The Greenland Ice Sheet is the second largest mass of ice on Earth and is about one-tenth the volume of the Antarctic Ice Sheet. Today it is the only significant ice mass in the Arctic. [See Antarctica and climate change; and ice caps.] It is an Ice Age relic that covers a bowl-shaped continent almost completely surrounded by coastal mountains. PHYSICO-GEOGRAPHIC ENVIRONMENT The ice sheet extends from approximately 60° to 83° N over a distance of 2,400 km in the North Atlantic Ocean. The ice sheet covers 1.71 million km2, or about 80% of Greenland's surface. It consists of a northern dome and a southern dome, with maximum altitudes of 3,230 m and 2,850 m respectively, connected by a long saddle with altitudes around 2,500 m. Its total volume is approximately 2.85 million km3, which, if it were to melt completely, would raise global sea levels by approximately 7.2 m. The ice sheet has an average thickness of 1,670 m and reaches a maximum of 3,300 m in the center. The bedrock surface beneath the ice sheet is a large flat area near sea level, which would rise up to 1,000 m if the ice sheet were removed (Figure 1). Precipitation over Greenland generally decreases from south to north, varying from about 2,500 mm per year in the southeast to less than 150 mm per year in the interior of northeastern Greenland. The southern area of ​​high precipitation is largely determined by Icelandic lows and the resulting overland flow that is forced up to the surface of the ice sheet. Unlike Antarctica, summer temperatures in Greenland are high enough to cause widespread summer melting. This results in a negative mass balance ablation zone around its perimeter. Ablation rates are highest in the southwestern part of the ice sheet where... middle of paper... may not return to normal conditions, in which case the disappearance of the Greenland ice sheet and associated sea The increase of the level may be irreversible. For this reason, the Greenland Ice Sheet is often described as a relict ice mass. It survived the current Holocene interglacial period solely because it creates its own cold surface climate due to its elevation. The last time Greenland temperatures were several degrees higher than today was the last interglacial period, 125,000 years ago. Ice core evidence for a smaller ice sheet is consistent with the observation that sea level then was several meters higher than today. At that time the ice sheet did not disappear completely, probably because the warming was not strong enough and did not last long enough. The ice sheet was probably saved from extinction by the start of the last glacial period, several thousand years later.