How suburbs wipe out cities' carbon savings

The environmental benefits of city living were again highlighted this week, as a major new study revealed it is the suburbs that are pushing up the carbon footprint of urban centers.

Researchers long have argued that population-dense cities allow residents to slash their carbon emissions, primarily by reducing reliance on cars and providing relatively energy efficient high-rise properties.

However, a new study from researchers at the University of California has revealed how these emissions savings are being cancelled out by the high carbon footprint of the surrounding suburbs.

The research, which could have major implications for city planners and businesses seeking to cut their greenhouse gas emissions, drew on 37 data points, including energy use, transport use and food consumption, to create an interactive carbon footprint map for more than 31,000 U.S. zip codes.

It found that emissions from transportation meant that suburbs account for around half of U.S. domestic emissions, despite that they account for much less than half the population.

"The average carbon footprint of households living in the center of large, population-dense urban cities is about 50 percent below average, while households in distant suburbs are up to twice the average," the study, which will be published in the journal Environmental Science & Technology, concluded.

For example, the report found that the average household in Manhattan has a carbon footprint of 32 metric tons a year, while the average household in the nearby Great Neck suburb reached 72.5 metric tons a year.

"The goal of the project is to help cities better understand the primary drivers of household carbon footprints in each location," said report co-author Daniel Kammen in a statement. "We hope cities will use this information to begin to create highly tailored climate action plans for their communities."

Kammen said the main lesson for city planners, residents and businesses was to avoid a one-size-fits-all approach to managing emissions from urban centers.

Planners aiming to cut emissions would be forgiven for thinking they should focus on increasing population densities to reduce reliance on transport, but the report indicated that increasing the numbers of people living in urban centers simply can lead to higher emissions in surrounding suburbs.

Report co-author Christopher Jones also warned that increasing population densities in suburbs can prove ineffective because they then "tend to create their own suburbs, which is bad news for the climate."

Kammen advised that cities instead should focus on targeting emissions hot spots and tailoring a range of climate solutions for demographically similar areas; for example, through initiatives aimed to accelerate the roll-out of suitable clean technologies.

"Suburbs are excellent candidates for a combination of solar photovoltaic systems, electric vehicles and energy-efficient technologies," he said. "When you package low-carbon technologies together, you find real financial savings and big social and environmental benefits."

This article originally appeared at Business Green.

City street image by blvdone via Shutterstock.