Water is forming rapidly under the West Antarctic Ice Sheet. This is usually one of the signs that a glacier is undergoing accelerating disintegration. In this case, however, the scientists are quoted as saying this has been going on for a long time.
That's not exactly reassuring. The conventional understanding of the dynamics of glaciers is that they're extremely stable bodies. What this discovery could mean (and I really am past my level of knowledge, so grain of salt) is simply that our understanding was wrong -- that polar ice masses are more dynamic that we'd previously assumed. Either way, it seems unlikely that finding huge bodies of liquid water underneath the WAIS is good news.
If the WAIS disintegrates entirely (and I have no idea if that's what occurring) it would raise sea levels by 7-8 meters.
Has anybody modeled what happens to the Maritimes and BC when the sea level rises by, say, 1 meter?