Aerosol pollutants, tiny particles from incomplete burning of fossil fuels, forests, and other combustibles, also cause Arctic warming. Warming is started by increased atmospheric concentrations of greenhouse gases, such as carbon dioxide and methane. The Arctic has been particularly vulnerable to global warming. Rainfall patterns in the Northern Hemisphere and the livelihoods of humans and animals living in the Arctic are also strongly influenced by the Arctic ice. This denser, saltier water then sinks, helping to force the global ocean conveyor. When seawater freezes in the winter, it rejects salt into the water, increasing the ocean's local density. It reflects solar energy back into space like a mirror, thus helping control circulation of water in the oceans via the North Atlantic branch of the Great Conveyor Belt or thermohaline overturning circulation by which all the oceans of the world remain in constant cyclic motion. The Arctic sea- ice cap is an important part of the global climate system. Infrared radiation emitted by all objects reveals the object's temperature, so infrared observations from space have allowed tracking of temperatures all over the Arctic since 1979. Satellite data was first obtained from the Landsat satellites in the late 1970s. However, simultaneous observing of the whole region is practical only from orbit. The North Pole has since been visited by many expeditions, including nuclear-powered submarines, aircraft, adventurers on foot, and icebreakers.įor decades, scientific knowledge of the Arctic depended on aircraft and ground stations. This was finally achieved in 1909 by American engineer and explorer Robert E. The Arctic interior was first explored by Europeans in the nineteenth century, when a number of expeditions tried to reach the North Pole itself. Historical Background and Scientific FoundationsĪlthough indigenous peoples such as the Inuit (Eskimos) have inhabited the region around the Arctic for thousands of years, they had no reason or ability to reach its more isolated areas, such as the vicinity of the North Pole or the interior of the Greenland ice cap. Within a few decades the Arctic may be completely ice-free in summer. The Arctic has been more strongly affected by climate change than any other region except the western peninsula of Antarctica, and in recent years has shown rapid thinning of its ice and reduction of its ice area, especially in summer. This patch of floating ice expands and contracts with the seasons. The North Pole is covered by ocean that is skinned over by frozen seawater. The South Pole is occupied by a large continent, Antarctica, which bears a thick ice sheet containing about 90% of all the ice on Earth. The North and South Poles of Earth are both covered with ice because the light of the sun strikes them at a glancing angle or not at all, depending on the time of year. Arctic Melting: Polar Ice Cap Introduction
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