Climate study warns of greenhouse gas feedback loop

Icebergs off Greenland's eastern coast Keystone

Many current climate models could be underestimating the long-term consequences of global warming, says an international study with Swiss participation. 

Researchers from 17 countries, including a team from the Oeschger Centre for Climate Change ResearchExternal link at the University of Bern, combed through data going back 3.5 million years and analysed several warm periods. 

During these periods, the high latitudes near the poles heated up more than the tropics, said a statement from the University of Bern, Oregon State University and the University of New South Wales. 

The scientists said this meant the thawing of permafrost released additional carbon dioxide and methane into the atmosphere, which would drive global warming even more. 

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If humanity succeeded in limited global warming to two degrees Celsius more than in pre-industrial levels, the risk would be “somewhat small” of a self-reinforcing greenhouse gas feedback loopExternal link, they concluded. However, they said future emissions scenarios would have to take into consideration the high amount of additional carbon dioxide. 

The 59 researchers had focused on the issue of past warm periods at a workshop in Bern in April. The resulting study has now been published in the journal Nature Geoscience.