Different Dynamics May Be Driving "Unusual" Glacial Movements In Greenland, Antarctica - WP

[hatrack]

Some of the largest glaciers in Antarctica and Greenland are moving in unusual ways and are losing increased amounts of ice to the sea, researchers said yesterday. Although the changes in Greenland appear to be related to global warming, it remains unclear what is causing the glaciers of frigid Antarctica and their "ice streams" to lose ice to the ocean in recent years, the researchers said.

"In Greenland we know there is melting associated with the ice loss, but in Antarctica we don't really know why it's happening," said Duncan Wingham, an author of the review released today in Science magazine. "With so much of the world's ice captured in Antarctica, just the fact that we don't know why this is happening is a cause of some concern."

The Antarctic ice loss, which Wingham said is not caused by melting but rather by the pushing of ice streams into the ocean by several glaciers in the west of the continent, has picked up speed in recent years. But Wingham said that because researchers did not have good measures of the depth of the Antarctic ice shelf until about 10 years ago, scientists do not know whether this is a natural variation or a result of human activity. Complicating the situation for those studying Antarctica, some parts of the continent are gaining ice depth through snowfall while temperatures on the tip of the Antarctic peninsula, the continent's closest point to South America, are rising faster than almost anywhere else on the planet. The surprisingly fast-moving glaciers are largely on the West Antarctic ice sheet. (ed. - emphasis added)

EDIT

In Greenland, glaciers appear to be moving more quickly to sea because melting ice has allowed the sheet to slide more easily over the rock and dirt below. In Antarctica, the loss is believed to be associated with the breaking off into seawater of ice deep under the ice sheet with little-understood internal dynamics that put increased pressure on the massive ice streams.

EDIT

http://www.washingtonpost.com/wp-dyn/content/article/2007/03/15/AR2007031501063.html

[kestrel91316]

1. Everybody stay OFF the beaches, cause a tsumani is gonna

happen when that ice all slides off into the water in the course of a few hours.

[petronius]

2. Well, damn - I just finished packing the picnic basket

:(

I guess we can go to the mountains for the weekend, instead...

[happyslug]

3. Don't make to much of a joke, if the WAIS breaks it will within the next 30 days.

The West Antarctic Ice Sheet (WAIS) is at its Minimum size around this time of the year, the Southern Hemisphere start of Autumn. Soon do to the shorting days, the WAIS will start to expand. This expansion will straighten the WAIS till next spring.

At this time of year ice melts and becomes water and sinks into cracks in the ice. Overnight the water -refreezes and expands, putting pressure on the ice which may cause it to break. Once the break starts it may be impossible to stop causing the whole WAIS to break off its mooring sand float right into the Southern Ocean.

The time period for this is March to the middle of April. If nothing happens by April 15th, we will have to wait to next year for something to happen.

[kestrel91316]

5. I betcha you'll be safe for at least the next month. Beyond that, it's

anybody's guess.

I am really thinking the time scales of their projections are going to continue accelerating downward.

[phantom power]

4. I thought it was established that this was due to lubrication by water.

[gulfcoastliberal]

6. I thought that too.

Huge freshwater rivers under the glaciers. Ice shelfs melt and then the glaciers can pour into the oceans.

[Delphinus]

7. Do we ever get firsthand accounts from the people

living in Greenland?

[hatrack]

8. They're out there - Gretel Ehrlich has a really interesting book on the Greenland Inuit

It's very measured and beautiful - This Cold Heaven is the title, I think.