View source for Earth:Polar regions of Earth

{{Short description|Regions around the Earth's geographical poles}}
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[[File:Pulse of Snow and Sea Ice.ogv|thumb|Visualization of the ice and snow covering Earth's northern and southern polar regions]]
[[File:Frozenground.gif|thumb|Northern Hemisphere [[Earth:Permafrost|permafrost]] (permanently frozen ground) in purple]]

The '''polar regions''', also called the '''frigid zones''' or '''polar zones''', of [[Astronomy:Earth|Earth]] are Earth's [[Earth:Polar ice cap|polar ice cap]]s, the [[Earth:Region|region]]s of the planet that surround its [[Earth:Geographical pole|geographical pole]]s (the [[Earth:North Pole|North]] and [[Earth:South Pole|South Pole]]s), lying within the polar circles. These '''high latitudes''' are dominated by floating [[Earth:Arctic ice pack|sea ice]] covering much of the [[Earth:Arctic Ocean|Arctic Ocean]] in the north, and by the [[Earth:Antarctic ice sheet|Antarctic ice sheet]] on the continent of [[Earth:Antarctica|Antarctica]] and the [[Earth:Southern Ocean|Southern Ocean]] in the south.

==Definitions==
The Arctic has various definitions, including the region north of the Arctic Circle (currently Epoch 2010 at 66°33'44" N), or just the region north of 60° north latitude, or the region from the North Pole south to the [[Earth:Tree line|timberline]]. The Antarctic is usually defined simply as south of 60° south latitude, or the continent of Antarctica. The 1959 Antarctic Treaty uses the former definition.

The two polar regions are distinguished from the other two climatic and biometric belts of Earth, a tropics belt near the equator, and two middle latitude regions located between the tropics and ''polar regions''.

==Climate==
{{main|Earth:Polar climate}}
Polar regions receive less intense [[Physics:Solar radiation|solar radiation]] than the other parts of Earth because the Sun's energy arrives at an oblique angle, spreading over a larger area, being less concentrated, and also travels a longer distance through the Earth's atmosphere in which it may be absorbed, scattered or reflected, which is the same thing that causes winters to be colder than the rest of the year except in tropical regions.

The [[Astronomy:Axial tilt|axial tilt]] of the Earth has the most effect on climate of the polar regions due to its latitude. However, since the polar regions are the farthest from the [[Astronomy:Equator|equator]], they receive the weakest solar radiation and are therefore generally frigid year round due to the earth's axial tilt of 23.5° not being enough to create a high maximum midday declination to sufficiently compensate the Sun's rays for the high latitude even in summer, except for relatively brief periods in peripheral areas near the polar circles. The large amount of ice and snow also reflects and weakens of what weak sunlight the polar regions receive further, contributing to the cold. Polar regions are characterized by extremely cold temperatures, heavy glaciation wherever there is sufficient precipitation to form permanent [[Earth:Ice|ice]], short and still cold summers, and extreme variations in daylight hours, with [[Astronomy:Midnight sun|twenty-four hours of daylight]] in summer, and [[Earth:Polar night|complete darkness]] at mid-winter.

==Circumpolar Arctic region==
[[File:Polar Bear 2004-11-15.jpg|thumb|North polar region polar bears]]
There are many settlements in Earth's north polar region. Countries with claims to Arctic regions are: the {{wipe|United States}} ([[Earth:Alaska|Alaska]]), {{wipe|Canada}} ([[Earth:Yukon|Yukon]], the [[Earth:Northwest Territories|Northwest Territories]] and [[Earth:Nunavut|Nunavut]]), {{wipe|Denmark}} ([[Place:Greenland|Greenland]]), {{wipe|Norway}}, {{wipe|Finland}}, Sweden, Iceland, and {{wipe|Russia}}. Arctic circumpolar populations, though small, often share more in common with each other than with other populations within their national boundaries. As such, the northern polar region is diverse in human settlements and cultures.

==Antarctica and the Southern sea==
[[File:Pygoscelis papua.jpg|thumb|upright|South polar region penguin]]
The southern polar region has no permanent human habitation as of now.<ref>{{cite web|url=https://www.bbc.com/news/magazine-27910375|title=Why do so many nations want a piece of Antarctica?|publisher=BBC|language=en|author=Matthew Teller|date=20 June 2014|access-date=22 March 2019}}</ref> [[Engineering:McMurdo Station|McMurdo Station]] is the largest research station in [[Earth:Antarctica|Antarctica]], run by the United States. Other notable stations include Palmer Station and Amundsen–Scott South Pole Station (United States), Esperanza Base and Marambio Base ({{wipe|Argentina}}), Scott Base ([[Earth:New Zealand|New Zealand]]), and Vostok Station (Russia).

While there are no indigenous human cultures, there is a complex ecosystem, especially along Antarctica's [[Earth:Coast|coast]]al zones. Coastal [[Earth:Upwelling|upwelling]] provides abundant nutrients which feeds [[Biology:Krill|krill]], a type of marine [[Biology:Crustacea|Crustacea]], which in turn feeds a complex of living creatures from penguins to blue whales.

== See also ==
* [[Physics:Cryosphere|Cryosphere]]
* [[Earth:Polar climate|Polar climate]]

== References ==
{{Reflist}}

==Further reading==
* Victor, Paul-Émile. ''Man and the Conquest of the Poles'', trans. by Scott Sullivan. New York: Simon & Schuster, 1963.{{ISBN?}}

== External links ==
* {{curlie|Regional/Polar_Regions/|Polar regions}}
* [http://www.barrameda.com.ar/ecology/the-polar-regions.htm The Polar Regions]
* [http://www.polarfoundation.org/ International Polar Foundation]
* [https://web.archive.org/web/20061230092300/http://maps.grida.no/arctic/ Arctic Environmental Atlas (UNDP)]
* [https://web.archive.org/web/20100110214619/http://www.windows.ucar.edu/polar.html Earth's Polar Regions on Windows to the Universe]
* [https://web.archive.org/web/20160122063205/http://www.mnh.si.edu/arctic/index.html Arctic Studies Center, Smithsonian Institution]
* [http://www.spri.cam.ac.uk/ Scott Polar Research Institute, University of Cambridge]
* [https://web.archive.org/web/20090204083036/http://www.panda.org/news_facts/education/middle_school/habitats/polar_regions/index.cfm WWF:The Polar Regions]
* [https://www.theguardian.com/environment/gallery/2007/jun/05/photography?picture=329977040 World Environment Day 2007 "Melting Ice" image gallery at The Guardian]
* [http://polardiscovery.whoi.edu/ Polar Discovery]

{{Regions of the world}}

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[[Category:Arctic Ocean]]

{{Sourceattribution|Polar regions of Earth}}