City dwellers produce less carbon, report suggests

While cities are hot spots for global warming, people living in them turn out to be greener than their country cousins.

Each resident of the largest 100 largest metropolitans areas is responsible on average for 2.47 tons of carbon dioxide in energy consumption each year, 14 percent below the 2.87 ton U.S. average, researchers at the Brookings Institution say in a report being released Thursday.

Those 100 cities still account for 56 percent of the nation's carbon dioxide pollution. But their greater use of mass transit and population density reduce the per person average. "It was a surprise the extent to which emissions per capita are lower," Marilyn Brown, a professor of energy policy at the Georgia Institute of Technology and co-author of the report, said in an interview.

Metropolitan area emissions of carbon dioxide are highest in the eastern U.S., where people rely heavily on coal for electricity, the researchers found. They are lower in the West, where weather is more favorable and where electricity and motor fuel prices have been higher. The study examined sources and use of residential electricity, home heating and cooling, and transportation in 2005 in the largest 100 metropolitan areas where two-thirds of the people in the U.S. live. It attributed a wide disparity among the 100 cities to population density, availability of mass transit and weather.

Lexington, Kentucky, had the biggest per capita carbon footprint: Each resident on average accounted for 3.81 tons of carbon dioxide in their energy usage. At the other end of the scale was Honolulu, at 1.5 tons per person.

Click here to read the full CNN article.