Ice shelves melting at higher rate

Satellite images released this week showed signs of accelerated ice melting on the huge ice shelves surrounding the southern polar continent of Antarctica.

Warmer summer temperatures are thought to be causing their icy surface to melt. The weight of this water then carves deep cracks in the shelves. Computer modeling has shown a water-filled crack five to 15 metres deep can break up an ice field two times deeper than the length of a football field.

Through this break-up process, discussed in the latest issue of the Journal of Glaciology, a small amount of climate warming can eventually destroy an ice shelf and release giant rivers of glacial ice.

Antarctica’s Ross Ice Shelf is the largest piece of floating ice in the world — 600 to 3000 metres thick and as large as France. Studies have concluded it could begin breaking up within 50 years if global temperatures continue to rise, and if it collapses, sea levels could rise as much as three metres. Each vertical centimetre of rise would flood much more horizontal land, causing havoc in low-lying coastal regions.