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 landmasses (1/6th) belong to the Arctic. 

The Arctic has been inhabited by humans for close to 20,000 years and today 8 contries have landareas within the Arctic: Greenland/Danmark, Island, Norway, Sweden, Finnland, Russia, 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 at least the summer solstice and does not come above the horizon at least on winter solstice. 
  • It is not entirely fixed and fluctuates slightly on geological time scale.

Other perhaps more accurate 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 maps of the Arctic showing different deliniations and more can be found here or here. A bathymetric map can be found here.

The northern polar region with lines showing the different deliniations of the Arctic, areas with permafrost, minimum and maximum sea ice cover and the 8 Arctic states. Click on the image to enarge.

Source: The figure is taken from the CAFF’s Flora and Fauna: Status and Conservation, 2001.