The problem is growing the crops to feed these people, which is getting harder and harder every year due to the combination of Western donations out-competing local farms and especially the rise of desertification - in 2012, it was estimated that two thirds of the land area of the entirety of Africa that's still viable for farming would be gone by 2030 [1].

[1] https://www.un.org/africarenewal/web-features/desertificatio...