Antarctica is a large continent at the Earth's south pole that is almost completely covered by an immense ice sheet thousands of metres thick.
The Antarctic ice sheet holds about 90% of the fresh water that is present on the planet's surface, according to the British Antarctic Survey. The interior of the continent is extremely dry with only small amounts of annual snowfall, making much of Antarctica a desert.
Although Antarctica is the coldest place on Earth, rapidly rising surface temperatures and melting ice are being studied intensely by scientists around the world so they can better understand the link between their observations and the climate change caused by humans.
Image: The Barne Glacier meets the Antarctic coastal sea ice (credit: George Steinmetz/SPL)
Antarctica
Antarctic freeze
Elapsed time and satellite imagery show the Antarctic doubling in size.
Usually, elapsed time sequences dissolve between two images taken at a specific interval. In this instance, the cameraman returned every few months to a fixed post where he recorded moving images with a 35mm camera, creating the continuous dissolve as the sea ice grows. The combination with NASA satellite imagery from space gives context to the immense change that results from the winter ice growth.
Shrinking glaciers
Many of the world's glaciers are retreating.
Dr Iain Stewart describes the retreat of many of the Earth's glaciers and the break up of polar ice sheets.
Antarctica's wonders
Technology reveals secrets below the polar ice.
Dr Iain Stewart examines some of the secrets buried deep below the Antarctic ice and marvels at the other wonders of the polar ice.
Bleak continent
Antarctica can be drier than the Sahara yet algae still survives.
Antarctica can be drier than the Sahara yet algae still survives.
Antarctica (i/æntˈɑrtɨkə/ or /ænˈtɑrktɨkə/)[Note 1] is Earth's southernmost continent, containing the geographic South Pole. It is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14.0 million km2 (5.4 million sq mi), it is the fifth-largest continent in area after Asia, Africa, North America, and South America. For comparison, Antarctica is nearly twice the size of Australia. About 98% of Antarctica is covered by ice that averages at least 1 mile (1.6 km) in thickness.
Antarctica, on average, is the coldest, driest, and windiest continent, and has the highest average elevation of all the continents. Antarctica is considered a desert, with annual precipitation of only 200 mm (8 inches) along the coast and far less inland. The temperature in Antarctica has reached −89 °C (−129 °F). There are no permanent human residents, but anywhere from 1,000 to 5,000 people reside throughout the year at the research stations scattered across the continent. Only cold-adapted organisms survive there, including many types of algae, animals (for example mites, nematodes, penguins, seals and tardigrades), bacteria, fungi, plants, and protista. Vegetation where it occurs is tundra.
Although myths and speculation about a Terra Australis ("Southern Land") date back to antiquity, the first confirmed sighting of the continent is commonly accepted to have occurred in 1820 by the Russian expedition of Fabian Gottlieb von Bellingshausen and Mikhail Lazarev on Vostok and Mirny. The continent, however, remained largely neglected for the rest of the 19th century because of its hostile environment, lack of resources, and isolation. The Antarctic Treaty was signed in 1959 by 12 countries; to date, 49 countries have signed the treaty. The treaty prohibits military activities and mineral mining, prohibits nuclear explosions and nuclear waste disposal, supports scientific research, and protects the continent's ecozone. Ongoing experiments are conducted by more than 4,000 scientists from many nations.
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