Project at a Glance

Title: The Challenge: A Pilot Inter-City Household Carbon Footprint Reduction Competition

Principal Investigator / Author(s): Kammen, Daniel

Contractor: UC Berkeley

Contract Number: 10-325

Research Program Area: Climate Change

Topic Areas: Behavioral Change


This study developed, implemented and evaluated a pilot greenhouse gas reduction competition between eight California cities. The program used techniques common to behavioral interventions, including commitments, goal setting, feedback, local messengers, social networks, persuasive messaging, incentives and competition to recruit and engage households in a yearlong program. Participants earned points for tracking and reducing household energy consumption and motor vehicle emissions, as well as for taking simple one-time actions, like inviting friends, uploading stories and completing a research survey. Participating cities enrolled 2,667 households and logged over 10,000 electricity, natural gas and motor vehicle odometer readings in the online software. Participants entering energy data used about 14% less electricity than a control group, but did not use less natural gas, possibly due to lack of competition deadlines during winter months when opportunities to reduce natural gas are higher, and fewer natural gas end uses for potential reductions. Older and more highly educated participants outperformed younger and less educated participants, while income, political identity and attitudes toward climate change affected participation levels, but not performance. Participants reported very altruistic motivations for joining the program, including improving where they live, protecting the environment and helping organizations they care about. While winning prizes and earning recognition for their city ranked low on a list of reported motivations, participation in the program dramatically spiked only during intense moments of competition. Together, this evidence suggests that inter-city competitions can be a successful strategy to reduce community-wide greenhouse gas emissions.

For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753

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