Assessing the potential benefits of methane oxidation technologies using a concentration-based framework

Lowering the atmospheric methane concentration is critical to reducing short-term global warming because of methane’s high radiative forcing and relatively short lifetime. Methane could be destroyed at its emissions sources or removed from the atmosphere by oxidizing it to carbon dioxide and water vapor, greatly lowering the warming effect. Here we provide, to the best of our knowledge, the first estimate of the amount of methane that is emitted at a given concentration. We use this to assess the potential benefits (global temperature, air quality, and economic) of various technologies that could oxidize methane above specific concentration thresholds. We estimate that global mean surface temperature could be reduced by 0.2 °C ± 0.1 °C by continuously oxidizing all anthropogenic methane emitted above 1000 parts per million (the lowest concentration addressable with current commercial technologies). Continuously oxidizing all methane currently emitted above ten parts per million could cause 0.4 °C ± 0.2 °C of cooling. For the economic benefit of removing atmospheric methane to outweigh the associated energy cost, we show that reactors that use heat to oxidize methane must operate at most 3 °C ± 2 °C above ambient temperature while those that use light must convert at least 9% ± 8% of photons into oxidized methane molecules. Our framework can be used by scientists, engineers, and policymakers to better understand the connections between methane sources, including their emission rates and concentrations, and the technologies that can oxidize those emissions. © 2023 The Author(s). Published by IOP Publishing Ltd.