When I lived in Seattle, I was driving a friend home when she said she didn’t like all the new buildings because they pushed poor people out of the city. I was confused by her argument and that building more housing units will make it easier for poor people—any people, really—to afford to live in the city, but she argued that wasn’t true because the existing buildings were “worse.” But that doesn’t matter much: if a given parcel of land goes from having four units on it to four hundred, that’s vastly more supply. The conversation’s already low level of intellectual content degenerated, but I thought of it as I read Triumph of the City, which gathers a lot of useful information about cities and what they offer in one place. Yes, the title is overwrought, but the content is useful, and I especially noticed this, about Jane Jacobs:

Because she saw that older, shorter buildings were cheaper, she incorrectly believed that restricting heights and preserving old neighborhoods would ensure affordability. That’s not how supply and demand work. When the demand for a city rises, prices will rise unless more homes are built. When cities restrict new construction, they become more expensive.

It’s basic supply and demand, but, from what I can tell, relatively few cities actually discuss supply, demand, and housing costs—which is unfortunate given the extreme costs of many desirable cities that offer intensive knowledge spillover effects. If how we live affects what we think and how we think, we should pay a lot of attention to how we live. Yet few of us do, though more of us should. Triumph of the City is the kind of book unmoored young people and people contemplating career changes need to read, because where you live affects so much of how you live. This part speaks to a dilemma I’m facing:

In the year 2000, people were willing to accept lower real wages to live in New York, which means that they were coming to New York despite the fact that higher prices more than erased higher wages. It’s not that New York had become less productive; the city’s nominal wages, which reflect productivity, were higher than ever. But housing prices, fueled by the robust demand to live and play in the city, had risen even more than nominal earnings. If housing prices rise enough relative to nominal incomes, as they do when cities become more pleasant, then real incomes can actually fall during a period of great urban success. Manhattan had changed from a battlefield to an urban playground, and people were willing to pay, in the form of lower wages, for the privilege of living there.

I’m likely to move to New York and live for at least two years. Which raises questions: am I willing to “accept lower real wages” because of the housing cost increases? How valuable is “an urban playground?” Perhaps not valuable enough to keep me there. I love New York and just wish I could live there. L.A. has similar problems, and I have some friends who want to leave Tucson—for which I blame them not at all—and are contemplating where to go; based on their disposition and temperaments, Seattle or Portland would be obvious choices. They’re much less expensive, and moving to either will probably result in an increase of 10 – 20% in real income terms, as Virginia Postrel shows in “A Tale of Two Town Houses.” (Glaeser speaks to L.A., too, however indirectly: “Cities grow by building up, or out, and when a city doesn’t build, people are prevented from experiencing the magic of urban proximity.” L.A. has replaced proximity with traffic.)

And there tend to be clusters of artists and other creative types in cities that offer dense environments, not totally dysfunctional politics, and cheap housing. The 1920s Paris immortalized by Hemingway and Fitzgerald, and recently recreated in Woody Allen’s Midnight in Paris was such a place; today, as Glaeser says, “Restrictions on new construction have ensured that Paris—once famously hospitable to starving artists—is now affordable only to the wealthy.” It’s a useful reminder that you can’t beat economics with raw policy alone, and so many articles about rising rent prices or changing demographics utterly fail to connect housing costs with the needs of the poor outsiders who will one day start startups or be artists (for a recent, positive example, see Megan McArdle’s post “Empty Apartments, Stupid Laws“).

Artists simply can’t afford Paris anymore, and New York is becoming expensive too.

The really famous, important parts of the world—New York, London, Tokyo, Beijing—are important because of what large networks of hundreds of millions of people have done with and to them. They’re not intrinsically important because of the land they occupy. Cities that want to emulate their example and distinguish themselves from surrounding suburbs and rural lands need to build up, not out (or not at all). New York’s housing prices are so high because lots of people want to live there—because it’s awesome. As Glaeser shows, we should want them to be able to live there, too. But we often can’t.

This doesn’t just hurt us as individuals, or economies composed of people who can’t live in spaces where they connect with one another: it also hurts the environment because: “Traditional cities have fewer carbon emissions because they don’t require vast amounts of driving. [. . .] Department of Energy data confirms that New York State’s per capita energy consumption is next to last in the country, which largely reflects public transit use in New York.” And:

Good environmentalism means putting buildings in places where they will do the least ecological harm. This means that we must be more tolerant of tearing down the short buildings in cities in order to build tall ones, and more intolerant of the activists who oppose emissions-reducing urban growth.

But I think he misses something here: for a lot of people, environmentalism is just a pose, a way to show they care—provided it doesn’t harm or affect their life in some immediate, substantial way (those of you firing up your e-mail clients to send me angry missives should hold off: this applies to lots of other subjects too, like religion). So the people who claim to be environmentalists are really claiming that they want you to think they care about the environment, and that’s a cheap stance until people start to complain about construction noise, or loss of a neighborhood’s dubious “character,” or whatever other excuse comes up. As Alex Tabarrok says in Launching The Innovation Renaissance, one major, underappreciated problem the U.S. faces is the sheer number of veto players who can affect any building project at any scale. Glaeser is in effect pointing to a single facet of this general principle.

In essence, there’s too much regulation of what happens in most cities. For example, take parking policies: if people (especially those who claim to be environmentalist) want good public transportation, one useful strategy is to raise the real cost of cars, which is an especially good idea because Free Parking Comes at a Price. And that price is innumerable underutilized parking spaces. I see this price every day in Tucson, where miles and miles of land are given over to hideous parking lots that make walking virtually anywhere impossible.

One interesting missing piece: a concrete theory of why cities offer the advantages they do. We have lots of indirect information showing the advantage of cities, combined with some theories about why they offer the things they do, but little else. Steven Berlin Johnson is similarly indirect in Where Good Ideas Come From; like Triumph of the City, it’s a fascinating book (and he speaks to cities as innovative environments in it), but it also has this gap that I don’t know how to fill. Perhaps no one can at current levels of technology and understanding.

A lot of the prose in Triumph of the City is uninspired, and occasionally garbled, like this: “Urban proximity enables cross-cultural connection by reducing the curse of communicating complexity, the fact that a garbled message increases the amount of information that is being transferred.” But the density of ideas makes up for the weakness of the language, and Glaeser is also a native economist, rather than a writer.

Here’s Slate’s (positive) review. I don’t think I’ve read any negative reviews; if you’ve seen any, post a comment.