Polar region

From Wikipedia, the free encyclopedia

Earth's polar regions are the areas of the globe surrounding the poles. The Arctic has numerous definitions such as north of the Arctic circle (66-33N) or north of 60 degrees north latitude or by vegetation or temperature regimes. The Antarctic is usually defined as south of 60 degrees south latitude, and almost never limited to areas just south of the Antarctic Circle. The all-encompassing 1959 Antarctic Treaty uses 60 degrees, a measure now generally accepted.

Polar regions are characterised by the polar climate, extremely cold temperatures, heavy glaciation, and extreme variations in daylight hours, with 24 hour daylight in summer (the midnight sun), and permanent darkness at mid-winter.

The North Pole and South Pole being the centres, these regions are dominated by the polar ice caps, resting respectively on ocean and the continent of Antarctica. Both of the Earth's ice caps are currently shrinking, possibly as a result of anthropogenic global warming.

There are many settlements in Earth's north polar regions, but none except for scientific bases in the south polar regions, which are colder than the northern polar regions.

Other planets and natural satellites in the solar system have interesting quirks about their polar regions. Earth's Moon is thought to contain substantial deposits of ice in deep craters in its polar regions, which never see direct sunlight. Mars, like Earth, has polar caps, but unlike Earth's icy caps they consist mostly of carbon dioxide. On Uranus, meanwhile, the extreme tilt of the planet's axis leads to the unique situation during the Uranian year of first one pole and then the other pointing almost directly at the Sun.

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International Polar Foundation

Regions of the world

Image:LocationAfrica.png	Africa	Central • Eastern • Northern • Southern • Western
Image:LocationAmericas.png	Americas	Caribbean • Central • Latin • North • Northern • South
	Asia	Central • Eastern • Northern • Southern • Southeastern • Western
Image:LocationEurope.png	Europe	Central • Eastern • Northern • Southern • Western
	Oceania	Australasia • Melanesia • Micronesia • Polynesia

Image:LocationPolarRegions.png	Polar	Arctic • Antarctic
Image:LocationOceans.png	Oceans	Pacific • Atlantic • Indian • Southern • Arctic