[thaumasiotes]

> Though the southwest is a great place to farm if you have the water to leverage the sun and the relative dearth of pests. Given the economic potential of a huge fraction of the country, I'd wager that getting water there will be worthwhile within my lifetime.

The reason for the dearth of pests is that it's a desert. If you change that, the pests will arrive just like everything else does.

[zbrozek]

It's true, but that'll take quite a long time and the advantage is unlikely to evaporate completely even if it erodes. And there's probably no amount of water use that humans can realistically achieve in that same time period which will take away the sunlight.