Last Glacial Maximum
Channel: the aleatoric learning channel
Date: 2021-12-12

The Last Glacial Maximum, also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent. Ice sheets covered much of North America, Northern Europe, and Asia and profoundly affected Earth's climate by causing drought, desertification, and a large drop in sea levels. Growth of ice sheets commenced 33,000 years ago and maximum coverage was between 26,500 years and 19-20,000 years ago, when deglaciation commenced in the Northern Hemisphere, causing an abrupt rise in sea level. Decline of the West Antarctica ice sheet occurred between 14,000 and 15,000 years ago, consistent with evidence for another abrupt rise in the sea level about 14,500 years ago. The formation of an ice sheet or ice cap requires both prolonged cold and precipitation. In northwestern Russia the Fennoscandian Ice Sheet reached its LGM extent 17 ka BP, five thousand years later than in Denmark, Germany and Western Poland. Outside the Baltic Shield, and in Russia in particular, the LGM ice margin of the Fennoscandian Ice Sheet was highly lobate. Permafrost covered Europe south of the ice sheet down to present-day Szeged in Southern Hungary. Ice covered Ireland and almost all of Wales, with the southern boundary of the ice sheet running approximately from the current location of Cardiff north-north-east to Middlesbrough, and then across Doggerland to Denmark. In addition to the large Cordilleran Ice Sheet in Canada and Montana, alpine glaciers advanced and ice caps covered much of the Rocky and Sierra Nevada Mountains further south. In the Southern Hemisphere, the Patagonian Ice Sheet covered the whole southern third of Chile and adjacent areas of Argentina. On the western side of the Andes the ice sheet reached sea level as far north as in the 41 degrees south at Chacao Channel.