Absolutely, we need to look to Israel, also a country within a desert: https://www.scientificamerican.com/article/israel-proves-the...

Israel desalinates more water than it uses and is a net exporter of water in the region, selling fresh water to other countries.

Very interesting article. However, it only talks about drinking water and the real problem is water for agriculture and the author doesn’t talk much about cost of desalinated water vs cost of acquirer water. My own professional experience suggests desal water is cost-effective within sophisticated fertigation, controlled-environment systems which produce high value crops, but probably not for the more expansive wheat, maize, rice systems we use to grow our staples and animal feeds. Maybe we’ll be able to achieve this in an era of renewables.

Wouldn't it be easier to take the farms to where the water is, rather than bring the water here?

The grandfathering of water use rights from 100 years ago and the political clout of rural areas guaranteed by the typical state/federal senate apportioning makes this extremely difficult to turn around from having the farms in the desert in California and Arizona. How do we fix that?

Farms need a lot more than water, though. They need square footage, soil quality, suitable climate, access to infrastructure for shipping, and a good amount of cheap labor. All of those (except, increasingly, cheap labor) can be found in California.

With cheap enough power, it might well be possible to desalinate water from the nearest ocean and pump it to wherever it's needed.

(Disclaimer: I haven't tried even back-of-the-envelope calculations about other costs of doing so, e.g., capital- and operating costs of pipelines, pumps, etc.)

Because I’m bored- Googling “cost to desalinate water” gives $2k per family of five, and googling “population of California” gives roughly a population of 40 million. 40mil/5 * 2k == 16 billion (if I’m counting zeroes right.)

So it’s in the ballpark of a percent of California’s total GDP (which is roughly 2 trillion, IIRC) for non-industrial uses. (But industry, including agriculture, is responsible for that GDP- how easily a “dry” Californian economy could support desalination can’t be inferred from these numbers!)

That's why "cheap enough" power.

Conceivably, using offshore wind turbines to power a desal plant could perhaps be cost-effective.

I mean, are you expecting power in the future to be a tenth as expensive as it is now? A hundredth? With “cheap enough” energy anything is possible, but I don’t see where we would get order of magnitude improvements there anytime soon.

I’m still hoping for nuclear fusion within my lifetime.