PARIS, France—The East Antarctic ice sheet, once seen as largely unaffected by global warming, has lost billions of tons of ice since 2006 and could boost sea levels in the future, according to a new study.

Published Sunday in Nature Geoscience, the same study shows that the smaller but less stable West Antarctic ice sheet is also shedding significant mass.

Scientists worry that rising global temperatures could trigger a rapid disintegration of West Antarctica, which holds enough frozen water to push up the global ocean watermark by about five meters (16 feet).

University of Texas professor Jianli Chen and colleagues analyzed nearly seven years of data on the ocean-ice sheet interaction.

Covering the period up January 2009, the data was collected by the twin GRACE satellites, which detects mass flows in the ocean and polar regions by measuring changes in Earth's gravity field.

Consistent with earlier research, they found that West Antarctica dumped, on average, about 132 billion tons of ice into the sea each year, give or take 26 billion tons.

They also found for the first time that East Antarctica is likewise losing mass, mostly in coastal regions, at a rate of about 57 billion tons annually.

The margin or error, they cautioned, is almost as large as the estimate, meaning ice loss could be a little as a few billion tons or more than 100.

Up to now, scientists had thought that East Antarctica was in "balance," meaning that it accumulated as much mass and it gave off, perhaps a bit more.

"Acceleration of ice loss in recent years over the entire continent is thus indicated," the authors conclude.

"Antarctica may soon be contributing significantly more to global sea level rise."

Another study published last week reported higher-than-expected increases in Antarctic temperatures during prior "interglacials," warm periods such as our own that have occurred roughly every 100,000 years.

During the last interglacial some 128,000 years ago, called the Eemian Period, temperatures in the region were probably six degree Celsius (10.8 degrees Fahrenheit) higher than today, which is about 3 C (5.4 C) above previous estimates, the study said.

The findings suggest that the region may be more sensitive than scientists thought to greenhouse gas concentrations in the atmosphere that were roughly equivalent to present day levels.

During the Eemian, sea levels were five-to-seven meters higher than today.