Long-term CO2 production following permafrost thaw

Abstract

The long-term loss of carbon from thawing permafrost in Northeast Greenland is quantified for 1996–2008 by repeated sediment sampling and incubation. Although the active layer has increased by >1 cm per year, there has not been a detectable decline in carbon stocks. Laboratory studies highlight the potential for fast carbon mobilization under aerobic conditions, but indicate that carbon at near-saturated conditions may remain largely immobilized for decades. Thawing permafrost represents a poorly understood feedback mechanism of climate change in the Arctic, but with a potential impact owing to stored carbon being mobilized1,2,3,4,5. 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 active-layer 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.

Cite this article

Elberling, B., Michelsen, A., Schädel, C. et al. Long-term CO₂ production following permafrost thaw. Nature Clim Change 3, 890–894 (2013). https://doi.org/10.1038/nclimate1955

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