Book Review: “The Bet” by Paul Sabin

I found this book over a book review by Bill Gates. Thanks to this tweet by Christopher N. Fox for the link.

The author is a history professor. This book is about recent United States history. It describes the debate about overpopulation and other environmental concerns in the decades between 1960 and 1990 in the United States, with a special emphasis on Paul Ehrlich and Julian Simon, both of whom I had not heard before.

Paul Ehrlich published a book called “The Population Bomb” in 1968. That book warns of the dangers of overpopulation and asks people to do something about this problem.

In contrast, Julian Simon used to think that overpopulation is a problem as well, but reconsidered. If Bentham’s idea of “the greatest happiness of the greatest number” as a goal of policy (utilitarianism) is correct, then having more people is better than having less.

So Julian Simon was one of the opponents of Ehrlich’s point of view. And the title of the book is a reference to a bet between Simon and Ehrlich, which has its own shiny Wikipedia entry here. This wager was on the price of five commodities over the next ten years. Simon took the optimistic view that those prices would go down, and Ehrlich the pessimistic view that as a consequence of overpopulation those prices would go up.

Simon won.

In a final chapter, Sabin describes how these discussions on overpopulation are related to present controversies over global warming. That’s where my interest lies right now.

And Sabin’s idea, which Bill Gates agrees with, is that the debate is too polarized now. He would like to see a more nuanced discussion of these questions.

Now for a couple of comments.

Obviously, Ehrlich was wrong on most of his short term predictions. That does not mean he will be wrong in the long term. But it is still quite true that his pessimism was overblown.

And it is also true that, if it is possible to sustain larger populations, the “greatest happiness of the greatest number” means larger populations are better than smaller ones. Population control may also conflict with valuing each individual life. That is most clearly understood with involuntary sterilizations or involuntary abortions (all abortions are of course involuntary from the point of view of the aborted person).

But what exactly can we learn from these discussions about global warming?

For one, all things equal, more people will need more energy and burn more fossil fuel than less people. China has listened to Ehrlich’s point of view and enacted a “one child policy“, which reduced China’s population by about 200 million people as compared to business as usual. That in turn means less CO2 from China at the same level of CO2 emissions per capita.

We also learn that it is difficult to exactly predict the future in the short term. And ten years is a short term when discussing these kind of issues.

While Ehrlich was wrong on the price of tin in 1990, he would have been right if he had bet on an increase on the price of fossil fuel from 1980 to 2010. Oil is substantially more expensive now than three decades ago, having gone from $30 to over $100 a barrel (after dropping to $20 in 1990).

And that is a good thing. All things equal, oil at $100 a barrel will lead to a faster transition from stinking gasoline cars to electrical vehicles than oil at $2 a barrel (the price in 1972). If anything, I hope that Jeremy Leggett is right with his peak oil predictions and the price of oil explodes like the price of bitcoins this year.

Published by kflenz

Professor at Aoyama Gakuin University, Tokyo. Author of Lenz Blog (since 2003,

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