March 18, 2009

West Antarctic ice sheet changes rapidly

U.S. climatologists say they've determined the West Antarctic ice sheet changes rapidly over the eons, most influenced by ocean temperatures.

Researchers at Pennsylvania State University and the University of Massachusetts said their findings were based on modeling 5 million years of changes in the ice sheet.

We found that the West Antarctic ice sheet varied a lot, collapsed and regrew multiple times over that period, said Penn State senior scientist David Pollard. The ice sheets in our model changed in ways that agree well with the data collected by the ANDRILL project.

Pollard and University of Massachusetts Professor Robert DeConto report their findings in the journal Nature. The results of the first ANDRILL drill core near McMurdo Station, Antarctica, are reported in a companion paper in the same issue.

The drilling project is a multinational collaboration to drill back in time into sediment to recover a history of paleoenvironmental changes.

Pollard said the researchers, as expected, determined the East Antarctic ice sheet is stable and does not slide into the sea and melt because most of its bedrock is above sea level, unlike the west Antarctic ice sheet.