Of the eight planets and 293 moons that call our solar system home, only Earth has a surface that sloshes with liquid water. Roughly 71% of the face of our world is covered in seas, lakes, rivers, and oceans, serving as the elixir for more than three billion years of global life. But parts of Earth are not as wet as they used to be, and that’s thanks mostly to the highest of those life forms—us.