Incidentally, salty sea water and clean melt water have different densities, so losing sea ice does in fact raise sea levels, though not as much
as land ice loss.
In light of these observational facts, it is unsettling that neither quantitative prediction of
future land ice loss nor credible estimation of an upper bound of future sea level are possible (IPCC, 2007).
Correcting this situation requires a predictive understanding of the processes responsible
for land ice loss.
Land ice loss — especially from northern hemisphere glaciers and the Greenland ice sheet — now exceeds thermal expansion in its contribution to rising sea level.