Earth Is Running Out of Space

7.7 Billion. That’s the estimated number of people in the world today. To put it in perspective, that’s one hundred and ten thousand NFL stadiums filled to capacity. If each of us were to hold hands, we would surround the entire circumference of the earth 345 times. The concept of billion is difficult for us to wrap our heads around, especially when it comes to people. Think about it. How many people do you interact with on a regular basis? 

You’ve got your partner or your roommates you split the rent with. Your parents, your siblings, your group of friends. Your work colleagues you chat with over Zoom or at the office and the barista at the coffee shop you stop by every morning. It‘s not a ton of people, right? At times, our lives can feel like they’re carried out entirely within our own personal bubble. We go about our daily routine inside its confines, traveling within the perimeter and making contact only with the select few whose bubbles overlap with ours. But in truth, each and every one of us belongs to the far vaster, endlessly entangled network that is the human race. 

Right now there are over 7.7 billion people living on Earth. And that number is growing. Every single day around 385,000 babies are born. On the opposite end of life, only around 166,000 people die every day. Which means on average, our population grows by around 219,000 per day. That is astronomical. 

Humans lived on Earth for hundreds of thousands of years before our population reached one billion people in the year 1804. But after that, it only took us another 200 years for the population to expand by seven times that size. If we continue to grow at this pace, there will be around 8.5 billion people on the planet by 2030, 9.7 billion by 2050, and just under 11 billion by the year 2100. 

Even with saying these numbers out loud, it’s still difficult to fathom just how many humans 11 billion is. Couple this with the fact that as an individual you are unlikely to feel the direct effects of population growth as you go on about your everyday life, and it’s no wonder that this is not seen as a big of a problem as it truly is. The sad reality of our rapid population growth is that the  people who inhabit the planet, the more resources, clean air, fresh water, food and shelter we will need. So, how many humans can our planet realistically support? Can that number continue to grow indefinitely, even though our resources are finite? How big can the human race get before the earth can no longer sustain us? 

The answers aren’t so simple. But whenever scientists contemplate this towering existential question, they break it down using a concept called carrying capacity. Carrying capacity is meant to determine the maximum amount of people the Earth can support before the population will reach its peak and naturally become forced to, well, course correct. So what will it look like when we’ve maxed out the number of inhabitants the Earth can comfortably carry? It’s not a pretty picture, but it’s probably nothing you haven’t heard already. 

As our population continues to grow, almost all scientists anticipate we’re going to experience some problems. We’ll inevitably face a shortage of fresh water and farmable land, which will only be further aggravated by climate change. And the average human lifespan, which rose from about 65 years in the early 1990s to just under 73 years heading into the 2020s, could begin to decline once more as a result of disease and starvation. Basically, this means that if the global population continues to accelerate without any limitations, then the quality of life is likely to decline for vast amounts of people on Earth. 

For anyone who is fully aware of the colossal obstacles looming over the human race in the future, it can transform a fundamental life decision – such as the decision to have children – into an immense ethical dilemma. Is it ethical, you might ask, to bring children into a world where global warming and overpopulation could make the quality of their lives significantly worse than your own? 

But it’s not just your future child’s quality of life that you have to contemplate as you’re grappling with this moral quandary. It’s also the fact that, purely by having children, you may be inadvertently putting more strain on a world that doesn’t have the capacity for it. A 2017 study in Environmental Research Letters found that there were four major lifestyle choices an individual living in a high-income country could make in order to reduce their carbon footprint. These choices were: 1) Switch to a plant-based diet, 2) Quit driving and get around without a car, 3) Avoid flying and 4) Have one fewer child. From this you can see how much energy we could potentially save by having just one less human. 

But there’s a key phrase in that study that I need to call attention to. It was designed for individuals living in high-income countries. You see, carrying capacity and carbon footprints aren’t exact sciences that work the same for everyone across the planet. The amount of carbon emissions you are responsible for actually has everything to do with where and how you live. Part of the way we calculate carrying capacity is by measuring the acres of farmable land needed to support our population.  Worldwatch Institute determined that, if our land and resources were to be evenly distributed and we all became vegetarians, the Earth has just under two hectares (five acres) of land per person. This would theoretically be sufficient to grow food and the material for clothing, supply wood for shelter and absorb waste – all for one person. But today, the average American uses just under 10 hectares (25 acres) of land. That’s well beyond their means if we all want to live equally and sustainably. 

When you start crunching the numbers, well, it becomes impossible to ignore that there are some sizeable disparities in how much of the world’s resources people from certain parts of the world are using. Let’s look at energy consumption, for example. The average Texan consumes double the amount of energy the average American does anywhere else in the country. That’s four times the average UK citizen and eight times as much energy as the average person living in China. The average Nigerian uses half as much electricity for all their needs as just one high-definition TV in an American home uses in an entire year. The same applies to greenhouse gasses. The average Indian citizen emits around two tons of CO2 per year. In the UK, the average annual CO2 emissions per citizen are seven tonnes, while in the U.S. it shoots up to a whopping 200 tons. 

These staggering imbalances mean the question of whether or not to have children can have a huge difference depending on if you’re considering starting a family in Texas compared to Mumbai, India. But I don’t want to reduce big, diverse nations into one-note statistics that don’t really tell the full story. Things are rarely as straightforward as they are made to appear. Even though the wealth disparities between high and low-income countries have clear correlations with the portion of carbon emissions a populace is responsible for, that notion partly disregards the fact that the size of an individual’s carbon footprint is primarily dependent on their personal wealth. An Indian businessperson who hops on their private jet any time they need to get somewhere will produce dramatically more greenhouse gas emissions than an American living below the poverty line. 

The wealthiest 10% of the global population is responsible for 50% of global emissions. The world’s highest polluters don’t all reside in a single country. They live all over the world. Personal wealth, it turns out, has an immeasurably greater impact than national wealth or geographic location. To demonstrate: Jeff Bezos’s 11-minute space journey emitted as much carbon per passenger as the lifetime emissions of the world’s billion poorest people. Let that sink in. 

So, what can we do about this? Should the world’s wealthiest people – those responsible for the vast majority of carbon emissions – just stop having children? Is that even possible? And if we can’t make it happen, is the fate of humanity at risk? 

Let’s look at China’s one-child policy. Between 1980 and 2015, the Chinese government tried to limit its population by only allowing each family to give birth to a single child. And despite the immense and inconceivable suffering it caused, their mission to curb the population worked. After 1980, the overall rate of natural increase in China declined dramatically. After the fact, the Chinese government estimated that they prevented about 400 million births from ever taking place. However, as China’s population now ages, the government is actually urging families to have multiple children. There’s now an age imbalance in the country that needs to be dealt with. By 2050, a third of the Chinese population could be over 60 years old, which would place a lot of strain on state support for the elderly and the adult children who need to care for their aging parents. But if we need to reduce global population growth, could something akin to China’s one-child policy be enforced in other parts of the world? 

Well, it’s sort of starting to happen naturally, even without any formal measures in place. In the 1960s, the global fertility rate was roughly five children per woman. Today, that has organically balanced out to about 2.5 children. And that figure is expected to keep decreasing. You see, for the size of a population to remain constant, parents need to reproduce at a rate that we call the ‘replacement level’. This is roughly two children per couple. 

In some lower-income regions of the world, such as sub-Saharan Africa and Southeast Asia, where there is high child mortality, parents average three to six children. But when you compare that to high-income countries, the contrast is stark. Finland, Japan and the United States have fertility rates that are already below the replacement level. In these nations, smaller families have become the norm. Instead of deterring or even forbidding parents from having more children, a number of these countries have instead  introduced incentives meant to help boost their birth rates, including baby bonuses paid to new parents in Australia, Finland, Italy and Japan. 

In an ideal world, humans would be able to move freely from place to place. We would be able to inhabit whichever part of the planet we want and resources would be shared equally amongst all nations and people. But what we live in is far from an ideal world. Which is why any effort to reduce population might not have as positive of an effect as it might seem on paper. Because the people who use the most energy are a very small percentage of the world’s population. 

So we could remove one billion of the least energy-consuming people in the world and it would still have a smaller effect than simply stopping Jeff Bezos from going on a ride to space.