Impacts and effects of ocean warming on Antarctic ecosystems and species

The Antarctic marine ecosystem is strongly dependent on the regional circulation and climate of the ocean, and is important because of its role in the global carbon cycle, fisheries, and for the conservation of many of the globe's iconic marine mammals, penguins and flying seabirds. The oceans around Antarctica are changing rapidly, with average rates of warming and freshening that greatly exceed the global mean, but with complex regional structure to the changes. The prognosis for the region is difficult to assess because the coupled climate models of the sort used by the IPCC perform poorly at simulating the Southern Ocean, including the sea ice environment. Nevertheless, the coupled climate models consistently predict a warming of the Southern Ocean in coming decades, along with a freshening of upper-layer water masses, and a shallowing of the surface mixed layers. The knowledge that is available points to a changing system that will have consequences for species and the ecosystems as a whole, largely resulting in a contraction of this ecosystem to higher latitudes. Management bodies in the region will need to adapt management practices to a changing future. A critical gap in capability is sustained circumpolar observations needed to assess current and future ecosystem states.