Sea ice, as the glacial cycles' climate switch, and interhemispheric thermohaline teleconnections

A box model combining the different physical components of the coupled ocean, atmosphere, sea-ice and land-ice climate system is used to study the possible role of sea ice in the glacial-interglacial oscillations. In this paper we investigate the teleconnection between the two hemispheres, and suggest a mechanism which can explain the observed Southern Ocean sea-ice variability during glacial-interglacial cycles. The teleconnection mechanism involves changes in the temperature of the water transported from the Northern to the Southern Hemisphere by the thermohaline circulation (THC), rather than the amplitude of the THC as has often been suggested. The sequence of events proposed by this model indicates that it would be especially interesting to obtain accurate information on the relative timing of sea-ice and land-ice variations. Fuller general circulation models and new sea-ice proxy data are needed to quantify the relative role of the proposed teleconnection mechanism.