I read William Langewiesche's travelogue where he crossed the Sahara overland after being a pilot who flew over for a few years. He said that the locals are rather fatalistic about living in such a massive and unforgiving place (people frequently die there); they say that when god decides it's your time, then it's your time. Langewiesche added that if you don't believe in god, then you can replace that with "The Sahara" and it still works quite well.
I cannot imagine that there is much humans can do to hold back the desert. I'm quite sure that the only thing that would matter, a rapid drawdown of carbon emissions, is not possible at this point. I know it sucks, sorry.
It'll get harder to maintain that pace as heat increases too. There'll be fewer and fewer hours that people can work outside. Rising temperatures will bring more heat-related illnesses and injuries. Considering the amount of ground they want to cover bringing in machinery to speed things up does sound like a good idea.
Of course as the village population grows you send the "young men" out to the edge and have them dig a few more half-moons at a rate of one/day. However they are building next to previous green areas which are already lowering the local temperature, and if sometimes it takes 2 days to build one - who cares, there is no hurry.
>Of course as the village population grows you send the "young men" out to the edge and have them dig a few more half-moons at a rate of one/day.
Uh huh - because that's what young men want to do, dig ditches for no wage or subsistence-level wage.
What's going to happen is those who can, will simply leave.
> because that's what young men want to do, dig ditches for no wage or subsistence-level wage.
It is an investment - see that bare desert over there, work off energy by digging it. Then when they "grow up" they discover that bare desert is their land to farm and their time was really a good investment in their future and gives them a good remainder of their life, and their kids a chance for an even better life.
Those who can will leave (unless they love farming), but today the majority don't have any better place to go. Stay in the village at the edge of the desert and dig in these green places means a better life than going to the city and trying to find a jobs (remember these people don't have skills in demand in the city either, other than their ability to dig ditches in the city, at least in the desert they can take ownership of the land they make better and have a farm.)
Ideally in 50 years Africa will improve conditions and industrial scale farming will take over, sending 98% of the people (there decedents) to a city where they work not as basic labor but as skilled labor (doctors, engineers...). However they are not in this position now and this looks like a step on the path to getting there.
What was shown in the video looks like a "mickey mouse" operation, akin to a local tree planting effort to combat climate change. For this to make any difference you can't have people digging "half-moons" at a rate of 1 person/1 half-moon/1 day - that does not scale in any meaningful way. You need to do this kind of project at an industrial scale, with large amounts of heavy machinery and thousands of skilled professional workers - especially since they are discussing creating a "Green Wall" across thousands of kilometers at a width of hundreds of kilometers.