Long-term CO2 production following permafrost thaw

• Main Authors: Bo Elberling, Anders Michelsen, Christina Schädel, Edward A. G. Schuur, Hanne H. Christiansen, Louise Berg, Mikkel P. Tamstorf, Charlotte Sigsgaard
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2013
• Subjects: Arctic; Greenland; Active layer thickness; Climate change; permafrost
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.640.5087; http://www.lter.uaf.edu/pdf/eberling_Michelsen_2013.pdf

Thawing permafrost represents a poorly understood feedback mechanism of climate change in the Arctic, but with a potential impact owing to stored carbon being mobilized1–5. 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