Warm Ocean Causing Most Antarctic Ice Shelf Loss

This photo shows the ice front of the ice shelf in front of Pine Island Glacier, a major glacier system of West Antarctica. The image was taken during the NASA/Centro de Estudios Cientificos, Chile (CECS) Antarctic campaign of Fall 2002. Image credit: NASA/JPL-Caltech/UC Irvine

Rates of basal melt of Antarctic ice shelves (melting of the shelves from underneath) overlaid on a 2009 mosaic of Antarctica created from data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA's Terra and Aqua spacecraft. Red shades denote melt rates of less than 5 meters (16.4 feet) per year (freezing conditions), while blue shades represent melt rates of greater than 5 meters (16.4 feet) per year (melting conditions). The perimeters of the ice shelves in 2007-2008, excluding ice rises and ice islands, are shown by thin black lines. Each circular graph is proportional in area to the total ice mass loss measured from each ice shelf, in gigatons per year, with the proportion of ice lost due to the calving of icebergs denoted by hatched lines and the proportion due to basal melting denoted in black. Image credit: NASA/JPL-Caltech/UC Irvine/Columbia University

Calving front of an ice shelf in West Antarctica. The traditional view on ice shelves, the floating extensions of seaward glaciers, has been that they mostly lose ice by shedding icebergs. Image credit: NASA/GSFC/Jefferson Beck  

Ocean waters melting the undersides of Antarctic ice shelves are responsible for most of the continent's ice shelf mass loss, a new study by NASA and university researchers has found.

This study - the first comprehensive survey of all Antarctic ice shelves - found basal melt accounted for 55 percent of all Antarctic ice shelf mass loss from 2003 to 2008, an amount much higher than previously thought.