"Long before it's in the papers"
October 25, 2007

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Researchers: warming could cause mass extinction

Oct. 24, 2007
Courtesy University of York
and World Science staff

Glob­al warm­ing pre­dicted for the com­ing cen­turies may trig­ger a new “mass ex­tinc­tion” wit­ness­ing the de­struc­tion of more than half of an­i­mal and plant spe­cies, warn sci­en­tists at the Un­ivers­i­ties of York and Leeds in the U.K. They found a close link be­tween cli­mate and past ex­tinc­tions in a study that cov­ered the past 520 mil­lion years, cor­re­spond­ing to al­most the whole known fos­sil rec­ord.

Match­ing pub­lished es­ti­mates of past spe­cies di­vers­ity and tem­per­a­tures, the in­ves­ti­ga­tors found that ex­tinc­tions spike dur­ing warm “green­house” phases. Fu­ture pre­dicted tem­per­a­tures, they added, are with­in the range of the warmest phases as­so­ci­at­ed with mass ex­tinc­tions re­vealed in the fos­sil rec­ord.

This is “the first clear ev­i­dence that glob­al cli­mate may ex­plain sub­s­tan­tial varia­t­ion in the fos­sil rec­ord in a sim­ple and con­sis­tent” way, said the Un­ivers­ity of York’s Pe­ter May­hew. “If our re­sults hold for cur­rent warm­ing—the mag­ni­tude of which is com­pa­ra­ble with the long-term fluctua­t­ions in Earth cli­mate—they sug­gest that ex­tinc­tions will in­crease.”

Of the five ma­jor past mass ex­tinc­tions, re­search­ers said, four—in­clud­ing the one that killed off di­no­saurs 65 mil­lion years ago—are as­so­ci­at­ed with green­house phases, though crash­ing as­ter­oids have al­so been im­pli­cat­ed in some cases.

The worst-ev­er ex­tinc­tion, the end-Permian, oc­curred dur­ing one of the warmest phases and saw the die-off of an es­ti­mat­ed 95 per­cent of an­i­mal and plant spe­cies, the in­ves­ti­ga­tors added. Pre­vi­ous re­search had al­ready linked that event to high tem­per­a­tures; but “the long-term as­socia­t­ion” cov­er­ing the oth­er ex­tinc­tions was­n’t known be­fore, said the Un­ivers­ity of Leeds’ Tim Ben­ton. The find­ings ap­pear in the lat­est is­sue of the re­search jour­nal Pro­ceed­ings of the Roy­al So­ci­e­ty B.

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Global warming predicted for the coming centuries may trigger a new “mass extinction” witnessing the destruction of more than half of animal and plant species, warn scientists at the Universities of York and Leeds in the U.K. They found a close link between climate and past extinctions in a study that covered the past 520 million years, corresponding to almost the whole known fossil record. Matching published estimates of past species diversity and temperatures, the investigators found that extinctions spike during warm “greenhouse” phases. Future predicted temperatures, they added, are within the range of the warmest phases associated with mass extinctions revealed in the fossil record. This is “the first clear evidence that global climate may explain substantial variation in the fossil record in a simple and consistent” way, said the University of York’s Peter Mayhew. “If our results hold for current warming—the magnitude of which is comparable with the long-term fluctuations in Earth climate—they suggest that extinctions will increase.” Of the five major past mass extinctions, researchers said, four—including the one that eliminated the dinosaurs 65 million years ago—are associated with greenhouse phases, though crashing asteroids have also been implicated in some cases. The worst-ever extinction, the end-Permian, occurred during one of the warmest ever climatic phases and saw the die-off of an estimated 95 percent of animal and plant species, the investigators added. Previous research had already linked that event to high temperatures; but “the long-term association” covering other mass extinctions wasn’t known before, said the University of Leeds’ Tim Benton. The findings appear in the latest issue of the research journal Proceedings of the Royal Society B.