Abstract

Without stringent reductions in emission of greenhouse gases in the coming years, an exceedance of the 1.5C temperature limit would become increasingly likely. This has given rise to so-called temperature overshoot scenarios, in which the global mean surface air temperature increase above pre-industrial levels exceeds a certain limit, i.e. 1.5C, before bringing temperatures back below that level. Despite their prominence in the climate mitigation literature, the implications of an overshoot for local climate impacts is still understudied. Here we present a comprehensive analysis of implications of an overshoot for regional temperature and precipitation changes as well as climate extremes indices. Based on a multi-model comparison from the Coupled Model Intercomparison Project (CMIP6) we find that temperature changes are largely reversible in most regions, but also report significant land-ocean and latitudinal differences after an overshoot. For precipitation, the emergent picture is less clear. For regions where significant changes in precipitation can be identified, a reversibility of those changes is the exception, with most regions experiencing increased drying or wetting after an overshoot. This effect is even more pronounced for extreme precipitation. Taken together, our results indicate that even under a reversal of global mean temperature increase, regional climate changes may only be partially reversible, if at all. We thus provide further evidence that overshooting of a warming level implies irreversible changes.