Most scientific accounts of California’s current dry spell link recent low precipitation to naturally occurring atmospheric cycles, not to global warming.
Indeed, most of the global-warming models relied upon by those advocating more-invasive environmental policies predict that warming would leave California with wetter winters — winter precipitation being critical to the snowpack-dependent state — rather than the drier winters at the root of the state’s current water crisis.
What some studies do suggest is that warmer temperatures make the effects of scanty precipitation more intense for California’s end users of water, a reasonably straightforward proposition — higher temperatures will probably contribute to higher demand for water and will certainly contribute to the much more significant problem of evaporation, which steals tremendous amounts of water away from California’s outdated storage-and-conveyance infrastructure and imposes substantial water losses on old-fashioned irrigation systems. …
California has papered over that gap with end-user conservation; the state’s population has doubled since the late 1960s, but its total water consumption is about the same today as it was during the awful drought in the mid-1970s — which means that its per capita water use has been substantially reduced. The inescapable implication is that the low-hanging fruit of water conservation was picked long ago, and that Governor Jerry Brown’s plan to address the crisis through further conservation efforts is likely to prove very difficult to implement.