Seasonal El Niño-Southern Oscillation and Indian Ocean Dipole Dependencies of Methane Emissions From Wetlands

Wetlands are a significant natural source of methane (CH4), and their emissions are highly sensitive to climatic variability. This study investigated the impact of El Ni & ntilde;o-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) events on wetland CH4 emission anomalies based on a model simulation data set from 1980 to 2022. Results showed El Ni & ntilde;o reduced CH4 emission anomalies, whereas La Ni & ntilde;a increased them. Both ENSO and IOD phases greatly altered climatic variables, which in turn affected CH4 emission anomalies. The global mean sensitivities of CH4 emission anomalies to ENSO and IOD were -0.17 and -0.08 mg CH4 m-2 month-1, respectively, which exhibited pronounced temporal and spatial variability, mainly driven by soil moisture and temperature. This study underscored the pronounced temporal and spatial variability of CH4 emission anomalies under ENSO and IOD phases, which would improve the accuracy of predictive CH4 models and inform strategies for mitigating climate change.