Clean air policy makes methane harder to control due to longer lifetime

Achieving the Paris Agreement’s 1.5°C target necessitates reversing the rise in atmospheric concentrations of methane (CH₄), which is a greenhouse gas that is more radiatively potent than carbon dioxide, and that possesses a considerably shorter lifetime. Future reductions in pollutants like nitrogen oxides for air quality improvement are anticipated, with a side effect of potentially extending the lifetime of CH₄. However, at present the antagonism between air quality improvements and climate change response with respect to CH₄ lifetime is not being prominently addressed. Utilizing the GEOS-Chem model, we assessed CH₄ lifetime sensitivity to pollutant emissions. Applying this sensitivity to the OSCAR box model, we simulated future CH₄ dynamics, revealing that pollutant reduction in SSP1-26 compared to SSP2-45 could offset nearly 20% of CH₄ abatement efforts. Our study highlights the pollution abatement penalty in controlling atmospheric CH₄ concentrations, suggesting the need for escalated endeavors to combat climate change.