An evidence-based assessment of online carbon calculators

Online carbon footprint calculators have recently become a popular tool for educating the public about its climate impact. While calculators abound, no standards exist concerning how personal carbon footprints should be determined. As a result, prior studies have concluded that similar input assumptions can yield vastly different results depending on which calculator is used. Previous studies about carbon calculators have compared the modeling methodology used and the resulting footprint calculations. While providing useful insights, this approach does not leverage scholarly studies in order to create an objective yardstick for comparing the calculators. Prior studies also do not provide evidence-based prescriptions concerning how online carbon footprinting practice can be improved. To address the present situation, this study makes two contributions to the literature on carbon footprinting. First, the available evidence-base is synthesized in order to derive a set of 13 principles concerning how personal carbon footprints should be determined. Second, the same principles are used to objectively evaluate 15 commonly used carbon footprint calculators. The findings of the study indicate that carbon footprinting practice lags behind scholarly best-practice prescriptions. This creates an opportunity to use the research findings to improve current practice including driving standardization concerning how carbon footprints are determined. (C) 2013 Elsevier Ltd. All rights reserved.