Progressive thinning of the Larsen Ice Shelf

During the 20th century, the Antarctic Peninsula (AP) has experienced a considerable warming of climate, and several ice shelves have recently disintegrated. We used 9 years of European Remote Sensing (ERS) satellite radar altimeter measurements to determine the elevation change of the Larsen Ice Shelf (LIS), the most northerly ice shelf at the AP. We removed the periodic signal of ocean tide using a model derived from the same ERS dataset. Since 1992, the surface of the LIS has lowered by up to 0.27 +/- 0.17 m each year. This elevation change corresponds to 21 +/- 13 m of ice thinning, or 6 % of the ice shelf thickness. The thinning preceded the 2002 collapse of the Larsen B and has progressively weakened the remaining Larsen C, so that within 40 years it too may undergo a similar collapse.