Changes

Antarctica is composed of two major, geologically distinct parts bridged by a vast ice sheet. East Antarctica, the larger of the two, is roughly the size of the U.S. and is composed of continental crust covered by an ice sheet that averages 1.6 miles thick. Rock exposures are limited to isolated coastal regions and to alpine elevations in the 2,000-mile long Transantarctic Mountains. West Antarctica, the smaller portion, is a mosaic of small blocks of continental crust covered by the West Antarctic Ice Sheet and an Andean-like mountain chain forming the Antarctic Peninsula. Most of the West Antarctic Ice Sheet is grounded below sea level, in places over 1.5 miles below sea level.

Antarctica is composed of two major, geologically distinct parts bridged by a vast ice sheet. East Antarctica, the larger of the two, is roughly the size of the U.S. and is composed of continental crust covered by an ice sheet that averages 1.6 miles thick. Rock exposures are limited to isolated coastal regions and to alpine elevations in the 2,000-mile long Transantarctic Mountains. West Antarctica, the smaller portion, is a mosaic of small blocks of continental crust covered by the West Antarctic Ice Sheet and an Andean-like mountain chain forming the Antarctic Peninsula. Most of the West Antarctic Ice Sheet is grounded below sea level, in places over 1.5 miles below sea level.

The continent itself is depressed more than half-a-mile to near sea level under the tremendous load of the ice sheet, with some regions well below sea level. The highest mountains rise to elevations of over 14,000 ft. about the height of the U.S. Rocky Mountains.

The continent itself is depressed more than half-a-mile to near sea level under the tremendous load of the ice sheet, with some regions well below sea level. The highest mountains rise to elevations of over 14,000 ft. about the height of the U.S. Rocky Mountains.

The present Antarctic ice sheet accounts for 90 percent of Earth's total ice volume.  The ice sheet at the Pole, nearly two miles thick, is constantly shifting, carrying the Amundsen/Scott Research Facility at the Pole along with it at the rate of about 30 feet a year. Nearly 90 percent of the ice flowing across West Antarctica converges into ice streams that are the most dynamic, and perhaps unstable, components of the ice sheet. Recent glaciological observations have yielded evidence that some of these West Antarctic ice streams may be responding to climatic and sea level changes of the recent past, changes that could lead to more rapid retreat and global sea-level rise in the future. A few active volcanoes may also affect the ice sheet's behavior.

The present Antarctic ice sheet accounts for 90 percent of Earth's total ice volume.  The ice sheet at the Pole, nearly two miles thick, is constantly shifting, carrying the Amundsen/Scott Research Facility at the Pole along with it at the rate of about 30 feet a year. Nearly 90 percent of the ice flowing across West Antarctica converges into ice streams that are the most dynamic, and perhaps unstable, components of the ice sheet. Recent glaciological observations have yielded evidence that some of these West Antarctic ice streams may be responding to climatic and sea level changes of the recent past, changes that could lead to more rapid retreat and global sea-level rise in the future. A few active volcanoes may also affect the ice sheet's behavior.

The Antarctic climate offers a formidable challenge to those who venture there in quest of scientific knowledge. It is the coldest, driest, highest (on average) and windiest continent on Earth. Absolute humidity is lower than on the Sahara. Annual snowfall in much of the interior is less than two inches. Winds that flow down the surface of the ice sheet toward the coast (katabatic winds) commonly reach speeds of 80 miles per hour, and maximum measured wind speeds have exceeded 180 miles per hour. Changes in the weather are dramatic: winds shift from calm to full-gale in a brief period of time. A drop of 65°F was once recorded in 12 minutes. Earth's lowest surface temperature (-126.9°F) was recorded at Russia's Vostok Station in the interior of Antarctica. Coastal locations in summer occasionally rise above the freezing point.

The Antarctic climate offers a formidable challenge to those who venture there in quest of scientific knowledge. It is the coldest, driest, highest (on average) and windiest continent on Earth. Absolute humidity is lower than on the Sahara. Annual snowfall in much of the interior is less than two inches. Winds that flow down the surface of the ice sheet toward the coast (katabatic winds) commonly reach speeds of 80 miles per hour, and maximum measured wind speeds have exceeded 180 miles per hour. Changes in the weather are dramatic: winds shift from calm to full-gale in a brief period of time. A drop of 65 °F was once recorded in 12 minutes. Earth's lowest surface temperature (-126.9 °F) was recorded at Russia's Vostok Station in the interior of Antarctica. Coastal locations in summer occasionally rise above the freezing point.

A lake (Lake Vostok) buried 11,000 ft. under the ice is the size of North America's Lake Huron.

A lake (Lake Vostok) buried 11,000 ft. under the ice is the size of North America's Lake Huron.

Offshore cyclones occur with little warning. Winds typically reach hurricane strength within an hour and persist for several days. A concentration of storm formation and/or intensification occurs at approximately 50°S latitude and is associated with some of the most violent seas in the world ("the roaring forties"). The stretch of ocean between Antarctica and the tip of South America is considered the most hostile in the world and has claimed numerous ships over the centuries.

Offshore cyclones occur with little warning. Winds typically reach hurricane strength within an hour and persist for several days. A concentration of storm formation and/or intensification occurs at approximately 50°S latitude and is associated with some of the most violent seas in the world ("the roaring forties"). The stretch of ocean between Antarctica and the tip of South America is considered the most hostile in the world and has claimed numerous ships over the centuries.

Four species of seals breed almost exclusively in the Antarctic: the Weddell, crabeater, leopard, and Ross. Other species include the fur seal and the huge elephant seal. Most populous is the crabeater, estimated at 50 million to 75 million. Leopard and Weddell seals number 250,000 to 500,000 each.

Four species of seals breed almost exclusively in the Antarctic: the Weddell, crabeater, leopard, and Ross. Other species include the fur seal and the huge elephant seal. Most populous is the crabeater, estimated at 50 million to 75 million. Leopard and Weddell seals number 250,000 to 500,000 each.

Fishes peculiar to the Antarctic include the Antarctic cod and the icefish. These and other fishes have developed proteins in their blood that enable them to live in sea water as cold as 28°F that is, below the freezing temperature of fresh water. There is abundant and varied bottom life (starfish, urchins, shellfish) in most coastal waters.

Fishes peculiar to the Antarctic include the Antarctic cod and the icefish. These and other fishes have developed proteins in their blood that enable them to live in sea water as cold as 28 °F that is, below the freezing temperature of fresh water. There is abundant and varied bottom life (starfish, urchins, shellfish) in most coastal waters.

Aside from phytoplankton (marine plants), a singularly important member of the Antarctic marine food chain is krill. This crustacean looks like a small shrimp and exists in huge numbers; vast swarms stretching several miles in length have been observed from ships, and some biologists believe the krill population may exceed 5 billion tons. Krill eat phytoplankton and small marine animals and in turn are eaten in great numbers by squid, birds, seals, and whales. There is evidence that depletion of the ozone layer affects phytoplankton productivity, and may therefore affect krill and the entire southern ocean food chain.

Aside from phytoplankton (marine plants), a singularly important member of the Antarctic marine food chain is krill. This crustacean looks like a small shrimp and exists in huge numbers; vast swarms stretching several miles in length have been observed from ships, and some biologists believe the krill population may exceed 5 billion tons. Krill eat phytoplankton and small marine animals and in turn are eaten in great numbers by squid, birds, seals, and whales. There is evidence that depletion of the ozone layer affects phytoplankton productivity, and may therefore affect krill and the entire southern ocean food chain.

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 1912-1913 season 10,760 whales were caught. After that time nearly all the whales caught in the world were taken in Antarctic waters. In 1931, the peak year, 40,199 whales were caught in the Antarctic, while 1,124 were caught in the rest of the world. The whaling industry declined after 1960. In the 1980-1981 season fewer than 6,000 whales were caught in the Antarctic; all were Minke whales, a relatively small-sized species. In 1994 the member nations of the International Whaling Commission declared Antarctic waters a whale sanctuary in which no commercial whaling is allowed.

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 1912-1913 season 10,760 whales were caught. After that time nearly all the whales caught in the world were taken in Antarctic waters. In 1931, the peak year, 40,199 whales were caught in the Antarctic, while 1,124 were caught in the rest of the world. The whaling industry declined after 1960. In the 1980-1981 season fewer than 6,000 whales were caught in the Antarctic; all were Minke whales, a relatively small-sized species. In 1994 the member nations of the International Whaling Commission declared Antarctic waters a whale sanctuary in which no commercial whaling is allowed.

====International Geophysical Year====  

====International Geophysical Year====

The IGY, 1 July 1957 to 31 December 1958, was a cooperative endeavor by scientists throughout the world to improve their understanding of the Earth and its environment. Much of the field activity took place in Antarctica, where 12 nations established some 60 research stations. Laurence M. Gould, who was Richard E. Byrd's chief scientist in Antarctica in the 1920s and 1930s and later chaired the National Academy of Sciences Polar Research Board and served on the National Science Board, called the IGY the most comprehensive scientific program ever undertaken and the first attempt at a total study of the environment. "No field of geophysics," he wrote in 1958, "can be understood or complete without specific data available only from this vast continent and its surrounding oceans."

The IGY, 1 July 1957 to 31 December 1958, was a cooperative endeavor by scientists throughout the world to improve their understanding of the Earth and its environment. Much of the field activity took place in Antarctica, where 12 nations established some 60 research stations. Laurence M. Gould, who was Richard E. Byrd's chief scientist in Antarctica in the 1920s and 1930s and later chaired the National Academy of Sciences Polar Research Board and served on the National Science Board, called the IGY the most comprehensive scientific program ever undertaken and the first attempt at a total study of the environment. "No field of geophysics," he wrote in 1958, "can be understood or complete without specific data available only from this vast continent and its surrounding oceans."

The U.S. established six Antarctic IGY research stations: Little America (on the Ross Ice Shelf), Hallett (in Victoria Land), South Pole and Byrd (in Marie Byrd Land), plus Wilkes (on the coast of Wilkes Land, East Antarctica) and Ellsworth (on the Filchner Ice Shelf). Naval Air Facility, McMurdo Sound (now McMurdo Station), was set up as a logistics base from which to supply South Pole. Studies were directed toward geophysics and upper atmospheric physics and complemented simultaneous observations around the globe. Long traverses were made to collect data in glaciology, seismology, gravimetry, and meteorology. Geological and biological samples were also collected, although these disciplines were not formally part of the IGY.

The U.S. established six Antarctic IGY research stations: Little America (on the Ross Ice Shelf), Hallett (in Victoria Land), South Pole and Byrd (in Marie Byrd Land), plus Wilkes (on the coast of Wilkes Land, East Antarctica) and Ellsworth (on the Filchner Ice Shelf). Naval Air Facility, McMurdo Sound (now McMurdo Station), was set up as a logistics base from which to supply South Pole. Studies were directed toward geophysics and upper atmospheric physics and complemented simultaneous observations around the globe. Long traverses were made to collect data in glaciology, seismology, gravimetry, and meteorology. Geological and biological samples were also collected, although these disciplines were not formally part of the IGY.

====Antarctic Treaty of 1959====  

====Antarctic Treaty of 1959====

International cooperation in the IGY stimulated the Antarctic Treaty [http://www.state.gov/t/ac/trt/4700.htm], signed by the 12 Antarctic IGY nations at Washington, D.C., in 1959 and entered into force in 1961. The treaty establishes a legal framework for the area south of 60°S, which includes all of Antarctica. There are two types of Antarctic Treaty parties. Consultative nations, now 26 in number, are empowered to meet periodically and to influence operation of the treaty. Acceding nations, of which there now are 17, agree to abide by the treaty, but, not being among the original signatories and not having substantial programs in Antarctica, do not participate in the consultative process.

International cooperation in the IGY stimulated the Antarctic Treaty [http://www.state.gov/t/ac/trt/4700.htm], signed by the 12 Antarctic IGY nations at Washington, D.C., in 1959 and entered into force in 1961. The treaty establishes a legal framework for the area south of 60°S, which includes all of Antarctica. There are two types of Antarctic Treaty parties. Consultative nations, now 26 in number, are empowered to meet periodically and to influence operation of the treaty. Acceding nations, of which there now are 17, agree to abide by the treaty, but, not being among the original signatories and not having substantial programs in Antarctica, do not participate in the consultative process.