Washington, Feb 23 (IANS) Floating ice shelves attached to Antarctica are disappearing due to global warming, says a new study, adding that this is especially alarming because the shelves hold together the Antarctic ice sheet that covers nearly 98 percent of the continent.

As the ice shelves break off, it is easier for outlet glaciers and ice streams from the ice sheet to flow into the sea. The transition of that ice from land to the ocean is what raises sea level.

'This research is part of a larger ongoing US Geological Survey (USGS) project that is for the first time studying the entire Antarctic coastline in detail, and this is important because the Antarctic ice sheet contains 91 percent of Earth's glacier ice,' said USGS scientist Jane Ferrigno.

'The loss of ice shelves is evidence of the effects of global warming. We need to be alert and continually understand and observe how our climate system is changing,' said Ferrigno.

Ice shelves are retreating in the southern section of the Antarctic Peninsula due to climate change. This could result in glacier retreat and sea-level rise if warming continues, threatening coastal communities and low-lying islands worldwide.

The peninsula is one of Antarctica's most rapidly changing areas because it is farthest from the South Pole, and its ice shelf loss may be a forecast of changes in other parts of Antarctica and the world if warming continues.

Retreat along the southern part of the peninsula is of particular interest because that area has the peninsula's coolest temperatures, demonstrating that global warming is affecting it along its entire length.

The Antarctic Peninsula's southern section contains five major ice shelves -- Wilkins, George VI, Bach, Stange and the southern portion of Larsen Ice Shelf.

The ice lost since 1998 from the Wilkins ice shelf alone totals more than 4,000 square km.