Cutting Household Carbon Footprints

Many U.S. residents want to take action to rein in carbon dioxide emissions but aren't sure where to focus their attention. Now two researchers have calculated carbon footprints for models of over 2000 typical U.S. households, to help people tailor their carbon-cutting actions to their lifestyles (Environ. Sci. Technol., DOI: 10.1021/es102221h).

Doctoral student Christopher Jones and his advisor, Dan Kammen, of the University of California, Berkeley, used life cycle assessment to calculate the greenhouse gas emissions embodied in the activities of daily life, such as transportation, energy use, and diet. They produced comprehensive carbon footprints for model households by applying the results of their life cycle assessments to 28 metropolitan areas.

How best to shrink carbon footprints varied dramatically by location, income, and household size, Jones says. For people in Los Angeles, altering transportation behaviors would be more effective for curbing emissions than cutting home energy use would be. That's because people there drive a lot, while utilities already generate about half the region's electricity using relatively low-emission sources like hydropower, nuclear, and natural gas. Meanwhile, households in Minneapolis could focus on insulating their houses to decrease their footprints. Residents there already tend to use public transportation but rely heavily on heating during the winter.

Jones and Kammen have created an online tool that allows users to get advice on the most effective carbon-curbing actions. But because the data are limited to the study's 28 metropolitan areas, the duo wants to refine them to the neighborhood level.