How much of antarctica is covered in ice

By combining ice movement measurements, seismic data and radar images, the map — dubbed BedMachine Antarctica — revealed previously unknown topographical features, such as the broad ridges that protect the glaciers flowing across the Transantarctic Mountains, which divide East and West Antarctica. That's far deeper than the Dead Sea, the lowest exposed region of land, which sits 1, feet below sea level.

The map is an important resource that will help scientists predict precisely which regions of ice are at greatest risk of sliding into the ocean in the coming decades and centuries, and which sections might be more stable than expected. Despite major progress in the mapping of subglacial geology, significant sections of Antarctica remain unresolved and important spatial details are missing.

Register or Log In. The Magazine Shop. Login Register Stay Curious Subscribe. Planet Earth. Newsletter Sign up for our email newsletter for the latest science news. Sign Up. BedMachine captured the bed topography under the Denman Glacier in Antarctica, colored by the elevation. Areas below sea level are colored in shades of blue while areas above sea level are colored in green, yellow, and brown.

Already a subscriber? However, the response of the ice sheet to global warming is the largest unknown in projecting future sea level over the next to 1, years.

If the weight of the ice were removed it is estimated that the underlying rock would rise on average by 1, m. This process — known as isostatic uplift — would take many tens of thousands of years. Without the ice we would see the single mass of East Antarctica and a smaller archipelago of rugged mountainous islands — West Antarctica. Antarctica has not always been the icy, apparently barren continent it now is. In the distant past it lay in the northern hemisphere.

As recently as 2. Being afloat, ice shelves experience no friction under them, so they tend to flow even more rapidly than ice streams, up to 3km per year. Much of Antarctica is fringed by ice shelves. Ross and Ronne-Filchner ice shelves each have areas greater than the British Isles. Across the base of ice shelves, sea water and ice come into contact. Where this sea water is warm enough, the ice shelf will melt, adding cold fresh water to the sea. This diluted seawater eventually helps to form a water mass called Antarctic Bottom Water which is present in many of the deepest parts of the Southern Ocean.

Eventually, ice breaks off the ice shelves to form icebergs. Ice shelves may be sensitive indicators of climate change and several major ice shelves in the Antarctic Peninsula region have collapsed in recent decades. Beyond the ice shelves is the sea. When the sea freezes it forms a salty type of ice, sea ice. So much of the sea freezes around the continent that in winter, Antarctica almost doubles in size. Although usually only a few metres thick, sea ice insulates the sea and limits the amount of sunlight reaching it.