Dissecting those ‘Overpopulation’ Numbers: Part One – Population Where?

Is global warming caused by too many people? This begins a series of articles in which Climate & Capitalism editor Ian Angus shows that population numbers can conceal far more than they reveal.

See also
Part Two: The Perils of Per Capita
Appendix to Part Two: Rates and Ratios

by Ian Angus

A recent Washington Post article criticized three new books on global warming because “none of these authors discusses population growth in any kind of depth.”

To reduce emissions, the reviewer wrote, we should be “helping people to have smaller families …[by] providing the means for family planning to those who want it but don’t have access.” That, he assures us, is “a lot easier than retooling the global economic system.” [1]

Like many environmentalists, the Post writer firmly believes that population growth worsens global warming by increasing greenhouse gas emissions, and that the solution is to slow or reverse population growth by providing birth control to people “who don’t have access” – that is, to people in the Third World.

And yet, anyone who carefully reads the many websites, articles, speeches and books that argue the “too many people” thesis will find that they offer little or no evidence to support such conclusions.

That’s not to say that they don’t offer impressive arrays of facts, usually in the form of a scary paragraph about global population growth.

This, from Optimum Population Trust, is typical:

“The world’s population is still exploding. Human numbers, which reached 6.8 billion in 2009, are expected to reach 9.15 billion in 2050, and we’re growing by 78 million a year. The 2.3 billion increase from 2008 to 2050 is almost as much as the entire population of the world in 1950 … Every week 1.58 million extra people are added to the planet – a sizeable city – with nearly 10,000 arriving each hour.” [2]

And so is this, from Global Population Speak Out:

“It took virtually all of human history for our numbers to reach 1 billion in the 1800s. It took only about a century to add the second billion in 1930. We added the third billion in just 30 years and the fourth in only 15 years. We are now at 6.7 billion with projections of over 2 billion more to come in the next 40 years. The size and growth of the human population is linked closely to nearly all forms of environmental degradation we see today.” [3]

Such statements – many more could be quoted – present gross population figures as the most important measure of humanity’s impact on the earth. Advocates of population reduction rarely take their analysis any further. When it comes to human numbers, populationist arguments begin and end with big is bad and bigger is worse.

Correlation isn’t causation

Typically, such arguments point to the substantial increases in both population and greenhouse gases in the past two centuries, and conclude that emissions growth has been driven by population growth.

The underlying argument is summarized in a recent textbook on climate change:

“Generally, if one person has an environmental impact of some arbitrary quantification, x, then it is not unreasonable to suppose that two people will have an impact of 2x, three people an impact of 3x, etc; in other words, that environmental impact is proportional to population ….”[4]

But this simplistic logic only works if every additional person causes the environmental impact to increase by “some arbitrary quantification, x.” The populationist argument assumes that, but doesn’t prove it.

At some point in every introductory statistics course, the instructor tells students about a European city where increases in the stork population were supposedly matched by increases in the number of new babies. The point is, that correlation isn’t causation – storks don’t bring babies, no matter what the numbers say.

This lesson is all too rarely applied to debates on population and emissions. To determine whether population growth really drives emission levels, or if the correlation is a coincidence, or if the numbers are in some other way misleading, we need to go beyond big numbers and examine real connections and relationships.

With population, the correlation-or-causation problem is further complicated by the fact that big scary numbers (6.7 billion people, 10,000 births per hour) actually tell us very little unless we examine them in context. Population statistics are useful only if we understand how they are determined, what they include and what they leave out, what their strengths and limitations are for any specific purpose. As Karl Marx wrote 150 years ago, “population” is an abstraction, not a real thing.

“It seems to be correct to begin with the real and the concrete, with the real precondition, thus to begin, in economics, with e.g. the population, which is the foundation and the subject of the entire social act of production. However, on closer examination this proves false. The population is an abstraction if I leave out, for example, the classes of which it is composed.” [5]

This is a profound insight, one that activists who are concerned about the complex relationship between humanity and the world we live in must understand. “Population” is just a number, one that can conceal far more than it reveals. To understand the relationship between “population” and climate change, we need to dissect the big numbers.

Population where?

As a first step towards exposing the concrete reality behind the abstraction, this article considers some differences between rich and poor countries that the “too many people” argument usually ignores. The table below compares two groups of countries:

  • The G20 countries, self-described as “the systemically significant industrial and emerging-market economies.” These countries include two-thirds of the world’s population and account for 90% of the world’s Gross National Product. [6]
  • The 19 countries with the lowest per capita CO2 emissions. All but one (Afghanistan) are in Africa.

In each group, the countries are listed in descending order by Per Capita CO2 emissions in 2006, the most recent year for which I could find numbers.

The second column from the right shows population density – the average number of people per square kilometre. This is a rough measure of how “populated” (over or under) the country is.

The right-hand column shows how fast the population is growing. “Total Fertility Rate” is the number of children, on average, born to each woman in the country during her lifetime. The higher this number is, the faster the country’s population is growing. The Total Fertility Rate at which a country’s total population would be stable, not growing or declining, is generally taken to be about 2.3 – ranging from 2.1 in rich countries where infant mortality is lowest, to as high as 3.3 in the global south.

CO2 Emissions, Population Density, and Total Fertility Rate
CO2 Emissions Population
Per Capita (tonnes) Total
(million tonnes)
(per sq. km)
Fertility Rate
G20 Countries U.S.A. 19.7 5975.1 30.71 2.05
Australia 19.0 390.44 3.0 1.79
Canada 17.2 560.39 3.0 1.53
Saudi Arabia 15.78 381.56 13.47 3.35
Russia 11.0 1577.69 8.0 1.34
Germany 10.7 880.25 230.89 1.36
Japan 10.0 1273.6 337.23 1.27
South Korea 9.89 475.25 491.7 1.21
U.K. 9.2 557.86 246.88 1.82
South Africa 8.59 414.65 36.35 2.64
Italy 8.3 488.04 192.89 1.38
France 6.7 408.69 110.88 1.89
China 4.62 6103.49 136.12 1.73
Argentina 4.43 173.54 14.29 2.25
Mexico 4.14 436.15 53.84 2.21
Turkey 3.7 273.71 89.24 2.14
Brazil 1.86 352.52 21.86 1.9
Indonesia 1.46 333.48 126.06 2.18
India 1.31 1510.35 328.59 2.81
Total CO2 Emissions 22566.76
Low Emission Countries Sierra Leone 0.17 0.99 83.88 5.0
Madagascar 0.15 2.83 30.73 5.14
Guinea 0.15 1.36 38.51 5.2
Tanzania 0.14 5.37 38.9 4.46
Eritrea 0.12 0.55 37.6 5.05
Mozambique 0.1 2.04 24.21 5.18
Uganda 0.09 2.71 115.53 6.46
Rwanda 0.08 0.8 320.48 5.12
Malawi 0.08 1.05 102.62 5.59
Niger 0.07 0.94 9.0 7.75
Ethiopia 0.07 6.01 64.81 5.29
Central African Republic 0.06 0.25 6.0 4.14
Mali 0.05 0.57 9.91 6.62
Burkina Faso 0.05 0.79 50.79 6
Dem. Rep. of Congo 0.04 2.2 25.62 6.2
Chad 0.04 0.4 8.0 5.31
Afghanistan 0.03 0.07 46.22 7.07
Somalia 0.02 0.17 13.47 6.04
Burundi 0.02 0.2 228.91 6.33
Total CO2 Emissions 29.3
Emissions Source: United Nations Statistical Division. CO2 Emissions in 2006. http://unstats.un.org/unsd/environment/air_co2_emissions.htm
Fertility Source: World Population Prospects The 2006 Revision. (PDF)http://www.un.org/esa/population/publications/wpp2006/WPP2006_Highlights_rev.pdf
Pop. Density Source: World Atlas. http://www.worldatlas.com/aatlas/populations/ctydensityh.htm

This table leads to three inescapable conclusions.

1. CO2 emissions are a problem of rich countries, not poor ones. The G20 countries produced more than 22,500 million tonnes of CO2 in 2006. That’s 78% of the worldwide total – nearly four times as much as all other countries combined. It is more than 770 times as much CO2 as the 19 lowest emitting countries produced.

Per capita CO2 emissions in the United States are 98 times greater than in Gambia, 132 times greater than in Madagascar, 197 times greater than in Mozambique, and 400 times greater than in Mali or Burkino Faso.

These figures, it’s important to note, significantly understate the case, because they don’t include some of the major emission sources that are concentrated in rich countries, such as military activity and international air travel.

So the idea that “providing the means for family planning to those who want it but don’t have access” will somehow slow global warming makes no sense. With few exceptions, birth control has long been available in the countries that are doing the most to destroy the earth’s climate.

2. There is no correspondence between emissions and population density. The high-emitting G20 group includes countries such as India, Japan, and South Korea, which are home to high numbers of people per square kilometer – but it also includes countries with low population density, such as Australia, Canada and Russia.

Exactly the same is true of the low-emission group, which includes countries with high population density (Rwanda, Burundi) and countries with low population density (Niger, Chad).

So it is clearly possible to have low population density with high emissions, or high population density with low emissions.

It’s also worth noting that almost all of the low-emission countries have far fewer people per square kilometre than the United Kingdom, where Optimum Population Trust is promoting Third World birth control as a means of slowing global warming. [7]

3. Population growth rates do not correspond to CO2 emissions. In fact, there’s a negative correlation. Broadly speaking, the countries with the highest per capita emissions are those whose population is growing most slowly or even declining, while the countries with the lowest emissions have the highest growth rates.

In fact, in most G20 countries the birth rate is at or below replacement level. If it weren’t for immigration, their total population would be falling. According to some estimates, by the end of this century the population of Italy (excluding immigration) will fall by 86%, Spain will decline 85%, Germany 83% and Greece 74%. [8]

Only three G20 countries (Saudi Arabia, South Africa, and India) have fertility rates that are clearly above replacement level, and even they are growing far more slowly than the 19 lowest emitting countries.

If we were to adopt the usual populationist correlation=causation stance, we’d have to conclude that high emissions cause low population growth, or that high population growth causes low emissions. Of course that’s absurd: both emissions levels and population growth are shaped by other social and economic causes.

The real conclusion is, that there’s something seriously wrong with the more people equals more emissions argument, and something even more wrong with the idea that Third World birth control will slow global warming. [9]

As John Bellamy Foster has pointed out:

“Where threats to the integrity of the biosphere as we know it are concerned, it is well to remember that it is not the areas of the world that have the highest rate of population growth but the areas of the world that have the highest accumulation of capital, and where economic and ecological waste has become a way of life, that constitute the greatest danger.” [10]

And as environmental writer Fred Pearce writes in his recent book Peoplequake:

“The poorest three billion or so people on the planet (roughly 45 per cent of the total) are currently responsible for only 7 per cent of emissions, while the richest 7 per cent (about half a billion people) are responsible for 50 per cent of emissions.

“A woman in rural Ethiopia can have ten children and her family will still do less damage, and consume fewer resources, than the family of the average soccer mom in Minnesota or Manchester or Munich. In the unlikely event that her ten children live to adulthood and all have ten children of their own, the entire clan of more than a hundred will still be emitting only about as much carbon dioxide each year as you or me.

“So to suggest, as some do, that the real threat to the planet arises from too many children in Ethiopia, or rice-growing Bangladeshis on the Ganges delta, or Quechua alpaca herders in the Andes, or cow-pea farmers on the edge of the Sahara, or chai-wallas in Mumbai, is both preposterous and dangerous.” [11]

Preposterous and dangerous. Amen.

To be continued



[1]Thomas Hayden. “Environmental books suggest save-the-Earth climate may be entering a new phase.” Washington Post, April 20, 2010. Accessed April 21, 2010 at http://www.washingtonpost.com/wp-dyn/content/article/2010/04/19/AR2010041903186.html

[2] Optimum Population Trust website. Accessed April 10, 2010 at http://www.optimumpopulation.org/opt.earth.html

[3] Global Population Speak Out website. Accessed April 10, 2010 at http://gpso.wordpress.com/resources/

[4] Jonathon Cowie. Climate Change: Biological and Human Aspects. Cambridge University Press, Cambridge, 2007. p. 310

[5] Karl Marx. Grundrisse: Introduction to the Critique of Political Economy. Penguin Books, 1973. p. 100

[6] Despite its name, the G20 includes only 19 countries – the twentieth member is the European Union, which is omitted from this table to avoid double-counting.

[7] Optimum Population Trust recently launched a program called PopOffsets that lets people in rich countries “offset” their emissions by contributing to birth control programs in the Third World. OPT particularly mentions a program in Madagascar, which is one of the 19 lowest-emitting countries.

[8] Fred Pearce. Peoplequake: Mass Migration, Ageing Nations and the Coming Population Crash. Eden Project Books, London, 2010. p. 122

[9] To avoid misunderstanding: I strongly support making birth control, abortion and other maternal health services available to women everywhere, as a basic human right. What I oppose is blaming third world women for global warming, and promoting reduced fertility as a solution. That’s not only inaccurate, it has dangerous implications, as the history of population control programs in the last 40 years has shown.

[10] John Bellamy Foster. Ecology Against Capitalism. Monthly Review Press, New York, 2002. p. 152

[11] Fred Pearce. Peoplequake. p.242.

Posted in Featured, Population

Sort by:   newest | oldest | most voted
4 years 9 months ago

> So the idea that “providing the means for family
> planning to those who want it but don’t have
> access” will somehow slow global warming makes no
> sense. With few exceptions, birth control has
> long been available in the countries that are
> doing the most to destroy the earth’s climate.
The more I think about this the more infuriated I get. If you have never had a late period, never forgotten to take a birth control pill, never had to have the IUD taken out because of cramping, don’t you DARE say this.

4 years 9 months ago

Indeed, population growth in the third world doesn’t increase greenhouse gasses significantly, but this does NOT mean that we shouldn’t be working frantically to decrease population growth in countries like the U.S. and Australia. There is a new vogue for large families among the richest Americans, and you can be sure the upper-middle-class wants to emulate these folks. How can you say this won’t affect the environment?

4 years 9 months ago

With few exceptions, birth control has long been available in the countries that are doing the most to destroy the earth’s climate.” True, but
so-called “availability” is no easy thing. Social pressures, lack of childcare when visiting clinics, occasional shortages of cash to pick up prescriptions; abusive men who sabotage their partners’ birth control — all these are huge factors in countries like the U.S. Our entire evolutionary history has conspired to maximize our fertility, so don’t assume stopping fertility is easy or simple.
Read “Quiverfull.” Work in a birth-control clinic. Counsel pregnant teens: We could be doing a far better job. In fact, our future demands it.

Jeff White
4 years 10 months ago

John Meyer’s views on immigration are of course greatly admired by people such as Tim “So what if I’m racist?” Murray of the right-wing, xenophobic Immigration Watch Canada.

His methodology is of course faulty. He takes cumulative immigration statistics and multiplies them by the per-capita emissions of the Canadian population as a whole to come up with a completely theoretical figure for how much immigration has added to Canada’s emissions. Per-capita emissions in Canada, however, include each person’s per-capita “share” of the tar sands emissions themselves; any real comparison with the tar sands themselves would first have to take out the tar sands component of the per-capita statistics.

But the comparison itself is phony in any event. Per-capita emissions include emissions over which individuals, whether they be immigrants or not, have no control, the tar sands being just one of them. Emissions caused by forestry, agriculture, steel mills, mining, manufacturing, trucks, trains, aircraft, and many other sources are all included in the per-capita emissions statistics. They are emissions that would take place anyway, with or without the arrival of immigrants to this country.

Ian has dealt very well with the issue of “per capita” emissions in Part 2 of the above article.

John Meyer
4 years 10 months ago

In the G20, population growth goes drives a substantial amount of the environmental impact growth. In Canada, mass immigration has had, since 1990, 2 1/2 to 3 times the impact of the oil sands on Canada’s Kyoto target overshoot.

I don’t know how you can possibly invent a measure like density and relate it to carbon emissions. They aren’t related, period. It’s like the right wing red herring of “intensity” which takes something real (carbon emissions) and relates it to something unreal (money) and comes up with a measure which effectively makes dealing with the real issue impossible.

Population growth is a bedrock right wing priority. It is their cash cow and drives their market size and structure. It is the anti-well-being / equality index.

If you could get Marx on the phone to comment on this today, I doubt he’d phrase things quite as you have in this context.

You are putting words in a dead man’s mouth.

John Meyer

David Bacon
5 years 11 months ago

I have a somewhat simpler viewpoint, modeled in part by Albert Bartlett’s question – can anyone think of a problem, large or small, that is made better by a larger population? I was born in 1941 and my memories of life in any detail extend back to about the time I was in high school and thereafter. The population when I finished high school in 1959 was less than half what it is today and today like most days as I drive or walk through town or try to make an airline reservation or do anything that others also are doing I think about how nice it would be if there were half as many of us as there actually are.

Kim Bergström
6 years 21 days ago

I should also add that I think you open yourself to the same sort of criticism your are dishing out. Seeing a correlation between present population and present emission and drawing conclusions about how *changes* in population would or would not *cause* a *change* in emissions is not the same thing I’d say.

Kim Bergström
6 years 21 days ago

To say that a doubliong (say) of the population would have no effect (or thereabouts) on CO2 emission opr ecological fottprint seems … a bit of a stretch. Of course, we cant focus solely on population, as you point out. But to imply that the number of consumers have nothing to do with the ammount being consumed seems … silly.

John Rawlins
6 years 22 days ago
If you blend your analysis with facts concerning world food production, the dependence of food production on oil and natural gas, the strong correlation between oil/gas production and population increase during the 20th century, and the highly likely near-term peaking and decline of world oil production, then I suspect you will conclude (as I have) that world population a century from now will be far smaller (1-2 billion?) than it is now. There is increasing certainty that world oil production (followed shortly by peaking of gas production) is now near peak and that the decline will negatively impact everything else, including food. After reading through some of Garrett Hardin’s work on over-population, combined with William Catton’s books “Overshoot” and “Bottleneck” and a huge collection of online articles at The Energy Bulletin and The OilDrum, I am convinced that peaking of oil and natural gas will take care of world population overshoot, very likely in highly unsavory ways, in the course of the 21st century – beginning within a decade. The only way I can imagine to mitigate, to some extent, population collapse is to promote massive changes to world food production methods that might work in a post-carbon world –… Read more »
6 years 22 days ago

The fact that people with higher fertility rates happen today to be low carbon emitters may be a temporary condition.

I think it’s safe to assume those with a very small slice of the pie want and deserve a larger slice. The number of people getting a slice of the pie will impact whether a slice of pie will sustain you. The pie isn’t getting any bigger; in fact it’s getting smaller.

So, while we work to get to more equal slices of the pie, we would be smart to encourage those with big slices currently AND those with small slices to think about the pie slice size implications of their family size decisions on their children and other members of the next generation.

I suppose one can find populationists with the narrow views attributed by Mr. Angus. But I encourage Ian and others here to be open-minded about this issue and worry less about motives they cannot ascertain, and worry more about what a fair and just world will look like. Will it look better at 9, 12 or 15 billion? Or will it work better at 7?

Dave Gardner

N. Eason
6 years 23 days ago

Okay, so let’s agree that population numbers are not a problem and do not need to be tackled.

You conveniently avoided responding to my questions: how do you propose to reduce consumption in G20 countries then? Or is the per capita consumption level also not the cause of the problem. I guess I’ll have to wait to read part 2.

You may be right. Meanwhile Rome burns.

Robert Beck
6 years 24 days ago
I’m not sure where the idea came from that its either population or consumption that is the problem. Of course it is both. If America only had 100 million people consuming at the current rates, then we would not have nearly the same impact as we do at 300 million. The world could probably easily support 500 million people living at our standards. The effect of a population on the world is relative to their consumption patterns. And this is consumption not just of fossil fuels that directly produce green house gases but of all the other resources like fresh water, raw materials, land use for agriculture, waste and pollution, effects on biodiversity and so on. You could create an argument that population is not a problem by focusing on one of these consumptive items, like fossil fuel use. But this is a simplistic and artificial argument. For instance, land use for agriculture is probably more directly linked to population size than is fossil fuel use. People need to eat. They require so much soil and arable land to produce those foods. You can reduce the diet to the most efficient use, such as growing potatoes for human consumption rather… Read more »
N. Eason
6 years 24 days ago

Population Where? you ask. Pretty clearly from your table, it is the G20 that must reduce its total emissions, bringing it down from 78%. There are two ways to do that: reduce the population in the G20 or reduce the per capita numbers. Preferably both.

What programs are required to reduce the population in the G20? Fertility rates are already pretty low, so that seems covered. That would leave immigration, a topic just as prickly as population.

What programs are required to convince each individual of the existing population to reduce their emissions? People are going to have to give up something. Do we pass legislation which can be coercive or provide incentive, or do we mount some kind of education campaign to convince them of this fact. But will they be convinced?

In the end, both these approaches are likely just as difficult, one as the other. Tackle both and hope to get enough gains in both to reduce the total emissions of a given country by “enough”.

6 years 24 days ago
Nice piece. I take the perspective that the issues of population and emissions ARE related, but they are both aspects of a greater meta-issue – that of how mankind views its place in the larger reality as an element of a global ecosystem. H.sap.sap tries to get by in the most comfortable way possible. In places with low access to resources and knowledge this leads to population boom (comfort #1 = finding a pleasurable experience when the sun is down and there is too little light to do much…beliefs and/or lack of contraception are the enablers); where as in areas rich in technology and resources (either indigenous or imported) there is a meme pushing individuals to seek material rewards leading to resource consumption and the resultant pollution. The increases in the population in the “Global South” are further enabled by the attempts to provide outside aid. The increase in pollution/consumption in the “North” is further enabled by a combination of increasingly clever ways to extract, refine, engineer and design resources and a system of regulation largely amenable to (primarily centered around?) a financial system essentially built on trust of individuals who are corrupted by too much power and the concomitant… Read more »
Randy Serraglio
6 years 25 days ago
This article is compromised from the get-go by falling into the same old trap of framing the issues of climate change and unsustainable human population growth in terms of national boundaries. These are global issues that need to be addressed globally. Population dynamics are biological, i.e., how many people can the planet support and still maintain sufficient ecological viability to provide a quality life for ALL species, not just humans. Moreover, there are assumptions in the article that are simply not true. For instance, plenty of people in the U.S. do not use birth control for a variety of reasons: 1) they don’t have health insurance, 2) it is not covered by the insurance they do have, 3) they cannot afford it, 4) they face cultural resistance to it (often religious), 5) they face oppressive gender dynamics, and so on. Yes, it is very important to curb population growth here in the U.S., and yes, there are millions of people here who would benefit from improved access to birth control/family planning. Why are some people so compelled to cry “racism” every time they hear the word “overpopulation”? Trying to draw national boundaries around these issues is a recipe for finger-pointing… Read more »
6 years 25 days ago

Thanks for your welcoming words, Ian.

I agree wholeheartedly that the public debate about population and climate change is lacking in nuance and awash in misinformation. And there is certainly a temptation to see population as an “easy out,” a solution to the climate crisis that demands no real sacrifice on our part.

I would much rather see Brian O’Neill’s nuanced, data-driven approach informing the debate. But I think you misunderstand the conclusions of his work. O’Neill doesn’t claim that population growth drives emissions growth, but he does show that it makes a significant contribution. Like many emissions-reduction strategies we could embark on today, the impact of slowing population growth will start out small and grow over decades. That doesn’t mean they’re not worth doing.

Slowing population growth is not a “distraction” or a substitute for meaningful action on climate change. There are many, many actions we must take immediately to avert catastrophe. Slowing population growth—by making sure that all people have the means and the power to make their own decisions about childbearing—is one of them.

6 years 25 days ago
Of course aggregate population growth numbers mask staggering differences in per-capita environmental impact. And of course it is preposterous to claim that rapid population growth in the poorest countries is driving climate change today. No serious researcher studying the population-climate connection would make that claim. Yet those researchers do not dismiss the role of population growth, as you do. In fact, Brian O’Neill at the National Center for Atmospheric Research has shown that slowing population growth would have a significant impact on future carbon emissions. In your analysis, the inequitable divide between rich and poor remains fixed for all time. But when you consider that developing countries are, in fact, developing, it becomes apparent that population growth does matter for climate change. While the countries with the highest fertility are developing very slowly (there is a strong correlation between poverty and rapid population growth) there are also countries—notably India–where both population and carbon emissions are growing rapidly. O’Neill’s research shows that stabilizing world population at 8 billion, rather than 9 billion or more, would keep about 1 billion tons of CO2 per year out of the atmosphere by 2050. Nearly half of that reduction in CO2 would come from India.… Read more »