Near-future rocket launches could slow ozone recovery

Rocket emissions damage the stratospheric ozone layer, which protects life from harmful solar radiation. To understand if significant ozone losses could occur as the launch industry grows, we examine two scenarios of industry aspirations. Our ‘ambitious’ scenario (2,040 launches/year) leads to a -0.29% depletion in annual-mean, near-global total column ozone, relative to a simulation with no rocket launches. Antarctic springtime ozone decreases by 3.9%. Our ‘conservative’ scenario (884 launches/year) leads to a -0.17% annual depletion; current licensing rates suggest this scenario may be exceeded sooner than 2030. Ozone losses are mostly driven by the reactive chlorine produced from solid rocket motor propellant, and black carbon which is emitted from most propellants in contemporary use. The ozone layer is slowly healing from the effects of anthropogenic CFCs, yet ozone abundances are still 2% lower than those measured prior to the onset of CFC-induced ozone depletion. Our results demonstrate that ongoing and frequent rocket launches could delay ozone recovery. Action is needed now to ensure that future growth of the launch industry and ozone protection are mutually sustainable.