mannerjäätiköiden

Mannerjäätiköt, often translated as ice sheets, are vast, continuous masses of ice that cover large areas of land. They are distinct from smaller glaciers, which are typically confined to mountain valleys or cirques. Ice sheets are so extensive that they can bury entire mountain ranges and reshape the underlying topography over geological timescales.

Currently, the Earth has two major ice sheets: the Antarctic ice sheet and the Greenland ice sheet. The Antarctic ice sheet is by far the largest, covering nearly the entire continent of Antarctica and containing an estimated 90% of the world's freshwater ice. The Greenland ice sheet is the second largest and covers most of Greenland.

The formation of ice sheets begins when snow accumulates over many years in polar or high-altitude regions. As more snow falls, the weight of the upper layers compresses the lower layers into ice. Over time, this process can create ice masses thousands of meters thick. The immense pressure causes the ice to flow slowly outwards from the center of accumulation, similar to a very viscous liquid. This outward flow is what shapes the landscape beneath the ice sheet, carving out valleys and fjords.

Ice sheets play a critical role in the Earth's climate system. They reflect a significant amount of solar radiation back into space, helping to regulate global temperatures. Changes in the size and volume of ice sheets, particularly melting, have a direct impact on global sea levels. Monitoring these changes is therefore crucial for understanding and predicting future climate scenarios.