it's not "underwater ice", it's "ice sitting on soil that is below sea level". The ice sheet is thick enough to be significantly above water level, but it's esp

it's not "underwater ice", it's "ice sitting on soil that is below sea level". The ice sheet is thick enough to be significantly above water level, but it's especially vulnerable to temperature increases in the ocean, since ocean water can start flowing under the ice and melt it from below.