It’s no secret that Earth is a wet and wild place—from grade school onward, most people can readily cite the fact that water covers about 70 percent of the planet’s surface. And images taken from space show our home world as a “blue marble” awash in oceans, rivers and lakes.
But life on Earth depends on a lot of water that we can’t see, from vapor in the air we breathe to freshwater in deep aquifers used to irrigate crops. Figuring out where this water came from, where it is now, how it moves around and how humans are affecting its flow will be critical to management of this most precious resource. Read more