Oregon State University scientists say the rapid breakdown of some parts of the Greenland and Antarctica ice sheets is disturbing.

Researchers from Oregon State and four other institutions say the dynamic mechanisms of glacial change apparently under way could significantly speed up major ice sheet melting, and have not been considered in current projections for sea level rise.

The researchers say current sea level rise projections based on global warming should be considered a minimum to expect.

"Most of the sea level rise we're expecting during the next 200 years is due to thermal expansion of water, not the overall loss of ice from Greenland and Antarctica," said Peter Clark, a professor of geosciences.

"But recent ... computer modeling suggests there may be much more going on. We may be more vulnerable to sea level rise than we thought and it may be more rapid than we have anticipated," Clark said. "This is an issue we should take very seriously."

Other collaborators on the study were from Pennsylvania State University, the University of Washington and institutes or universities in Germany and Belgium.

The research is detailed in the journal Science,

Copyright 2005 by United Press International