Last week, Small Farm Future chalked up yet another first – the first vehement critique of one of our posts by a working academic with apparent expertise in the matter at hand. The post was this one about global population and its entailments that I published in June, and the critique came from Dr Jane O’Sullivan of the University of Queensland in Australia (our exchange is linked below).

I’d precis the main substance of Dr O’Sullivan’s critique as follows: my post failed to consider the importance of top-down government or expert-led population control policies (broadly conceived) in reducing global fertility (ie. births per woman) over the last 50 years, and failed to consider the implications of the recent slowdown in the decline of the fertility rate and its causes. If that was all that Dr O’Sullivan had said, it would have been easy for me to concede these points (especially if she’d made them politely). I don’t think the concession greatly alters the main points I was making in that post, though perhaps it does a little. But in the course of our ill-tempered exchange (I’m sure the fault was partly mine…though not, I think, entirely) Dr O’Sullivan also unleashed quite a barrage of assertions that in my opinion varied from the somewhat questionable to the downright misleading, along I’ll admit with the occasional useful nugget. I should probably give myself more time to reflect on the issues, but some of them are highly relevant to the wider themes of this blog, and I think are less clear-cut than Dr O’Sullivan supposes. So I thought I’d write a quick, work-in-progress kind of response now to present the issues as I see them, in the hope that other commenters may bring some wider illumination.

Here, then, are just a handful of the many issues arising out of the exchange, each one wrapped up with a point for discussion. The exchange itself can be found lurking at the bottom of my offending post, but is also linked at the end of this one for convenience.

The relationship between human fertility and poverty.

Dr O’Sullivan wrote that “population growth is the main driver of impoverishment and local environmental damage in high-fertility countries”. Focusing for now just on the impoverishment side of things, I think this claim is empirically wrong and could well be politically disastrous.

Let’s take for illustration the ten countries with the highest fertility rates in the world, all but one of which are African (in fact, all but nine of the fifty highest-fertility countries are African). According to the World Bank’s World Development Indicators the top ten are Niger (with a current average fertility rate of 7.2 births per woman), Somalia (6.3), Democratic Republic of Congo (6.1), Mali (6.1), Chad (5.9), Burundi (5.7), Angola (5.7), Uganda (5.6), Nigeria (5.5) and Timor-Leste (5.5).

An elementary knowledge of the recent and longer-term history of these countries and their regions would surely call into question the claim that population growth is the main driver of their impoverishment. I guess I could accept Dr O’Sullivan’s claim if it was rephrased thus:

“Leaving aside the net annual outflow of billions of dollars from sub-Saharan Africa to the rest of the world (see eg. Jason Hickel The Divide), and leaving aside also the fact that large parts of it are comprised not by ‘developing countries’ but by areas largely excluded from the distribution of global surplus to the extent that they’ve become politically dominated by violent non-state or quasi-state actors (see eg. Mark Duffield Global Governance and the New Wars), then there is some evidence to suggest an association between impoverishment and population growth caused by high fertility.”

But after reading through Dr O’Sullivan’s linked paper, I’m not convinced that that evidence is quite as strong as she claims. A lot of the evidence she discusses is based on country-level data suggestive of GDP growth postdating fertility decline. There are some problems with this aggregate-level post hoc ergo propter hoc argument as a justification for reducing individual fertility as an anti-poverty strategy. If one wants to argue that high fertility is the main driver of impoverishment within these countries then it’s necessary to show that, on average, a resident individual who has x children experiences greater poverty over their total lifecourse than another individual starting at an identical socioeconomic level who has <x children. And then it’s necessary to show that this effect is more powerful than other ones, such as the financial and resource drain from these countries and the effect of their political structuring.

Dr O’Sullivan does cite a review paper1 discussing research that may be suggestive at least of the first part of this, though its conclusions are expressed more cautiously than hers. But overall I think there are some problems of causal inference in parts of her paper. A problem I have with much ‘development’ research of this kind is its reification of the country as a unit of analysis, as if the world comprises a level playing field of nation-states each at a better or worse point of possibility on some universal ‘development’ trajectory. There doesn’t seem to be much sense of the uneven geopolitics of a world economic system and the implications of that for the wealth and poverty of nations.

But what troubles me most about Dr O’Sullivan’s assertion that population growth is the main driver of impoverishment in high-fertility countries is how that statement might play out in a world where isolationist and nativist voices are rising to political prominence in the wealthier countries. So let me rephrase her assertion once again, this time as it might be interpreted through the beady gaze of the US president, perhaps the best-known of those voices:

“People who live in shithole countries are poor because they have too many babies – so why should we do anything to help them?”

I appreciate that that’s absolutely not what Dr O’Sullivan is saying, but I think it might well be what a lot of people would choose to hear – and as I tried to suggest, there are a lot of pernicious opinions abroad concerning the responsibility of the poor in general and of poor Africans in particular for their own misfortunes, which would gladly assimilate arguments from intellectually respectable sources that fertility is the main driver of poverty. Dr O’Sullivan rebuffed my attempts to discuss this with her as “ad hominem attacks”. So be it. I acknowledge that unwanted pregnancies are a major issue in high-fertility countries, while for her part Dr O’Sullivan says she never denied there were “other factors at play”, but if one links fertility to poverty with no reference to the geopolitical structuring of global poverty – especially in the present political climate – I’m not sure that caveat cuts it. The consequence of proposing that the best way to tackle poverty is through population control policies might well be a further reduction in population control policies. I don’t like to get involved in arguments with other wealthy westerners about who’s the better champion of the global poor, but I do find it a little hard to swallow the charge of irresponsible writing from someone who draws the links between high fertility and poverty so complacently.

Discussion point: population growth is not the main driver of impoverishment in high-fertility countries.

Population, environmental damage and climate change.

It’s undoubtedly true that, as Dr O’Sullivan suggested, population growth is a driver of local environmental damage wherever it occurs. Well, it’s undoubtedly usually true. But she seems curiously anxious in her writing to emphasize the environmental damage (including greenhouse gas emissions) associated with high-fertility, low-income countries and to de-emphasize the damage caused by the low-fertility, high-income countries – even to the extent of making the spurious argument that lifestyles in the latter countries haven’t got more resource or emissions intensive in recent decades.

The main point I want to make here is not so much about which countries bear most responsibility for global environmental ills. The real problem as I see it is that we only really have one model of development and prosperity – the model that the low-fertility, high-income countries have followed – and if every other country follows it, it’ll be ruinous. Actually, it’s not possible for every country to follow it for economic as well as ecological reasons. But to the extent that that’s what’s on offer, it’s still ruinous. And it does have to be said that the offer has largely been orchestrated out of Washington DC, and to a lesser extent Beijing and Brussels, in service of those jurisdictions’ interests. So while there’s much to be said for population control, I think the notion that population control is the most important precursor to economic development and environmental protection is problematic. Perhaps one issue lurking behind my debate with Dr O’Sullivan is that we have pretty different ideas about what will ultimately count as ‘sustainable development’.

But I do also want to make the point that it is the low-fertility, high-income countries that bear most responsibility for global environmental ills – most especially greenhouse gas emissions, which are important not only in their direct effects but as an index of the wider environmental bads associated with the economies that disproportionately produce them. Dr O’Sullivan writes that “apart from climate change, most of the drastically negative impacts (on deforestation, soil erosion, biodiversity loss, fertiliser run-off, plastics in the ocean, overfishing, destruction of wetlands, draining of aquifers etc) is not happening in or in the name of the most industrialised countries.” I guess I’d argue firstly that a lot of all that is happening “in the name of” industrialized countries (my point in the previous paragraph)…besides which, things like plastic, synthetic fertilizer, modern fishing fleets etc. surely are inherently ‘industrialised’. Maybe more importantly, at our present point in what Dr O’Sullivan calls “the human project” her “apart from climate change” is a pretty big exemption – somewhat akin to me saying that apart from drinking a daily bottle of whisky I’m teetotal.

The graph below shows the carbon dioxide emissions produced in Australia over the last fifty-odd years in blue and the emissions produced in aggregate by the nine African countries previously mentioned with the highest fertility in red. I think it’s quite revealing – in 2014, Australia’s 23.5 million people produced almost two-and-a-half times more carbon dioxide emissions in total between them than the 389 million people living in the nine highest fertility African countries (we’re talking total, absolute emissions here, not per capita ones). True, Australia’s emissions have dropped a little recently – possibly only by displacing them elsewhere? But I trust nobody’s going to tell me I haven’t properly attended to this decline…

Last week while Dr O’Sullivan and I were debating, the Australian deputy prime minister Michael McCormack responded to the IPCC’s latest impassioned report on the climate change emergency by saying that the Australian government would not change its policy and reduce coal production “just because somebody might suggest that some sort of report is the way we need to follow and everything that we should do”.

I’d like to suggest that if Australians voted out Mr McCormack and replaced him with a serious politician who paid attention to the IPCC it would be a far more effective form of environmental damage-limitation than pursuing policies to limit population growth in, say, Nigeria. Let me try to quantify that statement. Please forgive me if I’ve got this calculation badly wrong, but by my reckoning in 2016 Australia produced 500 million tonnes of coal, which translates roughly into a billion tonnes of CO2. It’s predicted to increase that production by 1.1% annually over the next few years. A paper cited by Dr O’Sullivan2 suggests, I think, that by the year 2100 Nigeria could reduce its emissions from 2005 levels by 35% if it pursued population policies that put it on the low variant of the UN’s fertility projections. In 2005, Nigeria’s emissions were a little over a hundred million tonnes of CO2, so if it reduced these by 35% that would mean its emissions in 2100 would be about 37 million tonnes less – which is 4% of the emissions from Australia’s current annual coal production, or an amount that would be canceled out in less than three years just by the 1.1% annual increase in production. On current measures of per capita emissions, one extra Australian adds CO2 equivalent to that of about 41 extra people from the high-fertility African countries (probably an underestimate). At those levels, the 5.5 million extra Australians predicted by the UN medium fertility population variant in 2030 over 2012 will be responsible for more emissions than the 230 million extra people predicted for the nine highest-fertility African countries.

Dr O’Sullivan argues in her paper that access to voluntary family planning and birth control in the least-developed countries in order to minimize population growth is ‘low-hanging fruit’ in terms of climate change adaptation and mitigation (though the relationship between ‘birth control’ access and fertility seems quite debatable). But what constitutes ‘low-hanging fruit’ is a matter of political choice as well as technical feasibility. Promoting people’s ability to control their fertility needs no wider justification, but it’s not clear to me from what vantage point the extension of this ability into the least developed countries constitutes lower-hanging fruit for climate change mitigation than, say, reducing Australian coal production by a few percent.

Discussion point: Reducing fertility in high-fertility countries is not an especially important priority for tackling climate change.

Family planning programs and the fertility decline slowdown.

Dr O’Sullivan asserts that the slowdown in the global fertility decline is caused by less investment since the 1990s in voluntary family planning programs. She mentions a few countries where lower FP investment was followed by stagnating decline or rising fertility, but I’m not sure that she provides convincing evidence that this is the main reason for the slowdown that shows up in the overall global figures. I suggested that another possible explanation was artefactual – essentially, it’s easier to reduce fertility when people are having a lot of children than it is when fertility approaches two or less children.

I did a bit of analysis on the World Development Indicator dataset that I think is at least broadly suggestive that this may be so. First, taking the nine highest fertility African countries mentioned above, it turns out that their fertility decline hasn’t slowed but increased since the 1990s and in fact this is also true on average for the fifty countries in the world with the highest current fertility rates – albeit more true for the ones at the top of that distribution than the bottom, which further lends prima facie support to the artefactual explanation. The overall average for these countries was a fertility decline of 0.85 births between 1983 and 1999 and 1.06 births between 2000 and 2016. But looking at the fifty countries with the lowest current fertility, the 1983-99 decline was 0.69 births whereas the 2000-16 decline was only 0.06. So it seems that it may be the low rather than the high fertility countries driving the overall decline, as you’d expect from the artefactual explanation. I don’t know how plausible this explanation is, but on the face of it I’m not sure it’s less plausible than the notion that the global slowdown in fertility decline that’s occurred (except, apparently, in the high-fertility countries) stems mostly from less FP funding.

In global absolute terms, I’m guessing China is significant – its fertility rate bottomed at just under 1.5 births per woman in 1999 and has since risen to over 1.6, which in view of its population size is probably a lot of extra people. Presumably this is because of the relaxation of its population control policies, which in a sense might confirm Dr O’Sullivan’s line of argument – though since she emphasizes voluntary population control I’m not sure how far to concede this point… Certainly, before leaping to the conclusion that the slowdown is a FP policy failure it seems to me necessary to address artefactual possibilities, as well as other possible factors (growing inequality and civil conflict maybe?)

More generally, it seems to me difficult to isolate the effects of FP programs on global fertility as completely independent, exogenous effects that can be separated from wider governmental and civil society structures and from the agency of target populations. Writers like Banerjee and Duflo3 emphasize the complexity of family planning interventions, the independent agency of the poor and the complex links to fertility quite cautiously. One of their points – much along the lines of Jan Steinman’s comment – is that children are often a pension plan, and will most likely keep being produced in quantity so long as alternatives relying on more money remain unavailable. So while I’d acknowledge that I should have taken FP programs more seriously than I did in my original post, I think the issues are more complex than Dr O’Sullivan seems prepared to entertain.

Incidentally, the ten countries that have experienced the largest drop in their fertility rates since 2000 are Afghanistan, Ethiopia, Yemen, Nepal, Sierra Leone, Rwanda, Djibouti, Guatemala, Lao and Timor-Leste. And of the ten highest fertility countries mentioned above, six of them come into the top quarter of the global draw in terms of post-2000 fertility decline, and all of them in the top half. I think there’s food there for some alternative theories of fertility decline than a singular emphasis on FP programs. Civil conflict seems to be a missing variable in much of the discussion about fertility.

Discussion point: to what extent is it possible to argue on the basis of available evidence that formal FP programs have been the main cause of the fertility decline?

Population and farm fertility

In her response to me, Dr O’Sullivan wrote “With too many people, low-impact mixed farming is no longer an option. Nitrogen fertilizer becomes essential”. I didn’t pick up on this point in debating with her because it didn’t seem important to the main lines of argument, but it’s important to the overall concerns of this blog and I think her statement is wrong. Presumably she’s referring to synthetic fertilizer, which is not fundamentally a land-sparing input but a labor-sparing (and energy-absorbing…and often a watercourse-polluting) one. Lynn White, for example, whose book I mentioned in my previous post, makes the point that the advent of synthetic fertilizer in quantity in Chinese agriculture from the 1980s scarcely increased crop yields, but it released a lot of agricultural labor for industrial activities. Population density in itself is not a major driver of the shift from ‘low-impact’ farming to synthetic fertilizer farming. My prediction is that with rising population, rising energy costs and stalling economic growth over the coming decades we’ll see a decline in synthetic fertilizer use and an increase in labor-intensive mixed farming.

Discussion point: With ‘too many’ people, rising energy prices and falling economic growth, low-impact mixed farming is likely to become the dominant form of agriculture in the future.

Population and land availability

If population increases, then other things being equal the amount of agricultural land available per capita will decrease. Historically, the main ways people have responded to that dynamic are:

  1. clearing more wildland for agriculture (not a good idea in our present world)
  2. lowering their fertility
  3. intensifying agricultural production (more labor per hectare, less meat etc.)
  4. importing food from elsewhere
  5. migrating

My country, Britain, comes reasonably low down the list of countries ranked by agricultural land area per capita (127th out of 209 countries, at 0.3ha per person). Historically, it’s followed all five of the procedures above. In the past, (5) has been one of its main strategies – one reason why there are now so many white folks in countries like the USA and Australia. Nowadays, (4) is one of its main strategies. Despite the pressure on land, there’s little talk about (2) in UK policy circles (though elsewhere in Europe, where fertility is lower than the UK, there are converse policy worries about demographic decline). Interestingly, many of the highest fertility African countries are quite high up in the top half of the list, with a lot of agricultural land available per capita – though I daresay one shouldn’t infer too much from that. Right up there in third place is Australia, with 15ha of agricultural land per person.

A question that nags at me is why, when it comes to discussing pressure on agricultural land in Africa, does point (2) always figure so insistently in the discussion? Not that (2) is a bad idea at all – but why do we hear so much less about, say, (5) – perhaps by establishing a migration program from Burundi to Australia, for example? I think it would be interesting to discuss why (2) seems to be regarded as ‘lower-hanging fruit’ for a country like Burundi than (5), and why (4) seems to be so favored in the UK.

Discussion point: what is the best way of ordering priorities among the five responses to decreased per capita farmland availability listed above? Does it vary from country to country, and if so on what grounds?

Resource availability per capita

Dr O’Sullivan writes that there is a “mathematical simplicity of population growth reducing natural resources per capita”. However, this point has been explicitly disputed from at least the 19th century down to the 21st by a long line of land economists, anthropologists and rural sociologists. This remains true whatever Dr O’Sullivan’s opinions are on Henry George’s religious views. I’m not saying that all these thinkers are correct in all their analyses. But my contention is this:

Discussion point: the relationship between population growth and available natural resources per capita is not mathematically simple (depending, I suppose, on how you define a ‘natural resource’…and also how you define ‘simplicity’).

Absolute and relative measures

There was quite a lot of toing and froing around absolute versus relative measures of this and that in my debate with Dr O’Sullivan. Some of her presentations of evidence strike me as pretty misleading, whereas others are potentially illuminating. I’m still not sure whether the relative increase in absolute population growth since 2000 is one of the illuminating ones or not. I’d be interested in any other views. As mentioned above, it seems quite likely that events in China are a major driver for this – and if so it may be the per capita environmental impacts rather than population numbers which are the ‘lowest-hanging fruit’ in this instance.

Discussion point: what can we infer from the relative increase in absolute population increase since 2000?

The right and the wrong of it

Dr O’Sullivan wrote of me “You argued that fertility was declining without any interventions to promote it, and that it would soon cause population to peak and decline, and that we could not effectively do more to influence it, and that we didn’t need to. I am arguing that these are demonstrably false positions.” Perhaps this sounds like sophistry, but I’m not sure that claims about the future, about the efficacy of something that we’re not actually doing and about normative priorities can be ‘demonstrably false’. Still, in the light of our exchange I’d certainly accept that I pressed those positions further than is warranted. I suppose eating some humble pie once in a while is a risk I must take in return for tossing my worthless opinions so vaingloriously into cyberspace on a regular basis. What makes it harder to do is Dr O’Sullivan’s charmlessly one-dimensional focus: firstly on only one part of my argument, secondly and more importantly on what seems quite a questionable take on population, development and the environment, and thirdly and more importantly still on some of her own highly problematic statements that lead us into other worlds of trouble.

Discussion point: “Over the last fifty years, fertility has crashed at a historically unprecedented rate, though it’s been a bit less unprecedented at the end of that time period than at the beginning (except in high-fertility countries where the decline has not leveled off) – and I should have addressed that”.


The exchange that Dr O’Sullivan and I had (with a few contributions from others – thank you) can be found hereherehereherehereherehere and here.


  1. Sinding, S. 2009. Population, poverty and economic development. Phil. Trans. R. Soc. B 364, 3023–3030.
  2. Casey, G. & Galor, O. 2017. Is faster economic growth compatible with reductions in carbon emissions? The role of diminished population growth. Environ.Res.Lett. 12 014003
  3. Banerjee, A. & Duflo, E. 2011. Poor Economics. Penguin.


Teaser photo credit: CC BY-SA 3.0