Vast Antarctic Ice Shelf on Verge of Collapse

[XemaSab]

A vast ice shelf hanging on by a thin strip looks to be the next chunk to break off from the Antarctic Peninsula, the latest sign of global warming's impact on Earth's southernmost continent.

Scientists are shocked by the rapid change of events.

Glaciologist Ted Scambos of the University of Colorado was monitoring satellite images of the Wilkins Ice Shelf and spotted a huge iceberg measuring 25 miles by 1.5 miles (41 kilometers by 2.5 kilometers - about 10 times the area of Manhattan) that appeared to have broken away from the shelf.

"Wilkins is the largest ice shelf on the Antarctic Peninsula yet to be threatened," he said. "I didn't expect to see things happen this quickly. The ice shelf is hanging by a thread - we'll know in the next few days and weeks what its fate will be."

http://news.yahoo.com/s/livescience/20080325/sc_livescience/vastantarcticiceshelfonvergeofcollapse

[n2doc]

1. pics and video here

http://www.antarctica.ac.uk/press/press_releases/press_release.php?id=376

British Antarctic Survey has captured dramatic satellite and video images of an Antarctic ice shelf that looks set to be the latest to break out from the Antarctic Peninsula. A large part of the Wilkins Ice Shelf on the Antarctic Peninsula is now supported only by a thin strip of ice hanging between two islands. It is another identifiable impact of climate change on the Antarctic environment.
Scientists monitoring satellite images of the Wilkins Ice Shelf spotted that a huge (41 by 2.5 km) km2 berg the size of the Isle of Man appears to have broken away in recent days – it is still on the move.
Glaciologist Ted Scambos from the University of Colorado alerted colleagues Professor David Vaughan and Andrew Fleming of the British Antarctic Survey (BAS) that the ice shelf looked at risk. After checking daily satellite pictures, BAS sent a Twin Otter aircraft on a reconnaissance mission to check out the extent of the breakout.
Professor Vaughan, who in 1993 predicted that the northern part of Wilkins Ice Shelf was likely to be lost within 30 years if climate warming on the Peninsula were to continue at the same rate, says,
"Wilkins is the largest ice shelf on the Antarctic Peninsula yet to be threatened. I didn't expect to see things happen this quickly. The ice shelf is hanging by a thread – we'll know in the next few days or weeks what its fate will be."

[gasperc]

3. Sadly, professor Vaughn was within 30 years

15 years too soon!!

[gasperc]

2. no one could have predicted, trapping the earth's heat

would melt the polar ice caps, except people with functioning brains, and teenagers, and pre-schoolers, and oh yeah, those sciency people, Al Gore to name at least one guy...

[zazen]

4. stupid person wants to know: is this the sea-level rising kind?

I can't keep it straight. What's the ice that'll "just" send lots of fresh water into the sea and create more heat-absorbing ocean-surface, and what's the ice that will do that and also cause sea-level to rise?

dumbass in North Carolina

[n2doc]

6. not a dumb question

This is the non sea level rising kind. Think of ice cubes in a glass of water. Since it is already floating in the sea when it melts it only adds fresh water. The problem with losing these is that all the ice sitting behind them, on land, begins to flow faster into the sea since it is no longer dammed up. And that kind of ice input does raise sea levels.

[zazen]

8. thanks! now I understand

[OKIsItJustMe]

11. If I may make a trivial observation...

Very few people put ice cubes into salt water (i.e. sea water.)

When ice cubes, floating in fresh water melt, they don't raise the water level. (They were displacing their mass of fresh water, and when they melt, they add just the volume they were displacing.) On the other hand, ice cubes floating in salt water (which is slightly denser than fresh water) will cause the water level to rise a little. (They were displacing their mass in salt water, but have added their volume of fresh water.)

However, the density difference (while significant) is quite small.

[hatrack]

5. Wow . . . it's almost as if things were happening . . .

. . . Faster Than Expected, or something like that.

[tom_paine]

9. We need to put it to rap music. F-f-f-fuh-fuh-fuh-fuh-faster, f-faster!

Th-th-th-th-th-th-th-th-th than expected!

Than Exp-p-p-p-p-p-ected!

[depakid]

12. With speed and violence....

[hatrack]

7. K&R

:toast: - Drink up, y'all. Not much else we can do at this point.

[hatrack]

10. Satellite imagery from NSIDC - collapse took eight days

Be sure to scroll over to the right to get the time sequence.

[XemaSab]

13. One of the things from these pictures:

The ice doesn't look very thick. I would think that if you had the disintigration of a thick ice shelf, the ice would not be in even "tiles" like that. I would guess that the bergs would start melting and rolling if they were thick and irregular.

Or is my conceptualization wrong here?