EOCENE-OLIGOCENE TRANSITION AND EARLY ATLANTIC MERIDIONAL OVERTURNING CIRCULATION
The Eocene-Oligocene Transition (EOT) around 33.7 million years ago (Ma) is arguably one of the most puzzling climate events during the Cenozoic. The EOT is marked by substantial climatic and oceanic reorganizations as demonstrated in numerous studies, yet the chain of processes or associated driving mechanisms remain controversial. The two competing hypotheses, global atmospheric CO2 drawdown and Southern Ocean gateway opening, remain as the ultimate EOT cause. Recent studies have focused on the early Atlantic Meridional Overturning Circulation (AMOC) development and a potential role it played for the EOT. Here we address this critical climate event with updated sea surface temperature (SST), atmospheric CO2, and early AMOC records. The unexpected SST evolution in the North Atlantic Ocean and early AMOC development will largely modify our current view.