Africa may account for half of mankind by 2100. It is the only continent which still has very robust TFRs.
As of now, the population growth is already creating some very powerful migration pressures. Most of them stay on the African continent, but even the few per cent that reach Europe are enough to turn European politics full tilt to the far right. It doesn't help that Sahel, the most fertile part of Africa, is also one of the most arid - and Islamic at the same time, so a clash of values with secular liberal European societies is all but guaranteed.
The new Cold War will have a significant migration dimension.