The Great Multiplier

By Jan van Weeren | 10 January 2023
The Overpopulation Project


At the end of 2022, the Wittgenstein Centre for Demography and Human Capital held a conference titled Population and Climate Change: The Defining Relationship of the 21st Century. Yet as one participant noted, in this presentation from the conference, the desire to downplay population’s importance is hard to avoid, even among those who should know better.

In the first paragraph of the call for papers for this conference there was a remarkable statement. It reads as follows:

Population size nevertheless matters less for human impacts on the climate and other earth systems as compared to affluence and consumption, which vary widely across the planet.

I’d like you to scrutinise this statement. The first part poses that population size matters less for human impacts on the climate and other earth systems than affluence and consumption. This is a hotly contested assertion, especially regarding ‘other earth systems’, but even if it were so, consider that without people there is no affluence or consumption. Population growth leads to increased economic activity, and as more and more people escape from poverty, they will consume more.

In the well-known IPAT equation, P (population) and affluence (A) are two of the three factors that are equally important in determining the human impact on the environment. If we define A (affluence) as the GDP (Gross Domestic Product) per capita, then a 10% increase in A and a 10% increase in P have exactly the same effect in increasing environmental impact (I). That makes intuitive sense, since more people and greater affluence both normally lead to more economic activity—the fundamental driver of our environmental impacts.

The second part of the statement asserts that affluence and consumption vary widely across the planet. That’s undeniably true. The number of relatively poor people on this planet is much larger than the number of wealthier people. The latter can be especially found in North America, Western Europe, Australia, and in countries such as Japan, South Korea and Saudi Arabia, all countries for which the GDP per capita exceeds 30K dollars.

Approximately the number of well-to-do people will hardly exceed 1 billion. Let’s consider all the others as the poorer people of the world. Their number will add to 7 billion. No one of them will be willing to stay poor. People traveling by bike, would like to have a moped, those with a moped would like to have a car, a refrigerator, a television set, or even air conditioning.

Now let’s assume that the richer part of the world would consume less in order to make consumption growth elsewhere possible without further burdening the Earth. Let the richest billion world citizens halve their consumption from let’s say 100 units to 50 units and let the other 7 billion double their consumption, from let’s say 10 units to 20 units by 2050, as their number increases to 9 billion people. Then total consumption would increase from (1 x 100) + (7 x 10) = 170 billion units to (1 x 50) + (9 x 20) = 230 billion units.

This simple calculation shows that consumption and population numbers are not separate issues. Both impact the Earth’s resources. Consuming less in rich countries, by itself, isn’t very effective on a world scale. A fairer distribution, as illustrated by the calculation, would lead to more than 35% increase of consumption in an already overburdened world.

Of course, this is merely a thought experiment and the values chosen are arbitrary. Nevertheless, it shows that as long as emerging countries such as China and India are working towards the consumption pattern of rich countries this will exacerbate the global situation. In a nutshell: the less people living here as we do, the better. And also: the less people living elsewhere as “we” do, the better, too.

It would be naïve to suppose that there is support in the developed world for cutting our consumption in half. Only a small group of self-identified environmentalists would want to do this. It is also naïve to suppose that most poor people around the world are willing to stay poor for the sake of the climate or the planet. Nevertheless, it would be a good thing if a modest lifestyle for everybody on Earth could solve the present overshoot problem.

Let’s investigate if science has an answer to this question. According to ecological footprint analysis, present day humanity exceeds the carrying capacity of planet Earth. To date, the world population overuses its renewable natural resources by a factor of 1.7. But is it our numbers or our behaviour that causes this overshoot? Should we reduce our population size or diminish our consumption? Or both?

New research has given an answer to this question. Given the universal right of a person to a standard of living adequate for the health and well-being of himself and of his family, such a standard must be set. Lucia Tamburino and Giangiacomo Bravo used the Human Development Index (HDI) of the United Nations to define such a standard.

The Human Development Index (HDI) is a summary measure of average achievement in human development. The health dimension is assessed by life expectancy at birth, the education dimension is measured by mean years of schooling for adults aged 25 years and more and expected years of schooling for children of school entering age. The standard of living dimension is measured by gross national income per capita. The scores for the three HDI dimension indices are then aggregated into a composite index ranging from 1 to 0. It is important to note that the HDI is a measure of general welfare and not just an index of material prosperity.

The HDI is calculated for 189 countries around the world. Norway has the highest HDI (0.957), Niger the lowest (0.349). Tamburino and Bravo took an HDI measure of 0.7 as a minimum level of acceptable welfare. Almost two thirds of all countries have a higher HDI value, and one third a lower one. Near the cut-off score of 0.7 we find countries such as Egypt, Indonesia and Vietnam. An HDI of 0.7 can be seen as quite a modest standard of living, at least in our Western eyes.

In order to make this HDI possible for everybody, the average person must be allowed a certain ecological footprint. According to Tamburino and Bravo, the correlated footprint is 2.14 global hectares per person. Inhabitants of rich countries consume much more than this 2.14 gha; e.g., the Austrians consume 6.1, almost 3 times more. An important component of the actual footprint of developed countries is the carbon footprint. Their greenhouse gas emissions require a lot of biocapacity to be sequestered.

Countries above the maximum per capita footprint of 2.14 gha should try to make this footprint smaller by consumption reduction, use of green energy and new technologies, in order to enable other countries to have a footprint that allows a decent standard of living.

However, the bad news is that even in a world where it is possible for everybody to have an adequate standard of living, the actual population would still exceed the carrying capacity of the planet. There are countries that could offer all their current inhabitants an adequate HDI with the associated footprint without falling into ecological overshoot, such as Canada, almost all countries in South America, Scandinavia, Russia and Australia but also Congo, Namibia and Madagascar. These are the green regions on the map below. They have an EB+, a positive ecobalance. Note that this does not mean these countries do well in other important respects, such as protecting threatened species within their borders. One example is clear-cutting old growth forests in northern forests.

Figure 1. The countries currently in positive eco-balance (the country’s biocapacity exceeds its ecological footprint) are in green. In light blue are countries with a biocapacity sufficient to provide greater than 2.14 global hectares per person (considered the threshold for an acceptable level of welfare) but requiring a reduction in consumption to achieve sustainable eco-balance. Orange countries do not have sufficient biocapacity to provide adequate consumption levels to their current population, and would need to reduce population to sustainably achieve adequate welfare per person. After Tamburino and Bravo (2021).

Then there are countries that could achieve an HDI of 0.7 within their ecological boundaries, at their current population levels, by reducing their per capita footprint. Examples are the USA, France, Ireland and Austria. These are the light blue regions on the map. They have a Potential EB+, a potential positive eco-balance.

A third category of countries, however, would not be able to do this at their current population sizes. Even if they adjusted to an HDI of 0.7 and the associated footprint, they still would exceed their ecological boundaries with their present population. These are the orange regions on the map. Examples include most countries in Africa, the entire Middle East, Pakistan, India, China and the Caribbean. But also the UK, Spain, Portugal, The Netherlands, Belgium, Germany, Poland, Switzerland, Italy and Greece.

Even if the wealthier countries in this group tried to return to ecological sustainability by reducing their per capita footprints to the size associated with a minimally acceptable HDI, they simply have too many people to achieve that goal. To create ecological balance in these countries requires both a strong reduction of production, consumption and pollution, and a substantial population decline.

What can we do to restore the eco-balance in different countries? First of all, we should try to reach an international agreement (supported by the UN) requiring each sovereign nation – that’s where the power is – to eliminate its ecological deficit, making its own trade-off between consumption and population size. No country would be permitted to “live beyond its means” by emigration or by exporting pollution. It is likely that, faced with a choice between population reduction or dramatic reductions in consumption (or other constraints), most people would choose the former, or a combination of both. Each nation could choose its favoured method of achieving sustainability.

Secondly, we should acknowledge and accept that countries with a high GDP and a high per capita footprint as well as a high ecological overshoot are not fit for immigration if they want to restore their ecological balance in the long term. More people and larger labour forces will aggravate the environmental impact of these countries (GHG, nitrogen oxides, particulate matter emissions, resource depletion, fresh water consumption, soil degradation, living at the cost of other countries by huge imports of resources). Immigrants will try to adopt the way of living in these countries and reinforce economic growth, whereas economic degrowth is required to achieve sustainability.

Thirdly, given our global addiction to fossil fuels – think of the Ukrainian War – and the worldwide inability to reduce carbon emissions, it might be better to go for adaptation to the consequences of climate change instead of investing in prevention and mitigation. Until now, energy transition and GHG reductions haven’t been very effective in developed countries. I personally believe that this ”transition” is mainly industry driven and that it functions as a corporate revenue model with numerous drawbacks (use of fossil fuels and resources to produce new e-cars, wind turbines, solar panels, dependency on rare earth metals, necessity to reinforce the grid) without any significant progress toward sustainability.

What works, instead, is economic degrowth. This can be concluded from the impacts of the COVID-19 pandemic, which postponed World Overshoot Day by a month in 2020. With billions of people striving for more wealth and just one billion people in richer countries not really willing to consume less, the whole IPCC circus seems revealed as a fake.

To give an example: the map below presents the worst-case scenario for my country in the coming centuries as a consequence of sea level rising. It will be impossible to save large parts of The Netherlands lying below or slightly above sea level. Arable land will salinize, rivers won’t be able to drain down to the sea. It might be wise for The Netherlands to start negotiations with the Federal Republic of Germany in order to become the seventeenth federal state, thus creating a broader hinterland for our inhabitants.

Reprinted with permission from Frank Götmark – Project leader of The Overpopulation Project (TORP); Professor, Animal ecology and Conservation Biology, University of Gothenburg.

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