Africa you look at the numbers and you think, "That's impossible."
Uganda had about 7 million people at independence in 1962, and in only 45 years it has grown to 30 million. By 2050, just over four more decades from now, there will be 130 million Ugandans, and it will be the 12th-biggest country in the world, with more people than Russia or Japan.
Its population will have increased 18-fold in less than 90 years.
Many think population growth is no longer a problem, and everybody somehow knows that it is politically incorrect to talk about it. Back in 1968, when Paul Ehrlich terrified everybody with his book The Population Bomb, it was seen as the gravest long-term threat, but now it scarcely gets a mention even in discussions of climate change as if the number of people producing and consuming on this planet had no relevance to pressures on the environment.
True, the population explosion has gone away in large parts of the world, in the sense that most developed countries now have birth rates well below replacement level (2.1 children per woman), and that the global average, including Asia and South America, is now down to 2.3 children. But there remains the problem of what you might call "inertial growth."
My own mother had five children, which was not seen as at all unusual at the time in Newfoundland. The next generation of our family, by contrast, dropped to 2.0: we five brothers and sisters and our five spouses have a total of just 10 children. But that doesn't mean that our boom stopped.
If we had just spawned and died, it would have, but we insisted in living on after our children were born. In fact, we're all still here, although the first grandchildren are already starting to appear so where there were once 10 of us, there are now 23. It takes two full generations at replacement level before the population finally stabilizes.
That accounts for about half the anticipated population growth in the next 40 years, which will raise the number of people on the planet from 6.5 billion to about 9 billion.
But the other half of the growth comes mainly from Africa. This may explain why it became politically incorrect to talk about population growth. Nine out of the 10 countries with the highest birth rates are African (the other is Afghanistan), and it seemed uncomfortably like pointing the finger at the victim. Yet runaway population growth is a big factor in making so many Africans victims, and it doesn't help to stay silent about it.
Sometimes the steadily worsening ratio of people to resources just causes deepening poverty, as in the case of Nigeria, whose population by 2050 will reach 300 million. Often, however, the growing pressure of people on the land leads indirectly to catastrophic wars: Sierra Leone, Liberia, Uganda, Somalia, Congo, Angola and Burundi have all been devastated by chronic, many-sided civil wars, and all seven appear in the top-10 birth list.
Rwanda, Ethiopia and Mozambique, which have suffered similar ordeals, are just out of the top 10. Africa, only 8 per cent of the world's population in the 1960s, will contain almost a quarter of the world's (much larger) population in 2050.
This will have remarkably little impact on climate change, since most Africans have a small environmental footprint. They will be poor mainly because their populations are growing three times faster than the average, and you can't say that this is nobody's fault. It is a failure of government.
The reason birth rates dropped in the rest of the world was that cheap, effective contraception became freely available. Once women realized they didn't have to have many children in order that at least some would survive, they took advantage of contraception with little urging from above.
Uganda's birth rate is seven children per woman. Uganda's president, Yoweri Museveni, believes his country is under-populated. He has done many good things, but this blind spot could undo them all. He is far from alone.
Gwynne Dyer is a London-based independent journalist whose articles are published in 45 countries. He appears in NOW weekly.