The situation with California is very unfortunate it has worsened smog, for example, to levels where the state violates EPA pollution standards. While there have been news reports that the drought California is experiencing is the result of human-caused global warming but any such claims are still a matter of dispute.

A February New York Times story sheds some light on the voices of dissent on the issue:

“I’m pretty sure the severity of this thing is due to natural variability,” said Richard Seager, a climate scientist who studies water issues at the Lamont-Doherty Earth Observatory of Columbia University.

To be sure, 2013 was the driest year in 119 years of record keeping in California. But extreme droughts have happened in the state before, and the experts say this one bears a notable resemblance to some of those, including a crippling drought in 1976 and 1977.

The Times report also states:

California has been warming along with most regions of the United States, and temperatures in recent months have been markedly higher than during the 1976-77 drought. In fact, for some of the state’s most important agricultural regions, summer lasted practically into January, with high temperatures of 10 or 15 degrees above normal on some days.

The consequence, scientists say, has been that any moisture the state does get evaporates more rapidly, intensifying the effects of the drought on agriculture in particular. “We are going through a pattern we’ve seen before, but we’re doing it in a warmer environment,” said Michael Anderson, the California state climatologist.

The White House science adviser, John P. Holdren, said in a briefing last week: “Scientifically, no single episode of extreme weather, no storm, no flood, no drought can be said to have been caused by global climate change. But the global climate has now been so extensively impacted by the human-caused buildup of greenhouse gases that weather practically everywhere is being influenced by climate change.”

Even a September Los Angeles Times news report reveals:

In the report, published in the Bulletin of the American Meteorological Society, 20 research teams explored the causes of 16 extreme weather events recorded in 2013, including torrential downpours in Colorado, heat waves in Korea and Australia and a blizzard in South Dakota.

The studies overwhelmingly showed that human-caused climate change played a role in the heat waves, in some cases making them 10 times more likely.

But the report editors wrote that “natural variability likely played a much larger role in the extreme precipitation events,” whether it was flooding in India, deep snow in the Spanish Pyrenees Mountains or the California drought.

Much of California’s water is delivered from the Sierra Nevada mountains resulting from snowfall that takes place there every winter. However, according to policy analyst, author and grape farm owner Victor Davis Hanson, much of the state’s problems is a lack of water infrastructure in which the state has not upgraded its water delivery systems since the 1980’s.