Climate of the Arctic and Global warming in the Arctic

The word Arctic comes from the Greek word ἀρκτικός (arktikos), "near the Bear, northern"[4] and that from the word ἄρκτος (arktos), meaning bear.[5] 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.[6]

There are a number of definitions of what area is contained within the Arctic. The area can be defined as north of the Arctic Circle (66° 33'N), the approximate southern limit of the midnight sun and the polar night. Another definition of the Arctic, which is popular with ecologists, is the region in the Northern Hemisphere 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.[7][8]

Climate
Main articles: Climate of the Arctic and Global warming in the Arctic
The Arctic is characterized by cold winters and cool summers. Its precipitation mostly comes in the form of snow and is low, with most of the area receiving less than 50 cm (20 in). High winds often stir up snow, creating the illusion of continuous snowfall. Average winter temperatures can go 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 sea ice shrinkage, diminished ice in the Greenland ice sheet, and Arctic methane release as the permafrost thaws.[9] The melting of Greenland's ice sheet is linked to polar amplification.[10]

Due to the poleward migration of the planet's isotherms (about 56 km (35 mi) 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.[11] Perhaps the most alarming result of this is Arctic sea ice shrinkage. There is a large variance in predictions of Arctic sea ice loss, with models showing near-complete to complete loss in September from 2035 to some time around 2067.[12][13]

Flora and fauna
Arctic life is characterized by adaptation to short growing seasons with long periods of sunlight, and to cold, dark, snow-covered winter conditions.

Plants

Arctic poppy in bloom within the Qausuittuq National Park on Bathurst Island
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. An example of a dwarf shrub is the bearberry. 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
See also: List of Arctic cetaceans
See also: the categories Fauna of the Arctic and Mammals of the Arctic

Muskox

A snowy owl
Herbivores on the tundra include the Arctic hare, lemming, muskox, and caribou. They are preyed on by the snowy owl, Arctic fox, Grizzly bear, and Arctic 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 terrestrial animals include wolverines, moose, Dall sheep, ermines, and Arctic ground squirrels. Marine mammals include seals, walrus, and several species of cetacean—baleen whales and also narwhals, killer whales, and belugas. An excellent and famous example of a ring species exists and has been described around the Arctic Circle in the form of the Larus gulls.

Natural resources
See also: Natural resources of the Arctic and Petroleum exploration in the Arctic
The Arctic includes copious 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 contains some 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 breeding grounds of the animals that are characteristic to the region. The Arctic also holds 1/5 of the Earth's water supply.[14]

Paleontology

Marine fossils in Canadian Arctic
During the Cretaceous time period, the Arctic still had seasonal snows, though only a light dusting and not enough to permanently hinder plant growth. Animals such as the 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 winter came. A similar situation may also have been found amongst dinosaurs that lived in Antarctic regions, such as the Muttaburrasaurus of Australia.

However, others claim that dinosaurs lived year-round at very high latitudes, such as near the Colville River, which is now at about 70° N but at the time (70 million years ago) was 10° further north.[15]

Indigenous population
Main article: Circumpolar peoples
Further information: Indigenous peoples of Siberia and Inuit Circumpolar Council

Circumpolar coastal human population distribution c. 2009 (includes indigenous and non-indigenous).
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 BCE. AST consisted of several Paleo-Eskimo cultures, including the Independence cultures and Pre-Dorset culture.[16][17] 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 BCE. With the exception of the Quebec/Labrador peninsula, the Dorset culture vanished around 1500 CE.[18] Supported by genetic testing, evidence shows that descendants of the Dorset culture, known as the Sadlermiut, survived in Aivilik, Southampton and Coats Islands, until the beginning of the 20th century.[19]

The Dorset/Thule culture transition dates around the 9th–10th centuries CE. 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.[20] Others believe the Thule displaced the Dorset.

By 1300 CE, 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 (Inughuit, Kalaallit and Tunumiit are modern Greenlandic Inuit groups descended from Thule). Over time, the Inuit have migrated throughout the Arctic regions of Eastern Russia, the United States, Canada, and Greenland.[21]

Other Circumpolar North indigenous peoples include the Chukchi, Evenks, Iñupiat, Khanty, Koryaks, Nenets, Sami, Yukaghir, Gwich'in, and Yupik.

International cooperation and politics
Main article: Arctic cooperation and politics

Polar bears on the sea ice of the Arctic Ocean, near the North Pole. USS Honolulu pictured.
The eight Arctic nations (Canada, Kingdom of Denmark [Greenland & The Faroe Islands], Finland, Iceland, Norway, Sweden, Russia, and USA) 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.[22] Much work remains on regulatory agreements regarding shipping, tourism, and resource development in Arctic waters.[23]

Research in the Arctic has long been a collaborative international effort, evidenced 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
Main article: Territorial claims in the Arctic
No country owns the geographic North Pole or the region of the Arctic Ocean surrounding it. The surrounding six Arctic states that border the Arctic Ocean—Canada, Kingdom of Denmark (with Greenland), Iceland, Norway, Russia, and the United States—are limited to a 200 nautical miles (370 km; 230 mi) exclusive economic zone (EEZ) off their coasts. Two Arctic states (Finland and Sweden) do not have direct access to the Arctic Ocean.

Upon ratification of the United Nations Convention on the Law of the Sea, a country has ten years to make claims to an extended continental shelf beyond its 200 nautical mile zone.[22][24] Due to this, Norway (which ratified the convention in 1996),[25] Russia (ratified in 1997),[25] Canada (ratified in 2003)[25] and the Kingdom of Denmark (ratified in 2004)[25] launched projects to establish claims that certain sectors of the Arctic seabed should belong to their territories.

On 2 August 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 flag-placing during Arktika 2007 generated commentary on and concern for a race for control of the Arctic's vast hydrocarbon resources.[26]

Map of the Arctic region showing the Northeast Passage, the Northern Sea Route within it, and the Northwest Passage.
Foreign ministers and other officials representing Canada, the Kingdom of Denmark, Norway, Russia, and the United States met in Ilulissat, Greenland on 28 May 2008 at the Arctic Ocean Conference and announced the Ilulissat Declaration,[27][28] blocking any "new comprehensive international legal regime to govern the Arctic Ocean," and pledging "the orderly settlement of any possible overlapping claims."[22][29]

As of 2012, the Kingdom of Denmark is claiming the continental shelf based on the Lomonosov Ridge between Greenland and over the North Pole to the northern limit of the Russian EEZ.[30]

The Russian Federation is also claiming a large swath of seabed along the Lomonosov Ridge but, unlike Denmark, confined its claim to its side of the Arctic. In August 2015, Russia made a supplementary submission for the expansion of the external borders of its continental shelf in the Arctic Ocean, asserting that the eastern part of the Lomonosov Ridge and the Mendeleyev Ridge are an extension of the Eurasian continent. In August 2016, the UN Commission on the Limits of the Continental Shelf began to consider Russia's submission.[31]

Canada claims the Northwest Passage as part of its internal waters belonging to Canada, while the United States and most maritime nat