Methane and Greenhouse gases

Methane is an air pollutant and powerful greenhouse gas. Although its sources and losses in the atmosphere are generally known, important questions remain. Are methane sources changing? If so, which ones? Is the methane sink from tropospheric OH changing and how much? How can we better quantify the impacts of methane on air quality and climate? We are addressing these and other questions.

Projected methane concentrations under four emission and climate scenarios.

Our past work has developed new projections of methane concentrations, which can account for feedbacks between changing climate and atmospheric chemistry. These projections were used in the IPCC AR5 report and the method improvements have been adopted by the MAGICC model.

We continue to advance our understanding of the tradeoffs between emissions of different greenhouse gases. The Global Warming Potential (GWP) is one common metric. It was previously thought that each kilogram of methane emission has causes as much  warming  as 24 kg of carbon dioxide (over 100 years). Our past work helped revise this consensus upward to 28. Our current work suggests it is even higher.

GWP provides a tool for comparing the climate warming impact from emissions of different gases.

Technical resources

Equations for methane radiative forcing in atmospheric chemistry models