Scientists Say Earth Needs to Shrink by Billions of People By 2200. But I Think We’re Already Screwed.

4 min readHere’s what you’ll learn when you read this story:Recent studies suggest that the overconsumption of fossil fuels over the past century has hidden the costs of overpopulation on the planet. The results of this mismatch could lead to food insecurity and an uncertain future unless we reduce Earth’s population by billions of people by 2200. Shrinking the population would slow climate change, but that takes centuries, so we have to invest in sustainable tech and brace for scarcity.The crisis of overpopulation has been debated for nearly 250 years. In 1798, English economist Thomas Robert Malthus’ An Essay on the Principle of Population outlined an idea later dubbed the “Malthusian catastrophe” where population growth outpaces agricultural production. In 1968, these longstanding concerns bloomed into full-blown overpopulation fears following the publication of The Population Bomb by Paul and Anne Erlich. Just five years later, when Earth’s population was only 3.9 billion, the movie Soylent Green depicted a world that essentially collapsed under the collective weight of humanity.Fast-forward half a century, and food is thankfully not yet made of people, but the crisis of an ever-growing population remains.In a study recently published in the journal Environmental Research Letters, scientists pored over two centuries’ worth of historical population records and ecological growth models to see whether the planet could keep up. They concluded that while humanity’s resource output kept pace with population increases for generations—largely driven by innovation, technological advancement, and increased efficiency—the tables started to turn in the early 1960s, not long before the publication of The Population Bomb. Around that time, the human population continued skyrocketing, but ecological resources began to shrink.The result? For nearly 60 years, humanity has been writing a check that neither it—nor the planet—can cash. More humans means more resources, energy, and food, and in much of the industrialized world, overconsumption and unending growth lie at the foundation of the entire economy. The situation is so dire that the Intergovernmental Panel on Climate Change (IPCC) even lists population growth as a key driver of greenhouse gas emissions.So, yeah. We’re screwed.“Earth cannot keep up with the way in which we are using resources,” Flinders University’s Corey Bradshaw, lead author of the study, said in a press statement. “It cannot support even today’s demand without major changes, with our findings showing that we are pushing the planet harder than it can possibly cope.”But how has our population been able to grow beyond a size that our host planet can really support? One big reason is that finite fossil fuels can temporarily hide the effects of ecological overshoot. In other words, continuing to support a growing economy as well as a growing population just doesn’t math out in the long run—or even in the here and now.“Today’s economies predicated on uninterrupted growth apparently do not recognize the regenerative constraints of sustained population expansion, because fossil fuels artificially make up the differences,” the authors wrote. “Nor do economies anticipate the looming reductions in regenerative capacity as climate disruptions intensify.”I wanted to think about what life would actually look like under these ecological constraints—and I didn’t have to think very hard.In some instances, we’re already living through that scenario. As the World Economic Forum highlights, the first inklings of a looming crisis doesn’t arrive in the form of immediate food shortages, but rather through growing pressures on the agricultural system. For example, the increasing cost of artificial fertilizers—perhaps the key innovation that helped humans avoid population limits in the 20th century—could generate cascading price shocks that slowly reduce food yields. Research has shown that overpopulation also fuels pandemics and income disparities, leading to poor quality-of-life outcomes. It’s possible that once they’re pushed to the brink, societies will begin adopting—or even forcing—consumer philosophies such as limitarianism, which places egalitarian limits on the resources one person can consume.Although it’s only taken roughly a century for the world’s population to balloon by more than six billion, up to the current 8.3 billion (by our best estimates), a strategy of depopulation won’t solve the crisis we’re in. Bradshaw and his team predict that the global population could continue to climb up toward 12.4 billion around 2070 before beginning to decline.A study in the journal Sustainable Development advocates for reaching a population of four billion by the year 2200 because more people predictably means more CO2 emissions, energy and freshwater use, mineral extraction, plastics production, and wildlife loss.“Embracing a smaller population may seem discouraging or strange, as we have lived in an era of rapid global population increase,” the authors write. “But the global population quadrupled over the past century, and that is a much more disruptive change than if the population were to shrink by half over the next 170 years.”But humanity doesn’t have 170 years to solve the current ecological crisis. So fighting for a non-soylent future means investing in sustainable technologies, ending our reliance on fossil fuels, and working toward an economy that lives within the bounds of what our planet can provide.Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.