TY  - JOUR
A1  - Knoblauch, Christian
A1  - Beer, Christian
A1  - Liebner, Susanne
A1  - Grigoriev, Mikhail N.
A1  - Pfeiffer, Eva-Maria
T1  - Methane production as key to the greenhouse gas budget of thawing permafrost
JF  - Nature climate change
N2  - Permafrost thaw liberates frozen organic carbon, which is decomposed into carbon dioxide (CO2) and methane (CH4). The release of these greenhouse gases (GHGs) forms a positive feedback to atmospheric CO2 and CH4 concentrations and accelerates climate change(1,2). Current studies report a minor importance of CH4 production in water-saturated (anoxic) permafrost soils(3-6) and a stronger permafrost carbon-climate feedback from drained (oxic) soils(1,7). Here we show through seven-year laboratory incubations that equal amounts of CO2 and CH4 are formed in thawing permafrost under anoxic conditions after stable CH4-producing microbial communities have established. Less permafrost carbon was mineralized under anoxic conditions but more CO2-carbon equivalents (CO2Ce) were formed than under oxic conditions when the higher global warming potential (GWP) of CH4 is taken into account(8). A model of organic carbon decomposition, calibrated with the observed decomposition data, predicts a higher loss of permafrost carbon under oxic conditions (113 +/- 58 g CO2-C kgC(-1) (kgC, kilograms of carbon)) by 2100, but a twice as high production of CO2-Ce (241 +/- 138 g CO2-Ce kgC(-1)) under anoxic conditions. These findings challenge the view of a stronger permafrost carbon-climate feedback from drained soils1,7 and emphasize the importance of CH4 production in thawing permafrost on climate-relevant timescales.
Y1  - 2018
U6  - https://doi.org/10.1038/s41558-018-0095-z
SN  - 1758-678X
SN  - 1758-6798
VL  - 8
IS  - 4
SP  - 309
EP  - 312
PB  - Nature Publ. Group
CY  - London
ER  -