Which are the fastest moving glaciers on Earth? - Geography for You

Which are the fastest moving glaciers on Earth?

Greenland was recently found to have what is thought to be the world's fastest moving glacier. It's named the Jakobshavn Glacier, the same one that's believed to have spawned the iceberg that was the Titanic's undoing. Based on the latest assessments of its behavioral patterns, its summer flow speed is approximately 4 times the rate it did in the 1990s. Thus far it's -- or any glacier's -- highest speed was 46 meters per day, which was recorded in the summer of 2012. Some of the increase can be attributed to the warmer summer temperatures, but scientists point out that the average annual speed of the glacier's flow has increased over the years. Up until the 90s, Jakobshavn was considered to be pretty stable. Around that time its behavior changed and since then its yearly retreats have been speeding up. At the rate it is now going, it could contribute more than it has been to rising sea levels. Between 2000 and 2010, the glacier caused a 1-millimeter increase.That may not sound like much, but if all of Greenland's Ice Sheet were to melt it could cause catastrophic sea level rises.

Jakobshavn Isbrae is an ice stream, which means that it is very large, drains a large proportion of the ice sheet, and flows very quickly. Look at the table to see the velocities measured for some of the fastest glaciers in the world.

GlacierGlacier typeLocationSpeedDate measured
Jakobshavn IsbraeIce streamGreenland Ice Sheet12600 m per year2003
Pine Island GlacierIce streamWest Antarctica2075 m per year2007-2008
Fox Glacier (seracs in upper ice fall)Valley glacierNew Zealand182 m per year1991

What is an ice stream?

Ice streams are corridors of fast flow within an ice sheet (ca. 800 metres per year). They discharge most of the ice and sediment from these ice sheets, flowing orders of magnitude faster than their surrounding ice. Their behaviour and stability is therefore essentially important to overall ice sheet dynamics and mass balance[1]. The Antarctic Ice Sheet currently discharges 90% of ice and sediment through ice streams. Antarctic Ice Streams are fed by complex tributaries that extend up to 1000 km into the interior of the ice sheet[2]. These can be seen beautifully in the video below, released by NASA
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