19 March, 2002 Press releases

PRESS RELEASE 19 March 2002 PR Number 5/2002

Satellite images have revealed the collapse of Larsen B ice shelf on the Antarctic Peninsula fulfilling predictions made by British Antarctic Survey (BAS) scientists. The collapse of the 3250 km? ice shelf is the latest drama in a region of Antarctica that has experienced unprecedented warming over the last 50 years.

Earlier this month Ted Scambos of the University of Colorado alerted BAS glaciologists David Vaughan and Chris Doake to images from the NASA MODIS satellite. Meanwhile, in Antarctica Argentinian glaciologist Pedro Skvarca, realised something was happening to the ice shelf and mobilised an aircraft to obtain aerial images confirming the satellite data. While the collapse was still occurring the BAS research ship RRS James Clark Ross navigated her way through the armada of icebergs to obtain photographs and samples.

Over the last month the 200-m thick ice shelf collapsed into small icebergs and fragments. Pooling these new observations scientists will determine when such an event last happened and which ice shelves are threatened in future.

BAS glaciologist Dr David Vaughan said,
“In 1998, BAS predicted the demise of more ice shelves around the Antarctic Peninsula. Since then warming on the peninsula has continued and we watched as piece-by-piece Larsen B has retreated. We knew what was left would collapse eventually, but the speed of it is staggering. Hard to believe that 500 billion tonnes of ice sheet has disintegrated in less than a month.”

(Satellite Image courtesy of Ted Scambos, National Snow and Ice Data Center, University of Colorado) Progression of the collapse of Larsen B from 1995 to the present. Back ground image acquired March 5, 2002 by the MODIS sensor on NASA’s Terra Satellite. (Image is approximately 300 x 300 km).

Click on above images for a larger version.

Issued by the British Antarctic Survey .

For more information please contact:

Linda Capper: British Antarctic Survey Press Office – Work: 01223 221448, Mobile: 07714 233744

Athena Dinar: British Antarctic Survey Press Office – Work: 01223 221414, Mobile: 07740 822229

Dr David Vaughan: 01223 221643

NOTES TO EDITORS

Operational Note: Dr David Vaughan will be available for interviews immediately after the opening of ‘Climate Change: the burning issue’ – an antenna exhibition at the Science Museum, London – 09.00-11.00 Tuesday 19 March 2002

During the last 50 years the Antarctic Peninsula has warmed by 2.5?C, much faster than mean global warming. One response to climate change has been the retreat of five ice shelves, floating extensions of the grounded ice sheet. In 1998, Scientists of the British Antarctic Survey used numerical models to predict the future of one ice shelf, Larsen B and said that if it “were to retreat by a further few kilometres, it too is likely to enter an irreversible retreat phase” . Dr Chris Doake, Nature (Vol. 391, pages 778-780)

The rate of warming on the Antarctic Peninsula is rapid and unmatched elsewhere in Antarctica (Vaughan et al., 2001 Science , Vol. 293, pages 1777-1779).

As it is already floating the disintegration of Larsen will have no impact on sea level. Sea level will rise only if the ice held back by the ice shelf flows more quickly onto the sea. The collapsed ice shelf at 3250 km? is larger than Luxembourg (2586 km?) or just smaller than Cambridgeshire 3409 km?.

British Antarctic Survey is responsible for most of the UK’s research in Antarctica. It is a component of the Natural Environment Research Council. More information about the work of the Survey can be found on this website. Images and pictures of the ice shelf collapse are available from the BAS press office.