Fast ice

[unixronin]

The Jakobshavn glacier in Greenland drains 8% of the Greenland ice sheet.  In 1998, it approximately doubled the speed at which it is flowing into the ocean, therefore doubling the amount of fresh water it deposits into the North Atlantic.

In the last two years, the Helheim and Kangerdlugssuaq glaciers in eastern Greenland likewise doubled their speeds.  The two glaciers, 300km apart, drain 10% of Greenland's ice sheet between the two of them.  Researchers at the University of Wales in Swansea used satellite observations to determine that at their current speed of around 14km per year, the two glaciers are dumping 100 cubic kilmeters of ice into the ocean every year.

"Three outlet glaciers behaving in a similar way within a few years of each other and after a long period of stability implies both a common cause -- climate change -- and a high probability that other Greenland glaciers will respond likewise."

(Adrian Luckman, Geophysical Research Letters, vol 33, pp L03503)

Loss of the entire Greenland ice sheet would raise global sea levels by around six meters.  The good news is that current estimates indicate we'd have a couple of centuries to prepare for that.  The bad news is we'd be relying on governments to do it (which probably means the US, for one, would be totally unprepared).

Comments

[unixronin.livejournal.com]

Even with hard evidence that global warming is real, some people are saying that it's caused more by natural sources (such as volcanoes) than by human activity, so nothing we do will change that.

I know. I'm personally quite surprised by some of the people -- on my friends list, even -- who share that particular blind spot. A hundred years ago, the popular "Human activity is too small to ever affect that" belief was that there was an infinite supply of fish in the sea, and we could never fish them all out. How many major fisheries, worldwide, have collapsed due to overfishing in the last hundred years? The Grand Banks off Newfoundland ... the anchovy fishery off Peru ... most recently, the halibut fishery off Alaska has crashed ... to name but a few. And how do we respond? Mainly by telling ourselves it couldn't possibly be our fault, and by developing new, ever more efficient ways to sweep fishing areas ever cleaner of life. Japan evades whaling bans by claiming that their annual catch of several hundred whales is for "scientific purposes". (Funny how all the meat somehow ends up on the Japanese food market.)