Wednesday, March 26, 2008

Cracks In The Ice

Al Gore warned us in An Inconvenient Truth about this:

March 25, 2008—New satellite images reveal what scientists call the "runaway" collapse of an enormous ice shelf in Antarctica as the result of global warming.

The chunk of coastal ice was some 160 square miles (415 square kilometers) in area—about seven times the size of Manhattan.

The shelf's rapid collapse began on February 28 (see image sequence at top right), sending a giant swath of broken ice into the sea—as seen in the bottom image, which shows a 2-mile-wide (3.2-kilometer-wide) area.
Keep in mind that it's nearly "autumn" in the southern hemisphere, and so there might be some firming up of this ice before long.

However, ice shelfs in the Antarctic are like dams, and when a dam breaks, it doesn't take much to encourage the stuff behind the dam to fall too.

The collapse and calving of the Wilkins ice shelf won't raise sea levels. It was already on the water, so it's specific gravity was accounted for. But the stuff behind it, that's all on land, and would add to sea levels quickly, like dropping an ice cube into a full glass of water.

Worse for us, of course, is the fact that ice doesn't move as rapidly as liquid water. In the year when the land ice slips into the ocean, people will have forgotten this event, and what triggered the next collapse. This is one large difficulty about explaining the global climate crisis to people who's attention span is now shorter than an MTV video.

It's going to be a long hot summer.