That's okay, because the population density of Africa is very low (it's comparable to that of the Americas, much less than Europe/Asia)[1], it's currently only 15% of the world's population[2], and Africa is an enormous continent[3] the fact of which the Mercator projection distorts[4].
You're right there, however I'm afraid the issue won't be density but a much different issue: Unemployment. [1] Reason this could be a worldwide issue is the opportunity cost. Can we afford not to have a billion or more minds on board to solve some of the worlds most pressing problems? China is trying its best to industrialize and capitalize on the growth. But many are claiming their tactics are almost neocolonialist. [2]