Geography of Greenland
Some parts of North Greenland are not covered by the huge inland ice cap. The area is the northernmost ice-free region in the world. The amount of precipitation is so low that it is referred to as a polar desert.
Photo: Peter Prokosch
Rugged coastlines, dramatic fjords, glaciers, and Arctic wildlife dominate the landscape of Greenland.
Greenland is mountainous beneath its ice sheet. The island's bedrock is a complex terrain of mountains, deep valleys, and ancient fjords.
The coastal areas, especially in the east and southeast, have rugged mountain ranges. These are some of the oldest rocks on Earth, part of the ancient cratons that form Greenland's geological core.
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In the interior, the ice has flattened and depressed the land over time due to its enormous weight. But scientists using radar and gravity mapping have found basins and ridges there too.
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The highest peak on the island is
Gunnbjørn Fjeld at 3,694 m (12,119 ft). It is located on the east coast of Greenland and is the
highest mountain north of the
Arctic Circle.
Greenland Ice Sheet
Greenland's ice sheet with supraglacial streams, rivers, and lakes.
Photo: Bernt Rostad
The island lies beneath a flat to gradually sloping
ice sheet that covers all but a narrow, mountainous, rocky coast. Greenland's ice sheet originated during the
Ice Ages of the
Pleistocene Epoch, when Earth's climate cooled dramatically.
The icecap has an area of
1.75 million km² (almost the size of Mexico), with an average thickness of 2.3 km (1.4 mi), and holds estimated 7 percent of the world's freshwater. Greenland's more than fifty
glaciers move ice steady from the interior of the territory to the coast of the North Atlantic, where it breaks off as
icebergs and eventually melt into the ocean.
Greenland's ice sheet has been one of the largest contributors to global sea-level rise over the past 20 years. A significant portion of this contribution is associated with the speed-up of an increased number of glaciers in southeast and northwest Greenland.
From 1996 to 2005 the velocity of many of Greenland's glaciers increased from 90 cubic km (22 cubic miles) per year to 220 cubic km (53 cubic miles) per year.
[NASA]
As temperatures around the world slowly climb, meltwaters from these vast stores of ice add to rising sea levels. Greenland could raise the sea level by 7 meters (23 feet) if its ice melted completely. If the ice melted completely, we would be surprised by the fact that Greenland is not one but made up of two or three islands surrounding a vast sea.
Greenland's rivers
Surface rivers on Greenland are seasonal, mostly forming during summer when the ice sheet melts. These meltwater rivers often flow on top of the ice, cutting twisting blue channels through the snow. Some of streams suddenly vanish into
moulins — vertical shafts that funnel the water deep inside the glacier, straight down to the bedrock.
Scientists believe there are
hidden subglacial rivers and lakes beneath the ice sheet, kept liquid by geothermal heat and pressure.