Fast Glacier

April 30, 2017
By Damond Benningfield

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Retreating calving front of the Jacobshavn glacier in Greenland from 1851 - 2006. Credit: NASA

A glacier in Greenland has been moving at anything but glacial speeds in recent years. In the summer of 2012, it hit a top rate of 150 feet per day -- about 10 miles per year. As a result, it’s dumping more ice into the north Atlantic Ocean, and contributing to the rise in global sea level.

Jakobshavn Glacier flows from the center of Greenland toward its southwestern coast. As the glacier reaches the water, big chunks of ice break off. These icebergs travel through a long fjord into Davis Strait, which carries them to the Atlantic. The glacier is one of the main sources of north Atlantic icebergs. In fact, one of its bergs might have sunk the Titanic. And, the number and size of the icebergs are increasing.

From the mid-1800s to the early 2000s, the glacier’s leading edge retreated by about 12 miles. In other words, the glacier got that much smaller, as more of its ice broke off and floated out to sea. Since then, it’s retreated miles farther. And it could retreat another 30 miles by the end of the century. That’s a result of our planet’s warming climate, which has made the glacier thinner. With less weight, the remaining ice slides over the ground more easily, so it picks up speed.

As the glacier’s ice enters the ocean, it adds to global sea level. From 2000 to 2011, it contributed about a millimeter. And in the decades ahead, it could add more to the rising sea level than any other feature in the northern hemisphere -- one more way in which this glacier is anything but glacial.