Geophys. Res. Lett. 35, L17705 (2008)

Credit: istockphoto

Melting of the Antarctic ice-sheet could moderate warming in the Southern Hemisphere, by as much as 10°C locally, shows a new study.

The study led by Didier Swingedouw of the Université Catholique de Louvain, Belgium uses a three-dimensional Earth system model with well-characterised polar ice sheets to look at the effect of Antarctic ice-sheet melting over coming centuries and millennia. The authors use a scenario whereby atmospheric carbon dioxide concentrations increase by one per cent a year until they reach four times their initial value and then remain unchanged for 3,000 years. Under such conditions, the model shows that a shallow halocline forms in the Southern Ocean, where colder, lower-salinity surface water would limit the retreat of sea-ice cover. The white reflective surface of the sea ice is important in reducing local warming. In addition, the simulations show that ice-sheet melt water can limit the formation of Antarctic bottom water, with implications for global ocean circulation and consequently climate and sea level.

The authors stress that the results are not intended as a forecast, but to provide insights on how climate would be affected by Antarctic ice-sheet melting for a given warming scenario.