Image courtesy of Greenpeace

News and other Busyness

Ice Shelves On The Move

Polar crack may be evidence of global warmingy

Squall 15, Summer 1997, pg. 15.

A massive 30-metre wide crack appeared in a polar ice shelf in Antartica in February - two years after the sudden collapse of an adjacent ice shelf covering 4,200 square kilometres.

The disintegration of the ice shelves - called Larsen A and Larsen B - was monitored by Greenpeace during "Polar Melt Down", a monthlong expedition to Antartica to document the effects of climate change.

Greenpeace say the crack in Larsen B, estimated at seven kilometres long, could presage another dramatic collapse. In Janurary 1995 4,200 square kilometres of its neighbour, Larsen A, dramatically fell into the sea.

The rapid deterioration of the ice shelves is, says Greenpeace, evidence of the effects of global warming which were first predicted to hit ice shelves as long ago as 1968.

Temperatures in the area have risen by 2.5 degrees celcius since 1945 - faster than anywhere else in the world.

Ice shelves are the floating sheets of ice which surround the continent of antartica, fringing half its coastline.

The Larsen shelf is near the northerly tip of antartica, looking towards the tip of South America.

Larsen A is to the North and Larsen B to the south.

While ice shelves naturally retreat and collapse during the summer, the deterioration of the Larsen shelves has been dramatic.

British antartic survey glaciologists have, according to Greenpeace, concluded that ice shelves are "sensitive indicators of climate change".

And scientists predict that ice shelves further south will begin to retreat further than ever before in the near future.

"It has taken centuries to millenia for these ice shelves to form and in a few short decades they are crumbling to nothing," said Erwin Jackson, a Greenpeace climate-change specialist who took part in the 'Polar Melt Down' tour. "From these sudden collapses, which are induced by local warming, it is clear that the vast bastions of floating ice around the edges of anartica are very fragile if human activities lead to more warming of the climate."

During their survey the Greenpeace ship, the MV Artic Sunrise, navigated a passage around James Ross Island - formerly impossible due to 200 metre-thick ice shelf which joined the island to the continent until 1995.

AJ