thumb|300px|right|The red line indicates the 10°C isotherm in July, sometimes used to define the Arctic region borderthumb|300px|right|Artificially coloured topographical map of the Arctic regionThe
Arctic ( or ) is the
region around the
Earth's
North Pole, opposite the
Antarctic region around the
South Pole. The Arctic includes the
Arctic Ocean (which overlies the North Pole) and parts of
Canada,
Greenland (a territory of
Denmark),
Russia, the
United States (
Alaska),
Iceland,
Norway,
Sweden and
Finland.
The word Arctic comes from the
Greek αρκτικός (
arktikos), "near the Bear, arctic, northern" and that from the word
άρκτος (
arktos), which means
bear. 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.
The Arctic region can be defined as the area north of the
Arctic Circle (66° 33’N), which is 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 ; the northernmost
tree line roughly follows the
isotherm at the boundary of this region. 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 consists of a vast,
ice-covered ocean (which is sometimes considered to be a northern arm of the
Atlantic Ocean) surrounded by treeless
permafrost. In recent years the extent of the sea ice has declined. Life in the Arctic includes organisms living in the ice,
zooplankton and
phytoplankton, fish and marine mammals, birds, land animals, plants, and human societies.
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.
Due to the poleward migration of the planet's
isotherms (about 35 miles 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. 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.
Nature
Climate
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 . High winds often stir up snow, creating the illusion of continuous snowfall. Average winter temperatures can be as low as , and the coldest recorded temperature is approximately . 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.
Plants
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 in height; sedges, mosses and lichens can form thick layers. In the coldest parts of the Arctic, much of the ground is bare;
nonvascular plants such as
lichens and
mosses predominate, along with a few scattered grasses and
forbs (like the Arctic poppy).
Animals
thumb|MuskoxHerbivores 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
The Arctic includes sizable
natural resources (oil, gas, minerals, forest—if the subarctic is included—and fish) 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.
Paleo-history
Marine [[fossils in Canadian Arctic|thumb]]
During the
Cretaceous, the Arctic still had seasonal snows, though only a light dusting and not enough to permanently hinder plant growth. 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
The
Inuit are the descendants of what
anthropologists call the
Thule culture, a nomadic people who emerged from western Alaska around 1000 CE and spread eastwards across the Arctic, displacing the related
Dorset culture (in
Inuktitut, the
Tuniit). Inuit legends speak of the Tuniit as "giants", people who were taller and stronger than the Inuit, but who were easily scared off and retreated from the advancing Inuit. Researchers believe that the Dorset culture lacked dogs, boats and other technologies that gave the expanding Inuit society a large advantage over them. By 1300, the Inuit had settled west Greenland, and finally moved into east Greenland over the following century.
The Tuniit survived in
Aivilik,
Southampton and
Coats Islands, until the beginning of the 20th century. They were known as
Sadlermiut (
Sallirmiut in the modern spelling). Their population had been ravaged by diseases brought by contact with Europeans, and the last of them fell in a flu epidemic caught from a passing whaler in 1902. The area has since been resettled by Inuit. Genetic research suggests that there was little or no intermarriage between the Tuniit and the Inuit over the thousand years of contact in the
Canadian Arctic.
International cooperation and politics
The Arctic region is a focus of international political interest. International Arctic cooperation got underway on a broad scale well over ten years ago. The International Arctic Science Committee (IASC), hundreds of scientists and specialists of the
Arctic Council, the Barents Euro-Arctic Council and its regional cooperation have compiled high quality information on the Arctic.
Territorial claims
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 and
Denmark (via
Greenland)—are limited to a 370 kilometre (200 nautical mile) 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 mile zone. Due to this, Norway (which ratified the convention in 1996),
Russia (ratified in 1997),
Canada (ratified in 2003)
and Denmark (ratified in 2004)
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. (See
2007 Russian North Pole expedition.)
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.
Scientific exploration
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.
Pollution
thumb|right|Long-range pollution pathways to the ArcticThe 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
thumb|250px|right|[[Arctic shrinkage|Arctic sea ice coverage as of 2007 compared to 2005 and also compared to 1979–2000 average]]
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, 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. 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.
More recently, the
Catlin Arctic Survey concluded that summer ice loss would occur around 2029.
In September 2008, the extent of the summer Arctic ice cap was at a near-record low, only 9 percent greater than the record low in 2007, and 33.6 percent below the average extent of sea ice from 1979 to 2000.
[ National Snow and Ice Data Center. Retrieved May 1, 2009.]The current
Arctic shrinkage is leading to fears of
Arctic methane release. Release of
methane stored in
permafrost could cause abrupt and severe
global warming, as
methane is a potent
greenhouse gas. On millennial time-scales, decomposition of
methane hydrates in the Arctic seabed could also amplify global warming. 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. However, it should be noted that these advantages are minor compared to the harm which would result if a
runaway global warming event were to occur. 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. In addition, it is believed that the Arctic seabed may contain substantial
oil fields which may become accessible if the ice covering them melts. These factors have led to recent international debates as to which nations can claim sovereignty or ownership over the waters of the Arctic.
[Shaw, Rob. Victoria Times Colonist. July 9, 2007.]The
National Oceanic and Atmospheric Administration's Arctic Report Card presents annually-updated, peer-reviewed information on recent observations of environmental conditions in the Arctic relative to historical records. In 2008, there continues to be widespread and, in some cases, dramatic evidence of an overall warming of the Arctic system.
Arctic waters
Arctic lands
See also
