You may already have heard of the Voluntary Human Extinction movement (acronym: VHEMT). Human extinction? Yes, they’re serious — I think. It sounds like a totally fringe and bizarre cult, but it’s not. It’s not about suicide, or even involuntary population reductions such as war, famine and disease. It’s about not having children — their slogan is “may we live long and die out.” To support the movement, you don’t have to actually endorse or believe in human extinction, you just need to stop reproducing. The basic argument is that humans have so totally corrupted the planet that the only way we can restore the natural balance is through our own extinction. (And no, you don’t have to give up sex, unless you want to.) Their arguments are so calm and reasonable, that it makes you wonder that maybe they’re on to something.
As you might guess, I’m a bit uncomfortable with the idea of human extinction. It sounds so, you know, ominous and doom-like, especially when it refers to us. I thought human extinction was what we were trying to avoid! Haven’t humans achieved a vast quantity of knowledge, beauty, and wisdom, and wouldn’t this be irretrievably lost? Why shouldn’t we just reduce human population to a more sustainable and ethical level?
But there are two things I like about VHEMT. First, that it’s nice when some radical people start putting forward ideas that are so far out in left (or right?) field that it makes your own radical ideas look downright middle of the road. But second, I actually agree with 90% of what they say.
My best guess is that the optimum human population is about 10% of our current population, on the order of perhaps a bit over half a billion or so (compared to current 7.3 billion and growing!). That sounds pretty radical; I’m advocating reducing the human population by 90%.
But this would hardly be human extinction or anything even close. To give you an idea of how far this is from “human extinction,” consider this: a 90% reduction in the population of the world would take us back to what it was before 1700, roughly half a billion. And agriculture, the most wildly successful technological innovation of all time, had already expanded human population over 100 times since its inception about 10,000 years ago.
Why do I believe that the optimum human population should be at pre-industrial levels? First of all, I’m not committing to a precise recommendation. David Pimentel, noted emeritus professor of ecology and evolutionary biology at Cornell, has suggested a population of 2–3 billion, a reduction of about two-thirds from the current population level. Some deep ecologists want to go back to hunting and gathering, which means an even lower population, and a reduction in current population levels of over 99.9% if it is to be sustainable. At the dawn of agriculture, human population was only about three million. These suggestions of “optimum human population” are all highly debatable figures and I’m happy to discuss this further and perhaps change my mind.
We have really stretched agriculture to the limit, and today the only reason that our food supply isn’t already inadequate is the continual extension of the Green Revolution. But the Green Revolution is heavily dependent not just on technology, but on resources, like water and fossil fuels, and those resources are already maxed out or actually depleting. The Colorado river is already 100% utilized (mostly by agriculture) and is dry by the time it reaches the Pacific Ocean. And we all know that fossil fuels are depleting. Vaclav Smil, a scientist and policy analyst, thinks that without artificial fertilizers (synthesized from natural gas, a fossil fuel) 40% of the world’s population would not be here.
But the primary long-term limit on human population is the soil. According to Pimentel again, we are eroding soil 10 times faster than the natural rate of soil formation. (And it’s even worse than this in China and India.) If we are truly going to be in balance with nature, we would have to keep most current agricultural land out of production. If we had 90–95% of all agricultural land as fallow land, that would allow the land to recover.
So it’s not sufficient just to say, “oh, no problem, we’ll just go vegan.” Currently, about half of all cropland is going for livestock agriculture, so potentially worldwide veganism roughly doubles the amount of cropland that can be used for humans. Fine, that allows a population of 15 billion! But, we need to keep 90–95% of all land fallow. Oops, that reduces the people that we can support by 90–95% (or to 0.75 — 1.5 billion). We can also figure in various other things like the end of fossil fuels, depleting groundwater, the bankruptcy of the Green Revolution, and the political and social difficulty of implementing agricultural reforms. For practical purposes we are looking at an optimum level of human population in the ballpark of human numbers prior to the industrial revolution.
That sounds like a pretty ominous reduction. But thanks to VHEMT, I can give this a positive spin. It is possible for literally hundreds of millions of humans to live sustainably on the planet, at population levels over a 100 times greater than our “natural” population levels (those prior to the development of agriculture, about 3 million). Thank you, modern technology; and thank you, VHEMT, for making this view (by contrast) look so reasonable.