Methane production as key to the greenhouse gas budget of thawing permafrost
- 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 conditionsPermafrost 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.…
Author details: | Christian KnoblauchORCiDGND, Christian BeerORCiD, Susanne LiebnerORCiDGND, Mikhail N. GrigorievORCiDGND, Eva-Maria Pfeiffer |
---|---|
DOI: | https://doi.org/10.1038/s41558-018-0095-z |
ISSN: | 1758-678X |
ISSN: | 1758-6798 |
Title of parent work (English): | Nature climate change |
Publisher: | Nature Publ. Group |
Place of publishing: | London |
Publication type: | Article |
Language: | English |
Date of first publication: | 2018/03/19 |
Publication year: | 2018 |
Release date: | 2021/12/15 |
Volume: | 8 |
Issue: | 4 |
Number of pages: | 6 |
First page: | 309 |
Last Page: | 312 |
Funding institution: | Research Foundation [EXC177]; CarboPerm project - German Ministry for Research and Education [03G0836A]; Helmholtz GemeinschaftHelmholtz Association [VH-NG-919] |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Biochemie und Biologie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie |
Peer review: | Referiert |
Publishing method: | Open Access / Green Open-Access |