is the president and chief executive officer of the Congress for the New Urbanism
Former Vice President Al Gore deserves his Oscar for An Inconvenient Truth. The movie is a hit, with more than $48 million in box office receipts. In calling people across the world to address a common threat, Gore has rung a fire bell in the night. Now we're awake, but what do we do?
Here's what Gore suggests: Change a light, drive less, recycle more, check your tires, use less hot water, adjust your thermostat, plant a tree, turn off electronic devices, and, naturally, buy his DVD.
It's a start, but not even Gore can think of everything. One huge omission is how and where to build the 70 million new homes projected for the United States by 2037. When it comes to energy consumption and carbon-dioxide emissions, development patterns matter.
High-rise cities like Philadelphia and New York rarely come to mind as models of environmentalism, but they should. With people living closer to each other, walking more and taking advantage of public transit, cities have powerful environmental advantages.
A report prepared for New York Mayor Michael Bloomberg's green blueprint, PlaNYC, revealed that New Yorkers generate, on average, 7.1 metric tons of greenhouse gases a year, two-thirds less the average 24.5 metric tons generated by most Americans.
Of course, not everyone can be - or wants to be - a dweller of New York or Center City Philadelphia. The good news is that a variety of neighborhoods help reduce greenhouse-gas emissions.
A 2002 peer-reviewed study by John Holtzclaw and other researchers examined odometer readings from annual government-run vehicle emissions tests to compare driving patterns across metro Chicago, Los Angeles and San Francisco. It showed that miles driven by an average household dropped between 32 percent and 43 percent as the density of neighborhoods doubled.
In other words, in moving from a typical exurban neighborhood with three units per acre to a neighborhood like Manayunk - where densities are at least 24 to the acre - a household would expect to reduce its driving to about 32 percent what it formerly was. A move to the tight-knit heart of Haverford or downtown Ambler would yield about a 50 percent reduction.
With a switch to far-more-efficient transit for some of their trips and walking for some others, that's a big reduction in the annual tonnage of carbon a household sends into our atmosphere.
Now the enjoyment of a yard and the freedom to load up a car or pickup and hit the road are an assumed part of the American identity, and that's not necessarily the problem. The problem is how much you use that pickup.
Americans' extreme driving patterns stem directly from zoning codes and freeway-based transportation systems that became the norm in the last 50 years. An overextension of well-meaning Progressive-era efforts to save poor city dwellers from foul-smelling factories, today's standard zoning requires homes to be in subdivisions, offices in office parks, stores in malls or along big-box strips, even places of worship safely away from any chance that they'll be reachable on foot.
Fortunately, alternatives are gaining momentum. San Francisco, Portland and Milwaukee have replaced freeways with boulevards. Miami is one of several cities reworking its zoning to encourage neighborhood-based development. Hurricane-damaged Gulfport, Miss., just adopted an alternative code that will help create neighborhoods of character and value, not sprawl.
Hybrid or hydrogen cars, solar panels, and green gizmos may all play important roles in addressing global warming, but they'll require either technological breakthroughs or personal financial sacrifices. Smarter development can happen now.
In the next 30 years, our country will build 70 million new dwellings somewhere. With urban life emerging as a market favorite, it's looking more as if building a good portion of them in livable, walkable traditional neighborhoods is one of the most convenient - and effective - remedies for the inconvenient truth.