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Thursday, January 10, 2013

"Significant contribution to climate warming from the permafrost carbon feedback," by Andrew H. MacDougall, Christopher A. Avis and Andrew J. Weaver, Nature Geoscience, 5 (2012); doi:10.1038/ngeo1573

Nature Geoscience, 5(10) (2012) 719-721; doi:10.1038/ngeo1573,
Published online
 




Significant contribution to climate warming from the permafrost carbon feedback



Abstract

Permafrost soils contain an estimated 1,700Pg of carbon, almost twice the present atmospheric carbon pool1. As permafrost soils thaw owing to climate warming, respiration of organic matter within these soils will transfer carbon to the atmosphere, potentially leading to a positive feedback2. Models in which the carbon cycle is uncoupled from the atmosphere, together with one-dimensional models, suggest that permafrost soils could release 7–138Pg carbon by 2100 (refs 34). Here, we use a coupled global climate model to quantify the magnitude of the warming generated by the feedback between permafrost carbon release and climate. According to our simulations, permafrost soils will release between 68 and 508Pg carbon by 2100. We show that the additional surface warming generated by the feedback between permafrost carbon and climate is independent of the pathway of anthropogenic emissions followed in the twenty-first century. We estimate that this feedback could result in an additional warming of 0.13–1.69°C by 2300. We further show that the upper bound for the strength of the feedback is reached under the less intensive emissions pathways. We suggest that permafrost carbon release could lead to significant warming, even under less intensive emissions trajectories.

http://www.nature.com/ngeo/journal/v5/n10/abs/ngeo1573.html

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