And water, which is becoming more and more scarce

Carve out a giant semi-cone into the oceanside, acting as a static water inlet/basin.

Line surface area of cone w/heavy mirror array. Desalinate thru concentrated sunbeams.

Or something like that.

They are building giant solar desalinators in Saudi Arabia so this is maybe not far from the truth. https://wired.me/science/environment/desalination-solar-dome...

I'm not sure what they're attempting to describe in the article but so far seems to me like a child's toy compared to a proper multi-stage flash distillation plant (which uses multiple stages and decreased pressures at each stage to massively decrease energy requirements) -- and even those should use more energy than reverse osmosis plants.

Getting water from the sea up to the desert would be a huge challenge in California, and right on the coast isn’t very sunny for most of it.

California zoning laws wouldn’t allow that. And changing it would take decades of bureaucracy.

I wish I was joking.