I would note that Isreal has a total land area of around 21,000 km^2. California has 400,000 km^2 of land, and has about 175,000 km^2 of of agricultural land a

I would note that Isreal has a total land area of around 21,000 km^2. California has 400,000 km^2 of land, and has about 175,000 km^2 of of agricultural land alone. While there is sure to be something to be learned from the Israeli experience, there's no reason to believe that those lessons scale to the size of the problem CA has. In particular, things like use of greenhouses on commiserate scale is probably infeasible.