Collapse of Ice Bridge puts Antarctic ice shelf in peril
7 April 2009 - An ice bridge linking the Wilkins ice shelf to two islands in Antarctica has collapsed, triggering warnings that climate change is having a clear impact on the region.
A satellite picture from the European Space Agency (ESA) shows that a 40 km long strip of ice holding the Wilkins in place had splintered at its narrowest point, about 500 meters wide.
The Wilkins shelf, which is the size of Jamaica, has been retreating since the 1990s. It is one of many Antarctic ice shelves that have begun to break up over the past few decades and it is part of the Antarctic Peninsula, which has seen some of the most dramatic temperature increases in the area - up to 3 degrees, according to Elaine Baker of UNEP GRID-Arendal's Shelf Programme.
Christian Lambrechts, a Policy and Programme Officer with UNEP's Division of Early Warning and Assessment (DEWA), warned that the development was significant: "Although the Wilkins Ice Bridge collapse will have no direct consequence on sea level rise, it might have an indirect impact, as the decay of the ice shelf will reduce the stability of the glaciers that are feeding it," he said.
"The collapse of the Ice Bridge will expose a new expanse of sea surfaces that absorb an increased amount of solar radiation, contributing to continued and accelerated warming," he added.
According to research conducted in March 2009 by the World Meteorological Organization (WMO) for the International Polar Year (IPY), warming of the Antarctic is much more widespread than previously known. The research found that a freshening of the bottom water near Antarctica is consistent with increased ice melt from that continent that could affect ocean circulation.
Indeed, the loss of the Wilkins ice bridge, jutting about 20 meters out of the water and which was almost 100 km wide in 1950, may now allow ocean currents to wash away far more of the shelf.
A 2008 report released by UNEP and the World Glacial Monitoring Service (WGMS) showed that the average rate of glacial melting and thinning more than doubled between the years 2004-2005 and 2005-2006. The estimates, based on measuring the thickness of glacier ice, indicated an average loss of around 1.5 metres in 2006, up from just over half a metre in 2005.