The coming depopulation

My brother and his wife were recently in town for a surprise visit (my birthday). At one point, over lunch, the conversation turned to population growth and the woes of the world. I pointed out that all was not lost, since the Earth’s population was going to peak in this century and shrink for a long time to come thereafter.

I was challenged on this point and asked to provide a little support for my assertion.

The most forceful description of this situation that I’ve come across is Phillip Longman‘s talk at the Long Now Foundation entitled The Depopulation Problem. He’s written the entire speech out as a PDF file. It’s worth reading. It’s got some startling facts in it. It’s reasonably well known, for example, that industrialized countries like Japan and Italy are producing children at below the replacement rate, which is to say, they’re shrinking. Russia is shrinking at the incredible rate of three quarters of a million people every year. That’s nontrivial shrinkage.

People who are aware of this phenomenon in rich countries still generally believe that it’s more than made up for by high fertility in poor countries. But this isn’t true. Here’s what Longman says.

In no industrialized nation today is fertility high enough to prevent declining population. In countries as diverse as Italy, Japan, Spain and Korea, fertility rates are so low that population loss on the order of 30 to 50 percent per generation are in the works… Yet what is even more surprising is the rapid decline in fertility now seen in the developing world. The phenomenon of sub-replacement fertility has by now spread to ever corner and continent of the globe.

In short, Longman actually paints a gloomy picture of what a depopulating world may look like. That part is controversial, but the basic demographic premise is not: we’re done doubling the world’s population.

As further evidence of this point, look at the organization called Zero Population Growth, an organization that was founded by Mr. Population Bomb himself, Paul Ehrlich. That organization is not even called Zero Population Growth anymore. It’s called Population Connection. They still have plenty of good work to do with overcrowding and environmental issues, but even they agree that the population curve is flattening this century.

For all the wretched things going on in the world, that’s a pleasant thought.