California's ongoing drought is a result of natural variability, at least for the 2013–14 period. But the state could see larger swings in wet and dry seasons by the end of this century owing to climate change.

Neil Berg and Alex Hall of the University of California, Los Angeles, used 34 climate models to study how precipitation extremes might change in California. They expect that between 2060 and 2100, the normally wet winter will be extremely dry twice as often as today, and extremely wet three times as often. The fluctuations could raise the risk of drought and flooding.

These changes could push the state's water supply to its limit.

J. Clim. http://doi.org/4fz (2015)