BRIEFING: "Africa's population: The baby bonanza; Is Africa an exception to the rule that countries reap a 'demographic dividend' as they grow richer?" The Economist< 29 August 2009.

The familiar Africa: high birth rates and high death rates and a hugely young population that never seems to morph into that fat middle of laborers with few to support above (elderly) or below (kids). So Africa remains pre-1800, Malthusian, yes?

Yet there is another Africa, an Africa whose people are charting a course more similar to that of the rest of the world: one where they are living longer, having fewer children, and in which more of their children are surviving infancy. Cities are restraining population growth, just as they have in Asia and Latin America. Addis Ababa, Accra, Luanda, may be fetid in parts--shockingly so for those coming from richer countries--but they have low fertility. An emerging African middle class is taking out mortgages and moving into newly built flats--and two children is what they want.

Africa is experiencing huge change. Only about 100m in 1850, Africa is now 1B and will reach 2B by 2050 (or two Africans for every European). And yet the demographic reductions are real too: in 1990 the total fertility rate is over six. By 2030 it should be three. By 2050, when humanity tops off as a species, it'll be 2.5.

So Africa is not all that different when growth really comes.

But the key is to take advantage of that demographic divided (big middle, relatively small cohorts of kids and elderly) when it comes, because it does not last long. Indeed, China's will disappear more quickly than it arrived.

Why Malthus can still be right in Africa: birth rates are still too high (so more contraception please); agriculture vastly underperforms (all those small plots); and then there's climate change a' coming.

The second big problem is the lack of adults relative to kids. Estimates are that there are 50m orphans in Africa, and that the number will rise to 100m over time. Africa has the highest rate of child disablement in the world--up to 20%. This is why China will fade as the source of transnational adoptions and why the next wave will be all about Africa. Some day soon enough our family will join the burgeoning numbers of American families that include children from both China and Africa.

The third big problem is the continuing burden of disease (Sachs' focus).

Then there's the lack of government institutions, which just tells me that we--and China--will be in the nation-building business in Africa for decades.

So what makes Malthus finally wrong in Africa like he's been proven wrong everywhere else by now?

Globalization comes to town.