Lake Mead May Vanish by 2021

Lake Mead, the giant man-made lake behind the Hoover Dam and a major source of water for millions of people, is rapidly drying up, reports Live Science. A new study predicts a  50% chance the lake will be too low to produce hydroelectric power by 2017, and a 50% chance that it will vanish by 2021.

Global warming and increasing demand are being blamed. "We were stunned at the magnitude of the problem and how fast it was coming at us," said an author of the study. "Make no mistake, this water problem is not a scientific abstraction, but will impact each and every one of us who live in the Southwest." (More Lake Mead stories.)