Changes in stratification of the Southern Ocean, both through natural seasonal and interannual variability of physical conditions as well as due to climate change, are likely to have substantial impacts on carbon fluxes. South of the Polar Front, upper water column stratification is largely determined by cold water of reduced salinity residing over warmer, saltier circumpolar deep water. Warm salty deep waters derive their characteristics by mixing with the deep waters of the Atlantic, Pacific and Indian Oceans. Ventilation of deep waters in the Southern Ocean is directly dependent on the rate of exchange between surface waters and deep waters and this, in turn, is dependent on the strength of the thermohaline stratification of the upper water column. The static stability between the mixed layer and deep water is quite weak, and small perturbations of the salinity budget can upset the stability, thereby leading to a change in the rate of deep convection.
Sea ice is maintained in a metastable state through a network of negative feedbacks.
Paleoclimate records indicate that the mean position of the westerlies shifted meridionally in response to past climate changes, and it is conceivable that future climate change will likewise induce shifts in the position of the winds. Surface wind stress and Ekman divergence are tied to the zero-line of wind stress curl, so it would be expected that these features would shift with any change in the winds. The major fronts, on the other hand, are believed to be locked into their position through interaction with bottom topography. The potential impact on carbon fluxes of a change in the physical relationship between the zero-line of wind stress curl and the Antarctic Polar Front have not been investigated. In addition, regional wind patterns are known to follow the Antarctic Circumpolar Wave as it migrates around Antarctica.