Wednesday, September 16, 2009

Glaciers kick it up another gear, then get winded

Fresh research on glaciers that appeared to be moving especially fast in southeastern Greenland may raise as many questions as it answers.

In any event, it seems the frosty buggers have slowed a bit.

From the AP:

 Helheim Glacier nearly doubled its speed in just a few years, flowing through a rift in the barren coastal mountains at a stunning 100 feet (30 meters) per day.
   Alarm bells rang as the pattern was repeated by glaciers across Greenland: Was the island's vast ice sheet, a frozen water reservoir that could raise the sea level 20 feet if disgorged, in danger of collapse?
   Half a decade later, there's a little bit of good news and a lot of uncertainty.
   "It does seem that the very rapid speeds were only sustained for a short period of time although none of these glaciers have returned to the 'normal' flow speeds yet," says Gordon Hamilton, a glaciologist from the University of Maine, who's clocked Helheim's rapid advance using GPS receivers on site since 2005.
   Understanding why Greenland's glaciers accelerated so abruptly in the first half of the decade and whether they are now slowing down is crucial to the larger question of how fast sea levels will rise as the planet warms.

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