Southern Hemisphere Volcanism Triggered Multi-year La Niñas during the Last Millennium

To explain the recent three-year La Nina event from 2020 to 2022, which has caused catastrophic weather events worldwide, Fasullo et al. (2023) demonstrated that the increase in biomass aerosol resulting from the 2019-20 Australian wildfire season could have triggered this multi-year La Nina. Here, we present compelling evidence from paleo-proxies, utilizing a substantial sample size of 26 volcanic eruptions in the Southern Hemisphere (SH), to support the hypothesis that ocean cooling in the SH can lead to a multi-year La Nina event. This research highlights the importance of focusing on the Southern Ocean, as current climate models struggle to accurately simulate the Pacific response driven by the Southern Ocean.