Biogeochemical feedback effects on future wetland methane emissions and implications for global mitigation

Natural wetlands account for one-third of global methane (CH4) emissions and so profoundly influence climate. However, existing estimates of future changes in CH4 usually neglect feedbacks associated with global biogeochemical cycles. Here, we employ data-driven approaches to estimate both current and future wetland emissions that consider the effects of changing meteorology and biogeochemical feedbacks arising from sulfate deposition and CO2 fertilization. We report intensified wetland emissions from 2000-2100, with biogeochemical effects explaining 30% of emissions growth by 2100. Our results suggest that 8-15% more aggressive cuts to anthropogenic methane emissions are needed if we are to stay within the Paris Agreement guardrails of 1.5°C warming.