The icy continent surrounding the South Pole is called Antarctica. This region is larger in area Europe. It is a cold and forbidding land that has no permanent human population and is almost devoid of animal or plant life. However, the oceans adjoining Antarctica teem with life.

The Land

An ice sheet covers nearly all of Antarctica. At its thickest point the ice sheet is 15,670 feet (4,776 meters) deep—almost 3 miles (5 kilometers). It averages 7,000 to 8,000 feet (2,100 to 2,400 meters) thick, making Antarctica the continent with the highest mean elevation. This ice sheet contains 90 percent of the world's ice and 70 percent of the world's fresh water.

The Antarctic ice was formed from the snows of millions of years that fell on the land, layer on layer. The weight of new snow squeezes the old snow underneath until it turns to a substance called firn, then ice. As the ice piles up, it moves toward the coast like batter spreading on a pan. The moving ice forms into glaciers, rivers of ice that flow into the sea. Pieces of the floating glaciers break off from time to time, a process called calving. These icebergs float north until they reach warm water, break into pieces, and melt. Icebergs as large as 40 by 30 miles (64 by 48 kilometers) have been sighted, but most are smaller. In some places the floating glaciers stay attached to the land and continue to grow until they become ice shelves. The Ross Ice Shelf alone is bigger than France and averages 1,000 feet (300 meters) thick.

The Transantarctic Mountains extend across the continent, dividing the ice sheet into two parts. The larger, eastern part rests on land that is mostly above sea level. The sheet has been there at least 14 million years, and scientists doubt that it will ever melt. The smaller, western part is on land that is mostly below sea level. Scientists think that if global warming continues, the western part could melt—perhaps in as little as a one-hundred-year period. The melted ice would raise sea level throughout the world by about 20 feet (6 meters).

Other mountain ranges include the Prince Charles Mountains and smaller ranges near the coasts. The Antarctic Peninsula has many mountains. The Ellsworth Mountains are Antarctica's highest, the Vinson Massif rising 16,066 feet (4,897 meters) above sea level. Mountains with only their peaks showing through the ice (called nunataks) are found in some areas. Several active volcanoes on the continent provide spectacular and scenic landforms at many places and are located near the Antarctic Peninsula and in the Transantarctic Mountains.

About 2 percent of Antarctica is ice-free. These unusual land areas, called oases, generally are near the coast and include the dry valleys of southern Victoria Land and the Bunger Oasis in Wilkes Land. High rims at the end of the valleys prevent entry of large glaciers. The warm local climate melts the ends of smaller glaciers extending into the valleys.

Surrounding Antarctica are the southern parts of the Pacific, the Atlantic, and the Indian oceans. The Antarctic Convergence, which encircles Antarctica roughly 1,000 miles (1,600 kilometers) off the coast, divides the cold southern water masses and the warmer northern waters. The Antarctic Circumpolar Current, the world's largest ocean current, moves eastward around the continent at an average speed of about half a knot (1 kilometer per hour). Sea ice up to 10 feet (3 meters) thick forms outward from the continent every winter, making a belt 300 to 1,000 miles (500 to 1,600 kilometers) wide. Even in summer the sea ice belt is 100 to 500 miles (160 to 800 kilometers) wide in most places.

Antarctica has three points that are called south poles. The best known is the geographic South Pole, at 90° S. latitude on the axis of the Earth's rotation. The geomagnetic south pole is at about 78° S. 110° E., in East Antarctica; it is the center of the Southern Hemisphere auroras. The magnetic south pole is the area toward which compasses point; it is just off the Adélie Coast at about 65° S. 140° E.

Antarctica does not have 24-hour periods broken into days and nights. At the South Pole the sun rises on about September 21 and moves in a circular path upward until December 21, when it reaches about 23.5° above the horizon. Then it circles downward until it sets on about March 22. This “day,” or summer, is six months long. From March 22 until September 21 the South Pole is dark, and Antarctica has its long “night,” or winter.

According to theory, some 200 million years ago Antarctica was joined to South America, Africa, India, and Australia in a single large continent called Gondwanaland. There was no ice sheet, and trees and large animals flourished. Today, only geological formations, coal beds, and fossils remain as clues to Antarctica's warm past.

Climate

Antarctica is the coldest continent. The world's record low temperature of –128.6° F (–89.2° C) was recorded there. The mean annual temperature of the interior is –70° F (–57° C). The coast is warmer. Monthly mean temperatures at McMurdo Station range from –18° F (–28° C) in August to 27° F (–3° C) in January. Along the Antarctic Peninsula temperatures have been as high as 59° F (15° C).

Because it is such a large area of extreme cold, Antarctica plays an important role in global atmospheric circulation. In the tropics the sun warms the air, causing it to rise and move toward the poles. When these air masses arrive over Antarctica, they cool, become heavier, and fall from the high interior of the continent toward the sea, making some Antarctic coasts the windiest places in the world. Winds on the Adélie Coast in the winter of 1912 to 1913 averaged 40 miles (64 kilometers) per hour 64 percent of the time, and gusts of nearly 200 miles (320 kilometers) per hour have been recorded.

Antarctica's interior is one of the world's major cold deserts. Precipitation (if melted) averages only 1 to 2 inches (2.5 to 5 centimeters) a year.

Plant and Animal Life

The severe climate has kept nearly all of Antarctica almost devoid of life. Nevertheless, botanists have found bacteria and yeast growing just 183 miles (295 kilometers) from the geographic South Pole. A lichen was found in a sunny canyon 266 miles (428 kilometers) from the pole, and a blue-green alga in a frozen pond 224 miles (360 kilometers) from the pole. Microbes related to lichens colonize in green and brown layers just beneath the surface of rocks facing the sun. Mosses and liverworts grow in some ice-free areas along the coast. Two species of flowering plants—a grass and an herb—grow on the peninsula.

The native land animals are limited to arthropods (such as insects), of which 76 species have been discovered. Nearly all of the species are found only in Antarctica. These springtails, midges, and mites live generally along the coast among plant colonies. The southernmost known animal, the mite, has been found 315 miles (507 kilometers) from the South Pole.

The immense numbers of birds and seals that live in Antarctica are, properly speaking, sea animals. They spend most of their time in or over the water, where they get their food. These animals come ashore only to establish rookeries and breed.

About 45 species of birds live south of the Antarctic Convergence. Two penguin species—the emperor and the Adélie—are distributed widely around the entire coastline. Gentoo and chinstrap penguins occupy Antarctic Peninsula coasts and some islands. Penguins, fine swimmers, catch their food—mostly krill (a shrimplike animal) and fishes—underwater.

Four species of seals breed almost exclusively in the Antarctic. They are the Weddell seal, which ranges as far south as the sea does and can dive as deep as 2,000 feet (600 meters) for nearly an hour; the crabeater seal, which spends most of its time around pack ice (sea ice); the leopard seal, which favors penguins as its food; and the Ross seal, rarely seen. Other Antarctic species include the fur seal and the huge elephant seal. Most populous is the crabeater, whose numbers are estimated at 50 to 75 million. Leopard and Weddell seals by comparison number only 250,000 to 500,000 each. The others exist in even smaller numbers.

Fishes peculiar to the Antarctic include the Antarctic cod and the icefish. These and other Antarctic fish have developed blood that enables them to live in seawater as cold as 28° F (–2° C).

The most important single member of the Antarctic marine food chain is the krill. This crustacean looks like a small shrimp and exists in huge numbers; one vast swarm stretching several miles in length was observed from ships, and some biologists think the total population may be 5 billion tons or more. Krill eat small marine plants (phytoplankton) and animals (zooplankton) and in turn are eaten in great numbers by squid, birds, seals, and whales.

Economic Development

Antarctica is so far from world markets, and its environment is so hostile, that little economic development has taken place. Also, little is known about the amounts of natural resources that exist there. But, if world shortages of food and energy products become severe enough, Antarctica may be more intensely explored. In anticipation of such a need, 15 nations have signed a convention for the conservation of living marine resources on the Antarctic continent.

The first people to make money by going to Antarctica were whalers and sealers, who first crossed the Antarctic Convergence in 1778. Seal hunters began catching Antarctic seals for their oil and fur in the early 1790s. Fur seals and then elephant seals were reduced almost to extinction by the mid-1800s, at which point the sealers finally stopped their Antarctic hunts. The populations of fur and elephant seals once again are growing.

In 1978 the nations interested in Antarctica agreed to prohibit the taking of fur, elephant, and Ross seals. This pact also limits the annual catch of crabeater, leopard, and Weddell seals. But no seal hunting has taken place in Antarctica since 1964.

Whaling began in Antarctic waters in the 19th century. The industry enlarged greatly in the early 1900s, when steamships, harpoon guns, and shore processing stations (notably at South Georgia) were introduced. During the 1912–13 season 10,760 whales were caught. After that time nearly all the whales caught in the world were caught in Antarctic waters. In 1931, a peak year, 40,199 whales were caught in the Antarctic, while only 1,124 were caught in the rest of the world. So many whales were caught that their numbers declined, just as had those of the seals. The industry declined after 1960. In the 1980–81 season fewer than 6,000 whales were caught in the Antarctic; all were minke whales, a relatively small-sized species also called the lesser rorqual.

Commercial fishing was begun by the Soviet Union in 1967. In 1971 a Soviet fleet of 40 trawlers and support ships in the southern ocean landed an estimated 300,000 tons—mostly cod, herring, and whiting. Today fleets of other nations, mainly Japan and Norway, also fish the waters.

Krill fishing began in the early 1970s, and by 1980 the Soviet Union and Japan were taking about 100,000 tons a year for use as a shrimp substitute and animal feed. Some scientists believe that huge amounts of krill could be harvested from the Antarctic, enough to double the worldwide catch of seafood. But much remains to be learned about the biology and population of krill to know how much damage would be done by huge harvests.

In 1982 the nations that were interested in Antarctica set up a scientific committee to study the Antarctic ecosystem and a commission to set catch limits. The nations wanted to protect the unique ecosystem and to avoid any activities that had already reduced the numbers of whales and seals in the area.

Petroleum and minerals have never been exploited in Antarctica. Minerals have been found in great variety but almost always in small amounts. Large mineral deposits probably exist, but the chances of finding them are small. Manganese nodules on the ocean floor, geothermal energy, coal, petroleum, and natural gas are potential resources that could perhaps be exploited in the future. Only two large mineral deposits have been found: iron ore in the Prince Charles Mountains and coal in the Transantarctic Mountains. But it would cost too much to get these materials to market to make them economically attractive.

Some authorities think that there may be large reserves of oil and natural gas in Antarctica, simply because the continental shelf is so large. However, very little exploration has been done, and even if they are found, extraction will be difficult. The edge of the Antarctic continental shelf is 1,000 to 3,000 feet (300 to 900 meters) deep, much deeper than the world average continental shelf depth of about 600 feet (200 meters), and Antarctica's huge icebergs would threaten drill rigs. Also, the environmental impact of spills would be greater in Antarctica than elsewhere because the low temperatures retard the growth of biological organisms that reduce crude oil to environmentally harmless components.

Some people have devised ingenious schemes for towing Antarctic icebergs north to warm, dry lands as a cheap source of fresh water. But many scientists and engineers believe that an iceberg, even if protected by the best possible means, would break and melt before it got to the place where it would be used.

Commercial tourist visits to Antarctica began in the 1950s. Between 1958 and 1980 an estimated 16,640 passengers on 80 ship cruises visited places along the Antarctic Peninsula and in the Ross Sea. Between 1977 and 1980 airliners from New Zealand and Australia carrying some 11,145 passengers made about 45 sight-seeing flights over portions of the Antarctic continent.

Political and International Relations

Because it has never had permanent human settlements, Antarctica has had an unusual political history. Seven nations have claimed pie-shaped sectors of territory centering on the South Pole. Three of the claimed sectors overlap on the Antarctic Peninsula. One sector is unclaimed. Most other nations do not recognize these claims. The United States policy, for example, is that the mere discovery of lands does not support a valid claim unless the discovery is followed by actual settlement. Also, like many other nations, the United States reserves all rights resulting from its explorations and discoveries.

This unsettled situation might have continued had it not been for a surge of scientific interest in Antarctica that developed in the middle 1950s. At that time scientists of 12 nations decided to make research in Antarctica the major portion of a large investigation, the International Geophysical Year. The 12 nations were Argentina, Australia, Belgium, Chile, France, Japan, New Zealand, Norway, South Africa, the United Kingdom, the United States, and the Soviet Union. When this program was completed in 1958, these nations decided to continue their research programs in Antarctica.

Much of the research had been achieved through international cooperation, and the 12 nations carried their new, friendly ties from science into politics. They met in Washington, D.C., in 1959 to write the Antarctic Treaty. The treaty reserves the region for peaceful purposes, especially scientific research. It prohibits nuclear weapons and disposal of radioactive waste, and it does not allow military activities except to support science and other peaceful pursuits. The treaty does not recognize or dispute the territorial claims of any nation, but it also does not allow any new claims to be made. It allows members to inspect each others' installations, encourages the exchange of personnel, and requires each nation to report to the others on its plans and results.

The treaty does not include anything about sharing Antarctica's natural resources, but it does provide for meetings every other year to further its objectives. At these meetings the treaty nations have agreed on conservation plans and on responsible collection and sharing of resources. Other nations later joined the Antarctic Treaty, and by 1982 there were 26 that had signed it.

Scientific Research

Every year about a dozen nations send scientists to Antarctica to do research. In the Antarctic summer about 2,500 people are in the region for this work. They operate research stations and camps; travel in airplanes, helicopters, and snowmobiles to the areas that they need to study; and operate ships for resupply and oceanic research. In winter fewer than 1,000 people remain to operate about 30 research stations scattered around the continent. The winter inhabitants are isolated for several months at a time because it is too cold for anyone to get to them, even in airplanes. Biologists, geologists, oceanographers, physicists, astronomers, glaciologists, and meteorologists conduct experiments here that cannot be duplicated anywhere else. In the 1970s researchers began taking measurements of the protective ozone layer in the atmosphere over Antarctica. A seasonal hole (thinning) was reported over the region in 1985. By the 1990s the ozone depletion had reached alarming proportions and the effects had spread beyond Antarctica.

Exploration and History

The first expedition to come close to Antarctica took place from 1772 through 1775. The English navigator James Cook sailed around the continent and came within 100 miles (160 kilometers) of it. Land was seen in about 1820, when British and United States seal hunters and a Russian exploring expedition reached the Antarctic Peninsula. In the Antarctic summer of 1839–40 a United States Navy expedition headed by Charles Wilkes mapped 1,500 miles (2,400 kilometers) along the coast of East Antarctica. The next summer James Clark Ross of Great Britain sailed into the Ross Sea, traveling as far south as a ship can go. The first recorded landing on Antarctica was on Cape Adare in 1895, and the first group to spend a winter on the continent did so at Cape Adare during the period from March 1898 to March 1899.

The struggle inland and toward the geographic South Pole began with the first expedition by Robert F. Scott of Great Britain in 1901–04. But the first person to reach the pole was Roald Amundsen of Norway on Dec. 14, 1911. On another Antarctic expedition Scott arrived at the pole just a month later; he died on March 29, 1912, trying to return to the coast.

These early expeditions relied on sail power, dog power, and human power for their transportation. The mechanical age arrived on Nov. 26, 1928, when George Hubert Wilkins, leading an American expedition, made an airplane flight from Deception Island. On Nov. 29, 1929, Richard E. Byrd of the United States flew a three-motor Ford plane over the South Pole. Byrd also explored parts of Antarctica by air and on the surface in 1933–35 and 1939–41 and commanded the largest single expedition ever made to Antarctica—the United States Navy's Operation High Jump in 1946–47. Thirteen ships, many airplanes and helicopters, and thousands of men made surveys almost all the way around the continent. In 1990 a six-man international expedition led by an American named Will Steger completed a 221-day trek across Antarctica from west to east using dogsleds. At more than 3,700 miles (6,000 kilometers), it was the longest dogsled trek, as well as the first unmechanized passage through the South Pole. The team members were from the United States, the Soviet Union, France, China, Japan, and Great Britain.

The International Geophysical Year (IGY), 1957–58, was a major scientific effort that established 50 year-round stations, including one at the geographic South Pole and one at the south geomagnetic pole. In 1988 the IGY nations that had signed the Antarctic Treaty agreed on a convention to permit strictly controlled mining in Antarctica—probably by the end of the 20th century. There are no known mineral deposits of value, however, and the harsh climate does not encourage offshore oil exploration. Both the Antarctic Treaty and the new convention avoided the issue of sovereignty, claimed by seven nations over various parts of the region. (See also Polar Exploration.)