Modelling the Response of the West Antarctic Ice Sheet to a Climatic Warming

Increasing carbon dioxide and other trace gases in the atmosphere over the next few centuries may lead to important consequences in regard to climatic change. One of the most severe consequences alluded to is the possibility of a rapid rise in sea level resulting primarily from increased melting of the Antarctic Ice Sheet — particularly from West Antarctica where much of the ice is currently grounded well below sea level.The present generation of coupled atmosphere-ocean general circulation models still have problems in simulating the present situation, but nevertheless have provided useful information on the possible decrease in the Antarctic sea-ice cover and the increase in ocean temperatures over time as a result of the warming following the increased atmospheric carbon dioxide concentration. This information has been used to analyse the extreme likely increases in the melt rates of the Antarctic ice shelves and the resulting increased strain rates which could then occur near the grounding lines.A hierarchy of ice-sheet modelling studies has been carried out covering the fast-flowing ice streams, the ice sheet thermal regime and the whole Antarctic at a coarser resolution. The range of consequences likely for ice loss and sea-level rise are computed in detail for the next 500 years, and in less detail for several thousand years hence.It is concluded that the effects for sea-level change could be substantial but of a magnitude (up to 1 m in 500 years and 3.5 m in 1000 years) and a rate of change (maximum of 0.6 m/100 years) that could be manageable if adequate monitoring and planning are carried out.