The melting of glaciers in Antarctica because of global warming may push up sea levels faster than previously believed, potentially threatening coastal cities including Tokyo, New York and Shanghai, researchers in Germany said.
Antarctica's ice discharge may raise sea levels as much as 37 centimeters (14.6 inches) this century if the output of greenhouse gases continues to grow, according to a study led by the Potsdam Institute for Climate Impact Research. The increase may be as little as 1 centimeter, they said.
"This is a big range, which is exactly why we call it a risk," Anders Levermann, the study's lead author, said in a statement. "Science needs to be clear about the uncertainty so that decision makers at the coast and in coastal mega-cities can consider the implications in their planning processes."
NASA estimates the glaciers in the Amundsen Sea region contain enough water to raise global sea levels by 4 feet (1.2 meters), and in May said the glacier melt may have become "unstoppable."
The Potsdam institute's projections for this century's sea-level contribution are "significantly higher" than the latest upper-end projections from the Intergovernmental Panel on Climate Change, it said.
"Earlier research indicated that Antarctica would become important in the long term," Levermann said. "But pulling together all the evidence, it seems that Antarctica could become the dominant cause of sea level rise much sooner."