Permafrost thawing may not cause more carbon emissions

Snow experiment site with fences on a mire, mountains in the background. Photo.
The snow manipulation experiment in the Abisko area has just revealed that permafrost thawing does not necessary lead to more net carbon emissions, as generally expected. Photo: Marcin Jackowicz-Korczynski.

Net carbon emissions that is in general expected to increase with thawing permafrost, did not increase according to new study in the Abisko region.

Massive permafrost thaw in snow experiment

In 2005, Margareta Johansson started a snow manipulation experiment on Storflaket mire in the Abisko area to record how increased snow predicted for the future would affect permafrost. The experiment has resulted in massive permafrost thaw and a thicker active layer in the manipulated plots.

Increased carbon pool compensated

A new study (Olid et al, 2020), in which Johansson is co-writer, from the same site shows that the net carbon emissions that is in general expected to increase with thawing permafrost, did not increase.  This despite the thicker active layer that almost tripled the old carbon pool available. The reason for this was that the increased carbon pool was compensated by a reduced carbon loss in the upper part of the soil, because of a sinking surface and consequent waterlogging.

The new study is published in Global Change Biology and the full reference is: Olid C, Klaminder J, Monteux S, Johansson M, Dorrepaal E. 2020. Decade of experimental permafrost thaw reduces turnover of young carbon and increases losses of old carbon, without affecting the net carbon balance. Global Change Biology 2020;00:1–13.