Travel to the world: Ice Canyon

By paffy on May 15, 2013 Category: Pics, Travel

The ice canyons in Greenland were carved by meltwater and are as deep as 150 feet.

Outline map of Greenland with ice sheet depths. GISP2 refers to a main site of theGreenland Ice Sheet Project, where a 3 km deep ice core was taken.

The Greenland ice sheet (Greenlandic: Sermersuaq) is a vast body of ice covering 1,710,000 square kilometres (660,235 sq mi), roughly 80% of the surface of Greenland. It is the second largest ice body in the world, after theAntarctic Ice Sheet. The ice sheet is almost 2,400 kilometres (1,500 mi) long in a north-south direction, and its greatest width is 1,100 kilometres (680 mi) at a latitude of 77°N, near its northern margin. The mean altitude of the ice is 2,135 metres (7,005 ft).[1] The thickness is generally more than 2 km (1.24 mi) and over 3 km (1.86 mi) at its thickest point. It is not the only ice mass of Greenland – isolated glaciers and small ice caps cover between 76,000 and 100,000 square kilometres (29,344 and 38,610 sq mi) around the periphery. Some scientists predict that climate change may be near a "tipping point" where the entire ice sheet will melt in about 2000 years.[2] If the entire 2,850,000 cubic kilometres (683,751 cu mi) of ice were to melt, it would lead to a global sea level rise of 7.2 m (23.6 ft).[3]

The Greenland Ice Sheet is also sometimes referred to under the term inland ice, or its Danish equivalent,indlandsis. It is also sometimes referred to as an ice cap. "Ice sheet" is considered the more correct term, as "ice cap" generally refers to less extensive ice masses.[citation needed]

The ice in the current ice sheet is as old as 110,000 years.[4] The presence of ice-rafted sediments in deep-sea cores recovered off of northeast Greenland, in the Fram Strait, and south of Greenland indicated the more or less continuous presence of either an ice sheet or ice sheets covering significant parts of Greenland for the last 18 million years. From just before 11 million years ago to a little after 10 million years ago, the Greenland Ice Sheet appears to have been greatly reduced in size. The Greenland Ice Sheet formed in the middle Miocene by coalescence of ice caps and glaciers. There was an intensification of glaciation during the Late Pliocene.[5]

The ice sheet as a record of past climates [edit]

The ice sheet, consisting of layers of compressed snow from more than 100,000 years, contains in its ice today's most valuable record of past climates. In the past decades, scientists have drilled ice cores up to 4 kilometres (2.5 mi) deep. Scientists have, using those ice cores, obtained information on (proxies for) temperature, ocean volume, precipitation, chemistry and gas composition of the lower atmosphere, volcanic eruptions, solar variability, sea-surface productivity, desert extent and forest fires. This variety of climatic proxies is greater than in any other natural recorder of climate, such as tree rings or sediment layers.

Meltwater, which moves to the sea under the ice in contact with the land surface, may transport solids or dissolved material such as iron to the ocean. Measurements of the amount of available iron in meltwater from the Greenland ice sheet shows that extensive melting of the ice sheet might add an amount of iron to the Atlantic Ocean equivalent to that added by airborne dust. This would increase biological activity in the Atlantic.^[14]

Until 2007, rate of decrease in ice sheet height in cm per year.
Modelling results of the sea-level rise under different warming scenarios.
Satellite image of dark blue melt ponds.
Albedo change in Greenland

Recent ice loss events [edit]

Between 2000 and 2001: Northern Greenland's Petermann glacier lost 33 square miles (85 km²) of floating ice.
Between 2001 and 2005: Sermeq Kujalleq broke up, losing 36 square miles (93 km²) and raised awareness worldwide of glacial response to global climate change.^[15]
July 2008: Researchers monitoring daily satellite images discovered that a 11-square-mile (28 km²) piece of Petermann broke away.
August 2010: A sheet of ice measuring 260 square kilometres (100 sq mi) broke off from the Petermann Glacier. Researchers from the Canadian Ice Service located the calving from NASA satellite images taken on August 5. The images showed that Petermann lost about one-quarter of its 70 km-long (43 mile) floating ice shelf.^[16]
July 2012: An iceberg twice the size of Manhattan (100 square mi) broke away from the Petermann glacier in northern Greenland.^[17]