Denser cities yield less air pollution than sprawl

A recent study by National Academy of Sciences and the National Research Council suggests that urban infill, as opposed to urban sprawl, may result in lower carbon dioxide emissions, reports the Forest Grove News-Times.

The study argues that if Americans chose to build up cities, rather than build out, residents would need to drive less, thus reducing their fossil fuel dependency and decreasing overall CO2 emissions by 1-11 percent by 2050. According to the report,  doubling residential density could lower household driving by 5-12 percent. "Compact development" calls for more centralized businesses too -- which means closer-to-home jobs, shopping and activities. The full report also summons the use of alternative modes of transportation in curbing CO2 emissions.

But the committee was at odds over the feasibility of this kind of development, some believing it strays too far from current land-use norms, which favor low-density suburbs. One concern in particular is that state and regional entities would need to have a stronger hand in  controlling development to achieve such results.

With the the transportation sector  accounting for over a quarter of U.S. energy consumption, not to mention a large portion of the country's CO2 emissions,  cities are realizing they must quickly address growing vehicle travel.

At the national level, a bill was introduced in June, in part, by Washington State's Jay Inslee (D-WA), titled the National Transportation Objectives Act. H.R. 2724calls for annual per capita driving reductions, including requiring a 16 percent reduction in driving in the next 20 years.

Portland has already taken a unique approach to this dilemma, writes Christine McFadden of Pamplin Media Group, setting up the nation's first car-sharing service in 1998. Zipcar, as it is now known, allows members to borrow one of 240 cars parked around the city for hourly rates. They believe that for every Zipcar, 15 to 20 privately owned vehicles are replaced, reducing gas usage and carbon emissions. And they offer a model to suit any need: Prius, Toyota pick-up or even a BMW.