Nature Geosci. http://doi.org/jbz (2012)

Credit: © HEMERA/THINKSTOCK

Permafrost soils contain a large reservoir of carbon, double the current atmospheric carbon. Climate warming is likely to lead to permafrost thawing, which will allow transfer of the stored carbon to the atmosphere. This will lead to a positive feedback which will increase warming.

Andrew MacDougall and colleagues, at the University of Victoria, British Columbia, Canada, used a coupled global climate model to investigate the possible temperature increase associated with the permafrost carbon release. They investigated different warming scenarios associated with anthropogenic emissions pathways.

They found that permafrost soils could release 68–508 Pg carbon (of the estimated 1,700 Pg carbon stored) by 2100. This amount of carbon release could cause significant additional warming of 0.13–1.69 °C by 2300, independent of emissions pathways in the twenty-first century.