Urban Sprawl. Photo by

A lesson from the COVID-19 pandemic on the perils of density

Guest Post by Philip Cafaro, Professor in the Department of Philosophy and Affiliate Faculty at the School of Global Environmental Sustainability

In recent years, some environmentalists have argued that increasing population density is the key to creating sustainable societies. COVID-19 suggests they are mistaken. When increasing density becomes a substitute for setting limits to human numbers and demands on nature, environmental conditions deteriorate. And as usual, poor people and other species wind up paying the price.

The current global pandemic, devastating as it is, has the potential to teach people some useful environmental lessons. One is that commercializing wild animals and selling them in unhygienic “wet markets” is an invitation to epidemiological disaster. Another is that no matter how out of fashion national borders have become in certain quarters, they can still play a useful role in protecting public health and well-being. Still another is that the current global economy is toxic: with this novel coronavirus drastically ratcheting back economic activity, fish are being spotted in Venice’s canals, New Delhi residents are breathing easier and can once again see the Himalayas, and Los Angeles’ smog has disappeared.

Perhaps the most important environmental lesson COVID-19 can teach environmentalists is that increasing the density of human populations is not the answer to our environmental problems. Even in normal times, excessive density harms people’s physical and mental health. During a pandemic, density can quickly turn deadly.

It’s no accident that COVID-19 was birthed in Wuhan, a crowded megacity that has grown from 2½ million to 11 million people since 1980. COVID-19 passes from person to person via droplets when someone talks, sneezes, or coughs. Like many epidemic diseases, it scales up more quickly the more densely people are packed together and the larger the pool of potential targets. Crowding in Wuhan provided the perfect setting to incubate the disease. Chinese officials’ slipshod response combined with extensive air travel to do the rest, spreading the disease around the world.

It’s no accident that Italy, one of the most densely populated nations in Europe, has been the continent’s hardest hit country. Nor is it a coincidence that New York City, my hometown, has been the center of the outbreak in the United States. New York is by far the most densely populated U.S. city (see figure) and the New York metropolitan area is the country’s largest. Efforts to sustain “social distancing” there have been hampered by crowded stores, sidewalks and subways, crowded public housing, even crowded hospitals. New York has done a lot of things right during this epidemic, but that hasn’t kept it from sustaining 28% of America’s COVID-19 fatalities to date, with less than 3% of its population.

Figure from Wendell Cox, “Early observations on the Pandemic and Population Density,” newgeography.com, 4/5/20.

So far, density has proven to be deadly with this novel coronavirus, and that is likely to remain the case as it ramps up in large cities around the world. Stories from France to India to Brazil have detailed how difficult it is for people in crowded cities to practice safe social distancing. For poor slum dwellers, living packed in one or two rooms and sharing communal water sources and toilets, it is literally impossible. They will simply have to take what’s coming and hope for the best, as usual.

Meanwhile—again as usual—rich people are finding ways to insulate themselves from the problems of their fellow citizens. In Paris and New York, many wealthy residents have decamped to their country homes, spreading disease to new areas and putting pressure on local food and medical resources. Billionaire David Geffen took to his jumbo yacht Rising Sun (price tag $590 million, standard crew of 45) to ride out the epidemic safely in the Caribbean. “Isolated in the Grenadines avoiding the virus,” he wrote on Instagram: “I hope everybody is staying safe.”


In recent years, “smart growth” advocates in the U.S. and Europe have argued that increased density is the key to creating more ecologically sustainable societies. Fill in those unused city lots with more houses and office buildings. Re-zone detached, single-family housing areas to allow apartments. Re-zone areas designated for three or four-story apartments to allow six or eight-story ones. Build in! Build up! Yes in my backyard (YIMBY)! Smart growth will supposedly allow us to continue to grow, creating environmental efficiencies, while leaving land outside designated growth areas to remain for wild nature.

But such an approach is bound to fail. All those people crammed into cities still need resources from the countryside. So, in fact, more city-dwellers does not translate into more land left to nature, but instead to more land developed to grow food and host energy infrastructure, more wetlands filled in and more forests managed intensively—and more second homes built out in the country for those rich enough to afford them. As our cities, towns and populations grow, we inevitably take more resources from other species and gobble up habitat they need to survive.

Urban Sprawl. Photo by from Pexels.

Similarly, density’s touted environmental efficiencies turn out to be less valuable than advertised. It’s true that New Yorkers have some of the lowest per capita greenhouse gas emissions in the United States, due to more mass transit use and apartment living—a function of high density. But the metro area generates the highest total greenhouse gas emissions of any similar area in the country—a function of its excessive population. When YIMBYs urge their fellow Americans to become like NYC and San Francisco and embrace denser development, they really are urging us to increase our overall greenhouse gas emissions. As a consolation prize, we will get to virtue signal that our per capita emissions have gone down. But it is total emissions that ultimately matter when it comes to climate disruption.

In the same way, from an environmental perspective, what matters is total water consumption, total demand for food, total land paved over in concrete, total air miles flown. More people mean more of all these environmental stressors. That’s the bottom line. Living in a dense urban area may decrease your personal contributions to air pollution, but if your child has asthma, it increases the chance that she will wind up in the hospital. The current pandemic is likely to disproportionally take the lives of many urban residents with respiratory problems. For these people, “smart growth” is a cruel joke.

None of this argues against sensible zoning, alternating more dense with less dense areas. Nor does it mean that good city planning is not an important part of an effective environmentalism. But increased density should not become an end in itself, or a substitute for setting limits to human demands on nature. It should not become an excuse for more population growth in places like California that are already groaning under excessive human numbers. Then “smart growth” becomes a way for clever people to continue to do dumb things; a rebranding of conventional real estate development as cutting-edge environmentalism.

Smart growth, the new urbanism, “yes in my back yard.” If these efforts are not combined with a commitment to limiting human numbers and demands on nature, they become mere bait and switch tactics to hide the fact that environmental damage continues to worsen under the economic and demographic status quo. That’s the path humanity treads today, as climate disruption, ocean acidification, mass species extinction, and other ecological degradations threaten the entire planet. The evidence clearly shows that this path is unsustainable. And even if increased density was sustainable, physically, we would need to ask: is it a path we want to take?


Living cut off from the natural world, surrounded on all sides by humanity and humanity’s works, isn’t just unhealthy: it’s bad for the soul. This past weekend, I took a break from “sheltering in place” and spent the day hiking in the foothills near the town in which I live and work. I didn’t see anything out of the ordinary. Just the usual pines and firs on the uplands and willows in the draws; the usual Steller’s jays and gray jays, white-breasted and red-breasted nuthatches, robins and ravens; the usual blue sky and white clouds. But it did me a world of good to stretch my legs and see spring coming in, in a hundred little ways. The swelling buds on the willows. The robins scuffling for territory. The mountain bluebirds, vivid, crisscrossing the meadows.

Lady Moon Trail, Roosevelt National Forest, Colorado. Photo Courtesy Philip Cafaro

My family and I are blessed to live in a place where we can access natural areas quickly and easily, and where we don’t have to fight crowds once we get there. The wild plants and animals are lucky, too, that people with foresight protected their habitat, setting aside these areas from intensive human development. I’m convinced that human beings need such places to remain human, to connect to parts of our souls and our history that make us who we are. Is it just coincidence that in thousands of cultures, from the ancient Jews to contemporary Native Americans, men and women have sought religious inspiration in wild places? These intellectual and spiritual “resources” should be available to everyone, and not just today but in perpetuity. It is a terrible sort of poverty to be cut off from nature.

It’s only very recently, within a few generations, that people have created great megacities like Wuhan, New York, New Delhi, or Tokyo, with many millions of inhabitants. Places where we cannot see the stars and the nearest uncrowded area is hours away. It isn’t clear yet that we can live in such places without going crazy. The experiment needs to be run awhile longer, and we would be wise to keep small, less dense “controls” in place, in case the outcome is negative.

What is clear is that wealthy folks who have every opportunity to cushion the strains of urban living typically escape it regularly, to second homes and on fancy vacations. And when the next pandemic comes, you are likely to find that the planners and politicians who said “yes in my backyard” to increased density have another backyard in a less populous part of the world, to which they can safely retire. “Isolated at my place in the Hamptons,” they will say, or “at Lake Tahoe,” or “in Malibu.” “I hope everybody is staying safe.”

High density is not the answer to the riddle of ecological sustainability. It brings increased damage and added problems, rather than real solutions. The answer, instead, lies in limiting our numbers and our consumption, so that we can share the Earth generously with other species and with each other. Let’s not be dense! Let’s learn from this terrible pandemic and start to make the changes we need to create a better future.

The author communing with nature. Roosevelt National Forest, Colorado. Photo Courtesy Philip Cafaro.

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