Antarctic Glaciers Accelerating

A British Antarctic Survey (BAS) report issued on Wednesday states that sea level rise is being compounded by "hundreds of glaciers on the Antarctic Peninsula" that have begun to flow faster and farther. The research study was published in the Journal of Geophysical Research.

The Antarctic's temperature has steadily risen over the last half century. It is now 3 degrees centigrade higher than it is was 50 years ago. This may not sound significant, but the BAS quotes Dr. Hamish Pritchard, who is the study's lead author, as saying, "The Antarctic Peninsula has experienced some of the fastest warming on Earth."

This warming, which is considered rapid when viewed on a global climatic scale, has caused 87 percent of Antarctic glaciers to retreat (shrink) over the same period of time as the warming. Current studies by the BAS show that these glaciers are now speeding up and moving faster and farther.

It is known, according to the BAS, that global climate warming is "already causing" an increase of summer snow melt and ice shelf retreat in the Antarctic Peninsula. Current science indicates that the most likely probable cause for the accelerated and farther flow of Antarctic glaciers is also global climate warming.

Dr. Pritchard stresses the necessity for using satellite technology to monitor regional changes in "remote and inaccessible glaciers." Monitoring needs to occur on regional levels via satellite technology and not be restricted to observable local levels. As sea levels rise, it will be important to make accurate predictions that can form the basis of correct government policy. Pritchard also says satellite technology "now gives our best chance" to make informed, dependable predictions about global changes in the future.

In the current study, a team of BAS scientists headed by Dr. Pritchard used radar images from the European ERS-1 and -2 satellites to track the flow rate of 300 previously unstudied glaciers. A 12% increase in glacier speed was detected in the decade between 1993 and 2003.

The findings corroborate previous findings from coastal Greenland. Further, they provide a clearer picture of the ways global climate warming can affect glaciers in the Arctic and Antarctic. The United Nations Intergovernmental Panel on Climate Change (IPCC) acknowledges a lack of understanding of how large Antarctic ice sheets behave. The IPCC reports that because of this lack, they have been unable to provide an upper limit to the amount of sea-level rise expected in coming centuries, which will result directly from accelerated glacier activity in Antarctica.

Satellite supported studies will be critical to making reliable predictions of sea level rise. Proper policy decisions further depend on reliable climate science that broadens understanding and leads to accurate projections of global change.

The BAS report says that the European ERS-1 and -2 satellite radar images indicate the cause of the acceleration in Antarctica is the "melting of the lower glaciers." Lower glaciers flow directly into the sea. As these melt, they also thin. As they thin, the upper glaciers that they support experience a change to their foundational beds. This occurs because glaciers have natural buoyancy, the thinning below in the lower glaciers allows interior glaciers, which do not flow directly into the sea, to lift off their rock beds. These glaciers are thus allowed to begin a faster slide, an accelerated movement which is now being recorded and reported.

British Antarctic Survey is a national UK agency. For the past 60 years, BAS has been responsible for the majority of the UK's scientific work in the Antarctic, operating five research stations, two Royal Research Ships, and five aircraft all engaged in scientific study of Antarctica.

British Antarctic Survey, "Hundreds Of Antarctic Peninsula Glaciers Accelerating As Climate Warms." URL: http://www.antarctica.ac.uk/News_and_Information/Press_Releases/story.php?id=307