3D Antarctic Ice Map 'Clue' To Climate Change

Scientists exploring the frozen world beneath Antarctica have produced a three-dimensional map to help them better understand the impact of climate change.

The map was drawn up using data from a robotic submarine, which was driven through mountains and valleys to measure the thickness of the sea ice.

By combining the data with measurements taken from above the ground, scientists now have a far more accurate idea of how quickly the ice is melting.

Jan Lieser, an Antarctic marine glaciologist, said: "The ice thickness is regarded by climate scientists as the holy grail of determining changes in the system.

"If we can determine the change in the thickness of the sea ice, we can estimate the rate of change that is due to global warming."

Although scientists have had ice thickness data for the Arctic region since the 1950s, there has been no similar data for the ice around Antarctica.

Tests in 2007 produced only two dimensional maps, which are less accurate.

The Sea Ice Physics and Ecosystem Experiment (Sipex) project uses a robot equipped with sonar technology to measure the underside of the ice from 20 metres down.

The results are important because changes in sea ice thickness affect the formation of cold, salty water that drives global ocean currents and is crucial for sea life.

Ms Lieser said: "We can actually get a full 3D image of what we are measuring. It's never been done before and that's really exciting."

The Sipex expedition is made up of 45 scientists from eight countries, including Australia, Belgium, Canada, France, Germany, Japan, New Zealand and the United States.

They are using the 100 metre-long Australian icebreaker Aurora Australis as their research base.