Forgive me for not looking up the full quote. But I strongly object to your suggestion that Africans live in the deserts. Of course there are human population where drinking water is an issue, you mentioned a few places in the US and there are similar locations for cities in Africa. But the idea that Africans live in deserts comes from images from farmlands during severe drought periods or refugee camps from people who have to flee into the barren deserts to avoid racial, religious or political persecution. Somalia, Ethiopia and Kenya is some of the most fertile lands on the planet and some of the greatest food exporters in the world, not unlike the US Midwest or California. And similar to these areas there are occasional droughts when the food harvests fails which can create terrifying images of people living in what looks like a desert.