Location of the Arctic.

Artificially coloured topographical map of the Arctic region.

MODIS image of the same region.

The Arctic ( /ˈɑrktɪk/ or /ˈɑrtɪk/) is a polar region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, Norway, United States, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost. The area can be defined as north of the Arctic Circle (66° 33'N), the approximate limit of the midnight sun and the polar night. Alternatively, it can be defined as the region where the average temperature for the warmest month (July) is below 10 °C (50 °F); the northernmost tree line roughly follows the isotherm at the boundary of this region.^[1][2]

Socially and politically, the Arctic region includes the northern territories of the eight Arctic states, although by natural science definitions much of this territory is considered subarctic. The Arctic region is a unique area among Earth's ecosystems. The cultures in the region and the Arctic indigenous peoples have adapted to its cold and extreme conditions. In recent years the extent of the sea ice has declined.^[3][4] Life in the Arctic includes organisms living in the ice,^[5] zooplankton and phytoplankton, fish and marine mammals, birds, land animals, plants and human societies.

Etymology[link]

The word Arctic comes from the Greek ἀρκτικός (arktikos), "near the Bear, arctic, northern"^[6] and that from the word ἄρκτος (arktos), meaning bear.^[7] The name refers either to the constellation Ursa Major, the "Great Bear", which is prominent in the northern portion of the celestial sphere, or to the constellation Ursa Minor, the "Little Bear", which contains Polaris, the Pole Star, also known as the North Star.^[8]

Climate[link]

The Arctic's climate is characterized by cold winters and cool summers. Precipitation mostly comes in the form of snow. The Arctic's annual precipitation is low, with most of the area receiving less than 50 centimetres (20 in). High winds often stir up snow, creating the illusion of continuous snowfall. Average winter temperatures can be as low as −40 °C (−40 °F), and the coldest recorded temperature is approximately −68 °C (−90 °F). Coastal Arctic climates are moderated by oceanic influences, having generally warmer temperatures and heavier snowfalls than the colder and drier interior areas. The Arctic is affected by current global warming, leading to Arctic shrinkage and Arctic methane release.

Due to the poleward migration of the planet's isotherms (about 35 mi (56 km) per decade during the past 30 years as a consequence of global warming), the Arctic region (as defined by tree line and temperature) is currently shrinking.^[9] Perhaps the most spectacular result of Arctic shrinkage is sea ice loss. There is a large variance in predictions of Arctic sea ice loss, with models showing near-complete to complete loss in September from 2040 to some time well beyond 2100. About half of the analyzed models show near-complete to complete sea ice loss in September by the year 2100.^[3]

Biota[link]

Plants[link]

Arctic vegetation is composed of plants such as dwarf shrubs, graminoids, herbs, lichens and mosses, which all grow relatively close to the ground, forming tundra. As one moves northward, the amount of warmth available for plant growth decreases considerably. In the northernmost areas, plants are at their metabolic limits, and small differences in the total amount of summer warmth make large differences in the amount of energy available for maintenance, growth and reproduction. Colder summer temperatures cause the size, abundance, productivity and variety of plants to decrease. Trees cannot grow in the Arctic, but in its warmest parts, shrubs are common and can reach 2 m (6 ft 7 in) in height; sedges, mosses and lichens can form thick layers. In the coldest parts of the Arctic, much of the ground is bare; non-vascular plants such as lichens and mosses predominate, along with a few scattered grasses and forbs (like the arctic poppy).

Animals[link]

Muskox

Herbivores on the tundra include the Arctic hare, lemming, muskox, and caribou. They are preyed on by the Arctic fox and wolf. The polar bear is also a predator, though it prefers to hunt for marine life from the ice. There are also many birds and marine species endemic to the colder regions. Other land animals include wolverines, ermines, and Arctic ground squirrels. Marine mammals include seals, walrus, and several species of cetacean—baleen whales and also narwhals, killer whales and belugas.

Natural resources[link]

The Arctic includes sizable natural resources (oil, gas, minerals, fresh water, fish and if the subarctic is included, forest) to which modern technology and the economic opening up of Russia have given significant new opportunities. The interest of the tourism industry is also on the increase.

The Arctic is one of the last and most extensive continuous wilderness areas in the world, and its significance in preserving biodiversity and genotypes is considerable. The increasing presence of humans fragments vital habitats. The Arctic is particularly susceptible to the abrasion of groundcover and to the disturbance of the rare reproduction places of the animals that are characteristic to the region. The Arctic also holds 1/5 of the Earth's water supply.^{[citation needed]}

Paleo-history[link]

Marine fossils in Canadian Arctic

During the Cretaceous, the Arctic still had seasonal snows, though only a light dusting and not enough to permanently hinder plant growth.^{[citation needed]} Animals such as Chasmosaurus, Hypacrosaurus, Troodon, and Edmontosaurus may have all migrated north to take advantage of the summer growing season, and migrated south to warmer climes when the winter came. A similar situation may also have been found amongst dinosaurs that lived in Antarctic regions, such as Muttaburrasaurus of Australia.

Indigenous population[link]

The earliest inhabitants of North America's central and eastern Arctic are referred to as the Arctic small tool tradition (AST) and existed c. 2500 BC. AST consisted of several Paleo-Eskimo cultures, including the Independence cultures and Pre-Dorset culture.^[10][11] The Dorset culture (Inuktitut: Tuniit or Tunit) refers to the next inhabitants of central and eastern Arctic. The Dorset culture evolved because of technological and economic changes during the period of 1050–550 BC. With the exception of the Quebec/Labrador peninsula, the Dorset culture vanished around 1500 AD.^[12] Supported by genetic testing, evidence shows that Dorset culture, known as the Sadlermiut, survived in Aivilik, Southampton and Coats Islands, until the beginning of the 20th century.^[13]

Dorset/Thule culture transition dates around the 9th–10th centuries. Scientists theorize that there may have been cross-contact of the two cultures with sharing of technology, such as fashioning harpoon heads, or the Thule may have found Dorset remnants and adapted their ways with the predecessor culture.^[14] Others believe the Thule displaced the Dorset. By 1300, the Inuit, present-day Arctic inhabitants and descendants of Thule culture, had settled in west Greenland, and moved into east Greenland over the following century. Over time, the Inuit have migrated throughout the Arctic regions of Canada, Greenland, Russia and the United States.^[15]

Other Circumpolar North indigenous peoples include the Chukchi, Evenks, Inupiat, Khanty, Koryaks, Nenets, Sami, Yukaghir, and Yupik, who still refer to themselves as Eskimo which means raw meat eaters.

International cooperation and politics[link]

Polar bears on the sea ice of the Arctic Ocean, near the North Pole. USS Honolulu pictured.

The eight Arctic nations (USA, Canada, Denmark (Greenland & The Faroe Islands), Iceland, Norway, Sweden, Finland and Russia) are all members of the Arctic Council, as are organizations representing six indigenous populations. The Council operates on consensus basis, mostly dealing with environmental treaties and not addressing boundary or resource disputes.

Though Arctic policy priorities differ, every Arctic nation is concerned about sovereignty/defense, resource development, shipping routes, and environmental protection. Much work remains on regulatory agreements regarding shipping, tourism, and resource development in Arctic waters.

Research in the Arctic has long been a collaborative international effort, evidenced perhaps most notably by the International Polar Year. The International Arctic Science Committee, hundreds of scientists and specialists of the Arctic Council, and the Barents Euro-Arctic Council are more examples of collaborative international Arctic research.

Territorial claims[link]

No country owns the geographic North Pole or the region of the Arctic Ocean surrounding it. The surrounding Arctic states that border the Arctic Ocean — Russia, Norway, the United States, Canada, Iceland, and Denmark (via Greenland)—are limited to a 200 nautical miles (370 km; 230 mi) economic zone around their coasts.

Upon ratification of the United Nations Convention on the Law of the Sea, a country has ten years to make claims to extend its 200 nautical mile zone.^[16] Due to this, Norway (which ratified the convention in 1996),^[17] Russia (ratified in 1997),^[17] Canada (ratified in 2003)^[17] and Denmark (ratified in 2004)^[17] launched projects to establish claims that certain Arctic sectors should belong to their territories.

On August 2, 2007, two Russian bathyscaphes, MIR-1 and MIR-2, for the first time in history descended to the Arctic seabed beneath the North Pole and placed there a Russian flag made of rust-proof titanium alloy. The mission was a scientific expedition, but the flag-placing raised concerns of a race for control of the Arctic's vast petroleum resources.^[18] (See Arktika 2007.)

Foreign ministers and other officials representing Canada, Denmark, Norway, Russia, and the United States met in Ilulissat, Greenland on May 28, 2008 at the Arctic Ocean Conference and announced the Ilulissat Declaration,^[19][20] blocking any "new comprehensive international legal regime to govern the Arctic Ocean," and pledging "the orderly settlement of any possible overlapping claims."^[21]

Exploration[link]

Since 1937, the whole Arctic region has been extensively explored by Soviet and Russian manned drifting ice stations. Between 1937 and 1991, 88 polar crews established and occupied scientific settlements on the drift ice and were carried thousands of kilometers by the ice flow.^[22]

Pollution[link]

Long-range pollution pathways to the Arctic

The Arctic is comparatively clean, although there are certain ecologically difficult localized pollution problems that present a serious threat to people’s health living around these pollution sources. Due to the prevailing worldwide sea and air currents, the Arctic area is the fallout region for long-range transport pollutants, and in some places the concentrations exceed the levels of densely populated urban areas. An example of this is the phenomenon of Arctic haze, which is commonly blamed on long-range pollutants. Another example is with the bioaccumulation of PCB's (polychlorinated biphenyls) in Arctic wildlife and people.

Climate change[link]

Arctic sea ice coverage as of 2007 compared to 2005 and also compared to 1979–2000 average

The development of Arctic sea ice volume as estimated by measurement corrected numerical simulation shows probability of total sea ice loss in summer for the near future.^[23]

The Arctic is especially vulnerable to the effects of global warming, as has become apparent in the melting sea ice in recent years. Climate models predict much greater warming in the Arctic than the global average,^[24] resulting in significant international attention to the region. In particular, there are concerns that Arctic shrinkage, a consequence of melting glaciers and other ice in Greenland, could soon contribute to a substantial rise in sea levels worldwide.^[25] Climate models give a range of predictions of Arctic sea ice loss, showing near-complete to complete loss in September anywhere from 2040 to some time well beyond 2100. About half of the analyzed models show near-complete to complete sea ice loss in September by the year 2100.^[3] More recently, the Catlin Arctic Survey concluded that summer ice loss would occur around 2029.^[26]

In September 2008, the extent of the summer Arctic ice cap was at a near-record low, only 9.01 percent greater than the record low in 2007, and 33.6 percent below the average extent of sea ice from 1979 to 2000.^[4] According to the University of Bremen, in September 2011 the Arctic ice cap was smaller than ever before recorded since the satellite measurements started in the 1970s.^[27][28] Arctic ice is declining in area and thinning. Arctic temperatures have risen more than twice as fast as the global average over the past half century. The speed of change has shocked scientists. If current trends continue, a largely ice-free Arctic in the summer is likely within 30 years – up to 40 years earlier than was anticipated by the IPCC last report.^[29]

As the volume of sea ice until recently could not be measured by remote sensing as easy as its extent, numerical models have been made to estimate the ice thickness field between known points, which then is summed up to yield ice volume. The resulting volume over time – plot reveals a much stronger loss of ice than ice extent studies suggest.^[23]

The current Arctic shrinkage is leading to fears of Arctic methane release.^[30] Release of methane stored in permafrost could cause abrupt and severe global warming,^[31] as methane is a potent greenhouse gas. On millennial time-scales, decomposition of methane hydrates in the Arctic seabed could also amplify global warming.^{[citation needed]} Previous methane release events have been linked to the great dying, a mass extinction event at the boundary of the Permian and Triassic, and the Paleocene–Eocene Thermal Maximum, in which temperatures abruptly increased.

Apart from concerns regarding the detrimental effects of warming in the Arctic, some potential opportunities have gained attention as well. The melting of the ice is making the Northwest Passage, the shipping routes through the northernmost latitudes, more navigable, raising the possibility that the Arctic region will become a prime trade route.^[32] In addition, it is believed that the Arctic seabed may contain substantial oil fields which may become accessible if the ice covering them melts.^[33] These factors have led to recent international debates as to which nations can claim sovereignty or ownership over the waters of the Arctic.^{[34][35][36][37]}

The National Oceanic and Atmospheric Administration's Arctic Report Card^[38] presents annually updated, peer-reviewed information on recent observations of environmental conditions in the Arctic relative to historical records.

Eidsfjord in Vesterålen, Norway, situated 250 km (160 mi) inside the Arctic Circle, but the comparatively temperate Norwegian sea gives a mean annual temperature of 4 °C (39 °F) and a 3 month summer above 10°C^[39]

Arctic waters[link]

Arctic lands[link]

See also[link]

	Arctic portal
	Antarctica portal
	Geography portal

References[link]

Further reading[link]

• Sperry, Armstrong (1957). All About the Arctic and Antarctic. Random House. LCCN 57-7518. 
• "Global Security, Climate Change, and the Arctic" – 24-page special journal issue (fall 2009), Swords and Ploughshares, Program in Arms Control, Disarmament, and International Security (ACDIS), University of Illinois
• The Battle for the Next Energy Frontier: The Russian Polar Expedition and the Future of Arctic Hydrocarbons, by Shamil Midkhatovich Yenikeyeff and Timothy Fenton Krysiek, Oxford Energy Comment, Oxford Institute for Energy Studies, August 2007
• GLOBIO Human Impact maps Report on human impacts on the Arctic
• Krupnik, Igor, Michael A. Lang, and Scott E. Miller, eds. Smithsonian at the Poles: Contributions to International Polar Year Science. Washington, D.C.: Smithsonian Institution Scholarly Press, 2009.

External links[link]

Find more about Arctic on Wikipedia's sister projects:
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	Learning resources from Wikiversity
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• Arctic Report Card
• International Arctic Research Center
• Arctic Theme Page Comprehensive Arctic Resource from NOAA.
• Arctic time series: The Unaami Data collection Viewable interdisciplinary, diverse collection of Arctic variables from different geographic regions and data types.
• WWF International Arctic Programme Arctic environment and conservation information
• Bering Sea Climate and Ecosystem Current state of the Bering Sea Climate and Ecosystem. Comprehensive resource on the Bering Sea with viewable oceanographic, atmospheric, climatic, biological and fisheries data with ecosystem relevance, recent trends, essays on key Bering Sea issues, maps, photos, animals and more. From NOAA.

Maps

• Arctic Environmental Atlas Circum-Arctic interactive map, with multiple layers of information
• Interactive Satellite Map with daily update (true color/infrared)

Media

• "Global Security, Climate Change, and the Arctic" – streaming video of November 2009 symposium at the University of Illinois
• Implications of an Ice-Free Arctic for Global Security – November 2009 radio interview with Professor Klaus Dodds (Royal Holloway, University of London)
• The Canadian Museum of Civilization – The Story of the Canadian Arctic Expedition of 1913–1918
• UNEP/GRID-Arendal Maps and Graphics library Information resources from the UN Environment programme
• Arctic Institute of North America Digital Library Over 8000 photographs dating from the late 19th century through the 20th century.
• euroarctic.com News service from the Barents region provided by Norwegian Broadcasting Corp (NRK), Swedish Radio (SR) and STBC Murman.
• arcticfocus.com Independent News service covering Arctic region with daily updates on environment, Arctic disputes and business
• Vital Arctic Graphics Overview and case studies of the Arctic environment and the Arctic Indigenous Peoples.
• Arctic and Taiga Canadian Atlas
• Scientific Facts on Arctic Climate Change
• PolarTREC PolarTREC-Teachers and Researchers Exploring and Collaborating
• Arctic Change: Information on the present state of Arctic ecosystems and climate, presented in historical context (from NOAA, updated regularly)
• Monthly Sea Ice Outlook
• UN Environment Programme Key Polar Centre at UNEP/GRID-Arendal
• Arctic Geobotanical Atlas, University of Alaska Fairbanks
• Polar Discovery
• Arctic Transform Transatlantic Policy Options for Supporting Adaptation in the Marine Arctic
• ArticStat Circumpolar Database

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