About Antarctic Ice Shelves

Forty-four percent of Antarctica's coastline is made up of ice shelves — thick slabs of ice attached to the shore, and extending out over the ocean. Ice shelves range in thickness from about 200-2,500 meters (656-8,202 feet), and can persist for thousands of years. At their seaward edge, ice shelves periodically calve icebergs, some the size of a small U.S. state. Because they are exposed to both warming air above and warming ocean below, ice shelves respond more quickly than ice sheets or glaciers to rising temperatures.

According to several studies spanning several decades, ice shelves are thinning at a faster rate because of warmer ocean water. Geothermal heat (heat from underground) leftover from 34-plus million years ago does not contribute to this thinning, its effect being less than one five-hundredth of a 75-watt lightbulb.