Antarctic ice shelves at risk of collapse

A number of floating ice shelves in Antarctica are at risk of disappearing entirely in the next 200 years, as global warming reduces their snow cover, a new study has found.

Their collapse would enhance the discharge of ice into the oceans and increase the rate at which sea level rises.

Scientists have been observing ice-shelf retreat around the Antarctic Peninsula since the early 1990s, but a new model provides for the first time a strong basis for the prediction of future changes - a major step forward in understanding future sea-level changes.

A rapid reduction of greenhouse gas emissions could save a number of these ice shelves, researchers at Utrecht University and the British Antarctic Survey say in a paper published yesterday in the Journal of Glaciology.

In 1995 and 2002, two floating ice shelves in the north of the Antarctic Peninsula - Larsen A and B - suddenly collapsed.

"This was a spectacular event, especially when you imagine the size of these ice shelves, which are several hundreds of metres thick, and have been in place for over 10,000 years," said Dr Peter Kuipers Munneke, the paper's lead author.

The team of researchers suspected that the disappearance of the snow layer on top of the ice shelves could be an important precursor for shelf collapse.

Their calculations show that many more ice shelves are in danger of collapse.

"If we continue to burn fossil fuels at the current rate, almost all ice shelves in the Antarctic Peninsula will be under threat of collapse in the next 200 years," Dr Kuipers Munneke said.

The study received financial support from the European Union's four-year ice2sea project.

- Jamie Morton of the New Zealand Herald

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