Greenland Glacier Sheds Another Big Chunk

JUN 11, 2014 04:22 PM ET // BY PATRICK J. KIGER


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Those of us who aren’t in the Arctic often think of ice as rigid, but glaciers actually move and break off pieces of themselves — now, even more so, thanks to climate change. One of the world’s most dynamic glaciers is Greenland’s Jakobshavn Isbrae, which in recent years has been speeding up to a record pace and adding more and more ice to the ocean, contributing about a millimeter to global sea-level rise by itself from 2000 to 2011.

These images taken in May (above) and June by NASA’s Landsat 8 satellite show Jakobshavn in the process of cracking and “calving” a huge piece of ice, somewhere between 3.1 and 6.2 square miles in size, according to the Arctic Sea Ice Blog.

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In the June image, below, a big area of the glacier’s southern branch and a smaller section of its northern branch have been altered, and ice has crumbled from the glacier’s front into the mélange, an accumulation of pieces that are floating downstream from it.




Jakobshavn has moved 25 miles since 1850. The glacier’s tongue-shaped edge sits ina deep valley about 4,260 feet above sea level, which doesn’t provide much resistance to slow the glacier’s slide into the ocean.

Since 2000, Greenland has lost some 739 gigatons of ice, and approximately 30 percent of that loss came from Jakobshavn and four other glaciers, according to NASA.

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The glacier has another disturbing historical distinction. According to Richard Brown’s bookVoyage of the Iceberg, an iceberg calved by Jakobsavn in 1910 — one of 10,000 that broke away from the glacier that summer — eventually drifted into the path of the Titanic on April 14, 1912. That iceberg may be depicted in this photo taken by the captain of another ship, the Etonian, two days earlier.

http://news.discovery.com/earth/ocea...unk-140611.htm