The population problem problem

A while ago I wrote a post probing critically at the idea that human population levels were at the root of our contemporary environmental problems. It prompted various critical responses in turn, including this one from Alan Ware and Dave Gardner of World Population Balance that’s only just come to my attention. They published it so long ago that I suppose the moment to engage with it has probably passed, except that it’s helped me clarify a few thoughts – as has a recent article by Meehan Crist in the London Review of Books1. Since the issues involved are still very much with us, it seems worth wading into the population question once again, this time through the lens of the critique levelled by Ware and Gardner (henceforth WG) at my original post.

I mischievously titled that original post “Population – what’s the problem?”, not necessarily to suggest that population isn’t a problem but to question what kind of problem it is. On this score, WG have no doubts – for them, it’s an “existential problem”. They proceed to substantiate this, as do many analysts on the topic, mostly by asserting very emphatically that it is a problem, sometimes invoking the emphatic assertions of others, especially those most respected of others, ‘scientists’. These scientists include the World scientists’ warning to humanity and other works co-authored by Eileen Crist. Seems like you need to be called Crist to weigh in on this debate.

Ah well, I almost qualify – and for my part, notwithstanding all these assertions, I’d say that inasmuch as population is a problem it seems to me a secondary problem that’s derivative of other, deeper ones. But perhaps what’s of most interest here is not who’s right or wrong so much as how we frame the issues. You can frame them in such a way as to suggest that population indeed is the fundamental problem, or you can frame them otherwise. These different framings invoke different understandings of how the world operates and point to different policy or political conclusions. I think that WG’s approach, like most approaches that frame ‘over-population’ as the fundamental problem, points to policies that will have little impact on the resource depletion, species extinction, poverty and climate change issues they (and I) care about, and to a fanciful and troubling politics. Of course, this itself is a framing that others will no doubt question – but at least then we get closer to the issues dividing us.

One of WG’s main points of substance is that choosing not to have a child is, in a ‘developed’ country, the most effective way of reducing one’s carbon emissions. Citing a study from Lund University, they say that this is over seven times more effective than various other ‘green’ measures (like not flying) combined. That study draws on an earlier one2 which, if I understand it correctly (and it’s possible I don’t), assumes that carbon emissions will be fixed in the future at 2005 levels – the two studies then effectively attribute proportionately to parents in a generation G1 all these fixed-rate future emissions generated by all subsequent generations G1+n in an exponential decay function.

Well, no doubt there’s a logic to doing that. After all, if nobody had any children, then human impacts on earth systems would soon cease, so indeed all future impacts in some sense are attributable to parents. Following that logic, it’s hardly surprising that the choice to have a child weighs heavily on an individual’s impact in the study results. But to me, it’s a strange logic. Though it’s no doubt intended to inform decision-making at the margin in any given generation, to avoid multiple counting it surely must assume that the emissions and by implication wider behaviours of all G1+n generations are zero, according them no responsibility of their own, but only their parents or grand+ parents for birthing them or their forebears.

Conceptually, this approach rests on a strong methodological individualism – everything that happens must be regarded as only the sum of individual choices. Historically, it’s anachronistic, because it’s clear that if humanity is still around in a century or two then one way or another it won’t be burning significant fossil fuels, causing further major species declines and so forth. And spiritually and philosophically, the approach seems like a kind of inverted original sin whose logic surely terminates in the notion that humans should seek voluntary extinction through non-procreation to avoid the weight of later generations’ trespasses. The Lund authors note that none of the school textbooks they consulted mentioned having fewer children as a way to reduce emissions – a good thing in my opinion, since confusing the fact that a person has impacts with the idea that a person is an impact has potentially disastrous political consequences.

Let me propose another approach, which I think is suggested in the graph below. This plots global population, energy use, CO2 emissions, and real GDP year on year from 1972-2014 as ratios relative to the base year of 1971 (I calculated this from the World Development Indicators, which only have complete data for these four variables from 1971-2014).

The graph shows the three other variables of interest rising relatively faster than population. GDP shows the greatest relative increase – more than energy use or emissions, possibly suggestive of the decreasing energy intensity of the economy (‘relative decoupling’), or of the increasing dematerialization of our modern, fictitious money economy. But both energy and emissions are still rising in absolute terms, faster than population. The kink in 2008-9 of course indicates the economic crisis of those years, which was immediately reflected in lower energy use and lower emissions, but unsurprisingly was not reflected in a lower population.

I think the graph is prima facie evidence that there’s a dynamic of growth in our modern global society which is not fundamentally driven by, or necessarily responsive to, population growth. And given that it’s generally reckoned we need to reduce emissions to net zero by around 2070 to avoid catastrophic climate change, I’d also suggest that seeking population reduction isn’t the priority place to look. Not that we shouldn’t look there at all, as WG mistakenly accuse me of saying, just that it’s not the priority place to look. A similar point is made in a paper by Corey Bradshaw and Barry Brook, who state “over the next century at least, our largest and most immediate gains in sustainability will necessarily come from reductions in per capita consumption, whereas the benefits of fertility reduction will improve humanity’s prospects cumulatively over the long term.”3

Bradshaw and Brook’s fingering of consumption gets closer to the issue, but I’d suggest the real force that underlies the growth dynamic depicted in the graph and that overdrives population increase – the force I’m tempted to call the elephant in the room that nobody wants to talk about – is the global capitalist economy, as I mentioned in my original post. Increased per capita carbon emissions and energy use above population increase are the material trace of a capitalist growth dynamic.

If those energy and carbon trend lines were just the dependent outcome of consumer choice summed across our human billions, as WG suppose, there’d be a better case for emphasizing fertility reduction. But there’s a systemic logic to capital increase that goes beyond individual consumption decisions. In a capitalist system, capital needs to grow – that GDP line pretty much has to follow the course it does, and the emissions and energy lines pretty much have to trail after it.

Therefore, I question the notion that reduced fertility equates to reduced impact. It feels right, because if you choose not to have a child then, very tangibly, you’re aware of the food that this non-person is not eating, the journeys and flights they’re not making and so on. Yet the capitalist economy still has to grow. It’ll just have to find another way of doing it than monetizing your non-child – and it does.

I think WG effectively admit this when they write “The UN estimates that by 2050 we’ll have to increase food production 60% over 2009 levels in order to meet the demands of our swelling population.” They don’t give a citation, but I assume this is a variant of the ‘70% food increase by 2050’ factoid that’s been doing the rounds for years. Since even the highest projections of global population increase over the 2009-2050 period suggest it’ll be less than 60%, you could be forgiven for wondering where these 60% or 70% figures come from. The truth is they’re pretty misleading. All the same, in the unlikely event that the global capitalist economy is still happily growing by 2050 (at which point it’ll have to be over twice the size of today’s global economy), it’s possible that humanity indeed will be ‘demanding’ 60-70% more food by value than in 2009, because the ability of all that extra global wealth to command the production of beef, salmon, prawns, tuna, coffee, wine, palm oil and so on will be prodigious. One study has estimated that the highest additional demand for land globally by 2030 breaks down reasonably evenly between cropland, industrial forestry, biofuel production, grazing, urban expansion and land degradation4. A good deal of that, I’d suggest, is driven less by ‘the demands of our swelling population’ and more by the demands of our economy to swell.

WG’s position on all this strikes me as inadequate. They write:

“We’ve so far NOT demonstrated a willingness to consume less and reject the worship of economic growth in the interest of stabilizing the climate or preventing further destruction of ecosystems. This doesn’t mean we should give up on this solution. But it also doesn’t mean we should ignore a solution we HAVE demonstrated a willingness to do — choosing smaller families.”

No, we shouldn’t ignore it. But if my framing above is correct, then only directly rejecting boundary-busting economic growth can do the heavy work of lowering humanity’s ecological impact. Choosing smaller families doesn’t cut it. And here, I think it’s necessary to probe further into the ‘we’ that WG say are unwilling to consume less. It’s inherent to the nature of the growth-seeking capitalist economy to co-opt or destroy other, non-growth forms of economic organization, whether this takes the form of planning laws, property prices, land expropriations or the Bay of Pigs invasion. Uneven development is also inherent to the growth economy – it requires poor people and poor countries, even if it holds out the promise of making them a little less poor. The result of all this is that few of us have any option but to participate in the capitalist growth economy. And if we have to participate, who wouldn’t choose if they could to be a beef-eating wine drinker rather than a rice-eating helot? WG invoke a story of ourselves as consumers, wanting more stuff. And, sure, if that’s the only route to provisioning ourselves that the political economy allows, it’s not surprising that ‘we’ mostly want to be as prosperous a consumer as it’s possible to be. But this doesn’t begin to tell the story of what human lives are about or where our willingness might take us.

In the longer run, as Bradshaw and Brook quoted above suggest, there’s certainly a case for promoting reduced fertility. However, I’m doubtful it will culminate in this cornucopia that WG conjure up: “An average family size of one-child per couple for 100 years could lead to what some experts posit as a sustainable population of around 2 billion people living at a European standard of living.” No society has yet managed a modern European standard of living without (1) a vast and unsustainable fossil-fuelled energy economy, and (2) a history of colonial expropriation and neocolonial labour exploitation to the disbenefit of other non-European people living at lower standards of living. This positing of the experts surely belongs in the realms of idle speculation.

One of the ironies of the whole overheated population debate is that actually there’s not much disagreement on the policy practicalities – it’s widely accepted that everyone should be able to have voluntary control of their own fertility. But that’s already pretty much the reality in the rich, low-fertility countries that are largely driving the ecocidal global economy. Where these interventions are most needed is in poor, high-fertility countries that largely aren’t driving it – though it’s further complicated by poverty traps that encourage high fertility. In these contexts, WG’s world of just two billion people, living extravagantly consumerist lives of the modern European variety, and promoted by an organization that claims “overpopulation” is the root cause of poverty, all starts sounding slightly creepy to me. As Meehan Crist puts it:

“Listen closely to rights-based strategies to reduce carbon emissions through increased access to contraception and family planning. These strategies almost always involve black and brown women in developing countries having fewer babies. There is, of course, an unmet need for reproductive care and birth control in these countries, but we should be deeply sceptical of climate solutions that place the burden of solving the problem on women’s bodies, particularly the bodies of poor black and brown women, while demanding very little of those who actually caused the problem.”

Indeed, solving the global problems caused by humanity – and mostly by a small subset of it – is more than a numbers game. Which is why I see little merit in WG’s question to me – “Is he arguing for us to stabilize our population at today’s totally unsustainable level of 7.6 billion?” There’s no cutoff point or carrying capacity at which human numbers suddenly become ‘sustainable’. There are people, there are impacts, and there’s a relation between the two, which is fuzzy at best. It’s unlikely that the human population would have reached 7.6 billion in the absence of a modern global civilization that strains the planetary capacity to sustain it, but it doesn’t necessarily follow that a population of 7.6 billion is inherently ‘unsustainable’. It depends what we’re trying to sustain. If, as I’ve long argued here, it’s small farm societies of widely shared land access oriented to skimming their local ecological base, then we could sustain a lot more people than seems likely under present extremes of global wealth and poverty. Undoubtedly, we’d be in a better position if the population were smaller – particularly the population of the richer countries. Undoubtedly, voluntary fertility reduction is in principle a good idea. But it’s not a high-impact way of reducing humanity’s high impact, and it potentially leads us into political mischief if we claim that it does.

Meehan Crist points out in her article the enthusiastic embrace of carbon footprinting by the fossil fuel companies. While lobbying hard to keep extracting, and dragging their feet over climate science, the narrative that environmental impact is a matter of individual lifestyle choice in which we all need to do our bit suits them well, helping them to duck their own responsibilities. Ultimately, though, the responsibility rests at the level of an economic system which encourages this phoniness. Even so, as well as the phoniness, I feel the force of that personal responsibility narrative. As – full disclosure – a parent of four, I’ve long wrestled with my personal culpability in this area, and the many others in which as a wealthy westerner I impact the biosphere. Maybe someone reading this will conclude I’m irredeemable, and this post mere self-justification. Yet before I was a parent I was an anthropologist, and like most of my tribe I find the idea of emergent systems, not methodological individualism, a better fit with how the world works. So while as individuals, as consumers, as parents or as non-parents, we agonize and sermonize over our own and others’ lifestyle choices, the oil companies will keep lobbying, and the GDP and emissions lines will keep tracking upwards until we reach a point of reckoning when the size of the human population or how many children anyone has will be the last of our concerns.



1. Meehan Crist. 2020. ‘Is it OK to have a child?’ London Review of Books. 5 March.

2. Paul Murtaugh and Michael Schlax. 2009. ‘Reproduction and the carbon legacies of individuals’. Global Environmental Change 19: 14-20.

3. Corey Bradshaw and Barry Brook. 2015. ‘Reply to O’Neill et al and O’Sullivan: Fertility reduction will help, but only in the long-term’. PNAS 112, 6: E508-9. (My thanks to Jahi Chappell for this one).

4. Eric Lambin and Patrick Meyfroidt. 2011. ‘Global land use change, economic globalization and the looming land scarcity’. PNAS 108, 9: 3465-72.

74 thoughts on “The population problem problem

  1. A thoughtful, useful post, Chris.

    I often get the population question after talks I give on global change and sustainability (in which I do not mention population). My stock answer parallels your point very closely: It’s a thing, but not the main thing. This post is helpful in fleshing out that notion. In particular, your data depiction is compelling.

    Question: You’ve made the statement “Uneven development is also inherent to the growth economy – it requires poor people and poor countries…” Sounds right to me, but this is a particular argument I’ve not come across before in quite this articulation. Can you point to a fleshed-out version?

  2. Excellent as usual, Chris.

    It seems worth noting as well that in the Vatican City of capitalism that is the US, there are occasional mews of concern over what will happen if our population growth slows too much—how will that affect GDP and growth, oh my? Almost any mainstream outlet that talks about this will at least bandy the idea of what can be done to address or forestall the US population shrinking… this is all clearly capitalism-driven reasoning that motivates against decreasing consumption OR population. Surely further evidence of your point—the idea that we might need to argue with US capitalists over population degrowth just as much as they want to argue about GDP degrowth points to which may be the more fundamental issue?

    PS On a purely egomaniacal level, I’m a little disappointed not to see you repurpose my “population is not a bull in a china shop but rather a menagerie in a china shop” 😉

  3. …Just when Nicloas Maduro is urging Venezuelan women to have at least 6 children! As one of 10 children myself my (European) parents had a lot to answer for.
    I agree about the elephant in the room; it just seems an insurmountable obstacle.

  4. Chris, as you know, I have been an active part of population arguments here. As you also know, I am your greatest fan on Peasant Agrarian Populism. And on the whole, you are one smart fellow, and I love reading your thoughts. I have been less active in the comments here because I got a job job sort of job, but I still read every post the day it comes out.

    You say many smart things in this post, but I remain a little chafed. I am somewhat reminded of this irritating meme— https //tinyurl com/badmickeymeme (colon and period needed in the gaps)

    To paraphrase, Donald says, “2+2=4.”
    Mickey replies, with great dunder, “Donald, you simpleton! Can you not see that it is 2 that is the problem, not 2, as knotheads like you idiotically believe?!?”

    So I am chafed at your early discussion of framing. “You can frame them in such a way as to suggest that population indeed is the fundamental problem, or you can frame them otherwise. ”

    I think what the conversation lacks is a clear statement of the problem, and that is what framing obscures.

    A focus on framing allows for ecologically ignorant statements such as Mickey’s, that humans can be a positive impact—and therefore more humans could blast through the orgasm horizon into the singularity of Mars colonized by brains in jars.

    Virtually all conversations are one side or the other trying to position their frame as the The Truth. Population is all that matters. Consumption is all that matters.

    Neither are true, and so most normal people simply tune out, uninterested in wasting their day discussing obvious bullshit.

    Population is not a derivative of a deeper problem, it is simply a number in an equation. We see the results of the equation all around us. If we want to change the outcome of the formula, we can go back and change any number in the equation.

    Which number we focus on reveals a lot—the deeper problems, the framing.

    If what you focus on is poor, brown people, you might be just a racist.

    And if what you care about is environmental impact, then the consumption of energy and materials by the rich, mostly white nations should be your target.

    The formula tells us there are many ways to do this:

    We could consume less. If we do this, more of us could consume less to stay at the same level of impact.
    We could consume more efficiently. The same number of us could consume efficiently and lower our impact. A higher number of us could consume more efficiently to stay at the same level of impact.
    We could control population. This would allow us to consume the same amount and still lower impact, or consume even more and stay the same.

    Controlling rich world population is not free of racist opportunities. For example, we could allow “Old Stock” whites to keep having children, but not let in any new immigrants—after all, people who move from a low impact country to a high impact country raise their impact, which is bad for the exosphere.

    All of these things are options.

    And, as you strongly point out, some of them are likely precluded, because of the imperative of growth under capitalism. So, if we want to consume more efficiently, we must first smash capitalism.

    This is a more nuanced take than the Bright Greens of the world can understand. They seem to think if we use LEDs to light our homes more efficiently, we will just stop there.

    That is not, however, how most of human history has played out, as you know. As we have created efficiency, we have used the new surplus to do more. Now we have LED lights bejewelling every nook and cranny.

    But this is the derivative effect. This is a human dynamic contained within the formula, not an effect of the basic ecological dynamic that population * consumption = impact.

    As you say, “There are people, there are impacts, and there’s a relation between the two, which is fuzzy at best.”

    But I am also dissatisfied with blaming only the effects that are derivative of our particular culture, like growth-imperative capitalism.

    If our only real lever is to smash capitalism, does that mean we should do nothing until we can smash capitalism?

    I think capitalism is going to be like the Berlin Wall. One year it will seem as old and immovable as the mountains. And the next year it will be gone (give or take a few years).

    In those immovable years, I don’t think it is a bad idea to try to reduce consumption, to try to make production more efficient, and to try to lower the population of the highest consumers.

    I know these conversations are difficult, but I always prefer to have reality based conversations.

    You and I both support greater equality for the majority of the world exploited by the colonialism. But in this world, that means we should cheer when everybody gets a private car, and that means billions of people are multiplied by the impact of private automobiles. That would be an ecological evisceration.

    And yet to try to suppress poor people so their impact doesn’t rise is…racism?

    I would rather have a conversation about racism than tie myself in logical traps trying to prove population doesn’t matter. Population is a number in a formula.

    In an effort to not ramble too far afield, I wasn’t going to touch on this, but your last paragraph is a good done.

    “Conceptually, this approach rests on a strong methodological individualism – everything that happens must be regarded as only the sum of individual choices.”

    “While lobbying hard to keep extracting, and dragging their feet over climate science, the narrative that environmental impact is a matter of individual lifestyle choice in which we all need to do our bit suits them well, helping them to duck their own responsibilities. Ultimately, though, the responsibility rests at the level of an economic system which encourages this phoniness.”

    The oil companies have blamed 7 billion individuals—yes 7 billion, not the billion or so of us that actually use lots of fuel.

    But this continues the old enlightenment error that we actually choose our behaviours.

    Everything that happens is the sum of individual behaviour. But behaviour mostly arises reactively—say in response to the systems, lobbying and propaganda from oil companies. Not from choice.

    • “Population is a number in a formula.”

      As I recall, Chris addressed this in an earlier post. If the formula involves an aggregate consumption that’s divided up evenly to give a per capita amount, then it’s an oversimplification (convenient for the bigger consumers).

    • “more humans could blast through the orgasm horizon into the singularity of Mars colonized by brains in jars” – omg, Ruben, you just destroyed the Burning Man set in one sentence.

      In regard to your last point, covid-19 is reshaping our choices on a massive scale, will it simply cause some short-term volatility in the stock market or will we actually learn something?

  5. I see this differently than a question of population or consumption being the root, or primary leverage point to transition to sustainability. They are two sides of the same coin. I see it as simply a species utilizing an energy source, with the resulting population increase. Population and consumption are in a positive feedback loop, enabled by our cleverness.

    The human ability to make tools, develop technology has unleashed fossil energy, which has enabled us to hugely increase calorie production, which along with some basic public health measures we figured out ( germ theory of disease!) resulted in the population explosion. When the fossil energy declines, so will the human population, back to what the sun and photosynthesis can support.

    Sure, we can reason, extrapolate, imagine solutions or alternate futures, but can we consciously, intentionally shut off the oil spigot and begin a smooth glide to a lower energy culture? I don’t think we can.

    Capitalism has created inequity and immoral systems, but it kind of proves the point that the system best able to exploit a resource will prevail (Until conditions change).

    Unless global governance were to happen ( benevolent and forward thinking, of course), I think the concepts of maximum power principle and game theory tell us that if the EROEI is there, someone will exploit the resource.

    Empires of the past have often overshot the local carrying capacity, and we’ve done the same, it’s just that we’ve “cheated”, by borrowing from the past and the future to far outstrip the planetary ability to provide.

    This sounds rather bleak, but it just looks like a thermodynamics driven emergent behavior, and not sure we can smooth the decline and avoid the Seneca cliff.

    I hope I’m wrong, but culture and political structures seem like just an overlay with minor impact to the main operating force at play. If I was in a country where the unfolding crisis was more acknowledged, maybe I’d have some hope, but at this time, I just try to focus on my individual acts, and move in the right direction as best I can.

    I think the best case future will look something like a small farm future. Getting there is the question.

  6. Thanks for the comments. I’ll try to work through them, in order.

    @Robert. Thanks for that. Of course, I’m tempted to say that the best exposition of uneven development is in my forthcoming book! But the classic framing was by Eric Hobsbawm in ‘The Transition From Feudalism to Capitalism’ edited by Rodney Hilton – and also Immanuel Wallerstein’s ‘The Modern World System’. I’ve found Henry Heller’s book ‘The Birth of Capitalism: A 21st Century Perspective’ a very good overview of all the subsequent debates. The Davis book mentioned by Jahi and Jake is also good. And of course there’s Walter Rodney’s ‘How Europe Underdeveloped Africa’.

    @Jahi. Interesting points – agreed on the capitalism/population conjunction regarding declinist fears. I do feel there’s a tricky social policy dimension to strong fertility-reduction policies in terms of ageing societies, despite WG’s scoffing. It’s not a sufficiently strong one in itself to weigh against such policies if they were inherently effective, but if they’re not… And please consider your ‘menagerie in a China shop’ idea duly repurposed! If I didn’t mention it, it’s probably because it’s meaning went a bit over my head. But if you’d like to expound on it, the floor is yours…

    @Jake. Thanks for giving the folks on here an insight into just how joyous our family Christmases can be. As to my point above about my culpability in producing offspring, I want you to know that I love you very much, yours Dad x

    @Philip. Yes, as our various crises intensify I think we’ll increasingly see all sorts of morbid and competitive politics, and a lot of them will be dressed up in populationist rhetoric – whether it’s the ‘white replacement’ thesis of the far right, nationalists urging patriotic families to outbreed their rivals or, dare I say it, environmentalists urging people to stop breeding in order to preserve ‘European standards of living’.

    @Ruben. Congratulations on the job! There are many things we agree on, but indeed this isn’t one of them. In terms of framing, you seem strongly wedded to the idea that Impact = Population x Consumption, or some variant thereof. For those who find that a persuasive framing, then clearly anyone who tries to argue that population doesn’t matter would be tying themselves in logical traps. But, as I outline above and elsewhere, I don’t find that a persuasive framing, and I don’t think there are logical traps in my argument – conceptual assumptions or empirical errors are a different matter. Just to be clear, I don’t suggest that population doesn’t matter, nor am I arguing that the problem is ‘consumption’ – the population x consumption idea may seem obvious, but I’m arguing it’s wrong, or at best a derivative framing of the underlying issue. There’s a danger of talking past one another unless we can find common ground for appreciating the framing assumptions – and I think I’ve already said what I want to say about those above. So, keeping it brief, I’ll just comment quickly on four of your points.

    (1) A clear statement of the problem in a sentence: our present global political economy compromises human wellbeing and earth systems stability.

    (2) “I don’t think it is a bad idea to try to reduce consumption, to try to make production more efficient, and to try to lower the population of the highest consumers.” Nor do I, but nor do I think they’re the most (cost-)effective ideas.

    (3) “If our only real lever is to smash capitalism, does that mean we should do nothing until we can smash capitalism?” No, but we have other levers. One of them is to try to build local autonomies from capitalism. In some situations, one way of doing that is to have a lot of children.

    (4) “You and I both support greater equality for the majority of the world exploited by the colonialism. But in this world, that means we should cheer when everybody gets a private car”. Only if we agreed that equality was the cardinal goal, such that anything promoting it must be supported. And even then, we might prefer to cheer when anybody no longer had their private car. But I think the goal of equality must be complemented by other goals. Amartya Sen’s notion of equality in capabilities for flourishing is as good a shorthand as I can think of for succinctly capturing the ones I have in mind.

    (5) “ecologically ignorant statements such as Mickey’s, that humans can be a positive impact”. I don’t think humans or anything else can be regarded as having inherently positive or negative impacts in the abstract. You always have to ask who’s judging, and by what criteria.

    @Steve L. Agreed – population can certainly be a number in a formula. The question is whether the formula is illuminating.

    @Michelle. That’s a question I’d like the benefit of hindsight on! Hopefully the latter.

    @Steve C. Much to agree with there, which touches on the topic of my next post. Where I might disagree (but might not) is the idea that if the EROEI is there, someone will exploit the resource. One datum is that fossil fuels were first exploited industrially about 2000 years ago, but didn’t lead to earth systems breakdown until recently. Perhaps the limiting case is if someone exploits the EROEI embodied in the world’s nuclear arsenals. Why? Because it was there! I have a feeling that game theory and suchlike are congenitally inclined to this view, because the cultures that emphasize EROEI exploitation are the ones that have articulated game theory.

    • One datum is that fossil fuels were first exploited industrially about 2000 years ago, but didn’t lead to earth systems breakdown until recently.

      Depends a little on what you mean by “industrially”. My understanding is that fossil fuels were used almost entirely for heating purposes, used little differently than wood or peat, until the invention of the steam engine. It was the ability to tap the huge reservoir of fossil heating fuel for the creation of motive force that allowed for rapid growth in industrial manufacturing, transportation and labor substitution in farming and other high-labor jobs. The Haber-Bosch process completed the industrialization of agricultural nutrient production and facilitated a huge growth in food production, allowing population to increase even more rapidly.

      I also second Steve C’s point that economic and political structures are less important than the development of a high energy industrial civilization. Unless you are defining the development of industrial machinery itself as “capitalism”, I see no way to pin the blame on what most people would call capitalism (an economic and political system in which a country’s trade and industry are controlled by private owners for profit, rather than by the state).

      A high energy industrial culture could be developed by any number of political structures, including those that didn’t use markets or even money. Perhaps capitalism is more effective in maximizing energy thoughput and building machines, but command economies have clearly been able to succeed in rapid industrialization (see USSR).

      I think it would be useful to imagine what the world would be like now had there been no fossil fuels to be discovered. Would we have been able to make a world like we have now without them? I can’t see how. Yes, it was possible to make limited amounts of iron and steel with charcoal, but much of the world was already running out of trees by the time of the industrial revolution. That revolution could have never happened without coal.

      Then imagine whether capitalism existed anywhere in the world prior to the industrial revolution. I think that medieval merchant and construction guilds would qualify as “private ownership of the means of production”. They certainly weren’t “owned” by governments and some guilds became powerful enough to push around the Catholic Church. I know that some would not call these “early capitalists” practitioners of true capitalism, but they are still evidence that a form of capitalism could exist without industrialism.

      While capitalism may be efficiently facilitating the destruction of nature, we could easily find numerous other ways to do so. It’s not so important how we’re organizing the destruction, but that we’re doing it with energy and machinery.

      • Joe, this is all highly relevant to my next post so I’ll mostly hold fire until then. My understanding is that coal was used to smelt iron in China over 2000 years ago, so I think it’s worth asking why it didn’t immediately lead to an industrial revolution – and the most plausible explanations for me have to do with economic and political structures. But I’ll expand on this shortly.

  7. I keep coming back to Paul Erlich’s equation: Impact equals Population times Affluence times Technology.

    You can vary any term in the equation to address the problem, but they all have an impact, and they are all interlocked.

    I agree that addressing population in third-world countries is not particularly effective, because they are not affluent. Every time some well-meaning celebrity adopts a little brown baby from a poor country, the impact of that baby goes up by a factor of perhaps a hundred.

    And yet, I fail to see a viable world in some Smajian future of eight (ten? twelve?) billion neo-pesants, all working small farms!

    Right now, there’s roughly 4-5 acres of land per person on Earth.

    “Hmmm… not bad,” you might think, “I could live on 4 acres.” But that includes deserts, mountains, tundra, and Antarctica. From what I’ve read, the arable surface is probably less than a tenth of that. In fertile areas, a person could eke out a living on 0.4 acres, but even that figure includes areas that are today dependent on irrigation and artificial fertilizer.

    So sorry, Chris, but I don’t really see your view that population is not a problem, unless I’m misunderstanding you.

    I come back to Erlich. All three terms are important; all three must be addressed.

    • Jan, I’m not arguing that population isn’t a problem. I am arguing, though, that policies geared specifically to lowering fertility will, in themselves, have little effect on humanity’s planetary impact. Policies geared specifically to lowering the impacts are a better bet – but these would involve a complete overhaul of the global economy. Ehrlich’s equation is misleading. In fact, it’s not an equation, and it doesn’t provide a plausible account of reality in the way that an equation like Force = mass x acceleration does. In the latter case, the equation tells us that if we halve the mass then, necessarily, the force is halved – and this is borne out by real world observation. Ehrlich’s equation likewise suggests that if we halve the human population then, necessarily, human ecological impact is halved. What I’m arguing is that this isn’t true, and we need to look for deeper explanation. Still, I agree with you that a world of 12 billion neo-peasants is unlikely to be viable. This isn’t something I’m advocating. I probably would suggest, though, that it’d be more viable than a world of 12 billion capitalists and workers.

      • It’s important to remember that Ehrlich’s formula deals with aggregate numbers for Affluence and Technology. Thus each human in the Population variable is assigned the worldwide average for affluence and technology application. So yes, for this formula, if population numbers are halved, aggregate impact is halved.

        Of course, using aggregate numbers disregards the extreme variability in individual impact found around the world. Reducing the population of sub-Saharan Africa by half does virtually nothing by way of reducing global impact. Reducing the population of the US by half would do a lot. I think you are right to focus on the causes of this variability, but I also think that time is far too short for any program of voluntary correction of the causes of excess affluence to work. Maybe Covid-19 will do some involuntary correcting.

        And if the world actually de-industrialized, and virtually everyone became agrarian peasants, we wouldn’t need to worry about population at all. Natural ecosystems would remain healthy (except in self-limiting local areas), population would be controlled by fluctuations in the available food supply and a Malthusian equilibrium would be obtained. Problem solved by a small farm future.

      • Well… part of what I’m arguing is that we should stop thinking about ‘impact’ as a dependent variable that’s directly associated with population as an independent variable. I think it’s helpful instead to think of the present political economy as an entity in its own right, pursuing the overriding goal of its own growth. There are various ways it can do that, of which fostering population growth in both rich and poor countries is an important one, but not the only one. Reducing population and/or its growth is one way to try to reduce impact, but without tackling the political economy’s imperative to growth head on I think it will have minimal effect on environmental impact, whether population reduction occurs in rich or poor countries.

        At some point soon, the growth economy will come to an end. At that point, in theory the fewer people who are around the easier it will be to transition to a non-growth economy. But in practice, I think that the more we’ve inculcated in ourselves the mindset that the numbers of people are a problem, the more at that point we risk unpredictably violent transitions that will be in few people’s (and perhaps few organisms’) interests.

        Regarding the equation, to me it becomes little more than a truism or a tautology in the aggregate. It’s not saying much more than Impact = Impact per capita x Population. Why not simplify the equation: Impact = Impact ?

        Population, affluence and technology may drive impact, but what’s driving them? In any case, impact growth is exceeding population growth.

        • The formula is not a tautology, but it is very simple. It’s basically saying that affluence = impact, which is difficult for many people to accept, particularly the affluent.

          Population, affluence and technology are driven by energy consumption, particularly population and affluence. At present, that means fossil fuel consumption. Greatly reduce fossil fuel consumption and impact is greatly reduced.

          Perhaps capitalism creates more incentive for energy consumption than other types of economic structures, but I doubt that there will be any way to reduce fossil energy consumption dramatically when most people live in cities, regardless of how they get their needs met.

          So, I would put more emphasis on de-urbanization than getting rid of capitalism. We could get rid of capitalism entirely and we would still have an impact problem if most people still live in cities. If everyone lived in the country, we wouldn’t need to worry about capitalism at all.

          • Chris, I agree with every part of your response (except about framing) and yet you remain stubborn and dismissive about the formula as a clarifying tool, and I have never understood why.

            It is not a tuatology, population can’t be ignored. In order to ignore population you must be able to show any population anywhere that does not impact its ecosystem by its presence. This is not a judgement–everything eats and everything shits. That has impact independent of whether we think that impact is good or bad.

            Especially with humans, there is a cultural lower bound–the presence of a human being creates the impact of feeding them, clothing them, housing them, giving them roads to drive on and hospitals to visit. The much higher state contribution to impact is why it would be so helpful if we lowered rich world population.

            (Yes, I don’t think that is likely to happen, and yes I agree there are other levers to pull. I just don’t think we should ever have conversations based on lies, like population is not part of the equation. I also don’t think we should have conversations about how we can maintain this lifestyle without fossil fuels, or about how vertical farms can feed the world. Beginning with a foundation of truth is necessary, or it corrodes the conversation.)

            So I don’t understand why you are being coy with the formula. Especially with the more detailed formulas such as Jan presented, the affluence, impact, technology, whatever, are all there. So, if you reduce the poor half, you are left with the rich half, with all of the much higher numbers of their affluence, impact technology etc.

            In fact, this is exactly like F=MA. Any creature has impact from consumption. A plague of locusts has different impacts than one locust. The formula is a framework to show us where to look, and so we can even increase the impact numbers to account for non-linear ecosystem impacts caused by a swarm of locusts over simply many locusts.

            Nobody who does Life Cycle Analysis or Ecological Footprinting would suggest that cutting population in half would cut impact in half. In fact, it is more accurate to say the Ecological Footprint numbers are built UP from thousands of Population Consumption formulas, and you could pull any one of them out to look at it.

            In fact, this has been done down to the scale of Vancouver BC. It is simply strange to look at an Ecological Footprint of Vancouver and then complain that we should reduce the population of brown people.

            Again, this is a law, like F=MA. Everything eats, and what they eat can be measured. More things eat more stuff. This is not framing, this is fact.

            The framing is much further down.

            Humanity is just a subset of the ecosphere. Western culture is a subset of humanity. Capitalism is an economic subset of Western culture.

            So when you look at the formula:
            Impact equals
            Population times
            Affluence times

            It would be written out something like:
            The production of land and ocean area and the waste sinks of land, ocean and atmosphere
            How many people from where (framing)
            What socio-economic group do they belong to (framing)
            What technologies do they use (framing).

            The levers you suggest we pull—which I agree with—are human constructs completely contained within the several subsets down from the ecosphere.

          • @Ruben,

            I just don’t think we should ever have conversations based on lies, like population is not part of the equation.

            “Lies” is way over the top, Ruben. The word implies that Chris is saying something he knows is false. He may be mistaken in minimizing the importance of population, but I am certain he is not “lying”.

          • @Joe and Ruben –
            Let’s recall that “lies” can be used as both noun and verb. A material misstatement of fact is a lie as a noun. To act in a manner to deliberately misstate the truth is a lie as a verb.

            For the purposes of the debate it seems to me we’re trying to establish the truth, and in so far as we might each have some claim upon a true vision of reality we shouldn’t be accusing some of lying.

            I recall seeing an argument once about how some human activities impact the numbers of other species (cost was a parameter in point). At the same conversation I missed the suggestion of how human activities impact the total biomass on the planet surface available to all species. Thus there are value judgements on display. How can one’s value of a particular resource be considered a ‘lie’?? One’s defense of their behavior could be built upon a lie, but that judgement remains to be established by a jury of the factfulness in question.

  8. @Ruben, Interesting comments, thanks. But I don’t think you can plausibly say in almost the same breath that I=PAT is exactly like F=ma and then say that nobody is arguing that cutting population in half cuts impact in half. If nobody is arguing that, then I=PAT is wrong, because that’s exactly what the formula tells us.

    You say I’m dismissive about the formula as a clarifying tool – if I am, it’s because I don’t think you need to use formulas as clarifying tools, and if you do they’ll probably be misleading, because formulas should be universally true within their frame of reference. As a clarifying tool, I’d have no problem with the statement “Human impacts on the environment are a complex function of, among other things, population, affluence and technology – though opinions differ on the fundamental levers for reducing impact”. I don’t dispute that population has an impact on impact. I do dispute that I=PAT adequately describes it.

    Maybe it’s instructive to look at the Wikipedia pages for the formulas I=PAT and F=ma. The former cites mathematician Neal Koblitz criticizing Ehrlich and calling equations of this type ‘mathematical propaganda’ and it has a whole section on criticisms of the formula. There are no parallels to that on the page for F=ma.

    If we’re applying the formula to ANY kind of ecological impact – such as your examples of eating and shitting – then, sure, the P term starts to get more directly proportional to the I term. And of course 7.7 billion of us eating and shitting does have quite an impact. But for me it’s not fundamentally why our impact is now so devastating on earth systems and ultimately ourselves, and I don’t think Ehrlich articulated the equation as a neutral descriptor of humans as eating and shitting organisms.

    The way you write out the equation towards the end of your comment gets closer to the issue (but note that it’s different from the actual equation, and closer to the way I framed it in my earlier post in discussion with Steve L as something like I = ∑pi), but still doesn’t quite capture it for me. You write that “The levers you suggest we pull —which I agree with—are human constructs completely contained within the several subsets down from the ecosphere” and here we get to the main issue. Our growth economy is a human construct which is ultimately incompatible with the wider physical world we inhabit. Only when we confront and disassemble that construct directly rather than fiddling around its edges are we likely to avoid the negative paybacks that it imposes on the world and ourselves. Reducing human fertility, beneficial though it usually is, doesn’t confront it directly.

    @Joe. I don’t think there’s an awful lot of distance between us. I = A, or at least I = f(A) works better for me as a ‘clarifying tool’. Again, I’ll say more on this in my next post but for me the capitalist economy is key in promoting urbanization and preventing small-scale agrarian societies oriented to their local ecological bases – I don’t think capitalist de-urbanization or non-capitalist mass urbanism are very likely.

    • Well Chris, I think that clarifies our differences for me.

      I think it is that you have expertise in math, and so you expect the formula to actually calculate something properly.

      Whereas I am no expert at all in math, so I treat it as a map, not the terrain.

      I distinctly remember in Grade 10 (or maybe 9) Science Class when we were taught that atoms have a nucleus and electrons in shells around it.

      The teacher said, “This isn’t actually how it is, but it is useful for learning.”

      So I see that I think of I=PC as a thinking tool about ecology and systems, not as a calculator of material flows.

      And when the formula is used for something like Ecological Footprinting, I see it as a placeholder. P stands for PopulationS plural, perhaps thousands of distinct groups. Technology and Affluence may be inserted or removed if they are needed to answer the question being asked.

      This is why you could halve population without halving impact—it depends which of the thousands of population groups you remove. If we could remove the Rich White Western population subgroup, impact would be more than halved, despite only removing a small fraction of global population.

      So yes, I agree, if global averages are used, this formula does not calculate much very useful.

      I do wonder though, if you have been thinking in systems for so long that you can’t imagine that people do not understand basic ecology. I find ecology to be absent in most discussions in the modern world—even the basics, like two mice eat twice as much as one mouse, and eventually there will be more mice than the field can support and there will be a population crash.

      Anyway, thanks for continuing to try to clarify, I think I see the differences better.

  9. World population hangs on energy use , the industrial revolution with its sudden replacement of animals and human muscle with steam drove population growth , a man and a team could plough an acre a day , steam ploughing engines could do fifty ,( look at image 14 ,15 16. 10 furrow ploughs versus one with a horse ) food production exploded and prices collapsed , starvation no longer controled population , look at figure six here
    cheap energy has driven the population growth , from 80% of the population farming in 1750 to less than 2% now , take cheap and plentifull energy out of US farming and IMHO 75% of US land would become unproductive , hell parts of montana that now grows wheat does not grow enough per acre to feed the horse that would try to plough it , diesel replaced muscle , muscle replacing diesel will be a disaster of biblical proportions .
    world population numbers will become moot .

    • ” …cheap energy has driven the population growth , from 80% of the population farming in 1750 to less than 2% now , take cheap and plentifull energy out of US farming and IMHO 75% of US land would become unproductive…”

      Whoa horsey… there are facts, and then there are interpretations. First off, my preference for the energy – population dynamic is to observe that cheap energy has allowed population increase. Causing population growth suggests we have no say in the matter.

      Next – the reduction in ‘on farm’ population began long before the advent of ‘cheap energy’. Technology played (continues to play) a large role (and while cheap energy is itself a manifestation of technological advance, I think we’re intelligent enough to make some approximations of the difference).

      But the biggest slip in that comment for me is the assertion that 75% of US land would become unproductive by the loss of cheap and plentiful energy.

      To be fair, there is a fairly large chunk of the US landmass that is not particularly productive right now… though I suspect this is not what Diogenese had in mind. If we consider US farmland as the starting point, then a diminution in cheap energy will likely move some of the current marginal lands out of the equation. And there likely is a fine economic model that can predict how much land becomes uneconomical as energy costs escalate. But here a better word choice is ‘uneconomical’, not ‘unproductive’. The productivity is not changed by energy cost. This is not a mere semantic distinction.

      Next, let us consider energy as provided by technology. Fossil energy as coal or oil is one issue. Muscle power as derived from plant production is different. [A very significant driver of the reduction in farm population is the enormous increase in plant productivity due to technology. Agronomy and plant breeding have increased the amount of food potentially produced per acre.]
      Other non-fossil forms of energy exist (hydro, wind, solar, and in a pinch one could even offer nuclear). Technologies continue to improve the efficiencies of these energy sources. Algae have long been sitting on the sidelines in the energy debate, and perhaps their time is on the horizon.

      Suffering the loss of 75% of US farmland due to a decrease in cheap and plentiful energy is a poor prognostication.

      • I agree that the loss of “cheap and plentiful” energy might not make 75% of farmland “unproductive.”

        But the devil’s in the details. Take all non-renewable energy away suddenly, and I agree that 75% of the land would be unproductive.

        Land that has been chemically farmed for decades, using soil-destroying machinery, will go right out of production if fossil energy were to “go away.”

        Can’t imagine fossil energy “going away?” Just look at the events of the past couple days. Yea, people are still driving cars, tractors are still running, and fertilizer is still being produced. But bankruptcies are happening, and those who have any sort of cushion are cutting back production.

        Most people think the end of fossil energy will be because it becomes too expensive. But there are a few bright people out there who imagine it might go away because it is too cheap to produce.

        • Perhaps we have a different definition of “unproductive”.

          If I use the Midwest US grain belt as an example, and more specifically the roughly 175 million acres of corn and soybean production within that belt, then a 75% “loss” amounts to a bit over 131 million acres. I would go further to assert that well over 95% of the original 175 million acres have been farmed as:

          Land that has been chemically farmed for decades, using soil-destroying machinery, will go right out of production if fossil energy were to “go away.”

          Now… if your point is that the land becomes ‘unproductive’ because no one will attempt to work this land without tractors or chemicals, you either haven’t worked with hungry people, or you’ve listened to and believed someone else who has never tried to work this land. It can be extremely productive… even after all these decades.

          No-till and reduced tillage management systems proliferate throughout this geography… so there is less and less “soil destroying machinery” in use all the time. Weed control is perhaps the biggest difficulty looming in a future with reduced access to fossil fuels. But I’ve still not a met a weed that is resistant to a well handled hoe.

          If the future landscape supports no chemical fertilizer or fossil fuel then the limitations to productivity will come from limitations in human capital, ingenuity, blood, sweat, and tears. The prairie soils we currently work will still be VERY productive.

          • if your point is that the land becomes ‘unproductive’ because no one will attempt to work this land without tractors or chemicals, you either haven’t worked with hungry people, or you’ve listened to and believed someone else who has never tried to work this land.

            You’re right; I haven’t worked with “hungry people.”

            But I have worked with a lot of people whose only exposure to soil was wiping it off their feet between their car and their home. I am not convinced that many people who think food comes from Starbucks will be able to feed themselves in short order.

            No-till and reduced tillage management systems proliferate throughout this geography

            Not really!

            Those terms have been co-opted by Big Ag.

            If using “no-till” and “175 million acres” in the same context, you’re talking about Monsanto’s version of “no till.” It still involves almost as many machine passes, but one of them is spraying glyphosate instead of ploughing.

            There’s not going to be organic no-till of 175 million acres without about 175 million farmers!

            I have no doubt that prairie soils can be rehabilitated. But the “human capital” you cite as necessary just ain’t there. And ordinary people who were promised careers in industrial jobs will resist returning to the land vigorously.

          • We’re making some progress…

            On the matter of the Starbucks set not being capable of grubbing a carrot from the earth… that particular problem solves itself. They starve and remove their caloric requirements from the equation. A Darwinian solution.

            Next up – your assertion:

            If using “no-till” and “175 million acres” in the same context, you’re talking about Monsanto’s version of “no till.” It still involves almost as many machine passes, but one of them is spraying glyphosate instead of ploughing.

            First – I’m not implying this sort of context, though I will stipulate I’m probably outnumbered among agrarians who would wonder why this is even an issue. And even though I’m not a ‘glyphosate guy’ I will offer that comparing a pass of a plow to a pass of a chemical sprayer is not remotely comparable for either fuel consumption, soil compaction, habitat destruction, or soil degradation (this last mostly a function of the previous two). There really is room for deploying ‘no-till’ and ‘reduced-till’ in a world outside Bayer (current owner of Monsanto).

            As for your last point about needing 175 million farmers for 175 million acres… I disagree on the merits… but regardless of the disagreement I have to wonder why it might be a problem in the first place.

            To the merits… as a boy our family (a force of 2 adults and four children) cared for 10 acres of garden, another dozen acres of field crops, all on a half FTE from one of the adults and roughly 3 FTEs from the youngsters – ages 6 to 13. So a mere acre per farmer is an insult to an ambitious (hungry) person. I will offer that a tractor was used to seed 4 of the 10 garden acres… and the tractor also employed in the field crops. But still…

            Lots of folks today find themselves employed well outside their past dreams and aspirations. Likewise, lots of folks today find themselves vastly overweight and suffering from non-communicable diseases that largely result from sedentary lives and eating crap. Put the phone down, get off the couch, roll up your sleeves and grub some carrots from the earth. If an acre is all you get, you’ll be fine. The earth is still productive.

          • as a boy our family… cared for 10 acres of garden, another dozen acres of field crops… So a mere acre per farmer is an insult… I will offer that a tractor was used [emphasis mine]…

            I think we’re in heated agreement here, mostly.

            I made my first farming profit at age 13. Me and two younger siblings managed five acres of sweet corn. Dad fronted us the cost of fuel, seed, and fertilizer. I did the machine work, we all did weeding, suckering, harvest, and sales. After paying Dad back, we split about $300 profit — that was a heck of a lot of money in 1967!

            But could we have done it without a tractor? No way. Absolutely no way. We needed those fifty horses from the Farmall H. Fifty horses! That traction power would have required at least 50 acres for pasture and hay!

            Yea, yea… a team of four would have made things much easier over all human labour. So double the five acres we had in corn for our “tractor fuel.”

            The point is that human labour is pretty wimpy, compared to what we’ve become used to.

            I’ve recently had to do formal assessment of agricultural labour needs. You guys were exceptional! The average labour needs for North American truck crops, using low mechanization, high labour organic/Permaculture techniques is about one acre per worker.†

            You can’t expect soft city workers to work as hard clever as you did. You can’t even expect them to work as hard as the seasoned farmers in the Hendrickson study.

            Today, there are about 700 city folk for every one working the ground. With an agricultural background, it is easy for you and I to think they can just get plopped on a bit of prairie and manage to feed themselves. But it’s not going to be that easy.

            Grower to grower: Creating a livelihood on a fresh market vegetable farm
            John Hendrickson, CIAS Outreach Specialist
            University of Wisconsin-Madison College of Agricultural and Life Sciences
            October, 2005

          • theymay be after a longish time but a hell of a lot of land today is basicly hydraponics , it used to be ” dry land farmed ” but most dry land farmers went bust during the 1960’s ( my family did ) unable to compete with irrigated heavily fertilised soil and DDT plus government quotas on legumes like peanuts that added nitrogen , lots of land around here was burned out by cotton it now grows misquite , juniper and little else , one cow / calf unit to twenty acres . thats the USDA recomended stocking rate !

  10. Glad some peace has broken out 🙂

    Interesting point about wheat in Montana. It’s tempting to advocate homesteading rather than broadscale wheat farming, but if Jonathan Raban’s book ‘Bad Land’ is anything to go by, maybe that won’t turn out too well…

    Muscle replacing diesel as a disaster of biblical proportions? Possibly. But I think the more our culture resists that possibility, the more that’s likely to become a self-fulfilling prophecy.

  11. Seems to me an angle that hasn’t been explored explicitly yet in the conversation is whether Population could be a dependent variable. The hypothesis would be that population growth has been enabled by advances in technology and increases in fossil energy extraction. The equation would look something like this:

    Population [people] = Fossil energy extraction [Joules fossil energy] x Energy services delivered per unit of fossil energy [Joules services / Joule fossil energy] / Energy consumption per capita [Joules services / person]

    Well, reading the comments again, I think this is what Joe and Steve were saying.

    This framing is more in line with ecological theories where populations tend to grow until their environment can’t support them anymore. The framing leads to some interesting corrolaries:
    – Any increase in fossil energy extraction leads to an increase in population.
    – However, any improvement in efficiency would also lead to an increase in population.
    – And, any reduction in energy consumption per capita would also lead to an increase in population.

    The implied “solutions” (if reducing population is your goal) would be to:
    – decrease the amount of fossil fuel extraction
    – decrease the efficiency with which fossil fuels are turned into services
    – and/or, increase per capita consumption

    I’m not saying this is the right framing. The conclusions start to get a bit non-sensical. I tend to agree with Chris in his scepticism of seemingly simple formulae. They just don’t capture the feedback loops between the different variables. If I’m going to be mathematical about it, I would prefer a systems diagram, showing the various relationships between the different variables.

    At that point, the rates of change for each variable in the system, as well as the speed at which various feedback loops kick in become key.

  12. Very interesting comments from Joshua, and Clem above.

    On the issue of P as a dependent variable, in musing on my response to Ruben I played with this idea and tried the equation P = IAT out for size. But I think Joshua calls it right – the parameters and feedback loops confoud simple formulae, so systems diagrams may be better (though I can’t say I’m a big fan of these myself either!) I think we can all agree that I = PAT draws attention to some relevant issues. The question is whether it does so in a way that’s illuminating or misleading.

    The way Joshua teases out the logic of P as a function of energy is thought-provoking. But, thinking about the earlier discussion with Joe and Steve, I’m cautious about any teleological reasoning along the lines that if there’s a potential new energy source then humans (or other organisms) will inevitably arise/organise to exploit it – especially if that energy source requires some kind of social organisation or development in order to identify and exploit it. Another approach in the ecological literature – suggested by Victor Court who we were discussing here a while back – is the tendency of mature ecosystems towards tight cycling and conservation of energy, and structural complexity, rather than the familiar language of overshoot and collapse. Though the move towards tight cycling and complexity probably looks like overshoot and collapse from the perspective of many of the organisms undergoing the transition.

    To Clem’s comments, I’ll just largely tip my hat – while still being sceptical that energy efficiency or new energy technologies will extricate us from our present difficulties. Certainly, when we talk about energy availability it’s useful to think in terms of more immediate plant energy as well as more intermediate fossil energy. More on that soon, I hope.

    • I’ll just note that the I=PAT formula is from 1970, a time when people in industrial countries were becoming very concerned about the environmental impacts of industrial pollution. A lot of people at that time thought that we could mitigate environmental impact just by changing industrial technology to “clean” processes and carry on into a glorious high tech future (ecomodernism is just a continuation of that mindset).

      The I=PAT formula was used to convey the message that there is no way to eliminate impact completely as long as population or affluence are growing, simply because industrialism itself, no matter how carefully designed, is an assault on the stability and integrity of the biological world. I still believe that message.

      • “Industrialism itself, no matter how carefully designed, is an assault on the stability and integrity of the biological world.”

        This ties in with something Joe wrote earlier:
        “We could get rid of capitalism entirely and we would still have an impact problem…”

        A facile counterexample to the inherent environmental evils of capitalism would be the USSR, whose industries were big polluters. Perhaps “industrialism” is the biggest bogeyman?

        I also blame the quest for building and maintaining empires (political and/or commercial), regardless of whether the governance is by dictatorship, democracy, theocracy, or communism.

        Regarding the lack of caring for the environment, and policies which favor short-term gains over the long-term health of ecosystems, I imagine that ‘unenlightened’ or corrupt leadership can exist in any system of government.

        • Perhaps “industrialism” is the biggest bogeyman?


          Are you familiar with Ivan Illich?

          If not, go grab a book of his, right now! He has explored this path in exquisite detail. My favourite — a short, quick read — is Tools for Conviviality.

          When we speak of “industry,” we usually think of smoke stacks and artifacts, or maybe something as abstract as software. But Illich takes that concept down to industrial education, industrial medicine, industrial culture — citing all such things as destroyers of “conviviality,” or the art of living together.

          • Thanks for the link. I’ve read some excerpts of Illich’s works, but haven’t seen that book.

        • The problem with invoking the USSR as a counter-example to capitalism is that its version of communism was wholly imbued with a commitment to capital increase – and communism in general is a ‘mirror of production’, another version of technocratic, accumulative rupture. Generally, once a capitalist ‘world system’ is in place, it’s difficult for any other political economy to coexist with it without replicating its form, despite apparent differences – kind of like a virus coopting a cell.

          It’s true, though, that it would be hard to deliver consistent capital increase in the modern world without mass industrialism. As I see it, we’re stuck in a vicious, reinforcing circle of modernist culture, capitalist economy and industrial society. But the logic of capital increase is what gives the system its shape and motion. Without it, mass industrialism, mass urbanism and other aspects of our impactful lives would falter.

          • …kind of like a virus coopting a cell.

            Timely, succinct, and vivid. Nicely done.

            I started to describe a quibble with this simile and then quit when I realized it is even more powerful than I first imagined. Viruses don’t kill ALL hosts. Indeed one can offer the argument that viruses can have a silver lining – strengthening the herd.

            And viruses mutate. So if capitalism is analogous to a virus, then we have two paths forward. We either evolve to tolerate
            (or resist) the virus… or we watch carefully for a mutant strain that can coexist with capitalism and not cause large scale environmental destruction. This latter viral mutant (capitalism lite, if you will) could (should) coexist with conviviality among our fellow man and our fellow species who we share this planet with.. then over time the mutant replaces (or minimizes) the former type.

            The Small Farm Future virus. Vaccinations optional.

        • A recent article at considers that the USSR was actually “state-capitalism”.

          “Nowhere in the Soviet Union, People’s Republic of China, Vietnam, Cuba, etc, do you see an entire economy made up of independent worker-owners who own and control their own enterprises. Rather you see state control of enterprises using anti-democratic methods to deny human beings their fundamental rights, just as private owners do in the rest of the world.”

          The article also clarifies that markets do not require capitalism.

          “Capitalism is not markets. Markets existed before capitalism and will exist after capitalism. Markets can be an efficient means of distribution, but little more. Instead, capitalism is a mode of production. A mode of production can be defined by answering simple questions: who owns and controls — who makes the decisions on what to produce, how to produce and what is done with the proceeds — and who inputs the labor.”

          Worker Self-Directed Enterprises: The Cure for Capitalism
          By Kevin Gustafson

          • Yep, I agree. I devote quite a bit of attention in my forthcoming book to discussing this point, that ‘markets’ are not fundamentally a feature of capitalism, and that capitalism is fundamentally a project of the state.

  13. Incidentally, someone mentioned to me the issue that increased life expectancy as well as over-replacement fertility is also driving population increase. Fertility seems the better focus for policy intervention, on the grounds that it’s preferable not to produce people in the first place than to wish them an early death. But life expectancy isn’t much talked about as a driver of population – I’d be interested if anyone could point me to any quantitative analyses along these lines.

    Meanwhile, thanks to Jan and Clem for their interesting debate. My brief interpolation would be:
    – yes, a lot of ‘unproductive’ land can be made productive by different and more labour-intensive methods
    – no, most countries aren’t remotely skilling themselves adequately for such a transition
    – yes, ‘chemical no-till’ is more energy and soil efficient than tillage farming
    – not sure that it’s less habitat destructive though
    – yes, fossil-fuelled traction gives modern farming a massive energetic boost, and is necessary in the present economy if you’d care to make a tidy profit from 5 acres of corn (though I’m guessing that ‘tidy profit’ and ‘5 acres of corn’ make stranger bedfellows now than in the 1960s)
    – no, you don’t necessarily need a massive fossil-fuelled boost to produce your own food from the land (though how best to do so is an endlessly thought-provoking puzzle)

    • – not sure that it’s less habitat destructive though

      Think soil biota. Not all habitat is about megafauna… and properly employed herbicides can facilitate cover cropping while harming fewer microbes than a plow.

      • I WAS thinking soil biota. I take your point … though I’m not convinced that wide application of stuff like glyphosate (anti-biotic, chelating, possibly carcinogenic and often not employed all that properly) will prove more beneficial long-term. But maybe I could be persuaded otherwise…

        • “stuff like glyphosate”… oh well, too little time to get ‘into the weeds’ on this one.

          As for “often not employed all that properly” … I agree in principle – misuse occurs. But like your capitalism as virus simile – there is selection against abusers. Time horizons and selection pressures may not suit our own, but if we do succeed in moving toward a small farm future there should be more eyes per acre and less need for such broad acre solutions as “stuff like glyphosate”.

          If one could interview a night crawler and inquire which she preferred a farmer employ… a plow or a herbicide (and we imbue her with the ability to understand the question) I’m guessing she’d prefer the latter.

          • Clem, you’ve switched phyla on me – we were previously talking about bacteria! But yes, I’d agree a night crawler would probably opt for the herbicide over the plough. Whether her (knowing) descendants would make the same choice with hindsight seems to me more debatable.

            Or one could take the more literary route and invoke John Stewart Collis – “the worm forgives the plough”…

          • If one could interview a night crawler and inquire which she preferred a farmer employ… a plow or a herbicide (and we imbue her with the ability to understand the question) I’m guessing she’d prefer the latter.

            Boy, you are persistent in your defence of chemical farming!

            Glyphosate has an impact that cascades through ecosystems. Areas that have been under intense chemical agriculture for a long time have as little as one-quarter the organic material content — which your little night crawler lives from!

            Kill it before it grows, and you starve the detritivores. Corn stover just doesn’t have the nutrition of young weeds.

            I once drove across Washington State in the winter, and being an avid bird watcher, I noticed that for large areas, the buteos were missing.

            Ordinarily, I’d expect to see a Red Tailed Hawk about every mile, still-hunting from a utility pole. But there were none at all for many tens of miles.

            When you’d enter small town, you’d see them again. I looked closer, and noticed that where the buteos were absent, there was not a speck of green. I asked a Central Washington farmer friend what had happened.

            “Oh, that’s ‘fall burn-down.’ We go over everything with a pass of RoundUp™ in the fall, and then the weeds aren’t there in the spring.”

            And neither are those meadow voles, deer mice, lagomorphs, serpents, and other things that used to survive off what the plough and cultivator failed to remove. And nether are those further up the food chain that used to live from those little green-eating things.

            Kick the legs out from under a table, and you can’t expect the table top to remain suspended in the air. We are taking part in a huge experiment — how much habitat can we eliminate, and still be able to survive?

            Sterilizing the soil is not agriculture — it’s warfare against all life.

          • Boy, you are persistent in your defence of chemical farming!

            Glyphosate has an impact that cascades through ecosystems. Areas that have been under intense chemical agriculture for a long time have as little as one-quarter the organic material content — which your little night crawler lives from!

            Come on Jan… your selective reading of my comments gets tiring. You constantly attack glyphosate when it is not the particular chemical I’m concerned with. I’ll grant there can be issues with glyphosate when it is abused. But there are also issues when someone picks up a single datum point and extrapolates it against an enormous population.

            First it is the notion that 75% of US farmland will magically become “unproductive” just because someone can’t find folks to work like he does. There is no connection to the land’s productivity… it’s a human failing.

            Next is the notion that intensive chemical farming has reduced SOM to a quarter of its original prairie value. I agree there is less SOM in cultivated fields now than before farmers started working fields, but more of the SOM loss is down to actually plowing than to herbicide use.

            Yes, earth worms live off of SOM, fungi (another phyla for you Chris) and bacteria… which in turn DO decompose corn stalks (and soybean pods, nodules, stems…). Even though I did caution above that I’m not a ‘glyphosate guy’ I’m enough of an agronomist to say for certain that glyphosate is NOT a soil sterilant. Insinuating that it is just raises a question of how persistent you are in looking to blame something for conditions you don’t like.

            Thanks for the story about your trip across rural Washington. There are parallels there to some things we see here in Central Ohio that do deserve our attention. There are far fewer insects around these days, and thus fewer birds that used to feed on them. The European Corn Borer (ECB) has been pushed to extremely low levels. Glyphosate has nothing to do with this loss – but deployment of GMO corn with the Bt trait that kills ECB has very much to do with it. So this is me NOT defending chemical agriculture.
            One should scratch the noggin though and ponder why there used to be SO many ECB that an evening drive through farm country would literally cover the windshield with dead bugs. Corn was (still is) grown everywhere in these parts. Today a similar drive can occur with almost no bugs on the windshield. Perhaps a good thing for the couch potato type, but not for the birds (though on the side of the Bt germplasm – because it has replaced some very poisonous chemical insecticides some will consider that a benefit).

            There are more worms under No-till conditions. Not all herbicides are evil chemicals that will burn the earth into oblivion. Not all farming systems are going to satisfy everyone.

            [and your Red Tailed Hawk on a power pole… likely waiting for a passing car to kill something. Their hunting skills are eroding. So naturally we want to abandon power poles and roadways. They screw up the planet]

    • I almost wrote about that in my previous comment.

      I once did some speculative modelling of what would happen if birth rates dropped to zero (in a simple excel spreadsheet). How quickly would population reduce? Basically, because so many people today are young and relatively healthy, it would take a long time for them to die. Population would only decrease relatively slowly.

      According to this webpage, around 25% of the world’s population is under 15. It will take 60 years for those people to be 60-75 years old and to start dying in appreciable numbers (absent any of the four horsemen that we’re precisely trying to avoid with this exercise). That’s 2080.

      So, based on those simple (and probably flawed) assumptions, with 0 children being born for the next 60 years, we would achieve a population reduction of 75% by 2080. In simple terms, turn the population pyramid on its side and you have the population decline for the next 10 decades mapped out, assuming 0 births.

      If population is truly a “problem”, rational responses need to look at both ends of the human lifespan. Life expectancy needs to be critically assessed too. Fertility reduction cannot “bend the curve” anywhere near fast enough and a focus on it, especially if it squeezes out other ways of reducing impact, is more political than rational.

      I could crunch the numbers properly again, but I hope my general argument is clear. I think I had a longer comment on making a similar point a couple of years ago.

      • A re-statement of the above. 82% of the world population is younger than 54 and doesn’t expect to die in the next 10 years. Implementing a zero-births policy would only achieve an 18% reduction in population by 2030. This drastic measure (to the point of being totally unrealistic) is nowhere near enough to avoid 1.5 or even 2 degrees of warming.

        • My comment on, from 2 years ago:

          “overpopulation is one of the root causes of the human-nature-climate problem. But believing that birth control could solve the problem in any meaningful way is foolish.

          Firstly, even if everyone stopped having babies, starting today, we would still be stuck with the existing population for quite a while. Current crude death rates are about 8 per 1000 per year (quick google search). Using that decline rate, we’d reach 5.7 billion by 2045. Humanity would still be well into overshoot territory.

          My point is that human populations (plural) will have to fall to carrying capacity through increased mortality rates, with decreased birth rates making little difference.

          Our work should be to work as hard as we can to increase local “carrying capacities” while trying to remain humane in a world characterised by high death rates (famine, war, illness are the main options). We need to developing a system of ethics that can deal with the moral dilemmas of overshoot. Not easy.”

          And another comment, also from 2 years ago:
          “I think the point I was trying to make is that while having less people on Earth will almost certainly make our global situation more eco-logically sustainable, there are fairness issues at stake.

          There are many possible scenarios for population reduction. Each of which involves a loss (of life) for the people involved and more or less gain for everybody else. One of the most popular approaches is to prevent new people being born – the only immediate losers are unfertilised sperm and eggs, hardly people at all. But this puts the burden on the people who want to have children who must forgo that for the benefit of everyone else on the planet. These live predominantly in less wealthy countries.

          One of the much less talked about approaches is to change social norms around dying and the end of life. The reasons for this lack of popularity are obvious: the losers are real people, alive today, often enjoying retirement and relative wealth, predominantly in developed countries, who are (understandably) very concerned for their own welfare and usually want to live as long as possible to see their grandchildren and great-grandchildren grow up. The winners would be the young and the not-yet-born, hardly a very vocal or powerful group on the world stage.

          I hope I’ve clarified my position a bit. Yes, fundamentally over-population is a root cause of global ecological depletion but that doesn’t help to define a “solution”.”

          • Thanks Joshua – interesting observations.

            Since 1960 global population has increased from about 3 billion to over 7.5 billion today, while global average life expectancy at birth has increased from 52.6 years to 72.4 years over that period. I’d be interested to know how much the latter change has driven the former.

          • Using that data from Chris to (ballpark) estimate the influence that increased life expectancy has on the total population number, I came up with 237 million extra people in the world today due to the increased life expectancy since 1960.

            I used a simple spreadsheet that assumed linear increases in population and life expectancy between 1960 and 2020.

            With the increasing life expectancy, and the simplification that everyone born in a given year has the same life expectancy for that year (52.6 for all those born in 1960, for example, and higher in each successive year), the result was that everyone born in 1965 and earlier would be dead by 2020.

            With the life expectancy not increasing, staying at the same 52.6 for the entire period 1960-2020, the result was that everyone born in 1967 and earlier would be dead by 2020.

            The difference in these two scenarios, namely the effect that the increase in life expectancy had on today’s world population, is equal to the number of births during the years 1966 plus 1967, which is 188M + 119M = 237M.


          • Correction
            The difference in these two scenarios, namely the effect that the increase in life expectancy had on today’s world population, is equal to the number of births during the years 1965 plus 1966, which is 117M + 118M = 235 million people.

          • Correction to the “correction”
            The difference in these two scenarios, namely the effect that the increase in life expectancy had on today’s world population, is equal to the number of births during the years 1966 plus 1967, which is 118M + 119M = 237 million people.

          • Lost in the averages, and therefore not included in my result, is the potential for increased births of successive generations due to improvements in the child mortality rate (which can be a component of the increase in life expectancy numbers). A lower child mortality rate can effectively bring more children into adulthood where they can have their own children (and grandchildren…), and I didn’t account for that.

          • Thanks for that Steve. I’m not sure I’ve totally grasped your methodology, but you inspired me to do a spreadsheet of my own. Instead of life expectancy, I looked at birth rates (31.8 per 1000 population globally in 1960, 18.7 per 1000 in 2017) and death rates (17.7 in 1960, 7.5 in 2017) year on year 1960-2017. I assumed that Population in year x = Population in year x-1 plus births in year x-1 minus deaths in year x-1. This seems to be roughly borne out in the actual figures when I calculated them from the rates.

            If you then keep the births year on year the same as the actual figures, but calculate deaths by keeping the 1960 figure of 17.7 per 1000 constant across all years you get a 2017 population of 5.1 billion, compared to the actual 2017 population of 7.5 billion. The population in 1960 was 3 billion, so this method crudely implies that population increase since then splits roughly 50/50 between high birth rates and low death rates – which is very different from your finding. But maybe I’ve made a terrible mistake?

          • Chris, your approach seems more legit, looking at annual births and deaths. Without recreating your calculations, I suspect the difference in our results is largely because I didn’t include the effects of the child mortality rate improvements, along with other simplifications.

            In 1960, the global child mortality was 18.5% dying in the first 5 years. By 2017, this had improved to 3.91%. That’s a lot of surviving children (having their own children) that I didn’t account for.

          • “The 20th century world population ‘explosion,’ from 1.6 billion in 1900 to 6.1 in 2000, was a direct result of the rapid decline in mortality rates in less developed countries. As death rates declined, life expectancy rose, leading to higher population.”

            Population Reference Bureau

      • the vast majority of US farmers are over 65 , their combine d knowledge dies with them , they can only keep on going because of air conditoned tractors , like me too cotton pickin old to walk behind a plough , a hard days work in 90 degree temps with 80% humidity would kill most of us ! ourclimate is not as kind as the UK .
        no til has been tried the machenery is very expensive and the tractors needed are enormous ( here they have to be tracked to gain traction to pull the sed drils soil compaction becomes a problem too )
        As for cities /population only one city in the USA has gravity water supply , thats New York all the rest are pumped , an electrical falure would empty most cities and towns , here the water table is 100 foot down there are a few hand dug wells Railway mostly , in Lubock its 1000 foot deep , beyond the reach of wind power .

        • According to the link below (2018) the average age of an American farmer is 58. For the “vast majority” to be over 65 would require some fairly young members in the cohort. The average beginning farmer is 47. The occupation does trend toward the longer toothed… but the reality isn’t quite so dire as presented above.

          Other fascinating statistics there as well. USDA defines a “small” farm as one grossing less than $350,000 per year. I very easily qualify by that standard. And 56% of net farm income in the US is earned on “large farms” – those with gross income > $1 million. There’s some organic data there as well. Have a peek.

          My 64 year old Allis Chalmers D-17 will pull a four row (perhaps even an 8 row) no-till planter… at least on the prairie soils in these parts. It has air-conditioning of a sort… as there is no cab, if there is a breeze, there is air-conditioning. As the AC and I are just about the same age… we’re both older than the average US farmer. Oh well.

          City water is another matter. I won’t argue on that front.

          • in the sandy land round here my old ford 2000 (1960 ) bogs with a two furrow plough , single furow is all it can pull , four wheel drive with double tyres all round is the norm with tracked taking over as funds allow .
            one thing the farmers around here are not fit , most have had back , shoulder surgery and some have had hip replacement surgery , without machinery they could not farm , just generaly worn out , there kids are in Austin , Huston ,Dallas Fortworth in nice comparitivly easy jobs compared to farming . few stay to face the vaguries of farming , they like the regular paycheck and fourty hour work weeks .

          • there kids are in Austin, Huston, Dallas, Fort Worth in nice comparatively easy jobs compared to farming. Few stay to face the vagaries of farming; they like the regular paycheque and forty hour work weeks.

            CoViD-19 is taking 40 hours and a paycheque away from many right now!

            That might change some people’s minds. We just put in extra collards and cabbage, and have our potatoes in, with hundreds of tomato and pepper starts going, and three dozen eggs and two gallons of milk a day.

            Compared to those who deal with 50 or more people a day, who have been laid off, I’m not missing a regular paycheque at all.

  14. Just wanted to thank everyone for some especially illuminating threads and comments under this post. My patchy responses are more a reflection of the state of my to do list than anything else…

  15. “The 20th century world population ‘explosion,’ from 1.6 billion in 1900 to 6.1 in 2000, was a direct result of the rapid decline in mortality rates in less developed countries. As death rates declined, life expectancy rose, leading to higher population.” — Population Reference Bureau

    With nary a mention of Mister Haber and Mister Bosch. Hmmm.

    • Hmmm, to be a tad polite one could refer to them as Dr Haber and Dr Bosch. Just as a rapid decline in mortality rates is also due to the efforts of untold numbers of Drs. And why stop here? We should add the efforts of Dr Norman Borlaug, Professor Fleming, and a list to fill several pages.

      There are billions and billions of us… likely to be a further few billion more before our numbers crest. Pointing fingers won’t change the reality. Let us get on with making our way and preserving something for those who will follow.

    • Then of course there’s Dr Smaje and his radical schemes for social improvement…

      But yes I agree that it’s more than a one card trick. And I’d also observe that the legacy of all of the doctors you mention is somewhat ambiguous…

  16. I find the death rate/life expectancy point interesting inasmuch as it’s so little discussed publicly as a force driving population increase. Doubtless reducing fertility is still the best option for pushing population decline (though not IMO the best option for reducing human environmental impact), but attention to mortality does subtly shift the focus from the childbirth phase of life. Interesting that Covid-19 seems to be so differentially felling people from older age groups…

    Looking at global birth and death rates, the former spiked sharply upwards and the latter sharply downwards in the 1960s. Since then, they’ve both declined slowly at about the same rate – so where we are today seems like a legacy of the 1960s. I daresay Haber-Bosch has something to do with the postwar birth/death trends, though I’m not sure how directly causal it was. Ultimately, the main alternative to ammonia in factories is houses in the country and hands in fields, which takes us back to the issue of skills and mentalities.

  17. Perhaps I’m not paying sufficient attention, but I’ve just seen a headline from a month or so back suggesting many in the UK government don’t think the country needs farmers (small or otherwise). Take Singapore for example they appear to be saying.

    Indeed. What could possibly go wrong?

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