According to the United Nations, the world's population passed the 7 billion mark at the end of October. We can expect much tutting and shaking of heads over its prediction that we will be 10 billion by the end of the century, but almost nobody will have the temerity to point out that this is almost entirely an African problem.
The U.N. Population Fund's own numbers tell the story. Africa currently has one-seventh of the world's people: just over 1 billion. During the rest of the century, the U.N. agency predicts, this single continent will add an extra 2.6 billion people, more than tripling its population, while the rest of the world adds just half a billion.
If it weren't for the African population boom, the world's population would never exceed 7.5 billion. That is still probably twice as many people as the planet's resources could support comfortably for more than a couple of generations — but birthrates are falling to below replacement level in most places. If that were happening in Africa too, the global population could be headed back down well before 2100.