Environmental Classics, week 4: The Population Bomb

It is easy to criticize the inaccurate predictions of Paul Ehrlich’s The Population Bomb, from 25 years after the predicted collapse. Our population both national and global has grown, and agricultural production has kept pace or surpassed needs. Neither global famine nor global warfare has occurred, let alone reduced the population as predicted. And while AIDS has wreaked havoc, particularly in sub-Saharan Africa, it has not led to dramatic declines of population. So we are left with the questions of how and why his predictions erred.

First, our population has grown, though not to the levels he predicted. He discussed at length predictions estimating that populations would double in 35 years. Over those 35 years, our population grew more modestly, approximately 50% nationally and approximately 57% internationally. There is much speculation as to why his population growth estimates were inaccurate. He predicted a constant or increasing rate of growth based on historical data. He did not address the effects of improvements in the economic development of individuals and groups on birth rates. As nations developed economically and reduced infant mortality, the per child investment in education increased. As the investment per child has increased the number of children per family has decreased.

Additionally, Ehrlich failed to recognize the potential of the Green Revolution. He repeatedly criticizes it and suggests that those pinning their hopes on it are misguided. After experiences with pesticides such as those outlined in Silent Spring where technological advance provided only temporary productivity gains, and hurt productivity in the long run, it is easy to see where his cynicism regarding technocratic solutions might stem from. However, the Green Revolution dramatically improved agricultural productivity on limited quantities of land, resulting in less hunger worldwide, rather than more.

Another major theme in his writings is based in the externalities, particularly chemically related, coming from technologically advanced lifestyles. This includes many different types of pollution, such as lead in gasoline, pesticides, mercury, and the general consumption of fossil fuels. Here the record is more mixed. Some of these hazards have been regulated away, such as lead in gasoline. Others, such as our dependence on fossil fuel, have not improved at all. Given that he predicted no regulatory change in these factors (1 in 1000 odds or 1 in 100 with pressure from constituencies), this is better than his expectations, but still not entirely wrong.

It is important to realize that while the predictions made were inaccurate, there may still be validity to his fundamental argument. There are constraints on our resources. There is a limited amount of sunlight that hits our planet and only so much space on it. As such, it can only support a finite population. Our growth has slowed, and it may naturally follow an asymptotic progression, never quite reaching some theoretical maximum. But whether it is so is a question worthy of examination. We should not simply dismiss the question because of earlier, mistaken, alarmist projections.

note: the original included italics for titles which were lost in the cut & paste. If you consider this worthy of complaint, I suggest that you kiss my grits. 😉