Polar Regions

Polar regions are defined as the areas around the two poles of the Earth: the Northern Polar Region (Arctic) and the Southern Polar Region (Antarctic). They are the places farthest from the equator, where sunlight strikes at a low angle throughout the year, reducing the amount of solar energy that reaches the surface.

Both polar regions share certain characteristics: extreme cold, ice and sea ice, and periods of daylight that vary greatly over the course of the year. However, their physical structures differ: the Arctic consists largely of frozen ocean surrounded by continents, while the Antarctic is a continent of land covered in ice, surrounded by ocean.

Geographic Boundaries

The conventional method defines polar regions by the Arctic and Antarctic circles—the Northern and Southern latitude lines marking the polar boundaries. Within these areas there is at least one day when the sun does not set (midnight sun) and one day when it does not rise. Some scientists instead base the boundary on summer temperature or tree line limits, which do not follow latitude lines alone.

Climate and Ice

White ice reflects most of the sun's light (high albedo), which intensifies the cold. Sea ice in the Arctic expands in winter and shrinks in summer. Antarctica lies beneath a thick ice sheet that holds a large portion of the world's fresh water. Climate change is measured partly by its effect on ice extent and sea temperatures.

Life and People

Polar life depends on the sea: animals such as polar bears, seals, and seabirds in the north; penguins, seals, and whales in the south. The Arctic is inhabited by indigenous peoples whose cultures and economies are based on hunting and fishing. Antarctica has no permanent human population; it contains research stations operated by governments.

Governance

Antarctica is governed by an international treaty that designates the continent for peaceful purposes and scientific research, while prohibiting territorial claims. The Arctic lies within the boundaries of different nations, and governance of regional issues, shipping, and resources is coordinated among them.