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.