Metropolitan areas taking leadership role in reducing carbon emissions.

• Position: News & Numbers

The U.S. carbon footprint is expanding as Americans drive more, build more, consume more energy, and emit more carbon. At the same time, rising energy prices, growing dependence on imported fuels, and accelerating global climate change make the nation's growth patterns unsustainable. Metropolitan America is poised to play a leadership role in addressing these energy and environmental challenges, but federal policy actions are needed to achieve the full potential of metropolitan energy and climate solutions, according to a recent report from the Metropolitan Policy Program at the Brookings Institution.

The report--Shrinking the Carbon Footprint of Metropolitan America, by Marilyn A. Brown, Frank Southworth, and Andrea Sarzynski--quantifies transportation and residential carbon emissions for the 100 largest U.S. metropolitan areas. It concludes that metro area residents have smaller carbon footprints than the average American, although footprints vary widely Metro areas house two-thirds of the nation's population and three-quarters of its economic activity, but they emitted just 56 percent of U.S. carbon emissions from highway transportation and residential buildings in 2005. Residential density and the availability of public transit are important to understanding carbon footprints, as are the carbon intensity of electricity generation, electricity prices, and weather.

Carbon emissions increased more slowly in metropolitan areas than in the rest of the U.S. between 2000 and 2005, according to the study The average per capita footprint of the 100 metro areas grew by 1.1 percent during the five-year period, while the United States partial carbon footprint increased twice as rapidly (by 2.2 percent).While 79 metro areas saw overall growth in their high-way transport and residential carbon emissions during this timeframe, only 53 metro areas increased their footprints on a per capita basis. Carbon emissions from transport and residences declined in...