Emerging role of wetland methane emissions in driving 21st century climate change.

Autor: Zhang Z; Dynamic Macroecology, Swiss Federal Research Institute WSL, Birmensdorf 8903, Switzerland; yuisheng@gmail.com.; Institute on Ecosystems and Department of Ecology, Montana State University, Bozeman, MT 59717.; Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China., Zimmermann NE; Dynamic Macroecology, Swiss Federal Research Institute WSL, Birmensdorf 8903, Switzerland.; Department of Environmental System Science, ETH Zürich, Zürich 8092, Switzerland., Stenke A; Department of Environmental System Science, ETH Zürich, Zürich 8092, Switzerland., Li X; Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China., Hodson EL; Office of Energy Policy and Systems Analysis, US Department of Energy, Washington, DC 20585., Zhu G; Key Laboratory of Western China's Environmental Systems, Lanzhou University, Lanzhou 730000, China., Huang C; Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China., Poulter B; Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.; Biospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20770.
Jazyk: angličtina
Zdroj: Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2017 Sep 05; Vol. 114 (36), pp. 9647-9652. Date of Electronic Publication: 2017 Aug 21.
DOI: 10.1073/pnas.1618765114
Abstrakt: Wetland methane (CH 4 ) emissions are the largest natural source in the global CH 4 budget, contributing to roughly one third of total natural and anthropogenic emissions. As the second most important anthropogenic greenhouse gas in the atmosphere after CO 2 , CH 4 is strongly associated with climate feedbacks. However, due to the paucity of data, wetland CH 4 feedbacks were not fully assessed in the Intergovernmental Panel on Climate Change Fifth Assessment Report. The degree to which future expansion of wetlands and CH 4 emissions will evolve and consequently drive climate feedbacks is thus a question of major concern. Here we present an ensemble estimate of wetland CH 4 emissions driven by 38 general circulation models for the 21st century. We find that climate change-induced increases in boreal wetland extent and temperature-driven increases in tropical CH 4 emissions will dominate anthropogenic CH 4 emissions by 38 to 56% toward the end of the 21st century under the Representative Concentration Pathway (RCP2.6). Depending on scenarios, wetland CH 4 feedbacks translate to an increase in additional global mean radiative forcing of 0.04 W·m -2 to 0.19 W·m -2 by the end of the 21st century. Under the "worst-case" RCP8.5 scenario, with no climate mitigation, boreal CH 4 emissions are enhanced by 18.05 Tg to 41.69 Tg, due to thawing of inundated areas during the cold season (December to May) and rising temperature, while tropical CH 4 emissions accelerate with a total increment of 48.36 Tg to 87.37 Tg by 2099. Our results suggest that climate mitigation policies must consider mitigation of wetland CH 4 feedbacks to maintain average global warming below 2 °C.
Competing Interests: The authors declare no conflict of interest.
Databáze: MEDLINE
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