Tuesday, February 2, 2016

Greenland


Greenland is the world's largest non-continental island[55] and the third largest country in North America.[56] It lies between latitudes 59° and 83°N, and longitudes 11° and 74°W. The Atlantic Ocean borders Greenland's southeast; the Greenland Sea is to the east; the Arctic Ocean is to the north; and Baffin Bay is to the west. The nearest countries are Canada, to the west across Baffin Bay, and Iceland, east of Greenland in the Atlantic Ocean. Greenland also contains the world's largest national park, and it is the largest dependent territory by area in the world.

The average daily temperature of Nuuk, Greenland varies over the seasons from −8 to 7 °C (18 to 45 °F).

The total area of Greenland is 2,166,086 km2 (836,330 sq mi) (including other offshore minor islands), of which the Greenland ice sheet covers 1,755,637 km2 (677,855 sq mi) (81%) and has a volume of approximately 2,850,000 km3 (680,000 cu mi).[57] The highest point on Greenland is Gunnbjørn Fjeld at 3,700 m (12,139 ft) of the Watkins Range (East Greenland mountain range). The majority of Greenland, however, is less than 1,500 m (4,921 ft) in elevation.


The weight of the ice sheet has depressed the central land area to form a basin lying more than 300 m (984 ft) below sea level,[58][59] while elevations rise suddenly and steeply near the coast.[60] The ice flows generally to the coast from the centre of the island. A survey led by French scientist Paul-Emile Victor in 1951 concluded that, under the ice sheet, Greenland is composed of three large islands.[61] This is disputed, but if it is so, they would be separated by narrow straits, reaching the sea at Ilulissat Icefjord, at Greenland's Grand Canyon and south of Nordostrundingen.

All towns and settlements of Greenland are situated along the ice-free coast, with the population being concentrated along the west coast. The northeastern part of Greenland is not part of any municipality, but it is the site of the world's largest national park, Northeast Greenland National Park.


View of mountains on Greenland from the air

At least four scientific expedition stations and camps had been established on the ice sheet in the ice-covered central part of Greenland (indicated as pale blue in the map to the right): Eismitte, North Ice, North GRIP Camp and The Raven Skiway. Currently, there is a year-round station, Summit Camp, on the ice sheet, established in 1989. The radio station Jørgen Brønlund Fjord was, until 1950, the northernmost permanent outpost in the world.

The extreme north of Greenland, Peary Land, is not covered by an ice sheet, because the air there is too dry to produce snow, which is essential in the production and maintenance of an ice sheet. If the Greenland ice sheet were to melt away completely, the world's sea level would rise by more than 7 m (23 ft).

Between 1989 and 1993, US and European climate researchers drilled into the summit of Greenland's ice sheet, obtaining a pair of 3 km (1.9 mi) long ice cores. Analysis of the layering and chemical composition of the cores has provided a revolutionary new record of climate change in the Northern Hemisphere going back about 100,000 years, and illustrated that the world's weather and temperature have often shifted rapidly from one seemingly stable state to another, with worldwide consequences. The glaciers of Greenland are also contributing to a rise in the global sea level at a faster rate than was previously believed. Between 1991 and 2004, monitoring of the weather at one location (Swiss Camp) showed that the average winter temperature had risen almost 6 °C (11 °F). Other research has shown that higher snowfalls from the North Atlantic oscillation caused the interior of the ice cap to thicken by an average of 6 cm or 2.36 in/yr between 1994 and 2005. However, a recent study suggests a much warmer planet in relatively recent geological times:

Scientists who probed 2 km (1.2 mi) through a Greenland glacier to recover the oldest plant DNA on record said that the planet was far warmer hundreds of thousands of years ago than is generally believed. DNA of trees, plants, and insects including butterflies and spiders from beneath the southern Greenland glacier was estimated to date to 450,000 to 900,000 years ago, according to the remnants retrieved from this long-vanished boreal forest. That view contrasts sharply with the prevailing one that a lush forest of this kind could not have existed in Greenland any later than 2.4 million years ago. These DNA samples suggest that the temperature probably reached 10 °C (50 °F) in the summer and −17 °C (1.4 °F) in the winter. They also indicate that during the last interglacial period, 130,000–116,000 years ago, when local temperatures were on average 5 °C (9 °F) higher than now, the glaciers on Greenland did not completely melt away.

In 1996, the American Top of the World expedition found the world's northernmost island off Greenland: ATOW1996. An even more northerly candidate was spotted during the return from the expedition, but its status is yet to be confirmed.

In 2007 the existence of a new island was announced. Named "Uunartoq Qeqertaq" (English: Warming Island), this island has always been present off the coast of Greenland, but was covered by a glacier. This glacier was discovered in 2002 to be shrinking rapidly, and by 2007 had completely melted away, leaving the exposed island. The island was named Place of the Year by the Oxford Atlas of the World in 2007. Ben Keene, the atlas's editor, commented: "In the last two or three decades, global warming has reduced the size of glaciers throughout the Arctic and earlier this year, news sources confirmed what climate scientists already knew: water, not rock, lay beneath this ice bridge on the east coast of Greenland. More islets are likely to appear as the sheet of frozen water covering the world's largest island continues to melt".


Some controversy surrounds the history of the island, specifically over whether the island might have been revealed during a brief warm period in Greenland during the mid-20th century.


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