ReadthefollowingpassageandmarktheletterA,B, C,orD onyouranswersheettoindicatethecorrectanswertoeachofthe questions.

Expertsinclimatologyandotherscientistsarebecomingextremelyconcerned aboutthechangestoourclimatewhicharetakingplace.Admittedly,climate changeshaveoccurredonourplanetbefore.Forexample,therehavebeen severaliceagesorglacialperiods.Theseclimaticchanges,however,were differentfromthemodernonesinthattheyoccurredgraduallyand,asfaras weknow,naturally.Thechangescurrentlybeingmonitoredaresaidtobethe resultnotofnaturalcauses,butofhumanactivity.Furthermore,therateof change is becoming alarmingly rapid.

Themajorproblemisthattheplanetappearstobewarmingup.Accordingto someexperts, thiswarmingprocess,known asglobalwarming, isoccurringat arateunprecedentedinthelast10,000years.Theimplicationsfortheplanet areveryserious.Risingglobaltemperaturescouldgiverisetosuchecological disastersasextremelyhighincreasesintheincidenceoffloodingandof droughts. These in turn could have a harmfuleffect on agriculture.

ItisthoughtthatthisunusualwarmingoftheEarthhasbeencausedbyso-calledgreenhousegases,suchascarbondioxide,beingemittedintothe atmospherebycarenginesandmodernindustrialprocesses,forexample.Such gasesnotonlyaddtothepollutionoftheatmosphere,butalsocreatea greenhouseeffect,bywhichtheheatofthesunistrapped.Thisleadstothe warming up of the planet.

Politiciansarealsoconcernedaboutclimatechangeandtherearenowregular summitsonthesubject,attendedbyrepresentativesfromaround180ofthe world’sindustrializedcountries.Ofthesesummits,themostimportanttook placeinKyotoinJapanin1997.Thereitwasagreedthatthemostindustrialized countrieswouldtrytoreducethevolumeofgreenhousegasemissionsandwere given targets for this reductionof emissions.

Itwasalsosuggestedthatmoreforestsshouldbeplantedtocreateso-called sinks to absorbgreenhouse gases. Atleastpartoftheproblemof rapidclimate changehasbeencausedbytoodrasticdeforestation.Sadly,thetargetsarenot beingmet.Evenmoresadly,globalwarningsaboutclimatechangesareoften still being regarded as scaremongering.

The word “it” refers to __________