Polar ice cap

Polar ice cap

A Polar ice cap or polar cap is a high-latitude region of a planet, dwarf planet, or natural satellite that is covered in ice. There are no requirements with regard to size or composition for a body of ice to be termed a polar ice cap, nor any climatic conditions necessary for it to form. The Earth's polar caps are composed of water ice, while Mars's polar ice caps are believed to be composed primarily of water ice with a smaller amount of dry ice (solid carbon dioxide).

Earth's polar ice caps

The Earth's polar caps have changed dramatically over the last 12,000 years. Seasonal variations of the ice caps will take place due to varied solar energy absorption as the planet or moon revolves around the Sun. Additionally, in geologic time scales, the ice caps may grow or shrink due to climate variation.

North Pole

The North Pole of Earth is covered by floating pack ice (sea ice) over the Arctic Ocean. Portions of the ice that do not melt seasonally can get very thick, up to 3–4 meters thick over large areas, with ridges up to 20 meters thick. One-year ice is usually about 1 meter thick. The area covered by sea ice ranges between 9 and 12 million km².

South Pole

The South Pole of Earth is covered by the continent of Antarctica. Due to the Antarctic ice sheet, the South Pole is elevated at an altitude of 2,800 meters above sea level. The highest point of Antarctica, Mount Vinson, is 4,892 meters above sea level.

Mars's polar ice caps

Mars also has polar ice caps. The Mars's polar ice caps were first observed by the Mariner 4 spacecraft in 1965. The northern polar cap has a diameter of about 1,000 kilometers during the northern Mars summer, and contains about 1.6 million cubic kilometers of ice, which, if spread evenly on the cap, would be 2 kilometers thick.

See also

• Climate change
• Global warming
• Ice age
• Sea level rise

References

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