Posner and Becker on 10 Billion People

Posner‘s a nervous optimist:

But suppose world population will reach 10.1 billion by the end of this century. Would that be a good or a bad thing? Arguably a good thing, on several grounds. One is that it would enable greater specialization, which reduces costs. Second is that it would increase the returns to innovation by increasing the size of markets, though an offset is that innovation can produce immensely destructive as well as constructive technology. Third, the more people there will be, the more high-IQ people there will be, and hence the faster the growth of knowledge will be; though a possible offset is that the more evil geniuses and other monsters there also will be; persons of great potential for evil, such as Hitler, Stalin, and Mao, presumably are rare…*

The downside of population growth is the pressure it places on the environment and natural resources, especially the former, since the price system provides efficient rationing of resource use… Continued population growth could combine with an acceleration of global warming to precipitate a global catastrophe (perhaps a catastrophic water shortage) within the next few decades, but 89 years from now the march of technology may enable such problems to be solved. Think of the technological advances of the last 89 years (that is, since 1922), and imagine a comparable rate of technological advance applied to the current level of technology, which is so much higher than that of 1922. 

But the beneficent effects of population growth, like the estimates of that growth, are highly uncertain. The risk averse among us might prefer a lower rate of population growth in order to reduce the downside risks of that growth, even though the upside potential would be reduced as well.

Becker‘s a calm optimist:

The substantial world growth in per capita incomes during the past 150 years has been associated with growing world populations. I believe that declining populations are bad for long run economic welfare…

Given the sharp rise in food prices during this first decade of the 21^st century, it would appear difficult to feed adequately a much larger and richer world population. Yet, unlike say the production of copper, no natural limits sharply curtail the amounts of food that can be produced. Food output will expand with a growth in the amount of land devoted to food production-currently agriculture takes a small fraction of the world’s arable land. Also, the world can invest much more in fertilizers and in improving food technology, so that greater output can be squeezed out of each acre used to grow corn, wheat, soy, dairy, meats, and other foods.

Greater demand for water due to larger populations and greater wealth would make clean water scarcer… [But] With sensible prices, the available water should be sufficient to satisfy all essential water needs of a much larger world population.

[…]

A larger population combined with growing per capita incomes would increase global warming and worldwide pollution… [T]he world should be prepared to meet various worst-case climate scenarios. This would require the development of mitigation techniques that can be rather quickly ramped up in case global warming turns out to be a severe problem… Such technologies are certainly achievable by the end of the century with substantial private and public investments in developing new methods to capture and store various harmful gases emitted by fossil fuels.

If world population grew to 10 billion by the end of the century — an unlikely outcome — that would present considerable challenges. However, greater population would add real benefits as well, and I am inclined toward the view that the benefits will exceed the harm.

Both more reasonable by far than Bad Religion’s “10 in 2010,” but the song’s too singable to hate.

* I make the same point at greater length here.

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