Changes in atmospheric methane abundance have implications for both chemistry and climate, as methane is both a strong greenhouse gas and an important precursor for tropospheric ozone. The global network of methane surface observations over the past 3-4 decades indicates that methane went through a period of rapid growth from the 1980s to 1990s, nearly stabilized from 1999 to 2006, and then renewed its rapid growth.
Studies of the drivers of observed changes in methane trends and variability have focused on the contributions from changes in methane sources and sinks. In a recent paper, led by AOS Postdoc Jian He, the authors applied a prototype version of new generation Geophysical Fluid Dynamics Laboratory chemistry-climate model, AM4.1 (Zhao et al., 2018a, b; Horowitz et al., 2020) with an improved representation of methane, to explore the contributions of methane sources and sinks to its observed trends and variability. GFDL's Vaishali Naik and Larry Horowitz, an AOS faculty member, are among the study's co-authors. The paper was published in Atmospheric Chemistry and Physics.