Ancient ice provides clues to future climate change

Basler aircraft used for the ICECAP project on the ground at Casey skiway
Basler aircraft used for the ICECAP project at Casey skiway (Photo: Paul Helleman)
The Totten Glacier in East Antarctica reaches the Southern Ocean in a jumble of broken ice on the southeast side of Law Dome.

23 November 2009

Australian, British, American and French scientists have teamed up to learn more about the East Antarctic ice sheet to better predict sea level rise and search for the continent's oldest ice, predicted to be up to 1.3 million years old.

The ICECAP (Investigating the Cryospheric Evolution of the Central Antarctic Plate) project is using a radar equipped plane to fly over East Antarctica this summer to map the thickness of the ice sheet and explore the underlying bedrock.

Australian Antarctic Division glaciologist, Dr Tas van Ommen, said the team is hoping to identify where the oldest ice may be found and with it, an ancient climate record.

"We think the oldest ice will be somewhere in the Australian Antarctic Territory because that's where the ice sheet is the thickest and where snowfall rate is smallest in Antarctica," Dr van Ommen said.

"It's reasonable to think we might find ice that's well over a million years old and extracting it by deep ice drilling would help us understand why the natural pacing of the ice ages experienced a major shift at that time," Dr van Ommen said.

He said understanding the role of carbon dioxide in past climate changes will provide important insights into the impact of on our climate of increasingly elevated levels of carbon dioxide.

The ICECAP flights will also provide crucial information to help better predict loss of continental ice and sea level rise.

"At the moment models used to predict sea level rise do not fully account for the complex changes of ice flow and melt that are occurring" Dr van Ommen said.

"For example at the Totten Glacier, near Casey station, much of the bedrock is below sea level and this may be resulting in increasing melt from contact with a warming ocean," Dr van Ommen said.

"This would explain satellite observations which show the surface of the glacier lowering," he added.

The research will identify areas of the continent where the bedrock is lower than sea level and help to model what impact that might have on hastening ice loss and increasing sea level rise.

The scientists will undertake about 15 flights over Totten Glacier and the East Antarctic coastline in December.

ICECAP is a joint project between Australian Antarctic Division, University of Texas, University of Edinburgh and the French Antarctic Program, with support from the US National Science Foundation, NASA and UK National Environment Research Council.