The Guardian: "Global warming and drought are turning the Golden State brown"

"Another study finds that drought will hit California hard as the planet keeps warming"

Link to web site

"There's a rapidly growing body of scientific research finding that California is in the midst of its worst drought in over a millennium, global warming has made the drought worse, and decades-long mega-droughts could become the norm in the state later this century. A new study published in the Proceedings of the National Academy of Science (PNAS) by scientists at Stanford University adds to this bleak picture for the Golden State.

There has been some confusion about the human contribution to California's drought, now entering its fourth consecutive year, because some reports have said that humans have not influenced the amount of precipitation falling in the state thus far. This is a subject of debate – some studies have found evidence of a human 'fingerprint' in the high pressure ridge that's diverted storms away from California over the past three years. But overall, while precipitation has been low, there have been a few years in the historical record where it was lower.