A recent analysis of satellite data reveals that the record increase in atmospheric methane emissions between 2020 and 2022 was largely driven by increased flooding in wetlands and a slight decrease in atmospheric hydroxyl radicals (OH), which play a key role in breaking down methane. The findings, led by Zhen Qu, an assistant professor at North Carolina State University, indicate a significant spike in methane emissions during this period, compared to the slower increases observed from 2010 to 2019. Methane, a potent greenhouse gas, saw global emissions rise from around 499 teragrams (Tg) to 550 Tg between 2010 and 2019, followed by an unprecedented surge to 570–590 Tg in the following years. The research shows that while previous theories suggested the pandemic-related reduction in manmade air pollution might have been the primary cause of this surge, the reality is more complex. The team used satellite data and atmospheric models to analyze the sources of methane and OH for the period from 2010 to 2019 and compared them with data from 2020 to 2022.
Their analysis found that increased flooding of tropical wetlands was responsible for the increase in methane. Tropical regions in Asia and Africa account for 43% and 30% of methane emissions, respectively. Lowering OH levels, as a factor, accounted for only 28% of the increase. The study linked increased rainfall and wetland flooding to La Niña conditions that lasted from 2020 to early 2023. Microbial activity in wetlands, caused by decomposition anaerobic of organic matter, which increases significantly in periods of flooding, and increases in others. . Methane production The researchers emphasized the need for a deeper understanding of methane emissions to wetlands and how they respond to changes in rainfall patterns in order to develop better strategies to reduce methane’s impact on wetlands. climate change. The study, published in the Proceedings of the National Academy of Sciences, suggests that future climate models should pay more attention to wetland ecosystems as drivers of methane emissions. This work was supported by NASA and included contributions from researchers at Harvard University, the California Institute of Technology’s Jet Propulsion Laboratory, the University of Leicester and the University of Bremen.