Global responses of wetland methane emissions to extreme temperature and precipitation

As global warming continues, events of extreme heat or heavy precipitation will become more frequent, while events of extreme cold will become less so. How wetlands around the globe will react to these extreme events is unclear yet critical, because they are among the greatest natural sources of methane. Here we use seven indices of extreme climate and the rate of methane emission from global wetlands during 2000-2019 simulated by 12 published models as input data. Our analyses suggest that extreme cold (particularly extreme low temperatures) inhibits methane emissions from wetlands, whereas extreme heat (particularly extreme high temperatures) accelerates methane emission from wetland(WME). Our results also suggest that daily precipitation > 10 mm accelerates emission from wetlands, while much higher daily precipitation levels can slow emission. The correlation of extreme high temperature and precipitation with rate of methane emission became stronger during the study period, while the correlation between extreme low temperature and emission rate became weaker.