Changes in ocean hydrology have been observed over the last 40 years, and paleoclimate data suggest that changes in ocean circulation have played an important role in climatic changes of the recent geological past. Rapid and large amplitude changes in both ocean circulation and climate have occurred repeatedly and in concert during the last glacial period. It is an important question whether similar changes could also occur in the foreseeable future, in particular in response to anthropogenic forcing.

The aim of the session is to bring together physical oceanographers, paleoceanographers, and modelers, to improve understanding of past, present, and future changes in ocean hydrology and circulation, both in their mean state and in their natural variability modes (time scales ranging from several decades to several millennia). Topics of particular interest are observations and proxy data of past and current changes, and modeling studies dealing with the sensitivity and stability properties of the thermohaline circulation and its possible future.