5.29.2008 7:45 AM

The Greenest U.S. Cities (Are Not What You Think)

Honolulu and, Yes, Los Angeles Top the List

Smog-filled highway, Los Angeles.

Photo: David McShane/ Istock

By Dan Shapley

How can Hawaii, which relies on oil to import 80% of its food 2,500 miles from the mainland, have the greenest city in the United States?

How could the smoggy, sprawling capital of traffic-snarled Southern California rank second?

It seems incredible, but Honolulu ranked first, and Los Angeles, Santa Ana and Long Beach together ranked second, in a new Metropolitan Policy Program at Brookings analysis of greenhouse gas emissions from the 100 largest metropolitan areas in the United States.

The worst polluters were clustered in the Southeastern U.S., and all but one of the top 10 worst polluters was east of the Mississippi.

One important caveat: The scores were based on carbon dioxide per resident, so the jet flights from all those tourists that make Honolulu's economy work don't count against it. In fact, airplane traffic isn't included in the analysis at all. Nor are commercial buildings. Here's how Brookings describes the limitations of its data:

"To produce comparable carbon footprints for the 100 largest metropolitan areas, the authors examined national databases for passenger and freight transportation and for energy consumption in residential buildings. These estimates are as current as data sources will allow across metro areas, yet at the same time they are incomplete. Major omissions are the carbon emissions from commercial buildings, industry, and other modes of transportation such as planes, transit, and trains. These sources account for roughly half of national emissions. For this reason, results for any particular metropolitan area should be treated with caution. Still, the majority of commercial buildings are powered by electricity derived largely from coal, and their spatial arrangement would be expected to follow the general compactness and density characteristics of residential developments in a metro area. Thus, their footprints are likely to resemble those reported here for residential buildings, although this remains to be seen."

Neysa C. Pranger, director of Public Affairs for the Regional Plan Association, a partner in the report, added this about Los Angeles:

"Emissions numbers for California used a statewide average. Apparently in northern California, energy production is very green, while in southern California it is not so good. The break down couldn’t happen with a high degree of accuracy, so the report uses a statewide average which made LA look better than it is."

Still, many of the points made in the report have obvious merit:

We need better public transportation and smarter housing developments that cluster homes within walking or biking distance from work, school, entertainment and transit hubs. Why? It will cut down on the need for people to drive so frequently, or so far. In other words, we need to rein in sprawl and retrofit suburbs so they can reach a sustainable level of energy consumption.
Transportation accounts for 33% of the nation's greenhouse gas emissions, with car traffic representing the biggest slice of the transportation pie (though freight and light trucks together account for more).
We need to tell home buyers how much their monthly energy bills will be, so they can factor that into mortgage financing to "stimulate and scale up energy-efficient retrofitting of residential housing." Not only that, but the new houses we build need to be smaller and more energy-efficient. Buildings (commercial and residential, but not industrial) account for 38% of the nation's greenhouse gas pollution.
We need to use electricity more efficiently, a challenge that grows more acute with every new computer, video game, cell phone or other electronic device plugged into the wall. Electricity use accounts for more than half of most home's energy consumption, though heating and cooling also represent big contributions – bigger the bigger the home.
We need to make sure federal incentives promote sound land- and energy-use decisions, so we stop subsidizing commuting and sprawl.

The overriding point of the report is this: Cities and metropolitan areas are more highly efficient than sprawling suburbs, and there's also more room for improvement to sustainable energy use in the nation's largest metropolitan areas, where two-thirds of the population lives. Among the metropolitan areas (a Census term that lumps some adjacent cities and suburbs into single units) the worst cause up to three times more pollution than the best.