Washington —- Metro Atlanta, with its far-flung suburban neighborhoods, has a larger per person "carbon footprint" than denser cities, including Los Angeles and New York, a study by the Brookings Institution concludes.

The report, released today by the Washington research and policy group, measured fuel use for highway travel and residential buildings —- which Brookings called "the most significant sources" of carbon emissions —- in the 100 largest U.S. metro areas in 2005.

The average carbon footprint of Atlantans ranked among the highest one-third of the major cities, just below Baltimore.

The release of carbon into the atmosphere is linked to the use of fossil fuels and blamed for climate change and U.S. dependence on foreign oil.

"Atlanta did not do well" despite use of MARTA, the Metropolitan Atlanta Rapid Transit Authority's rail system, said Marilyn A. Brown, professor of energy policy at the Georgia Institute of Technology and a principal author of the study.

She said Atlanta's "sprawling suburban presence" has led to increased driving that has overwhelmed progress made in rail transport. She also said the relatively low cost of residential energy for Georgians was a disincentive for greater efficiency.

Brown, who was part of a team that shared the Nobel Peace Prize last year with former Vice President Al Gore for its work on global climate change, called the Brookings report "the most comprehensive analysis of the carbon footprint of metropolitan America to date."

She said the authors, who will soon be measuring industrial and commercial carbon emissions as well, hoped that ranking the metros would "promote a virtuous competition that will spur innovative solutions to the climate and energy challenges we face."

Michael Paris, president and CEO of the Council for Quality Growth, an association of developers and industries tied to growth in the Atlanta region, doesn't want to see the government discourage growth.

"We like density and believe there should be plenty of options" for residential neighborhoods, Paris said. "It's really market driven."

The report listed Honolulu as "winning," with its residents averaging 1.36 metric tons of carbon emissions for 2005.

Surprisingly, the second-best metro area was Los Angeles, long thought of as a smog capital. It had a per capita footprint of 1.41 metric tons.

The largest carbon footprint per capita was 3.46 metric tons in Lexington, Ky.

Metro Atlanta residents had a carbon footprint averaging 2.68 metric tons.

The study, titled "Shrinking the Carbon Footprint of Metropolitan America," pointed to areas east of the Mississippi and particularly the Southeast as the most problematic because they have fast growth, low density and fewer mass-transit systems.

"Footprints tend to be smallest in areas with high density and good rail transit," said Brown.

Answering questions about how Los Angeles could have been ranked as the second-best performer, she held that "there's probably a residue of misinformation" about that city. In fact, its urban core is "quite dense and commute links are quite small within much of the L.A. area," Brown said.

The report urged stronger federal action to encourage energy efficiency and research, including some form of carbon tax, a national standard for energy efficiency and efforts to encourage rail transit and more population density.

For example, the report suggests the federal government could require owners to disclose their energy costs when they sell their home.

The report's recommendations could run into resistance, however.

"Whether our carbon footprint could be offset with higher taxes is questionable, said Benita M. Dodd, vice president of the Georgia Public Policy Foundation, a nonpartisan think tank with libertarian leanings.

"There is no consensus as to whether humans have enough of an impact to change global warming," she said.

"I think what we'd end up doing is harming the state's economy with unnecessary regulations and taxes."