Thursday, July 11, 2013

Water, water, everywhere

By Carl

And not a drop to drink. But you may drown:
Researchers from the Vrije Universiteit Brussel, funded by ice2sea, a European Union project, tackled the question of how both processes will evolve and interact in the future.

This was done with a computer model, which projects the future ice sheet evolution with high accuracy using the latest available techniques and input data.

They devised a method to generalize projections made in earlier research which concerned just four of Greenland's outlet glaciers. By doing so they could apply the earlier findings to all calving glaciers around the Greenland ice sheet.

Their results indicate a total sea-level contribution from the Greenland ice sheet for an average warming scenario after 100 and 200 years of 7 and 21 cm, respectively.

Well, this all seems…horrible. I mean, 21 cm doesn’t sound like much, not even a foot, but…
So why does it matter what happens to the ice sheets? Well, estimates from the National Snow and Ice Data centre (NSIDC) suggest that total melting of the Greenland and Antarctic ice sheets would, between them, release enough fresh water to increase global sea level by approximately 66m, of which Greenland’s contribution would be around 6m (other estimates vary).

Since it seems that the melting of Greenland’s ice sheet is proceeding at a pace that outstrips earlier projections, it’s safe to assume scientists here are being more hopeful than helpful. Now, look at those numbers again in that second quote. 6m is roughly 20 feet, so 66m is…about the height of a 20 story building.

I think there might be a problem, and it might be worse than even that:
A massive iceberg, larger than the city of Chicago, broke off of Antarctica's Pine Island Glacier on Monday (July 8), and is now floating freely in the Amundsen Sea, according to a team of German scientists.

The newborn iceberg measures about 278 square miles (720 square kilometers), and was seen by TerraSAR-X, an earth-observing satellite operated by the German Space Agency (DLR). Scientists with NASA's Operation IceBridgefirst discovered a giant crack in the Pine Island Glacier in October 2011, as they were flying over and surveying the sprawling ice sheet.

Keep in mind, it’s the coldest part of the year down there. This calved because of warmer sea water, driven by winds from the north, slid into the cracks and split the berg off. It would have happened eventually, but more likely when it was Antarctic summer.

(Cross-posted at Simply Left Behind.)

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