The Earth’s water supply in perspective

Viewed from outer space, Earth has been called the Blue Planet. But if you could pull all the water in the ocean, the atmosphere, groundwater and surface water into a ball, it would measure only about 950 miles (1,500 kilometers) in diameter (the large sphere) Only about 3 percent of the world’s water is fresh (the mid-sized sphere); and of that, only one-third is easily accessible to humans (the small sphere). (Illustration by Jack Cook, © Woods Hole Oceanographic Institution)