How Green Is Your Metropolis?

Normally, a special election for California’s State Assembly wouldn’t have much national significance — especially not an election in San Francisco, a liberal, Democratic city that’s the opposite of a swing district.

But this particular election was fought largely over housing policy. The winner had the backing of the newly rising Yimby — Yes in My Backyard — movement that has emerged in opposition to Nimbyism, calling for more housing construction and higher urban population density. And if this is a straw in the wind for national policy, the consequences for both the economy and the environment could be hugely positive.

Some background: On the eve of the coronavirus pandemic, America’s big cities were in many ways in better shape than ever before in their history. Urban social problems hadn’t vanished, but they had receded. In New York, in particular, homicides were down 85 percent from their level in 1990. At the same time, the knowledge economy was drawing businesses to large, highly educated metropolitan areas.

For a little while it seemed as if the pandemic might reverse these gains: The coronavirus hit New York hard during its early months, and there were many assertions that high population density was a health hazard. As we learned more about how to deal with the virus, however — and especially after vaccines became available — densely populated urban areas became substantially safer than rural areas, if only because their residents were more willing to wear masks and get vaccinated.

It’s true that crime, especially shootings, rose sharply during the pandemic. But this is not restricted to big cities. And even now New York’s crime rate is considerably lower than it was when, say, Rudy Giuliani was mayor. (Whatever happened to him?)

And if housing markets are any indication, big cities’ appeal has rebounded. Rents in New York fell sharply during the worst of the pandemic, but they have now fully reversed that decline.

Which is a problem. You see, cities have become highly desirable places to live and work; as I’ll explain in a minute, they’re also good for the environment. But they’ve become increasingly unaffordable, largely because of local-level opposition to new construction.

Where does this opposition come from? There has always been a segment of U.S. opinion that views dense urban living as inherently dystopian. Senator Tom Cotton was widely mocked when he tweeted (falsely) that Democrats “want to make you live in downtown areas, and high-rise buildings, and walk to work, or take the subway” as if this lifestyle — which quite a few of us find appealing — was horrible. But many Americans probably share his views.

Some of the opposition also reflects selfishness: Affluent residents of expensive communities often want to keep housing prices high by restricting the housing supply.

But a significant proportion of the opposition to density may reflect honest misunderstandings of what density does.

According to a recent YouGov survey, threeof four Americans believe that it’s better for the environment if houses are built farther apart. And you can sort of see why they believe that. Someone who lives in a leafy suburb, let alone in a rural area, is surrounded by more greenery than someone in an urban high-rise. So wouldn’t the nation as a whole be greener if everyone spread out more?

The answer, of course, is no, because this seemingly common-sense view involves a fallacy of composition. Imagine taking a square mile of Manhattan holding about 70,000 people — which, by the way, is much quieter and feels much less crowded than people who haven’t lived in such a neighborhood can easily imagine — and spreading its population out to a typical suburban density. These people would then occupy about 35 square miles. The footprint of their houses, the roads they need to get around (because everything has to be done in a car), their shopping malls and so on would end up paving over far more green space than they used in New York.

Dense cities also use much less energy per capita than suburbs, largely because their residents drive less, relying instead on walking and various forms of public transit, including the extremely efficient mode known as the elevator.

So while nobody is suggesting that we force Americans to live like New Yorkers, allowing more people to live that way by permitting more density would be good for the environment.

It would also be good for the economy. Some people are willing to pay very high prices for urban housing because they’re more productive in big cities. So limiting density makes America poorer, by preventing workers from making the best use of their talents. One recent study estimated that reducing land-use restrictions in a few major cities would add 3.7 percent to U.S. gross domestic product — that is, almost $900 billion a year.

So let’s hear it for Yimbys. Opposition to urban density has done a remarkable amount of harm. Reducing that opposition could do a surprising amount of good.

The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: [email protected].

Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram.