Who would have won the Simon-Ehrlich bet over different decades

In 1980, the biologist Paul Ehrlich agreed to a bet with the economist Julian Simon on how the prices of five materials would change over the next decade.

Paul Ehrlich had a clear expectation. He thought population growth would quickly deplete the planet’s resources. As a consequence, he expected that the cost of resources — including minerals — would rise steeply as they became more scarce.

This claim got the attention of Julian Simon, who expected the opposite. Simon thought that human innovation and ingenuity would overcome resource shortages, and the price of resources would, therefore, not rise but fall. In the pages of the Social Science Quarterly, he challenged Ehrlich to put money on the line.

Simon offered Ehrlich the chance to choose any resource he wanted for the bet. Ehrlich chose five: chromium, copper, nickel, tin, and tungsten. The two bet $1,000 — $200 on each metal — on whether inflation-adjusted prices of these resources in September 1990 would be higher or lower than they were in September 1980. If prices had increased, Ehrlich would win. If they had fallen, victory would go to Simon.

The chart below shows us the change in the price of the five materials in 1990 compared to 1980. Note that this is based on the average prices that year, not necessarily the price in September of each year. But the final results of the bet are the same, regardless of whether you take annual average prices or those specifically in September.

All five had become cheaper, so Simon won the bet (and Ehrlich did mail him the check).

The cost of tungsten and tin was more than 60% lower. Copper was around 20% cheaper. Nickel and chromium were only slightly cheaper than a decade before. None of them had increased in price, contrary to Ehrlich’s prediction.

See the article for more details on the bet.