The Sleeping Bear Glacier of Chile

Grey Glacier, Chile

Part of the Southern Patagonian Ice Field of Chile and Argentina, Grey Glacier covered 104 square miles when it was measured in 1996.

By 2007, when this photograph was taken by astronauts from the International Space Station, the glacier had shrunk considerably, as seen in this comparative false-colour image.

Scientists think increased regional temperatures and changes in the amount of precipitation have led to more ice calving off as free-floating chunks, and less ice being replenished each year.

In the natural-color image above, Grey Glacier looks pale blue because ice absorbs red wavelengths of light and scatters blue. The rough surface of this part of the glacier is caused by vertical cracks in the surface called crevasses, which are formed near the ends of glaciers as the flow of ice at the bottom speeds up relative to the brittle ice on top.

Image: NASA, 2007