英文阅读理解英文阅读理解PassageFourteen(AntarcticaandEnvironment)Antarcticahasactuallybecomeakindofspacestation–auniqueobservationpostfordetectingimportantchangesintheworld’senvironment.Remotefrommajorsourcesofpollutionandthecomplexgeologicalandecologicalsystemsthatprevailelsewhere,Antarcticamakespossiblescientificmeasurementsthatareoftensharperandeasiertointerpretthanthosemadeinotherpartsoftheworld.GrowingnumbersofscientiststhereforeseeAntarcticaasadistant-early-warningsensor,wherepotentiallydangerousglobaltrendsmaybespottedbeforetheyshowuptothenorth.Onepromisingfieldofinvestigationisglaciology.ScholarsfromtheUnitedStates,Switzerland,andFrancearepursuingsevenseparatebutrelatedprojectsthatreflecttheirconcernforthehealthoftheWestAntarcticIceSheet–aconcerntheybelievetheworldatlargeshouldshare.TheTransantarcticMountain,someofthemmorethan14,000feethigh,dividethecontinentintotwoverydifferentregions.Thepartofthecontinenttothe“east”ofthemountainsisahighplateaucoveredbyanicesheetnearlytwomilesthick.“West”ofthemountain,thehalfofthecontinentsouthoftheAmericasisalsocoveredbyanicesheet,buttheretheicerestsonrockthatismostlywellbelowsealevel.IftheWestAntarcticIceSheetdisappeared,thewesternpartofthecontinentwouldbereducedtoasparseclusterofisland.Whileiceandsnowareobviouslycentraltomanyenvironmentalexperiments,othersfocusonthemysterious“dryvalley”ofAntarctica,valleysthatcontainlittleiceorsnoweveninthedepthsofwinter.SlashedthroughthemountainsofsouthernVictoriaLand,thesevalleysonceheldenormousglaciersthatdescended9,000feetfromthepolarplateautotheRossSea.Nowtheglaciersaregone,perhapsacasualtyoftheglobalwarmingtrendduringthe10,000yearssincetheiceage.Eventhesnowthatfallsinthedryvalleysisblastedoutbyviciouswindsthatroarsdownfromthepolarplateautothesea.Leftbarearespectaculargorges,rippledfieldsofsanddunes,clustersofboulderssculpturedintofantasticshapesby100-mile-an-hourwinds,andanauraofextraterrestrialdesolation.Despitetheunearthlyaspectofthedryvalleys,somescientistsbelievetheymaycarryamessageofhop