Abstract The hydroxyl radical (OH) determines the atmospheric lifetime of many pollutants like methane (CH4 ${text{CH} }{4}$). This study isolates climate change, air pollution control and CH4 ${text{CH} }{4}$ mitigation effects on OH concentrations ([OH]) and CH4 ${text{CH} }{4}$ lifetime, by analyzing Coupled Model Intercomparison Project Phase 6 (CMIP6) Aerosol Chemistry Model Intercomparison Project (AerChemMIP) multi‐model outputs for variants of the high‐emission SSP3‐7.0 scenario. Models agree that warming increases [OH] and decreases CH4 ${text{CH} }{4}$ lifetime, leading to a multi‐model mean CH4 ${text{CH} }{4}$ radiative forcing reduction of −0.038 Wm−2K−1 ${text{Wm} }^{-2},{mathrm{K} }^{-1}$. However, the overall trend in SSP3‐7.0 is decreasing [OH] and increasing CH4 ${text{CH} }{4}$ lifetime, confirming that changes in CH4 ${text{CH} }{4}$ and other short‐lived climate forcers (SLCFs)) dominate over climate‐related drivers. Meanwhile, air pollution controls, if not paired with CH4 ${text{CH} }{4}$ reduction, can reduce [OH] and lengthen CH4 ${text{CH} }{4}$ lifetime, potentially undermining climate efforts. In a cleaner‐air future, CH4 ${text{CH} }{4}$ mitigation will be essential to sustain higher [OH], shorten CH4 ${text{CH} }_{4}$ lifetime, and reduce its radiative forcing.