Study: Antarctic Ice Sheets May Melt Even Faster than Previously Predicted

Antarctic ice has the potential to melt faster than predicted, and could contribute to sea level rise of up to six feet by 2100, according to a new report published Wednesday.

The research, published (pdf) in the journal Nature, finds that in a worst-case scenario of unabated carbon emissions, melting ice sheets in Antarctica could raise sea levels by 39 inches by 2100--double what United Nations climate scientists warned just three years ago, according to the study by University of Massachusetts Amherst professor Rob DeConto and Pennsylvania State University professor David Pollard.

With melting ice in other regions, the seas could rise by up to six feet, as the New York Times explained.

Even in a best-case scenario in which nations cap rising greenhouse gases as agreed to in the Paris climate deal last December, sea levels could still rise by three feet in that same time span.

And in the worst-case scenario, by the year 2500, melting Antarctic ice alone could raise sea levels by 42 feet.

"You're remapping the way the planet looks from space with those numbers, not just subtle changes about which neighborhoods are going to be susceptible to storm surge," DeConto told the Associated Press on Wednesday.

Still, in places on the U.S. East Coast, such as Boston, sea levels could rise by 25 percent more than the global average because of geological conditions, he said, adding, "North America has a lot to fear from ice loss in West Antarctica, which is where it all begins."

The paper used updated computerized models of Antarctica to assess factors recently recognized as contributing to glacier instability, such as the thinning or retreating of ice sheets. The Washington Post explains:

The scientists behind Wednesday's study used sophisticated computer models to decipher a longstanding riddle about Antarctica: how did it surrender so much ice during previous warm periods? They found that similar conditions in the future could lead to monumental and irreversible increases in sea levels. If high levels of greenhouse gas emissions continue, they concluded, oceans could rise by close to two meters in total (more than six feet) by the end of the century. The melting of ice on Antarctica alone could cause seas to rise more than 15 meters (49 feet) by 2500.

"Today we're measuring global sea level rise in millimeters per year," DeConto told New Scientist. "We're talking about the potential for centimeters per year just from [ice loss in] Antarctica."

The scientists also found that a committed effort to capping carbon emissions would present a fairly good chance of preventing catastrophic ice loss. That finding comes after other recent research which suggests that Antarctic collapse may be approaching an "unstoppable" tipping point.

The new report states that without atmospheric warming, the magnitude of ocean warming is "insufficient to cause the major retreat of the...East Antarctic basins."

The paper comes just a week after former NASA scientist Dr. James Hansen released a bombshell report which finds that the world may undergo massive sea level rise within decades, rather than centuries, as previously thought--a prediction which DeConto's study affirms, at least in part.

"We're in danger of handing young people a situation that's out of their control," Hansen said. The dangers they face include "superstorms stronger than any seen in modern times," the devastation of "all coastal cities," and ultimately, "how soon we will pass points of no return."