NOVA Online | Warnings from the Ice

Antarctic Almanac

Photo of iceberg

Ice

Antarctica has some seven million cubic miles of ice, representing some 90 percent of the world's total.
The ice averages one and a half miles in thickness, with the thickest ice being almost three miles thick.
Antarctica's ice is so heavy that it compresses the land surface over much of the continent to below sea level. The ice is so heavy, in fact, that it deforms the South Pole, making the Earth slightly pear-shaped.
At depths of 10,000 feet, the weight of the ice is some 30 tons per square foot.
In winter, the sea ice around Antarctica grows at the rate of 40,000 square miles a day. It effectively doubles the size of the continent, from seven million square miles to 13 million square miles.
The polar ice cap around the South Pole advances about 33 feet annually.
The Lambert Glacier in East Antarctica, the world's largest valley glacier, discharges some 8.4 cubic miles of ice into the Avery Ice Sheet every year.
The largest iceberg ever spotted was sighted by the USS Glacier on November 12, 1956. It measured 208 miles long by 60 miles wide—the size of Belgium.

Land

Antarctica is the highest, driest, coldest, and windiest continent.
Only about two percent of the Antarctic continent pokes through the ice cover.
Antarctica is as large as the United States and Mexico combined.
The Transantarctic Mountain range, which separates East and West Antarctica, is one of the world's great mountain ranges, stretching a full 3,000 miles—the width of the continental U.S.
Mount Vinson, Antarctica's highest mountain at 16,600 feet, was discovered only in 1958 by U.S. Navy Aircraft.
The lowest point on the continent is the Bentley Subglacial Trench, which is 8,325 feet below sea level.
Annual mean temperature over the elevated central plateau is between -58°F and -76°F.
The lowest temperature ever recorded was measured at the Russian Vostok station in 1983: -129°F

Water

Despite containing 70 percent of the world's freshwater, much of Antarctica is a desert, with the annual snow accumulation over much of East Antarctica being the equivalent of less than two inches of rainfall.
The only river of any size in Antarctica is the Onyx River, which arises from a coastal glacier every summer and flows inland for some 20 miles, replenishing one of the few lakes, Lake Vanda.
The Antarctic Circumpolar Current is the only current to sweep all the way around the world without being stopped by a continent.
If the West Antarctic ice sheet were to melt, global seas would rise by 15 to 20 feet. If the East sheet were to melt as well, seas would rise by as much as 200 feet, swamping many oceanic islands and redrawing the world's coastlines (see Water World).

Wildlife

Antarctica's largest land animal is a wingless midge (Belgica antarctica), which grows to half an inch long. The largest land predator is a mite that weighs only 100 micrograms.
Antarctica has just two native flowering plants, Deschampsia antarctica (a grass) and Colobenthos subulatus (a pearlwort).
One of four fossil penguins found in Antarctica would have stood four feet 11 inches tall when alive.
Of some 20,000 fish species, only about 120 swim in Antarctic waters.
Some polar fish have an assortment of glycopeptides, or antifreeze molecules, in their body fluids, allowing those fluids to remain liquid below the temperature at which ice forms.

Glossary

Antarctica has a lexicon all its own. Here's a sampling:

growler: a hard-to-see iceberg, often awash with seawater, that poses a hazard to ships
katabatic: cold, dense wind blowing by force of gravity off the high central plateau toward the coasts
névé: literally "last year's snow," consolidated snow deep within an ice sheet that is one step away from being solid glacial ice
nilas: a thin sheen of ice on the sea surface that bends but does not break with wave action
nunatak: any mountain poking through the ice blanket
polynya: a stretch of open water within an expanse of pack ice that remains open throughout the winter
satsrugi: irregularly shaped heaps of snow on the surface of the ice sheet, fashioned by wind
ventifact: wind-blasted, curiously shaped rocks found in the Dry Valleys of Antarctica