They have plenty of climate in Europe -- they just haven't become reliant on a single state that's going to be in extreme drought for at least the next decade for all their produce during the winter months. See, for example, Magnus Nilsson's talk at Google regarding how he produces nearly all his own vegetables at his restaurant in northern Sweden: https://www.youtube.com/watch?v=FEMdhX3gtCY
I think you're hinting about the Pacific Decadal Oscillation, which is associated with drier weather in California (this makes sense intuitively, since a cooler Pacific ocean near California means less energy to evaporate sea water, which means less moisture in the air, which means less rain).
This oscillation in northern Pacific sea surface temperatures has a frequency of 30-50 years, so we'll probably be in the cool/dry phase for some time.
However, given the variable nature of climate and a host of other oscillations and trends that are occurring at the same time, it's irresponsible to forecast "extreme drought for at least the next decade" based on this single signal. For example, forecasters are predicting El Niño this fall, which is a (generally) stronger signal than the PDO, and is statistically associated with wetter weather in California.
You're definitely correct in worrying about the water situation in California, though. Population pressures, groundwater depletion, and climate effects all point to significant water resource pressure for the state in the foreseeable future. This will translate into higher food prices, as farming is a major use of water in the state.
It'll be interesting to see whether the drought impacts Californians as much as the rest of the country. Our drought is really, really bad but California is one of the wealthier states with the largest population and an absurd share of the United Stats' agricultural production [1]. With a lot of our industrial meat production backed by corn from other states, our exports might suffer more than total agricultural production (18.8 out of >45 billion dollars)
