Thursday, July 26, 2012

Whiteland

After being named Greenland for so long, but being snow white, maybe it's time for a change of name to Whiteland. In keeping with the obvious incongruity. It's going green whether the rest of us are or aren't.

And with major ramifications for rising sea levels.


NASA: Strange and sudden massive melt in Greenland
Nearly all of Greenland's massive ice sheet suddenly started melting a bit this month, a freak event that surprised scientists. What was unusual was that the melting happened in a flash and over a widespread area.

The ice melt area went from 40 percent of the ice sheet to 97 percent in four days, according to NASA. Until now, the most extensive melt seen by satellites in the past three decades was about 55 percent.

Even Greenland's coldest and highest place, Summit station, showed melting. Ice core records show that last happened in 1889 and occurs about once every 150 years.

Wagner and other scientists said because this Greenland-wide melting has happened before they can't yet determine if this is a natural rare event or one triggered by man-made global warming.

Whilst on an ice shelf in the white land far south, an important other dot was being connected:

Antarctic: Grand Canyon-sized rift 'speeding ice melt'
Antarctica is home to a geological rift system where new crust is being formed, meaning the eastern and western halves of the continent are slowly separating.

The team writes in Nature journal that the canyon is bringing more warm sea water to the ice sheet, hastening melt.

The Ferrigno rift lies close to the Pine Island Glacier where Nasa scientists found a giant crack last year; but the newly discovered feature is not thought to be influencing the "Pig", as it is known.

The rift lies beneath the Ferrigno Ice Stream on a stretch of coast so remote that it has only been visited once previously.

The British Antarctic Survey (BAS) project revisited the area two years ago in the person of Aberdeen University glaciologist Robert Bingham. The team towed ice-penetrating radar kit behind a snowmobile, traversing a total of about 2,500km (1,500 miles).

"What we found is that lying beneath the ice there is a large valley, parts of which are approximately a mile deeper than the surrounding landscape," said Dr Bingham. "If you stripped away all of the ice here today, you'd see a feature every bit as dramatic as the huge rift valleys you see in Africa and in size as significant as the [US] Grand Canyon.

"This is at odds with the flat ice surface that we were driving across - without these measurements we would never have known it was there."

The scientists suggest that during Ice Ages, when sea levels were much lower than at present, the rift would have channelled a major ice stream through the trough.

Now, they suggest, the roles are reversed, with the walls of the Belgica trough channelling relatively warm sea water back to the ice edge.

Ice loss from West Antarctica is believed to contribute about 10% to global sea level rise.
But how the West Antarctic and Greenland ice sheets respond to warmer temperatures is the biggest unknown by far in trying to predict how fast the waters will rise over the coming century and beyond.
A total melt of either sheet would raise sea levels globally by several metres.

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