Retreat of northern margins of George VI and Wilkins Ice Shelves, Antarctic Peninsula

The George VI and Wilkins Ice Shelves are considered at risk of disintegration due to a regional atmospheric warming trend on the Antarctic Peninsula. Retreat of the northern margin of the George VI Ice Shelf has been observed previously, but the Wilkins Ice Shelf was thought to be stable. We investigated the positions of the northern fronts of these shelves from the literature and looked for changes on 1974 Landsat and 1992 and 1995 European remote-sensing satellite (ERS) synthetic aperture radar images. Our investigation shows that the northern George VI Ice Shelf lost a total of 906 km 2 between 1974 and 1992, and an additional 87 km 2 by 1995. The northern margin of the Wilkins Ice Shelf lost 796 km 2 between 1990 and 1992, and another 564 km 2 between 1992 and 1995. Armadas of tabular icebergs were visible in front of this shelf in the ERS images. These two ice shelves mark the southernmost documented conspicuous retreat of ice-shell margins.