GraffitiPhoto: ruminatrixAnyone who thinks that cities are key to the future of a sustainable human presence on the planet — and anyone who thinks the contrary — should read Jonah Lehrer’s fascinating piece in yesterday’s New York Times Magazine, “A Physicist Solves the City.”

In it, Lehrer examines the ideas of Geoffrey West, a theoretical physicist who (with his colleague Luis Bettencourt) has come up with a variety of mathematical equations that attempt to define and explore the essential nature of cities. (West’s and Bettencourt’s work was also featured on a recent excellent episode of Radiolab that I discussed in an earlier post.)

As Lehrer writes, “West considers urban theory to be a field without principles, comparing it to physics before Kepler pioneered the laws of planetary motion in the 17th century.”

And so he set out to discover those laws — proceeding on the assumption that they exist, and can be mined and refined from the chaos of urban life.

West first noticed the similarities between cities and living organisms:

This implied that the real purpose of cities, and the reason cities keep on growing, is their ability to create massive economies of scale, just as big animals do. After analyzing the first sets of city data — the physicists began with infrastructure and consumption statistics – they concluded that cities looked a lot like elephants. In city after city, the indicators of urban “metabolism,” like the number of gas stations or the total surface area of roads, showed that when a city doubles in size, it requires an increase in resources of only 85 percent.

But West and his colleagues then realized was that the true essence of a successful city can’t be explained by efficiency:

[A] city is not just a frugal elephant; biological equations can’t entirely explain the growth of urban areas…. “In retrospect, I was quite stupid,” West says. He was so excited by the parallels between cities and living things that he “didn’t pay enough attention to the ways in which urban areas and organisms are completely different.”

What Bettencourt and West failed to appreciate, at least at first, was that the value of modern cities has little to do with energy efficiency. As West puts it, “Nobody moves to New York to save money on their gas bill.” Why, then, do we put up with the indignities of the city? Why do we accept the failing schools and overpriced apartments, the bedbugs and the traffic?

In essence, they arrive at the sensible conclusion that cities are valuable because they facilitate human interactions, as people crammed into a few square miles exchange ideas and start collaborations. “If you ask people why they move to the city, they always give the same reasons,” West says. “They’ve come to get a job or follow their friends or to be at the center of a scene. That’s why we pay the high rent. Cities are all about the people, not the infrastructure.”

The agglomeration of all those people leads to a lot of innovative thinking — which is good, because we need the innovations to keep pace with our ever-growing appetites. (See some recent related discussions of David Owen’s New Yorker article on energy efficiency and the Jevons paradox).

Lehrer writes this about West’s evolving thinking on the city and its role as a hotbed of innovation:

There is a serious complication to this triumphant narrative of cliff edges and creativity, however. Because our lifestyle has become so expensive to maintain, every new resource now becomes exhausted at a faster rate. This means that the cycle of innovations has to constantly accelerate, with each breakthrough providing a shorter reprieve. The end result is that cities aren’t just increasing the pace of life; they are also increasing the pace at which life changes. “It’s like being on a treadmill that keeps on getting faster,” West says. “We used to get a big revolution every few thousand years. And then it took us a century to go from the steam engine to the internal-­combustion engine. Now we’re down to about 15 years between big innovations. What this means is that, for the first time ever, people are living through multiple revolutions. And this all comes from cities. Once we started to urbanize, we put ourselves on this treadmill. We traded away stability for growth. And growth requires change.”

Ultimately, West’s research affirms his belief in the organic resilience of megalopolises. But is he right? Is this real science? Can cities continue to grow without collapsing in on themselves?

With more than 50 percent of the world’s populations now living in urban areas, much depends on the answer.