Long-term CO sub(2) production following permafrost thaw

• Published in: Nature climate change Vol. 3; no. 10; pp. 890 - 894
• Main Authors: Elberling, Bo, Michelsen, Anders, Schaedel, Christina, Schuur, Edward AG, Christiansen, Hanne H, Berg, Louise, Tamstorf, Mikkel P, Sigsgaard, Charlotte
• Format: Journal Article
• Language: English
• Published: 01.10.2013
• Subjects: Greenland, Oestgroenland; PN, Arctic
• ISSN: 1758-678X
• DOI: 10.1038/nclimate1955

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. 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 CO sub(2) production in incubated permafrost samples. Field observations show that the active-layer thickness has increased by >1cmyr super(-1) but thawing has not resulted in a detectable decline in C stocks. Laboratory mineralization rates at 5 degree 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 degree C.