雅思making everydorp count答案.docx
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雅思making everydorp count答案.docx
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雅思makingeverydorpcount答案
雅思makingeverydorpcount答案
MakingEverydropCount
AThehistoryofhumancivilisationisentwinedwiththehistoryofthewayswehavelearnedtomanipulatewaterresources.Astownsgraduallyexpanded,waterwasbroughtfromincreasinglyremotesources,leadingtosophisticatedengineeringeffortssuchasdamsandaqueducts.AttheheightoftheRomanEmpire,ninemajorsystems,withaninnovativelayoutofpipesandwell-builtsewers,suppliedtheoccupantsofRomewithasmuchwaterperpersonasisprovidedinmanypartsoftheindustrialworldtoday.
BDuringtheindustrialrevolutionandpopulationexplosionofthe19thand20thcenturies,thedemandforwaterrosedramatically.Unprecedentedconstructionoftensofthousandsofmonumentalengineeringprojectsdesignedtocontrolfloods,protectcleanwatersupplies,andprovidewaterforirrigationandhydropowerbroughtgreatbenefitstohundredsofmillionsofpeople.Foodproductionhaskeptpacewithsoaringpopulationsmainlybecauseoftheexpansionofartificialirrigationsystemsthatmakepossiblethegrowthof40%oftheworld'sfood.Nearlyonefifthofalltheelectricitygeneratedworldwideisproducedbyturbinesspunbythepoweroffallingwater.
CYetthereisadarksidetothispicture:
despiteourprogress,halfoftheworld'spopulationstillsuffers,withwaterservicesinferiortothoseavailabletotheancientGreeksandRomans.AstheUnitedNationsreportonaccesstowaterreiteratedinNovember2001,morethanonebillionpeoplelackaccesstocleandrinkingwater;sometwoandahalfbilliondonothaveadequatesanitationservices.Preventablewater-relateddiseaseskillanestimated10,000to20,000childreneveryday,andthelatestevidencesuggeststhatwearefallingbehindineffortstosolvetheseproblems.
DTheconsequencesofourwaterpoliciesextendbeyondjeopardisinghumanhealth.Tensofmillionsofpeoplehavebeenforcedtomovefromtheirhomes—oftenwithlittlewarningorcompensation—tomakewayforthereservoirsbehinddams.Morethan20%ofallfreshwaterfishspeciesarenowthreatenedorendangeredbecausedamsandwaterwithdrawalshavedestroyedthefree-flowingriverecosystemswheretheythrive.Certainirrigationpracticesdegradesoilqualityandreduceagriculturalproductivity.Groundwateraquifers*arebeingpumpeddownfasterthantheyarenaturallyreplenishedinpartsofIndia,China,theUSAandelsewhere.Anddisputesoversharedwaterresourceshaveledtoviolenceandcontinuetoraiselocal,nationalandeveninternationaltensions.
*undergroundstoresofwater
EAttheoutsetofthenewmillennium,however,thewayresourceplannersthinkaboutwaterisbeginningtochange.Thefocusisslowlyshiftingbacktotheprovisionofbasichumanandenvironmentalneedsastoppriority—ensuring'someforall,'insteadof'moreforsome'.Somewaterexpertsarenowdemandingthatexistinginfrastructurebeusedinsmarterwaysratherthanbuildingnewfacilities,whichisincreasinglyconsideredtheoptionoflast,notfirst,resort.Thisshiftinphilosophyhasnotbeenuniversallyaccepted,anditcomeswithstrongoppositionfromsomeestablishedwaterorganisations.Nevertheless,itmaybetheonlywaytoaddresssuccessfullythepressingproblemsofprovidingeveryonewithcleanwatertodrink,adequatewatertogrowfoodandalifefreefrompreventablewater-relatedillness.
FFortunately—andunexpectedly—thedemandforwaterisnotrisingasrapidlyassomepredicted.Asaresult,thepressuretobuildnewwaterinfrastructureshasdiminishedoverthepasttwodecades.Althoughpopulation,industrialoutputandeconomicproductivityhavecontinuedtosoarindevelopednations,therateatwhichpeoplewithdrawwaterfromaquifers,riversandlakeshasslowed.Andinafewpartsoftheworld,demandhasactuallyfallen.
GWhatexplainsthisremarkableturnofevents?
Twofactors:
peoplehavefiguredouthowtousewatermoreefficiently,andcommunitiesarerethinkingtheirprioritiesforwateruse.Throughoutthefirstthree-quartersofthe20thcentury,thequantityoffreshwaterconsumedperpersondoubledonaverage;intheUSA,waterwithdrawalsincreasedtenfoldwhilethepopulationquadrupled.Butsince1980,theamountofwaterconsumedperpersonhasactuallydecreased,thankstoarangeofnewtechnologiesthathelptoconservewaterinhomesandindustry.In1965,forinstance,Japanusedapproximately13milliongallons*ofwatertoproduce$1millionofcommercialoutput;by1989thishaddroppedto3.5milliongallons(evenaccountingforinflation)—almostaquadruplingofwaterproductivity.IntheUSA,waterwithdrawalshavefallenbymorethan20%fromtheirpeakin1980.
HOntheotherhand,dams,aqueductsandotherkindsofinfrastructurewillstillhavetobebuilt,particularlyindevelopingcountrieswher
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