The Earth currently has two ice sheets, one in Antarctica and one in Greenland. These ice sheets are continental-scale masses of ice that cover a large portion of the Earth's surface, but there are also smaller ice complexes like icefields and ice caps. Most of the world's permanent ice is found in these ice sheets and glaciers. The Antarctic Ice Sheet is the largest of these, covering an area of 14 million km2 and containing 30 million km3 of ice. Recently, research has shown that even the East Antarctica Ice Sheet, previously thought to be less vulnerable, is being affected by climate change. NASA's GRACE and GRACE Follow-On satellites provide data on the state of the ice sheets in Antarctica and Greenland.