Petermann Glacier Set to Lose Chunk of Ice the Size of Manhattan
15.07.2009 - Ice & Snow, Other, Arctic
The Petermann Glacier in Greenland, the largest glacier in the Arctic, appears as if it will shortly lose a 100km2 chunk of ice, an area roughly the same size as Manhattan Island.
Normally glaciers lose ice all the time at their termini, where the ice flowing out of them usually forms an ice shelf over open water, off of which icebergs calve into the sea. The ice they lose is usually replenished by snowfall over the interior of the ice sheet.
However the amount of ice that will soon break off is alarming scientists, as it would weigh somewhere close to 5 billion tons, which is nearly half of the Petermann Glacier's annual flow. The glacier's flow rate has also increased significantly over the past few years, with a chunk of ice weighing 1 billion tons breaking off last year. Experts believe the acceleration is likely due to a number of factors including warmer ocean currents that are melting the ice from below and warmer air temperatures that are melting it from above.
Researchers, including Ohio State University's Dr. Jason Box, have been monitoring the Petermann Glacier and other glaciers in Greenland for many years. Last year when Dr. Box visited the Petermann Glacier he noticed a 16 kilometre-wide crack in the glacier's floating ice tongue, which passes through a fjord on its way out to sea. This year Dr. Box has returned with a large number of cameras and sensors, which have been set up on the ice shelf and surrounding cliffs, to record this major event. Regular updates are being posted on a blog dedicated to the expedition.
Once the huge section of ice breaks off the smaller ice tongue will provide less resistance for the glacier as it flows out to sea, allowing the galcier's flow to accelerate. This would lead to accelerated ice loss from the Greenland Ice Sheet, which contributes to sea level rise.
