阅读理解

EarlierthismonththeObamaAdministrationcalledforincreasedprotectionoftheworld'smostsoutherncontinentAntarctica．ScientistssayclimatechangeandhumanactivityhaveincreasinglyledtothemeltingofmassivepiecesofAntarcticice．Thedisappearanceoficewillnotonlyaffectwildlifeintheareasuchassealsandpenguins．Themeltingwillalsocauseoceansandseasaroundtheworldtorise．

Thisrepresentsamajorthreatespeciallytocoastalareas．ForexampletheancientcityofVeniceItalyhaslongbeenthreatenedbyrisingsealevels．Thesituationismadeworsebythefactthatitsancientbuildingsbuiltonabodyofwatercalledalagoon(淡水湖)areslowlysinking．Whenthecitywasfoundedabout1600yearsagotheleveloftheAdriaticSeawasalmosttwometerslowerthanitistoday．

Risingsealevelsarenottheonlythreat．ThesaltywaterisalsodestroyingVenice'sfamousbuildingsandartworks．TheItaliangovernmentistryingtofixtheproblemwiththeconstructionofaseven-billion-dollarsystemofmovingfloodbarriers．

ClimatechangeisalsoleadingtothemeltingoficeinotherareassuchasMountKilimanjaroinnortheasternTanzania．ItisthehighestpointinAfricameasuringalmost6000meters．Themountainsupportsfivevegetationzonesandmanykindsofanimals．

Theiceglaciersonthemountainaredisappearingveryquickly．Thiswillhaveabadeffectonthemountain'secosystemsandonTanzania'stravelindustry．Alsoavaluablerecordofthousandsofyearsofweatherhistorywillalsobelostiftheicemelts．Scientistsstudypiecesofglaciertounderstandweatherpatternsfromthousandsofyearsago．

IntheUnitedStatestheicymassesinGlacierNationalParkinMontanamaysooncompletelydisappearbecauseofclimatechange．In1850therewereanestimated150glaciersinthemorethan400000hectarepark．

Thereare26glaciersremainingtoday．Scientistsestimatethattheglacierswillbegoneby2030．Warmingtemperaturesarealsothreateningthemanykindsofplantsandanimalsthatliveinthismou