How to Build a Greener City

נשלח 14 בספט׳ 2011, 1:40 על ידי Sustainability Org   [ עודכן 14 בספט׳ 2011, 1:50 ]
SEPTEMBER 12, 2011, by Michael Totty, The Wall Street Journal

Bike lanes, micro wind turbines, pneumatic garbage collection—and other ways to make urban areas more environmentally friendly

Can cities be part of the environmental solution instead of part of the problem?

The question isn't an idle one. Urban populations around the world are expected to soar in the next 20 years, to five billion from more than three billion today. If the current rate of urbanization holds steady, cities will account for nearly three-quarters of the world's energy demand by 2030. Most of the increase will come in rapidly developing countries like China and India; China's cities alone will have to deliver water, housing, transportation and other services to 400 million additional urban dwellers by 2030.

So, cities aren't going to have be made a little greener; they're going to have to be rethought from the ground up. The goal: compact living environments that require less resources and that get the most out of the land, water and energy they do use.

"There's going to have to be new forms of energy, new ways of delivering energy and new forms of infrastructure," says Warren Karlenzig, president of Common Current, a consulting firm on sustainable cities based in San Anselmo, Calif. "All this will be necessary to allow cities to operate the way they do now."

It wasn't long ago that the idea of using "green" and "city" in the same sentence seemed absurd. Cities were considered a blight on the environment: energy-hogging, pollution-spewing, garbage-producing environmental hellholes. But in recent years, they've begun to be seen as models of green virtue. City dwellers tend to walk more and drive less than their suburban counterparts, and dense urban development encourages transit use. Apartment living generally means lower per-household energy use.

Building on these strengths, planners and developers are devising innovative solutions to meet urbanites' energy, water, transportation and sanitation needs well into the future.

Some improvements are fairly easy, such as switching to energy-efficient LED lighting in buildings and streetlights, or setting aside bike lanes and widening sidewalks to encourage alternatives to driving (although such moves aren't without political hazards, as a recent battle over bike lanes in New York shows). Others are more ambitious, requiring new construction or even an extensive rebuilding of city infrastructure—consider what is needed to add a second set of pipes for a water-reuse system.

Some of the most ambitious projects—and the greatest source of innovative ideas—are the dozens of "eco-city" developments in the works or on drawing boards around the world. Projects like the Songdo International Business District near Incheon, South Korea, are testing grounds for the latest in green technologies.

But green initiatives aren't just found on blueprints for new cities. Chicago, for example, has about 350 green-roof projects covering more than 4.5 million square feet.

Of course, many of these initiatives can be expensive, with high up-front costs. Urban planners say savings from lower energy bills and other operational efficiencies can more than cover the added expenses, but the break-even point can be years out. Still, cities—unlike the average homeowner considering rooftop solar panels—can take a long view and make investments with a decades-long payback.

So, how can cities—old or new—take green to a new level? Here's a look at some of the ways.

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