Antarctic Ozone Loss Shapes Surface Cooling Pattern and Climate Sensitivity

Changes in sea surface temperature (SST) patterns have recently been recognized as a major feedback affecting the sensitivity of climate to increases in greenhouse gases ^1–3 . Over recent decades, while most of Earth’s surface warmed, the eastern tropical Pacific and Southern Ocean unexpectedly cooled. These regional SST cooling trends are not reproduced by most global climate models (GCMs) ⁴ , leading to systematic biases in estimates of global climate sensitivity ^1,2 . While Antarctic ozone depletion has been proposed as a potential driver of the cooling ⁵ , its influence has previously been considered too weak ^6,7 . Here we provide novel evidence that suggests Antarctic ozone depletion can indeed quantitatively account for this observed SST cooling. Using ~4,000 years of simulation from eight GCMs, we construct a multiple linear regression model that isolates the intrinsic relationship between Antarctic ozone and SST, capturing robust short-timescale coupling while avoiding biases from the lack of resolved ocean eddies and their long-timescale adjustments in GCMs ^8–10 . We calculate that the ozone-driven SST pattern effect strengthened the global radiative feedback by 17-21% (0.49-0.83 W m ^-2 K ^-1 ) during 1979-2000, thereby reducing effective climate sensitivity. As Antarctic ozone starts to recover ^11,12 , the stabilizing influence has begun to wane, leading to a more warming-prone climate.