A new study shows that during the last two deglaciations, i.e., the transition from an ice age to the warm interglacial periods, meltwater from the Antarctic ice sheet intensified stratification in the Southern Ocean. The results highlight the key role of the Antarctic ice sheet on ocean circulation and the regulation of the global climate. The study was led by François Fripiat, a researcher at the Max Planck Institute for Chemistry and the Université Libre de Bruxelles, and was conducted in collaboration with researchers from Princeton University and the Alfred Wegener Institute. It is published in the Proceedings of the National Academy of Sciences.