2. For a planet where water covers 70 percent of the surface, Earth certainly makes its residents work hard for a drink. Aside from fish and other saltwater-sipping sea life, most of us have to share what little freshwater we can find on land. And that's no small task. Only 3 percent of all water on Earth is freshwater, more than two-thirds of which is locked up in glaciers and ice caps. Of the other third, barely a trickle collects on the surface — lakes, rivers, streams and swamps represent less than 0.5 percent of all freshwater worldwide.