The masses of ice covering Greenland and Antarctica are actually continental glaciers, the same sort of glaciers that covered much of North America during the Ice Age. They are more properly called ice sheets. Ice caps are smaller, non-valley glaciers. They are found in Iceland, Baffin Island, and other Arctic islands. When scientists argue over melting ice and rising sea level, they usually mean not only the Antarctic and Greenland ice sheets, but also the ice caps and valley glaciers, which are found in such places as Alaska and Norway.
Researchers do agree on some predictions.
A report released in March estimates that sea level will rise half a meter around the world in the next 100 years, covering tens of thousands of square kilometers of land with water. This rise in sea level will be due, in some part, to global warming and the melting of some of Earth's glaciers. What researchers cannot agree on is whether or not the rate of sea level increase is accelerating. Listen to National Public Radio's Talk of the Nation edition on Effects of Rising Sea Level. Sometimes it is even difficult to know for sure that sea level is rising at all.