Dye 3 - Greenland Ice Sheet

Greenland Ice Sheet

The 'Greenland ice sheet' (Kalaallisut: Sermersuaq) is a vast body of ice covering 1.71 million km2, roughly 80% of the surface of Greenland. It is the second largest ice body in the World, after the Antarctic Ice Sheet. The ice sheet is almost 2,400 kilometers long in a north-south direction, and its greatest width is 1,100 kilometers at a latitude of 77°N, near its northern margin. The mean altitude of the ice is 2,135 meters.

The ice in the current ice sheet is as old as 110,000 years. However, it is generally thought that the Greenland Ice Sheet formed in the late Pliocene or early Pleistocene by coalescence of ice caps and glaciers. It did not develop at all until the late Pliocene, but apparently developed very rapidly with the first continental glaciation.

The ice surface reaches its greatest altitude on two north-south elongated domes, or ridges. The southern dome reaches almost 3,000 metres at latitudes 63°–65°N; the northern dome reaches about 3,290 metres at about latitude 72°N. The crests of both domes are displaced east of the centre line of Greenland. The unconfined ice sheet does not reach the sea along a broad front anywhere in Greenland, so that no large ice shelves occur.

On the ice sheet, temperatures are generally substantially lower than elsewhere in Greenland. The lowest mean annual temperatures, about −31 °C (−24 °F), occur on the north-central part of the north dome, and temperatures at the crest of the south dome are about −20 °C (−4 °F).

During winter, the ice sheet takes on a strikingly clear blue/green color. During summer, the top layer of ice melts leaving pockets of air in the ice that makes it look white. Positioned in the Arctic, the Greenland ice sheet is especially vulnerable to global warming. Arctic climate is now rapidly warming.