Polar Ice Caps

The polar ice caps cover the north and south poles and their surrounding territory, including the entire continent of Antarctica in the south, the Arctic Ocean, the northern part of Greenland, parts of northern Canada, and bits of Siberia and Scandinavia also in the north. Polar ice caps are dome-shaped sheets of ice that feed ice to other glacial formations, such as ice sheets, ice fields, and ice islands. They remain frozen year-round, and they serve as sources for glaciers that feed ice into the polar seas in the form of icebergs. Because the polar ice caps are very cold (temperatures in Antarctica have been measured to -126.8°F [-88°C]) and exist for a long time, the caps serve as deep-freezes for geologic information that can be studied by scientists. Ice cores drawn from these regions contain important data for both geologists and environmental scientists about paleoclimatology and give clues about the effects human activities are currently having on the world.

Polar ice caps also serve as reservoirs for huge amounts of the earth's water. Hydrologists suggest that three-quarters of the world's freshwater is frozen at the North and South Poles. Most of this freshwater ice is in the Southern Hemisphere. The Antarctic ice cap alone contains over 90% of the world's glacial ice, some in huge sheets over 2.5 mi (4 km) deep and averaging 1.5 mi (2.4 km) deep across the continent. It has been estimated that enough water is locked up in Antarctica to raise sea levels around the globe over 240 ft (73 m).