If you spend enough time on the “educational” side of Youtube, you will come across short documentaries that talk about projects aimed at stopping desertification and climate change. One example is the green wall of trees, that multiple sub-saharan countries want to plant in order to stop the sahara from spreading. Another example are the plans to turn parts of the australian outback in to humid land by planting trees and building dams. My question is: Is there even enough fresh water to sustain all of those projects? Could you theoretically turn all deserts into humid forests?