Changes

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 and 70 percent of its fresh water.  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.