America's carbon footprint is expanding. With a growing population and an expanding economy, America's settlement area is widening, and as it does, Americans are driving more, building more, consuming more energy, and emitting more carbon. A new study by the Metropolitan Policy Program at the Brookings Institution ranked the per capita carbon footprint of the 100 largest metropolitan areas in the U.S. The six metropolitan areas centered in Pennsylvania landed across the spectrum. Lancaster and Philadelphia led Pennsylvania with rankings of 23 and 27 respectively. Harrisburg finished a distant last with a ranking of 92.  

Metropolitan areas with high population density and well developed public transportation systems, such as Philadelphia, fared well in the study.

The analysis combined the carbon emissions from both transportation and residential energy use. Transportation carbon emissions were calculated as a combination of auto and truck emissions. Residential emissions were based on both electricity use and the use of other residential fuels for home heating. Power plant type used to source electricity determined the emissions for that category.  

Metropolitan areas with high population density and well-developed public transportation systems, such as Philadelphia, fared well in the study. Many California cities were ranked near the top because of their fair climates and the availability electricity from renewable energy sources. Because most of Pennsylvania's electricity is generated by burning coal, none of Pennsylvania's metropolitan areas have low carbon footprints for residential energy use. For coverage of the study in Philadelphia, please click here.  

Harrisburg's large carbon footprint was driven by truck and auto transportation emissions. While Harrisburg's development pattern has favored transportation by automobile, the study's methodology may be skewing the results negatively for the residents of the Harrisburg metro area. The transportation carbon emissions were calculated based on the vehicle miles traveled within a metropolitan area, not the actual miles traveled by the residents of that metropolitan area. With a large highway systems and trucking industry, many of those vehicle miles traveled are from the movement of goods and people across the region, rather than within. For coverage of the study in Harrisburg, please click here.  

For a summary of the Brookings Institution report, please click here.