Canadian Press: Here’s a global warming wake-up call for thirsty people in the southwestern United States: Scientists say Lake Mead is in danger of drying up. The dammed-up lake along the Colorado River spans the border between Nevada and Arizona and is the largest water reservoir in the U.S. West. It and Lake Powell help provide water for more than 25 million people in seven states. But because of a combination of climate change and strong demand, it could be completely drained by the …