GIS tools combined with good Digital elevation Model could give a quick estimate on the inundation areas due to sealevel rise. One such application of ours is documented here at http://drs.nio.org/drs/handle/2264/4420
For more resolution in the inundation estimates better hydrodynamic models can also be used.
and most land is lost as a result of storm surge erosion. This dominates over the systematic rise of sea level. Louisiana in the US is a good example of erosive forces at work