Ice cap

An ice cap is a thick layer of ice that forms over land, usually in high areas. In science, called glaciology, it covers less than 50,000 square kilometers, which is about 19,000 square miles. When ice covers more than this area, it is called an ice sheet instead.

Ice caps are important because they tell us about Earth's climate. They grow when temperatures are cold and shrink when it gets warmer. Studying them helps scientists understand how our planet is changing.

These icy areas are found in cold parts of the world, like near the North and South Poles. They play a big role in keeping Earth cool by reflecting sunlight back into space. As ice caps melt, it can affect sea levels and weather patterns around the globe.

Description

Ice caps are large masses of ice that sit on top of mountains and are not limited by the shape of the land below. They usually have a rounded top centered on the highest point of a mountain area. Ice moves away from this highest point toward the edges of the ice cap.

These ice caps shape the land around them. When they melt, they leave behind features like valleys and lakes, such as the Great Lakes in North America, formed over many thousands of years. Most of the world's ice, about 99%, is found in Antarctica and Greenland, totaling around 33 million cubic kilometers of ice.

Formation

Ice caps form when snow falls during cold weather and does not all melt away when it gets warm. Over many years, this snow piles up and turns into thick, packed snow called perennial firn. Eventually, the snow changes into solid ice.

The shape of an ice cap depends on the land it sits on. The lower parts of an ice cap move outward because of the weight of the ice above, following the shape of the ground below.

Global warming

Ice caps are important signs that show how the Earth is warming up. When the temperature gets higher, ice caps melt faster than they can grow back. Scientists watch ice caps using airplanes and satellites to see how they are changing.

Ice caps gain snow on top and lose snow at the bottom. When everything is balanced, they gain and lose snow at the same rate. But recently, ice caps have been losing more snow than they gain, which helps cause sea levels to rise. Scientists think that if the Earth keeps getting warmer, ice caps will add even more water to the oceans than we thought before.

Variants

See also: Polar ice cap and Ice field

Large areas of ice near the poles, though bigger than the strict definition of an ice cap, are often called polar ice caps. One example of an ice cap is Vatnajökull in Iceland.

Plateau glaciers cover flat highland areas. The ice often flows over the edges as hanging glaciers. An example is Biscayarfonna in Svalbard.