Long-term CO2 production following permafrost thawing

Abstract

Thawing permafrost represents a poorly understood feedback mechanism of climate change in the Arctic, but with a potential impact owing to stored carbon being mobilized^1–5. We have quantified the long-term loss of carbon (C) from thawing permafrost in Northeast Greenland from 1996 to 2008 by combining repeated sediment sampling to assess changes in C stock and >12 years of CO₂ production in incubated permafrost samples. Field observations show that the activelayer thickness has increased by >1 cm yr^-1 but thawing has not resulted in a detectable decline in C stocks. Laboratory mineralization rates at 5 C resulted in a C loss between 9 and 75%, depending on drainage, highlighting the potential of fast mobilization of permafrost C under aerobic conditions, but also that C at near-saturated conditions may remain largely immobilized over decades. This is confirmed by a three-pool C dynamics model that projects a potential C loss between 13 and 77% for 50 years of incubation at 5 C.

Citation

Elberling, B.; Michelsen, A.; Schadel, C.; Schuur, E.A.G.; Christiansen, H.H.; Berg, L.; Tamstorf, M.P.; Sigsgaard, C. 2013. Long-term CO₂ production following permafrost thawing. Nature Climate Change. 3: 890–894.