'Depopulation would mean fewer people contributing to advancement of knowledge'

Trends show that in a few decades, global population will begin to shrink. Once depopulation starts, no one knows how to stop it in a sustained way, write DEAN SPEARS and MICHAEL GERUSO, associate professors of economics, University of Texas at Austin, US, in their recent book, After the Spike. The authors, who are also economic demographers, argue that population decline will be detrimental to global progress and that a smaller population would not necessarily be better for the environment. In an interview with ADITYA MISRA, they say that the time to talk about depopulation is now because the search for a solution could take decades. Excerpts:

- DEAN SPEARS and MICHAEL GERUSO

What are the consequences of depopulation—the worst-case scenarios—that the world needs to worry about or be prepared for?

A future with fewer people will be a future with slower improvements in some areas and stalled progress in others. Over the long run, larger populations—not only national populations, but the global population—make each of us better off. That’s one argument (though not the only one) that we make in detail in our book After the Spike: Population, Progress, and the Case for People.

Living in a big world with many other people makes each of us better off. As we wrote recently in The New York Times: “Whenever people need and want things, they make it more likely that you will get what you need and want. That's true if what you want is good public transportation (because a network of trains and buses can’t operate without enough riders), or green energy infrastructure built on the work of scientists and engineers across generations and borders, or a vaccine for a novel virus, or a cure for a rare disease that only the niche medical specialisation of a big world could produce.”

The past two centuries were a revolution in better living standards as our population climbed. We should not be complacent about retreating to a smaller world.

You write that when depopulation happens, it would not spontaneously halt at a smaller point. Why would it not? Would countries not take steps to check depopulation if it becomes a problem? Why should it be a concern now?

There is no reason to expect an automatic reversal, nor is any playbook sure to halt global depopulation once it starts.