomaandKansas,killing49andcausingmorethan$1billionindamages.InJune,itwasheat,astheNortheastbeganroastingthroughweeksoftheworstdroughtsincethe1960s;

256peopledied.ThisyearinJanuary,blizzardspoundedtheU.S.fromKansastotheAtlanticOcean.InApril,25inchesofsnowfellonpartsofNewEngland.

WhyhasourweathergonewildIt'

sthequestioneveryone'

sasking,butaverytoughonetoanswer.Althoughmanyscientistsstillaren'

tconvincedthatithasgonewild,somehavebegunsaying－cautiously,hesitantly－thatextremeweathereventsareoccurringwithmorefrequencythanatanytimeinthiscentury,eventsconsistentwiththeprofileofawarmingworld."

Globalwarmingisreal,"

saysKevinE.Trenberth,headoftheClimateAnalysisSectionoftheCenterforAtmosphericResearchinBoulder,Colorado."

Themeantemperaturesaregoingup.Thekeyquestionis:

WhatwillitdolocallyIthinkwe'

regoingtostartfeelingitseffectsinthechangesonextremes."

Thatdoesn'

tmeanyoucanindictweirdweatherinyourneckofthewoodsasproof.MotherNatureknowshowtohidehertracks.Shehurlsatorrentialdownpourtodayandadroughttomorrowfollowedbygentlerainthenextweek.Tounderstandapatterninnaturalvariability,youcan'

tlookintothesky;

youhavegottostudydata.Andforahostofreasons,thatisn'

teasy.

Buttallyingupthedamageis.Inthelast20years,thiscountryhasbeenwhackedby$I70billionworthofweather-relateddisasters－hurricanes,droughts,floods,andtornadoes.Thirty-eightsevereweathereventsoccurredinasingledecade,between1988and1999;

seveneventsoccurredin1998alone－themostforanyyearonrecord.

Globally,insurancecompaniesarecallingita"

catastrophetrend"

.InareportissuedlastDecember,MunichRe,theworld'

slargestreinsurer,orinsurerofinsurancecompanies,notedthatthenumberofnaturaldisastershasincreasedmorethanfourfoldsincethe1950s.Earthquakes,whicharenotweather-related,causednearlyhalfthedeathsinthosecatastrophes;

storms,floods,andotherweatherwoeskilledtheotherhalf.In1999,thenumberofcatastrophesworldwidehit755,surpassingtherecordof702setonlytheyearbefore.

Initsfive-pointlistofcausesforincreaseddamageclaims,MunichReblamedpopulationgrowthfirst,climatechangefifth.Criticsmaywellseizeuponthistodiminishclaimsthattheweatherisgettingworse,buttakentogether,it'

samorefrighteningpicture.Thankstoswellingpopulationsincitiesandalongcoastalareas,moreofEarth'

spassengersarelivinginthewrongplaceatthewrongtime.

Still,thestatisticsmeteorologistshavecollectedonextremeweathereventsaren'

tenoughtoprovethattheweatherisgettingworse.Bytheirverydefinition,extremeeventshappeninfrequently,andnoonehasbeencollectingscientificallysounddatalongenoughtoknowhowcommontheyare.Forexample,astormthathappensonceacenturymightrequiretwomillennia'

sworthofstormdatatodrawconclusions.Totopitoff,thecomputermodelsscientistsusetostudyclimatecrunchnumbersonascaleofcenturiesatatime."

Ideally,you'

dlikedatasetsthatgobackseveralhundredyears,"

saysPhilipArkin,deputydirectoroftheInternationalResearchInstituteforClimatePredictionattheLamont-DohertyEarthObservatoryinNewYork."

Buttheyjustdon'

texist.TheU.S.datagoback50years.BeforeWorldWarII,it'

sverydifficulttocomeupwithgoodnumbers.Wehavesomedataonheavyraineventsbefore1900,butthere'

snothinguseful."

Evenifscientistscouldfindgoodnumbers,computerresolutionisstilltoocoarsetobeabletoforecasthowsomethingassimpleaswarmingmightaffectclimateinspecificspotsontheglobe.Thesmallestamountofspaceonland,sea,ice,andairthatscientistscanstudyisaboutthesizeofVirginia.Iftheycrankuptheresolutionby50percenttofocusonanareahalfthatsize,theypayforitincomputingtime－acalculationthattook10daystoperformmightnowneedthreemonths.

KeithDixon,aresearchmeteorologistattheNationalOceanicandAtmosphericAdministration'

sGeophysicalFluidDynamicsLaboratoryinNewJersey,recallsoncehewasbeingaskedpreciselywhatglobalwarmingwouldmeanforstateskiresorts.Moresnow（Good.）Ormorerain（Bad.）"

Icanunderstandwhybusinesspeopleorpoliticiansask.Ifyouwanttocutfuel,spendmoney,andmakedecisions,youneedtoknowwhyyoushouldbedoingthis."

Addshiscolleague,TomKnutson:

"

Icancertainlysympathizewiththem.Butwecan'

tanswerit."

Since1995,theliteraturehassuggestedthattherecouldbefewerfrosts,moreheatwaves,moredroughts,moreintenserainfalls,tropicalcyclones,andhurricanesinthe21stcenturywhenandifCO2levelsdouble.Buttheseprojectionsranklowontheconfidencescalebecausescientistscannotsaydefinitivelyifandhowtheeventsmightoccur.

Allofwhichdoesn'

tdotheaveragecitizenmuchgood.Hedoesn'

tworryabout30-to-100-yearshiftsintheclimate.Whatgetshimisday-to-dayweather:

Thisheat'

skillingme."

Cropshavefailedherefiveyearsinarow."

Therehavebeenthreebadtornadoesinasmanyweeks."

Weliveinasocietyuniquelyprivilegedtolearnaboutweatherevents－andtofearthem.TheCenterforMediaandPublicAffairs,awatchdoggroupbasedinWashington,D.C.,reportsthatmediacoverageofweatherdisastersmorethandoubledfrom1997to1998alone.

Probablyasaresult,peoplearestartingtoblameharshweatheronglobalwarming.Politiciansaretoo.JerryMahlman,directoroftheGFDL,advisestheWhiteHouseonclimatechange.HerememberssittinginaconferencewithVicePresidentGore,whoasked:

Canwesaythatstormswillbemoreextremeinthegreenhouse-enhancedearth"

Thescientistdidn'

tflinchashereplied,"

No."

Gore'

sshouldersseemedtocrumple.

Globally,the1990sstoodasthewarmestdecadeforwhichwehaverecords.Scientistsalreadypredictthatby2100,EarthcouldwarmupanothertodegreesFahrenheit.Mostofusthinkheatwhenwethinkglobalwarming.Scientiststhinkice.They'

reworriedaboutwhatwillhappenwhenallthatextraheathitstheiceatEarth'

spoles.Adominanthypothesissaysthatthewatercyclewillspeedup:

Heatwillhastenoceanevaporation,andbecausehotaircanholdmoremoisture,itcouldallbewhiskedawaytorainmoreuponourheads.

FiveyearsagotheIntergovernmentalPanelonClimateChange,aninternationalcollaborationof2000scientists,theorizedasmuchinawell-publicized56-pagereport.Thatsameyear,ateamofscientistsledbyTomKarl,nowdirectoroftheNationalClimaticDataCenter（NCDC）,studied80yearsof.dataandconfirmedanincreaseinextremeprecipitationevents,alteredpatternsofrainanddrought,andrisingtemperaturessince1970.Butthescientistscautionedthatthestudyanalyzedonly80yearsofdata,confineditselftotheUnitedStates－whichoccupiesamere2percentoftheglobe－andfoundnothingoutoftherealmofpurechance.

Withinmonthscameanother,strongerpieceofreal-worlddata,naileddownbyoneofthemencaughtinthatJanuarysnowstorm.Siftingthroughhistoricaldata,Trenberthhadfoundthatmore,longer,andstrongerElNiňoshaveoccurredduringthelast20yearsthanintheprevious120years.Thatwasunusual,achanceof1in2000.ElNiňo,theperiodicwarmingoftheequatorialPacificthatinducesstormsandotherclimaticevents,historicallyoccursonceeverythreetosevenyearsandlastsforuptotwoyears.ButevenasTrenberthpresentedhisfindingsataconferenceinMelbourne,Australia,thePacificwasexperiencinganodd,doubleElNiňo:

Thefirsthadlastedfrom1991to1993,aweakeronefrom1994to1995.TrenberthfloatedanidealpasttheaudienceinhisnativeNewZealandaccent:

Couldthisbeduetoglobalwarming

Theidea,Trenberthmodestlyrecalls,causedsomethingofastirintheaudience.Scientistsfoundthemselveswondering:

Whatwouldhappenifoneofnature'

sstormmachines－notcompletelyunderstoodbutstilladheringtorhythmsasregularastheseasons－werepressedintoservicebyglobalwarming

ArchaeologicalevidencesuggestsElNiňohasbeenaroundforthousands,possiblymillionsofyears.Aknowninstigatorofstorms,floods,droughts,andsecondaryeffectslikefires,theElNiňo-SouthernOscillationcouldgoalongwaytowardexplainingmanyweatherextremes.Undernormalcircumstances,seasurfacetemperaturesriseinthetropicalPacific,fuelingstrongthunderstorms.Likeavastclimaticmailbag,ElNiňo-enhancedactivityhand-deliversheatand