Recent sea surface temperature trends hinder Antarctic stratospheric ozone recovery

Recent reports on anomalously large ozone holes imply the uncertainty of the Antarctic ozone recovery. This study demonstrates that the sea surface temperature trends during this century hinder this recovery, despite declining ozone-depleting substances. Observations show a significant recovery of the polar mean total column ozone in September during 2000-2021, contrasted by robust ozone loss in the South Pacific middle stratosphere during October-November. Numerical experiments reveal that ozone-depleting substance reduction alone drives significant Antarctic ozone recovery throughout austral spring. However, superimposing observed sea surface temperature linear increments causes significant stratospheric ozone decreases over the South Pacific in October-November and reduces the spring mean recovery by approximately 46%. Both reanalysis data and simulations indicate that sea surface temperature forcing weakens Antarctic stratospheric planetary wave activity, causing regional cooling and nitric acid loss. These changes increase the ratios between the active halogens and the halogen reservoirs, thereby promoting ozone depletion. Recent sea surface temperature trends weaken Antarctic stratospheric planetary wave activity, reducing atmospheric nitric acid and promoting ozone depletion, according to analyses of observations, reanalysis data, and model simulations.