e-Learning portal for Arctic Biology

The Arctic and the Arctic Circle

The Arctic is named after the northern star constellation “Arktos”—Greek for “bear”. It consists of the Arctic Ocean and surrounding landmasses. Depending on the definition of the Arctic, between 14.5 million and 30 million km2 of the Earth’s landmass, (1/6th) belonging to the Arctic. 

The Arctic has been inhabited by humans for close to 20,000 years. Currently, eight countries have land within the Arctic: Greenland/Denmark, Iceland, Norway, Sweden, Finland, Russia, the USA and Canada.

Definition of the Arctic

The simplest definition of the Arctic refers to the area north of the Arctic Circle:

  • The approximate southern limit of the midnight sun and the polar night. This means the sun doesn’t set on the summer solstice and does not come above the horizon on the winter solstice. 
  • These limits are not entirely fixed and fluctuate slightly on a geological time scale.

Other definitions are based on specific environmental or ecological characteristics:

  • 10°C summer isotherm, where the average temperature of the warmest month (July) is below 10°C
  • Or 4°C summer isotherm for the high Arctic
  • The northernmost tree line, which roughly follows the 10°C isotherm

A map of the Arctic showing different delineations and more can be found here or here. A bathymetric map can be found here.

The northern polar region showing the different deliniations of the Arctic, areas with permafrost, minimum and maximum sea ice cover and the 8 Arctic states (click to enlarge).

Source:  CAFF’s Flora and Fauna: Status and Conservation, 2001.