大学英语四级美文：互联网的碳足迹思维导图

Theinternetreleasesaround300mtonnesofCO2ayear–asmuchasallthecoal,oilandgasburnedinTurkeyorPoland,ormorethanhalfofthefossilfuelsburnedintheUK.

Allcarbonfootprintsarehardorimpossibletopindownaccurately,buttheinternetisaparticularlycomplexcase.Thisisn'tjustduetothefactthatthe"net"consistsofmillionsorevenbillionsofmachinesownedbycountlesspeopleandcompanies.There'salsoanotherproblem:evenifweknewexactlyhowmuchenergyallthesedevicesconsumed(whichwedon't),westillwouldn'tknowhowmuchofthatenergywasspentonofflinejobs(suchascreatingdocumentsinMicrosoftOffice)andhowmuchwasspentononlinejobs(suchasemailingthosedocumentstoafriendorcolleague).

It'spossible,nonetheless,totakearoughstabatworkingouttheinternet'scarbonfootprint.Agoodplacetostartistheworld'sdatacentres–buildingspackedtoptobottomwithserversfullofthewebpages,databases,onlineapplicationsanddownloadablefilesthatmakethemodernonlineexperiencepossible.Datacentresuselotsofelectricity,bothforpoweringthemachinestheycontainand–allimportantly–fortheairconditioningneededtokeeptheserversfromoverheating.

AccordingtoareportbyGartner,datacentresalreadyaccountforaroundaquarteroftheenergyconsumed(andthecarbonemitted)bytheinformationandcommunicationtechnology(ICT)sectorasawhole.Inotherwords,aroundhalfapercentofglobalCO2emissions.

ByGartner'sfigures,theworld'sPCsandmonitorsareevenmorepowerhungry,accountingforaround40%ofthetotalICTenergydemandand0.8%ofglobalCO2emissions.Ifwedecided(somewhatarbitrarily)thathalfoftheemissionsfromalltheselaptopanddesktopmachinesweredowntointernet-basedactivity,andthenaddontheemissionsfromthedatacentresthatmakeallthisonlineactivitypossible,thentheinternetwouldclockinataround1%ofalltheCO2emissionsreleasedfromburningfossilfuels.Putanotherway,theinternetreleasesaround300mtonnesofCO2–asmuchasallthecoal,oilandgasburnedinTurkeyorPolandinoneyear,ormorethanhalfofthoseburnedintheUK.

ThesefigurestieinfairlywellwithastudybytheUK'smarkettransformationprogramme,whichconcludedthat343.5milliontonnesofCO2wasdowntoconsumerandcommercialICTin2005–equivalenttoaround1.2%ofcurrentfossil-fuelCO2emissions.ICT'sfootprintisduetoclimbby60%by2030,thesamereportsuggests.Ifthatwastohappen,andglobalemissionshadalreadyfallenbythen,asclimatechangeexpertssuggesttheymust,thentheinternet'sshareoftotalcarbonoutputwouldclimbsignificantlyhigherstill.

Allthisdependsonwhathappensbetweennowandthen,ofcourse.Companieshavealreadybeenexploringtechnologiesthatcantaketheheatfromdatacentresandusethemtowarmnearbybuildings,therebyreducinginternalair-conditioningrequirementsandlocaldemandforheatingfuels.AndIceland,whichhasanabundanceofrenewable,low-carbonenergyisanglingtobetheworld'sdata-centrecapital.

Inthemeantime,it'sinterestingtonotethat1%isaboutthesameproportionasprintingandpaper-basedpublishingrepresentsintheUK.Thecomparisonisn'tentirelyvalid,forawholehostofreasons,butthefactremainsthatdespiteecologicalclaimsforthevirtualeconomy,thedigitaleramaybenolessenergy-hungrythanthepaper-basedworldof20yearsago.Partofthereasonistheso-calledreboundeffect–thephenomenonthatwhensomething(inthiscasethestoringandinterrogationofdata)becomescheaperandmoreenergy-efficient,weoftenendupsimplydoingmoreofit,withtheresultthatthereisnonetreduction,orevenarise,incostorimpact.

Ontheotherhand,theinternetislikelytobecrucialtoanymovetoalow-carbonworld.Withoutitscapacitytocarrythehugeflowsofenergydata,therecouldbeno"smartgrid",forexample,andwithoutonlinevideoconferencingitwouldbemuchhardertoreducethenumberofbusinessflightsincomingyears.Ultimately,then,it'snotjusttechnologicaldevelopmentsthatwillaffectthegrowingcarbonfootprintoftheInternet.Justasimportantishowwechoosetouseit.

【重点单词及短语】

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