[Alneyan]

I would believe AIDS to be particularly devastating because it is easily transmitted to offsprings, which will carry the virus themselves, and so on. That is closer to biology though, and not exactly my field of study, so I should keep quiet here.

Add to that the usual problems (wars, corruption, not so nice leaders, malnutrition, shortage of water...), and you could reach a very bleak projection. Of course, it would not be possible to know whether these problems will be so worse as to destroy Africa's population, or if the very high number of children per woman will be enough, or... The growth rate was still positive Last year (2.3%), and you would probably need dramatic events in the future to bring the 840 million inhabitants of Africa down to 100 millions in fifty years (not the kind of things I would like to see myself).