Reduced mid-latitude El Niño-related precipitation due to southern ocean warming under abrupt CO₂ change scenarios

Climate recovery has predominantly been examined through socio-economic lenses. Using two Earth system models, we demonstrate that, despite an immediate return to pre-industrial CO₂ levels, local climates exhibit significantly delayed recovery relative to the global mean. The Northern Hemisphere (NH) experiences persistent cooling, while the Southern Hemisphere (SH) shows sustained warming, accompanied by weakened El Niño-induced mid-latitude precipitation. These regional disparities are driven by ocean–sea ice–atmosphere interactions, notably the inhibition of sea ice recovery in the Southern Ocean due to retained sea surface salinity, which suppresses the sea ice–albedo feedback. In the tropics, cooler SSTs and easterly anomalies weaken El Niño events, reducing associated atmospheric teleconnections and mid-latitude precipitation by up to 30%. These results highlight that anthropogenic climate forcing can leave persistent regional imprints, particularly in the mid-latitudes, even after CO₂ concentrations are restored to pre-industrial levels.