Some environmentalists believe current environmental problems can be addressed successfully without reducing human numbers, while others disagree. Which side is right? Our new working paper tries to get to the bottom of the matter.
by Philip Cafaro
Recent years have brought a cascade of bad environmental news from around the world: melting glaciers and acidifying oceans; fires of unprecedented size and intensity; unusually numerous and severe tropical storms; record-breaking droughts; dying coral reefs and dying boreal forests; massive bird losses and insect die-offs; and much more. The news is grim and the trends suggest worse to come.
While the details and proximate causes vary, the underlying cause of all this bad news seems clear enough: an immense and rapidly growing human population and its economy, serving huge numbers of two-legged consumers. We are generating so much atmospheric carbon because there are many more of us than there were one hundred years ago, we are on average much wealthier, and we have more powerful technologies at our disposal: the ability to drive cars, fly around the world, grow a lot more food, get fatter, and pour a lot more concrete.
One might object that there are still large wild areas on Earth and that urbanization, with many more people living in big cities, will leave room for wildlife. Yet mammals, birds and insects, frogs and fish, are all in serious decline. We apparently also need their habitats for our own uses – above all farmland for increased food production. Those who argue that technology and improved efficiency “will fix the problem” have much to prove.
As a “World Scientists’ Warning of a Climate Emergency” put it in 2020: “profoundly troubling signs” of ecological degradation include continued human population increase and rapid increases in world gross domestic product. “To secure a sustainable future,” advised the more than 11,000 scientists who signed the warning, “we must change how we live,” enacting “bold and drastic transformations regarding economic and population policies.” The warning explicitly emphasized the need to limit overall human economic activity, not just make it more efficient. In line with the obvious fact that more people generate more economic activity, it admonished that “the world population must be stabilized — and, ideally, gradually reduced — within a framework that ensures social integrity.”
The overwhelmingly bad environmental news, combined with the past hundred year’s population explosion — from two to eight billion human beings — support an argument that the present condition can be referred to as global overpopulation. Yet many environmentalists reject the idea that we need to reduce our populations to achieve sustainable societies. In an effort to get to the bottom of this, TOP now publishes the working paper A New Definition of Global Overpopulation, Explained and Applied. We invite you to read it, to share it, and also tell us what we’ve gotten wrong in the comments below. Go ahead, criticism is valuable and can help us improve the text. If so, we will thank you in the acknowledgements.
*
Judgements regarding population matters, including claims regarding overpopulation, necessarily involve both ethical principles and empirical claims. A useful discussion must make both aspects explicit.
Harming our descendants by degrading essential ecosystem services appears to be an important and preventable evil on any rigorous and defensible approach to ethics. Likewise, extinguishing numerous other species appears to be an important and preventable evil. Stipulating these two ethical principles — it is wrong to seriously degrade future human generations’ necessary ecological support systems, it is wrong to extinguish other species — a working definition of overpopulation follows:
Human societies, or the world as a whole, are overpopulated when their populations are too large to preserve the ecosystem services necessary for future people’s wellbeing and to share the landscape fairly with other species.
In the working paper, we go on to stipulate and defend the following formal definition of global overpopulation. The world is overpopulated if:
- people are degrading essential global ecosystem services in ways that could seriously harm current and future human generations; or
- people are displacing wild animals and plants so thoroughly that we threaten to cause a mass extinction: an event in which a large percentage of Earth’s species are permanently extinguished; and
- (1) or (2) (or both) are being caused, in part, by an unprecedentedly large global human population; and
- avoiding (1) or (2) (or both) would become significantly more likely with a smaller global human population.
Formally this should be understood as if [either (1) or (2)] and (3) and (4), then the world is overpopulated.
We hope this definition is broad enough to appeal to the majority of readers, not just hard-core environmentalists, and that it thus can help people set aside ideology and wishful thinking and honestly answer the question: are we overpopulated? Do you have objections? Please let us know.
This definition does not assume an ability to specify an optimum global human population, or a maximum one. Such efforts are also valuable and interesting, but involve many difficult assumptions. They thus typically end in uncertainty, leaving the sense that the question is unsolvable, absolving people of any responsibility to address population matters.
This definition does not ask for “proof” that any particular population size could never be sustainable, either in theory or given sufficient environmental reforms. After all, we can always imagine deploying magical new technologies, or convincing our fellow citizens to undertake unprecedented feats of temperance and self-control.
Instead, given the severity of the potential harms involved and the difficulty of getting people to reform themselves, our definition claims that if those harms are impending and if lowering our populations would likely help us avoid them, people should consider ourselves overpopulated — and take steps to reduce our numbers.
What those steps should be is a further question, one we will be coming back to at TOP. But the case for action requires a clear definition of overpopulation to begin with. Let us know what you think!
Leave a Reply