2024-09-24 ノースカロライナ州立大学(NCState)
＜関連情報＞
- https://news.ncsu.edu/2024/09/atmospheric-methane-increase-during-pandemic-due-primarily-to-wetland-flooding/
- https://www.pnas.org/doi/10.1073/pnas.2402730121
2010-2022年の衛星観測の逆モデリングにより、2020-2022年のメタン急増は湿潤熱帯の氾濫がもたらしたことが示される Inverse modeling of 2010–2022 satellite observations shows that inundation of the wet tropics drove the 2020–2022 methane surge
Zhen Qu, Daniel J. Jacob, A. Anthony Bloom, +2, and Hartmut Boesch
Proceedings of the National Academy of Sciences Published:September 24, 2024
DOI:https://doi.org/10.1073/pnas.2402730121
Significance
Atmospheric methane growth has accelerated over the past decade, including record-high increases in 2020–2022. We show that the decadal growth has been driven by the wet tropics while methane emissions at northern mid-latitudes have decreased. We attribute the 2020–2022 surge to large-scale inundation in Africa and Equatorial Asia associated with La Niña conditions and consistent with terrestrial water storage data. The dominance of the wet tropics in driving the methane trend has important implications for finding a pathway to decrease atmospheric methane and mitigate near-term climate change.
Abstract
Atmospheric methane concentrations rose rapidly over the past decade and surged in 2020–2022 but the causes have been unclear. We find from inverse analysis of GOSAT satellite observations that emissions from the wet tropics drove the 2010–2019 increase and the subsequent 2020–2022 surge, while emissions from northern mid-latitudes decreased. The 2020–2022 surge is principally contributed by emissions in Equatorial Asia (43%) and Africa (30%). Wetlands are the major drivers of the 2020–2022 emission increases in Africa and Equatorial Asia because of tropical inundation associated with La Niña conditions, consistent with trends in the GRACE terrestrial water storage data. In contrast, emissions from major anthropogenic emitters such as the United States, Russia, and China are relatively flat over 2010–2022. Concentrations of tropospheric OH (the main methane sink) show no long-term trend over 2010–2022 but a decrease over 2020–2022 that contributed to the methane surge.
