Divergent Responses of CH4 Emissions and Uptake to Global Change Drivers

Abstract Global changes strongly affect methane (CH 4 ) emissions and uptake. However, it is unclear how CH 4 emissions and uptake across rice paddy fields, uplands, and natural wetlands are affected by global change drivers, including nitrogen (N) addition, elevated carbon dioxide (eCO 2 ), warming (W), and precipitation (P). Here, we collected 1,250 observations of manipulated experiments from 303 publications during 1980–2020, encompassing 1,154 observations of single‐factor experiments and 96 observations of two‐paired experiments, and analyzed the effects of global change drivers on CH 4 emissions and uptake. Results showed CH 4 emissions were stimulated by eCO 2 , W, and increased P (IP). CH 4 uptake was inhibited by N and IP but significantly enhanced by W and decreased P. The combined effects of the four global change drivers significantly inhibited CH 4 uptake (−9[−12, −6] %) and stimulated CH 4 emissions (13[7, 19] %). Two‐factor interactions significantly reduced CH 4 emissions (−15[−27, −1] %) and insignificantly reduced uptake (−10[−19, 0] %). The interactive effects of any two global change drivers were mostly antagonistic. Random forest analysis indicated that the important factors affecting the responses of CH 4 emissions or uptake to different global change drivers varied. The structural equation model confirmed that climate, soil properties, and wetness index consistently played a remarkable role in regulating the responses of CH 4 emissions and uptake to global change drivers. This synthesis highlights an urgent need to consider the individual and interactive effects of multiple global change drivers on CH 4 emissions and uptake for a better understanding of the methane‐climate feedback.