Why falling birth rates will be a bigger problem than overpopulation

Think of global population problems and you might think of the growing number of people in the world – currently about 8 billion – and our collective toll on the planet. But due to people having fewer children as countries become more prosperous, the real demographic problem may turn out to be falling populations.

Projecting from current trends, demographers have now predicted that, within about 25 years, three-quarters of countries will have birth rates that are too…