A view of the leading edge of the remaining part of the Larsen B ice shelf that extends into the northwest part of the Weddell Sea is seen in this handout photo taken on March 4, 2008. REUTERS/Mariano Caravaca/Handout

WASHINGTON (Reuters) - One Antarctic ice shelf has quickly vanished, another is disappearing and glaciers are melting faster than anyone thought due to climate change, U.S. and British government researchers reported on Friday.

They said the Wordie Ice Shelf, which had been disintegrating since the 1960s, is gone and the northern part of the Larsen Ice Shelf no longer exists. More than 3,200 square miles (8,300 square km) have broken off from the Larsen shelf since 1986.

Climate change is to blame, according to the report from the U.S. Geological Survey and the British Antarctic Survey, available at pubs.usgs.gov/imap/2600/B.

“The rapid retreat of glaciers there demonstrates once again the profound effects our planet is already experiencing -- more rapidly than previously known -- as a consequence of climate change,” U.S. Interior Secretary Ken Salazar said in a statement.

“This continued and often significant glacier retreat is a wakeup call that change is happening ... and we need to be prepared,” USGS glaciologist Jane Ferrigno, who led the Antarctica study, said in a statement.

“Antarctica is of special interest because it holds an estimated 91 percent of the Earth’s glacier volume, and change anywhere in the ice sheet poses significant hazards to society,” she said.

In another report published in the journal Geophysical Letters, the National Oceanic and Atmospheric Administration reports that ice is melting much more rapidly than expected in the Arctic as well, based on new computer analyses and recent ice measurements.

The U.N. Climate Panel projects that world atmospheric temperature will rise by between 1.8 and 4.0 degrees Celsius because of emissions of greenhouse gases that could bring floods, droughts, heat waves and more powerful storms.

As glaciers and ice sheets melt, they can raise overall ocean levels and swamp low-lying areas.