Evaluating the Use of a Carbon Footprint Calculator: Communicating Impacts of Consumption at Household Level and Exploring Mitigation Options

Through an increasingly globalized supply chain, local consumption of goods and services has impacts around the world. The carbon footprint can be used to link local consumption to global greenhouse gas emissions. This study describes the development and use of REAP Petite, a household-level footprint calculator. We describe how the tool integrates geodemographic information with user-inputted data; allows users to compare their footprint with others in their community; and presents them with targeted pledges to help them reduce their impact. Such tools can help individuals to see the impact their consumption has on emissions and help promote alternative behaviors. Based on the lessons learned during tool development and through using the tool with individuals in the UK and Sweden, we make recommendations for the development of new footprinting tools for use in the public domain. We highlight the benefits of using bottom-up methods for calculating footprints; recommend that designers consider future-proofing their tools; discuss the trade-off between complexity and usability; and recommend that designers consider going “beyond carbon” to increase the appeal of tools to a wider audience. We also highlight the importance of providing opportunity for users to compare their footprints with those of others and of monitoring and evaluating user engagement with the tool.