Want to Save the Environment? Build More Cities

A new book argues for the environmental advantages of urban density

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Steven Cherry: In a paper published last summer, researchers predicted that “by 2030, urban land cover will nearly [triple] the global urban land area” of the year 2000, resulting in “considerable loss of habitats in key biodiversity hotspots.” A headline in Time magazine last fall said “How Growing Cities Will Wreck the Environment Unless We Build Them Right.”

And in general, it seems obvious that cities are bad for the environment. They’re dirty, noisy concentrators of people and pollution. They suck up natural resources from the countryside and spit back out vast quantities of waste, human and otherwise. What could be less natural than these inland oceans of concrete?

And yet, in what might be the most sustained attempt to question that common wisdom, a new book published last month argues that the weight of our scientific knowledge falls the other way. By and large, cities are environmental pluses, and the more densely populated they are, the more beneficial they are.

With more than half the planet now living in cities, if the common wisdom about cities is wrong, that’s something we need to know.

My guest today, William Meyer, is associate professor of geography at Colgate University, and he’s the author of The Environmental Advantages of Cities, published in March by MIT Press. He joins us by phone. Bill, welcome to the podcast.

William Meyer: Thanks. Thanks for having me.

Steven Cherry: Bill, it’s impossible to prove a negative, but you examine seven areas in which cities are thought to be bad for the environment. We’re not going to have time for them all, but here’s the list of them. Cities are intensive hot spots of ecological disruption, ravenous consumers of natural resources, severely polluted and polluting, particularly at risk from natural hazards, disproportionally beset by technological hazards, inherently prone to the spread of infectious diseases, and such dysfunctional and unnatural environments that they cannot form a satisfactory setting for human life.

Let’s take the first one: Cities are intensive hot spots of ecological disruption, true or false?

William Meyer: Well, it’s true in a way. Cities, which I define as principally densely populated concentrations of human settlement and as areas of predominantly built environment, are the most transformed ecological settings in the world. But the very fact that they’re defined by density means, of course, that you have larger numbers of people occupying a smaller area, so you confine and contain the human impact. If we think about the same population living in a less-urban concentration, you would have much larger areas affected.

Steven Cherry: Yeah, so let’s talk about that for a second. A lot of the arguments in your book kind of depend on looking at these issues in per capita terms, but common sense, that common sense I cited before, also says that cities are people magnets, right? We wouldn’t have as many people except for cities.

William Meyer: Well, in fact, it’s one of the best-established regularities in the social sciences, which, in fact, don’t have many. Urbanization reduces population growth. Yes, it attracts people, but people living in rural areas have higher fertility rates—have more children—than people living in urban areas. So if population growth is the chief threat to ecological sustainability, urbanization is the best answer.

Cities reduce population growth, and they do it in a humane way. They don’t do it by increasing death rates, because, in fact, death rates are higher in rural areas in the world today; life expectancy is higher in cities. They do it in a humane way by reducing fertility, people choosing to have smaller families, fewer children, living in a densely settled urban area. Women’s rights and freedoms tend to be higher in urban areas. People, as the saying goes, shift from quantity to quality in family size. They have smaller families, but they invest more in each child, so the payoff is, again, less population growth and not more.

Steven Cherry: Yeah, you mentioned urban-ness, and I guess we should talk about that for a second. You use a pretty straightforward understanding of the word city, but you also argue that it’s more useful to talk about degrees of urban-ness on a sort of continuum.

William Meyer: Yeah, and I think in a way there’s a lot of confusion that results if you just say, “Here are cities. Here are rural areas. There’s a divide between them.” No area’s entirely urban; no area’s entirely rural. It’s a continuum. So I define cities, and I draw on basically what people use the word to mean in everyday usage: large, sizeable concentrations of people at high densities, with predominance of nonagricultural livelihood, with political institutions from municipal incorporation, and with a predominantly built environment, and, of course, none of those is an either/or.

They all vary, but they sort of vary together, all five of them. And if you look then at a particular area, you can say it’s more urban than this other area, or it’s less, and, of course, then, in the title of the book I use the noun cities. It’s hard not to. But what I mean by cities is areas with a relatively high degree of urban-ness.

Steven Cherry: And we should point out that you take a pretty global view of this, and that’s kind of important because developed world cities differ in some important ways from those in underdeveloped areas.

William Meyer: Sure, and, of course, so do rural areas. And part of the commonsense view that I challenge in the book is that although first world cities may be okay, third world cities are the worst living places in the whole world, that they’re really horror zones. And that’s not consistent with the data on human well-being, on health. It’s also not consistent with the fact that there’s a great deal of rural-to-urban migration in third world cities, and in fact there would be more if governments didn’t try to reduce it or suppress it. So people in developing countries seem to see urban areas as more attractive than rural areas.

Steven Cherry: Good. Let’s go back to the list then. Cities are ravenous consumers of natural resources, true or false?

William Meyer: Okay, well, they are in an absolute sense, yes, and that’s the distinction between absolute and proportional impact. Cities do consume a lot of resources because there are lots of people there consuming, but the question is: If you had the same population, would it consume more resources if it lived in a less-urban settlement pattern? And the answer is no, because per capita, people in cities consume less. Cities are much more efficient in the consumption of resources, notably energy, but also materials, also water, and also, of course, land, because of their higher densities. So it’s true that they are large consumers, but the people who live in them are not, and, again, if we had a less-urban settlement pattern, we’d have more resource consumption.

Steven Cherry: Maybe we could just hit a few of the key points here. One is mass-transit systems, and you also note that apartment living uses less energy than home living.

William Meyer: Well, the living spaces are smaller, for one thing. Heating is more efficient. There’s less loss. They’re better insulated. Yeah, for transportation, obviously mass transit and simply the fact that in very dense cities, people walk to a lot of places. Your origin and your destination, or your home and your work, are likely to be much closer than they are, so there’s much less automobile dependence, and, in fact, it’s much more difficult even to have a car in a city.

Whereas in rural areas, at least in the developed world, it’s almost essential. I mean, it really is essential, and even in suburban areas. Transportation energy is another area. People in cities, as you say, have access to mass transit. They’re much less automobile dependent, and they even walk to a lot of places, especially in very dense cities.

The place they live, their origin and their destination, are usually so close that they can walk, and, in fact, it’s very difficult to even have a car because of problems of parking. So all of these reduce energy per capita use, and I present, I give some maps in the book that show if you map energy use total, then you see, obviously, a big peak in the urban core. If you map energy use per capita, you see a big crater in the urban core, with higher and higher levels as you move outward from it.

Steven Cherry: You point out that in a lot of ways, and I guess this is one of them, that in that distinction between rural and urban, there’s also the suburban, and that’s the worst in many ways.

William Meyer: In many ways, yeah. In some respects, in, I mean, energy use, automobile dependence, rural areas are perhaps even worse because the distances are greater. Suburbs at least have a moderate degree of density, so they’re intermediate in terms of urban-ness. That means they’re intermediate in terms of some forms of environmental impact.

Also, American suburbia is different from other countries, and only America, among developed nations, is a clear suburban majority country. And the levels of population density in American urban areas are very low by world standards, and that translates, of course, into higher, not only energy use, but higher use of other resources, materials, water for watering lawns, and things like that.

I try, as well as defining urban-ness, I also try to define the verb urbanize or to urbanize, and I suggest that what is often called “urbanization” in the United States should really be seen as the opposite, should be called “de-urbanization.” People moving from more- to less-dense settings, becoming less urban, and that’s suburbanization, is basically de-urbanization. And as such it increases resource demands, it increases ecological impact, other problems as well.

Steven Cherry: Let’s continue with the list. Cities are severely polluted and polluting, true or false?

William Meyer: This is probably the closest to at least a half truth of any of the seven, but the usual view, the commonsense view, overlooks a lot of exceptions. One exception, one particularly notable one, is the fact that the world’s worst air pollution anywhere is in rural areas. It’s in rural areas in the third world, and it’s indoor air pollution. It’s because rural areas depend upon smoky biomass fuels, so you get higher levels of that kind of pollution indoors in rural areas. You breathe it in very directly. It’s the biggest contribution to air pollution doses for people, but it’s not visible.

So it’s not visible, first because it’s in rural areas, which get less attention than urban areas do. It’s not visible also because it’s indoors. It’s not visible too because it mostly affects some of the least visible people: women and children in particular. So, I mean, you don’t ordinarily think of rural third world as being the most air-polluted part of the world, but it is.

One of my defining features of urban-ness, as I said, is nonagricultural livelihood, and agriculture exposes people to some of the most toxic chemicals in the contemporary environment, pesticides in particular. And those are obviously a much bigger pollution burden in rural agricultural areas than in urban ones. Cities can provide cleaner water, and they do. Waterborne diseases are less common even in developing countries in urban areas than in rural ones, because cities can protect water sources and provide cleaner water, whereas in rural areas the sources are probably unprotected, and they’re contaminated with human and other waste. And cities in general can clean up pollution simply because they’re concentrated. Again, the density, the concentration, makes it possible to collect, treat pollutants and also, of course, to recycle them. So to turn a pollutant or a waste product into an actually valuable resource, it’s much easier with higher densities, with higher degrees of urban-ness.

Steven Cherry: Yeah, and it turns out you make an argument that’s a little bit like that for infectious diseases as well, right? Cities are indeed prone to their spread, but they also have more resources for fighting disease.

William Meyer: Yeah, so cities have better medical care, but also, more importantly, better public health to prevent the disease in the first place, and that’s especially true for waterborne diseases. Also, too, the built-environment element in how I defined urban-ness, vector-borne diseases, ones that are carried by usually insects—some of the most important of these, in fact, the single most important one, malaria—is much more common in rural areas in the third world, sub-Saharan Africa in particular, because a built setting is less hospitable to the carrier vector organism than a less built, more natural one is. So you think, certainly, a built environment is less beneficial to human well-being, perhaps, but in many ways, it’s safer, so not just malaria but other carrier organisms for diseases.

Steven Cherry: It would seem that almost by definition cities are unnatural and arguably unhealthful to the human soul, but in your book you even question that.

William Meyer: Yeah, I mean, I note for one thing, people don’t say that about agriculture. People don’t have that reaction about agriculture, that it’s unnatural, and yet in the evolutionary history of humankind, one is no older than the other. We’ve had cities about as long as we’ve had agriculture.

Arguably, even cities are more natural because there’s an element of sociality, sociability, in human nature. So density clustering of people is not necessarily unnatural. It may be the isolated life is more unnatural. And if you look at just the history of urbanization and de-urbanization, presumably people would not have clustered into cities, and they would have not migrated to cities if it were somehow antithetical to their deepest nature.

Steven Cherry: Just to close the loop on one of the headlines I cited in the intro, which was how growing cities will wreck the environment unless we build them right. That was from the Time magazine article. It doesn’t seem that we need to build cities in any special way for them to not wreck the environment.

William Meyer: Well, again, it’s a matter of comparing an urban settlement pattern for a given population to the results you would get for the same population with a less-urban settlement pattern. And I think probably the best thing you could do is remove some of the barriers and some of the obstacles that governments, in particular, have created that prevent people from urbanizing. Remove some of the subsidies, especially in developed countries, that have encouraged people to de-urbanize. Those would be the most useful things rather than worrying what cities will do.

The same population living in cities will wreck the environment less than that population would in a more dispersed, spread-out settlement pattern. And that the article that you mentioned at the beginning, published last fall, that I think could be faulted for not comparing the impacts you would get from the same population in a less-urban settlement pattern. All it did was look at the impacts you got from that population living in cities and thereby implied that urbanization in cities is a problem. But that’s only true if it would have less impact living more dispersed, and I think it’s almost certainly the other way around.

Steven Cherry: Yeah, one of the great points you make in the book is that people have to live somewhere.

William Meyer: Indeed.

Steven Cherry: Well, Bill, it’s a fantastically interesting and counterintuitive book, and, you know, I say that, but to us lifelong city dwellers, it’s not very counterintuitive. But to a lot of other people it will be. So thanks for researching it, thanks for writing it, and thanks for joining us today.

William Meyer: My pleasure. Thank you.

Steven Cherry: We’ve been speaking with geography professor William Meyer about his book The Environmental Advantages of Cities, published last month by MIT Press.

For IEEE Spectrum’s “Techwise Conversations,” I’m Steven Cherry.

Photos: MIT Press

This interview was recorded Thursday, 18 April 2013.
Audio engineer: Francesco Ferorelli

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