The Overpopulation Project
TOP – Research and Outreach
Too many people consuming too much
Category: Population growth
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The role of mortality in fertility transition studies
Many of those concerned about overpopulation are encouraged by trends showing declining births per woman (TFR). However, a recent study by Skirbekk and Spoorenberg shows that taking declining death rates into account, net reproduction and hence the population growth rate have peaked later than typically reported. Most striking, in seven African countries, fertility transitions have…
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Housing affordability improves when population growth eases
Whether immigration fuels the housing crisis is hotly debated. Recent wide fluctuations in population growth have provided a natural experiment. The data are in: slowing population growth makes housing more affordable. by Jane O’Sullivan In the past two decades, many high-income countries have endured unprecedented increases in the cost of homes to buy or rent.…
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Is Legal Abortion Required for Sustainable Fertility?
Our planet can’t sustain an ever-growing number of humans, but many countries have already reached below-replacement birth rates enabling a future rebalancing of humans with nature. While modern contraceptive technologies deservedly take most of the credit, how important has abortion access been? by Richard Grossman, MD, MPH All readers should be aware that globally, humans…
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Watershed Woes
Despite half a century of efforts to improve water quality and restore fisheries in America’s Chesapeake Bay, its ecological condition continues to decline. A new study quantifies the environmental problems within the Chesapeake Bay watershed, explores their causes, and discusses possible futures. by Philip Cafaro As the third largest estuary on Earth, the Chesapeake Bay…
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What Are Floors Without Ceilings?
Staying within safe planetary boundaries for global resource use and pollution makes good sense. Are there a complementary set of economic and social measures that could help human societies remain within ecological limits? by Erik Assadourian Not long ago a new update to the Planetary Doughnut was published in Nature, complete with 35 indicators to…
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Housing Costs a Matter of Supply and Demand
The Trump administration’s favors to big business threaten America’s environment. But its immigration crackdown has sparked welcome debates about the costs and benefits of continued growth, including its impact on affordable housing. by Henry Barbaro and Philip Cafaro Last month, U.S. Vice President J.D. Vance argued that a surge in illegal immigration has pushed housing…
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Why is Africa’s extreme population growth ignored, despite very serious consequences? And how will Europe respond?
Continued rapid global population growth is unsustainable, but the media instead focus on low birth rates in developed countries. Most future growth will be in Africa, where young people want to emigrate to Europe or other developed regions. How will EU countries act in the face of Africa’s extreme population growth and increasing migration? By…
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Thank you for the Baklava
Through a story centered around the nurturing of an orphaned owl, author Carl Safina tackles topics such as biodiversity loss, human overpopulation, and human beliefs. Richard Grossman has read the book. by Richard Grossman MD “Alfie & Me” is a many-layered joy to read! Its main story is as delicious as they come. An orphaned…
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It’s not racist to say: we are full
Should migrants be “blamed” for rising house prices? Or should we set aside blame and acknowledge that population growth, whatever the source, has some negative impacts? by Gaia Baracetti I recently had the good fortune of visiting Vancouver, a city where I used to live a long time ago. While still beautiful, it appeared to me…
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Farewell to Jane Goodall — Population Activist
Jane Goodall was a champion for chimpanzees, conservation, and population activism. The latter aspect of her work has been conspicuously neglected in recent tributes to this scientific giant. by Leon Kolankiewicz Pioneering English primatologist Dr. Jane Goodall (1934-2025) passed away last week at the age of 91. In the days since, numerous, well-deserved and glowing…
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Population stability could improve UK living standards
With a population nearing 70 million, the UK is feeling the pressure on the housing and job markets. Stabilising the population would ease this pressure, giving more people access to affordable housing and strengthening wages, utlimately raising the quality of life for UK citizens. by R. M. Smilie Introduction The United Kingdom (UK) has rarely…
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Fears that falling birth rates in US could lead to population collapse are based on faulty assumptions
Pronatalistic alarmism about an oncoming economic crisis driven by a decline in birth rates is largely unfounded. In reality, the average number of children per woman in the US has stayed relatively consistent in recent decades, and technological advancements and increased workforce participation mean that the proportion of workers can remain stable at lower fertility…
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Degrowth
Degrowth is a relatively new word, and although there are different interpretations, one thing seems certain: sustainability cannot be reached without embracing degrowth. by Richard Grossman MD Recently I wrote about 2 words that have negative implications to many people, “population” and “overpopulation”. I’m now introducing a word that will be new to many people…
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Thirsty for Growth: How Arizona is Trading Water for Sprawl
Touted as a conservation success story, new legislation in Arizona is actually a ploy to resume unsustainable development in areas that are running out of water. It foolishly seeks to override hard physical limits with paper water credits, displacing wildlife and farmland in service to sprawl. by Phil Cafaro In June 2025, the Arizona Department…
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Growth Addiction and Water in the American Southwest
GrowthBusters is a terrific podcast dealing with the environmental costs of growth, hosted by Dave and Stephanie Gardner. On their latest episode, river activist Gary Wockner talks about the state of the Colorado River and the growth obsession that keeps cities and states in the southwestern U.S. from responding rationally to increasing water scarcity. by…
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For the sake of food security, we must address population numbers
On World Population Day, Jenny Goldie reminds us that food is humanity’s most basic and most vulnerable necessity, but reducing the number of mouths to feed remains off the food security agenda. by Jenny Goldie As a child, the thought of other children going to bed hungry upset me. Later, I began university studies in…
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The Demographic Struggle Over International Migration
A large percentage of people want to emigrate to another country, but many people in destination countries are opposed to accepting large numbers of immigrants. International migration is a highly difficult issue with no simple solution. by Joseph Chamie Approximately 1.3 billion people, or 16% of the world’s population, wish to leave their country permanently,…
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The Carl Wahren papers are now available at Sweden’s National Archives
The Overpopulation Project has been ranked as one of the 10 best demography blogs of 2025 by FeedSpot. Thank you to all our readers for engaging with and sharing our work. For researchers working on historical population issues and interested lay persons, the Carl Wahren papers are a gold mine. See examples below, described by…
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The imminence (or otherwise) of depopulation
Whether you see a peak and decline of world population as a good thing or a bad thing, lots of people are speculating that it is imminent. Can we believe them? Jane O’Sullivan According to the most recent United Nations projections, the world population will peak sixty years from now at around 10.3 billion. Lately,…
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The Planet Cannot Hold the Weight of 8.2 billion Narratives. Here’s Why…
As ecosystems deteriorate and wealth inequality deepens, the impact of overpopulation on the natural world is well-documented—but its effects on democracy, social cohesion, and psychological well-being remain largely unexplored. This essay examines how our bloated, hyper-complex societies have outgrown their ability to meet individual needs, leading to a breakdown in political and social structures. By…
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Toward sustainable economies
Creating economies that do not devastate the natural world on which they depend is the economic challenge of the 21st century. An intriguing new book from Theodore Lianos explores different answers regarding what that might look like. by Anastasia Pseiridis Capitalism has fuelled unprecedented economic growth over the last three centuries. The emblematic phrase ‘grow…
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A new definition of global overpopulation, explained and applied
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…
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To grow or not to grow
All around the world, politicians, business leaders, academics and many members of the general public worship at the shrine of ‘growth’. They are profoundly and dangerously wrong. by Sandy Irvine, eco-activist from England To grow or not to grow is the really big issue of our times. Most problems boil down to excess growth –…
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America’s “Serengeti” at risk: Population-driven sprawl threatens the Greater Yellowstone Ecosystem
From the Everglades to the Arctic plains, population growth and associated development threaten America’s protected areas. A recent study from NumbersUSA, Greater Yellowstone: An Ecosystem at Risk, documents this for the United States’ flagship national park. By Leon Kolankiewicz and Rob Harding Rampant development and a surging human population are imperiling what has been dubbed…
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“America Needs More People”
That’s according to the editorial board of the New York Times, arguing for expanding immigration into the United States. Based on comments, most of their subscribers disagree. by Philip Cafaro By insisting that enforcing immigration limits is immoral, liberals in the U.S. have twice helped elect Donald Trump President. Facing a second Trump administration, some…
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Reflections on the 2024 Nobel prize in economic sciences: What is prosperity and how did it come about?
How did modern prosperity come about, and why did it happen in some countries much more than others? The winners of the 2024 Nobel prize in economics argue social institutions play a vital role. But what about demography, science and nature? By Frank Götmark Recently, the ‘Sveriges Riksbank’ Prize in Economic Sciences in Memory of…
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Joseph Speidel on Carl Wahren and the early days of family planning
Recent years have seen a concerted effort to rewrite post-war family planning efforts as one big racist, sexist, imperialist conspiracy. It is now important, as the last people who worked on these campaigns pass from the scene, to reflect honestly yet fairly on their work. Here Céline Delacroix, a senior fellow with the Population Institute,…
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No sustainable paradigm is attainable without gradual population reduction
The Jus Semper Global Alliance is dedicated to building a better world based on democracy, sustainability and fairly sharing the world’s wealth. Its website gathers valuable material on a full range of issues regarding economic, social and ecological justice. As its founder and executive director reminds us here, “no matter how efficient and fair the…
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Trump or Harris: the implications for U.S. immigration policy
Who would you choose if you could vote in the upcoming U.S. presidential election? Who Americans choose has important implications for people around the world. Unfortunately, neither major party candidate is committed to ending U.S. population growth or creating an environmentally sustainable society. by Philip Cafaro Once every four years, I attend to my civic…
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‘Climate refugees’ and the question of limiting immigration: a response to Migration in Hotter Times
A recent discussion paper on climate refugees, Migration in Hotter Times: Humanity at Risk, does much to muddy the water without presenting practical solutions. by Jane O’Sullivan and Philip Cafaro Immigration is a deeply divisive topic, even among population activists. It is not uncommon to have a strong commitment to global population stabilisation while believing…
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Losing Our Minds
In the 1970’s the leading intellectuals in the United States were concerned about overpopulation. Fifty years later, the best and brightest minds in America now think we are running out of people. What the hell is going on? by Brad Meiklejohn “Growth for the sake of growth is the ideology of the cancer cell.” –…
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New US population projection tool under construction
TOP is developing a new population projection tool for the United States, based on US Census Bureau methodology and data. Check it out! You can run your own US population projections under different fertility and immigration scenarios — and help us improve the projection tool with your suggestions. by Philip Cafaro One of our more…
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Songs about population and the environment – what’s your favorite?
Music is a rich source of inspiration for those of us who want to end population growth and improve environmental conditions. TOP looks at some classic hits and new songs recently sent to us and asks for more. By The Overpopulation Project A few weeks ago, two readers contacted us regarding their own songs. Kelvin…
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Green parties lose big in EU parliamentary elections by ignoring the relationship between immigration and environmental damage
Green and left-wing parties lost ground in recent elections to the European Union Parliament, in part by neglecting and even denying the relationship between population growth by immigration and environmental stress. They could have used the topic to their advantage, but failed to do so. Instead it became the flagship issue of the right. By…
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Time to vote!
Immigration is proving to be a hot topic in the run up to EU parliamentary elections. While the focus has been on immigration’s cultural and social effects, changes in immigration policy could also impact future population numbers across Europe. This has consequences for citizens, the environment and ecosystems. by Philip Cafaro According to the European…
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Meet the Nigerian Teacher Who Advocates for Family Planning
Coming from a family of seven children, Chidera Benoit knows better than anyone how challenging it is to grow up in a big family in Nigeria and achieve a good living standard. Convinced that Nigerian women and men should be free to decide their family size, this young and motivated teacher and Executive Director of…
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Overpopulation Is Still a Huge Problem: An Interview with Jane O’Sullivan
Despite reports that world population is peaking and fertility rates dropping, the human population is still growing at an unrelenting and unsustainable pace. In an interview by Richard Heinberg, Jane O’Sullivan sets the record straight. By Richard Heinberg, originally published by Resilience.org In February, I interviewed biochemist Chris Bystroff, whose peer-reviewed analysis suggests that world…
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Recent blog posts
- A useful tool to explore future population possibilities
- The role of mortality in fertility transition studies
- Population growth is still rapid. Has the UN Population Fund (UNFPA) forgotten family planning programs?
- The Most Appropriate Response to Falling Birthrates? Embrace Them
- New paper defends a pragmatic definition of overpopulation
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