Mongabay: Feeding the water habits of such major cities as Los Angeles, Las Vegas, and Phoenix, in addition to providing irrigation waters for the entire Southwestern United States, has stretched the Colorado River thin. The river no longer consistently reaches the sea as it once did. Now a new study warns that the Colorado River system, which has proven dependable for human use throughout the 20th Century, may soon experience shortages due to global warming. Two climate researchers at Scripps …