I just ran across this video, and there's a LOT of info packed into it, covering not just the great green wall, but also CO2 from desertification, overgrazing, and rotational grazing. Overgrazing resulting in the release of carbon into the atmosphere--did you know there's more carbon stored in the soil than in the atmosphere? And when grasses are overgrazed, the plants and mircorganisms die, releasing their carbon into the atmosphere! There's:
250 million tons of C02 in animals
800 million tons of C02 in the atmosphere
2500 million tons of C02 in the soil
The great green wall is one of natural trees planted across Africa at the boarder of the desert. There's also one being planted in India. I love how this video doesn't just cover the pausing of desertification, but goes on to explain how rotational grazing, like Allan Savory's methods, can reverse desertification.
This is a lovely summary of things I've read and heard elsewhere. Certainly using herding a la Allan Savory is one effective method of "greening the desert", but I've read other versions where reforestation has been effective, so looking at food tree crops for humans and animals is another option in some places. What we really mustn't do is continue with the "status quo". Lot's of permaculture gurus talk about both storing water and storing carbon in the soil. There are lots of techniques in our toolboxes with different local applications. What's important is that we support others in doing so, and make an effort on our own part to do what we can.