气候变化使高海拔山脉冰川正在迅速消失

气候化使海拔脉冰正在迅速消失ClimateChangeMeltingacolorfulcircusoftentspopsupatEverestBaseCampspring,astudentswillsetupcamp1,000feetdownvalley,ontheKhumbuGlacier,aresearchprojecttheystartedlastyear.Theirgoal:todeterminehowquicklytheworld’shighestglaciermelting.FromtheAlpstotheAndes,iceelevationsisdisappearingrapidly.OnEverest,theaarelikelytomanifestintwothatclimbers.First,theKhumbuGlacierwillshrink,ofitcouldpossiblybecomeimpassableforclimbers.Someday,evenBasehavetobemovedfromitslocationontheglaciertoanotherspotSecond,theKhumbuIcefallBaseCampandCampImayseeahigherofrockandiceavalanchesliketheonethatkilled16Sherpasin2014.TheIcefallnaturallymigratesdownhillbetweenthreeandfourperday,butthatcouldaccelerateastemperaturesrise.’saveragesurfacehasgonebymorethan1.5sincethe1800s,andtwo-thirdsofthattakenplacesince1975.“Itdoesntakearocketscientisttoworkoutthatifincreasethewhereiceisfrozentothebedrock,theholdisgoingtoweakenedbecomeincreasinglyunstablethemorelikelytodetachfromthebedrock,saysDuncanQuincey,ofgeomorphologyatUniversityLeeds,intheUK.HeissupervisingtheresearchofKingandScottWatson,thePh.D.studentswillspendfewweeksontheglacierspring.“InplacesliketheIcefallwe’veseenthesetragicandIthinkitfairtoitsymptomaticof-elevationwarming.”

It'snotjustunstableicethatposesrisk—meltwaterisconcerning,too.MeltwaternaturallypoolsthesurfaceofboththeKhumbuGlacier,’ssouthside,theRongbukGlacieronthenorthsideduringthewarmermonths,thendrainsandreformsasseasonschange.Theissuenowthatthepondsdon’tbutcoalesceintosmalllakes.Anpaperco-authoredbyWatson,Quincey,andtwoothersupervisorsthatthepondsthelowerpartoftheKhumbuGlacierincreasedinsizeby84percent2015.anddepthofthelakesontheKhumbuGlaciervary.Someareseveralhundredfeetlongandothersaredeepandwideenoughmerittheuseofboats.KingWatsonwilluseaninflatablekayaktodeploytemperaturetheponds.(Infact,theywillsetrecordhighestaltitudekayaking.They’vealreadyintouchwithGuinnessWorldRecords.)“AcrossEasternareaofHimalayatherearemoreandmore[lakes]developing,”saysQuincey.’spositivefeedbackcycle:asmallabsorbsmoreradiationthanitwoulditwasrock,andthatthewater,whichmeltsmoreandthepondgetsbigger.”Atsomepoint,thesideofonethelakesontheKhumbuGlaciermayway,sendingwaterdebrisdownintointheKhumbuValleybelow.researchersaren’tpredictingsuchanoutburstanytimebutitstillaconcern,says."WhilethelastthingIwanttodoisstartsayingthere'simminentdisaster,youreallydon'tthereattheheadofthatvalley.”abursthashappenedbefore.1985,DigTsho,aglacialinNationalParkburstthroughthemorainedamholdingback,destroyinganewhydropowerstation,30houses,and14bridgesintheKhumbuValley.ImjaTsho,alargeglacialintheEverestregion,isjusttheChukhungValley,whichhasanumberofvillagesthatcatertotrekkers,andhasbeenwidelyrecognizedforitspotentialtofloodthevalleybelow,researcherssay.KingandspentweekstheGlacierlastfall,whentheyreturninMaytheydeploytheirtemperaturesensorstakephotostoinformtheir3Delevationmodeloficecliffsaroundtheglacier.They’realsousingsatelliteimagerytothesizeofthepondsandbuildingarobottovolume.Theirresultswillhelpshedlighthowalldebris-coveredglaciersthecentralHimalayarespondingthetemperatureinasimilarw