There are approximately 700,000 square kilometers of glaciers and ice sheets in the world located on every continent except Australia. Glaciers typically form in mountains and flow into valleys. They begin to develop when old accumulations of snow transform to ice and begin to build up layer after layer, year after year. As glaciers age, the size of its crystals increase, some growing to be bigger than a baseball. Similarly, there are glacial ice sheets more than 50,000 square kilometers in size that once covered much of the Northern Hemisphere. Today, only two remain and are found in Greenland and Antarctica. Ice sheets are essentially glaciers that have grown so large that their shear size triggers the sheet to flatten and slowly spread out. 

Scientists and decision-makers study glaciers and ice sheets because they are important sources of water and aquatic nutrients, are greatly affected by and influence weather, shape land, can pose a hazard to communities, and contribute to sea-level rise and the health of ocean environments. Researchers can rely on NASA’s glacier and ice sheet data to accurately measure their size and determine how these massive ice giants affect our world.