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

24 percent of West Antarctic ice is now unstable: study

By combining 25 years of European Space Agency satellite altimeter measurements and a model of the regional climate, the UK Centre for Polar Observation and Modelling (CPOM) have tracked changes in snow and ice cover across ...

Drilling the seabed below Earth's most powerful ocean current

The Antarctic Circumpolar Current is the planet's most powerful and arguably most important. It is the only one to flow clear around the globe without getting diverted by any landmass, sending up to 150 times the flow of ...

Image: Antarctica detailed in 3-D

Unfortunately ice is a hot topic when it comes to understanding and monitoring how this fragile component of the Earth system is being affected by climate change. Scientists, therefore, go to great lengths to study changes ...

Antarctica's effect on sea level rise in coming centuries

There are two primary causes of global mean sea level rise - added water from melting ice sheets and glaciers, and the expansion of sea water as it warms. The melting of Antarctica's ice sheet is currently responsible for ...

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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