UniversityofYorkbiologistPeterMayhewrecentlyfoundthatglobalwarmingmightactuallyincreasethenumberofspeciesontheplanet，contrarytoapreviousreportthathighertemperaturesmeantfewerlifeforms—areportmatwashisown.
InMayhew’sinitial2008study，lowbiodiversityamongmarineinvertebrates(无脊椎动物)appearedtocoincidewithwarmertemperaturesonEarthoverthelast520millionyears.ButMayhewandhiscolleaguesdecidedtoreexaminetheirhypothesis，thistimeusingdatathatwere“afairersampleofthehistoryoflife.”砌thisnewcollectionofmaterial.theyfoundacompletereversaloftherelationshipbetweenspeciesrichnessandtemperaturefromwhattheirpreviouspaperargued：thenumberofdifferentgroupspresentinthefossilrecordwashigher，ratherthanlower，durin9“greenhousephases.”
Theirpreviousfindingsrestedonanassumptionthatfossilrecordscanbetakentorepresentbiodiversitychangesthroughouthistory.Thisn’tnecessarilythecase.becausetherearecertainperiodswithhigher.qualityfossilsamples.andsomethataremuchmoredifficulttosamplewell.Awareofthisbias.Mayhew’steamuseddatathatstandardizedthenumberoffossilsexaminedthroughouthistoryandaccountedforothervariableslikesealevelchangesthatmightinfluencebiodiversityintheirnewstudytoseeiftheiroldresultswouldholdup.
Twoyearslater，theresultsdidnot.Butthenwhydoesn'tlifeincreasinglyemergeonEarthasourtemperaturesgetwarmer?
Whiletheswitchmaypromptsometoassertthatclimatechangeisnothazardoustolivingcreatures，Mayhewexplainedthatthetimescalesinhisteam’sstudyarehuge--over500millionyears--andthereforeinappropriatefortheshorterperiodsthatwemightlookatashumansconcernedaboutglobalwanning.Manyglobalwarmingconcernsarefocusedonthenextcentury.Hesaid——andthelifetimeofaspeciesistypicallyoneto10millionyears.
“Idoworrythatthesefindingsvillbeusedbytheclimateskepticcommunitytosay‘look.Climatewarmingisfine。hesaid.Nottomentionthenumerousotherthingsweseemtodotocreateastormofthreatstobiodiversity—thinkofwhathabitat(栖息地)destruction，overfishing，andpollutioncandoforaspecies’viability(生存力).Thosethings，Mayhewexplained，givetheorganismsafargreaterchallengeincopingwithclimatechangethantheywouldhavehadintheabsenceofhumans.
“Ifweweretorelaxallthesepressuresonbiodiversityandallowtheworldtorecoverovermillionsofyearsinawarmerclimate.thenmypredictionisitwouldbeanimprovementinbiodiversity，”hesaid.Soitlookslikeweneedtocurbourrecklesstreatmentoftheplanetfirst，ifwewanttoeventuallyseeasurgeinthenumberofspeciesontheplanetastemperaturesgetwarmer.Wedon'thave500millionyearstowait.
