The word Arctic comes from the Greek αρκτος, bear, and refers to constellations Ursa Major and Minor, near by the Polar Star. But defining what is meant by the term Arctic is quite complex. Indeed there are several ways to do so but none of them is complete in all respects. We will try explain below the various definitions.

Arctic Circle
A first definition has been conventionally created and define the Arctic the group of lands and seas located north of the Arctic Circle, latitude 66 ° 33 ‘N. Although this option appears to be obvious, however, does not take into account the climatic conditions. In fact at the same latitude the climatic conditions are very different depending on longitude. For example, the Labrador Current brings with it cold water through the Strait of Davis cooling the eastern coast of Canada and the west coast of Greenland while the Gulf Stream warms the North Atlantic to the west coast of Svalbard, often free of ice despite located at a latitude of between 76 ° and 80 ° N.

Arctic Convergence
Another possibility would be to create a parallel with the Antarctic where there is a clear division between the warm subtropical waters and the cold polar waters called Antarctic Convergence. But this phenomenon in the Arctic is much less defined and continuous and it is very difficult to talk about Arctic convergence.

Limit of the Pack
The disadvantage of this method is the seasonal position of the pack that can be very different during the year and also is very difficult to fix the hypothetical position of the sea ice through the continental landmasses.

The lands surrounding the Arctic Ocean offers another definition, the northern limit of trees growth. In the North Atlantic this boundary, thanks to the Gulf Stream, will be located at a latitude far more north than in the North America where trees rarely grow north of 60° parallel. In addition, the conformation of the territory, the characteristics of the soil, altitude are factors that can make small forests grow in isolated areas of tundra.

Isotherm 10° C
Means an imaginary line connecting all points where the main temperature in the hottest month of the year is 10° C. In this case we have a definition closely linked to the timberline. This despite the assumption that is the cold that prevent trees from progressing northward, in Siberia trees grow where winter temperatures are the lowest of the whole northern hemisphere, what stops trees is low summer temperature.

In conclusion any of these definitions is subject to debate and consequently any proposed territory or sea will include areas that in some opinion may be wrong. Actually there are other more specific subdivisions, terms such as “high” or “low” Arctic, subarctic, etc. but essentially they don’t define better the topic.