Methane emissions have been increasing rapidly, at a faster rate than any other substantial climate driver during the past few years, making it especially pressing to change the trajectory for this powerful greenhouse gas. Not only does this gas lead to large amounts of near-term warming, but methane creates tropospheric ozone and recent studies find larger health and agricultural damages from methane than previously believed. Nevertheless, efforts to reduce methane have clearly been inadequate thus far given the rapid growth, and likely this is in part because there is inadequate awareness of the multiple benefits of emissions reductions.
The Global Methane Assessment is working to better characterize the benefits of methane reductions with state-of-the-art modeling, and to document the multiple benefits that could be realized through methane reductions with examples including near-term technical and behavioral mitigation policies. In order to better quantify the benefits of methane mitigation and uncertainties associated with such quantification, this work looks at the response to emissions across a range of impacts using a range of models. The modeling examines the worldwide impact of methane emissions, which have the same impact regardless of emission location owing to methane’s relatively long atmospheric residence time. Impacts include the response of ozone, temperature and precipitation. Full atmospheric composition-climate models are required to capture the response of ozone, which is quite inhomogeneous, as well as climate responses.