Why the Arctic is Always Cold

An Explanation of the Relationship between Latitude and Temperature

Dec 26, 2008

The Earth's polar regions are perennially cold. The explanation for their climates lies in the Earth's curve decreasing the sun energy those areas receive.

The Earth’s curvature impacts its climate in that it increases the area the sun must cover as latitude increases.

Picture the Northern Hemisphere of the Earth sitting on top of a vast, flat plane. If one were to take an equally vast ruler and measure its height, this hemisphere would measure some 6,356.8 kilometers tall. (This happens to be the Earth’s polar radius.)

Suppose that someone were to drive halfway up this hemisphere, some 3,178 kilometers off the ground. This ride would take about 3,340 kilometers. However, if they completed this journey and drive all the way to the North Pole, this second leg – also 3,178 kilometers in height – would take about 6,680 kilometers to complete. (Hope they have enough gas!)

This thought experiment demonstrates one important thing: the higher the latitude, the more circumference one vertical kilometer (or radial kilometer) will cover. The car covered 3340 kilometers of circumference for the first 3178 vertical kilometers, but 6680 kilometers of circumference for the next 3178.

What the Curve Means for Sunlight

If higher latitude means more circumferential distance per radial kilometer, it also means this: the same amount of sunlight must cover more surface as the latitude increases.

Imagine that two 3,178-kilometer tall beams of light strike the lower and upper halves of the Northern Hemisphere, respectively. The beam on the bottom has only 3340 kilometers of circumference to cover, as demonstrated above, but the upper beam must cover 6,680 kilometers. Naturally, the top part of the Hemisphere will not receive as much sun per square kilometer.

This phenomenon is not dependent on the tilt of the earth, which causes the seasons to change. Regardless of the time of year, high-latitude regions will receive less sunlight than equatorial regions due to the heightened curvature of their surface (which forces the same amount of sunlight to cover more area).

This The area of the Earth above the Arctic and Antarctic circles is not perennially cold because of the tilt of the earth (or, for that matter, their distance from the sun). Rather, because these regions have a high ratio of circumferential distance to axial distance, rays of sun hitting the Arctic and Antarctic must cover more space with the same amount of light—meaning, in turn, less light energy is available per square kilometer. This lower density of radial heat is what keeps the polar regions cool.

Certainly, the tilt of the earth and the nature of the polar atmosphere also play a role in determining Arctic temperatures. Nevertheless, it is the earth’s curvature—and the dilution in solar energy resulting thereof—that gives the North and South poles their perpetual chill.

The copyright of the article Why the Arctic is Always Cold in Climatology is owned by Kenneth Burchfiel. Permission to republish Why the Arctic is Always Cold in print or online must be granted by the author in writing.