And a sprinkler system.
“Why not just plant a bunch of trees?
And a sprinkler system.”
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Use solar panels for energy to salinize water and pump it into desert-located tree farms. Start small, prove the concept, then start scaling up.
Lather, rinse, repeat in any suitable locations.
Alternatively, the water could be used to build up grasslands. Livestock eat the grass, and replenish the soil with their excrement. This has been proven to work.