J. Clim. http://doi.org/w3d (2014)

The Southern Ocean accounts for 30% of the global ocean and is an important region for upwelling as well as deep-water formation. Upwelled waters, which are cold and low in CO2 (owing to their extended isolation from the surface) absorb heat and carbon from the atmosphere. It is thus important to understand the role of the Southern Ocean in the global carbon cycle.

Thomas Frölicher of ETH Zurich, Switzerland, and Princeton University, USA, and colleagues investigate the role of the ocean, and in particular the Southern Ocean, in uptake, storage and transport of anthropogenic carbon and heat from 1861 to 2005. They use 19 coupled climate models from the Coupled Model Intercomparison Project Phase 5 and observations over the period.

Model results show that for the historical period studied, 43% of the ocean uptake of anthropogenic CO2 and 75% of heat uptake occurs in the Southern Ocean, which is all areas south of 30° S. Observational data indicates that the models are able to replicate ocean heat content trends, but underestimate carbon storage.