Geology News
Antarctic cycles could aid warming prediction October 18, 2001
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New research, extending our knowledge of climatic cycles into the early Neogene, could aid predictions in 21st century climate systems
Research by Professor Jaap van der Meer, of Queen Mary, University of London's Geography department, and colleagues, could lead to more accurate predictions on the future of climate change.
The Cape Roberts Project, initiated in 1997 and whose research is published today (18 October) in Nature, was a major international research scheme involving thirty-three scientists from all over the world . The scientists examined clues to Antarctica's history hidden in the sediments from the sea-bed at Cape Roberts, off the coast of Victoria Land (Antarctica), in an attempt to extend our knowledge of climatic cyclicity back many millions of years.
Between 15 and 34Ma ago when the temperature on earth was 3-4ºC hotter than today and atmospheric CO2 concentrations were twice as high as they are now, the Antarctic ice sheet varied considerably in size. The Cape Roberts Project researchers have been able to show that between 24.1 and 23.7 Ma ago (the base of the Neogene), the massive East Antarctic ice sheet expanded and contracted regularly relative to the variances in the Earth's orbit around the Sun, producing changes in sea level of up to 60m.
The new research focused on sediment data from rock cores from the seabed of Western Ross Sea, drilled between 1997 and 1999. Using this material, researchers were able to calibrate the inferred changes in ice volume with direct evidence for oscillations of the Antarctic ice sheet.
Professor van der Meer said: "We have always assumed that the Antarctic ice sheet oscillated, now we know that it did and at what frequency. This provides a much better tool for predicting its future behaviour".