Robust Inter‐Hemispheric Asymmetry in the Response to Symmetric Volcanic Forcing in Model Large Ensembles

Abstract

Abstract The climate response to volcanic eruptions in the twentieth century is difficult to separate from the influence of anthropogenic greenhouse gas forcing and internal variability. Here, we make use of recently available large ensembles of Earth‐system model simulations to better understand the forced climate response to contemporary volcanic eruptions. While the Pinatubo eruption in June 1991 resulted in approximately symmetric forcing between the Northern and Southern Hemispheres, the ensemble‐mean simulated temperature and sea ice responses it produces are asymmetric. The strongest cooling and sea ice expansion occur in the Arctic, while the responses in the Antarctic are weak. The damped high‐latitude Southern Hemisphere response to volcanic forcing is analogous to the fast response to increased greenhouse gas concentrations, despite the differing physical nature of the forcing. We find that Arctic cooling in response to a Pinatubo‐scale eruption may not occur due to the high internal variability in that region