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

Can extreme melt destabilize ice sheets?

Nearly a decade ago, global news outlets reported vast ice melt in the Arctic as sapphire lakes glimmered across the previously frozen Greenland Ice Sheet, one of the most important contributors to sea-level rise. Now researchers ...

What a glacial river reveals about the Greenland Ice Sheet

With data from a 2016 expedition, scientists supported by NASA are shedding more light into the complex processes under the Greenland Ice Sheet that control how fast its glaciers slide toward the ocean and contribute to sea ...

Microplastics are affecting melt rates of snow and ice

Microplastics have reached the farthest corners of the Earth, including remote fjords and even the Mariana Trench, one of the deepest parts of the ocean. Recently, yet another distant area of our planet has been found to ...

Melting ice sheets caused sea levels to rise up to 18 meters

It is well known that climate-induced sea level rise is a major threat. New research has found that previous ice loss events could have caused sea-level rise at rates of around 3.6 meters per century, offering vital clues ...

Ancient fish DNA provides a window back in time

The accidental discovery of fossilized three-spine stickleback bones dating back 12 thousand years, has enabled scientist to confirm parallel evolution, or evolutionary changes or adaptions which take place repeatedly.

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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