Peak oil and the third demographic transition: A preliminary model

This is a guest post by Dr. Gary Peters, retired geography professor and author of Population Geography.

The growth of the human population cannot continue forever—there is a limit to our numbers, even if we cannot specify what that limit might be.  There is also a limit to how much oil can be extracted from our planet, even if we don’t know exactly how much oil there really is.  These two variables are related because cheap oil has allowed us to support a population that is much larger than it would be otherwise.  Despite more than 200,000 years of living and growing, the population of Homo sapiens never even reached one billion before the beginning of the era of fossil fuels.  Today there are nearly seven billion of us and much of the era of fossil fuels is becoming visible in the rearview mirror.  Demographers have suggested two demographic transition models to explain what has happened to the human population over the last two centuries.  I’m suggesting that a third demographic transition model will be necessary to explain what is likely to happen in coming decades.

The first demographic transition. The original (or classical or traditional) model of demographic transition had its genesis in the work of Warren Thompson, dating back to 1929.  Though improved in many ways since then, essential features of the demographic transition model remain simple and well-known, as shown in the illustration below.  Economic growth drove demographic changes in ways never seen in earlier pre-industrial societies.

The basic demographic transition model is based on historical declines in mortality and fertility that occurred from the eighteenth century onward in several European populations.  Though the model is not a good predictive device, the demographic transition has continued in many non-Western countries as well.  It is often cited as the reason why we should not worry about future population growth.  In simple terms, economic growth is seen as the driving force behind the demographic transition, so all we need in today’s poor countries is economic growth.  That will bring population growth to an end.

The end point of the first demographic transition was thought to be an older stationary and stable population corresponding with replacement level fertility (a total fertility rate of approximately 2.1) and life expectancies of 70 years or more.  Demographers thought that there would be a balance between crude birth and death rates, so the population would not grow unless natural increase was supplemented by immigration, which most thought would be unnecessary.  They argued that this demographic transition would gradually encompass the world; nuclear couples everywhere would converge on a demographic ideal—two children for the most part.

There were two problems with this simplistic conceptualization of the demographic transition.  First, nothing in either history or human behavior suggested that any society, let alone all societies, would converge on a pattern of marriage and reproduction that would stabilize population size.  Second, starting with Thompson and continuing today, the demographic transition model has not been set within the broader context of the rising use of fossil fuels that has characterized the last two centuries or more, a revolution in energy availability that would prove to be unsustainable.

The second demographic transition. The second demographic transition, first described by Dirk van de Kaa in 1987, was a response to observed fertility rates in many European countries that were dropping well below replacement level.  This model sees no such equilibrium between births and deaths as the end point of demographic transition. Rather, new developments in different societies have presented more varied arrangements of marriage and reproduction than were first imagined by demographers.  Not only have we now observed sustained sub-replacement fertility in many places, we have also witnessed a variety of living arrangements other than marriage, the disconnection between marriage and procreation, and even depopulation in some cases, primarily among rich countries, from Japan and Germany to Russia and the Ukraine.

Because neoclassical economics depends on sustained growth (an oxymoron to anyone outside of economics), the thought of depopulation has created concern, if not outright horror, among numerous economists.  At the same time, because they still believe that economic growth will bring population growth in poor countries under control, they worry not in the least about the demographic futures of places like Bangladesh, Pakistan, or Saudi Arabia.

The third demographic transition. The second demographic transition came about when assumptions of the first one, especially the assumption of an equilibrium between births and deaths, proved to be too simplistic.  The second demographic transition introduced new ideas about marriage arrangements and reproduction and suggested that depopulation may occur in many rich countries in the years ahead.  However, neither of these transition models gave any consideration to the broader world economic context within which they were set.  A part of that context has been easy access to cheap fossil fuels and the rapid diffusion of industrialization.

Both the first and second demographic transitions assumed that mortality would decline to very low levels, leading to long life expectancies.  They differed in their views of fertility.  However, neither model considers that the historical period in which demographic transitions have occurred is one in which abundant and cheap fossil fuels resulted in substantial increases in productivity, both in agriculture and industry.  With the demographic transition people were swept out of rural areas and agriculture into cities and industry, then into services, a pattern that continues today in numerous places.

Russia provides a glimpse of what we may recognize as the third demographic transition, one in which mortality rates rise again, bringing about not just an equilibrium in which population finally stabilizes but a period of depopulation that gradually encompasses much of the world.  Nothing in either the first or second demographic transition models predicted what has happened in Russia, as is apparent in the figure below.

This third demographic transition, still preliminary at this point, will force us to focus on mortality, which will begin to rise as cheap oil disappears over the horizon. Signs of this are appearing regularly, as we see in the figure below, with its food price spikes and general upward trend in food prices since 2002.

Though many economists and others praise the “Chinese economic miracle,” few if any credit it in large part to the decision to initiate a one-child policy in 1979, a policy that has led to a current Chinese population that is about 400 million less than it would have been otherwise. Add those 400 million into China today and there would be no Chinese economic miracle to talk about. Had that Chinese lesson been followed three decades ago throughout the poor world, then chances of the poor countries reaching demographic stability and achieving better living standards would have been greatly improved.

Instead we continue to add more than 80 million people to the world each year, almost entirely to the poor countries, and economists keep ensuring them that all will be well in the long run because economic growth will save them from themselves. Since the United States consumes about a quarter of the world’s energy resources, with less than five percent of the world’s population, the promises of economists have always rung hollow. But they ring even more hollow today as Japan struggles with recovery from its devastating earthquake, tsunami, and nuclear disasters and unrest continues to spread throughout the North Africa and the Middle East.

We have to question the promise to the poor countries that economic growth will solve their demographic problems. That was not the case in China and going forward it will not be the case in most poor countries because the rising cost of fossil fuels will not be able to deliver the needed productivity increases. The Ponzi scheme of neoclassical economics, based on the faulty assumption that growth can continue forever, is edging toward its Bernie Madoff moment.

The third demographic transition model is based first on an assumption of the obvious: Population growth cannot continue forever. Beyond that, it assumes that the era of cheap fossil fuels has ended, no matter what effort is made to maintain it. That assumption is based on the fundamental concept that oil is both an extraordinary source of energy and finite in supply. In addition the model assumes that food production will decline worldwide as oil becomes more expensive. In turn that will lead to higher food prices, so feeding the poor will become ever more tenuous. This trend will be further exacerbated as rich countries, especially the United States, turn more to using food crops and cropland to produce liquid fuels to continue what James Howard Kunstler has dubbed “happy motoring.”

Needless to say, the third demographic transition will not only curtail population growth in the decades ahead, it will lead to depopulation as our numbers decline back toward more sustainable numbers. I doubt that Earth will see the 9.15 billion people that the United Nations projected in its medium variant for 2050; even the 7.96 billion in its low variant seems highly unlikely. After all, that is a billion more than we have today.

About Gail Tverberg

My name is Gail Tverberg. I am an actuary interested in finite world issues - oil depletion, natural gas depletion, water shortages, and climate change. Oil limits look very different from what most expect, with high prices leading to recession, and low prices leading to financial problems for oil producers and for oil exporting countries. We are really dealing with a physics problem that affects many parts of the economy at once, including wages and the financial system. I try to look at the overall problem.
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43 Responses to Peak oil and the third demographic transition: A preliminary model

  1. Pingback: Peak oil and the third demographic transition: A preliminary model

  2. Mandy Simons says:

    In a far future, the increase of population in the third world could be partly compensated by a decrease in western countries, which is already starting to happen. However for the shorter term world population is still expected to continue to grow, but what is the actual maximum number of people that can be suppported by our planet? It would be interesting to know an approximate limit number (more discussion at

    • Gary Peters says:


      The only valid answer is “no one knows.” The range of numbers that people have come up with varies from less than a billion to more than 50 billion.

  3. Arthur Robey says:

    And then there is someone else who has no common sense.
    Aubrey de Grey who wants to live forever.

  4. Gary Peters says:

    Here are some interesting facts published recently by Dr. John Coulter in Australia. They give some perspective to what conditions are like in Egypt. At its current growth rate of 2.1 percent Egypt’s population will reach more than 160 million by 2045.

    •Egypt’s population in 1960: 27.8 million
    •Population 2008: 81.7 million
    •Population tripled: in a mere 48 years
    •Rainfall average over whole country: About 2 inches annually. It’s a desert!
    •Arable land (almost entirely in the Nile Valley): 3%
    •Arable land per capita: 0.04 Ha (400 square meters or an area just 20 by 20 meters)
    •Food imports: 40% of requirements
    •Grain imports: 60% of requirements
    •Oil exports: Declined 26% in 2009; oil production has peaked and is falling
    •Oil exports to fall below imports: 2010-11 Cost of oil: rising steeply (cost of oil & food tightly linked)

    • schoff says:

      when I see that 400 sq meters, I realize again that I’ve won the lottery being born in the US. my garden is bigger than this as is my chicken aviary. Incredible.

      I’d like to return to the contraceptive issue, if people are worried about the pill and the complex that makes it happen, we’d have bigger issues with insulin. I believe I just saw where they were projecting 50% diabetes in urban poor America, loss of insulin for type 1 would be a death sentence in a couple
      of months. Maybe this would be America’s version of Orlov’s people just dissapeared.

      What really interests me in the demographic analysis is the “fitness” of the people in “power down” or “descent”. While insulin might be a metric, one would be interested in skills, experience, or even “will”. I’d like to believe that my amish neighbors are fit, but my mother’s suburban neighborhood I would question their non-garden yards, maintained by others, as they drive their bmw’s to be lawyers and bankers. It is possible that there are people like her husband (who has a big garden and maintains his own yard), who grew up on a hard scrabble dairy farm, but i doubt it.

  5. Peter T says:

    Has anyone looked at demographic trends in failed states (other than the FSU)? I believe the population of Zimbabwe has dropped, due to rising mortality and emigration. What about Somalia? I know its hard to collect numbers in a war zone, but my impression is that in a number of countries where living standards have gone backwards population is still rising.

    • Arthur Robey says:

      Bob Mugabe said that he thought the optimum number of people in Zimbabwe was 5 million.
      He had 11 million.
      He will be judged as a failed dictator. The population is growing again, in spite of his best efforts.
      The truth is people are a commodity. Their value is inversely proportional to their number.

      • Gary Peters says:

        Zimbabwe now has 12.6 million people according to the Population Reference Bureau; Somalia has 9.4 million. The annual rate of growth is much higher in Somalia than it is in Zimbabwe.

  6. Arthur Robey says:

    “What ever happened to old what’s-his-name?”

    Dimitri Orlov describes the population crash in the FSU.
    He said that one does not not notice the collapse.
    It is only if you poke your nose in at the morgue that you suspect that something strange is going on.

    Culture plays a big part in the fecundity of females. The culture in sub Saharan Africa enforces maximum utility of wombs. It must be annihilated .

    Economies would be wise to reject the discredited American dollar, and accept payment in something of value. Women.

    We are about to go into space, and the earth will support the dregs of the population.

    • Gary Peters says:


      There is no reason to believe that humans will ever colonize another planet, so it would make sense to do a much better job of managing life on this one, starting with bringing population into better balance with Earth’s carrying capacity.

      • Jan Steinman says:

        I suspect Arthur had his tongue in his cheek, and forgot to add the little smiley face… 🙂

        • Gary Peters says:


          You’re probably right. On the other hand even Steven Hawking has suggested that humans need to give serious thought to colonizing outer space. I’d happily make up a list of candidates!

          As for immigration, it seems likely to continue, and probably accelerate, in the years ahead in part because, with the exception of the U.S., most rich countries have low birth rates, aging populations, and growing labor shortages. Poor countries, on the other hand, have a surplus of people but few opportunities. Virtually all population growth now occurs in the poor countries–80 million or more each year. Many of them will be heading to where the jobs are, though they will not be greeted everywhere with open arms.

      • Arthur Robey says:

        After escaping this gravity well, why would you want to trap yourself down another? Planet surfaces will be where we drop our miscreants.

        As far as making this tiny blue dot the sole repository of the human genome, that is the route of extinction. This desire for safe seclusion is a symptom of the death wish.

        Humans have never been content to sit placidly in one place. It is not our forte. We are not vegetables. If you confine us we will get up to mischief. Ask Genghis Khan and the Boys.

        • Jan Steinman says:

          Ah, so you were serious!

          I think humans take themselves way too seriously. We’re just another primate who happened to be a bit more clever than the others — enough to oppress or extinguish our competition. The fossil record in general does not seem to indicate that nature often rewards cleverness (large brains) with longevity of the species.

          But I confess a certain fascination with the concept, and was an avid science fiction fan many years ago.

          Unfortunately, I think the retiring of the US Space Shuttle fleet this year is the death knell for such dreams. It looks like we simply won’t have the energy to do such things in the future. With petroleum gone, how many solar panels and wind turbines will it take to launch a rocket?

          Sorry, folks, but the yeast has failed to escape the cider jug, and will consume all its resources and die in its own excrement.

          Then without the oppressive weight of human pressure, perhaps the bonobos or canines or dolphins can have a go at evolving into a space-faring species. If it takes a few tens millions of years, we may be their petroleum that allows them to escape the cider jug! Let’s hope enough artifacts survive so they can learn from our mistakes.

        • Bicycle Dave says:

          Hi Jan,

          I’m with you!

          Avatar is my all-time favorite movie and James Cameron is my hero – well, after Carl Sagan. I also confess to really liking my Android smart phone. In fact, I made a living for some 35 years developing computer software. So, I guess I qualify as an honorary Geek.

          I find the notion of saving human-kind by colonization of some other planet to be beyond bizarre. The actual mechanics and physics of this is utter nonsense. I suppose there is an infinitesimally tiny possibility to hibernate some people and fire them off via rocket ship in a desperate attempt to find a habitable planet somewhere in outer space. What is the probability of success? Maybe a billion to one? So, then what? What does this matter to billions of people dying a miserable death on this planet?

    • Jan Steinman says:

      “Dimitri Orlov describes the population crash in the FSU. He said that one does not not notice the collapse.”

      I think he also mentioned that you don’t really notice that nearly half the people have “gone away” until you look in an old high school yearbook, and realize that half the people in the photos are dead.

      Humanity will go out with a whimper, not with a crash.

      • Arthur Robey says:

        I think that you have all got a bad dose of Common Sense.

        “Common sense is the collection of prejudices acquired by age eighteen.” Albert Einstein.

        I invite you all to write a list of all the statements throughout history that were Common Sense at the time, but were flat wrong.
        Do it.
        It’s a hoot.

  7. wilf wilford says:

    Such critical discussion is great to see.

    Last year a colleague and I stumbled across some seemingly obscure work by one of the world’s finest whole-systems guys from the University of Manitoba called Vaclav Smil . From memory Smil was doing some deep analysis on the stocks, flows and impacts of meat intensive diets in various countries. His work exposed some powerful info about the changes in mammalian zoomass over the last 10,000 years. The story goes something like this:

    ——10,000 years ago homo sapiens and our domestic animals (for food, beasts of burden and companionship) comprised less than 0.01% of the earth’s mammalian zoomass. Around the start of the industrial revolution this had increased to between 10-12%. Now, humanity and our domestic animals comprise somewhere between 96-98% of all of the mammalian zoomass on this planet——

    Stark, sobering and scary!

    Now consider all of the energy and resources required to maintain this dynamic! Then ask yourselves how significantly the risks increase as we hurtle to 9.2billion? Add to this the latest planetary overshoot figures from the Global Footprint Network (In 2010 we used 1.44 planets worth of eco-systems services).

    While we are at it, why not have a look at the planetary Nitrogen system so that we can get a more complete picture of the inherent risks in this population Ponzi scheme. The magnificent rise in agricultural productivity has in part been attributed to the Haber – Bosch process (the nitrogen fixation reaction of nitrogen gas and hydrogen gas, over an enriched iron or ruthenium catalyst, which is used to industrially produce ammonia which is then used to make nitrogenous fertiliser). Natural gas whilst more plentiful than the other fossil fuels is still a finite resource. I read some stats a while ago showing that without industrial scale fossil fuel augmentation the natural nitogen fixing process (root nodules on plants etc) could only build about 4billion human bodies (and that doesn’t include all of our domesticated animals). Hmm! Interesting!

    At local, national and even continental scales the picture often looks far more benign. It is only when we take a planetary view that the serious consequences of our success as a species becomes apparent.

    Another of my colleagues has been in contact with Smil and apparently he is going back to sharpen up the research. Even if his numbers are of medium fidelity we are in for some major civilisational shocks…and I haven’t even mentioned the dark spectre of spreading warfare. Nah! let’s keep it light…I’m off for a Fosters and meat pie.



    • I hadn’t heard that. I have eaten a very low meat diet for many years (a little fish, practically no meat, except as flavoring in soups, etc.) As far as I can tell, the results have been beneficial. My health is much above average. Cutting way back on the number of meat animals would seem to make a lot of sense.

  8. RobM says:

    History teaches that all bubbles eventually pop and when they do they revert to below their nominal level. We can thus be pretty sure that population will drop below 1 billion this century. I’ve been studying the bubbles that Rome and China achieved without fossil energy 2000 years ago and it seems likely that we will retrace to their post bubble levels which I think were somewhere around 100 million.

  9. Gary Peters says:

    Thanks for the comments. Most of them focus on fertility, but I think mortality will be more of an issue as oil prices go higher, especially in large urban agglomerations in poor countries where people must buy food and have no opportunity to grow their own.

    As Gail noted, fertility may go even lower in Japan, though it is already very low and Japan already faces a long-term decline in population. On the other hand fertility in much of the Middle East and North Africa is quite high, though uncertainty might move it down a bit.

    Economists believe that in the future economic growth will bring fertility down even in today’s poor countries, but that willl be far less likely as oil gets more expensive. In that case rising mortality seems more likely, unless the rich countries step in to a much larger extent than they do now to provide food. Even that would only postpone the inevitable–population growth has to stop. Worse yet, unless people are wrong about our reaching peak levels of oil extraction, it looks like population will need to decline, perhaps substantially.

    We can disregard this idea if and only if we believe that the rise in population from one billion in 1800 to 7 billion today has occurred without the help of fossil fuels. I see no reason to believe that, nor do I believe that we can sustain high levels of fossil fuels far into the future. If we do, then we’ll face ever rising CO2 emissions and increasing results from global climate change.

    I’ve argued for decades, to little avail, that we should stop population growth by controlling fertility, but I’ve had little success. China did so and voila, the Chinese Economic Miracle. The one-child policy did not “cause” the economic growth, but it certainly enabled it once Chinese leaders moved in the direction of more market oriented economics.

    • Bicycle Dave says:

      Hi Dr Peters,

      I give China a great deal of credit for actually having a population policy – the USA has no official population policy. The tacit policy is: Population growth is necessary for economic growth.

      It is interesting to note how the China policy is generally vilified in the US press – especially from the religious fundamentalist folks. This topic is totally toxic in our political sphere.

      • Gary Peters says:


        It has been estimated that if the whole world today were to adopt China’s one-child policy then by the end of this century the world’s population would be back down to where it was around 1900, i.e. somewhere around 1.6 billion. That would be a great thing for the planet!

        I agree with you that we are likely to see far more humans before anything changes. How many more and how soon change will come will be determined, I think, by what happens with oil extraction and prices in the years ahead.

        The U.S. is a perfect example of what you said about a place growing as a result of immigration. Immigrants and the children of immigrants today comprise most of this nation’s population growth.

        • Jan Steinman says:

          “The U.S. is a perfect example of what you said about a place growing as a result of immigration.”

          Although many such arguments have a hidden undercurrent of racism, it is troubling that such immigration has a disproportionate effect on the planet.

          Everytime some do-gooder movie star adopts a little brown baby from some third-world country, the human footprint on the earth goes up by about 30 person’s worth!

          Rather than view this as racist, I think it is more incumbent on people in rich countries to reduce their load, rather than criticize poor countries for all their relatively low-impact “brown babies.”

  10. Jan Steinman says:

    It’s long been claimed that the key to lower fertility is educating and empowering women. Close! That word, “empower,” speaks volumes.

    It’s long been my theory that what really drives fertility is access to energy, and that empowering women is simply that — giving them access to energy.

    This implies that as energy declines, birth rates will return to historic levels. This is also reflected in the WORLD3 models used by the Club of Rome to predict the end of growth.

    • Also, availability of pension programs and government “social security” plans influence the decision of families not to have children. It is very difficult to keep these up with declining energy availability, meaning that people will again have to provide for their own retirement through living children. This also is likely to contribute to a rising number of children per woman.

      • Jan Steinman says:

        Yes, for hundreds of thousands of years, children have been both a slave labour force and a retirement plan.

        My plan was to put all my money into productive farmland, structured as a co-op, and providing training and a living situation for younger people who can earn “sweat equity” in the co-op. That way, I still get to feel smug about having no children and being off the economy, without having to worry too much about what will happen when I’m too old to work. At least, that’s the plan… 🙂

      • Bicycle Dave says:

        Hi Gail,

        people will again have to provide for their own retirement through living children. This also is likely to contribute to a rising number of children per woman.

        As I recall, many moons ago, you made a similar comment in the context of something like: predicting future population trends is very difficult and generally increasing poverty might well cause an increase in birthrate – at least until collapse is well underway. I thought that was a valid observation – and I still do.

        Although I think this is a very good essay on population growth, it also grates on my sensibility of this issue. From Wiki:

        “Population growth is determined by four factors, births(B), deaths(D), immigrants(I), and emigrants(E). Using a formula expressed as ∆P≡B-D+I-E In other words, the population growth of a period can be calculated in two parts, natural growth of population (B-D) and mechanical growth of population (I-E),in which mechanical growth of population is mainly affected by social factors, e.g. the advanced economies are growing faster while the backward economies are growing slowly even with negative growth.”

        As you suggest, predicting population trends is very risky business. However, I will suggest that Dr. Peter’s statement does adequately not consider all the possibilities:

        I doubt that Earth will see the 9.15 billion people that the United Nations projected in its medium variant for 2050; even the 7.96 billion in its low variant seems highly unlikely.

        I’ve observed two behaviors:

        1. People in affluent countries, who lower their birth rates, very often welcome immigrants from high birth rate countries in order to have a labor supply for menial work (and sometimes very high skill level work). This grows their overall population rate despite lower birth rates.
        2. People in very poor countries will endure deplorable living conditions while continuing with high birth rates – something that became evident to me while traveling in India and Mexico. Often, the children of these countries are the ones who immigrate to the affluent countries to send money home to their family.

        The combined effect of these two behaviors is continued global population growth despite the obvious irrationality of doing so. This could go on for some time yet.

        Although any number of scenarios could cause a population decline from this day forward (nuclear war, asteroid, KSA revolt cutting off oil, etc) it is also possible that we will see a “muddle through” scenario that results in a 9B global population. This, of course, will probably result in a more serious collapse scenario as energy supplies ultimately deplete to an unsustainable level.

        • Gary Peters says:


          I’m not really trying to “predict” future population growth. Rather, I’m trying to add back a variable that has been disregarded or assumed in way in both the first and second demographic transition models–mortality.

          The formula that you cited is correct but tells us nothing of why we see what we see. Let’s start with the simplest case–the world. World population growth equals births minus deaths, period (unless you accept the notion of aliens regularly moving here).

          The primary variable that has generated sustained and unparalleled population growth over the last couple of centuries has not been increases in birth rates, it has been decreases in death rates. The latter have been substantial and widely distributed and can be directly related, I believe, to a host of advances that have come with the industrial revolution with its rapid exploitation and utilization of fossil fuels.

          Such advances include better food supplies, better distribution of food, improved sanitation, advances in drugs and medical care, and a host of other things that have brought death rates down.

          Later, starting in western Europe, birth rates started to come down as well, leading to development of the first demographic transition, which proposed that with economic growth birth rates would gradually decline downward to meet death rates at a low level, resulting in demographic stability.

          By the 1980s it became apparent that in many rich countries birth rates were dropping below death rates, so populations were actually starting to decline, unless immigration could make up the difference. This led to the second demographic transition, which, like the first, assumed that mortality would continue to decline but fertility would decline even further.

          Notice, Dave, that in both cases fertility is the variable of interest, not mortality. My point, perhaps not clearly made, is that given what we can see about the future of fossil fuels, a third demographic transition model may be needed, one that considers rising mortality.

          Keep in mind that it has not been rising fertility but falling mortality that has generated unprecedented population growth. As fossil fuels get more expensive then it seems possible, if not likely, that the world will not be able to maintain low mortality everywhere. If death rates start to rise, then population growth will slow, stop, or reverse.

          I hope this helps you think a bit more about our current population predicament.

        • Bicycle Dave says:

          Hi Dr. Peters,

          World population growth equals births minus deaths

          Yes, agreed. Perhaps I over react because so many others point to declining birth rates in specific countries – while, in fact, the population growth rate in those same countries is still increasing due to immigration.

          I’m sure you are right that longevity will decrease and eventually lead to global population decrease. My bit of pessimism is that we could still see a substantial population growth before the decline starts – and this could make matters worse.

          Either way, in the end, I suspect your thinking is correct. It is interesting to listen to those folks (some on TOD for example) who sincerely believe we could have 20B happy humans just by implementing more equitable food distribution practices.

        • I guess I have a harder time seeing a muddle through scenario than you do. Our financial system is fragile, and if it goes, I am afraid it will take with it a lot of international trade, and greatly reduce capital investment of all sorts–oil extraction, building roads and cars, electricity production. I am afraid we are in for a bad downward spiral.

          I know my own grandparents came to this country when they could not make a living in Norway, because there were too many children to divide up the family farm /business among them. So we have a long tradition of people moving from over-populated countries to less over-populated countries. At a minimum, it would be nice if birth control were readily available (and free) everywhere, so that women could have a choice regarding how many children they have.

        • Murray L says:

          You mention the real possibility of a downward spiral where international trade and capital investment of all sorts might be in doubt. What about the possibility that this economic collapse could lead to difficulty in producing and distributing contraception? For instance, given that the pill relies heavily on the complex pharmaceutical industry, do you think that the pill might be more difficult to access in the future?
          If contraception does become more difficult to access, would this affect your view of the role of fertility in the third demographic transition? How important do you think contraception has been in the previous two demographic transitions? Of course, if the future global population is resource constrained, then contraception availability will not be able to affect population totals. But, unfortunately, could it mean that more people would be born, and thus, a likely higher mortality rate?

          • I think contraception availability could definitely make a difference. I know back before “the pill” was invented, US birth rates were much higher than they are now. After the fact abortion will be used too, but it can be dangerous, if done outside of a medical setting.

      • Josh P says:

        I thought I was the only one who believed that about pensions and social security! Governments promise a system to take care of folks in old age, and people relying on the system have fewer kids. Isn’t this true of basically every place where pensions and social security or similar systems exist, since the times they were implemented, and not true of essentially anywhere else?

        • I have seen observations to this effect before, but I don’t have references. It certainly would make sense. I know one of the reasons why abortion of female babies is so high in China is because people see male babies as being able to help them in retirement, but female children are not very helpful.

          If you look at the Old Testament, not having a male child was considered very bad–even a reason for divorce. I think much of this had to do with being able to help older relatives in their later years.

  11. Andrew Polacek says:

    Not to get overtly political here, but there are clearly negative repercussions from our current welfare policies in relation to population as well. Given the scenario lied out herein, which I agree with, you have two classes of people: the educated who realize they themselves can not support a family and do not expect or qualify for government assistance to do so and those who are less educated who are either so ignorant that they don’t realize they can’t afford to support a family or are aware of government programs providing a support structure for them to have as many kids as possible (which they apparently do according to statistics). Just another example of how market interference skews incentives and makes the world a more screwed up place than it already is. As a Californian, I can tell you that there is evidence of this two class structure of population growth everywhere in this State. I guess we do indeed lead the nation….in good and bad.

  12. As I look around, it seems like I see more and more signs of a demographic transition. Quite a few young people are still living with their parents, several years after they finish school, because they earn so little, they don’t see a chance of getting married and starting their own families. There are also quite a few households around that consist of single men or single women sharing an apartment or house. Some of this may relate to sexual preference, but quite a bit of it seems to relate to not having the funds to settle down and start a family.

    It seems like all the problems in Japan are going to lead to an even lower birth rate there. I wonder too, if the problems in North Africa and the Middle East will translate to lower birth rates.

    • schoff says:

      Great Article, and I agree with your post. There appear to be signs of this already in the US. I read an academic paper some years ago about household formation in the US starting in the colonial period which said “surviving children” would leave home and goto work in another household (not their parent’s) through their mid-20’s to acquire the financial assets to create their own household. This is prior to coal, but had the advantage of the frontier expansion.

      Cheap/free/subsidized food certainly supports high birth rates, so to the extent that this goes away during the ME problems I would say yes. Unfortunately the local political machines (even if single party) recognize that revolution is connected to hunger, so you are probably waiting for secondary affects like dis-investment in electric power to eventually affect population and food. Pakistan comes to mind.

      Forgive me for my pessimism most days I feel like we’re acting like
      bacteria in a petri dish, the “bloom” is about over, you know what comes

    • fishsnorkel says:

      I assume you’re aware of Virginia Deane Abernethy’s Fertility Opportunity Hypothesis, which suggests, rather blasphemically, that humans regulate their fertility in response to perceptions about their relative economic future (just like lots of other animals); i.e. young adults in the UK still living at home and with no prospect of buying a house don’t have children because they have little chance of raising kids capable of competing well in western society.

      It’s all about r and K strtegists. Demographers tend to treat humans as uniform quantities, but variety is everywhere and fertility is no different. R-strategists at one end and K strategists at the other and, despite deomographic beliefs suggesting humans don’t compete with each other, humans compete with each other and which strategy is most successful at any one time depends upon the prevailing conditions of life (Lars Witting calls this malthusian relativity). In high density populations, where interactive quality needs to be high (children need to be highly educated etc. to have the best chance in life), K-strategists (high investers in low numbers of children) are favoured, as will be well demonstrated when competition between humans intensifies as a result of a diminishing energy supply (tribal peoples may actually be the best placed because they already know how to survive without oil).

      • Jerry McManus says:


        Economists are fond of pointing out the correlation between economic growth and the demographic transition, however correlation does not always equal causation.

        I’ve always thought that an equally strong correlation could be made between urban density(rich or poor) and lower fertility rates. The “Fertility Opportunity Hypothesis” would seem to support that view.

        On an unrelated note, another curve worth watching is the percentage of work performed by muscle vs. machine. Before the fossil fuel party it was something like 90% or more muscle power, mostly draft animals, but let’s not forget some of it was human slavery as well. Now it is something like 10% or less muscle power.

        Adapting to a world that is forced to return to 90% muscle power will be painful to say the least.

        • Gary Peters says:


          You are right. It is almost universally try that urban populations have lower fertility than rural ones. It is also true that in the past much urbanization was driven by economic growth, but that seems less true in many poor countries today.

          Watching your variable of muscle power versus machine power is a good indicator of whether we are progressing or regressing. I think oil extraction reached a per capita peak in 1979, which doesn’t bode well for a future in which population growth continues. It seems to me that if we are hitting a “hard ceiling” with respect to energy, then we are going to be in trouble in decades ahead.

          If that is the case then you are right to suggest that it may be “painful.” Sooner or later even economists will be forced to admit that no physical system can grow indefinitely. Most economists still cannot understand that the economic system resides within Earth’s ecosystem, not the other way around. These folks seem to suffer from “physics envy.” They cannot comprehend that economic “laws” may work at one time or in one place but not in all times or all places. As a discipline, economics has grown up in an era of cheap fossil fuels. It is at least conceivable, if not inevitable, that the “laws” they developed in that era will no longer work as that era disappears.

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