Saturday, October 9, 1999

Population Growth and Sprawl

This was originally written for a Sierra Club mailing list in October, 1999.

I'm a little disappointed that the discussion of sprawl and population growth has been so polarized. On the one hand, some people argue that an infinitely growing population is not a problem; on the other, some argue that it is the "key driver of environmental destruction," implying that it is the primary cause of sprawl. Neither is true.

Population growth is an important environmental issue. It's clear that, in general, more people on the planet mean that more resources must be used to support them. More land must be taken from wild use and put toward agricultural use or used for housing. Technological fixes such as the so-called "green revolution" have decreased biodiversity and jeopardized our food supply by making it vulnerable to epidemics. Genetically engineered food plants come with their own sources of danger. So population growth must be recognized as a serious problem, and one that we as Club members should be helping to solve.

On the other hand, we must also recognize not everything bad is the result of population growth. Growing population by itself is not the source of our problem with sprawl. Rust Belt cities that have had shrinking or stable populations still have expanded pell-mell into the countryside. An increasing population is not responsible for the loss of wild and rural land around Buffalo, Providence, and similar cities. We cannot eliminate sprawl simply by limiting population growth.

Does that mean we should accept population growth as a good thing? Not at all. But we may realize that it's easier to guide the floodwaters to a floodplain than to try to put up a dam. We need to have more than one strategy for dealing with growth -- try to stop it, but if we cannot (and we should not pretend we have control over it when we do not), direct it so that it is more sustainable than it would be otherwise.

So what does cause sprawl?

Sprawl is new construction happening at the fringes of the urbanized area instead of in already developed areas. It's absolutely true that one reason sprawl happens is because population and employment growth require new construction, and new construction is now occurring predominantly at the edge.

But population growth is far from the only thing that causes new construction. There are many reasons that workplaces and housing are taken down in the center and rebuilt at the fringes. Sometimes this is because the buildings are old and dilapidated. Sometimes this is because they occupy space that people wish to use for other purposes. (Parking lots have been a major cause of displacement.) Sometimes they are simply obsolete.

Sprawl is caused by all these changes moving the city outward. Even a city with no population growth will still experience change in its buildings. Stopping sprawl will entail redirecting this development back inward, to already developed areas, instead of out on the fringe.

What about "smart growth"?

Somehow the idea that there are better and worse ways to grow got transmuted into the idea that there are good and bad ways to grow -- a small but important distinction. It is still useful to discuss forms of development that are "smart" and those that are "dumb," even if we are trying to reduce growth overall.

What kind of cities should we have?

The question of sprawl comes down to what kind of cities we should have. Should our cities spread out across the landscape or be limited to compact urban areas?

This question is still valid whether or not there is population growth. Even if there were population *shrinkage*, it would still be a valid question to ask which is more environmentally sustainable: spread-out development or compact development? Population shrinkage would make the question less urgent, as unsustainable activity would have a larger resource base to consume, but no less relevant.

I suppose someone might make a case for a spread-out city as one that's better environmentally, but I haven't heard one yet, and frankly I'd be very skeptical. The case for compact cities is really pretty simple: that "reduce, reuse, recycle" should be applied to land use as well as consumable goods. The more land we build on, the less land is available for wild land and more environmentally friendly uses.

Carrying capacity

It's been said that we need to live within the carrying capacity of the planet; we need to ensure that we don't exceed the capability of the natural resources to sustain us. This is absolutely true. However, the amount of natural resources we consume is not a fixed amount per person. Someone who does not have a lawn uses a lot less water than someone who does. Someone who lives in a small apartment requires less heat than someone who lives in a large house. Living within our carrying capacity has to be about how we live as well as how many we are.

What about choice?

It's been argued that cities should have the choice whether to be compact or whether they should be spread out. I am always surprised to hear this argument from environmentalists. Normally, environmentalists do not argue that it should be a choice whether to have a citywide recycling program or not, or to log one's own stand of old growth forest, or take other environmentally damaging action. But apparently it's supposed to be OK to choose a spread-out city over a compact city.

We need to recognize that "People should be able to choose" is not an environmentalist argument. It is an argument that ignores our moral responsibility for preserving the natural environment, for its own sake or for the sake of future generations. It might be argued that a difference lies in this choice being made by a community rather than an individual. But, even if this were true (and it is not; decisions on such issues as solid waste disposal are made by cities) our communities do not end at the city limits.

Of course, the arguments have been made many times that in fact our society skews choices towards the outer fringe away from the center. The low supply of new housing, decisions made by our employers, the economies of scale of new developments on the edge, all encourage us to move outward rather than inward, even if that's not what we might otherwise like. When we ask people what they'd like to live in, they often identify kinds of buildings that aren't available given other constraints on their choices. This needs to be rectified.

In practice, building choices are very slow to change. We already have a tremendous amount of sprawl development that has been built since the 1940s. Those who prefer that sort of living will have that choice for a very long time to come. But future developments need to take into account the environmental costs of that choice.

What makes a community livable as well as sustainable?

Books have been written, and will no doubt continue to be written, about this issue. I don't think "livability" is something that can be measured. It's a fundamentally subjective feeling that a place is an appropriate one in which to spend time.

It's clear that some people seem to find spread-out suburbs better places to live, and some people compact cities. We're not going to magically bring everyone to agreement on this issue in this forum.

But I think it can be said without fear of contradiction that cities can be good places to live, and millions of people enjoy compact city life and find it a positive experience. The Club's web site at is a good start to explain how some people, at least, believe it to be so.

It is my belief that when an alternative is preferred by many people, and is shown to be more sustainable, it is something environmentalists should be advocating. That isn't to say we should advocate the wholesale return of the suburbs to wild conditions, any more than we have pushed for the elimination of disposable forks and plates, or the elimination of all private forestry. But it does mean that we need to see sprawl as an issue that's not just an individual choice. We need to see living and working in the central city the way we see choosing to use recycled goods -- often just common sense and not necessarily deserving of accolades, but as something that nonetheless is clearly preferable to the alternative, from an environmental perspective.

Isn't it all about transportation?

I suppose somebody, somewhere, must be in favor of compact cities only in order to make transit work. But the linkage between land use and transportation isn't just one way.

A spread-out city doesn't work well with transit because there are not enough origins and destinations close to the transit stops to make them practical. But it's also true that a compact city doesn't work well with cars, because the space required to park the cars is very great. That requires either very expensive parking garages (limiting the ability of the city to build compactly; only those uses that provide a high economic return can afford to ) or the provision of large parking lots (thus making the city less compact).

It's a bit of an oversimplification, but in essence there are two kinds of cities: spread-out car cities and compact transit cities. In practice, we have real spread-out car cities in the suburbs, which have all the environmental problems of sprawl, and a sort of half-way mixed system in most of our central cities, with inadequate transit and many parking lots that end up pushing development further outward and also make the city feel less connected, and thus less livable. This is the result of decades of mistreating our central cities. This is something that needs to end.

Isn't density bad?

Density just means putting more things in less space. Using less land for the same population.

There are real reasons why density has a bad name, but they are not intrinsic to building at a higher density than is typical in sprawl. For example, since density generally requires larger structures, a bad design for a structure has a greater impact, and there are an awful lot of really bad buildings out there: International Style buildings that are alienating and not on a human scale. This really is a matter of design rather than density per se. Many of the Brutalist college campus buildings of the 1950s and 1960s are not particularly dense, but are just as alienating and have an equally negative effect. The answer here is relearning patterns of architecture from prior to Modernism. Architects need to design buildings that fit fit the pattern of street development and not break out of it as an artistic statement.

Another reason density has a bad name is because of the blockage of light. This is one of the main reasons that the "anti-Manhattanization" movement in San Francisco was started. Of course, the very parts of San Francisco that were most negatively affected by shadows cast by buildings from the the '80s building boom are far, far more dense than anything in the suburbs. There is a limit to how high buildings can go without causing shadow problems, of course, and we do need to be careful, but there's a lot of middle ground between the typical suburb and Hong Kong.

Finally, the most common reason one hears to argue against density is because density brings cars, and they bring traffic congestion, noise, and pollution. I shouldn't even need to point out that the cars, not the density, are the problem here.