Saturday, June 14, 2008

Wilkins Ice Shelf Just Got Smaller

Starting on May 30, a large chunk broke off of the Wilkins Ice Shelf on the Antarctic Peninsula even though it is winter in Antarctica.

Wilkins Ice Shelf, a broad plate of floating ice south of South America on the Antarctic Peninsula, is connected to two islands, Charcot and Latady. In February 2008, an area of about 400 km² broke off from the ice shelf, narrowing the connection down to a 6 km strip; this latest event in May has further reduced the strip to just 2.7 km.

This animation, comprised of images acquired by Envisat’s Advanced Synthetic Aperture Radar (ASAR) between 30 May and 9 June, highlights the rapidly dwindling strip of ice that is protecting thousands of kilometres of the ice shelf from further break-up.

According to Dr Matthias Braun from the Center for Remote Sensing of Land Surfaces, Bonn University, and Dr Angelika Humbert from the Institute of Geophysics, Münster University, who have been investigating the dynamics of Wilkins Ice Shelf for months, this break-up has not yet finished.

"The remaining plate has an arched fracture at its narrowest position, making it very likely that the connection will break completely in the coming days," Braun and Humbert said.
Wilkins is one of seven Antarctic ice shelves that have either collapsed or lost much of their volume in the past 20 years. The recent collapses are all linked to climate change. The Antarctic Peninsula's average yearly temperature has risen by 2.5°C over the past 50 years. Warming there is proceeding at a fast pace compared to the rest of the world, which has warmed 0.6°C over the past 100 years. With continued warming, the remaining ice shelves may well disappear.

You can find an animation of the most recent breakup at the link above and a more technical explanation of ice shelf breakup at RealClimate.