page_title: Subglacial lake
section_title: History and expeditions
hierarchical_section_title: Subglacial lake / History and expeditions
caption_attribution_description: Peter Kropotkin circa 1900
context_page_description: A subglacial lake is a lake that is found under a glacier, typically beneath an ice cap or ice sheet. Subglacial lakes form at the boundary between ice and the underlying bedrock, where gravitational pressure decreases the pressure melting point of ice. Over time, the overlying ice gradually melts at a rate of a few millimeters per year. Meltwater flows from regions of high to low hydraulic pressure under the ice and pools, creating a body of liquid water that can be isolated from the external environment for millions of years.
  Since the first discoveries of subglacial lakes under the Antarctic Ice Sheet, more than 400 subglacial lakes have been discovered in Antarctica, beneath the Greenland Ice Sheet, and under Iceland's Vatnajökull ice cap. Subglacial lakes contain a substantial proportion of Earth's liquid freshwater, with the volume of Antarctic subglacial lakes alone estimated to be about 10,000 km³, or about 15% of all liquid freshwater on Earth.
  As ecosystems isolated from Earth's atmosphere, subglacial lakes are influenced by interactions between ice, water, sediments, and organisms.
context_section_description: Russian revolutionary and scientist Peter A. Kropotkin first proposed the idea of liquid freshwater under the Antarctic Ice Sheet at the end of the 19th century. He suggested that due to the geothermal heating at the bottom of the ice sheets, the temperature beneath the ice could reach the ice melt temperature, which would be below zero. The notion of freshwater beneath ice sheets was further advanced by Russian glaciologist Igor A. Zotikov, who demonstrated via theoretical analysis the possibility of a decrease in Antarctic ice because of melting of ice at a lower surface. As of 2019, there are over 400 subglacial lakes in Antarctica, and it is suspected that there is a possibility of more. Subglacial lakes have also been discovered in Greenland, Iceland, and northern Canada.
caption: Russian scientist Peter Kropotkin first proposed the idea of fresh water under Antarctic ice.
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