6 minute read

Antarctica

Current Events

A wide variety of research is continuing on Antarctica, primarily during the relatively warmer summer months from October to February when temperatures may reach a balmy 30–50°F ( -1–10°C). The cold temperatures and high altitude of Antarctica allow astronomers to put their telescopes above the lower atmosphere, which lessens blurring. During the summer months, they can study the Sun around the clock, because it shines 24 hours a day. Antarctica is also the best place to study interactions between solar wind and Earth's magnetic field, temperature circulation in the oceans, unique animal life, ozone depletion, ice-zone ecosystems, and glacial history. Buried deep in Antarcti ca's ice lie clues to ancient climates, which may provide answers to whether the earth is due for global warming or the next ice age.

Scientists consider Antarctica to be a planetary bellwether, an early indicator of negative changes in the entire planet's health. For example, they have discovered that a hole is developing in the ozone layer over the continent, a protective layer of gas in the upper atmosphere that screens out the ultraviolet light that is harmful to all life on Earth. The ozone hole was first observed in 1980 during the spring and summer months, from September through November. Each year, greater destruction of the layer has been observed during these months, and the first four years of the 1990s have produced the greatest rates of depletion thus far. The hole was measured to be about the size of the continental United States in 1994, and it lasts for longer intervals each year. Scientists have identified various chemicals created and used by humans, such as chlorofluorocarbons (CFCs), as the cause of this destruction, and bans on uses of these chemicals have begun in some countries.

Researchers have also determined that a major climate change may have occurred in Antarctica in the 1980s and 1990s, based on recorded changes in ozone levels and an increase in cloudiness over the South Pole. This, coupled with a recorded weakening of the ozone shield over North America in 1991, has led scientists to conclude that the ozone layer is weakening around the entire planet.

Others are studying the ice cap on Antarctica to determine if, in fact, the earth's climate is warming due to the burning of fossil fuels. The global warming hypothesis is based on the atmospheric process known as the greenhouse effect, in which pollution prevents the heat energy of the earth from escaping into the outer atmosphere. Global warming could cause some of the ice cap to melt, flooding many cities and lowland areas. Because the polar regions are the engines that drive the world's weather system, this research is essential to identify the effect of human activity on these regions.

Most recently, a growing body of evidence is showing that the continent's ice has fluctuated dramatically in the past few million years, vanishing completely from the continent once and from its western third at least several times. These collapses in the ice structure might be triggered by climatic change, such as global warming, or by far less predictable factors, such as volcanic eruptions under the ice. While the east Antarctic ice sheet has remained relatively stable because it lies on a single tectonic plate, the western ice sheet is a jumble of small plates whose erratic behavior has been charted through satellite data. The west Antarctic is also dominated by two seas, the Ross and Weddell, whose landward regions are covered by thick, floating shelves of ice. Some researchers speculate that if warmer, rising oceans were to melt this ice, the entire western sheet might disintegrate quickly, pushing global sea levels up by 15-20 ft (5-6 m).

Resources

Books

Anderson, J. B. Antarctic Marine Geology. Cambridge: Cambridge University Press, 1999.

Billings, Henry. Antarctica—Enchantment of the World. Chicago: Childrens Press, 1994.

Hancock P. L. and Skinner B. J., eds. The Oxford Companion to the Earth. Oxford: Oxford University Press, 2000.

Hurley, Frank. South with Endurance: Shackleton's Antarctic Expedition, 1914-1917. New York: Simon & Schuster, 2001.

Joughin, I. "Antarctica: A Review of Recent Medical Research." Trends in Pharmacological Sciences. 23, no. 10 (2002): 487-490.

McGonigal, David. Lynn Woodworth, and Sir Edmund Hillary, eds. Antarctica and the Arctic: The Complete Encyclopedia. Westport, CT: Firefly Books, 2001.


Periodicals

Grotta, Daniel and Sally. "Antarctica: Whose Continent is it Anyway?" Popular Science 240, no. 1 (1992): 62-7, 90-1.

Horgan, John. "Antarctic Meltdown." Scientific American 266, no. 3: 19-28.

Keeling, Ralph F. "Palaeoceanography: Antarctic Stratification and Glacial CO2." Nature 412, no. 6847 (2001): 605-606.

Kiernan, K. "Impacts of Geoscience Research on the Physical Environment of the Antarctic." Australian Journal of Earth Sciences 48, no. 5 (2001): 767.

Monastersky, Richard. "Antarctic Ozone Level Reaches New Low." Science News 144, no. 16: 247.

Monastersky, Richard. "Science on Ice." Science News 143, no. 15 (1993): 232-35.

Palca, Joseph. "Poles Apart, Science Thrives on Thin Ice." Science 255, no. 5042 (1992): 276-78.


Sally Cole-Misch

KEY TERMS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Antarctic Circle

—The line of latitude at 66 degrees 32 minutes South, where there are 24 hours of daylight in midsummer and 24 hours of darkness in midwinter.

Antarctic convergence

—A 25-mi (40-km) region where cold Antarctic surface water meets warmer, subantarctic water and sinks below it.

Antarctic Ocean

—The seas surrounding the continent, where the Atlantic, Pacific, and Indian Oceans converge.

Blubber

—Whale or seal fat used to create fuel.

Calving

—The process in which huge chunks of ice or icebergs break off from ice shelves and sheets or glaciers to form icebergs.

Dry valleys

—Areas on the continent where no rain is known to have fallen for more than two million years, and the extremely dry katabatic winds cause any snow blown into the valleys to evaporate before hitting the ground. The Taylor, Victoria, and Wright valleys are the largest continuous areas of ice-free land on the continent.

Glacier

—A river of ice that moves down a valley to the sea, where it breaks into icebergs.

Iceberg

—A large piece of floating ice that has broken off a glacier, ice sheet, or ice shelf.

Katabatic winds

—Fierce, dry winds that flow down along the steep slopes of the interior mountains of Antarctica, and along ice caps and glaciers on the subantarctic islands.

Krill

—Tiny sea animals or zooplankton that are the main food for most larger species in the Antarctic region.

Nunataks

—Mountain peaks that are visible above the ice and snow cover.

Pack ice

—Ice from seawater, which forms a belt approximately 300–1,800 mi (483–2,897 km) wide around the continent in winter.

South magnetic pole

—The point to which a compass is attracted and which is some distance from the geographic South Pole. It varies from year to year as the earth's magnetic field changes.

South pole

—The geographically southernmost place on Earth.

Southern lights

—Also known as the aurora australis, they are streamers of different colors in the sky, especially at night, and are thought to be caused by electrical disturbances and cosmic particles in the upper atmosphere that are attracted by the South Magnetic Pole.

Subantarctica

—The region just north of Antarctica and the Antarctic Circle, but south of Australia, South America, and Africa.

Additional topics

Science EncyclopediaScience & Philosophy: Ambiguity - Ambiguity to Anticolonialism in Middle East - Ottoman Empire And The Mandate SystemAntarctica - Antarctica—an Overview, Geology, Climate, Plants And Animals, Exploration Of The Continent, Scientific Exploration