Potential carbon emissions dominated by carbon dioxide from thawed permafrost soils

• Published in: Nature Climate Change
• Main Authors: Schädel, C, Bader, MK-F, Schuur, EAG, Biasi, C, Bracho, R, Čapek, P, De Baets, S, Diáková, K, Ernakovich, J, Estop-Aragones, C, Graham, DE, Hartley, IP, Iversen, CM, Kane, E, Knoblauch, C, Lupascu, M, Martikainen, PJ, Natali, SM, Norby, RJ, O’Donnell, JA, Chowdhury, TR, Šantrůčková, H, Shaver, G, Sloan, VL, Treat, CC, Turetsky, MR, Waldrop, MP, Wickland, KP
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2016
• Subjects: Environmental sciences; Ecosystem ecology; Arctic; permafrost; Study of Environmental Arctic Change
• Online Access: http://hdl.handle.net/10871/22234; https://doi.org/10.1038/nclimate3054

Published Increasing temperatures in northern high latitudes are causing permafrost to thaw1, making large amounts of previously frozen organic matter vulnerable to microbial decomposition2. Permafrost thaw also creates a fragmented landscape of drier and wetter soil conditions3, 4 that determine the amount and form (carbon dioxide (CO2), or methane (CH4)) of carbon (C) released to the atmosphere. The rate and form of C release control the magnitude of the permafrost C feedback, so their relative contribution with a warming climate remains unclear5, 6. We quantified the effect of increasing temperature and changes from aerobic to anaerobic soil conditions using 25 soil incubation studies from the permafrost zone. Here we show, using two separate meta-analyses, that a 10 °C increase in incubation temperature increased C release by a factor of 2.0 (95% confidence interval (CI), 1.8 to 2.2). Under aerobic incubation conditions, soils released 3.4 (95% CI, 2.2 to 5.2) times more C than under anaerobic conditions. Even when accounting for the higher heat trapping capacity of CH4, soils released 2.3 (95% CI, 1.5 to 3.4) times more C under aerobic conditions. These results imply that permafrost ecosystems thawing under aerobic conditions and releasing CO2 will strengthen the permafrost C feedback more than waterlogged systems releasing CO2 and CH4 for a given amount of C. Financial support was provided by the National Science Foundation Vulnerability of Permafrost Carbon Research Coordination Network Grant no. 955713 with continued support from the National Science Foundation Research Synthesis, and Knowledge Transfer in a Changing Arctic: Science Support for the Study of Environmental Arctic Change Grant no. 1331083. Author contributions were also supported by grants to individuals: Department of Energy, Office of Biological and Environmental Research, Terrestrial Ecosystem Science (TES) Program (DE-SC0006982) to E.A.G.S.; UK Natural Environment Research Council funding to I.P.H. and C.E.-A. (NE/K000179/1); German ...