Arctic Circle (Arctic Circle)

The Arctic Circle is one of the two polar circles and the most northerly of the five major circles of latitudeas shown on maps of Earth. It marks the northernmost point at which the center of the noon sun is just visible on the December solstice and the southernmost point at which the center of the midnight sun is just visible on the June solstice. The region north of this circle is known as the Arctic, and the zone just to the south is called the Northern Temperate Zone.

As seen from the Arctic, the Sun is above the horizon for 24 continuous hours at least once per year (and therefore visible at midnight) and below the horizon for 24 continuous hours at least once per year (and therefore not visible at noon). This is also true in the Antarctic region, south of the equivalent Antarctic Circle.

The position of the Arctic Circle is not fixed and currently runs 66°33′48.6″ north of the Equator. Its latitude depends on the Earth's axial tilt, which fluctuates within a margin of more than 2° over a 41,000-year period, owing to tidal forces resulting from the orbit of the Moon. Consequently, the Arctic Circle is currently drifting northwards (shrinking) at a speed of about 15 m (49 ft) per year.

The Arctic Circle is a region of tremendous economic and geo-strategic importance. One-third of the world's maritime shipping passes through it, carrying over US$3 trillion in trade each year. Huge oil and natural gas reserves are believed to lie beneath its seabed. It also contain lucrative fisheries, which are crucial for the food security of millions in Northern Europe.