On the Causes and Consequences of Recent Trends in Atmospheric Methane

Purpose of Review To investigate which processes cause the current increase in atmospheric methane in the context of future interactions between climate change, the methane cycle and policy decisions. Recent Findings There is evidence for various contributors to emission increases or reduced removal of atmospheric methane. No single process can explain the methane rise and remain consistent with available data. Reconstructions of recent changes in the methane budget do not converge as to the dominant contributor to the rise. A plausible scenario includes increasing emissions from agriculture and fossil fuels while biomass burning is reduced, with possible contributions from wetlands and a weakened sink. Summary Further studies are needed to identify contributors to the methane rise for targeted emission reductions and adaptation to changes in natural methane sources and sinks. Mitigation plans must address the methane rise and possible consequences from a climate-methane feedback.