Pathway-dependent fate of permafrost region carbon

Abstract

Permafrost soils in the high northern latitudes contain a substantial amount of carbon which is not decomposed due to frozen conditions. Climate change will lead to a thawing of at least part of the permafrost, implying that the stored carbon will become accessible to decomposition and be released to the atmosphere. We use a land surface model to quantify the amount of carbon released up until 2300 and determine the net carbon balance of the northern hemisphere permafrost region under climate warming following the RCP scenarios 2.6, 4.5, and 8.5. Here we show for the first time that the net carbon balance of the permafrost region is not just strongly dependent on the overall warming, but also on the CO2 concentration pathway. As a result moderate warming scenarios may counterintuitively lead to lower net carbon emissions from the permafrost region than low warming scenarios.