Jääkerroksia

Jääkerroksia, often translated as ice sheets or ice caps, are large masses of ice that form when snow accumulates over many years in frigid regions and compresses into thick layers. These formations are distinct from glaciers, which are typically smaller and confined to mountainous areas. Ice sheets are continental in scale, covering vast land areas.

The two largest ice sheets on Earth today are the Antarctic Ice Sheet and the Greenland Ice Sheet. The Antarctic Ice Sheet is the largest single mass of ice on Earth, covering an area of about 14 million square kilometers and containing approximately 70% of the world's freshwater. The Greenland Ice Sheet is the second largest, covering about 1.7 million square kilometers, or 80% of Greenland's surface.

The formation of ice sheets is a slow process that can take thousands to millions of years. Snowfall in these regions is often very light, but because temperatures are consistently below freezing, the snow never melts. Over time, the weight of the accumulating snow compresses the lower layers into ice. As the ice sheet grows, it can deform and flow outwards under its own weight, similar to a very slow-moving river.

Ice sheets play a crucial role in regulating Earth's climate. They reflect a significant amount of solar radiation back into space, contributing to the planet's albedo effect, which helps keep the Earth cool. The melting of ice sheets, particularly in response to global warming, is a significant contributor to sea-level rise. Scientists monitor ice sheets to understand past climate conditions and to predict future changes in sea level and climate.