Ice sheets in West Antarctica are collapsing and it is not reversible, causing scientists to ring the rising sea level alarm.

According to the Associated Press, researchers have published two new studies that agree the ice melt is moving much quicker than originally thought. Still, the study authors were talking in terms of hundreds of years in which the sea level is expected to rise four to 12 inches.

"There's been a lot of speculation about the stability of marine ice sheets, and many scientists suspected that this kind of behavior is under way," Ian Joughin, a glaciologist at the University of Washington's Applied Physics Laboratory, said in a press release. "This study provides a more quantitative idea of the rates at which the collapse could take place."

The UW team's study is set to be published May 16 in the journal Science.

"This sector will be a major contributor to sea level rise in the decades and centuries to come," Eric Rignot, of the University of California, Irvine and NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., said in a statement. "A conservative estimate is it could take several centuries for all of the ice to flow into the sea."

Rignot is the lead author of a study accepted for publication in the journal Geophysical Research Letters.

"The grounding line is buried under a thousand or more meters of ice, so it is incredibly challenging for a human observer on the ice sheet surface to figure out exactly where the transition is," Rignot said. "This analysis is best done using satellite techniques."

Ted Scambos, lead scientist at the National Snow and Ice Data Center, was not involved in either study, but was among outsiders who praised both pieces of work.

"It's bad news. It's a game changer," he told the AP. "We thought we had a while to wait and see. We've started down a process that we always said was the biggest worry and biggest risk from West Antarctica."