All across Africa, there are infestations of Aquatic weeds. These are the real driving force in desertification. They quadruple evapotranspiration and clog waterways of all sorts. In particular, the Typha Australis infestation of the Lake Chad basin is the dessication machine drying out the Sahel. Typha is one of the most productive plants in the world, and one of the hardiest. Its clearance from Lake Chad and it surroundings will be a never ending process, but one that can be run at a profit in food and fuel and biochar for terra preta. The topsoil that the cattails have produced can also be used to restore desert land. Typha, and the other weeds are great CO2 sequesterers, too. but for every molecule of CO2 they absorb, they absorb one of H2O (making carbohydrate) and transpire many more. The plant has a habit of collecting pollutants, so not just any can be eaten. What isn't fit for human consumption can be brewed into ethanol, or pyrolized into charcoal for fuel and biochar.
