I was astonished by the Great Green Wall Initiative in Africa. The plan is to create a continent-spanning wall of vegetation to prevent the Sahara Desert from expanding southward. It is nothing if not ambitious.
Apparently, the first phase is to create huge number of these tiny plots shaped in a special way to prevent rainwater from running off and planting drought-hardy native species in them, some of which can be harvested as a food source. Eventually, once the soil has recovered sufficiently, they can plant trees.
The initiative is high-tech in the sense of applying state-of-the-art knowledge on land management but low-tech in the sense that it will involve a whole lot of manual labour with simple implements.
But the scope of it is insane with 22 countries having signed on. It gives me hope that collective action in the face of climate change is possible anywhere in the world.