In his column in yesterday’s Boston Globe, Harvard economics professor Edward Glaeser illustrates that densely developed cities are better for the environment than leafy suburbs. The column correctly states that the average household in Boston’s urban core emits significantly fewer pounds of carbon dioxide per year, in part because people in the city drive less. Unfortunately, the column also states that public transportation “does little to balance the scales”— a statement that could easily be misinterpreted to mean that the use of public transit does little to decrease carbon emissions. In fact, Glaeser’s research that formed the basis for his conclusions indicates that although city dwellers tend to use more public transportation than suburbanites, their carbon footprint is still significantly lower precisely because the emissions from transit are modest relative to the contributions of cars. Travel by public transportation emits about half as much carbon dioxide per passenger mile than private vehicles, and uses about half the fuel.
Glaeser’s message is clear. If we’re going to minimize our carbon footprint, we need to not only support denser development in downtown Boston, but also greater investment in our underfunded public transportation system.