The “methane feedback” is an interaction between methane concentrations and atmospheric chemistry that amplifies changes in methane emissions by almost 40%. As a result, the methane feedback is responsible for nearly 0.3 W/m² of radiative forcing. In a paper recently published in JAMES, we provide the first detailed assessment of how the feedback strength depends on climate and ozone precursor emissions. We show that the conventional view of the methane feedback, as a simple result of OH loss controlled by CH4, is only partially correct. The feedback strength also depends on autocatalytic OH production and OH buffering by atmospheric VOCs.
For those conducting research in the field, the paper also reviews the mathematical and chemical basis for understanding the feedback and summarizes practical formulas needed to quantify it.