Why is the Southern Ocean (SO) warming so much more slowly than the rest of the world’s oceans? It seems that it’s due to wind-driven upwelling of old, deep waters around Antarctica. These upwelled waters were last in contact with the atmosphere hundreds of years ago, at least, meaning that they have yet to feel the effects of global warming. Once these waters reach the SO surface, they’re pushed equatorward by the winds, carrying heat they receive from rising greenhouse gases with them, away from the continent.
Armour KC, J Marshall, J Scott, A Donohoe and ER Newsom (2016) Southern Ocean warming delayed by circumpolar upwelling and equatorward transport, Nature Geoscience, doi: 10.1038/ngeo2731