Human population bomb

A growth chart and a proxy measure for the consumption of non-renewable resources

Update 2025: Since I first drew this graph in 2012, the population has increased by about 800k, with a current total estimate of around 8.1 billion people.

I read The Population Bomb when I was a kid. I still have the edition you see pictured below. Obviously, it made a big impact on me, and the predictions keep coming true. In my opinion, it is not a matter of if the bomb will explode, but when. So far, the saving grace has been humanity’s ingenuity, particularly the invention of modern farming practices and the Nobel Prize-winning method for creating fertilizer. But how long will our ingenuity save us?

As seen above, the world population growth chart of homo sapiens is exponential. It is estimated the planet can’t hold more than 9-12 billion people due to the photosynthetic ceiling, which means there isn’t enough sunlight or space left to grow more plants — food.

Strangely, as mentioned, fossil fuels can offset the photosynthetic ceiling. They can be used to make fertilizer, and they can be used to power sun lamps. By the way, here’s an idea that will make your head spin: According to The Omnivore’s Dilemma: “Unless you grew up on organic food, most of the kilo or so of nitrogen in your body was fixed by the Haber-Bosch process.” The Haber-Bosch process is the method used to make ammonium nitrate fertilizer out of petroleum. Nitrogen is one of the body’s basic but essential building blocks, like carbon. So, this means if you are the average American, approximately one percent or two pounds of your body weight is literally composed of petroleum by-products.

Running out of food is just one example of how the population bomb may explode. Further below, I will talk about how we can extrapolate any consumable or non-renewable resource, like the air we breathe. But first, how long do we have left?

How often do mass extinctions occur?

The chart below is from Wikipedia, and it shows the frequency of mass extinctions for the last 542 million years. It is easy to see that they occur in regular intervals of about every 64 million years. The last big extinction event, the one that wiped out the dinosaurs, happened 66 million years ago. In other words, we are 2 million years overdue.

Update: Since I originally wrote this article, the scientific community has reached a consensus that we are in the midst of the 6th mass extinction,n called the Holocene extinction. This 6th great mass extinction is being caused by humanity itself.

A proxy measure of oxygen consumption

This graph not only represents population growth but also humanity’s increased consumption or appetite for everything. For example, imagine this graph measures the oxygen consumption of the human race.

Now, imagine every person in the modern world emitting six metric tons of greenhouse gases and pollution. Now double that number (and the amplitude of this graph) to account for all the oxygen used in the combustion process (half turns into water). Furthermore, because oxygen is used in every aspect of life, not just burning fuel, but also in the manufacturing process (especially chemicals and plastics) and the destruction of all those products through oxidation (rotting, burning, rusting), triple the amplitude yet again and this represents a conservative estimate of the oxygen consumption of the human species.