With ~2/3 (and growing) of Earth’s land area being arid, you’d expect there to be a lot more interest in reverse-desertification. It’s pretty well established by now that it’s almost entirely a labor allocation issue given that there’s success stories all over the world [1] (including in the US [2]) to just create earthworks that slow and divert water. Water seems to be the biggest single issue and so many deserts actually get enough of it during flash floods. With how much Elon is interested in terraforming Mars why not just start here?

[1] https://youtu.be/UAmai36XJDk?list=PLoU8oWWwU-06BGLH5y7AMbybv... [2] https://youtu.be/3JyEHdJS94s?list=PLoU8oWWwU-06BGLH5y7AMbybv...