As many of you know, I’m starting to write a book that describes a utopian future state where humans actually live in peace, and in harmony with the other species on Earth. Everything I describe (in the story outline anyway) is plausible except a solution for overpopulation. Six or seven billion humans, even living more modestly and conscientiously than we do now, simply can’t co-exist with the rest of the species on this planet. There’s just not enough room, not enough resources. The numbers can’t be crunched to make it work.

Ecologists have computed that, if 88% of the habitable Earth’s surface is allotted to humans (the other 12% is left for all the rest of the species on the planet), Earth could support about one billion humans at a comfortable and sustainable level of existence. There are two problems with this. The first is that, human nature being what it is, humans won’t limit their resource consumption to ‘a comfortable and sustainable level of existence’. The second is that biodiversity doesn’t work that way — it’s a web of interdependencies, not a zoo, and human population must be balanced with levels of other species or the whole ecosystem collapses, as is occurring now.

Global human population was about 150 million for most of the first three million years of our species’ existence, jumping to about twice that number by the sixteenth century as humans populated most of the planet. Virtually all increases since then are due to lowering of death rates as a result of improvements in hygiene and medicine. That would seem to suggest that a natural, sustainable human population that would leave the rest of the global ecosystem unharmed would be about 300 million. Acknowledging that these numbers are wild approximations, and that someone should be doing some serious work in this area (I could find no professional research on this subject on the Internet), let’s further assume that the dramatically increased resource consumption per person since the Middle Ages is roughly offset by dramatic improvements in the efficiency of resource use. In other words, our ingenuity approximately offsets our greed.

This level of human population is not only ideal for the ecosystem: It’s a level that would allow us to reclaim the age of leisure we gave up 30,000 years ago. According to the latest anthropological theories, man lived a simple, easy and pleasant life until then, working perhaps an hour or two per day to meet his food needs comfortably. Furthermore, there is evidence that famines, wars, and epidemic diseases were virtually unknown at that population level: the stress of overcrowding and competition for food, and the concentration of numbers sufficient to spread disease simply weren’t there. If we could somehow reduce human numbers back to that golden 300 million level painlessly, there is every reason to believe that we could regain paradise.

In theory, could this be done? Let’s assume that the vast majority of humanity suddenly understood this, and reduced their family sizes to bring human numbers down to a sustainable level, by, say, having an average of only one child per couple (less than half today’s rate). It would take a half century of this lower birth rate just to stabilize the population at today’s level, because of the current demographic pattern and the time lag required before the drop in birth rate impacts the peak population demographic and those of reproductive age. After that population would drop about 1% per year, reaching the 300 million level about two centuries from now. The percentage of humans in the 20-65 working age group would drop gradually from the current 55% to about 40% and then start rising again. Therefore, since the extra burden of the aged would be significantly offset by a drop in dependent children, the demographic shift should not create a labour or social crisis.

So it’s feasible on paper, but…

  1. It would take a huge cultural change to bring about this sudden drastic drop in birth rate, especially in the underdeveloped countries where birth rate is currently highest. Even with the dampening impact of massive AIDS fatalities in Africa, and an expected sharp drop in birth rate, the population of that continent is forecast to grow from 900 million to two billion by 2050. India & Pakistan’s population is likewise forecast to grow 50%, an increase of 700 million by that year. Large increases are likewise forecast in the Mideast, parts of East Asia, and Latin America.
  2. Human nature, bolstered by religious dogma, would almost certainly push the birth rate back up when the total human population started to significantly drop. Parts of Europe are already falling in population, but the rate of decrease is leveling off. To be able to sustain negative population growth for two centuries is almost inconceivable.
  3. Our rate of increase in resource consumption per person needs to be cut to zero as well, which would require a grand ‘North-South contract’ — Those in the affluent Northern countries need to agree to cut resource consumption per capita at least by half, and allow those in the South to increase theirs, in return for dramatically reducing their birth rate. The chances of this happening, and soon, are next to zero.

So it’s discouraging. While the elements of the solution are tantalizingly close, we are simply too late, and too disorganized, to be able to make the solution happen. It’s like we’re navigating an oil tanker headed for the rocks and have steered away from them, but know there just isn’t enough torque, momentum change and turning diameter to avoid catastrophe, even as we watch it happening in apparent slow motion. This catastrophe — environmental apocalypse, annihilation of species diversity on Earth, famine, climate change and massive social upheaval — will likely occur late in this century or early in the next, as population balloons to 10-15 billion before leveling off (depending on whose projections you believe) and aggregate human resource consumption increases by a factor of ten. It will be a disaster 30,000 years in the making, because we squandered the last chance to prevent it, perhaps generations ago.

But we can’t of course give up hope. I believe we need to start to build a global consensus on the need to reduce our human numbers to 300 million (the same level as in the Middle Ages), or some other level that scientists can agree on as sustainable and healthy. And for those in the North to also halve our individual ecological footprints. We need to start telling the story of how wonderful, magical, perfect life could be, for all of us and all other creatures in Earth’s web of life, if we could achieve these reductions. The book I’m writing is an attempt to describe that possible utopia. And it is a work of fiction. I’m just trying to envision it not being a work of fantasy.

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  1. Camilo says:

    You know, overpopulation is a self-correcting problem. Only I am afraid the human species won’t be around to witness it.

  2. Jon Husband says:

    Thanks for this brief and clear piece, Dave. It has inspired me to do more of what I have been doing for the last three or four years, which is to reduce my ecological footprint as much as is possible (I’m probably overstating my effectiveness here), and continue to make the case to my wife for not having a child (I’m not being a meanie, I do think it’s a serious issue).

  3. Dave Pollard says:

    Jon — bravo. There is always the option, of course, of adoption, and, for those not lucky enough to be already married, finding a mate who already has a child from a previous marriage.

  4. silly me says:

    Possible unintended consequence of 300 million world wide population is the reduction in intellectual capacity. That number is a very small number of people. How many more intellectual problem solvers would there be with a world wide population of 1 Billion? How many fewer David Pallard’s or Einsteins and what are it’s consequences? (I think Isaac Isimov used this premise in one of his Works in Science Fiction)Regarding Biodiversity etc… The earth has gone through several Biodiversity contractions. The mass extinctionsThe five more significant well-known mass extinctions are the extinctions at the Ordovician/Silurian, late Devonian, Permian/Trias, Trias/Jurassic and Cretaceous/Tertiary limits, the most significant being at the P/T limit, the most well-known at the K/T limit (Gore Rick 1989, Sepkoski J.J.Jr, 1986).If the mass extinctions reality is an object of consensus in the scientific community, the causes of these extinctions induce many and debatable assumptions. The extinction at the K/T limit caused a flourish of hypothesis, some of them are serious, like the marine regressions and climatic deteriorations which resulted from this (Ginsburg 1964), others rather whimsical or speculative like the supernova thesis, a viral epidemic, groups senescence, etc… The theory in vogue of a meteorite impact with the earth (Alvarez 1980) is the most popular….Then taking this into account: Mathematical Model for Mass ExtinctionIntroductionOf all the species that have lived on the Earth since life first appeared here 3 billion years ago, only about one in a thousand is still living today. All the others, the vast majority, became extinct, typically within ten million years or so of their first appearance. This large extinction rate has had an important influence on the evolution of life on Earth – the population and repopulation of an ecological niche by species after species allows for the testing of a much wider range of survival strategies than the slower process of phyletic transformation by which a species gradually adapts its morphology and behavior to its surroundings. This in turn has contributed greatly to the current level of biodiversity on the planet. There is nothing however to suggest that the species alive at present are special in any way. Presumably they too will become extinct within the next ten million years or so, and make way for successors themselves. The importance of extinction to the development of life leads us to some crucial questions about the process, the most fundamental of which is this: is extinction a natural part of the evolution process, or is it simply a chance result of occasional catastrophes besetting either single species (such as diseases) or larger groups of species (such as changes in the salinity of the sea, or changes in the climate)? Many talented thinkers have offered arguments on either side of this debate. We suggest that the truth lies somewhere between the two opposing points of view, and present a model demonstrating how the evolution process might interact with environmental stresses to produce a distribution of extinctions very similar to that seen in the fossil record. A detailed writeup of the model is here. For the moment we just present the main results. …Now that we as a species are on the virge of being able to create a host of new creatures. One has to wonder if we’re not locked in whether we want it or not?

  5. Dave Pollard says:

    Silly: Not an ‘unintended’ consequence at all. The extrapolation of that argument, of course, is that if we hadn’t invented birth control there’s be 12 billion by now instead of 6 billion, and maybe in that extra 6 billion would be ‘the second coming’. Three hundred million isn’t ‘very small’. It kept us alive and thriving for three million years through several ice ages. As for extinctions, I think it’s tautological to say they’re ‘natural’. The major extinctions you refer to, however, the largest two of each now being credited to a meteorite and a massive volcanic eruption respectively, were not evolutionary, but rather revolutionary, as these events caused a sudden massive change in the planet’s biological makeup. Between such non-evolutionary, random events, biodiversity always tends to increase, and extinctions are rare and almost always offset by appearance of other new, better adapted forms of life. That is, alas, not the case with the current biodiversity crash, which is evolutionary, but which is producing what is probably the first occurrence of non-random, preventable mass extinction in our planet’s long and remarkable history.

  6. Chris Dent says:

    The gee-whiz solution to this problem in the sci-fi books has usually been to colonize somewhere else in some kind of multi-generational movement that has the feel of religion. It fixes the economy (research funding to figure out how to do it, enormous amounts of labor required), it addresses the Asimov problem of not enough geniuses by allowing the population to explode just over more ground, and it solves the war problem by giving people a shared belief and mission. Julian May and David Brin are good in this genre.Of course, the motivational factor is usually some kind of near disaster. We have a near disaster now but it’s on the other side of the curtain. A curtain that people don’t want to raise.The sci-fi vision is probably less likely than the near impossibility of getting people to stop having babies.Dave, in your research did you find any organizations that support negative population growth that do not also support racist/nationalist immigration policies?

  7. O RLY YA RLY says:

    Have you read META CITY/DATA TOWN by MVRDV (

  8. Rob Paterson says:

    Hi Dave – Another ace post. I now feel that we are on a trajectory for a bust. Maybe we will get back to 300 million but the trip will not be smooth.I can’t help but think about Rome in the 400’s. Rome at 400 had a population of about 2 million. By 500 a population of 20,000. One of the key drivers was a collapse of the factory food system and the transportation system that supported it. Don’t we face the same risk now? Most cities have a 3 day food supply.All I know for sure is that history is not a smooth curve but periods of stability punctuated by bifurcations. Doubt we can “manage” our way through this to a soft landingA great fiction book might be to work out a future for the next 100 years. I just finished Kim Stanley Robinsons alternative history of the world The Years of Rice and Salt – worth a look. He is so good at creating “worlds”. I look forward to seeing your work Ddave

  9. Doug Alder says:

    Dave – the solution is staring you in the face. Look around at all the developed nations. What do they all have in common – negative natural population growth. The only way that countries like Canafa and the US continue to grow in population is through immigration. The reason for this is simple but often overlooked. As “prosperity” that is good nutrition, health and social stability grows the need forlarge families decreases. The lower the infant mortality rate the lower the population growth curve is because the pressure to have more in case some die dwindles. Solve the problem of nutrition and health care for underdeveloped countries and the population problem will eventually take care of itself.

  10. lightning says:

    Solve the problem of nutrition and health care for underdeveloped countries and the population problem will eventually take care of itselfNo.Solve the nutrition and health care problems in underdeveloped countries and you’ll have a massive population explosion. This is where our current population explosion comes from, remember?What really works is1. Economic development. With prosperity, the marginal cost of each child increases. In a subsistance economy, another child is an extra pair of hands. In a developed economy, an extra child is an extra college education to pay for.AND (gotta have both!)2. Give women control of their fertility. Men tend to want as many children as possible, come what may. (This is actually the more important of the two)Saying that “we all have to get together and agree to cut back” simply means an imposed bananna-republic aristocracy, with the few at the top (who, I assure you, will not be “cutting back on their use of resources”) telling the peons what to do. “Sorry, no fresh water for you. Somebody else needs it more than you do.”Water runs downhill. People want to improve their lot in life. Deny either of these, and you’re looking at a disaster.

  11. John Robb says:

    I agree with the previous post. Ongoing negative population growth is the wave of the future for developed economies (who has time for kids when you are wealthy?). The greater the number of developed economies, the larger the global impact on global population. The key is economic integration. A good bit of analysis would be to determine when or if the requisite level of economic progress necessary to initiate declines in population will arrive on a region per region basis. Also, there is reason to believe that oil production globally has peaked and will fall by 1% a year from now on. How will that impact the ability of arriving economies? Of course, word to the wise, don’t fall into the same trap as the Club of Rome.

  12. Dave Pollard says:

    Chris: Unfortunately, negative population growth is such a politically explosive issue that no one is willing to touch it except the nut groups, who all seem to come with discrediting baggage. People can’t disassociate it from ‘eugenics’ and other discriminatory population control advocacies. I remember writing to Paul Ehrlich on this back in the ’60s and even he, who subsequently discredited himself with other dubious claims, wouldn’t talk about negative population growth. Even ZPG has taken a euphemism to make it sound less threatening. Waffling everywhere when what is needed is someone to call a spade a spade.

  13. says:

    I don’t know the solution, but I do know where to get some clues. Two words: Buckminster Fuller

  14. Dave Pollard says:

    Harald: Tell me more. The blurb just suggests that it’s about representing a city with digital data. Not clear what this has to do with population?Rob: I’ll check it out, since also described this book in glowing terms, and even though I’m not much of a reincarnation fan.

  15. Dave Pollard says:

    Doug/lightning/John: Just because developed countries have reached ZPG doesn’t mean the answer is to make other countries richer. In fact, the UN forecasts presume exactly that — that by the latter part of this century every part of the world will have reached ZPG by emulating the Western/Northern trend. But by then there will be 9-15B people. And the aggregate resource consumption to reach that level of affluence will have risen by a factor of ten. And the Western/Northern population ‘dip’ (seemingly a prediction of negative population growth) is illusory due to demographic shifts — computer models basically say that Western/Northern populations, ignoring immigration, will have periodic booms and busts but overall level off at very close to replacement level, even if women take control of fertility worldwide (educated and affluent women overwhelmingly want small families, but that means two children, not one or zero). And a constant 9-15B at Western/Northern consumption levels is utterly unsustainable, a prescription for eco-collapse. I also agree with lightning that we can’t impose a solution, at least not a political one. That’s why I’m so pessimistic. Maybe instead of The World That Could Be I should call my book The World That Could Have Been and bury it underground so that the next visitors to this planet, or the survivors of the coming extinction (scientists think the most robust survivors will be insects and birds, but I like to imagine they will evolve into faeries) can read it and appreciate that at least some of us saw what was coming and did what we could to prevent it.Boy, now I’m really depresssed.

  16. Dave Pollard says:

    Gregor: I’m a Bucky fan, and Gary Murphy (see my blogroll) keeps quoting him on his blog and in his comments to me. Especially like his quote about the need to replace a system that doesn’t work, rather than reforming it. I only wish I shared his optimism. I’m ambivalent about technology solutions — they’re the proverbial double-edged sword. BTW thanks for the Hober link — are you associated with the radio station?

  17. Dave Pollard says:

    That’s a terrible rephrasing of my favourite Bucky quote. Here is it, for those that aren’t tired of reading it: “You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete.”

  18. Jon Husband says:

    Seems to me that the only tools we have to do so are each other, the interconnectedness afforded by the ‘Net and maybe smart software.The other stuff, like economic philosophies, capital markets, mental models, and legal infrastructure are pretty damn big obstacles.While it would be great to build under the existing foundatiuons, my guess is that the “boom-and-crash” sound of things falling apart faster and faster will be pretty loud.An interesting read is “The Fourth Turning – An American Prophecy: What the Cycles of History Tell us About America’s Next rendez-Vous With Destiny”

  19. Dave Pollard says:

    Thanks Jon. I don’t expect much boom and crash. I think that’s the problem. We’re like the frog in the water, slowly adapting to the rising temperature until we boil to death. Or, as Eliot put it, This is the way the world ends, not with a bang but with a whimper.

  20. The problem, Dave, is finity. Our current free-market model posits unlimited growth. Or managed growth, which is oxymoronic. See my posts of 1/28/03 and 2/08/03 for some thoughts on limits to growth.

  21. Jon Husband says:

    Thanks, Dave – and I agree with the “frog in the pot” allegory (which I first enountered in The Age of Unreason, by Charles Handy – no doubt you know the book).What I meant by “boom-and-crash” (a poor choice of words) was that as it becomes more and more apparent that our systems are skewed, unsustainable, etc., empty surface action (sound and fury, signifying nothing) will increase – more of the “your money belongs in your pockets, we’re doing this for the American people” hyperbole and unashamed fabrication of reality that keeps the frog in the pot.And yes, it feels all too often like all we can do is whimper.

  22. Gregory Dance says:

    If stopping the wests excessive consumption of resources and redistributing wealth / power to the developing world in order to achieve ZPG is the mission, them why not consider this idea.Multinationals run western governments and WE indirectly run the multinationals, don’t we?We give them power by buying their products & services, so stop doing this and you will soon see their tune change! Soon after political agendas will change also.

  23. O RLY YA RLY says:

    Dave: sorry it took some time (been moving). META CITY/DATA TOWN is indeed about an innovative way of representing data. The data they’re representing however, are the space and resources people consume. And the different results you get from different solutions. At least, that’s how I remember it (it’s still in a box, somewhere…).

  24. Travis says:

    I don’t think overpopulation is a problem intrinsic of the human species. In my mind, this idea of overpopulation is quite a short-sited view of human potential. I explain it as follows: There’s this idea of population, there’s a Carrying Capacity; there can only be so many of a species within an ecology, a maximum, and this is regulated like a cycle, such that there’s prey and predator, when prey population goes up, predator goes up as well through consumption, causing prey levels to drop, followed by predator. This is how population is maintained in animal population.But here’s the key fact that one must understand, and something, in one manner, that I’ve already proven. Humans are not animals. Physiologically, we are, but not cognitively. We have the ability for hypothesis, and this has allowed us to step out of the population wax and wane cycles. If humans were merely opposable-thumbed hairless apes, there is no way there’d be 6.3 billion of us at this time. I bet, we’d be right at 300 million like Dave says.I’m not saying that overpopulation couldn’t be a problem, because as it stands now, there are serious geopolitical problems with the world, and if humans can’t stop this global raw material looting, and start focusing on enhancing the only resource important, the human mind, then overpopulation will be a problem just as Dave has said.I’ve never read Buckminster Fuller, but he seems to have some of the same ideas that I have. I should pick up one of his books.

  25. Niels K says:

    I don’t see a way of solving the overpopulation problem – and like Dave, I see it as a crucial problem. But I have another facet to add. I think that digging deeper into the reasons why our planet is overpopulated will change the way we feel about it – and that’s at least something:It appears to me that overpopulation is a direct consequence of modern medicine – because it is modern medicine that’s behind our increased life spans and our dramatically reduced mortality rate. Or isn’t it?Assuming that it is, why is it then that these so called successes of modern medicine, which our civilization is so overly proud of, have brought about a condition of overpopulation on this planet so grave that it endangers the survival of our species?My answer: Because modern medicine is not what we think it is.The experiences I’ve made in my life so far have given me the impression that whatever the physical problem we have, it’s always a consequence of some aspect of the lives we lead. It’s always a consequence of some aspect of our personality. It always expresses something. Something which is otherwise not heard.I’ve come to see health problems as signposts – which show us aspects of our personalities which we otherwise neglect – but which require attention.Modern medicine, on the other hand, has what might be called a victim’s philosophy. We’re just victims. Victims of viruses, of bacteria, of cancer cells, of whatever. They are the bad guys – they are responsible. And modern medicine is the mighty instrument we have at our disposal to fight these enemies.In my eyes, this is about the worst lie circulating on this planet. The way I’ve come to see it, what we really do with modern medicine is fighting symptoms pretending they’re the problem – when the symptoms were here to show us the problem.I very seriously feel that what we do with modern medicine is fighting against ourselves – fighting against human nature. We are doing all we can to not see the real problems we have – eventhough the journey to real health would certainly be to face these problems.So it appears to me that our overpopulation problem stems very directly from an attitude of fighting against human nature – as opposed to going with the flow of life – of allowing things to happen the way they naturally would – which is probably the way which would be best for us and all others.But then: Aren’t we fighting against human nature anyway? Isn’t this a universal subject on our planet? We kill and torture others, we destroy nature even though we’re part of it, we treat children in totally irresponsible ways, preventing them from being able to develop into whole, healthy beings, we cheat each other where we can for personal gain … Isn’t this all one great fight against human nature? Against ourselves?So I’ve come to see the overpopulation problem as just another consequence of something bigger, going on here on this planet, which might be summed up as living against nature. And I think the key to coming to terms with this would be to understand why it is happening.While I don’t have an answer to this question, at least I got an interesting hint about it some time ago: Someone I was talking to claimed that there had been several civilizations on this planet (not just the one we know of), and that they all had a purpose, so to speak – the purpose of the present civilization being to experience what happens if we live against nature.If that’s true, then we’re just on the right track …

  26. DENNIS CLANTON says:

    I know the world will survive,the real question is what will it contain.People as a whole are not going to do this voluntarily but will wait till nature presses the reset button on us.Man is a legend in his mind!lol Technologists keep digging us a deeper hole with their bandaids. The later the reset comes the worse its going to be.Either we start fixing the population issue or nature will(not fun being ruled from the bottom up).Our population and consumption will eventually if sustained will have even worse results then imagined if this pace is sustained as oxygen levels will fall below liveable levels.(space suits on earth?! lol)

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