What the study found
The study found that the rise in atmospheric methane after 2019 was explained mainly by changes in hydroxyl radicals, which are reactive molecules that help remove methane from the atmosphere. The remaining changes were linked to emissions from wetlands and inland waters.
Why the authors say this matters
The authors conclude that understanding both atmospheric chemistry and natural emissions is important for explaining recent changes in methane growth rates. The findings indicate that changes in these factors were associated with the surge and later decline in atmospheric methane growth.
What the researchers tested
The researchers used multiple atmospheric inversions, which are models that estimate emissions from atmospheric observations, together with prescribed hydroxyl radical fields from observations and models and methane atmospheric data. They examined year-on-year changes in methane growth from 2019 to 2023.
What worked and what didn't
A drop in hydroxyl radicals in 2020–2021, followed by recovery in 2022–2023, accounted for 83% of the year-to-year variation in methane growth rate. Wetland and inland water emissions increased between 2019 and 2020–2022 by 8.6 ± 2.6 TgCH4 per year, then decreased between 2022 and 2023 by 9.9 ± 3.3 TgCH4 per year.
What to keep in mind
The abstract does not describe uncertainties beyond the stated emission estimates, nor does it provide detailed limitations. It also focuses on the 2019–2023 period and on the regions highlighted in the summary.
Key points
- Atmospheric methane growth peaked at 16.2 ppb per year in 2020 and fell to 8.6 ppb per year in 2023.
- A decline in hydroxyl radicals in 2020–2021 explained 83% of the year-on-year methane growth changes.
- Wetland and inland water emissions rose from 2019 to 2020–2022, then declined from 2022 to 2023.
- Most emission changes occurred in northern tropical wetlands in Africa and Asia.
- South American wetland emissions declined, while Arctic emissions increased after 2019.
Disclosure
- Research title:
- Early 2020s methane surge linked to OH and wetland emissions
- Authors:
- P. Ciais, Yu Zhu, Y. Cai, Xin Lan, S. E. Michel, B. Zheng, Y. Zhao, D. A. Hauglustaine, X. Lin, Y. Zhang, S. Sun, X. Tian, M. Zhao, Y. Wang, J. Chang, X. Dou, Z. Liu, Robbie M. Andrew, C. A. Quinn, B. Poulter, Zutao Ouyang, W. Yuan, Kunxiaojia Yuan, Q. Zhu, F. Li, N. Pan, H. Tian, X. Yu, Gerard Rocher‐Ros, M. S. Johnson, Mengze Li, Minhui Li, Dongmei Feng, P. Raymond, Xiao Yang, J. G. Canadell, R. B. Jackson, Xueying Yu, Y. Li, M. Saunois, P. Bousquet, S. Peng
- Institutions:
- Albany State University, Albany State University, Ames Research Center, Auburn University, Boston College, Boston College, Boston College, Boston College, CEA Paris-Saclay, CEA Paris-Saclay, CEA Paris-Saclay, CEA Paris-Saclay, CEA Paris-Saclay, Centre National de la Recherche Scientifique, Centre National de la Recherche Scientifique, Centre National de la Recherche Scientifique, Centre National de la Recherche Scientifique, Centre National de la Recherche Scientifique, Chinese Academy of Sciences, Chinese Academy of Sciences, Chinese Academy of Sciences, CICERO Center for International Climate Research, Climate Central, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Commonwealth Scientific and Industrial Research Organisation, Cooperative Institute for Research in Environmental Sciences, Earth Science Institute of the Slovak Academy of Sciences, Earth Science Institute of the Slovak Academy of Sciences, Earth Science Institute of the Slovak Academy of Sciences, Earth Science Institute of the Slovak Academy of Sciences, Earth System Science Interdisciplinary Center, Forest Institute, Forest Institute, Forest Institute, Goddard Space Flight Center, Institute of Arctic and Alpine Research, Institute of Tibetan Plateau Research, Institute of Tibetan Plateau Research, Institute of Tibetan Plateau Research, Laboratoire des Sciences du Climat et de l'Environnement, Laboratoire des Sciences du Climat et de l'Environnement, Laboratoire des Sciences du Climat et de l'Environnement, Laboratoire des Sciences du Climat et de l'Environnement, Laboratoire des Sciences du Climat et de l'Environnement, Lawrence Berkeley National Laboratory, Lawrence Berkeley National Laboratory, National Oceanic and Atmospheric Administration, National University of Singapore, National University of Singapore, Ocean University of China, Southern Methodist University, Stanford University, Stanford University, Stanford University, Stanford University, Sustainability Institute, Sustainability Institute, Sustainability Institute, Sustainability Institute, Tsinghua University, Tsinghua University, Tsinghua University, Umeå University, Université de Versailles Saint-Quentin-en-Yvelines, Université de Versailles Saint-Quentin-en-Yvelines, Université de Versailles Saint-Quentin-en-Yvelines, Université de Versailles Saint-Quentin-en-Yvelines, Université de Versailles Saint-Quentin-en-Yvelines, Université Paris-Saclay, Université Paris-Saclay, Université Paris-Saclay, Université Paris-Saclay, Université Paris-Saclay, University at Albany, State University of New York, University at Albany, State University of New York, University of Cincinnati, University of Colorado Boulder, University of Colorado Boulder, University of Copenhagen, University of Houston, University of Maryland, College Park, Westlake University, Westlake University, Yale University, Yale University, Yale University, Zhejiang University
- Publication date:
- 2026-02-05
- OpenAlex record:
- View
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