Global Response and Mechanism of Methane Cycling in Wetlands Under Elevated Atmospheric CO and Warming.

Wen Xing, Yuxin Huo, Jingjing Peng, Chunwu Zhu, Yong-Guan Zhu, Siyu Chen, Shuiqing Chen, Ke-Qing Xiao

Journal: Global change biology 2025;31(7):e70325

PMID: 40616311

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Abstract

Wetland is one of the most significant sources of methane (CH). Although global warming and elevated atmospheric carbon dioxide concentrations (eCO) are expected to affect the CH cycle, the response of CH emission in natural wetland and paddy has been observed to be inconsistent. This variation is likely due to the complex interactions among soil, plant, and microbial processes that regulate CH dynamics, leaving the underlying mechanisms across global studies unknown. Here, we conducted a meta-analysis to elucidate the effects of warming, eCO, and their co-effects on CH cycling in wetland. Our results demonstrate that eCO significantly increased CH emission in paddy (18.57%) but had no significant effect on that in natural wetland, attributed to eCO-induced increase in belowground biomass and methane production potential in paddy. Conversely, warming promoted CH emission in natural wetland (26.71%) but had no substantial impact on CH in paddy. This difference is due to the lower mean annual temperature in natural wetland compared with paddy, where warming promotes plant growth and methanogen activity. Notably, the combined effects of eCO and warming on paddy CH emission were markedly greater than their individual effects, with a synergistic increase of 44.63%. Furthermore, the impact of eCO on CH emitted by natural wetland was enhanced with time, likely due to different extent of plant-induced priming effect and progressive nitrogen limitation, while CH emissions from paddies declined greatly with time. Our findings emphasize the pivotal role of wetlands in the global methane cycle and highlight the complex responses of CH emissions to climate changes.

Address: State Key Laboratory of Regional and Urban Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.; State Key Laboratory of Nutrient Use and Management, Key Laboratory of Plant-Soil Interactions, College of Resources and Environmental Sciences, Ministry of Education, National Academy of Agriculture Green Development, China Agricultural University, Beijing, China.; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.; State Key Laboratory of Regional and Urban Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.; State Key Laboratory of Regional and Urban Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.; Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China.; Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.; State Key Laboratory of Regional and Urban Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.; Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.

DOI: 10.1111/gcb.70325

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MeSH Terms: Wetlands, Methane, Carbon Dioxide, Global Warming, Climate Change, Oryza, Atmosphere