Interannual variation in methane emissions from tropical wetlands triggered by repeated El Niño Southern Oscillation |
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| Authors: | Qiuan Zhu Changhui Peng Philippe Ciais Hong Jiang Jinxun Liu Philippe Bousquet Shiqin Li Jie Chang Xiuqin Fang Xiaolu Zhou Huai Chen Shirong Liu Guanghui Lin Peng Gong Meng Wang Han Wang Wenhua Xiang Jing Chen |
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| Institution: | 1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, China;2. Center of CEF/ESCER, Department of Biological Science, University of Quebec at Montreal, Montreal, QC, Canada;3. LSCE, CEA CNRS UVSQ IPSL, Université Paris Saclay, Gif sur Yvette, France;4. International Institute for Earth System Science, Nanjing University, Nanjing, China;5. Western Geographic Science Center, U.S. Geological Survey, Menlo Park, CA, USA;6. College of Life Sciences, Zhejiang University, Hangzhou, China;7. College of Earth Science and Engineering, Hohai University, Nanjing, China;8. Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China;9. Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China;10. Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing, China;11. Faculty of Life Science and Technology, Central South University of Forestry and Technology, Changsha, Hunan, China;12. Department of Geography, University of Toronto, Toronto, ON, Canada |
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| Abstract: | Methane (CH4) emissions from tropical wetlands contribute 60%–80% of global natural wetland CH4 emissions. Decreased wetland CH4 emissions can act as a negative feedback mechanism for future climate warming and vice versa. The impact of the El Niño–Southern Oscillation (ENSO) on CH4 emissions from wetlands remains poorly quantified at both regional and global scales, and El Niño events are expected to become more severe based on climate models’ projections. We use a process‐based model of global wetland CH4 emissions to investigate the impacts of the ENSO on CH4 emissions in tropical wetlands for the period from 1950 to 2012. The results show that CH4 emissions from tropical wetlands respond strongly to repeated ENSO events, with negative anomalies occurring during El Niño periods and with positive anomalies occurring during La Niña periods. An approximately 8‐month time lag was detected between tropical wetland CH4 emissions and ENSO events, which was caused by the combined time lag effects of ENSO events on precipitation and temperature over tropical wetlands. The ENSO can explain 49% of interannual variations for tropical wetland CH4 emissions. Furthermore, relative to neutral years, changes in temperature have much stronger effects on tropical wetland CH4 emissions than the changes in precipitation during ENSO periods. The occurrence of several El Niño events contributed to a lower decadal mean growth rate in atmospheric CH4 concentrations throughout the 1980s and 1990s and to stable atmospheric CH4 concentrations from 1999 to 2006, resulting in negative feedback to global warming. |
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| Keywords: | atmospheric methane El Niñ o– Southern Oscillation methane emission tropical wetlands |
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