What is it about?
Overpopulation threatens massive suffering for billions of people and extinction for millions of species. These facts justify efforts to reduce human numbers as quickly as humanely possible, as a matter of justice between current and future generations, and between humans and other species. Such efforts should start not someday, somewhere else, but here and now, in your society and mine. Addressing population is only part of creating just and sustainable societies, but it is a necessary part. While taking up population matters is contentious and challenging, continuing to ignore them is likely to go much worse.
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Why is it important?
Environmentalists today are largely silent regarding overpopulation. They rarely weigh in on national population policies, leaving that to corporate lobbyists and pro-growth economists. But environmental sustainability cannot be achieved in a context of unprecedented human numbers and continued population growth. The evidence is clear. Humanity is cooking the Earth, bathing it in a toxic brew of plastics and chemicals, and extinguishing many of its species. None of these global environmental trends are improving; instead, they are merging into a single calamity imperiling the entire living world, including us. During the past decade, many scientists have concluded that addressing population must be part of global industrial civilization reforming itself sufficiently to avoid ecological disaster. A recent “Warning of a Climate Emergency,” signed by over 11,000 scientists, forthrightly states: “the world population must be stabilized — and, ideally, gradually reduced — within a framework that ensures social integrity.” It turns out a lot rides on talking honestly about population matters.
Perspectives
I first became a committed environmentalist forty years ago, as a young man fighting a new dam proposed for the Oconee River in Georgia. Readng the EIS for that project was my first time seeing US Census Bureau population projections, in that case being used to justify construction of the dam. Since then, I have seen recent and projected population growth used to justify numerous environmentally harmful projects. And conversely, I have seen and read about numerous places where population decrease has facilitated ecological restoration and the return of rare and endangered species. Fewer people is the environmental gift that keeps on giving. Environmentalists need to face the fact that we will never create sustainable societies without ending and then reversing human population growth. The alternative is to accept a permanently sterilized and depauperate world.
Philip Cafaro
Colorado State University
Read the Original
This page is a summary of: Too Many People: Applying IPAT in an Overpopulated World, December 2025, De Gruyter,
DOI: 10.1163/9789004746404_013.
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