The World's Fastest Glacier Is Speeding Up

As scientists have watched it for decades, Greenland’s semi-famous Jakobshavn glacier has been speeding up. In a study released today in the journal The Cryosphere, a team of researchers revealed that the mean annual speed of the glacier was nearly three times as great as it was in the mid-1990s and in just over a decade, the glacier alone raised the global sea level by a millimeter.

Glaciers are known for moving at a geologic—which is to say slow—pace, so any discussion about “speed” can only be described relative to themselves. According to the researchers, at its peak during the summer of 2012 the glacier reached a world record speed of 46 meters a day—flowing faster than any glacier in Antarctica or Greenland on record.

As the National Snow & Ice Data Center explains, glaciers periodically retreat or advance, depending on the amount of snow accumulation or loss that occurs throughout the year. The Jakobshavn glacier had been relatively stable until the late 90s when the glacier’s ice tongue began to break up. Since then, its annual retreats during the summer have become progressively faster and deeper.

Since 2009, researchers have been using data collected by the German Space Agency’s TerraSAR-X to track the Jakobshavn glacier, as it gained speed—steadily from 2004 to 2011, and then an increase by 50 percent from 2011 to 2012, more than a kilometer further inland than in previous years.

"We are now seeing summer speeds more than 4 times what they were in the 1990s on a glacier which at that time was believed to be one of the fastest, if not the fastest, glacier in Greenland," Ian Joughin, the study’s lead author and a researcher at the Polar Science Center, University of Washington, said in a statement.

One of the many canaries in the climate coalmine, glaciers have been in retreat worldwide. Many, like the Jakobshavn, are retreating at unprecedented rates. Their retreat sometimes reveals interesting things— troops lost in battles nearly a century ago , a Neolithic man frozen 5,000 years ago, but mostly what’s revealed is the speed at which the global climate is changing.

If all of the ice on Greenland were to melt, the sea would rise by 65 meters. The single millimeter that the Jakobshavn glacier added to the world ocean between 2000 and 2011, while not a huge amount on its own, demonstrates that what once sounded abstract is increasingly becoming a demonstrable and chilling reality.