We tend to think of cities as environmentally unfriendly places, but at least one economist believes that cities are actually more eco-friendly than suburbia.
Concrete jungles: Mother Nature's pride and joy
We tend to think of cities as over-populated, resource-sapping places whose inhabitants' lifestyles only add to climate woes. But as Laura Collins learns, at least one economist sees urban life as an Earth-friendly alternative to suburbia.
More than half the world's population is urban. Every month another five million occupants swell the cities of the developing world. By 2050 it is estimated that 70 per cent of us will live in a city.
Little wonder that, according to geologists, we have entered the Anthropocene Age: an age defined by man's massive impact on the planet.
To many this is cause for alarm. Because when it comes to the environment, everybody knows "urban" is a dirty word - right?
Not exactly, according to a Harvard professor of economics, Edward L Glaeser. For the past two decades the 40-year-old New Yorker has devoted himself to the study of cities - how they work and their local, global, cultural and environmental impact. His conclusion on this last point, now published in his book The Triumph of the City, is startling.
Cities, in Glaeser's view, are our "greatest achievement", and living in them not only makes us "richer, smarter, healthier and happier", but it also makes us greener.
"Cities are much better for the environment than leafy living," he says. "Residing in a forest might seem to be a good way of showing one's love of nature, but living in a concrete jungle is actually far more ecologically friendly."
As counter-intuitive as it may sound, Glaeser is adamant: "Manhattan and downtown London and Shanghai, not suburbia, are the real friends of the environment. Nature lovers who live surrounded by trees and grass consume much more energy than their urban counterparts."
Suburban environmentalists and conservationists who have fought to keep neighbourhoods "green" and building heights low "had it backward," he says. Few slogans, according to Glaeser, are as silly as the environmental mantra, "Think globally, act locally".
For many who strive to do just that this will come as a slap in the face. It might be tempting to dismiss Glaeser's apparently contrary standpoint as a not-too-subtle bid to shift books. But Glaeser's arguments are not the overblown sound bites of a self-promoter. They are the result of meticulous research over a distinguished academic career that has seen him recognised as one of the world's most brilliant economists and authorities on cities.
"If the environmental footprint of the average suburban home is a size-15 hiking boot," he says, "the environmental footprint of a New York apartment is a stiletto-heel, size-six Jimmy Choo."
Cities with their enforced proximity are the friend, rather than the foe, of the green spaces that surround them, he says. The encroaching sprawl of "leafy suburbia" - its larger houses consuming more energy, and its inhabitants driving far greater distances than their urban counterparts - merely turns green spaces brown.
"It's important to differentiate between the energy used in the process of development, where it's certainly true that richer countries use more energy, with the energy that's involved in cities," Glaeser says. "What I'm arguing against is the American tendency to strongly subsidise suburban living. That's a profound mistake."
It's a mistake that stems, in part, from what Glaeser describes as the "strong idealisation of rural life".
"Historically, of course, cities were far more dangerous than rural areas in terms of disease and peril," he admits. "Don't get me wrong, I'm not trying to sugar-coat urban living. For every Fifth Avenue there's a Mumbai slum; for every Sorbonne, there's a DC high school guarded by metal detectors."
Turning his attention to the UAE, Glaeser concedes that the recent economic downturn may have exposed an "excess of exuberance" when it came to developing Dubai out of the sand. But he finds nothing in the stalled building work or curtailed ambitions of the Emirates' largest city that leads him to doubt the fundamental idea that inspired it.
"I think the core idea of Dubai, as far as I understand it, is sound," he says. "Think about it. Over the last 75 years it's had this extraordinary evolution as a city built on natural resources and moving them across space. There's nothing fundamentally flawed in that. Dubai as a city can continue to succeed and evolve. It will do so by having better institutions than its neighbours, better legal and political infrastructure. I think the UAE is a place that understands that it has to attract global talent in order to succeed and that's what it's setting about doing. Any downturn challenges the world and its cities. Yet our urban future remains bright."
And if we embrace what Glaeser refers to as "urban height" rather than suburban sprawl, the bright urban future will also be a green one.
Edward L Glaeser's The Triumph of the City: How Our Greatest Invention Makes Us Richer, Smarter, Greener, Healthier and Happier is out now.