Coming May 3rd: Discussion with Russell Hopfenberg

Special Event

On Thursday, May 3rd, we will have Dr. Russell Hopfenberg here to discuss his work on the links between food supply, carrying capacity, and population growth. In two peer reviewed journal articles, one coauthored by David Pimentel, Russ has analyzed and investigated the relationship between between human population and food supply. His conclusion is that global food supply is the variable which best accounts for human carrying capacity, and that human population will continue to grow as long as food supply increases.

The first of those articles is available here, the second here. (update 10/04/07, the latter became unavailable online, except for the abstract. I’ll try to provide a PDF in the future. As an alternative, see the slideshow here.)

An important precursor to Hopfenberg and Pimentel’s work has been the writing of Daniel Quinn, author of Ishmael, who said, “The program of totalitarian agriculture is to increase food production in order to outpace population growth that is fueled by the very increases it produces, and this is what makes it unsustainable.”

The provocative conclusion is that if we want to stabilize population growth, then “halting increases in food production will halt the increases in population by means of a reduced birth rate.”

For a bit more background here are two Wikipedia articles which touch directly on this topic:

(I can’t vouch for the quality of those Wiki articles. I notice both contain some important unsourced statements. As far as I can tell, though, they offer a reasonable summary.)

Questions and comments for Dr. Hopfenberg

Prior to May 3rd, the comment section beneath this post will serve as the place for any questions or comments anyone might have of Russ. A number of prior questions and comments can be found under an earlier post, beginning here. Russ will have the chance to review the questions and comments in both places.

On May 3rd, I will have a new post in place at the top of the front page under which Russ will post some comments on his research, likely responding to some of the questions and comments submitted up to that point. Then, anyone can post additional comments/questions in the same place. Russ will return, probably a few days later, to follow up, again under the same post, in response to those comments/questions.

I will of course post updates if any details change.

I appreciate Russ’s taking time out to participate here. This is a rare opportunity to discuss a well known, somewhat controversial piece of research directly with its author. The implications of the work in question could potentially be profound. I hope everyone interested in questions of carrying capacity and population, and how human population growth might be stabilized will take full advantage by reading and considering some of the links above and participating in the discussion. Thanks!

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26 responses to “Coming May 3rd: Discussion with Russell Hopfenberg

  1. I have to say this sounds all very scary, but I will tell you that in my bioethics class we had a chat about a few things. This was awhile ago I have since graduated (philosophy so don’t laugh at my ignorance in regards to science, not my fault…lol..)

    In a small rural village in Mexico they traditionally had many children, but because of the limited in advance in medicine most of the children would die. This was their culture. When their children would die the villagers would have beautiful funerals. It was sad, but beautiful and because of this there would be enough food for everyone in the village.

    Years pass…the US steps in and they are horrified at the dying children. The funerals make everyone sad so the US decides to “help” the people in this small rural village, but they still have the same amount of children. Of course you can deduct what happened. There are too many people and not enough food. And so what do we in the US do again, we “fix it” by giving them food…

    I don’t know…that story always seemed very cruel to me. If people had just left things alone, but how can you leave things alone. I think in America there is this thing that we feel we have to help everyone to be just like us, but we do it in this very half assed way.

    It always seems to make things worse.

    We always think we’re being nicer by saving people from death regardless of the quality of life. I would never want to play God with people, but who are we to play God by helping them live in misery.

    I guess the thing is there are some people who aren’t altruistic in their motives in wanting to do things. We just have to make sure that those are not the people in charge. That it doesn’t become one group being targeted because they are the “wrong” ethnicity or religion or country or everyone else finds them annoying…

    This might sound silly, but I always felt that Star Trek would probably be a very good model in deciding these kinds of things. A body of nations where everyone got a fair say, no matter how small the country, like the US Senate. I know the UN is suppose to be that, but it seems like it is very Western Europe/ US centered, which since in the US maybe I shouldn’t care, but I do. Hey I think in this final paragraph I’ve been a hypocrite by trying to use American values and pop culture to fix a major world issue…


  2. Lo,

    Your story of the Mexican village sounds like a lesson in unforeseen consequences. I think Russ Hopfenberg would probably say our efforts to feed the global population have had the unforeseen consequence of causing the population to keep growing to the point that we’ve overshot the ecosystem’s limits and could potentially face problems much worse than we would have had we not tried to make food supplies keep up with population.

    I think, though, (and I’m a little unclear on this) that he’d also say that if we stopped increasing the food supply it wouldn’t actually cause any (many?) added deaths due to starvation. That’s what Steve mentioned, anyway, in one of the links I provided. He argued that we don’t rescue a starving person by saying “Okay, let’s go grow more food.” That makes sense, but I still feel it might not address something here. I need to think more about it.

    And hey, at least Star Trek tried to be fairly multinational. 🙂

  3. Russ,

    I find your hypothesis and work supporting it fascinating. There are, however, a few points I don’t quite understand. So let me start right off with a question which challenges your hypothesis. Might as well jump right in, eh? 🙂

    The observation that individual countries’ food supplies don’t seem to correlate with their fertility rates as described by your hypothesis:

    I’ve read that one criticism of your work involves the observation that the countries with the lowest fertility rates tend to be the developed countries, and those with the highest tend to be those more deprived of food. (which would seem to contradict your hypothesis that more food means more population growth)

    Now, I haven’t actually seen who made this criticism, other than one libertarian columnist whose analysis I didn’t find very impressive. But from what I read, your response is basically that the US and other developed countries are exporting food to those developing countries.

    To me that doesn’t seem to go far enough. How does it explain the leveling off of fertility rates to replacement levels (or nearly so) in The US and other countries in which most people are not deprived of food? And how does it explain the high fertility rates in countries which, despite receiving food aid, are comparatively deprived of food? In fact, on average, wouldn’t people in those deprived countries be at the lower caloric intakes that cause animal birth rates to decline? What am I missing here?

    Okay, another question. And let me emphasize that these are just questions which would help me to see more clearly the implications of your work. They’re not an attempt to refute, just to inquire. 🙂

    The question of correlation versus causation.

    Trinifar mentioned this in the previous set of comments which looked at this. Your work shows a very clear correlation between the growth of food supply and that of population. Now, while I’m sure Russ knows where this is leading, let me set it up for those who didn’t have to suffer through experimental design classes back in the day. We know that if A correlates with B, it may be that A causes B, or that B causes A, or that some third factor causes both of them. In this case (Russ’s data), once the food data are converted to fit with the population data the correlation looks very strong. (As an aside, why is there not listed in the results a correlation coefficient? It looks like it would be very high.) While I suppose something like economic growth could influence both food production and population growth, it’s hard to imagine it producing such a strong correlation. i.e., I wouldn’t think it would cause both to grow so very similarly. (Anyone see it differently?) So (maybe) that more or less rules out a third factor causing the both population growth and food supply growth.

    But could it be that growth in food supply is caused by population growth in the sense that growers are pushed to constantly keep up with population/demand? I think that’s hard to completely rule out. On the other hand, the correlation looks so strong, that to me it’s hard to imagine growers/producers keeping up with population so perfectly. Yet it does seem plausible to me that if food supply is dictating population growth the correlation might look that strong. In other words, while it’s hard to say for sure, I think the correlation causation question may just fall out in favor of Russ’s hyposthesis. What say you, Russ? (or anyone else)

    Would stopping the increase in food production cause more people to starve?

    This is a common concern, as indicated in the comments under this thread on Grist. I must say, though, that the more I think about it, and read comments such as those by John Fish Kurmann and atreyger under that Grist article, the more I think it would not present an added starvation problem. The reflexive assumption is that it would lead to more starvation, but IMO some thought begins to suggest otherwise. At any rate, this is a question people will want answered.

    If we put a cap on global food production, how soon would world population growth stop?

    The more I think and read about this idea, the more sense it seems to be making. I think it might have the potential to stabilize population growth rather quickly. Is that right?

    But how would stopping the growth of food production interact with the social and economic issues known/thought to influence fertility rates?

    Would it simply override them? Would there be problems in areas where religion or culture encourages large families?

    Over some period of history, it seems we’ve tried to “keep up” with population growth by producing more and more food. I believe your contention is that we can’t “keep up” with population growth that way. The result is just more people, and ultimately more starving people. This leads to this question: Historically, did this attempt to “keep up” with population in our food production begin around the time of industrialized agriculture?

    I would think there would be some point before which no one was really thinking about keeping up in that way. I guess I’m trying to get at when this seemingly misguided effort began. Any observations on that?

  4. I second John’s questions, which are similar to my own presented here in a previous post where Steve brought up the work by Hopfenberg and Pimentel.

    [Administrator’s note: Trinifar’s comment refers to the first of my questions. The others were added later.]

  5. To Lo Fleming,

    When I first thoroughly reviewed Russell Hopfenberg’s research, I had the same reaction you have had. What Russ is reporting is “all very scary,” at least upon first sighting. However, I expect you will find, as the discussion here takes shape and Russell Hopfenberg has this excellent opportunity to comment, it could be that you will feel better about our prospects for a good enough future for life on Earth.

    There is nothing I am saying now that is intended to suggest to you that the global challenges potentially posed to humanity by the scale and growth rate of human enterprise on Earth will be anything other than formidable. Please be assured, we could soon come face to face with huge challenges; however, the human community can take the measure of the challenges before us and find solutions that are consonant with universally shared values.

    With thanks to you and John Feeney,


  6. To Russ Hopfenberg,

    John Feeney has presented legitimate questions, ones many people have wanted you discuss but been reluctant to ask, that call out for explanation.

    Of course, other questions are bound to be raised; but, without doubt, the place to begin is with responses to John’s questions.



    PS: Please note that demographers remain noticeably silent regarding this apparently unforeseen and clearly unwelcome scientific evidence. Also, consider that the research of Hopfenberg and Pimentel directly contradicts the consensually validated and widely accepted theory of the human demographic transition, that is expected to magically occur in the middle of Century XXI. That politicians and economists have willfully relied upon what may be an outdated and evidently preternatural demographic transition theory, one noticeably supportive of patently unsustainable activities of the predominant global political economy, and in flagrant disregard for the limitations and requirements of biophysical reality, could be one of the biggest perpetrations of fraudulence of all time.

  7. Steve,

    Your comments about the Hopfenberg and Pimentel work contradicting the theory of the demographic transition are intriguing, and that’s an area I’d like to hear more about. i.e., what does Russ make of the notion of a demographic transition in light of his work?

    I will say I’ve felt a little suspicious of the idea of the demographic transition, and maybe it’s because it seems to see humans as influenced more by economics than biology, seeing them as different in that way from other species. Of course the whole subject of the interplay of biological factors (as described by H&P) and human cultural creations such as economics, education and the like has the potential for much discussion.

    Also, I will be submitting some additional questions soon. (I’m just pressed for time at the moment.) In addition to Trinifar’s questions, which he linked to, others who familiarize themselves with the work will no doubt submit their own questions or comments as well.

  8. Dear John,

    Thanks, yet again, for what you are doing. I believe we will make a difference.

    Something is happening. Something may also be seriously wrong with the way the elders in my generation believe the world in which we live actually works.

    An aspect of this unexpected problem of perception has to do, it now appears, with a consensually validated, preternatural demographic transition theory. It posits that the skyrocketing increase of absolute global human population numbers will magically level off in the middle of this century and the population growth of the human species will miraculously end. Consider that it is a misperception to believe the global numbers of the human population are soon to stabilize.

    Another aspect of the unforeseen problem of perception is associated with the widely shared view that the members of the human species can continuously increase their per capita consumption of the limited resources provided by the Earth for human benefit. Consider that it is a misperception to believe per human consumption of scarce resources can perpetually occur without regard to limits to growth imposed by the relatively small planetary home we inhabit.

    Still another aspect of the unacknowledged problem of perception is connected to the specious idea that the current scale and anticipated growth rate of the predominant global economy can endlessly increase on Earth. Consider that the artificially designed, human construction of economic globalization cannot endlessly expand in a finite world the size of Earth.

    When taken together, it appears that the self-proclaimed masters of the universe of my not-so-great generation could be making a set of errors of perception, ones borne of hubris and overweening ambition, that result in an adamant insistence upon patently unsustainable forms of human enterprise and in a self-righteous denial of human limits and Earth’s limitations.

    Ready or not, like it or not, it appears the established scientific consensus on global climate change makes clear to us something apparently unforeseen and distinctly unwelcome: that more of the same ol’ business-as-usual unbridled economic growth, unrestrained per human resource consumption, and unregulated human propagation could become patently unsustainable on a planet the size of Earth, even in the first half of Century XXI.

    According to the scientific consensus on global climate change, the world we inhabit does not work in all the ways we wish it did. That is to say, a finite Earth cannot sustain an infinite increase in human consumption, production OR propagation activities.



    PS: Please send in questions regarding the research of Russ Hopfenberg. Everyone is welcome to participate.

    PPS: Russ and I had lunch together today. He is encouraged by this rare opportunity to discuss with all of you new data of human population dynamics and the human overpopulation of Earth.

  9. Magne Karlsen


    If population growth is a function solely of food supply, once might realistically have to expect to see a future development of a further eroding of the ecosystems of this planet. – Rampant overfishing, industrial farming, deforestation, etc., all because of a growing population’s rising demand for food. –

  10. Just a note: To keep these comments easier for Russ to go through, I’m going to append my additional comments and questions to my first comment above.

  11. Dear Magne,

    If the predominant human culture keeps adamantly insisting upon ever more increasing per capita consumption activities that are easily identified in our time, then I suppose your appraisal of the future is likely to be correct. On the other hand, we could choose to make things not always bigger but BETTER and SMALLER, in keeping with a human scale. Patently unsustainable per human overgrowth activities would progressively decline.

    DEVELOPMENT will become more and more prevalent in the future. GROWTH will become a thing of the past.

    Thanks for your comments.


  12. Although it is necessary to recognize and acknowledge the complexities
    inherent in cultural life and the natural world, it is equally important that a dizzying array of variables not blind us to certain scientific facts of biophysical reality. Humankind could be bound by such facts because the workings ofthe natural world exist independently of human
    wishes and beliefs.With this in mind, please note that Russ has provided an elegant model that accounts for the salient factors governing the dynamics of global human population numbers. According to his findings, the size of the human population is determined primarily by food availability. The realization that complexity and elegance are derived from different points of view—that there is complexity and
    simplicity in the world we inhabit—does not necessarily mean that one is correct and the other incorrect. To the contrary, it could be
    that each point of view is valid based on the scope of observation.

    According to Hopfenberg, the dynamics of human population numbers is no longer a preternatural phenomenon but a knowable one and human population dynamics is not essentially different from the population dynamics of other species in both the complexity and the simplicity of the governing elements.

    A point in human history may have been reached when the current scale and anticipated growth rate of economic expansion worldwide, increasing per human consumption of limited natural resources, and skyrocketing absolute global human population numbers can be seen as soon to become patently unsustainable.

    Regardless of how long a predominant culture of the human species prizes certain of its unbridled growth activities and CHOOSES TO LEAVE THEM UNCHECKED, surely it is not too late to accept limits to growth of the human economy, human consumption, and human numbers
    worldwide by altering human behavior accordingly.



  13. There’s an article on Grist right now, under which this topic has come up in the comments. It makes interesting reading, and I’ve invited the folks there to come here for this event.

  14. John

    You are ahead of the times. Your May 3rd discussion is coming along just at the right time. Many of the sites are talking about food and population.


  15. Lo,

    I’m always a trend setter. 😉

  16. I’m going to suggest that anyone else who wants to post a question or comment for Russ try to do so by Saturday (this is Thursday, April 26) if possible. That should give Russ enough advance time to review the questions/comments and perhaps some weekend time to formulate responses. You can of course post questions/comments after that; just realize the later you do the smaller the chance Russ will be able to respond, I’d think. Thanks.

  17. Dear Friends,

    As background for Russell Hopfenberg’s comments later this week, please consider the following essay. Thanks.

    The Idols of Environmentalism

    Do environmentalists conspire against their own interests?

    First in a two-part series by Curtis White.
    Published in the March/April 2007 issue of Orion magazine

    For part two of this two-part series, see The Ecology of Work.

    ENVIRONMENTAL DESTRUCTION proceeds apace in spite of all the warnings, the good science, the 501(c)3 organizations with their memberships in the millions, the poll results, and the martyrs perched high in the branches of sequoias or shot dead in the Amazon. This is so not because of a power, a strength out there that we must resist. It is because we are weak and fearful. Only a weak and fearful society could invest so much desperate energy in protecting activities that are the equivalent of suicide.”

    Read the rest here:

  18. The Ecology of Work

    Environmentalism can’t succeed until it confronts the destructive nature of modern work—and supplants it

    by Curtis White
    Published in the May/June 2007 issue of Orion magazine


    ENVIRONMENTALISTS SEE THE ASPHALTING of the country as a sin against the world of nature, but we should also see in it a kind of damage that has been done to humans, for what precedes environmental degradation is the debasement of the human world. I would go so far as to say that there is no solution for environmental destruction that isn’t first a healing of the damage that has been done to the human community. As I argued in the first part of this essay, the damage to the human world has been done through work, through our jobs, and through the world of money.”

    Read the rest here:

  19. Note to Steve and all:

    If you’re going to paste more than a brief snip from an article in a comment here, please make sure you have permission from the author. Normally, I wouldn’t so much mind as I’d just take it down if I got a complaint from the author. But the WordPress staff have been very firm in some messages on their support forums to the effect that if they receive a complaint about copyrighted material on someone’s blog they will close down the blog, no questions asked, and only might put it back up if the material in question is removed.** So I don’t want to take chances with that.

    Steve, if you know Curtis White could you check to see if reprinting those here is okay with him? Otherwise, you or I could just provide a link to them in Orion. (Same thing with the Dave Foreman essay. And if you know him, man you know everyone! :^)


    The management 🙂

    **That’s also why I only use photos here which are licensed in ways that don’t raise any copyright issues. Based on what I read on the forums, I think bloggers on blogs need to be a little extra careful about that.

  20. Dear John and all,

    It appears that I have made a mistake here. Dave Foreman and Curtis White look to me like two of our most wondrous “voices in the wilderness”…..voices that need to be heard. I do not know either of these outstanding thinker-scientists personally. Consequently, this week I will find them and ask each for this permission. If I do not obtain the permission, then I will advise you of same, at which time I suppose the articles of both men will be exchanged for the link or, perhaps, it would be satisfactory simply to add the link on each post.

    Thanks for bringing this situation to my attention.



  21. Steve,

    Another commonly used option, and perfectly acceptable under “fair use” guidelines, is just to paste the first several sentences (or perhaps the first paragraph) of the article, followed by a link to where people can read the rest. That might be the easiest approach on an ongoing basis. You don’t need to be running around trying to get permission from the author every time you want to call attention to an article. It’s no big deal; let me know which option you want to take, and I can fix each comment from my end in a matter of seconds.

  22. Steve,

    I went ahead and truncated the articles and provided links to read the rest. I think it’s probably the best way to go because even with permission from the author, pasting a whole article in a comment makes for a very long scroll. Thoughts?

  23. Hi John,

    Excellent effort on your part. I will follow your example going forward.



  24. Tomorrow Russ Hopfenberg will provide responses to questions submitted to him.

    John Feeney , Trinifar, Magne Karlsen and Lo Fleming are due thanks for preparing the way for this opportunity to openly consider apparently unforeseen scientific evidence of human population dynamics and the human overpopulation of Earth. Who knows, this discussion could be a useful process by which the most formidable of humanity’s looming global challenges is carefully and skillfully examined.



  25. Pingback: Special guest: Dr. Russell Hopfenberg on food supply, carrying capacity, and population « Growth is Madness!

  26. Pingback: Russell Hopfenberg on food supply, carrying capacity, and population: follow-up responses to readers’ comments « Growth is Madness!