Related topics: climate change · glaciers · sea level rise · sea level · ice

Video: The latest science on tipping points in Antarctica

Ice loss from Antarctica has increased over the recent decades. The ice sheet in this remote continent covers about 98% of the Antarctic continent and is the largest single mass of ice on Earth. Even small changes in ocean ...

DNA reveals that unique microorganisms evolved at poles

Communities of microorganisms at the bottom of polar lakes evolved independently from other regions, influenced by the particular geological, biological, and climate history of their regions. The unique character of the microbial ...

Greenland Climate Network measurement series reprocessed

For 30 years, researchers operated a network of weather stations on Greenland in harsh conditions. The dataset from this highly relevant climate research has now been reprocessed and published in an article in Earth System ...

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Ice sheet

An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 km² (20,000 mile²). The only current ice sheets are in Antarctica and Greenland; during the last glacial period at Last Glacial Maximum (LGM) the Laurentide ice sheet covered much of Canada and North America, the Weichselian ice sheet covered northern Europe and the Patagonian Ice Sheet covered southern South America.

Ice sheets are bigger than ice shelves or glaciers. Masses of ice covering less than 50,000 km2 are termed an ice cap. An ice cap will typically feed a series of glaciers around its periphery.

Although the surface is cold, the base of an ice sheet is generally warmer due to geothermal heat. In places, melting occurs and the melt-water lubricates the ice sheet so that it flows more rapidly. This process produces fast-flowing channels in the ice sheet — these are ice streams.

The present-day polar ice sheets are relatively young in geological terms. The Antarctic Ice Sheet first formed as a small ice cap (maybe several) in the early Oligocene, but retreating and advancing many times until the Pliocene, when it came to occupy almost all of Antarctica. The Greenland ice sheet did not develop at all until the late Pliocene, but apparently developed very rapidly with the first continental glaciation. This had the unusual effect of allowing fossils of plants that once grew on present-day Greenland to be much better preserved than with the slowly forming Antarctic ice sheet.

This text uses material from Wikipedia, licensed under CC BY-SA