Rising climate warning affecting stability of West Antarctic Ice Sheet

March 19th, 2009 - 1:42 pm ICT by ANI  

Washington, March 19 (ANI): New evidence has emerged which determines that even a slight rise in atmospheric concentrations of carbon dioxide, one of the gases that drives global warming, affects the stability of the West Antarctic Ice Sheet (WAIS).

The massive WAIS covers the continent on the Pacific side of the Transantarctic Mountains. Any substantial melting of the ice sheet would cause a rise in global sea levels.

The evidence was collected by a 56-member team of scientists, which conducted a research on a 1,280-meter (4,100-foot)-long sedimentary rock core taken from beneath the sea floor under Antarcticas Ross Ice Shelf during the first project of the ANDRILL (ANtarctic geological DRILLing) research program.

The sedimentary record from the ANDRILL project provides scientists with an important analogue that can be used to help predict how ice shelves and the massive WAIS will respond to future global warming over the next few centuries, said Ross Powell, a professor of geology at Northern Illinois University.

The sedimentary record indicates that under global warming conditions that were similar to those projected to occur over the next century, protective ice shelves could shrink or even disappear and the WAIS would become vulnerable to melting, he added.

If the current warm period persists, the ice sheet could diminish substantially or even disappear over time. This would result in a potentially significant rise in sea levels, he further added.

According to Tim Naish, director of Victoria University of Wellingtons Antarctic Research Centre, the new information gleaned from the core shows that changes in the tilt of Earths rotational axis has played a major role in ocean warming that has driven repeated cycles of growth and retreat of the WAIS for the period in Earths history between 3 million and 5 million years ago.

It also appears that when atmospheric carbon dioxide concentrations reached 400 parts per million around four million years ago, the associated global warming amplified the effect of the Earths axial tilt on the stability of the ice sheet, he said.

Carbon dioxide concentration in the atmosphere is again approaching 400 parts per million, Naish added.

According to Naish, Geological archives, such as the ANDRILL core, highlight the risk that a significant body of permanent Antarctic ice could be lost within the next century as Earths climate continues to warm.

Based on ANDRILL data combined with computer models of ice sheet behavior, collapse of the entire WAIS is likely to occur on the order of 1,000 years, but recent studies show that melting has already begun, he added. (ANI)

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