SEATTLE - Ron Sims, King County executive, has a simple test for every new public works project, building plan, or government land purchase: Will it increase the region's total greenhouse-gas emissions, or reduce them?
"We are totally committed to reducing emissions, but it requires rethinking the way we do our activities," Sims explained. "People are saying, 'But we've always done it this way.' We're saying, 'That way doesn't work in an age of global warming.' "
Officials in King County and other places are rethinking the way their communities grow and operate, all with an eye toward reducing their overall carbon footprint. After decades of policies that encouraged people to move out to the suburbs in pursuit of larger homes and bigger backyards, some policy makers are now pushing aggressively to increase urban density and discourage the use of private cars.
In Massachusetts, the state demands that developers calculate and disclose the climate impact of their projects. In California, Attorney General Edmund G. "Jerry" Brown Jr. has sued communities and power companies for failing to offset the greenhouse gases generated by their expansion plans. And Washington, D.C., officials are installing a new trolley line and bike rental kiosks in an effort to cut back on car trips within the city.
Even though national politicians are beginning to consider a federal carbon cap more seriously, the flurry of activity in state and local jurisdictions highlights a little-noticed reality: Most of the measures to reduce greenhouse-gas emissions will be enacted outside Washington.
"The vehicle for delivery, in terms of achieving greenhouse gas reductions, is often going to be the states," said Ian Bowles, the secretary of energy and environmental affairs in Massachusetts. "It's going to happen through things like building codes, utilities, and zoning."
But not without occasional resistance. Brown has sued entities as varied as San Bernardino County and petroleum company
He reached settlements with both last year: San Bernardino officials agreed to estimate the county's 1990 and current emissions levels, analyze how its land-use decisions will affect its emissions by 2020, and develop a plan to cut emissions stemming from its land-use policies and government operations. ConocoPhillips agreed to pay the state $10 million to offset the climate impact of expanding its oil refinery in Rodeo, Calif.
Brown, however, acknowledges that government alone cannot change where Americans decide to live and work. "It really takes a sea change in attitude, a shift in how the urban and suburban are perceived," he said in an interview. "It's not something that government can just mandate without a change in how the public views it. You can't just order it into being."
Some public officials are relying more on incentives than penalties to reduce sprawl. Bowles, who noted that Massachusetts has 351 cities and towns that each set their own zoning laws, said state officials are hoping that requiring developers to disclose their emissions will encourage them to build more efficient projects.
"It's a lighter touch," he said, adding that officials can drag out the permitting process if they decide a developer is not cooperating. "At its core, it's an analytic requirement that says find ways to reduce your emissions."
Harriet Tregoning, director of the D.C. Office of Planning, said Washington is operating on "a pleasure principle," meaning that steps taken to reduce emissions should also make the city more attractive.
Several environmental and planning specialists warned that unless cities and counties take active steps to limit sprawl now, the United States will find it nearly impossible to make deep cuts in greenhouse gas emissions in the decades to come.
Sims, who testified before the Senate Environment and Public Works Committee in November, noted that because people are commuting greater distances each year, the increase in carbon dioxide emissions from transportation by 2030 will far outpace any gains the country makes in fuel efficiency. Compact development, by contrast, could reduce metropolitan carbon dioxide emissions by roughly 20 percent, said Reid Ewing at the University of Maryland's National Center for Smart Growth.
The goal of land use planners is not to cut emissions right way, recognizing that it will take decades for that to happen, but to ensure that development doesn't drive up a region's greenhouse gas output.
Even as some states in the Northeast and West are working aggressively to curb their greenhouse-gas emissions, the proliferation of exurbs in the Southeast is exacerbating the problem. Six Southeastern states - Alabama, Georgia, North Carolina, South Carolina, Tennessee, and Virginia - would rank as the world's seventh-biggest emitter if they were a single country.
Ewing has calculated that residents of Atlanta and Raleigh drive more than 30 miles a day per person, while Boston and Portland, Ore., residents drive less than 24 miles a day in their more compact cities. More compact development could cut the US transportation sector's greenhouse-gas emissions by 7 percent to 10 percent, Ewing and his coauthors wrote in their new book, "Growing Cooler."