What’s humanity’s golden number?

Growing up my dad and I always used to speculate and attempt to solve the world’s problems during our road trips. We always ended up at the same conclusion – there are simply too many people in the world, as if the world had a golden number, a carrying capacity if you will, after which it is only a matter of time before we fall into a malthusian catastrophe.  As I have had the chance to travel to and live in different parts of the world, I came to the realization that this issue of a carrying capacity is far more complex than simply having a straightforward answer.

As I spent the last few years meandering about in these different cities, it became increasingly obvious that there was no such golden number. The lifestyles of populations around the world and even within cities differ far too significantly to count each as the same. In other words, although the value of the life of a child born to a poor family in a South African township is morally the same as a child born to a wealthy family in the Upper East Side of New York, their predicted carbon footprints and consumption over their lifetime is oceans apart. And it is this very fact, which this golden number does not consider.

Measuring standards of living or the impact of a particular lifestyle is an almost impossible task. In my argument that follows, I will equate standard of living with the carbon footprint of the individual in that higher standards of living have higher carbon footprints and lower standards of living are equated with lower carbon footprints. As I anticipate dissent to this approach, I want to make it clear that I acknowledge this method is not perfect, but I do still believe it provides significant insight. Yes, there are exceptions in that some individuals that are poor manage to still have higher carbon footprints than some wealthy people that are obsessed with limiting their own carbon footprint. However, an exception is exactly that, something which is rare, an outlier and should be omitted when we are addressing trends of the global population.

I do not wish to get too mathematically complex, however a few simple equations could make my explanation smoother. If one were to create a very simple model of the world’s carrying capacity (CC), it would be determined by number of people (P) and the average lifestyle at which they lived or their carbon footprint (CF). Now in such a model, and only in such a model, there would be a Golden Number for each and every level of average consumption. If the model appeared as CC = PxCF then if the carrying capacity was 20 units and the average carbon footprint was 2 units, our golden number would be 10 people. However, if our average carbon footprint per person increases to 5 units, the golden number becomes 4 people. Therefore this model does have a golden number. Unfortunately, the world does not have one single standard of living at which all its people live, making such a golden number impossible.

So when people ask me, do you think the world is overpopulated? I respond, if people are willing to live the way hundreds of millions of people in Asia or Africa are living, with a comparatively negligible carbon footprint, then the world is not even close to capacity. However, what is significantly more scary is that, if the whole world wishes to live the way citizens of the developed world are living (which is actually the case) we passed our golden number decades ago.


To make our model slightly more realistic, we can introduce classes: Let’s say lower-class (LC), middle class(MC), upper-middle class (UMC) and upper-class (UC) so that the model looked like: Global Footprint = 1xLC + 2xMC + 6xUMC + 20xUC where the global carbon footprint was unable to exceed the carrying capacity without causing devastating effects, and the coefficient before each class would be the impact on the global footprint of an additional individual in that class. What one would notice by inspection is that the impact of another lower-class child being born on our total carbon footprint is essentially negligible. The places in the world where we are seeing rapid population growth, fortunately for this scenario, are the poorest areas where child mortality rates are still unacceptable but quickly improving. What is also fortunate is that the areas of the world where the economies and societies are most advanced, with the greatest carbon footprints per individual, population growth is very slow and stable.

What however is heart warming on one hand but incredibly concerning on the other, is the rising upper middle class all throughout the world, although predominantly in China and India. This improvement of living standards will rapidly reduce our ‘golden number’ as the global average carbon footprint skyrockets. This means that as more and more households join the middle class, the less individuals the world is able to sustain. To explain this, a rise in standard of living moves individuals from the LC or MC bracket to the UMC bracket. This means that for a family of 4 to leave poverty and join the upper middle class is the equivalent (at least in this model) of 20 people added to the LC bracket, in terms of its impact on our total global carbon footprint and hence carrying capacity. Although this model and its coefficients are fictitious, the truth is not far from it. Matthew Connelly, a historian at Columbia University, puts the average American consumption around six times that of the global average, indicating that this simple model is not that far off from the truth.

The implications of the rise of the upper middle class are somewhat scary when they are laid out in front of us. We cannot sit back and do nothing, as the consequent rapidly growing carbon footprint, cannot be sustained by the earth’s resource availability and carbon sinks. In fact, left unchecked, a Malthusian Catastrophe of some form might be well on its way. What then is the way forward for humanity, to ensure we do not lead to our own extinction?

There are several ways in which we are able to avoid catastrophe, some more realistic than others. Two unrealistic ways to limit the global carbon footprint would be for a non-benevolent global dictator to create a global caste system in which one could never leave their class or increase their standard of living as this would put the global balance in jeopardy. Secondly, those living at the top, would have to reduce their living standards, hence their carbon footprint, so to allow the rise of the middle class without an exponential growth in the global footprint. The reduction of consumption by the upper class would be offset by the rising middle class to keep the global carbon footprint constant. Neither of these situations are incredibly likely.

Solar Fram

What’s the third and only real solution? We need to reduce the carbon footprint at which our standard of living is brought about. Ultimately renewable energy is the key. Renewable and sustainable energy will be the largest player in reducing carbon footprints without doing away with high standards of living. The only way this ‘malthusian catastrophe’ can be avoided is if the price of solar panels and other forms of renewable energy fall just as rapidly as the world’s middle class is growing. It is left to the engineers to save the day.

Currently, energy policy is very much a political issue as many nations have vested fossil fuel interests keeping them from subsidizing renewable energy sufficiently. However, when we make the necessary advancements to make solar, hydro, wind and other forms of renewable energy cheaper than fossil fuels, not even fossil fuel interests entangled in our politics would be able to get in the way of this societal progress. It is only a matter of time, as solar farms (pictured above) are already being built around the world. A surprise to many is that China is in fact leading the way when it comes to solar energy, and I hope to see them incorporate solar farms not only in their One-Belt One-Road (OBOR) initiative but also in their infrastructure investments in Africa.


There is great optimism amongst this chaos. Underdeveloped areas in Africa and parts of South Asia, are presented with a massive opportunity to leapfrog the fossil fuel stage and start their development with renewable energy. Africa is at a distinct advantage because of its underdevelopment. Their ‘backwardness’ for a lack of a better term, provides them the opportunity to learn from the mistakes of those that have developed before them, to ultimately craft a continent, that will create envy for those peoples and nations that developed before them.

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