World oceans rising dangerously, says NASA

Washington: Oceans around the world are rising dangerously, warns NASA, adding that the ramifications of sea level rise can be even scarier than the worst-case scenarios predicted by climate models.

Seas around the world have risen on an average of nearly three inches since 1992, with some locations rising more than nine inches due to natural variation, according to the latest satellite measurements from NASA and its partners.

In 2013, the United Nations Intergovernmental Panel on Climate Change (IPCC) issued an assessment based on a consensus of international researchers that stated global sea levels would likely rise from 1 to 3 feet by the end of the century, a NASA statement read.

Scientists estimate that about one-third of sea level rise is caused by expansion of warmer ocean water; one-third is due to ice loss from the massive Greenland and Antarctic ice sheets, and the remaining third results from melting mountain glaciers.

But the fate of the polar ice sheets could change that ratio and produce more rapid increases in the coming decades. The Greenland ice sheet, covering 660,000 square miles -- nearly the area of Alaska -- shed an average of 303 gigatons of ice a year over the past decade, according to satellite measurements.

The Antarctic ice sheet, covering 5.4 million square miles - larger than the US and India combined -- has lost an average of 118 gigatons a year. Although Antarctica’s contribution to sea level rise is currently much smaller than that of Greenland, recent research indicates this could change in the upcoming century.