These awe-inspiring images of glaciers are helping scientists to determine just how quickly our planet is heating up. The huge ice fields are thought to be one of the most reliable indicators of climate change and are best studied from space.

The features form when snow accumulates on an area of land over tens to hundreds of years. It eventually becomes so thick and heavy that it forms dense glacial ice. When enough ice is compacted it beings to flow downhill or spread across flat land.