A global baby bust is slowing growth in every major economy, from China and Japan to Germany and the US. But the flip side of this story goes untold: even economies that could still get a big boost from population growth are failing to do so.  

The biggest problem for global growth is Africa, now home to 1.5bn people. One in three of those entering the workforce will live on the continent by the 2030s. For the world economy to grow faster as a whole, Africa would need to find a way to employ these workers productively and capitalise on its demographic dividend. But for most African countries, that’s not happening.  

My research shows that a rate of growth in the working-age population of at least 2 per cent is a necessary condition for “miracle” economic growth, implying a sustained pace of at least 6 per cent. As of 2000, 110 countries had a working-age population growth that fast, nearly half in Africa. Now there are just 58, with 41 or more than two-thirds in Africa.