Too many people? (a reply)

It’s an enticing argument, but it overlooks the great unknown in the current situation. As we increase the human population, we increase the pressure on the complicated biological system that sustains life on our home planet. Our knowledge of that system is still limited. We can’t assume we know all the traps that could destroy us.

There is a real possibility, for example, that global warming could trigger a catastrophic release of the methane stored in peat bogs.

The decrease in biodiversity presents another threat. We are destroying big chunks of the system without bothering to find out what they do or how they fit into the network.

A little caution seems reasonable. The exponential, unlimited growth of the human population may be possible but we would be safer if we slowed it down, or even reversed it.

Increase brainpower

Fortunately, we don’t have to increase the population to increase the number of educated minds. We can increase the available brainpower by improving living standards. We’ve done that for more than two centuries now, and it’s the main reason we have more people like Ajay Bhatt, the entrepreneur Dan refers to in his second piece.

A simple increase in the number of brains doesn’t do you any good if the owners of those brains all work in the fields growing rice. One educated brain is worth several dozen illiterate subsistence farmers.

The rise in living standards, in addition, tends to reduce population growth. As I noted two years ago in my comments on Sylvia Nasar’s book Grand Pursuit, birth rates drop as living standards rise. (Click here.)

The birth rates in the richest countries have been dropping for decades. Right now, they’re hovering right around the replacement rate.

The Malthusians’ error

Birth rates drop in expanding economies because higher living standards surround people with incentives to limit their families. If you put off marriage until you’re in your late 20s, you can go to college and establish yourself in a lucrative career. If you have two children instead of four, you can send your own kids to college and still enjoy a few perks like vacation trips and wide screen TVs.

In the 1950s, modern Malthusians assumed the world population would continue to grow by three percentage points per year, doubling about every 25 years. If the population continued to grow at that rate, we would hit 28 billion by 2050.

The Cassandras of overpopulation erred because they engaged in a simple straight-line extrapolation and assumed the 3% trend would continue indefinitely. You get a different result if you assume living standards will continue to rise and the global birth rate will continue to fall. If that trend continues, most current forecasts predict that the world population will level off around 10 billion sometime before the end of this century and will decline after that.

The rise in living standards may not continue, of course. In that case, the global population will probably be reduced by famine, disease and wars fought over resources. Either way, I don’t think we’re going to get much beyond ten billion.

My fearless forecast

Personally, I think the rise in living standards will continue. You can even see signs of progress in sub-Saharan African, which looked like a basket case for most of the last 50 years.

I’m even willing to make a prediction. Sometime in the next 30 years, some of the African nations will achieve the kind of economic growth rates that Japan and Korea achieved 30 years ago, and pundits in the U.S. will fret that America can’t compete, jobs are being lost to cheap African labor, and we can only survive if we reform our entire society and adapt the secret techniques of the Africans. And no one will admit that Americans are living better than they lived in 2013.

To read a response by Dan Rottenberg, click here.