The Arctic Circle is the parallel of latitude that runs 66° 33' 39," or roughly 66.5°, north of the Equator. Approximately 15,000 kilometers (9,300 miles) to the south is the Antarctic Circle, of equal diameter to and parallel to the Arctic Circle as well as equally distant from the Equator. Together with the Equator and the tropics of Cancer and Capricorn, these five unseen circular lines comprise the major circles of latitude that mark maps of the Earth. All five are determined by the Earth's rotation on its axis and the Earth's tilt toward and away from the Sun in its orbit. The circle, though invisible and, in fact, moving, is a product of the same phenomenon that provides the world with four seasons and this largely austere part of the globe with an odd formula of light and darkness shared only by its polar opposite.
The Geometry of the Circle
The Arctic Circle marks the southern extremity of the polar day of the summer solstice in June and the polar night of the winter solstice in December. Within the whole area of the Arctic Circle, the Sun is above the horizon for at least 24 continuous hours once per year, in conjunction with the Arctic's summer solstice, which is often referred to as the "midnight sun." Likewise, in conjunction with the Arctic's winter solstice, the Arctic sun will be below the horizon in the entire area for at least 24 continuous hours, which could just as easily be called the "noontime night." The darkness is often alleviated, though, by the awesome beauty of the Aurora Borealis, or "Northern Lights," which result from the interplay of the Earth's magnetic field and the solar wind. Points within the circle experience longer periods of continuous light and darkness depending on their proximity to the North Pole, where six months of sunlight alternate with a half-year of darkness.
(In fact, because of refraction and because the sun appears as a disk and not a point, part of the midnight sun may be seen at the night of the summer solstice up to about 90 km (56 miles) south of the Arctic Circle; similarly, at the day of the winter solstice part of the sun may be seen up to about 90 km north of the circle. This is true at sea level; these limits increase with elevation above sea level, but in mountainous regions there is often no direct view of the horizon.)
Because of a slow wobble that the Earth has in its rotation over a period of more than 40,000 years, the Arctic Circle also moves slowly about, to the point that it is problematic to say exactly where it lies even one day to the next. Over a period of nearly 20 years, the Earth's tilt oscillates about 280 meters (924 feet), which causes the circle at present to be moving north at the rate of about 14 meters (46 feet) per year.
The Circle's Name
The Arctic Ocean lies wholly within the Arctic Circle. The ocean, the circle, and the region take their names from the Greek word arctus, meaning "bear," a reference to the Big and Little Bear constellations that can always be seen overhead on clear nights in the polar region.
Everything north of the Arctic Circle is properly known as the Arctic while the zone just to the south of the circle is the Northern Temperate Zone. The North Pole lies about 2,600 kilometers (1,600 miles) from the Arctic Circle. Because of the moderating influence of open water-even warm water escaping from under polar pack ice- the North Pole is often less cold than points on the circle.
Countries on the Circle
There are seven countries that have significant territory within the Arctic Circle. They are, in order from the International Date Line heading east:
- United States (Alaska)
The nation of Iceland barely grazes the Arctic Circle, with less than one km² of its territory lying north of it. The line crosses or passes south of just a few tiny islets.
Greenland is the only one of these countries with most of its area within the circle, though the vast majority of its population resides south of it.
Circumpolar Population, Transport Lines, and Economy
In contrast to the area south of the Antarctic Circle, where there are virtually no permanent residents, the population of the total area north of the Arctic Circle is in the vicinity of two million. The majority (more than 60 percent) are in Russia, followed in order by Norway and Finland. The Arctic population of North America, including Greenland, comprises less than three percent of all people living within the circle. Murmansk in northwestern Russia is the circumpolar region's largest city.
The ethnic links among the indigenous people of the Arctic are not at all certain though they share some elements of their daily lifestyle, such as clothing, shelter, and weaponry. Linguistic connections haven't been found, and the different communities have historically been isolated from one another. The Inuit people (once called Eskimos) of Greenland, Canada, and Alaska have tenuous but slowly growing links with the native people of northern Siberia, such as the Nenet and Yakut.
The three Nordic nations have each built a railroad line extending north of the circle but connecting with their national capitals well to the south. In Norway's and Finland's case, the railways stretch a relatively short distance, but in Sweden's the track nearly reaches the nation's northern limits. In Russia there are two lines, one to Murmansk and the other farther east, yet west of the Ural Mountains. No rail lines have been built into the Arctic in North America. A proposed rail tunnel under the Bering Strait to Siberia would lie just south of the Arctic Circle.
The Nordic countries all have highway systems extending well into their Arctic territory, as does Russia in the Murmansk region. Canada's Dempster Highway, also referred to as Yukon Highway 5 and Northwest Territories Highway 8, is a highway that connects the Klondike Highway in Yukon, Canada to Inuvik, Northwest Territories on the Mackenzie River delta. During the winter months, the highway extends to Tuktoyaktuk, on the northern coast of Canada, using frozen portions of the Mackenzie River delta as an ice road also known as the Tuktoyaktuk Winter Road. The highway crosses the Peel River and the Mackenzie Rivers using a combination of seasonal ferry service and ice bridges. Canada has no such links into the Arctic sections of its Nunavut territories. The James Dalton Highway in Alaska reaches from Fairbanks, Alaska to the Arctic Ocean at the town of Deadhorse, Alaska along the North Slope. The town consists of facilities for the workers and companies that operate at the nearby Prudhoe Bay oil fields.
Though there is a growing interest in travel north of the Arctic Circle focusing particularly on the area's relatively non-endangered wildlife and endangered wildlife such as polar bears, tourism remains on a fairly low scale. Quick visits by adventurers to the North Pole are somewhat popular among those who seek to be able to claim they have been there.
Farming is difficult in the Arctic since much of the ground is tundra, though there are certain crops in prepared soil, such as cabbage, that grow large quickly in the continuous light of the midnight sun. Fishing and the land bound industries related to it are the dominant source of livelihood, along with hunting. The herding and care of reindeer are an enduring activity in the Lapland (or Sami) sections of Finland, Sweden, and Norway.
There are major, but not generally well known, rivers flowing north past the Arctic Circle into the Arctic Ocean. The Mackenzie River runs through the Northwest Territories and empties into the ocean a few hundred kilometers east of Alaska's northeast corner. The Ob, Yenisey, and Lena rivers of Siberia drain immense areas of northern Asia even as far south as Kazakhstan and Mongolia and meet the ocean in extensive estuaries and deltas that are frozen in winter.
Many islands and small archipelagoes are strewn about the Arctic. Besides Greenland, Earth's largest island, there are several others that are also among the world's biggest. They have such names as Canada's Baffin, Victoria, and Ellesmere islands; Norway's Spitsbergen; and Russia's Novaya Zemlya and Wrangel Island.
All links retrieved April 12, 2016.
- What is the Arctic? National Snow & Ice Data Center
- The Arctic WorldAtlas