Human Population Growth: The Hidden Factor in Climate Change?

Either we solve it or it will be solved for us

Photo by Hardcore Brain on Unsplash

I am wondering if I have been barking up the wrong tree. Ever since I started writing about climate change several years ago, it seemed evident that we could solve our atmospheric carbon and greenhouse gas problem by shifting to a) non-emitting energy sources, b) electrified tools (ranging from cars to the way we heat our homes), and c) technology to remove carbon from the atmosphere. Today, I’m not so sure.

The shift happened because of a fact I could not fully understand, but which would not leave me alone—that global population grew by over 10X since the start of the Industrial Revolution in 1750. I wondered: Did that matter in some way that I was not seeing? I decided to look more closely.

The global population estimate for 1750 is 750 million. Today, it is 8.03 billion. That is an increase of 10.7 times from 1750 to present day. During that same time, estimated global CO2 emissions went from 9.1 million tons in 1750, to 37.1 billion tons today. That is an increase of 4,078 times since the start of the Industrial Revolution.

At first, I thought the 10X growth in population was dwarfed by the overall increase of 4,078X. But then I did the math.

Global emissions since the Industrial Revolution grew by 4,078 times. During that time, population grew by 10.7 times. If you divide out population growth (4,078/10.7) the factor left is 381. That factor represents the growth in emissions from influences other than population growth. Multiply the carbon emissions in 1750 (9.1 million tons) by that factor of 381, and you get 3.468 billion tons of CO2 emitted into the air. That seems like a lot. But today, our current global emissions are 37.1 billion tons! The difference? That 10.7X growth in human population.

One could guess reasonably enough that the 381X factor has to do with the expanding adoption of fossil fuel technology—i.e., more and more people driving cars and electrifying their homes—and the development of new technologies that require ever more energy—for example, cars replacing horses over a century ago and the more recent developments of AI and cryptocurrency. Perhaps there are other factors, but these two are a big part of the 381X factor. Despite that, without the increasing number of people on the planet to adopt and use fossil fuel driven technology, our emissions would be 90% less than they are today. We would not have climate change.

For me, this was a startling insight. In all the debate on climate change, technology, and an economic system that requires growth and cheap energy, perhaps we are missing a sobering fact—there are just too many people on Earth. We can blame agriculture for fowling the land, industry for raping mountains to get minerals, and industrial fishing for decimating fisheries. We can blame the oil companies for their direct emissions in producing and refining oil, and for their attempt to push fossil fuels onto society. We can focus our ire on consumers who waste too much, people who travel by air, or the carnivores in our midst. But at the end of the day, none of this would matter if the population of humans on Earth had not exploded since 1750. Indeed, the industrialization of fossil fuels, transportation, agriculture, mining, and more extractive industries could not have happened without the demand for those products made by more and more people on Earth. We are not destroying the ecosystems and heating up our planet in service of industry, but rather in service of our wildly expanding population.

It seems then that we have these three levers in the effort to stem climate change—technology creation, technology adoption, and population growth. Theoretically, humans could control all three, but there are virtually no signs we will do so. Technology creation and adoption are too important for meeting the needs of a growing population,  such as food, water, clothing, and shelter. At the same time, population control runs into moral and religious values that millions or billions of people will not violate. Additionally, countries like Denmark, Sweden, Japan, and even China are now putting in place “pro birth” policies which encourage people to have more children because the governments fear what a falling population will mean for their economies. Even in the US, despite the rising tide against immigration, economists understand that immigration increases population and so is actually a pro-growth phenomenon. As it turns out, it is hard to grow an economy without a growing population.

So, where does that leave us? It leaves us with one rather chilling and difficult answer. If we cannot control emissions because an increasing population adopts more and more fossil fuel driven technology, then nature is likely to balance things out herself. Nature is going to take its course. It cannot control the invention of technology, and it cannot limit the diffusion and adoption of technology in human society. Hence, it has but one option. Nature’s course will be, in some guise or another, a substantial reduction in the human population. This could be through a direct effect such as with heat waves, storms, droughts, and other “natural” events, or it could be through derivative effects, such as wars over the scarce resources we need—food, water, shelter, etc.

Whether direct or indirect, it seems that nature’s process has already begun. We see it in the growing fury of natural events and we see it in the incremental changes in the biosphere. Species extinction is one thing, but the changes in climate that mean coffee areas can no longer grow coffee, wine areas can no longer grow grapes, and grains areas can no longer grow grains—all of which are happening—create the crisis over resources that will define our future. These changes will create desperate populations struggling to survive and increase the likelihood of famine and war.

What I am concluding is stark. There seems to be no way to solve climate change but with a radical reduction in the population. Because no one wants to volunteer to be among the reduced, we are effectively handing the work over to nature. In a way, humanity is just waiting for nature to do what it must to rebalance the earth.

Although this conclusion is troubling, I am not saying that the work we do to handle climate change is for naught—far from it. Indeed, every little thing we do to limit or correct emissions will both delay and reduce the size of the catastrophe that seems inevitable. We need more conservation, not less. We need more and better green technology, not less. And we need more of that technology deployed, not less. And, if we could put together policies that could humanely reduce population while we do all those things, we could hold off climate change impacts while simultaneously relieving pressure on all the various forms of extraction of resources that drive the capitalist economy. Climate change could be solved and the biosphere could be healed. But we can’t do it without a smaller human population on the planet. One way or another, the Earth seems on track to reduce population. We are better off as its partner than its victim.

Anthony Signorelli