And it says with ice also melting in other parts of the world, seas could rise 5 or 6 feet by the end of this century, far more than predicted in a 2013 U.N. study.
"We're looking at the potential for a rate of sea level rise that we will be measuring in centimeters (rather than milliliters) per year -- literally an order of magnitude faster," said Robert DeConto of the University of Massachusetts Amherst, one of the study's authors.
"Can we build walls and levies and dikes fast enough to keep up with that? One concern would be that at that point you're sort of looking at managed retreat essentially, rather than geoengineering in a lot of places."
The study, by DeConto and David Pollard of Pennsylvania State University, says by 2500, Antarctica could contribute to a rise in sea levels of 15 meters, or nearly 50 feet.
"At the high end, the worst-case scenarios, with sort of business as usual greenhouse gas emissions ... we will literally be remapping coastlines," Deconto told CNN.
And by the middle of the next century, seas could be rising at a rate of more than 1 foot per decade if the emission of greenhouse gases continues unchanged, the study says.
"North America is kind of a bull's eye for impacts of sea level rise if it's the west Antarctic part of Antarctica that loses the ice first," DeConto said. "That's the place that we're worried about losing ice first."
DeConto predicts an industry boom in demolition and rebuilding on higher ground.
But there is still time to start curtailing greenhouse gas emissions, he said.
"That's the good news in this story," Deconto said. "This study is suggesting the worst-case scenario might be worse than we were thinking a few years ago, but it still highlights that policy is going to play a really big role in which future path we go down in terms of sea level rise. The horse isn't completely out of the barn yet."
