Distinct winter North Atlantic climate responses to tropical and extratropical eruptions over the last millennium in PMIP simulations and reconstructions

Abstract. Large tropical (TROP) volcanic eruptions can influence North Atlantic climate by inducing a positive shift of the North Atlantic Oscillation (NAO), typically resulting in winter warming across northern Eurasia. In contrast, Northern Hemisphere extratropical (NHET) eruptions are proposed to have opposite impacts, though uncertainties exist regarding the performance of climate models in capturing these differences. This study examines winter North Atlantic climate responses to TROP and NHET eruptions using last millennium simulations and paleoclimate reconstructions. We find distinct differences in NAO-related climate responses to TROP and NHET eruptions in both simulations and reconstructions, depending on the selection for eruption events. Notably, models employing the latest volcanic forcing dataset exhibit improved agreement with paleoclimate reconstructions. These findings highlight the critical need for improved volcanic forcing datasets, refined paleoclimate reconstructions, and robust statistical approaches to better constrain uncertainties in assessing the simulated volcanic impacts on North Atlantic climate.