American Association for the Advancement of Science
Where the ice shelf ends
New findings should help researchers predict the rate at which ice shelves, the thick, floating lips of ice sheets or glaciers that extend out past the coastline, break apart into icebergs.
This often-spectacular event, known as calving, is an important step in the chain of events by which global warming leads to sea level rise. Currently, computer models that simulate how ice sheets may behave in a warmer world generally gloss over the calving process, because researchers haven't understood what controls it.
In a Brevium, Richard Alley of Pennsylvania State University and his colleagues assembled new and published data from a range of ice shelves and determined that the main thing controlling an ice shelf's calving rate is the rate at which the ice shelf is spreading away from the continent.
This spreading leads to the cracking that eventually causes the edges of the ice shelves to go crashing into the ocean.
These findings appear in the 28 November issue of the journal Science.