Population: what’s the problem?

Apologies for the clickbait-y title. My question isn’t a rhetorical one intended to suggest that human population levels aren’t a problem. I don’t doubt they are. But it seems to me much less clear than a lot of people seem to think exactly what kind of problem they are, and what – if anything – could or should be done about it, which is what I want to aim at in this post. I raised these issues in my last post of 2017, which prompted some lively debate. But neither the post itself nor the comments under it quite nailed the issue for me, so here goes with another attempt.

1. Of proximal and underlying causation

In a recent article by the evergreen George Monbiot bemoaning plastic pollution in the oceans, the first comment under the line had this to say: “Two answers – population control and capitalism control – but no takers…not even George!”

It strikes me that this response is spot on…and also entirely misses the point. It’s spot on because although plastic pollution in the oceans is an immediate problem, it has deeper underlying causes which are summarily encapsulated by the words ‘population’ and ‘capitalism’ about as well as by any others. I think it’s a bit unfair to accuse George of not being a ‘taker’, since part of the point of his article was to suggest that self-fuelling economic growth – ‘capitalism’ by another name – is intrinsically destructive of the environment. Still, it’s surely true that without large global populations subject to the forces of capitalist commodification, the problem of plastic in the ocean would be very much less severe than it presently is.

But what is the ‘answer’ to the problem of plastic pollution, now that it’s there? Is it really population control and capitalism control? Suppose when the governments of the world met to negotiate the Montreal Protocol they’d said “the immediate problem of the ozone hole is caused by CFCs in aerosol propellants, but the underlying problem is population and capitalism. Therefore, rather than banning CFCs we propose to adopt a more holistic approach and exhort each member country to foster population control and work towards economic alternatives to capitalism”? Luckily, they didn’t, and the ozone hole is now a lot smaller than it otherwise would have been as a result.

Doubtless population and capitalism remain underlying problems, investing other issues – such as plastics in the ocean. Again, though, are population control or capitalism control the best means we have of addressing these other issues right now? Apparently, about 90% of ocean plastic pollution arises from just ten river systems in Asia and Africa, basically as a result of inadequate waste management systems and a lack of public consciousness about waste disposal in these rapidly industrialising places1. The most efficient remedy would seem to be targeting investment in waste management systems in the relevant places. It’s not a radical strategy aimed at the underlying generative factors, but it’s probably the most effective strategy aimed at the actual problem. Generally, I’m in favour of approaches that tackle the underlying nature of a problem, but sometimes it’s possible to overcomplicate things. The main problem with plastics in the ocean is plastics in the ocean.

It’s not an either/or thing, of course. Alongside strategies to reduce plastic pollution, strategies to reduce population and transcend capitalism also have their place. However, when someone like George writes an article identifying a particular issue such as this and gets the population/capitalism brush-off in response, I can’t help feeling that this is a way of relegating the problem from serious policy attention in the here and now. It would be a good thing if human population was lower than it is. But it isn’t, and it strikes me that very few of our contemporary problems are best tackled by prioritising population control as the main policy response. Certainly not plastics in the ocean.

2. Theories and causes

Nevertheless, it seems clear that high levels of human population lurk somewhere behind the numerous environmental crises of our age. But exactly how to elucidate the relationship between population and environmental impact is less obvious. In my previous post I critiqued ecological economist Herman Daly for a simplistic take on this (Daly is a fine thinker, but his subtlety seems to desert him on population matters). In a recent article, Daly said,

“Environmental impact is the product of the number of people times per capita resource use. In other words, you have two numbers multiplied by each other – which one is more important? If you hold one constant and let the other vary, you are still multiplying. It makes no sense to me to say that only one number matters”2

But, as I mentioned in my previous post, I just can’t see how Daly’s logic escapes a tautology that becomes obvious when you write his words down as an equation:

(1) Impact = Per Capita Impact x Population


(2) Impact = (Impact ÷ Population) x Population

The fact that total impact varies in direct proportion with population when it’s written as a function of impact per population is a mathematical truism, but it doesn’t tell us whether population actually does affect impact in the real world. The same is true of the I = PAT formula that’s also often invoked to characterise the relationship between impact and population. These mathematical formulae are merely a priori assertions, not empirical findings of real-world relations.

Let me take this example. In the 1960s the global whaling fleet was catching about 25,000 fin whales annually. We could take the fin whale catch as one indicator of environmental impact. Global human population was about 3.5 billion at the time, so the per capita impact of fin whale hunting was about one whale per 140,000 people. Population back then was increasing globally by about 2% per annum. So was the fin whale catch increasing by about 2% as well? No. Only a handful of nations were involved in whaling, and catch levels were determined by various factors that had little to do with global population. You just can’t write a meaningful, predictive per capita impact x population equation in this instance.You need to fit a theory to the data, not data to a theory.

Doubtless there are other issues where population level does have a more direct and independent effect – greenhouse gas emissions, for example. But we know that individual-level emissions vary between people by a factor of at least 2,000 according to life choices and circumstances, so if we’re going to insist on writing an environmental impact equation with population level as an independent variable in it, it’s going to have to be something of the form:

(3) I = p∑iv

Where I = total impact, p = total population, i = per capita impact and v is a variable factor representing these individual differences in emission levels.

The fact is, you just can’t infer from such a formula that I is going to vary directly with p.

Perhaps this is all an over-elaborate way of making the familiar point that what matters most isn’t population level itself, it’s what populations do – burning fossil fuels, clearing forests, dropping plastic in rivers and so on. Some populations do a lot more of those things than others. So generally speaking, v seems to me a more important variable to focus policy attention around than p.

3. Fertility decline

And this is particularly true because while the population debate rages on, meanwhile – unnoticed by many – global fertility is crashing at a historically unprecedented rate, as indicated in the graph below, which shows fertility rates worldwide and for the world’s five most populous countries over the last 55 years.

Source: World Development Indicators –  http://databank.worldbank.org/data/reports.aspx?source=world-development-indicatorshose

Those who say there’s inadequate attention to population control might do well to ponder the implications of this graph. In just fifty years, global fertility has more than halved, from an average 5.07 live births per woman in 1964 to 2.45 in 2015. In three of the five most populous countries of the world, fertility rates are considerably below replacement rate – and in fact this is true in about half the countries of the entire world. I would have thought that the trend shown in this graph would be widely celebrated by the anti-population lobby, but it scarcely seems to get a mention. True, population itself rather than population growth rate or fertility rate is continuing to rise for the time being as a result of the time lag between present fertility and its manifestation in future birth rates – there’s not much that can be done about that, short of mass murder or enforced childlessness. Fertility rates have to drop first before population level does, just as a car has to stop accelerating before it can start slowing. But for those who say that not enough is being done to reduce population, I wonder what realistic policy measures they believe could have been implemented over the last fifty years that could have improved on this 50% fertility decline.

It’s worth noting that not many countries apart from China have implemented explicit population control policies, and if you look at the graph you’ll see that the point at which China introduced its one child policy (1979) came after its steepest fertility decline. So it seems that on this one, the people of the world have voted with their feet…or maybe with other parts of their anatomy…and done the policymakers’ work for them. Certainly, it would have been hard to implement official population control policies globally as effective as this gigantic act of self-implementation, and perhaps unwise too – many countries are going to face significant social problems in the coming century as a result of this demographic collapse, however welcome it may be for other reasons3.

Of course, the demographic collapse doesn’t mean that our environmental and resource problems are going to magically sort themselves out. Which is another reason why the ‘problem’ isn’t really ‘population’…‘capitalism’ gets a bit closer to the mark, perhaps. The billions of people who live on just a few dollars a day certainly do have an environmental impact, but it’s really not them who are driving the drastically negative impacts in the contemporary world. However, I’d guess that the majority of them would love to live as impactful a life as the average European or North American if only they could. In that sense, globally reducing fertility rates aren’t necessarily much to celebrate.

But maybe with global population set to decline in the future, there’s less need to panic about increasing crop yields, ‘sparing’ land, intensifying agriculture and all the other components of high tech solutionism that are routinely trotted out in relation to rising human numbers and pressure on earth systems. Maybe the idea of settling in to our existing local places for the long haul at historically very high, but soon to be declining, numbers might prompt some more sober thinking about the possibilities of a more sustainable, steady-state kind of agriculture.

The reasons for the astonishing fertility decline don’t seem completely clear, but are largely to do with the demographic transition (declining birth rates following declining death rates) and ‘modernization’, generally speaking. So inasmuch as the line I take on this website is generally opposed to ‘modernization’, perhaps it’s worth musing on the implications of a small farm future for fertility rates or future population levels.

Against the notion that peasant farmers always have high fertility, the evidence suggests that in situations where population pressure on land is a limiting factor (which could well be the case for a lower energy, small farm future in a country like Britain), people attempt to keep their fertility levels low4. But high fertility can look like a good idea if you have no means of supporting yourself in old age and/or you or your children are unlikely to be able to attain a secure livelihood. So if I were responsible for social policy in a resource-constrained country of small farmers in the future, I think I’d prioritise primary health care for mothers and infants, social care for the elderly, and educational/job creating opportunities for young people. Doubtless this would pose many challenges, but on the upside they’re all people-intensive rather than energy or capital intensive projects, and that’s where the true wealth of human societies lies.

I’m in no position myself to lecture anyone about the evils of human fertility but here’s a final thought: there’s something quite odd historically about societies that deem having children to be a bad or irresponsible choice on the grounds of environmental impact, without attending more directly to the nature of the impacts themselves. I have no idea how that’ll pan out, since there are so few historical precedents. My guess is that while other countries will try to ape the high-consumption low-fertility western style, not many will succeed and in the longer term that high consumption low fertility style will go the same way as other weird religious cults of the kind that emphasise celibacy and service to some jealous and demanding god. People will get old, the freezers containing the corpses of the transhumanists will run out of juice, the trinkets will lose their lustre, and ultimately our societies will be replaced by ones that are better able to farm and function at sustainable levels of energy use by attending more to v and not so much to p in equation (3) above.


  1. Schmidt, Christian et al. 2017. Export of plastic debris by rivers into the sea. Environmental Science & Technology. 51, 21: 12246-53.
  2. Daly, Herman. 2018. Ecologies of scale. New Left Review. 109: 81-104. p.93
  3. Morgan, Philip. 2003. Is low fertility a 21st century crisis? Demography. 40, 4: 589-603. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2849155/
  4. Netting, Robert. 1993. Smallholders, Householders: Farm Families and the Ecology of Intensive, Sustainable Agriculture. Stanford UP.

91 thoughts on “Population: what’s the problem?

  1. ” I = p∑iv

    [… ]Perhaps this is all an over-elaborate way of making the familiar point that what matters most isn’t population level itself, it’s what populations do ”

    Yes, but somehow putting it as a formula makes it more plausible! (I’m only half joking …)

  2. I’ve had to point out that birth rates are decreasing quite remarkably to a number of people over the last few years.
    Many seemed a little disappointed.

    The disappointment of doomers who’d always included the poor down south in the collective guilt trip as being the ones who didn’t have enough money do consume like they did, but were at least equally guilty by breeding like rabbits.

    “Maybe the idea of settling in to our existing local places for the long haul at historically very high, but soon to be declining, numbers might prompt some more sober thinking about the possibilities of a more sustainable, steady-state kind of agriculture.”

    A statement sure to cause pure horror.
    Settling in, being patient, not wallowing in the mud of gloriously filthy ends to all of humanity. Welcoming uninvited strangers instead of paying strangers to welcome oneself wherever in the world one chooses.

  3. high fertility can look like a good idea if you have no means of supporting yourself in old age and/or you or your children are unlikely to be able to attain a secure livelihood

    I think something like this should have been at the top of this section!

    People — professional demographers and their TLA NGOs, especially — always equate lower fertility with women’s education. But correlation is not causation, and I submit that women’s education is merely a side-effect of affluence, which itself is a side-effect of access to energy.

    High fecundity has traditionally been both a retirement plan and a slave labour force. I fear that, as energy goes into decline, birth rates will again increase, as more people are once again forced to breed their retirement plan and labour force. (In fact, increasing birthrate is even seen in the output of the ancient WORLD3 model that led to the publication of Limits To Growth.)

    Can a low-energy civilization afford elder care and labour-intensive, non-mechanized food production? We’re about to find out! Coming soon, to a civilization near you!

    • There definitely are studies that suggest a causal link between education and fertility rate, Jan. The micro studies mentioned at this link…


      …are especially interesting. Here’s a brief excerpt:

      “Micro studies are not aggregating the measured aspects on the societal level – such as the country level – and instead allow to track the circumstances and behaviors of individuals. This is particularly helpful in our question because it is so difficult to disentangle the causal relationship between fertility and education – while better education is possibly related to lower fertility, it would also be reasonable to expect that the other way around, lower fertility increases the opportunities for women to receive better education and that this is the reason we see a correlation.

      “Micro studies can shed light on these seemingly intractable problem, particularly when they are set up as randomized evaluations. Duflo, Kremer, and Dupas (2015)10 conducted such a large randomized evaluation in western Kenya over a period of 7 years in which they found that subsidies to education decreased the rate of pregnancies in adolescent girls. Because we can study the effect of the policy intervention in this evaluation, we can see that the relation in question is not driven by an impact of the number of children on the education of women.”

      • There definitely are studies that suggest a causal [emphasis mine] link…

        while the info you quoted says:

        this is the reason we see a correlation. [emphasis mine]

        The material you quoted does not mention whether other life-style factors were considered and either ruled out or corrected for. That “adolescent girls” who received “subsidies to education” had decreased pregnancy is no more a causal link than if the increased education these girls received enabled them to gain employment, and thus, affluence, that would have otherwise been denied them.

        Please forgive that I don’t have time to go over the link in detail, but if this research corrects for other economic factors associated with education, that would be one mark against my theory.

        A big influence for me is Schooling the World, the White Man’s Last Burden which does not explicitly refute the “educating women reduces fecundity” claim, but does strongly suggest that education causes a whole raft of changes (including increased affluence and access to energy) that could be affecting fecundity.

        Cart? Horse? Difficult to say with certainty. But I’d be willing to bet that if you didn’t “educate women,” but only gave them an energy-rich, western life-style, their fecundity would go down.

        • I tend to agree with Jan on this. I think it is the same with education and economic growth. Schooling and formal education is something that grows when people can afford it – not the other way round. Most countries experience their highest econoimic growth rates (as well as population growth) when education is still low.

  4. Right on, Chris.

    Expanding a bit on something you wrote:
    ‘…a result of inadequate waste management systems and a lack of public consciousness about waste disposal in these rapidly industrialising places.’

    Sometimes it’s the generation of waste itself that’s the problem, not the inadequate management of waste.

    A friend spent time on a very remote Pacific island, and he recounted how disposable diapers are now very popular with the locals. There’s also a significant demand for more cars, even though the island has maybe one paved road.Of course, used diapers and junked cars aren’t worthy of air freight or the occasional cargo ship off the island, and landfills are not compatible with small islands. There is no ‘away’ where they can be thrown, so they pile up or are abandoned. He said that occasionally a pile of used diapers gets some diesel poured on it and is burned, a terrible ‘solution’ as you can imagine.

    The supply tries to meet the demand (basic capitalism at work), but looking at the reasons why the demand is there in the first place, it’s clear that it’s not really because of overpopulation. Washable cotton diapers would dry quickly there, and bicycles seem ideal for such a small, flat island.

  5. That graph just cheers me right up!
    I can’t see how fewer humans can be a bad thing at this point, even if it puts the social system under some stress down the road. Why should we never have to suffer stress when we inflict it so thoughtlessly on every other species.
    Now you will have put me in a good mood for days at least with that graph;where exactly did it come from?

    • Down the road we’ll have to do something very specific, something people are being dissuaded from vehemently (for very specific reasons):
      Managing the population descent over the next maybe two generations (which might turn out to be a lot quicker than the long descent of civilisation itself) with an ageing population.

      Which means a population whose elderly and soon-to-be-elderly have been taught to only value muscles as tattooable real estate, expect a mechanical/electronic gadget to take over once a perceived weakness sets in, and only take pride in still being able to think, not do things after their retirement.
      I have a mother who is regularly taken aback by having no real answer to age peers’ questions about diseases and medications – she has none, takes none.

      How many of these people are present today; how many will be left once it becomes clear that the world won’t be going down in flames and that, yes, even people at age 60+ can take care of their own physical affairs very well if their skeletal muscles are cared for?

  6. The work in the UK seems to suggest that ambition acts as the most effective contraceptive.

    If you think that you will be able to achieve something in your life and obtain entry to the adult world that way then parenthood, in particular early parenthood is a less attractive offer than for those who see life offering nothing more than a zero hours contract shelf stacking

  7. I think you are too quick to denigrate I=PAT. Impact = Population X Affluence X Technology is simplistic and it’s terms are not independent, but it does give one a broad-brush look at the main factors in human environmental impact. Ecomodernists want to concentrate on the T, degrowthers want to concentrate on the A, but it is also true that increasing P makes it more and more important to concentrate on the other terms, especially affluence. That’s why everyone worries about population.

    Jevons and others have pointed out the tendency of gains in technology to cause a rebound effect due to price incentives, the effect of which is to allow people to acquire increasing affluence as the efficiency of producing and distributing goods increases. So if we assume that increasing efficiency (decreasing the T value) automatically tends to increase A, then we can simplify the most-realistic version of the formula to I=PA (too bad for the ecomodernists).

    This means that if impact is too great and population cannot be reduced, then affluence per person must be reduced. Arguments as to how the affluence should be distributed have little relevance to the issue because redistribution, while it certainly affects how fair and just the world might be, really doesn’t affect overall total affluence.

    Those who think that a world of more equal affluence will eventually decrease population via the demographic transition tend to forget about the first part of the transition, the transition from abject poverty to minimal affluence . When, as in organic societies, total affluence is proportional to the productivity of the land, population growth is very small. If lack of land means that young people cannot afford to start a marital household, they don’t get married and don’t have children. But if the resources become available (increasing affluence), then young people can afford to get married and have kids. It was increasing affluence at the beginning of the English industrial revolution that allowed an astounding rise in the population of England during the 18th and 19th centuries.

    So the troubling implication of I=PAT (or I=PA) is that if Population cannot be reduced rapidly, then Affluence must be, or else Impact on the environment remains too high. In the current situation, if population cannot be reduced, the world’s poor must remain poor and the world’s rich must become poor. Hence our predicament; nobody wants to become poor or stay poor, everyone wants to live and too many people want descendants. Impact on the environment just keeps increasing.

    The ‘good news’ is that, as Malthus and many others have pointed out, there is negative feedback between Impact and Population via increased death rates. If we don’t reduce our affluence voluntarily, nature will reduce our population involuntarily. Impact will not increase forever, but while it does the magnitude of the eventual ‘correction’ will become larger and larger and more and more horrific.

    • Thanks, Joe, for bringing in the Ehrlich equation.

      I think Paul labeled the “A” factor wrong, though. I think it is really Access to energy.

      In which case, the “T” factor deserves further consideration, as HT Odum taught us that technology is simply a manifestation of energy.

      So the factors interact. If “A” goes up, “T” can go up, which can have an impact on “P:” if electricity in a poor village means a new pumped well, women don’t need to breed little water-fetchers.

      But the implications of “A” going down are dire: “T” must also go down, if you believe Odum. This means that solar panels and wind turbines, with their exotic rare earths and global supply chains, aren’t going to be able to boost “A.” You can’t really pull yourself up by your own bootstraps.

      All this isn’t news to anyone who has looked at the WORLD3 “Business As Usual” run, as described in Limits to Growth and recently vindicated as right on track. This model shows energy decreasing and birth rate increasing, even as the death rate outpaces the increased births. This is consistent with humans returning to breeding their slave labour pool and retirement plans.

  8. Re:
    (1) Impact = Per Capita Impact x Population
    (2) Impact = (Impact ÷ Population) x Population

    I think it’s more useful to talk about ‘Average Impact’ instead of ‘Per Capita Impact’, even though they may be calculated the same way for a single population. The ‘Average Impact’ makes for better comparisons between countries and within countries. It’s easier to conceptually grasp how one’s personal consumption (or national consumption) can be above or below the average.

    A more illuminating equation would then involve a summation of group impacts, with each group having its own ‘average impact’ for comparison. The group could be a political entity, or a socioeconomic group, etc. Such an equation would give a more nuanced view than what Joe expressed as ‘In the current situation, if population cannot be reduced, the world’s poor must remain poor and the world’s rich must become poor.’

    • Well, I claim no special ability to reject the benefits of being rich (by world standards). Perhaps that’s why I lack ‘nuance’. To paraphrase Augustine, I can only say, “Lord, make me poor, just not yet”.

      • I’ll clarify that my comment isn’t about Joe, it’s about how the simplified equation, looking at a combined population, fails to distinguish the influences of specific segments of the population.

  9. Thanks for the comments. I’m too short on time to respond right now, but I’ll aim to in a day or so.

  10. I find the issues of human population pressure and resource consumption very challenging because they intersect on so many levels; biology, ecology, religion, culture, economics, and politics just to name a few. I tend to agree with people like Garrett Hardin, who was an population biologist/ecologist. His ideas on carrying capacity, waste absorption, and regeneration of resources, made good sense to me. But human population issues are never easy to solve with logic, even if they have represented one of our biggest ecological problems until recently when the urgency of climate change took the lead.

    I concluded long ago that humans will resist reproductive control right to the bitter end and I haven’t seen anything to contradict that belief. What is the current state of population and resource consumption? I like this website http://data.footprintnetwork.org/#/ and how it looks at human population and resource consumption. It’s interesting to look at the graphics and see which countries are running an ecological deficit (higher consumption that biophysical resources available). As I expected the US is running a high deficit. But if you look at other data trends https://www.footprintnetwork.org/2018/04/11/three-visualizations-of-footprint-trends-1961-2014/ you begin to appreciate the demand imposed on the world by China.

    So assuming we actually have the ability to address resource consumption (and that’s a big assumption), how do we address it? Do wealthy countries have the right to control resources and over-consume them? How do you force them to change? Should highly populated once poor Asian countries with newfound wealth be allowed to their expanding consumption at a time when the earth is in over-shoot? And if not, how do you enforce change? And what do we do about political instability in poor African and Middle Eastern countries whose birth rates are still too high and yet are suffering food and water shortages due to climate change? Do we just throw up our hands and let the pieces fall where they may since they aren’t too receptive to Western countries meddling in their affairs? Politicians in Western countries are not doing so well fighting off Nationalist takeover of our governments. Perhaps religious leaders may have more influence?

    The sad truth is that as climate change worsens we will see more more droughts, floods, and storms that negatively affect food and water resources resulting in more failed states and more migration. We haven’t begun to address what will happen when people are forced to move inland from continental coasts due to rising oceans. Population pressure is going to make all these issues more difficult to address.

    And there is little hope of rational approaches. The news media loves to focus on suffering children! Look at how the US media has focused in on “children in cages”, our government’s decision to separate children from illegal immigrant families. At the same time many Americans want to control our border, but are not willing to do what may be necessary to actually control our border. Thank God the Canadians don’t want in! They may have more to fear of migrating Americans.
    Look at any stories about Yemen, or any African country suffering from drought and starvation. The focus is always on the children. Save the children at any cost. So what do we do to provide the resources for all our children? And what do we do with our elderly who can’t take care of themselves? Can we “allow” people to die from natural causes?

    A few ideas I think have merit. I am in favor of free birth control for everyone. I am in favor of every person’s right to chose to end their life. I don’t believe in heroic actions to save unwanted children (I want to stress unwanted because if a child is wanted, we should make adoption as easy as possible. I am not in favor of heroic actions to extend the life of elderly chronically ill patients. I detest the American disease care system that profits more from chronic disease than our health.

    I believe that if we want survive we must focus not only on our own health, but more importantly on the health of our soil and the capture of rainwater. Permaculture techniques have shown us many ways to do this. As long as we keep farmland fertile and rainwater infiltrating into the ground not running off, we can will continue to provide some access to food and water (until local climate change prevents us from doing so).
    I believe humanity has gone too far into overshoot to ever believe we can “solve” population problems or resource limitations. At some point we just have to realize that we will be limited to what is at hand. So the longer we preserve natures ability to regenerate plants and soil we can provide food for our family and local community.
    As for government rules, as Will Rogers is quoted to have said “You can’t legislate morality.” No government is going to be able to help us address resource distribution. It falls on each of us to decide how we share, with whom we will share, and how we care for the resources at hand. I’m sure there will be days, weeks, months, and even years when we find our desire to help others is limited by the resources available to do so. But until those times arrive, we can still chose.

    Bottom line….the priorities are air, shelter, water, and food…3 minutes without air, 3-6 hours without shelter from exposure to excessive heat or freezing temperatures, three days without water, 30 to 300 days without food… and most people will die. (I’ve been doing lot of reading about fasting and I find it interesting that humans can go much longer without food than most people think.) Population will be reduced when we can’t meet our basic needs.

    • “No government is going to be able to help us address resource distribution.”

      That’s a curious comment, Jody: isn’t resource distribution primarily shaped by government, through laws on ownership and inheritance? (Laws which, as I ever tire of pointing out, are essentially derelict, in that they became detached, centuries ago, from the circumstances which originally gave rise to them.)

      But perhaps you meant ‘No government is going to be willing to help us address resource distribution’ – in which case you’re probably right.

      • Malcom,
        Yes, perhaps it would be more accurate to say governments are “unwilling” to redistribute resources but in reality if oligarchs (or aristocrats) control government then perhaps I am correct to say they are unwilling. The truth is most often that greed makes a person unwilling to share resources, which is why I see this as more of a moral and ethical issue than a government issue.

        History seems to show that most governments eventually privatize resources into the hands of a minority. I don’t find many examples of governments that have been able to establish and maintain egalitarian rules. It is an ideal that I don’t think ever reaches its intended goal perhaps because humans are susceptible to greed. In all likelihood the ability of any population to fairly distribute resources to everyone is the result of short term abundantly available resources and pollution sinks.

        When I look at human history and prehistory I believe the trend is that human social groupings exploited their environment and moved on as their population grew and resources were depleted. The Garden of Eden is a mythical story that encapsulates the idea of a pristine world we left behind. Perhaps this myth is a warning of what always happens. We move on and conquer new land.

        Interspersed between episodic glaciation human population rose and fell and we learned to exploit new technologies that allowed us to slowly expand our population. The recent exploitation of fossil fuels and chemicals has allowed us the largest expansion ever seen on earth. But the question always remained. How many humans can earth support?

        Human consumption and pollution are profoundly affecting other large species of life on earth and pollution is changing earth’s atmosphere, oceans, and terrestrial climate. But even during this period of abundant resource consumption, sharing is limited to a minority of the world’s human population. And its government laws that help this minority maintain their claims over resources to the detriment of the majority of humans on earth. I don’t see government as fairly distributing resources I see government as unfairly consolidating power. Small groups of people reap the benefits of government laws to maintain their monopoly and I don’t see this trend changing.

        But let’s come back to Chris’s topic. Why do we have such a difficult time controlling our reproductive rates? Why do we allow population pressure to become such a problem? Why do we believe over-consume when given the opportunity? Humans have a difficult time voluntarily controlling their appetites. Religion and philosophy more often than politics and government try to deal with moral issues. But even in their case history shows their leaders can succumb to power and greed.

        • “The truth is most often that greed makes a person unwilling to share resources, which is why I see this as more of a moral and ethical issue than a government issue.”

          I don’t see much evidence that humans are intrinsically unwilling to share, Jody. Quite the opposite, in fact; I’d say human society has evolved through us finding ways to do so relatively fairly. But arrangements that are relatively fair when they’re introduced don’t necessarily continue to be fair as circumstances change.

          Like other creatures, humans tend to take the world as they find it and are possessive of what they see as ‘theirs’. If derelict law puts control over a country’s natural resources into the hands of a small minority, those privileged people will see those resources as theirs and will try to defend their control. It may not be enlightened but I don’t see anything unnatural or reprehensible about that.

          And I don’t see how it helps to frame the problem as a moral issue, or to characterise that behaviour as greed. The fact is that any organised society has to have a system of allocating essential resources – i.e. laws of ownership – and if that system is flawed, as our current system clearly is, it will privilege some individuals at the expense of others. Treating resource allocation as a moral issue won’t lead to fairer distribution because, unless that morality is entrenched in law, it will simply empower the small minority who are prepared to disregard the preaching. In a democracy, if we don’t demand laws that allocate resources fairly, we shouldn’t be surprised or indignant that it isn’t.

          I agree with Chris that, given current trends, population is an unhelpful distraction. To me it looks like a problem that is likely to disappear naturally if we address the more immediate problems of over/mis-consumption.

          • Malcolm,
            “Like other creatures, humans tend to take the world as they find it and are possessive of what they see as ‘theirs’.”
            Definition of morals: ” a person’s standards of behavior or beliefs concerning what is and is not acceptable for them to do.”
            We don’t just take the world as we find it. We are shaped by the world we live in. Our standards of behavior or beliefs are shaped through a process of learned behaviors. Sharing is a learned behavior reinforced by positive feedback from others with whom we share. Morals frame our beliefs of what is right and wrong behavior.

            I don’t know where you live, but in the US it is very difficult to find much hope in changing derelict laws. I agree with you, I just don’t see much possibility of getting back control of our government. A failure similar to the Great Depression may be the only way.

            I agree that population control is an unhelpful distraction because I don’t think we’ve ever been able to solve it. But the number of children a family has does make a difference. Consider families in drought stricken nations, or families devastated by hurricanes, or families fleeing genocide, then the number of children becomes a very critical issue.

  11. Thanks again for the comments. I’ll essay a few responses, working my way in rough order down the comments above – except to answer Michelle’s question about the graph first. The raw data come from the World Bank’s world development indicator dataset, and were processed into the pretty graphic you see above by Small Farm Future’s very own department of data-bothering Excel geeks. Apologies for not giving the source above – now corrected.

    On fertility, affluence & energy. I find Banerjee & Duflo’s ‘Poor Economics’ a good source. I think it’s clear that although there’s a historic association between decreased fertility and increased affluence & energy use, we’re currently witnessing decreased fertility even among poor people with relatively low energy use, and there’s an independent association with female ‘empowerment’ generally, of which education is a component. Essentially, women’s ideal family size tends to be lower than men’s – perhaps for obvious reasons. In situations where women have more power to make their ideals a reality, family size tends to be lower. But poor people with smaller families don’t necessarily invest more in each child’s education because they save more for their own future. Children as a ‘retirement plan’ is a real thing. Hence my comments above about the importance of elder care.

    On children as ‘slave labour’. This is not a real thing. I think we need to give people more credit for whole-lifecourse thinking – including the better returns from more affective and egalitarian family decision-making as shown in research by the likes of Banerjee & Duflo, and Robert Netting. Nor do people in aggregate usually produce more children than they judge appropriate to resource flows in stable agrarian societies. In some labour-scarce situations people do tend to have more children. But they are not (usually) slaves.

    On the question of whether a low-energy civilization can afford elder care and labour-intensive, non-mechanized food production, the answer from past civilizations is surely a clear ‘yes’. If there’s a sense that this won’t prove possible in the future, it would be interesting to consider why. Though probably not elder care as we currently know it.

    The island resource use example from Steve strikes me as worth pondering. What is going on here? It’s not about population, and not about affluence, exactly, which is only an enabler – apparently of sub-optimal solutions. I suspect we need to be thinking about questions of status and reputation – and this is important when it comes to finding better solutions.

    On plummeting fertility – I agree with Michelle that fertility reduction is a good thing, even if it causes some social stresses. This is pretty much the conclusion of the Morgan article I cited above. However, I think it’s a good idea to take those stresses seriously and not be too dismissive of them – migration from countries with younger age distribution to older ones is a tried and tested solution, though it’s curiously out of fashion at the moment. But I don’t think plummeting fertility is necessarily all that cheering, because there are numerous ways in which low fertility can be more than cancelled out by high impact. Nevertheless, I do think people need to take this graph on board – so when Jody writes “humans will resist reproductive control right to the bitter end”, I’m not sure exactly what she means, but people are clearly controlling their reproduction nowadays in a different way to how they were doing it a generation or two ago, having many fewer children, and I think we need to incorporate this into our thinking.

    On equations and formulas – I agree with Steve on the utility of summing group impacts. That is what my suggested formula I = p∑iv does. I think the I = PAT formula is just hugely misleading and should be jettisoned. I = f(PATx) I could live with – that is, impact is some (complex) function of population, affluence, technology and other factors. But there’s clearly too much inter-correlation of the three supposedly ‘independent’ variables in the formula for it to be able to isolate any independent positive association between impact and population. And of course, it depends on the context to which it’s applied – sometimes there will be an association, in other cases not (as in my whale example), and in some cases decreased population is associated with worse environmental impact (as when, for example, depopulation of rice paddy farmscapes results in greater soil erosion and water pollution).

    On general trends – Joe gives a qualitative account of population trends alongside other factors that I find mostly plausible, but doesn’t to my mind amount to a convincing defence of the I = PAT formula. A couple of points of disagreement. First, while it’s formally true that the distribution of affluence doesn’t affect its total pool and therefore the total impact of the affluence, I don’t think that’s how it really works. If current (or past) affluence were redistributed more fairly and this distribution was persistently reproduced, the forces driving the accumulation of further affluence would be dismantled with potential long-term effects on impact. Second, I’m not sure I quite get Joe’s point about equalising distribution and poverty/fertility transitions – but I think there may be a danger of conflation here. In relation to the increase in England’s population during the industrial revolution, you could call it increased affluence, but it might be more revealing to describe it as a reduced cost of subsistence resulting from an expanded resource base in time (thanks to fossil energy) and space (thanks to colonial domination).

    I find this comment from Joe illuminating:

    “In the current situation, if population cannot be reduced, the world’s poor must remain poor and the world’s rich must become poor. Hence our predicament; nobody wants to become poor or stay poor.”

    I guess I’d say that the world’s poor will remain poor in the absence of changes to the political economy regardless of population levels, but I agree that the rich must become poorer and that nobody wants to become poor. The solution, if there is one, has to lie in the fact that there’s no quantitative definition of wealth or poverty – and what matters most to people is status or reputation, which needn’t be intrinsically related quantitatively to affluence or to environmental impact.

    On technology & energy – I don’t see the evidence for a linear relation between increased technology and increased energy use. An example in preindustrial societies would be irrigation – Smil estimates for example that human-powered water ladder treadle irrigation returned 30 times more food energy than its food cost in Qing China. The same is true of modern renewable energy technologies (not the number, the general relationship). It may be true that a lower-energy future civilisation would be unable to manufacture PV panels as efficient as contemporary ones – or to manufacture them at all – but this isn’t because of some universal truth about the impossibility of ‘bootstrapping’ affluence via technology.

    Future energy/population scenarios – I’m not as confident as some of you in foreseeing how these will play out in the future, but I’m not convinced that global human population is likely to increase again in more or less any future energy scenario. I find Michael’s point salutary. Certainly, it’s questionable to insist as the ecomodernists do in the face of all counter-arguments that technological substitution will overcome resource and energetic constraints. However, I think it’s also questionable to insist in the face of all counter-arguments that the only possible outcome long-term is a horrific steep collapse in population, energy availability and civilizational reach. If I had to plump for one or the other as the most likely future scenario I’d probably go for the latter, but there’s a lot of middle ground that’s worth exploring and shouldn’t in my opinion be dismissed a priori. So while, as I said above, I don’t think the plummeting global fertility rate should prompt anyone to celebrate too much about the possible resource or environmental consequences, I do find it a useful little factoid for unsettling some familiar assumptions.

    • ‘…summing group impacts. That is what my suggested formula I = p∑iv does.’

      I suggested a different approach for ‘summing group impacts’ because that formula (above) with total population being multiplied by the summation (instead of having group populations being part of the summation) seems faulty. It appears to be just another way of figuring an overall per capita impact to multiply by the total population. The differences between groups would then not be obvious.

    • I don’t see the evidence for a linear relation between increased technology and increased energy use.

      We should distinguish between technology that can be produced by an organic society and technology that can only be supported by non-organic resources, like fossil fuels. There are numerous technological improvements available to organic societies, like water transport vessels, different types of irrigation systems (and water lifting devices as in your example), crop rotations, water wheels, etc.

      But the demarcation between an organic society and the industrial society we have now is the the development of the fossil fueled heat engine as a substitute for muscle power for motive purposes. While it is possible for an organic society to develop a heat engine, its use would be severely limited by the limited availability of wood for fuel. Organic societies are perfectly capable of burning through and otherwise using forests up entirely without any use of wood for heat engines. Simpler heat engines have very low Carnot efficiency and even the most advanced heat engines of today waste half the heat supplied. Wood is just too valuable to an organic society to burn it for steam power.

      Smil, Cottrell, Wrigley, and others have made a convincing case that once a society’s technology turns to the use of fossil fuels for mechanical energy, the link between increased technological development and increased energy consumption is irrefutable. That’s why we now use many orders of magnitude more energy per capita than organic societies would use.

      Industrial civilization is now powered almost entirely by heat engines. While it remains to be seen whether industrial civilization can transition to being powered entirely from non-fossil sources, the prospects for our executing such a transition don’t look good.

      In sum, if an organic technology improves the efficient use of muscle power or increases the supply of fuel for those muscles, you are right that increased use of that technology doesn’t require more energy. But if the technology can only be produced by a society using heat engines, increasing development of technology means more energy use.

      • “the link between increased technological development and increased energy consumption is irrefutable”

        It may be worth clarifying some terms here. I’d say that your statement is true at the level of whole societies or of the world after the advent of industrial capitalism. But that’s largely because of the social nature of industrialism capitalism as a historic fact, not something that’s intrinsic to technology and development as a future possibility. Technological development isn’t intrinsically more energy intensive and often results in lower energy intensities. In practice, as you pointed out above, this is often cancelled out by rebound effects – though it isn’t always, and again the reasons for this are social and not technological. In other words, the concept of ‘development’ is analytically separable from the concept of ‘growth’, even though they tend to go together in capitalist societies.

        Smil points out that each energy transition is initially funded by the energy resource of the preceding energy economy (including the fossil fuel transition, initially funded by human and animal muscle power in mining). So it’s not unusual or unprecedented to be funding a transition out of fossil fuels with fossil fuels. What’s more unusual is the undoubted need for the transition to be towards a lower overall use of energy. But I don’t see any technical reason why that’s impossible. Will a transition to a renewable medial energy steady state happen? Probably not – but for social reasons. However, it seems like our best bet, so it’s the option I want to focus on. I don’t see an intrinsic reason why ‘increased technological development’ must be associated with ‘increased energy consumption’ once they’re disconnected from capitalist value-seeking – though it may depend on how you define ‘increased technological development’.

        • The definition I’ve read and like for ‘technological development’ is, “Technology is the sum of the ways in which social groups provide themselves with the material objects of their civilization.” I might add that technology can also include the methods of managing the processes that produce those material objects. “Technological development” means creating additional ways to provide material objects or refining existing ways of doing so. Technological development requires energy for the following reasons:

          Technological development requires people to do the developing. In organic societies, most people are kept busy doing farming; they have little time for research into new technologies. In fact, for people who are devoting most of their time to farming, any diversion from farm work that fails to maintain agricultural output has an almost immediate cost in the form of hunger. That is part of the reason agricultural societies tend to be conservative. People are reluctant to do anything new that might jeopardize their food supply.

          Thus, increasing the complexity of a society’s technology depends on increasing the number of people working in new technologies. The removal of larger and larger numbers of people from farm production takes a lot of energy. Their life’s needs must be supplied by other than their own efforts, which means relying on machines to do a lot of work.

          Now also consider that the people doing the development and manufacture of any new device must use additional energy to do so. The upshot is that increasing technological complexity needs energy for the subsistence of developers and also for the product of their development.

          The more complex a society’s technology becomes, the more energy needed, since more people are needed to manage the increased complexity (without being sidetracked by growing their own food) and the bounty of that increased complexity needs energy for production and maintenance too.

          The technologies we now take for granted, like semi-conductors and advanced engines, could not exist without fantastically complex supply chains that have been gradually built up by involving more and more people over long periods of time, all of which require more and more energy to keep everything functioning.

          If increased technological development does not require increased energy consumption, why, for example, weren’t the officials of the Sumerian or even Roman empires doing their communicating by telephone or telegraph? Because even if they were given some sample phones or telegraph equipment, wire and galvanic cells, together with instruction manuals in their own language, they wouldn’t be able to create a functional system; they didn’t have the energy to support the replication and management of such a sophisticated technology.

    • I don’t see the evidence for a linear relation between increased technology and increased energy use.

      We are sitting atop a cubic mile of oil. On top of that base is a pyramid. The surface of that pyramid is encrusted with smart phones, magnetic resonance imaging machines, flying police cars, and other such high-tech things.

      All of these things “evaporate” some of the oil below. It is no longer a cubic mile. It can no longer support the tech pyramid sitting upon it. The outer layer sloughs off, exposing ordinary cell phones, X-Ray machines, ordinary police cars, etc.

      Even those continue to consume the volume of oil beneath, and the outer layers of the pyramid continue to slough off, until you’re left with smoke signals, palpating to determine injuries, ox-carts, human-dug irrigation, etc. Now, the energy required can be supplied by the energy available.

      I never said “no petroleum, no technology.” Rather, HT Odum taught us that there is an appropriate level of technology for every given energy level.

      Can today’s technology “bootstrap” a certain higher level of future technology, even at a lower energy level?

      Perhaps, but I’m pessimistic. For one thing, our repository of technical knowledge is itself bootstrapped upon high-energy technology — what would a sixteenth-century monk do with a Kindle™ that was loaded with all the present world’s technological knowledge, especially after the battery ran down?

      Extrinsic knowledge requires extrinsic energy for its maintenance. This is what I think Odum had in mind with his EMERGY models; although everyone focuses on the embedded energy of artifacts, there is embedded energy in technological knowledge, as well.

      • Yes, I’d pretty much agree with all of that. But it doesn’t negate the quote you’ve taken from me at the top – essentially for the same reasons I expressed in response to Joe.

      • There is one more aspect to ‘knowledge’ that many people overlook; it takes people to ‘know’ the knowledge. Even if some bit of knowledge has been written down, it doesn’t become known unless someone has read and comprehended it recently.

        This means that even if all present knowledge were somehow preserved in a gigantic library, it would be effectively non-existent if there were not enough people to study and understand it.

        The publication of scientific and technical articles has recently leveled off at 2.3 million per year. This means that during an average adult working lifetime of 40 or so years, there would be about 100 million articles available to read. That’s a lot of knowledge, far more than one person could absorb.

        It takes millions of people and a lot of energy to do the research that underlies all that knowledge and get it published and distributed (even if by the internet, which uses about 70 tWh, 2% of all electricity, just for its server farms).

        Once energy supplies fail and populations start dropping, all of that knowledge will disappear when no one is available to read it and understand it. As you pointed out, even knowledge requires energy for its maintenance. It also requires energy for the maintenance of the brains that know it.

        • WordPress needs a “Don’t really ‘like’, but you’re right” button. 🙂

          I wish I could share Chris’s techno-optimism, which you seem a bit conflicted about, too, Chris.

          We’re about to go through a transition without parallel in all of human knowledge.

          Perhaps my semi-researched intuitive view is too simplistic, but it could be even worse than crashing back to technology that is appropriate to energy: according to Panarchy Theory, if the omega phase stretches so long that it damages the ability to recover, the next time through the Panarchy loop peaks with less connectivity and resource utilization.

          So it might be (for example) that we won’t be able to enjoy even 1920s technology on a nature-enforced 1920 energy budget — coming soon, to a civilization near you!

    • On children as ‘slave labour’. This is not a real thing.

      Perhaps I should not have used such a loaded term as “slavery.”

      Raise your hands: who grew up on a working farm?

      I did. My parents had only five children, but they had machines, and second (and third!) incomes. Their farming families, with fewer resources, had even more children.

      Agriculture is hard work, and it is only going to get harder as fossil sunlight goes away. The labour value of larger families can’t so easily be dismissed!

      We have 43 acres in our co-op. We are zoned “Agricultural Land Reserve,” which severely limits non-farm use, including habitation. We are currently allowed one “primary residence” and one “farm-worker house.” The two-dwelling limit obviously has roots in mechanized, fossil-sunlight-based labour needs.

      A University of British Columbia agroecologist did a study for us, and determined that our peak agricultural labour needs was 49 people, using labour-intensive, low-energy agricultural techniques! Where will we put them? In tents?

      In a low-energy future, the question might not be, “Where will we put them,” so much as, “Where will we get them.” Humans are intrinsically equipped to “fix” that “problem;” which, of course, introduces it’s own set of problems.

      • Well, if you’d said farming can be very hard work and sometimes there aren’t enough hands to achieve what you wish, I’d have agreed…though this does depend considerably on the way the farm is linked in to the wider economy. However, that is not the same as saying that people choose their family sizes on the basis of how much unrewarded labour they can get out of children. In farm societies, people generally appreciate that children become adults, require dowries or bridewealth, inherit land etc etc and that is part of their thinking too.

  12. Chris,
    “Essentially, women’s ideal family size tends to be lower than men’s – perhaps for obvious reasons. In situations where women have more power to make their ideals a reality, family size tends to be lower.” I think you are correct, if women had control they would have fewer births. Throughout history midwives/herbalists knew how to prevent inception and induce miscarriage, and women often had to practice these things in secret. Throughout history women have not had much reproductive control over family size.

    Why do women have children? We are programed by our hormones (the nesting urge or the ticking clock), we are indoctrinated by culture (“how may children do you have?), we are forced by patriarchal attitudes that make men feel entitled to have sex with their wife, whether she wants to or not. And when social systems fail women and children are raped, beaten, and brutalized by men. If news stories are any indication we are already seeing more women and children sold into the sex trade, refused education, and forced into becoming child brides in some countries.

    What I meant by “humans will resist reproductive control right to the bitter end” is that I don’t think most families practice family planning. And even if Western countries have done so for several decades, I think the tide is turning. How many families do you know that planned the spacing and number of children? And what did they base that number on? It usually comes down to the size we want. I don’t see people ever accepting forced reproductive control. What would people do if they were told how often to have sex, when to use birth control, or when to terminate unplanned pregnancies? Ultraconservative Repulicans in the US are opposed to family planning clinics, abortions, and public schools teaching sex education. The Catholic church still preaches against the practice of birth control, family planning, and it considers abortion a sin. Our differences over issues of sex, money, and child rearing are the three top reasons couples divorce.

    For all these reasons I believe humans oppose population control, unless it is done to someone else. We have no problem telling others how many children they should have! But we rarely think rationally about our own reproductive urges. We rarely think rationally about threats to our children. Nature has programed our hormones to think for us, and those drives are exceedingly difficult to overcome. Which is why I think the best government can do is offer free birth control and family planning education to anyone who wants it. The academic debate has not provided solutions.

    • Agreed – people don’t like being told what they ought to do, about family size or anything else. Nevertheless, family size globally has plummeted at an extraordinary rate – though that doesn’t necessarily mean that environmental impact will follow the same trend. I tend to agree with Malcolm above that this isn’t fundamentally a moral issue, and that population control in general isn’t a major priority, which is not to say that giving people more control over their fertility isn’t a good idea (though as Banerjee & Duflo show, evidence for the efficacy of this is surprisingly patchy).

  13. I think it is as interesting to study why population increased as why fertility now decreases. It appears that high fetility is linked to ecoomic expansion, one way or the other. It works both ways of course, as a big population will fuel more economic activity. But I believe that it is primarily when there is a “growth” environment that populations will grow. In many cases it is linked to the use of energy, but in some cases it can have other causes. The American colonists apparently had a very high fertility and they had unlimited lands to conquer. As Joe points out, in “organic” societies populations are normally quite stable, controlled by a number of social, cultural and biological mechanisms (late marriage, infancy, high proportion of the population in monasteries etc. etc.).

    Likewise lower population growth is associated with more mature economies that don’t grow a lot any longer.

    The collapse of societies, such as the Soviet Union, normally leads to collapse of popultion and not the opposite. Which might be an argument against the notion that people have children as insurance for their old age….And surely all those women were not suddenly better educated because of Glasnost?

    It is probably futile to try to determine cause and effect in all this. But I am quite convinced that in localized economy there will be little population growth.

    By coincidence Ugo Bardi also just wrote about population growth. https://cassandralegacy.blogspot.com/2018/07/overpopulation-problem-what.html

    • Yes, agreed – though as you say the reasons are complex and vary in different times and places. So while a post-Soviet population decline (was there one?) is unlikely to be related to increased female education, the same isn’t necessarily true of Kenya.

      One aspect of the global population rise emphasised by Danny Dorling was the globalising consequences of the contact between the Americas and the ‘Old World’ – maize and cassava going one way, wheat, bananas etc going the other. This enabled higher levels of ‘local’ productivity in many places.

      But I agree with you that you would expect less population growth in more localised societies, and more in ones that are thoroughly inter-penetrated by capitalist economic relationships. So back to ‘population and capitalism’ at the outset of my post…

      • a post-Soviet population decline (was there one?)

        According to Dmitry Orlov, yes.

        I recall reading that it wasn’t Earth-shattering, though: after having attended a class reunion, Dmitry was thumbing through his high-school yearbook of some 30 years ago, and noticed that nearly half the students in it were prematurely dead, mostly via alcohol, but an untoward number due to preventable accidents and treatable disease.

        The Soviet Union transition to the Russian Federation might be cited as an example of what the entire human species is about to go through, except that Russia still has the rest of the world’s human species to draw upon. Half of Orlov’s peers could “go away,” and the country still exports fossil sunlight and still has the power to intimidate and invade neighbouring countries.

        So the Soviet Union collapse is probably more like the peaking of US petroleum production in 1970: deadly to some, inconvenient to others, and still others got rich off it.

        But as Joe points out, in a global civilization, we won’t have any “over there” from which to draw technological and intellectual resources from, once a global civilization collapse is underway.

        • Yes, a quick look at the figures suggests that Russia’s population declined from 149 million in 1992 to 142 million in 2010, before starting to build again – possibly much to do with alcohol-related decreasing male life expectancy.

          Not sure I agree that there will be no ‘over there’ in a global civilizational collapse. In fact, possibly the opposite – there’s an awful lot of policing of geographical, material and intellectual boundaries nowadays that I can’t see surviving a collapse scenario. And near where I live there’s a trackway built in 3800 BC where a dagger was found made of jade from Italy…

          • Not sure I agree that there will be no ‘over there’ in a global civilizational collapse.

            I certainly can’t disagree with your logic, but I was thinking more along the lines of “a falling tide sinks all boats.”

            A “dagger… made of jade from Italy” is still a stone-age tool. I don’t think all trade will cease; it just won’t be for smart phones — or wind turbines or solar panels.

            One thing nice about civilization for the post-civilization survivors is that a lot of materials have already been distributed. We can continue to fashion hoes and shovels for a long time here on the west coast of North America, while being thousands of kilometres from the nearest iron mine.

  14. Well, it’s nice to be called a techno-optimist. I more commonly find myself dismissed as an anti-technological pessimist 

    I find much to agree with in Joe’s comments, but I’d caution against too dualistic a reading of energy and technology futures: either full steam ahead with fossil-fuelled civilization or an ‘organic’ society comprised mostly of farmers scratching a bare subsistence, ever-stalked by the threat of famine. There’s been plenty of technical innovation in agriculture that’s increased yields and surpluses or decreased labour throughout the history of agriculture, including its pre-industrial or pre-fossil fuel history. I don’t consider ‘technological development’ to be the unique preserve of cadres of technical specialists who can only exist in high-energy societies of mass industrial production/consumption. In fact, the issue of mass consumption is worth pondering – there have been numerous sophisticated, surplus-generating civilizations, but none geared to the mass production of consumer artefacts prior to modernity. The prospect of turning contemporary civilization away from a mass production/consumption approach is intriguing.

    I agree that there’s been a generally positive association between technological development and energy use historically in world or world-region history. But that’s not quite the same thing as saying that technological development always implies increased energy use.

    To imply that the Sumerians or Romans should have had the telegraph if increased technological development doesn’t require increased energy consumption begs an awful lot of questions which I don’t think I can explore here, except just briefly by broaching another couple of questions. Coal was being used industrially in China 2,000 years ago, before anywhere else, to produce iron. So why wasn’t space flight first developed in China centuries ago? Europe rose to global economic dominance by harnessing the power of wind for transoceanic sailing, but this was also available to people everywhere else – why didn’t China colonise America or Europe, or America colonise Europe or China? I think it’s useful to think of ‘technology’ in terms of social connections between people, whether benign or belligerent. It’s not just about quantitative energy capture. And as Joe points out, part of that is about shared human knowledges…which only get shared if people think they’re worth sharing for a reason – a reason which I don’t think can be adequately explained in terms of increased energy capture, though that might be the result.

    I think there’s a danger here of falling into a too technically deterministic view of modernity, which is itself a common modernist idea – that modernity is driven by energy capture, that it’s course of development was in some sense natural or a given, that it’s produced a form of society that everyone past and present would recognise as inherently desirable, and that what preceded it was unquestionably awful. I don’t subscribe to any of that. In particular, I think it’s a good idea to interrogate the idea of ‘subsistence’ as in ‘subsistence farmer’. Is it possible to be a ‘subsistence farmer’ who is happy and thriving? You wouldn’t think so from the way the term is generally used nowadays, but my answer to that is yes it’s possible, though not a given.

    True techno-optimists often ridicule the notion that agriculture should be less energy-intensive or more labour-intensive on the basis that it’s some kind of primitivist fantasy. I find that unpersuasive, but nor am I persuaded by the notion that without fossil fuels the best hope for humanity is bare existence. However, that’s not to say that the path ahead looks easy or conflict-free to me. It certainly doesn’t.

    • I definitely agree that subsistence agriculture can be a perfectly acceptable, even joyous way to live. There is always the danger of too much pressure on the land, but given adequate land, there is no reason why most places in the world couldn’t provide a comfortable living from subsistence farming and a little trade with the neighbors.

      Even the Inuit (certainly not subsistence farmers), who lived in about the toughest environment anyone could imagine, managed to keep their culture going for thousands of years. They presumably liked their life well enough not to abandon it. Compared to Inuit life, subsistence farming seems like a cakewalk.

      I was wrong to bring up hypothetical technologies of past civilizations. It is impossible to prove those negatives, meaning that just because a technology didn’t develop, is no proof that it couldn’t have. It just seems intuitively obvious to me that there is a good energy-related reason why ancient civilizations didn’t have a lot of the sophisticated technology developed in the past few hundred years of dramatic growth in energy production and consumption. I keep my eye out for the definitive publication covering the energy-technology nexus, but I have yet to see it. I would welcome any suggestions.

      As to whether there will be a sweet-spot compromise between our high-tech, high-energy civilization and a subsistence society, I can only speculate that it won’t happen, that the slippery slope of descent will be steep and end at the very bottom. We will of course find out, most likely in this century, so for those who don’t like speculation, they are certainly welcome to wait for definitive evidence.

      But I still think it prudent to prepare for the worst of outcomes, not the ones we hope to see, because if we depend on something that doesn’t happen, we find ourselves in a much more dangerous situation. Those who ignore the possibility of status quo failure and blithely continue depending on it for everything they need are in the biggest danger of all.

      There is so much possible doom ahead of us as resource depletion and climate change start to really bite, from nuclear warfare, mass starvation, pandemic or any other horseman one can think of, I just wonder why everyone isn’t a doomer-prepper like me. Maybe people aren’t as optimistic as I am, thinking as I do that there is still a chance of living through a civilization collapsing into chaos if enough is done in advance to prepare for it. Maybe they don’t think about it at all.

      • I keep my eye out for the definitive publication covering the energy-technology nexus, but I have yet to see it. I would welcome any suggestions.

        I wish I could “definitively” help you! I would like to have my hands on such a paper, as well.

        If I had more time (should be out mending fences right now) I would start scouring the works of HT Odum. I have it stuck in my head that he painted the picture so clear for me, but I can’t really pin it down.

        For a while, his daughter, Mary, seemed to be carrying the torch, blogging about her father’s work, but that blog seems somewhat stagnant now.

        When you find that definitive paper, I sure would like a pointer to it!

  15. Here’s an interesting news brief: http://www.healthdata.org/news-release/nearly-one-third-world%E2%80%99s-population-obese-or-overweight-new-data-show

    “Today, 2.1 billion people – nearly 30% of the world’s population – are either obese or overweight, according to a new, first-of-its kind analysis of trend data from 188 countries. The rise in global obesity rates over the last three decades has been substantial and widespread, presenting a major public health epidemic in both the developed and the developing world.
    The rise in obesity among children is especially troubling in so many low- and middle-income countries,” said Marie Ng, Assistant Professor of Global Health at IHME and the paper’s lead author. “We know that there are severe downstream health effects from childhood obesity, including cardiovascular disease, diabetes, and many cancers. We need to be thinking now about how to turn this trend around.”

    Obesity also affects fertility. When we think about a world of declining fossil fuel, where we need more people to perform manual labor or ride bikes for transportation, it will be interesting to see what happens to our current large population of people suffering from chronic disease including asthma and autism. I could see a significant decline in population due to diseases that make such a lifestyle impossible. On the other hand, physical labor and less sugary food will help reduce or heal the problem.

    • I’d add bones, especially feet. You can try working, carrying things, with a hallux (which seems as common as the common cold, especially in women) and knees wasted away by wearing heels (of any sort), but you won’t get very far. I see barefoot shoe injunctions in our future.

      • Michael,
        Yes, sound feet and backs are critical if we are going to do any manual labor for any length of time. I imagine high heeled shoes will the first thing women give up. I often wonder why few women equate high heal shoes with the practice with foot binding in China. A big sacrifice just to have really tiny feet!
        Speaking of carrying loads, have you ever tried carrying a load balanced on your head? It is surprisingly easier than carrying it in front of you or behind. When we need to do something repeatedly we often learn better ways of doing it.

        • I’ve not carried anything on my head for any sort of distance, no – still, that might be one way to get even more weird looks 🙂
          I’ll be ordering a pack frame in the near future, and maybe switch to wearing (black) overalls alongside it during my day job. That’ll teach them!

  16. Thanks for the further comments. I agree with Joe that there’s a good case for preparing for the worst – and that it’s surprising how little serious attention our society pays to the problems it’s creating for itself. However, there’s a danger of getting sidetracked into arguing about how bad ‘the worst’ will be and therefore how more or less futile various mitigation possibilities are – so I guess on this site I prefer to focus on trends and mitigation possibilities that seem to me worth reckoning with.

    To add to Jody’s figure, depending on definitions there’s also possibly as many as 2.5 billion people who are undernourished – so that means about 60% of the world’s population is malnourished, which doesn’t say a lot for contemporary culture.

    I’m not sure that there ever is a ‘definitive’ publication on anything – though Vaclav Smil’s ‘Energy & Civilization’ that I discussed on here recently does a pretty good job I think.

    • I prefer to focus on trends and mitigation possibilities that seem to me worth reckoning with.


      The question then becomes how to sort between the mitigation efforts that will likely be effective and those that will be futile. I like the focus of SFF because I think small farms are going to be one of the few mitigation strategies that will actually succeed in keeping people alive once the global market economy fails.

      The trick we haven’t yet learned is the best way of rapidly expanding the number of small farms in the face of economic forces that want to destroy them with industrial agriculture. My efforts have been to promote the idea of small farms as ‘lifeboats’, whereas others are trying to tackle industrial agriculture head on.

      I just think that appealing to some action that people can do for themselves and their family, like becoming a small farmer, is going to be more effective that attempting to stem the tide of urbanization and the industrial agriculture it requires. One of the considerations people will have to make is to which one of those strategies (or others) they can devote their time and energy.

      I think time is too short to reform capitalism, urbanism and industrial agriculture, much less replace them with fanciful ecomodernist panaceas like automated luxury communism. I could be wrong; we could have many decades or centuries to sort out our predicaments, but I’m taking the safer route and going straight to creating a small farm for my family. I’m still looking for the best way to encourage others to do the same. I’m definitely not wringing my hands in despair or encouraging others to do so.

      In the meantime, I think that warnings of dire consequences ahead are appropriate, though I’ll try to be less of a mono-maniac about it. Perhaps one of those warnings will motivate some folks will get off the fence and onto their own land.

  17. SOOOOOO much here to digest, far too much of course.

    I have to say that population became one of my first major entry points into ecology & political ecology, and the people I’ve worked with and been mentored by (John Vandermeer, Ivette Perfecto, Doug Boucher, the late Dick Levins, and many other colleagues) have spent not-insignificant amounts of time debunking population as a simple factor in “environmental impact” and more generally. I essentially agree with Chris here with very little reservation.

    I’m not eager to dive back in to this hoary debate (as I’ve previously called it – https://beginningtoendhunger.com/2015/05/13/against-population-essentialism-redux/), though I’m often compelled by Paul Robbins’s pithy take that “Population is too important to be left to the Malthusians.” I’d highlight important pieces such as Amartya Sen’s “Population: Delusion and reality” (https://student.cc.uoc.gr/uploadFiles/1116-%CE%A6%CE%99%CE%9B.105%CE%92/Sen%20popullation%5B1%5D.pdf) which, I have to say, to my mind is still one of the more logically authoritative pieces and includes an important archaeology of some of the origins of the idea that we cannot address the relevant problems with reasoned human action (which some of the previous commenters echoed).

    Further key pieces are de Sherbinin et al.’s masterful “Population and environment” (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2792934/). Their analysis includes both nuance and forthrightness: “…as in other areas, the relationship between population dynamics and water resources is complex. At the aggregate level, other things being equal, population growth most assuredly does reduce per capita water availability. It is in this light that the Global International Waters Assessment listed population growth first in a series of root causes of the “global water crisis” (89). Yet there is more to population change than growth alone, and rarely are other factors equal, so the specific impacts of population dynamics on water often come down to ***a complex array of place-specific factors that relate to economic and climatic changes, agricultural and industrial technologies, sewage treatment, and institutional mechanisms, to name but a few.***”

    The last sentence (to which I’ve added asterisks) is perhaps paramount: even while we can point to big factors like technology, population numbers and density, affulence, education, women’s empowerment, the way these play out, and must be addressed, are often place-specific, making the abstract worrying of researchers and activists sometimes a bit… excessively abstract. That is, no amount of chiding or analytical forcefulness is likely to manifest as the needed changes on the ground; the problems go beyond our attitudes and into the messy policy details that are hard to dictate and design at grand scales. (Though focusing more on redistributional issues, power, gender relations, and international economic inequalities seem clear to me to be *more important and likely to be effective*, if you will, than focusing on population per se, even with all the complexities.)

    If I might end my overlong comment with an excerpt from my recent book (see BeginningToEndHunger.com and https://www.ucpress.edu/go/endhunger!)–I was strongly compelled to respond based on the mention of Garrett Hardin, who (like me) was an ecologist and, to my mind, has done a great deal of violence to our understandings of complex issues:
    ‘A telling precept behind Malthusian thinking is the idea that there are too many of “them” (Harvey 1974; Sen 1994). That is, when thinking about the effects of people overpopulating their food source, the “people” who are the object of analysis tend to be those in some other country, community, or social class than those conducting the analysis. Geographer David Harvey argues that this is no coincidence. In fact, he points out, Malthus explicitly argued that his ideas did not apply to the wealthier class, who by all Malthusian logic should also breed themselves out of wealth, house, and home. Thus we see that Malthus essentially proposes that there are two types of humans: the rich and the poor, also known as “us” and “them.” “We” can wisely govern our resources and population through policies that are collaborative and rely on “reasoned human action.” “They,” however, will need their reproduction to be controlled more coercively, or even through directly repressive means. It is clear that such an attitude benefits the rich and, to a large extent, the middle class in each society, as well as the residents of the industrialized societies of the Minority World. Garrett Hardin’s classic (1968) thought experiment of the “tragedy of the commons” draws on a logical structure similar to Malthus’s views. Indeed, in a lesser-known article “Lifeboat Ethics: The Case against Helping the Poor,” Hardin (1974) explicitly argues that we may not be able to “save” all of the world’s people given the limited resources of our biosphere (the “lifeboat” of the title). Given that we must choose whom to save and whom to let perish in the sea of poverty around us, he admonishes the reader not to give in to soft-hearted liberal ideals: they will merely lead to overloading the lifeboat and drowning us all. Similarly, we should not capitulate to characterizations of historical misfortunes and inequalities that might imply “we” do not deserve to be in the boat by ourselves in the first place, because such noble thoughts are nonetheless misguided and, again, lead to disaster for all involved. But a funny thing happened on the way to the lifeboat. Hardin explicitly organizes his thinking around “we.” “We” have to make these tough decisions. “We” need to get over our ethics and deny “our” resources to those who would simply keep reproducing, as “we cannot safely divide the wealth equitably among all peoples so long as people reproduce at different rates.” The problematic immigrants and peoples of the Majority World that he advocates excluding are assumed not to be “us,” even if “they” may comprise a significant part of his readership. We could hardly ask for a better demonstration of the relevance of cui bono, and a certain perverse Panglossianism, laid bare in what could be faithfully rephrased as, “It just so happens that my logic says ‘we’ get to live, and ‘they’ get to starve and die.” How fortunate (or unfortunate depending on the vantage point) that such “logical” reasoning benefits “us” and dooms “them,” but those are the breaks in this, the best of all possible worlds. We might better apply what I call we bono to this sort of motivated reasoning. That is to say, we might suppose that the more a chain of reasoning places burdens or costs on others, or maintains or improves a beneficial status quo for the reasoner, the more likely the reasoning is incomplete or incorrect…”‘

    tl;dr: Read
    de Sherbinin et al, Population and Environment (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2792934/)
    Amartya Sen, Population: Delusion and Reality (https://student.cc.uoc.gr/uploadFiles/1116-%CE%A6%CE%99%CE%9B.105%CE%92/Sen%20popullation%5B1%5D.pdf)
    Glenn Davis Stone, Overpopulation? Don’t bet on it: https://fieldquestions.com/2013/09/09/overpopulation-dont-bet-on-it/
    And Graham & Boyle (Graham, E., and P. Boyle. 2002. “Population Crises: From the Global to the Local.” In Geographies of Global Change: Remapping the World, 2nd ed.,
    edited by R. J. Johnston, P. J. Taylor, and M. J. Watts, 198–215. Malden,
    MA: Blackwell.)

    • Jahi,
      It will take me some time to look at all the sources of information you provided but I thank you for the recommendations. I don’t agree with all of Hardin’s views but I wouldn’t go so far as saying he “has done a great deal of violence to our understandings of complex issues..”

      I think he understood just how complex issues were and believed that our interventions to alleviate poverty in undeveloped countries through development projects often had unintended consequences in the long run.
      For example this excerpt from one of his articles An Ecolate View of the Human Predicament. http://www.garretthardinsociety.org/articles/art_ecolate_view_human_predicament.html

      “The basic insight of the ecolate citizen is that the world is a complex of systems so intricately interconnected that we can seldom be very confident that a proposed intervention in this system of systems will produce the consequences we want. Rachel Carson’s Silent Spring is a monument to this insight; so also are the many contributions in Farvar and Milton’s The Careless Technology.”
      I think many current ideas of geoengineering our way out of climate change is going to be another example of this.

      “The possibility of causing more harm than good seldom enters the mind of an international intervener…The goal of maximizing a single variable is woven into the fabric of engineering, and it has long seemed an innocent tool…Survival of any system depends on a subtle and incompletely understood balance of many variables. Maximizing one is almost sure to alter the balance in an unfavorable way. So complex is every natural system that the cascade of consequences started by an ill-advised maximization of a single variable may take years, or even generations, to work itself out.”

      As an environmental scientist and civil engineer I have seen this happen more often than not on many projects. When humans try to intervene we seldom anticipate all the consequences.

      I also agree with his thinking about poverty seen as shortages versus ‘longages’ of demand. “The problem of poverty is almost invariably seen as one of shortages-shortages of supply. But note: poverty can just as logically be seen as a problem of longages of demand. Given these two equally logical modes of expression, why do people invariably choose the first as a guide to action, scarcely even mentioning the second? This is a deep question. The usual choice is tragic because the well documented conclusion from ecology is that only the second approach-attempting to diminish the longage of demand-has any chance of succeeding in the long run. The ecological theory of matching supply to demand is grounded in the concept of “carrying capacity.”

      I think the Western lifestyle places an terribly high demand on the resources. What if we really were able to discern the difference between needs and wants? What if we could keep our wants small and supplies local? What if we did everything in our power to help the environment we live within could renew itself?

      I agree with Joe about the value of small farmers and I include urban small farmers in that group. I think we learn a lot about simple living and natures renewal when work the land with our hands and hand tools, growing some portion of our food. I learned more clearly how much energy we consumed in our home (and wasted) when we decided to install solar PV energy and live off of what we could afford to generate. Curbing our energy use, growing, cooking, and preserving food is a relatively small way of trying to understand what we consume.

  18. That is, no amount of chiding or analytical forcefulness is likely to manifest as the needed changes on the ground; the problems go beyond our attitudes and into the messy policy details that are hard to dictate and design at grand scales. (Though focusing more on redistributional issues, power, gender relations, and international economic inequalities seem clear to me to be *more important and likely to be effective*, if you will, than focusing on population per se, even with all the complexities.)

    This excerpt summarizes the tenor of the whole comment, which could be condensed even more into “The issue of ‘over-population’ is too complex and difficult to be solved, so let’s concentrate on making life better for everyone now”, sentiments with which I agree heartily.

    But even if the population bull cannot ever be run out of the china shop and we must concentrate all our efforts on protecting the china, we shouldn’t be surprised if, every once in a while, someone points out that ,”Hey, there’s a bull in our china shop”.

    • The “tenor” of my comment may be “The issue of ‘over-population’ is too complex and difficult to be solved, so let’s concentrate on making life better for everyone now”, but if so I have done myself a disservice as I disagree with that assessment! I was trying to make three points:

      (1) “Over-population” is *too simplistic a term to refer to the actually complicated problems we face*. We face neither shortage of supply nor longages of demand, but rather mismatches of what counts as “supply” and “demand”. Is it really meaningful to condense all people of all incomes across many countries and contexts, some overconsuming, some underconsuming, most with enough food available within their country, into unitary demand, unitary supply, or a unitary population? (I believe the answer is no.)

      (2) Because the answer to the above is “no” we shouldn’t give particular credence to the idea that there is a bull in the china shop. The problem is people who say, “Ok, yes, it may be true that we have five cats, three vigilant guard dogs, an assortment of birds, and a belligerent calf in our china shop, but it’s close ENOUGH to just say we have a bull in this china shop, really.” Well, no — how you deal with a divergent menagerie is different than how you deal with a solitary bull. I don’t think it’s hopeless in either case. But it is definitely hopeless if one insists on calling the menagerie a bull for simplicity’s sake–one has to have a handle on the actual situation.

      (3) This argument goes back at least as far as Malthus and Condorcet, but I continue to agree with Condorcet (and Amartya Sen): equitably improving quality of life can alleviate pressure on our resources, allowing space for “reasoned human action”.

      Again, I highly recommend Sen (https://student.cc.uoc.gr/uploadFiles/1116-%CE%A6%CE%99%CE%9B.105%CE%92/Sen%20popullation%5B1%5D.pdf) on this. It is not “too complicated.” It is simply *more complicated* than is usually appreciated, and not amenable to global-scale analysis or pronouncements.

      • Love the menagerie metaphor. And without further ado may I riff on Shakespeare (a bit crudely perhaps):
        The first thing we do, let’s kill all the cats!

        And thanks too for the Sen ref. Looks good so far.

      • “Is it really meaningful to condense all people of all incomes across many countries and contexts… into unitary demand, unitary supply, or a unitary population?”
        “It is… not amenable to global-scale analysis or pronouncements.”

        Bingo. The many contexts give distorted results when total (global) population is a multiplier.

        Chris’ equation,
        I = p∑iv (Where I = total impact, p = total population…),
        for example, doesn’t cut it.

      • It certainly doesn’t. But recall that I prefaced the equation by saying “if we’re going to insist on writing an environmental impact equation with population level as an independent variable in it” – which I’d respectfully suggest carries the strong implication that such an insistence is something I dispute. Essentially, I was making the same point as Jahi. The benefit of writing the equation as I did is essentially didactic in negating Daly’s I= p x i by drawing attention to the importance of v. But it’s not ‘my’ equation…I’m not suggesting it’s especially useful. The sigma term surely suggests the loss of information to which you’re referring.

        Meanwhile, hats off to Jahi for winning Small Farm Future’s metaphor of the month award…

        • “But it’s not ‘my’ equation…I’m not suggesting it’s especially useful.”

          Okay, but you earlier called it:
          “my suggested formula I = p∑iv ”
          and claimed that it summed group impacts (which I disputed).

          Thanks for the clarifications.

          • Apologies if the following seems hair-splitting, but I think the underlying issues are significant:

            The formula I = p∑iv unquestionably DOES sum group impacts (though as discussed earlier I = ∑piv does it better, where p in this instance refers to sub-populations). Presumably what you’re disputing is the utility of the summation, not the fact of it. That’s fair enough. Though total impact is surely an important measure (total number of whales killed, total amount of carbon dioxide emitted, total mass of plastic in the ocean). And it’s useful to know the size of the sub-populations taking different values of v in that equation (in the whale example, at the national level most values of v for these sub-populations would be zero, but that’s not so much the case with GHG emissions). In other words, to use Jahi’s metaphor, it’s useful to know the number of cats, dogs, birds and calves and their trends. However, I think we’re agreed that just knowing the size of p in my original formula isn’t especially useful in itself. Maybe if you write the formula as I/p = ∑iv it better focuses the attention on v, where it ought to be.

            Anyway, I acknowledge that my discussion of this could have been clearer, and I prefer the I = ∑piv equation, so thanks for helping me work through this.

          • “The formula I = p∑iv unquestionably DOES sum group impacts…”

            Chris, what I’m not getting with your ; ) suggested formula is just how DOES it unquestionably sum group impacts, since i is the per capita impact, and to cover the entire population the presumed bounds of the summation go from 1 to p individuals (with v defined as representing the individual differences, not group differences). Also, since you’re essentially summing the individual impacts across the whole population, why not just stop there, since this can give the total impact (after all, the formula is for I which is ‘total impact’)?.  Instead, what seems to be occurring is a re-jiggering of the individual impacts to come up with some kind of weighted per capita impact that can then be multiplied by total population p to result in total impact (in a circuitous way).

            Could you clarify this? (I freely admit that I might be missing something here, and I’m here to learn.)

          • To clarify, when I wrote “since you’re essentially summing the individual impacts across the whole population, why not just stop there, since this can give the total impact”, what I meant was to drop the p and simply the formula to:

            I = ∑iv

            since the summation already covers the entire population (from 1 to p individuals).

          • OK Steve, you win. Looking at this more carefully I/p is per capita impact, so ∑iv in my original formula is per capita impact, so as you say i clearly is not per capita impact. But we surely need some population terms in there – to get I we need to sum p sub-populations with i impacts, so I = ∑pi. Thanks for helping me clarify this. I think my words were right but my algebra was wrong – a fair summation of my educational career.

      • some overconsuming, some underconsuming, most with enough food available

        Let’s look at each of the three cases which you believe shouldn’t be ‘condensed’ into one.

        For those of us in the rich world, our over-consumption is dealing a death blow to the earth’s environment. It seems to me that things would definitely better for everyone if there were less consumption going on. While there may be many ways to reduce consumption, having fewer people over-consuming would certainly be better than having more people doing it.

        For those who are under-consuming, presumably because there are too few resources available per person, one option is to create circumstances in which more resources are available. But even without changing the supply of resources, if the number of people doing the under-consuming were few enough, none of them would need to under-consume. Again, fewer people is better.

        And while it is true that most people have “enough food”, whether the methods (synthetic fertilizer, fossil powered tractors and trucks) used to get that food are sustainable over the long term is very relevant. The more people without a sustainable food supply, the more people at risk. This danger also applies to the over- and under-consumers.

        Correlation isn’t causation, but if all the issues that contribute to a sustainability crisis increase in lock-step with population, including carbon emissions, water supply shortages, fossil fuel depletion, chemical and plastic pollution, arable land area reduction, then there just might be a causal relationship. After watching this correlation hold true for many decades we shouldn’t be surprised if some people point out that all these problems would all be easier to solve if there were fewer people on the planet.

        There may well be an optimum method of arranging sustenance for every size population cohort imaginable such that there are never any environmental or human problems, but we have a proven track record of failing to find it. That’s OK, because even if we can’t regulate the relationship between our population and the environment very well, nature will eventually do it for us.

        • Joe, I’d be interested to see Jahi’s response.I guess mine would be something along these lines – yes, it would be good if there were fewer high consumers, but as we know from rebound effects and large variation in per capita impact even at the high consumption end, reducing the population of high consumers won’t necessarily have much of the desired effect. And in the case of ‘under-consumers’, though there may be some local resource pressure issues, for the most part their under-consumption isn’t caused by their local numbers, but by the fact that value is systematically squeezed out of them by the rich world. So, for example, if the population of Haiti was 8 million rather than 11 million I’m not sure most Haitians would be much richer – the issue really is the way that poverty is systemically reproduced in poor countries like Haiti in general by the workings of the global economy, and in Haiti’s particular case also the way it’s been punished since 1804 for having a successful anti-colonial revolt (though that’s not to absolve its leaders from a degree of culpability). However, since fertility rates are plummeting in most countries, rich and poor, it seems sensible to stick where possible to policies that are supportive of this trend, and in the main these aren’t population control policies as such.

          • Yes, Haiti’s poverty is not necessarily due to its population density, since there are wealthier places with far greater population concentrations. But comparing Haiti with those other areas, or with rich countries that are ‘systematically squeezing’ them, and noting that Haiti could easily be lifted out of poverty if we only changed “the workings of the global economy” is to concentrate on one tree, rather than the forest.

            Looking at the forest reveals that the sum total of human economic activity is already too great for the health of the planet. Redistributing it doesn’t change the fact that the present level of resources devoted to human lives is not sustainable.

            If we divided the truly sustainable level of economic activity by the present population of the world we would get a GDP per capita that is less than that of Haiti right now. So few resources would be available per person that the death rate would rise and total population would fall.

            The only way that the earth is capable of supporting a situation where 96% of mammal biomass is humans and their livestock and where total plant biomass has been halved is due to the high energy throughput from fossil fuels. If we don’t stop using fossil fuels the climate will be badly damaged. If we do stop using them and don’t substitute another energy source of equal power we won’t be able to keep 7.6 billion people alive.

            Jahi’s claim that, “We face neither shortage of supply nor longages of demand, but rather mismatches of what counts as “supply” and “demand”, is simply too short sighted. We don’t have a shortage of supply right now because we are burning through a one-time stock of fossil sunlight that won’t last much longer and shouldn’t be used any more any way, not even in what appears to me to be a futile attempt to build a new, non-carbon energy system.

            I simply think that there is a lot of evidence from a lot of sources that the human population of the earth is in a great deal of overshoot and won’t be sustained. That’s the problem.

          • Dear Joe:
            You said: “…and noting that Haiti could easily be lifted out of poverty if we only changed “the workings of the global economy” is to concentrate on one tree, rather than the forest.

            And in its own way this assertion is logically defensible, but I think it misses a larger point. If by modifying the workings of the global economy we can help one tree then might we also help other trees in the forest? And to the larger point of putting out fires and/or playing whack-a-mole with tendentious environmental and societal difficulties when a very serious issue looms above our heads seemingly being ignored (population)… well, bailing water out of the lifeboat isn’t the long term solution, but refusing to bail water right now precludes our getting a chance at the long term solution.

            That 96% of mammalian biomass is humans and our livestock is an interesting statistic. I’m not convinced the number is quite that large, but will side with you that whatever the actual value, it must be greater today than it was a century ago. Are you aware of anyone estimating what a serviceable percentage of mammal biomass might look like?

            The one statistic I’ve got the most problem with is the halving of total plant biomass. Do you have a source for that one?

            There are plenty of challenging issues before us as we make our way in the world. Some require our immediate attention (and likely take up too much of our finite cognitive capabilities). Some challenges seem to get set aside as they don’t rise to the level of immediate doom. These latter stressors, such as affluent human environmental overshoot, deserve some slice of our current attention if for no other reason than their enormous eventual scale… but I think we need to keep some sense of hope alive.

          • I guess I’d say that ‘the health of the planet’ (who is ‘the planet’, and how to do we measure its health?) and ‘overshoot’ (overshoot relative to what?) are quite tricky concepts…which is not to say I think they necessarily lack any bite. You could be right that current population numbers reflect a one-time fossil fuel bonanza and will soon diminish, but it’s not clear to me exactly what aspects of fossil-fuelled civilization are associated with increased human population. If anything, a smallholder-powered agriculture can support more people per hectare. Maybe the key population-boosting technology donated by fossil energy is nitrate fertiliser. Though at this point I’m expecting a regen ag fan to pop up and tell me that the soil biota can do a much better job. In which case, we’ll be just fine – albeit most of us will have to work the land and stop using flush toilets or living in cities. Not sure I agree that it’s futile to build a new energy system, though it depends on the parameters. Meanwhile, it does seem to me wise to pursue policies, within reason, that support the current drop in fertility rates.

        • Joe wrote, “Redistributing it doesn’t change the fact that the present level of resources devoted to human lives is not sustainable. ”

          I agree, but that doesn’t diminish the need for redistribution. Even with a focus on the forest, individual trees do need some attention, because their health can affect the health of the forest.

          Taking a closer look at the Haiti example, and the issue of population: More than half of the Haitians (59%) are living below the national poverty line of US$2.41 per day, and about a quarter of all Haitians are living below the national extreme poverty line of US$1.23 per day (according to the World Bank). The fertility rate for Haiti is about 3 births per woman.

          In nearby Cuba, only 5% of the population is below the poverty line [Wikipedia], and the fertility rate for Cuba is only 1.6 births per woman, which is less than the fertility rates for the USA and the UK.

  19. Jahi – thanks for another informative comment. Much to ponder. And thanks for the links – I’ve found professional demographers seem to like keeping their cards close to their chest!

    Jan – well no, future trade probably won’t be for smartphones. But then they’re the sort of things that derive their utility from everyone else having one (the only reason I got one, about 2 years ago after doing perfectly well without one for 50 years previously). But a jade dagger from Italy in neolithic England is probably a more impressive trade item in its context. Of course it’s still a stone age tool…it was from the stone age!

    Joe – agreed…particularly with ‘time is too short to reform capitalism’…and not only too short, but I think it’s unreformable. However, I’m interested in addressing the ways in which it will change and the collective movements that form around changing it, as these will strongly shape the future.

  20. Jahi,
    Sen raises the question “…in view of the clear connection between development and lower fertility, why isn’t the dispute over how to deal with population growth fully resolved already? Why don’t we reinterpret the population problem simply as a problem of underdevelopment and seek a solution by encouraging economic and social development…?” This is an excellent point, but this leads to the question, what type of development is beneficial for people as well as the environment?

    I agree with her conclusion: “…there are reasons for worry about the long-term effects of population growth on the environment; and there are strong reasons for concern about the adverse effects of high birth rates on the quality of life, especially of women. With greater opportunities for education (especially female education), reduction of mortality rates (especially of children), improvement in economic security (especially in old age), and greater participation of women in employment and in political action, fast reductions in birth rates can be expected to result through the decisions and actions of those whose lives depend on them.”

    The problem I see is who controls the money for investment? There are two options: government investment on behalf of tax payers, and private investment on behalf of wealthy investors. U.S. government investment changes depending on current administration and we are apt to find inconsistent results. Private investment is generally possible only when corporations or wealthy private citizens choose to invest in foreign countries. Such investors prefer to high profits, their reason for investing in developing countries is not because of altruism but because of high rates of return on investment. So investment by someone other than the people living in the country itself is not likely to achieve the results that benefit the majority of its citizens.

    I liked what Glenn Davis Stone wrote https://fieldquestions.com/2013/09/09/overpopulation-dont-bet-on-it/:
    “In his wonderful book How Many People Can the Earth Support?, Joel Cohen put the 3 perspectives this way: we can have fewer diners at the table, we can bake a bigger pie for the diners we have, or we can teach better table manners.”
    “…How could there be too many diners at the table when we have so many leftovers? And how can the bakers get credit for solving our problem when they have served us pie as an entree and trashed the kitchen?” Wonderful comment!

    So how do we teach better table manners? I think “table manners” relates to our perception of wants and needs or “longages”? If we (long) for more and we have opportunity to acquire more even at the expense of others, isn’t this a moral issue? Having raised three sons I am well aware of teaching table manners. While I am not subscribing to religiosity when I evoke morals, I do believe that it is important that we are taught what is right and what is wrong.

    I don’t see the problem being the exact number of children we have but rather can we support the number of children we have. Support not only includes raising them, it also includes what happens when our children reach adulthood. What happens when they look for opportunities for livelihood within society, in order to establish their own household? If our society does not contain sufficient opportunities one might wonder why the parents choose to have more children.
    The other issue I think important to consider is if we live in places where climate change (drought, heat waves, storms) is making food and water security more difficult, think it important to consider the fact that migrating with children is very difficult.

    • I think Dr. Sen is a man. Not to be all gender sensitive, but he might care.

      On the issue of allotting child bearing to ability to support them – I think this is a wonderful concept on paper, but the separation in time between having children and being in a place to usher them into the world on their own is sufficiently large to make it a hard concept to put in place. Insurance helps of course, and societal safety nets play an important role, but it is still a complex issue. Perhaps as important as how many children is the importance of taking the responsibility to educate any and all in such a manner as they are ready to be ‘in the world’. Beyond a formal school education are all the behavioral expectations society might proffer. And being prepared for societies’ expectations to change as the landscape is changing is also a lesson to impart.

      I think your ‘table manners’ point goes directly to this and I will probably echo the notion at some point somewhere. So thanks for that. 🙂

      • Clem,
        I stand corrected. I shouldn’t have assumed that Amartya was a female name.
        I agree that the 20 years or more between parents choosing to have children and those children entering adult life is sufficiently large that our reasons for having children have become obscured. But I think good parents still feel responsibility for our offspring no matter what their age and this includes our grandchildren. Family is the first set of bonds that create society. A society made up of families that are healthy, connected, and supportive is a society that takes care of people in general because we want everyone to thrive.

        Back in the 1970’s when I first adopted the recycling philosophy (reduce-reuse-recycle) it came easy to me because my grandmother had lived this way. She was strongly affected by her experiences living through the Great Depression. She passed on her values to her children and grandchildren.

        I still believe this philosophy is important because it teaches us to value resources, although far too many Americans no longer think this way. If we are conscious of the resources we use it tends to make us thrifty and frugal when necessity calls. We think about home energy use, automobile fuel efficiency, the size of our homes, and the food we eat (or waste). Just because we can live wasteful, over-consumptive lives doesn’t mean we should. Table manners!

    • Jody wrote, “If our society does not contain sufficient opportunities one might wonder why the parents choose to have more children.”

      In some ways, this is like wondering why so many people in our society choose to incur massive college debts, when our society does not contain sufficient opportunities for so many college graduates. There’s a certain logic being followed, though, with examples of success stories, along with other cultural influences that aren’t quite keeping up with the realities of the current economy. A college diploma is becoming less like a meal ticket and more like a lottery ticket. Poverty and desperation might make people more likely to make decisions that they will later regret (like decisions to play the lottery).

      I recall reading that one reason for having lots of children per family, in the poorest countries typically having high inequality, is that each child in the family is like a lottery ticket, increasing the odds that someone in the family will get one of the relatively well-paying jobs in the city, and therefore be able to lift the entire family out of such grinding poverty. This is in addition to the other reasons that I think were mentioned earlier (child mortality rates, helpers for the fields, old age ‘social security’).

      This NYT article about Nigeria mentions this “playing the lottery”, along with the desperation and later regrets about having so many children, and how the cultural influences aren’t keeping up with the realities of the economy.


      I’ve never had to live in such grinding poverty, in such a society. ‘There, but for the grace of God, go I.’

  21. Chris,
    I’ve begun reading“Smallholders, Householders” Robert McC. Netting (1993) I thought this a very interesting point.
    “Small holders are rural cultivators practicing intensive, permanent, diversified agriculture on relatively small farms in areas of dense population. The family household is the major corporate social unit for mobilizing agricultural, labor, managing productive resources, and organizing consumption.” p.2

    “Where money, legal titles, notaries, and courts exist, as in medieval Switzerland, land is bought and sold, and its price seems remarkably high. But even where market relationships are exonomically insignificant and no state legal system intrudes, as among the pre-colonial Kofyar and the Philippine highland Ifugao, households have clearly defined, very valuable rights in real property, and land is heritable. With the assertion of continuing use, occupation, temporary exchange by loans or lease, and public “litigation” over disputed rights, an institution very close to private property comes to exist, even if permanent alienation by sale seldom occurs. Individualized, socially recognized rights to scarce, highly productive resources and the improvement that increase and maintain their yields are inherited along lines of close kinship or transferred in exchange for other valuable goods. At the same time and place, land with low or temporary production with little potential for intensification, as in marginal, long-fallow bush fields or rough grazing areas, may remain in communal tenure with occasional redistribution or shared, controlled access (Netting 1969s, 1982a). The documentary evidence that the resident families of the Swiss village had exercised private property rights in irrigated meadows, grainfields, gardens, and vineyards since the thirteenth century while maintaining legally instituted common property in the community alp and forest convinced me that there was no evolutionary watershed separating as earlier stage of communal rights from a later period of private property emerging with the market and the state (Netting 1976). Smallholder intensive cultivators hold land, and, all other things being equal, it is the ecological factor of land use that most strongly determines land tenure.” p.10

    I agree with his definition of small holder. I also agree with his thinking that small holders have historically “held” their land through the process of working the land. If one cares for the land they occupy and makes it more productive, is isn’t really an issue of ownership is it? As long as society’s laws don’t prevent one from staying on the land you are working.

    • Yes – by way of background, Netting’s ethnography of private and common land in Alpine Switzerland was quite influential on Elinor Ostrom’s analysis of common pool resources – which, as I’ve argued in previous blog posts, is less supportive of commons as a fundamental way of organising production than a lot of people suppose…Netting’s book only confirms my thinking on that point.

      As to property ownership, the key point about it is that it’s a socially-sanctioned relationship between people, not fundamentally a relationship between a person and the thing owned. If my family ‘owns’ this farm, and your family doesn’t, what that means is that our society has agreed that my family has the right to derive income and produce from the farm while yours doesn’t – what’s significant is my family’s rights with respect to your family’s rights, the relationship between us. In practice, property rights are rarely total – there will likely be numerous usage limitations. Nevertheless, I’d say that, yes, Netting’s book establishes very clearly to my mind that in intensive, high population farming situations, private family-based farm ownership is a very common mode of social organisation cross-culturally. I think this is tremendously important, and I hope to write some more about it soon.

      • The same kind of quasi-private land tenure was prevalent throughout the Pacific also. While paramount chiefs could overrule land rights if they desired, they rarely did so (unless of course the land in question was recently taken from another chief’s domain). Often there were very severe penalties for theft or other encroachments on land that was not ‘yours’.

        In Hawaii, land was sectioned around the perimeter of the island, with dividing lines going from the sea coast to the nearest mountain top.

        In the Marshall Islands the dividing line went from lagoon to the ocean side, slicing small atoll islands into even smaller parcels.

        In both island cultures, even though family groups managed these smallholdings for their own benefit, they were also ‘taxed’ to provide for those who weren’t actively engaged in food production.

        There were also areas held in common, such as ocean fisheries, the management of which was organized by the hereditary rulers and their minions.

        So yes, I think it is fair to say that the concept of exclusive use of land that is very similar to modern private property rights has a long and widespread history and that it is also true that such ‘ownership’ was always socially regulated to be much more conditional than the ownership of things like a pair of shoes or a knife.

      • I’ve come to believe that the problem with land degradation too often follows absentee landlord-ism. The value of smallholders and householders is that they perform their work with both skill and affection. I tend to think of this as land stewardship rather than ownership. Owners who live far away, who only see property as something to buy and sell, seldom feel a responsibility to care for the land they own.
        I also extend this “stewardship” thinking to the efforts of raising children. Perhaps that is why I believe that its my responsibility to choose the size of my family based on the my ability to care for and about them.

  22. It’s hugely frustrating to read such a naive article which purports to answer concerns about population growth from a position of ignorance, just trotting out a few old wives’ tales. Those of us seriously concerned about population growth know intimately how fertility fell in lots of countries. And we know which countries still aren’t getting there. And we know that those countries are enough to destabilise the whole global project. And, for all that speculation about development and empowering women driving the ‘demographic transition’, we know that it was deliberate, well-publicised voluntary family planning programs that brought fertility down rapidly, in those countries that implemented them (including China, in the decade BEFORE the one-child policy, so it wasn’t ‘voting with their feet’ but being very purposefully directed toward good reproductive choices). But you fail to even acknowledge that such programs existed. Hence you fail to realise that, since the mid-1990s the world has given up on supporting such programs. Hence you fail to know that births have been increasing annually, even faster than deaths (which must increase as more people reach old age) so that global population growth has increased since 2000. And your maths might not be up to registering that births can increase even as fertility is stalled or falling slightly, because the numbers of mothers is increasing. It might be turning around right now – the data is not in, but a few African countries are starting to see the light and promote family planning actively. But that doesn’t mean the problem is solved – we need to get every one of the remaining high-fertility countries on board very quickly if any of the sub-2oC climate models are to have a chance – see https://www.researchgate.net/publication/320632925_Synergy_between_Population_Policy_Climate_Adaptation_and_Mitigation
    So let’s get straight about what the issue is here. Population growth is NOT fixing itself, certainly not fast enough to head off major environmental calamity. (If you think famines will fix the problem, then you don’t understand that that is exactly the problem.) We need the sort of attention given to population growth in the 1970s to be reinstated, so that family planning programs get the support that they deserve. And articles like this are just adding to the stack of obstinate, self-indulgent barriers to this outcome, without which we’re all in a very bad place.

    • I suppose I should be flattered that an obscure blogger like me should excite such attention from an apparent academic expert in the field, though the way you string together a bunch of logical non-sequiturs in sentences beginning with ‘Hence’, your apparent inability to distinguish between a quantity and a rate, your preference for assuming what I think rather than reading what I wrote and your haughtily dismissive tone (let’s hope the family planning professionals you extol don’t go about their business the way you do) are frankly quite irritating. My post was basically directed at grossly generalized barstool-type arguments (and their scholarly equivalents) that ‘population’ is ‘the’ problem – nowhere do I suggest that family planning services are a bad idea. I’m not an expert in this field, but it strikes me that for reasons best known to yourself you’re asserting links between family planning and population and between population and climate change much more unequivocally than is warranted by the balance of opinion in existing scholarship…and a lot depends on the parameters of the analysis in any case. Banerjee & Duflo state for example that “the data seem to squarely hand victory to the demand wallahs: Contraceptive access may make people happy by giving them a much more convenient way to control their fertility than the available alternative. But it appears to do, in itself, little to reduce fertility” (Poor Economics, p.112). While your contention that it’s the experts and health professionals who’ve held the line against the lusty masses is interesting and certainly worthy of more study on my part, I find some of your claims puzzling – global population growth has not increased since 2000 according to the datasets I’ve seen, trends in births and fertility rates are very obviously different things, and while it may well be sensible to invest in family planning services as a climate change mitigation strategy in particular settings your stridently populationist rhetoric seems curiously silent on the issues of fossil fuel combustion and social inequality. I’ll have a more careful read of your linked article, but I’m struck by your claim that “achieving replacement level fertility in sub-Saharan Africa by
      2050 would spare an area of forest and savannah larger than Germany from conver-
      sion to cropland, and in doing so save 16 Gt of carbon dioxide emissions (Searchinger
      etal., 2013” – I can’t find any mention of this 16 Gt figure in the Searchinger article you cite, but presumably this is a total figure over an unstated time period – maybe the 30 years between now and 2050? – in which case the monumental achievement of reducing fertility across all of sub-Saharan Africa to replacement levels within 30 years would amount to only a 5% reduction in global emissions at present levels. I have no doubt that improving family planning services in sub-Saharan Africa is a good idea, but I’m also left with the impression that you’re treading too close to the ‘let’s blame climate change on all those poor people over there’ narrative for you to hurl insults about my self-indulgence from your own glasshouse…

      Addendum: …but to help me improve my analysis, I’d be interested to know what are the specific ‘old wives’ tales’ (a rather unfortunate metaphor, in the circumstances) you think I’m recycling and where I can find the balance of alternative opinion. I’d also be interested to know what you consider ‘the global project’ to be – to my way of thinking there’s no such thing…though that’s not to say there are necessarily no common human interests.

      • Dear Chris,
        Apologies if the tone of my comment was harsh – it was a late night and the preachy tone of your blog got under my skin.
        Let me first say that I work on this issue because population growth is the main driver of impoverishment and local environmental damage in high-fertility countries, and their prognosis is looking grim if fertility is not rapidly brought down. The research I have done shows that the countries that reduced fertility benefited enormously from doing that, and indeed it would seem to be an absolute prerequisite for economic development unless (and only as long as) they have major oil income. Population growth is also a major driver of inequality, as the oversupply of labour inevitably leads to exploitative terms of employment. So I deeply resent the entirely undeserved “you’re treading too close to the ‘let’s blame climate change on all those poor people over there’ narrative” when you haven’t even read my paper. Concern about population growth is concern for the poor. Those who try to diminish the issue are doing the poor a very great disservice.
        Re “the human project”, I would have thought we all agree that we’re trying to create flourishing, sustainable, peaceful societies in which everyone can enjoy sufficiency, security, dignity and some level of autonomy.
        I did not accuse you of saying family planning services were a bad idea. I accused you of ignoring the fact that family planning programs intended to reduce fertility ever happened, and attributing their successes to passive indirect effects of education, development and “people voting with their feet”. You speak of the low effects of access to contraception on fertility, and I agree – it was the promotion of small family norms (a short-hand for a range of messaging through a range of interventions – don’t take me to task on narrow interpretations) that was vital to the successes of the ‘70s and ‘80s, and which has been wiped from the understanding of what family planning is today, resulting in very slow progress on fertility decline in remaining high-fertility countries. So, where you refer to “family planning services”, you appear to mean the supply of contraception, which was only a part of the integrated programs designed to bring fertility down while also delivering reproductive health services.
        Re Searchinger’s paper, try searching it for “16” – I just did and found the quote easily enough. It was not central to my argument, so I don’t know why you try to attack me over it.
        Re “global population growth has not increased since 2000 according to the datasets I’ve seen”, look at the UN’s tables. Here’s an excerpt:
        Year Increment (millions)
        1999 78.02
        2000 78.14
        2001 78.41
        2002 78.74
        2003 79.26
        2004 79.96
        2005 80.79
        2006 81.69
        2007 82.57
        2008 83.35
        2009 83.97
        2010 84.43
        2011 84.84
        2012 85.17
        2013 85.25

        Old wives tales:
        “unnoticed by many – global fertility is crashing at a historically unprecedented rate”
        Looking at your own chart, you should see immediately that the rate of decline for the world over the past two decades is much lower than that over the preceding three. And this tapering off has happened well above the “replacement rate” of about 2.1 children per woman, which means we still have far higher fertility than would support population stabilisation, let alone a decline. So “is crashing” seems misplaced here – it stopped “crashing” in the 1990s. The “unnoticed by many” is a deliberate put-down to people expressing concern about population growth, claiming they are just ignorant and disinterested in checking their facts.

        “for those who say that not enough is being done to reduce population, I wonder what realistic policy measures they believe could have been implemented over the last fifty years that could have improved on this 50% fertility decline.”
        My answer is that this decline is an averaging of the countries that proactively worked on reducing fertility through voluntary family planning programs and those that didn’t, and what we need is for those that didn’t to start doing it asap. Why do you decide that 50% decline in 50 years is so superlatively good? Why are you unconcerned that the decline tapered off before reaching replacement rate?

        “not many countries apart from China have implemented explicit population control policies”
        Try South Korea, Taiwan, Thailand, Vietnam, Sri Lanka, India, Indonesia, Bangladesh, Mauritius, Tunisia, Morocco, Egypt, Iran, Botswana, Zimbabwe, Kenya, Ghana, Maldives, Puerto Rico, Colombia and others (not to mention those where it was driven by NGOs more than govt policy).

        “Certainly, it would have been hard to implement official population control policies globally as effective as this gigantic act of self-implementation”
        The ‘gigantic act of self-implementation’ only happened where there were voluntary family planning programs (population control policies) to motivate them.

        “many countries are going to face significant social problems in the coming century as a result of this demographic collapse”
        The likely pace of population decline is less than 1% p.a. in most countries (those that have had higher declines are due to emigration, in response to economic malaise, not causing it). Why call this ‘collapse’? Is this not “stridently populationist rhetoric”, to borrow a phrase from you? What evidence of ‘significant social problems’? There is no reason to think that this is more problematic than 1% population growth – indeed it is less so, since we don’t need to build stuff for no other reason than accommodating more people. Aging is an inevitable product of longevity, it does not mean more infirmity, and changing our population growth rate will have very little effect on it. Nor does aging represent any real threat to the economy, as the proportion of people employed is determined by the demand for their labour, not by the supply of working age people. The countries with most people over 65 have no fewer working hours per head of population than those with younger profiles. It’s a big beat-up by the “growth is God” crowd.

        “The billions of people who live on just a few dollars a day certainly do have an environmental impact, but it’s really not them who are driving the drastically negative impacts in the contemporary world.”
        The objection here is that it is intended to dismiss and belittle population concern. I have no intention of diminishing the impacts of high resource-consumption lifestyles, but actually those haven’t got more resource-intensive nor emissions-intensive in the past several decades (which is not to deny that reducing their impact is vital and urgent). The big increase has been the number of people starting to share those lifestyles, in transition countries. But, apart from climate change, most of the “drastically negative impacts” (on deforestation, soil erosion, biodiversity loss, fertiliser run-off, plastics in the ocean, overfishing, destruction of wetlands, draining of aquifers etc) is not happening in or in the name of the most industrialised countries. Sure, some of it is because of adoption of technologies introduced by the West, but without those technologies (especially fertilisers and irrigation) there would have been a lot more land conversion and a lot of famine in recent times (unless the health and sanitation technologies also failed to be transferred, in which case we’d just have a lot of infant and maternal deaths keeping populations in check – not such a victory for the poor). If we think about a person’s environmental impact as the legacy of their lifetime actions, then their reproductive choices and all their descendants count as their impact also. There are few least-developed countries where per capita footprint for land-use is so low that the legacy of their people in 1950 isn’t greater than the legacy of Europeans at that time. Attribution is not blame. But if we deny attribution, we are chasing false solutions.

        “historically very high, but soon to be declining, numbers”
        The UN doesn’t project a decline this century. The UN has been consistently underestimating growth since 2000, as it is consistently overestimating the rate of fertility decline in the high-fertility countries. The track we’re actually on might well exceed 13 billion by 2100, and still growing strongly, unless checked by calamitous mortality events. It’s calamitous mortality events that I’m worried about, not crowds. I think it is irresponsible to talk about near-term decline as if it’s already in the bag, when there is so much more that can be done to minimise growth and reduce the risk of massive die-offs.

        “The reasons for the astonishing fertility decline don’t seem completely clear, but are largely to do with the demographic transition (declining birth rates following declining death rates) and ‘modernization’, generally speaking.”
        The ‘demographic transition theory’ of ‘modernisation’ driving fertility decline has relatively weak support in evidence. Here again, you ignore the existence of the voluntary family planning programs, which are very clearly linked with most cases of rapid fertility decline.

        “the evidence suggests that in situations where population pressure on land is a limiting factor (which could well be the case for a lower energy, small farm future in a country like Britain), people attempt to keep their fertility levels low”
        In the current world, that could only be a case of data-picking. There is also evidence that, in many largely rural communities, high fertility persists despite the desperate poverty that it generates. Your statement is not entirely untrue, as it seems that when outmigration or import of food means that land is not limiting, then there is less incentive to limit births. This just removes the impacts from view, it doesn’t overcome them. But your policy recommendation, if achievable, of ensuring employment opportunities for youth, would serve to defuse the motivation for low fertility that you mention here.

        “ultimately our societies will be replaced by ones that are better able to farm and function at sustainable levels of energy use by attending more to v and not so much to p in equation (3) above.”
        The only way such a sustainable society could exist is by having already attended to p. With too many people, low-impact mixed farming is no longer an option. Nitrogen fertilizer becomes essential, and somehow you’ve got to close the nutrient cycle that at the moment runs one-way from soil to sea. If “ultimately” means after the apocalypse, among the scattered remnants of humanity, you could be right. But it skips the entire point, that it is the apocalypse we’re concerned about.

  23. Jane, thanks for your response. I find it largely unconvincing. I’ll try to set out the key points as I see them.

    1. Focus of analysis. To some degree I think we’re talking past one another. My original post was aimed at the view – quite widely expressed in general public discussions of environmental problems – that ‘over-population’ is ‘the’ problem, and that it’s getting worse (somebody said to me recently that human population is growing ‘exponentially’). You seem to be coming mostly from the position that policies to reduce fertility in impoverished, high fertility countries are a good idea. These are not mutually contradictory positions, so I find your animus against my post a little baffling in the main.

    2. Blaming the poor. I’m sorry if you resent the affinity I impute between your position and a victim-blaming one, but really if you take the positions you do so emphatically I think you should expect it. Given that sub-Saharan Africa is the part of the world where both high-fertility and poverty are most concentrated, given the long history of colonial and neo-colonial destruction visited on it which is ongoing in terms of large financial outflows from sub-Saharan Africa to the rest of the world, given the racist history of blaming Africa for its ills and given the voluntaristic discourse around fertility, surely you must see the potentially troubling political implications of your argument that “population growth is the main driver of impoverishment in high-fertility countries”? One of the few comments I’ve ever moderated off this site was a racist disquisition on African fertility that included such comments as “Africans presently reproduce at a rate of over 5 offspring per female due to their low IQ, high time preference, and evolutionary ingrained reproductive strategy (serial marriages)”. I’m not for a moment suggesting that you share any such sentiments or that you aren’t motivated by entirely laudable anti-poverty aims, but if you’re unaware of how your arguments might play in different circles I suggest you wise up fast. The associations between fertility and poverty strike me as considerably more complex than your bald assertion above.

    3. Re. Searchinger’s paper. Sorry, a search on ‘16’ comes up blank at my end, but the reason I picked up on this, as per points 1 and 2 above, is that 16 Gt of carbon dioxide emissions is a hell of a lot of carbon dioxide – nearly half of the entire world’s annual emissions. To me it sounds a suspiciously high figure to impute to land use change to an area of Africa about the size of Germany. Perhaps it’s accurate, but it surely must apply over many years? A casual reader might think “my God, if only those Africans could control their fertility then we could cut about half our global emissions right there.” But they’d be wrong, surely?

    4. Population growth. OK, so you’re referring to growth in absolute numbers of people rather than the growth rate, which has declined year on year since 2000. Fine – but then why say that the world has given up on family planning programs and imply that this is the reason that population has grown since the year 2000? If we’re looking at absolute growth, then what significance does the year 2000 have? When was the last year that global population didn’t grow in absolute terms? A hell of a lot longer ago than the year 2000 for sure. This more than anything else you’ve written makes me think that you’re spinning a line.

    5. Global fertility crash. Yes, the rate of fertility decline is slowing, but it’s still declined every single year since 1965 (and didn’t slow much until the late 1990s). Why the slowdown? I don’t know, but I’m suspicious of your vehemently-asserted monocausal explanation. I have no expertise in this area, but I’m willing to stick my neck out on the basis of my general background in social science to suggest that it’s very unlikely that a gross social fact such as a slowing global fertility decline has a single cause, that it’s very difficult to test the causes empirically so well that one can confidently delineate them, and that there are therefore likely to be greater differences of opinion and interpretation in the field than you entertain in your singular assertions. Other possible explanations that spring to mind are statistical artefact (it’s intrinsically easier to reduce fertility from 5 to 4.5 than it is from 2.5 to 2) and growing global inequality/stalled ‘development’ resulting essentially from the development of the neoliberal global political economy. I don’t doubt that reduced FP programs are also significant, but I do doubt that they’re as significant as you assert.

    My “unnoticed by many” comment isn’t intended as a putdown to people concerned about population, it’s an assertion on the basis of my experience that a lot of people don’t know that fertility has been declining over the last 50 years. Why do I think that this 50% decline in 50 years is so good? Well, maybe I’m wrong – what would count as ‘good’ in your book? Are there examples of stronger large-scale declines in the absence of Malthusian checks to draw on that relativize the progress over the last 50 years?

    6. Population control policies. You seem to have a very flexible and general definition of ‘population control’. If by ‘population control policy’ you mean the existence of voluntary family planning programs, then yes I accept that many countries have population control policies. To me it seems a strange conflation, but maybe it’s standard in the field. You concede that there’s a poor link between contraceptive availability and fertility, but go on to assert that it was the promotion of small family norms and other ‘messaging’ that was significant. My feeling is that you impute too much agency to professional, top-down ‘messaging’ and not enough to ordinary people choosing smaller families themselves for reasons that made sense in their own lived contexts, rather than being led by external expert influencing. I’d like to see some evidence (ideally including some debate and a range of opinions) for your view. Operating as I do outside academia I have limited capacity to find appropriate literature, and my searching on this particular point hasn’t borne much fruit. I found a 1997 paper by Bongaarts stating that “About 43% of fertility decline in developing countries was due to FP programs during 1960-65 to 1985-90” (I love the spurious precision of that ‘about’). Another way of saying that is that most of the fertility decline in developing countries was not due to FP programs. General, popular books touching on demography I’ve read by the likes of Danny Dorling and Banerjee and Duflo seem much less confident than you are about how to explain demographic trends and what the role of government policy and professional interventions has been. So I’m not yet convinced by your bald assertions about top-down FP programs.

    7. Legacy of lifetime actions. You write “If we think about a person’s environmental impact as the legacy of their lifetime actions, then their reproductive choices and all their descendants count as their impact also. There are few least-developed countries where per capita footprint for land-use is so low that the legacy of their people in 1950 isn’t greater than the legacy of Europeans at that time. Attribution is not blame. But if we deny attribution, we are chasing false solutions.” I find this logic tortuous and conceptually problematic, and in relation to my points 1 and 2 above in fact very likely to lead to false solutions to global environmental and socioeconomic problems, particularly when combined with your assertion that most negative impacts are not happening in the name of the most industrialized countries. This strikes me as a naïve interpretation of how the global political economy works. You say that the impacts of high resource-consumption lifestyles haven’t got more resource-intensive nor emissions-intensive in the past several decades – but here’s a case where looking at the absolute impact of these lifestyles across the full life-cycle of the resources they use rather than looking at the relative change in their intensity over time would be a more instructive way of apportioning responsibility.

    8. There are various other points where I disagree with you and one or two points where in the light of what you’ve said with hindsight I’d change some of my phrasing, but I think I’ll pretty much leave it there – in general, you haven’t convinced me that much of what I’ve said is fundamentally wrong. I guess it’s for others to judge if they wish how ‘preachy’ our respective comments are, and whether what I’ve written is ‘old wives’ tales’ or rather a set of contestable interpretations of the evidence, as most everything in social science is, including your intervention. But thanks anyway for engaging – I’ve certainly learned a few things from you, which I suppose ultimately is all a blogger can ask of a commenter.

    • Dear Chris,
      You seem to be not reading what I am writing. I am responding to you with evidence, and you are responding to me with baseless scepticism.
      1. You may say that your blog was challenging the position that “overpopulation is ‘the’ problem”, but this is a straw man. I don’t know anybody who thinks it is the only problem. You may be misinterpreting the frustrated utterances of people who are trying to point out that it is the issue which has been omitted from any particular thesis that they are responding to, and which renders that thesis flawed – but that is a different thing to saying it is ‘the’ problem. In any case, the arguments you made were not addressing that particular position. They were addressing a wider position, that we should be doing more than we are to minimise further population growth. You argued that we could not effectively do more, and that we didn’t need to. I am arguing that these are demonstrably false positions.
      Nevertheless, given that the planet is overpopulated (given the behaviours, technologies and institutions that we have, not some hypothetical world inhabited by angels) then yes, it is getting worse, as long as it grows. It would grow through demographic momentum beyond the point where we’ve done what can be done to minimise growth, and in that situation, your blog would have been appropriate. But that is not the current situation.
      2. “Emphatic position” – well excuse me for defending the interests of the poor, against those who would keep them poor by neglecting their population growth. Given the mathematical simplicity of population growth reducing natural resources per capita, I would have thought ‘bald assertion’ better fitted the position that denies that population growth generates poverty. Yet you can’t resist gratuitously quoting a racist comment, as if it has anything to do with what I have said. See https://www.populationinstitute.org/resources/reports/dvi/ on how population growth is a “challenge multiplier” and https://www.gatesfoundation.org/goalkeepers/report for a recent discussion of the link between demographics and poverty.
      3. Re the quantity of emissions avoided by averting land conversion to agriculture, of course all land conversion is a one-off carbon release, not an annual emissions tally. So 16 Gt is not that much in the scheme of all future emissions, but that was only the avoided births up to 2050, and it would make an even bigger difference in the second half of the century. Avoiding emissions is not the primary motivation for reducing fertility, as my paper clearly argues, but it is a co-benefit not to be sneezed at.
      4. Of course I’m talking about absolute numbers. They are what matters most. You ask “If we’re looking at absolute growth, then what significance does the year 2000 have? When was the last year that global population didn’t grow in absolute terms?” But my statement was “global population growth has increased since 2000”. That is, the annual increment, which had peaked in 1988 and was declining through the 1990s, started rising again from the year 2000.
      Relative growth rate is barely relevant. But actually the UN’s 2017 data suggests that the growth rate pretty much stalled at 1.23% p.a. between 2005 and 2008 – and the UN’s subsequent data is open to over-optimistic modelling given the length of time between censuses in many countries. The Population Reference Bureau’s annual world population data sheets recorded pretty much constant growth rate at 1.21% p.a. from 2010-2016 when they stopped publishing their annual population clock. So, given data uncertainty, it’s not at all clear that global population is NOT growing exponentially, or at least was for a period quite recently. I’m not saying it was (as I said, it’s barely relevant), but it’s certainly a more defensible statement than yours, that “fertility is crashing at a historically unprecedented rate”.
      5. As for what constitutes “good” fertility decline, countries with active voluntary family planning programs generally achieved 1.5 units per decade or better, over the first two decades, tapering off as they got below replacement rate, or as they reduced their efforts to promote family planning. There are a bunch of them plotted in a chart in that paper I linked for you. As I said, the global course is an average of those that acted, and those that didn’t.
      6. “Population control policies” is not a term that I generally use. But it was in response to your statement, which very clearly implied that China was the only country to explicitly take action to reduce fertility, and everywhere else was therefore entirely due to people ‘voting with their feet’ in a ‘gigantic act of self-implementation’. Of course fertility decline happened because of “ordinary people choosing smaller families themselves for reasons that made sense in their own lived contexts” – that is what VOLUNTARY family planning means. But it didn’t happen very much in the absence of messaging to break down the cultural conditioning that motivated large families, and to make the benefits of smaller families more widely known. This was done as part of ‘population policies’ (as the UN refers to them) explicitly intended to reduce population growth. So yes, they were population control policies. If you want to define ‘population control policies’ as something more draconian, feel free, but that was not the context in your blog.
      My attribution of effect to family planning programs is derived from looking at country level data and documentation on the programs they had. It is not gleaned from other people’s opinions. One piece of corroborating evidence is that under the Millennium Development Goals (2000 – 2015) all the supposed indirect drivers of fertility decline were improved quite strongly, yet fertility decline stalled in many mid-transition countries, and no new rapid transitions started. I am not denying that those factors have some influence. But the withdrawal of political support for efforts aimed at reducing fertility, which happened after the 1994 Cairo UN International Conference on Population and Development, was clearly associated with slow-downs in fertility decline, for which those other factors did not compensate.
      8. Re environmental legacy of individuals including the descendants that they choose to bring into the world, there have been several studies arguing the case, so it’s not only my logic. See https://www.theguardian.com/environment/2017/jul/12/want-to-fight-climate-change-have-fewer-children (since the scientific papers are probably not accessible to you). The same principle applies to people in developing countries as developed, and for other environmental impacts as for ghg emissions. I was specifically talking about land use, not ghg emissions. To put it differently, I was countering the idea that the world’s environmental and development problems would disappear if developed countries were magically removed from the planet. They wouldn’t – for many countries, they’d be worse off.
      Anyway Chris, I know where you’re coming from and I sense you’re well-meaning. But if you think you’re defending the poor against racists, you need to make sure you’re not having the opposite effect.

    • Chris wrote: “I can’t find any mention of this 16 Gt figure in the Searchinger article you cite, but presumably this is a total figure over an unstated time period – maybe the 30 years between now and 2050? – in which case the monumental achievement of reducing fertility across all of sub-Saharan Africa to replacement levels within 30 years would amount to only a 5% reduction in global emissions at present levels.”

      Chris is correct, that 16 Gt figure covers a number of years, but it’s more like 43 or 44 years, instead of 30 years.

      Searchinger, T. et al. 2013. “Achieving Replacement Level Fertility.” Working Paper, Installment 3 of Creating a Sustainable Food Future. Washington, DC: World Resources Institute.

      quoted from Page 8:

      “…Based on the FAO’s projected yield gains in the region, Sub-Saharan Africa will need to add more than 125 million hectares of cropland over 2006 levels to meet crop needs in 2050.[22] That area is comparable in size to
      Germany, France, and the United Kingdom combined. This growth is independent of any growth in cropland area for exports sought by many recent foreign investments in agricultural land in the region. Achieving replacement level fertility by 2050 would cut that needed cropland expansion by roughly one third, potentially sparing an area of forest and savannah larger than Germany. According to one reasonable estimate of typical losses of 100 metric tons per hectare of pure carbon when land in Africa is converted, this land sparing would save 16 gigatons [23] of carbon dioxide emissions.[24] A wide range of estimates exist for the alternative costs of reducing carbon dioxide emissions, but at prices of US$25 to US$60 per metric ton, these savings in carbon would avoid US$400 billion to US$1 trillion in costs of reducing carbon emissions by other means.”

      quoted from Endnotes:

      23. A gigaton is one billion metric tons.
      24. Gibbs et al. (2008) estimate above-ground carbon for seasonal and humid forests and savannahs in Africa to be 51 to 204 metric tons per hectare (depending on whether the lands are shrub or forest and if they are disturbed or undisturbed,) with potential soil conversion losses of 10 to 19 metric tons per hectare, assuming that conversion loses 25 percent of soil carbon (see Supporting Information Table S1.) The mix of land-use types converted is somewhat speculative, but even assuming a preference toward conversion of drier or degraded lands, one reasonable estimate would be a carbon loss of 100 metric tons per hectare, equal to 367 metric tons of carbon dioxide per hectare.

  24. Jane

    Well, your latest comment is quite the mix of interesting explication and misplaced finger-wagging. I’m not sure how much road is left in this debate since we’re coming at it from such different perspectives but I’ll respond to a few points and set out where I think I may need to shift my position and where I think you really ought to be thinking harder about where to shift yours. I’ll probably excerpt this whole exchange between us in my next post as I think others who read this blog might find it interesting.

    1. Political context. Rich white folks trying to best other rich white folks about their superior concern for the global poor is a game I’d rather not be playing, but it surprises me how unconcerned you are about the implications of your argument that population growth is the main driver of impoverishment in high-fertility countries. You contrast your ‘evidence’ with my ‘baseless scepticism’ but a lot depends on what evidence one chooses to emphasize and what happens to the evidence one marshals when it goes out into the wider world. A piece of evidence that strikes me as significant is the GFI’s analysis that since 1980 developing countries have lost US$16 trillion through leakages in the balance of payments, trade misinvoicing and recorded financial transfers. They say that sub-Saharan Africa’s assets held in tax havens grew at an annualized rate in excess of 20% from 2005-11: https://www.gfintegrity.org/press-release/new-report-on-unrecorded-capital-flight-finds-developing-countries-are-net-creditors-to-the-rest-of-the-world/ . So there’s just one small bit of evidence about the long-range historical and geopolitical context to poverty. There’s also a present political context of growing nationalist unilateralism in the west. Both of these seem to be missing from your worldview and from your analysis. And yes, it makes me skeptical (not baselessly IMO) of how you marshal your evidence, which seems much more synchronically contextual. You tell me that “we all agree” that the “human project” involves creating “flourishing, sustainable, peaceful societies in which everyone can enjoy sufficiency, security, dignity and some level of autonomy.” Do we? Who’s ‘we’? Do you think that’s what’s motivating Donald Trump? Vladimir Putin? Viktor Orbán? Bashar al-Assad? Do you really think that’s what the global political economy is all about? “Well, excuse me for defending the interests of the poor” you tell me. “You can’t resist gratuitously quoting a racist comment, as if it has anything to do with what I have said”, you say. It has a lot to do with what you said. I find your position here astonishingly naïve and I think your ahistorical insistence on the primacy of fertility feeds directly if unwittingly into an emerging political context in the west that doesn’t give a damn about the plight of the poor and will be only too happy to impute it to their own cussed fertility without any wider historical or geopolitical analysis. One of the points of my original post was to identify proximal and underlying drivers of social phenomena, and I argued that population and global political economy respectively fitted those boxes. Obviously it’s more complicated than that, but your failure to pick up on this or render it in your analysis seems to me a major weakness.

    2. Developed and developing countries. In your earlier comment you wrote “I have no intention of diminishing the impacts of high resource-consumption lifestyles” but I think that’s pretty much what you do do whether you intend to or not. You added “actually those haven’t got more resource-intensive nor emissions-intensive in the past several decades” which you must surely realize is an entirely irrelevant datum for assessing their impact. In your last comment you wrote “I was countering the idea that the world’s environmental and development problems would disappear if developed countries were magically removed from the planet. They wouldn’t – for many countries, they’d be worse off.” Well, it’s impossible to say really isn’t it? It all depends on the nature of the magic, and of the disappearance, and of what would happen next. Of course you’re right that what’s happening in the ‘transition’ countries is critical, but you seem systematically oblivious to the forces structuring the global political economy, what’s behind them and what alternatives may need to be wrested from them if what you call the ‘human project’ is to succeed.

    3. Fertility and poverty. You write: “Given the mathematical simplicity of population growth reducing natural resources per capita, I would have thought ‘bald assertion’ better fitted the position that denies that population growth generates poverty.” And yet there’s plenty of evidence and analysis from Henry George down to Robert Netting among others that the relationship between population growth and poverty is not mathematically simple – indeed in some (albeit rare) cases population decline reduces resource availability and increases poverty. I’d concede that ceteris paribus there’s usually a positive relation between population, resource availability and poverty. But ceteris never really is paribus is it?

    4. Straw man. If you think that nobody considers population to be ‘the’ problem, you can’t spend much of your time ‘below the line’ in the blogosphere, which I’m sure is very wise. But it’s not so wise if it leads you to neglect the wider political contexts within which analyses of fertility and poverty are interpreted, as per point 1 above. That said, I concede that my dismissal of ‘population control’ policies in my post was probably too cavalier so I will reconsider that.

    5. 16 Gt. You write: “16 Gt is not that much in the scheme of all future emissions”. Good – I think we can agree this point and leave it there.

    6. Population increase and its causes. OK, I now get what you’re saying – but surely the way to characterize it more clearly is not that “global population growth has increased since 2000” but that the amount or the rate of absolute increase has increased. I’m still not sure how significant this is – you say that relative growth rate is barely relevant, but that’s surely untrue because you need to consider the ‘locked in’ dynamic implicit in the existing population and the rate gives you a better idea of trend. Presumably, what’s more important at the end of the day than exactly how to render these historical figures is what the longer-term trends in population and resource use will be. You’re arguing strongly that population control policies, broadly conceived, make an important contribution to those trends. I’d accept that I need to look into that issue more seriously than I did in my offending post, and at some point I’ll do that. At present I’m fairly agnostic about the issue – the more-or-less cross-sectional country level data that you cite does seem potentially suggestive, but it also seems a rather crude basis on which to assert your top-down FP model so emphatically and there’s a lot of potential for confounding in it. You might turn out to be right on this point but I’m not going to take your word for it – especially when you bat away issues of population agency so off-handedly and assert your monocausal explanation so shrilly.

    7. Fertility crash. Global average fertility in 1964: 5.07 births per woman. Global average fertility in 2015: 2.45 births per woman. If you can point me to another time in world history when the global average fertility rate decreased by as much or more in a 50 year period then I’ll accept that my statement “fertility is crashing at a historically unprecedented rate” was wrong. Otherwise I won’t. I accept that there’s a more complex underlying reality. There’s always a more complex underlying reality. But a lot of people I come across seem pretty unaware of the change at all. You’ve convinced me that I should probably take population control policies more seriously than I did in my post. You haven’t convinced me that your population-centric take on poverty and resource depletion is correct.

    • Hi Chris,

      I’m trying not to engage with your ad homonym attacks, because it really doesn’t matter to this discussion who I am. But given that this discussion is about population growth, and I’m trying to be specific in addressing the points you raise, you have no basis to judge my worldview. Let’s stick to the issues of your blog.

      You argued that fertility was declining without any interventions to promote it, and that it would soon cause population to peak and decline, and that we could not effectively do more to influence it, and that we didn’t need to. I am arguing that these are demonstrably false positions.

      1. Fertility crash. The period 1950 to 2015 is not one moment in history. Fertility fell at historically unprecedented rates in the 1970s but did not do so in the past two decades. My central point is that this is a vitally important realisation, and a very valid reason for concern about population growth and efforts to renew attention to it. That slow-down, which the UN didn’t expect, has already added over 2 billion people to the UN’s projected population for the year 2100. See https://www.researchgate.net/publication/305326470_Population_Projections_Recipes_for_Action_or_Inaction

      2. Efficacy of efforts to reduce fertility. My second point, related to the first, is that fertility fell rapidly if, when and where there were voluntary programs in place aimed at getting it to fall – and did not where these were absent. (The rare instances of coercive measures like China’s one-child policy were ineffective as far as I can see, so they played no significant role in the fertility decline.) So when you suggested that no “realistic policy measures … could have been implemented … that could have improved on this fertility decline”, I say that what was implemented in many countries in the 1970s and ‘80s could be implemented in the remaining high-fertility countries, and that would make a world of difference. Ethiopia and Rwanda are demonstrating it today.

      3. Concern is well-founded. We know what happened in the mid-1990s to cause the slow-down: the UN’s International Conference on Population and Development in Cairo, where a concerted anti-contraception lobby painted all efforts to reduce fertility as coercive, and had ‘family planning’ redefined as providing access to contraception only. (Some messaging around child spacing persisted in some places, as a health issue, but not explicitly to reduce family size.) After 24 years of data showing that the ‘indirect drivers’ theories were ill-founded, it should be perfectly legitimate to air the evidence and question the continuation of this policy position without being called a racist.

      4. Fertility and poverty. Whatever the other factors at play, and I have never denied them, there is a very strong association at country level between fertility and growth in GDP per capita. That data is in the paper I linked. (GDP is not a measure I like, but it’s about the only one with sufficiently wide coverage over a sufficient timeframe, and for underdeveloped countries, it does reflect economic betterment fairly reasonably.) So, among the many other factors at play, this one comes through very strongly. There is also a wide literature on the association at household level. It is not a “monocausal explanation” but it would certainly fall into the “necessary but not sufficient” basket. To deny that we need to address population growth, or that expressing concern about it is an attack on the poor rather than acting for the poor, you need to make the case that it doesn’t hamper development. It is not enough to say that there are other factors at play. (Henry George had an ideological commitment to denying any effects of population growth, because he believed that God controlled pregnancies and God’s will could not be bad. His motivations and much of his other analysis are good, but on this point, his logic was awfully twisted.)

      • Jane, if you regard the criticisms I’ve made of your positions and the wider contexts within which I’ve placed them simply as ‘ad hominem attacks’ then I’m done – but I don’t think it reflects well on you most fundamentally as a scholar rather than as a person. I understand the critique you’ve made of my blog post and I think I’ve conceded the points that I needed to concede. But I’m struggling to understand how you can be so determinedly oblivious to other ways of framing the issues involved and to your own dubious presentations of some of the evidence. I think it undermines the parts of your commentary that do genuinely hit the mark.

        So, no more comments from me on this thread but I aim to reproduce this exchange within a blog post next week with some brief introductory commentary. I’ll be interested to read any comments that emerge from that.

      • Dear Jane,
        I read your Chapter “Synergy between Population Policy…” and found it very interesting. Like Chris, I am not an expert who has studied human population growth but I have always considered over-population as the largest driver of environmental degradation. I look at it rather simplistically: over-population leads to greater consumption and every environment has it’s carrying capacity.

        I have long taken for granted the truth of the assumption that “education for girls and economic opportunity for women” led to lower birth rates. It seemed like a rational argument based on my experience. US woman who go to college tend to earn more money than those who don’t, wait longer to marry, and have fewer children. I’m sure I have read this “fact” in the scientific literature. Thus the assumption must be correct! Your paper and the figures in it made it very clear that access to comprehensive voluntary family planning leads to smaller families and better economic outcomes rather than the reverse. It may seem like a chicken and egg issue, but I think you make your case very well that FP is the first component that leads to better economic outcomes.

        I very much agreed with your statement “The low priority afforded to population measures implies that they would compete with other mitigation or adaptation efforts. This is a mistake, since family planning measures are usually cost-negative, saving health and education systems far more than they cost. Hence, they simultaneously liberate resources for other climate change and development measures and reduce the scale of other measures required to meet humanity’s needs.”
        I have always believed that access to good family planning could alleviate many social problems in my country; poverty, crime, and social injustice. I find it ironic that conservative Republicans denounce family planning (because obviously it must mean abortion) claiming that they value the life of the child above all, and then cut programs such as Head Start that are cost effective ways to benefit the child and reduce poverty. For some reason once the child is born conservative Republicans see no responsibility for society to provide any care for the children. Much more logical to build jails for all those criminals!

        I agree with your conclusions that “…without urgent promotion of voluntary family planning, the population projection of SSP1is not possible and “safe” climate change pathways are unlikely. In a world of 11 billion people, let alone 14 billion, considering the requirements for arable land, fresh water, nitrogenous fertilizer and building materials, even assuming 100% renewable energy, net drawdown of atmospheric carbon would require implausible levels of carbon capture and storage. It seems rash to turn our backs on technologies as cheap, reliable and widely beneficial as voluntary family planning in favour of technologies as unproven, costly and potentially damaging as carbon capture and storage.”
        I believe the only reason governments and industry support carbon capture technology over something less expensive such as FP is that they see the opportunity to profit from the implementation of such future technologies (if they can be proven). I believe we will find that carbon capture requires more energy than the energy extracted from burning the fuel.
        Good luck and regards,
        Jody Tishmack

        • I have long taken for granted the truth of the assumption that “education for girls and economic opportunity for women” led to lower birth rates… Your paper and the figures in it made it very clear that access to comprehensive voluntary family planning leads to smaller families and better economic outcomes rather than the reverse.

          I have a third point of view, that I have never seen in the literature, although I’ll echo the disclaimer that I am not an expert on human population growth.

          Rather, I consider myself an ecologist, with college-level coursework and much personal study behind me. In that regard, I consider myself more expert than most in population growth in general.

          What limits human population growth is access to energy. A new electric water pump in a poor village means a woman does not have to breed a water carrier. Symbolic energy storage (through fiat currency) means a woman does not have to breed a pension plan.

          You yourself hint at an understanding of this, when you mention “economic opportunities,” which, for much of the world, means “access to energy.”

          I feel so strongly about this that I have modified Paul Ehrlich’s famous equation: “I = P*A*T”, or, “Impact equals Population times Affluence times Technology.” When I teach Permaculture, I change the “A” term to “Access to Energy,” because isn’t that the root of all affluence?

          By no means am I saying we should ignore the role of family planning. But I think family planning is difficult to implement without some measure of affluence or access to energy or whatever you want to call it.

          This results in a conundrum: if one accepts the Ehrlich equation, it appears that all three terms are mutually dependent, and that reducing any one may mean increasing another. As we slide down the backslope of Hubbert’s Curve, I fear people will once again see the need to breed their slave labour force and retirement plan.

  25. I found this review article very informative. https://academic.oup.com/nsr/article/3/4/470/2669331
    “One of the anonymous reviewers pointed out that the failure of policymakers to react sufficiently to the scientific understanding of global warming is paralleled by a similar failure with regard to scientific knowledge about population trajectories. Family planning policies have been pushed off policy agendas for the last few decades, and the subject of population has even become taboo. There are numerous non-evidence-based barriers that separate women from the information and means necessary to plan childbirths. The total fertility rate remains high in many countries not because women want many children but because they are denied these technologies and information, and often even the right to have fewer children. Access to family planning information and voluntary birth control is a basic human right and should be treated as such by international institutions and policy frameworks. Similarly, there is also an urgent need for improved educational goals worldwide. While these goals are repeatedly supported by both researchers and policymakers, policy implementation continues to be lacking. As a recent report by the Royal Society (the UK National Academy of Sciences) explains, improved education (especially for women) and meeting the large voluntary family planning needs that are still unmet in both developed and developing countries are fundamental requirements of future economic prosperity and environmental sustainability. This again emphasizes the critical need for science-based policies [98,182,184,218,221,222,223,224,225,226,227].32”
    This seems to support Jane’s points. That we’ve neglected family planning and that birth rates will not go down on their own as if often assumed in UN statistics.
    Another point made was this:
    “Rates of deforestation and agricultural expansion have accelerated in recent years with extensive new infrastructure providing conduits for settlement, exploitation, and development.”
    I agree with you Jan that ultimately access to energy is what limits population. Fundamentally this is true especially if we consider food to be the primary source of physical/bodily energy. But in terms of economic activity transportation of goods including energy is a key to expansion of both population and economic activity. A good example is natural gas derived from fracking. Until pipelines and LNG transfer systems are completed the market for gas is limited.
    Transportation history shows that many large cities were first located along waterways because water was key to transportation. In the US railroads opened up the country for economic expansion, followed by the interstate highway system.

    All this is to say that the relationships between energy, population, and economy are highly complicated and not given to easy correlations. Even a brief dip into this pool convinces me that I’m in over my head!

  26. Pingback: The Population Problem Problem - Resilience

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