- How has historical human population growth compared with the "natural" (or exponential) growth model for biological populations? What does this imply about percentage growth rates?
- Historically, the population growth rate has been proportional to what power of the population? Recall that the assumption underlying the coalition model was that r would turn out to be "small." Was it small?
- The title of the 1960 paper by von Foerster, Mora, and Amiot was "Doomsday: Friday, 13 November A. D. 2026." How close was your prediction of Doomsday to theirs? (Keep in mind that you were working with more "reliable" data before 1960, plus later data not accessible to them, so there was no reason for your conclusion to be the same.)
- What would be the social and political implications -- as predicted by the coalition model -- of human beings continuing to behave indefinitely as they always have in the past?
- Recent evidence suggests that human behavior might in fact be changing. According to the
U. S. Census Bureau, in what year did the average percentage growth rate peak? In what year did the annual growth in population peak?
- Given the predictions of population growth through your lifetime, how serious a problem do you see for your generation in coping with the pressures of increased population?
While the Doomsday authors wrote with their tongues firmly in their respective cheeks, it's rather remarkable that they also constructed the most accurate predictor of real population growth for almost two generations. Historical data is a good predictor when the behavior that produced it does not change. Only now are we beginning to see any substantial change in this behavior on a global scale.
Here are some additional links for further study:
- Visit our sister site at Montana State for a completely different take on the Census Bureau data.
- Visit the Population Reference Bureau for much more information about human population growth.
Visit Zero Population Growth for information about the problems of overpopulation.
Editor's note, 12/04: ZPG has changed its name to Population Connection. The link to ZPG now goes to a transitional page that explains the name change and links to the new site.
David A. Smith and Lawrence C. Moore, "World Population Growth - Summary," Loci (December 2004)
Journal of Online Mathematics and its Applications