Demographics

From population bomb to development opportunity: New perspectives on demographic change

A generation ago, the World Development Report 1984 focused on development challenges posed by demographic change, reflecting the world’s concerns about run-away population growth. Global population growth rates had peaked at more than two percent a year in the late 1960s and the incredibly high average fertility rates of that decade – almost six births per woman – provided the momentum to keep population growth rates elevated for several decades (Fig 1). Indeed, the population and development zeitgeist spawned works such as Ehrlich’s 1968 book “Population Bomb,” which painted apocalyptic images of a world struggling to sustain itself under the sheer weight of its people. The policy discussion of the WDR 1984 reflected these concerns, focusing on how to feed the growing populations in the poorest and highest fertility countries, while also presenting a case for policies that would reduce fertility.

Ninety years ago, in his A Tract on Monetary Reform Keynes famously wrote “In the long run we are all dead”. That observation recently stirred a lot of debate for all the wrong reasons, after Niall Ferguson obnoxiously claimed that Keynes did not care about the future because he was childless. Whether Keynes cared about the long-term future or not (and whether he had children or not) is completely irrelevant in this context, as many (e.g. Brad DeLong and Paul Krugman) have pointed out.

The actual context in which Keynes wrote this observation was a discussion about the quantity theory of money, which states that doubling the supply of money will only double the prices, but will have no consequences for other parts of the economy. This is the classical dichotomy between real and nominal variables. Keynes argued: “Now in the long run this is probably true”. But “In the long run we are all dead. Economists set themselves too easy, too useless a task if in tempestuous seasons they can only tell us that when the storm is long past the ocean is flat again.” So, Keynes’ point was obviously not that the future doesn’t matter. His point was that simple theories that might describe long-term relationships are just not good enough to deal with current issues. In the short run, changes in money supply can have all kinds of important consequences beyond the price levels. Economists will have to make their hands dirty and delve into the complicated dynamics of the here and now.