Paul Ehrlich on Overpopulation

by Bill Chameides | February 3rd, 2009
posted by Erica Rowell (Editor)

Permalink | 3 comments

Paul Ehrlich, professor at Stanford University and fellow member of the National Academy of Sciences’ Section 63 on Environmental Sciences and Ecology, spoke at Duke last night. His message on overpopulation has evolved to include consumption.

In 1968, Paul Ehrlich’s The Population Bomb predicted society’s imminent doom. Yesterday, speaking at Duke, he painted a picture for humanity that is less doomed but still quite sobering.

Except for maybe a Nobel, Paul Ehrlich, the Bing Professor of Population Studies at Stanford University, has won just about every award possible, from the MacArthur “Genius” Award to the Volvo Environmental Prize.* He is a tall stately man with a deep booming voice and a droll sense of humor.

In his extemporaneous speech last night, part of this year’s Provost’s Lecture Series at Duke, he liberally sprinkled in anecdotes and non sequiturs. My favorite was his reference to the work of Joshua Lederberg and E. L. Tatum, the team who “discovered” sex in bacteria. “The bacteria, said Ehrlich, “were ever so thankful.”

Ehrlich’s Prognostications 

Ehrlich’s The Population Bomb made him a household name back in the late 1960s and early 1970s. In it, he characterized the rise in human populations as a runaway train that would lead to major catastrophes within a decade or two, as humanity’s needs outstripped available resources. Clearly Ehrlich’s doomsday predictions did not come to pass (at least not yet), and he has been roundly criticized by some (see here and here).

Probably his best-known debacle was his infamous wager with Julian Simon, the University of Maryland business professor who held opposing ideas on population. In 1980 Ehrlich (along with other colleagues, including President Obama’s soon-to-be science adviser John Holdren) bet Simon that the price of five commodities would go up over the ensuing 10 years. Ehrlich lost, and reportedly ended up having to pay Simon $567.07. While most have interpreted the bet’s outcome as a repudiation of Ehrlich’s thesis, Ehrlich claims otherwise.

The Missing Factors of Technology, Industrialization, and Educated Women

It is hard to debate the fact that, in his 1968 book, Ehrlich underestimated the ability of technological advances to keep ahead or even abreast of the burgeoning demand for resources driven by population growth and increasing affluence. I think he also didn’t adequately account for the fact that populations tend to stabilize as societies become more urban and industrial and women become more educated – this is the so-called demographic shift. In fact demographers now predict that because of this demographic shift, the world’s human population will stabilize sometime this century at perhaps 9 billion (see here and here). That’s a whole lot of people, no question, but at least it appears to be bounded.

But while Ehrlich may have gotten his timing wrong, his fundamental message that as a species we are on a collision course with the Earth’s limited ability to support us may be correct. Indeed Ehrlich’s talk at Duke yesterday evening, while perhaps somewhat more subdued than his speeches from earlier decades, was an impassioned plea to consider the course we are on.

A Look at Population in Terms of Numbers and Consumption

A subtle but important evolution in his framing of the question of population is the emphasis on consumption as well as numbers. By Ehrlich’s reckoning, America is the world’s most “overpoplulated” country. While only the third most populous, we use far more resources than any other country, and thus, in terms of impact, we have the largest footprint.

In contrast to years ago when his main issue was population control, last night Ehrlich cited four things that cause him the most worry about the future:

  1. Climate change: Ehrlich believes that the most serious consequence of global warming will be an undermining of agriculture and the collapse of our food supply;
  2. Earth toxicification: The hundreds of thousands of new chemicals we have added to the environment (e.g., endocrine disruptors) may be a time bomb waiting to decimate us;
  3. Emerging diseases: Overcrowding of people and animals is a dangerous recipe for a new pandemic;
  4. Nuclear weapons: Despite the end of the Cold War some 20 years ago, nuclear weapons remain “on hair trigger” alert in the both the United States and the independent states of the former Soviet Union; an accidental nuclear exchange could lead to “nuclear winter” and a collapse of the food supply.

Ehrlich, who spoke for a little over an hour, held our attention throughout. A small group of us then went to dinner to muse about science and politics. We got him to relate wonderful stories about his various world travels including his experience as a 19 year-old college student working with the Inuit. People may still call him a doomsayer, but he’s not the fire-and-brimstone type. He’s gregarious and easy going with a twinkle in his eye and a smile on his face.

While Ehrlich may have taken some lumps in sounding the alarm about humanity and the environment, he remains convinced of his message. And when all is said and done, I find it hard to dismiss his thesis that our society is in danger of outstripping the Earth’s ability to support it. Even at “just” 6.7 billion people, we are unable to find adequate resources for all – witness the close to a billion or so malnourished among us. Now imagine a world of 9 plus billion people. Maybe the Ehrlichs of the world have something to tell us.

*In fact a different Paul Ehrlich won the 1908 Nobel Prize in Physiology.

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  1. Pete Murphy
    Feb 5, 2009

    Ehrlich advocates both reducing our population and our per capita consumption to relieve the strain on the ecosystem. But he forgets that reducing consumption is a prescription for rising unemployment and poverty. The only way to relieve the strain on the ecosystem while maintaining a high standard of living is to reduce the population even further, in the U.S. and even more dramatically in the much more densely populated regions of the world like Asia and Europe. The single greatest obstacle to progress on this issue is economists who, following the black eye the field of economics received from the seeming failure of Malthus’ theory, steadfastly refuse to ever again give consideration to the consequences of population growth. They now shrug it off and proclaim that man is ingenious enough to overcome any obstacle to further growth. Even worse, they claim that population growth is an essential element of economic development and that it’s impossible to have a healthy economy without it. If they would just get over this irrational fear of the subject, they might see that there is actually an economic price to be paid for overpopulation – that beyond a certain point, a rising population density begins to erode per capita consumption, fueling a rise in unemployment and poverty. While the macroeconomy may continue to grow, it’s a cancerous growth that erodes the the economy at the microeconomic level – the finances of individuals. Pete Murphy Author, “Five Short Blasts”

    • Bill Chameides
      Feb 6, 2009

      Dr. Chameides responds – Pete: Thank you for your thoughtful post – you’ve made a lot of good points, but consider the following: 1. I do not agree that reducing consumption necessarily leads to unemployment and poverty. Indeed one might argue that our consumer-driven economy was responsible, at least in part, for our current economic woes. And for all the consumerism that has characterized our economic behavior in recent decades, it did not alleviate unemployment and poverty. 2. There are ways of decreasing consumerism that would have major benefits for the poor: for example, consuming less meat. 3. Whether people are comfortable with zero population growth or not, demographers tell us it is inevitable as the world transitions to a largely urban, technological society. 4. Finally, population growth has an inertia of its own. Most demographers will tell you that it is essentially impossible to prevent the global population from exceeding 8 billion regardless of the population growth measures we take now. The world simply cannot support a world of 8 billion consuming resources like we do in the developed economies. For our own survival we must rein in consumption, and if we don’t do it, it will be forced upon us in ways that will be far less palatable.

      • amanda
        Feb 26, 2009

        hi wats up i like yr story

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