I was reading an article on the accellerated melting of the icecaps and a simple, possibly wrong, confusion popped into my head. There have been a lot of doomsday prophecies of massive flooding, but don't the icecaps displace all of the water that they sit in? Would the melting of the caps really raise the water level at all?
Responses:
Dr. Egon Spengler
That is in fact true of the Arctic ice cap, which floats on water. For various reasons, the only ice that is really worrisome is West Antarctica. It is unstable, and the local geology is unusual in that most of the land is below sea level, and in fact the land gets lower as your travel inland. The ice shelves off the coast there are closely monitored, not because their melting would raise sea levels, but because they serve as a barrier for the inland ice which would otherwise take its place and eventually melt. That ice is on land, and that ice is heavy, and if it moves to the ocean it starts to melt faster. And once it starts to float, it's all going to displace water. And since the land it was on is underwater, there's now less land for ice to be on. Of course, the idea that global warming would cause that ice to thin is open to debate; there is currently very little snow near the south pole; it's simply too cold. Warmer temperatures could in fact cause the ice to thicken due to increased snowfall, but it seems the less likely outcome given current data.
Dr. Egon Spengler
Even in that case, don't relax too soon. The real problem is that water, like most other things, expands when heated. The thermal expansion of water is low, but there's a lot of water out there. That expansion alone should be enough to flood a good portion of your beachfront property.
Dr. Egon Spengler
However, 'flooding due to melting of the polar icecaps' is easier for the average person to wrap their minds around than 'flooding due to the thermal expansion of water.'
And it also sounds better as a dire prediction of doom.
