The trouble with carbon footprint analysis in behavioral climate research

Abstract Everyday behavior of individual citizens plays a central role in reducing global green-house gas emissions and combating climate change. A popular tool to measure and quantify the impact of these behaviors on the climate are so-called carbon footprints (CFPs). In an increasing number of behavioral climate research studies, CFPs are also used as the outcome variable for identifying predictors of sustainable behavior in statistical models. However, many of these studies suffer from confounding potential behavioral predictors with factors already included in the calculation of the to-be-predicted outcome, namely CFPs. To illustrate this issue and its implications, we re-analyzed data from a representative survey of over 10.000 German citizens. Our results imply that the current practice in behavioral climate research of using the same (or highly overlapping) factors for both calculating and predicting CFPs may lead to biased conclusions about the relative importance of predictors of sustainable behavior and, in turn, the development of suboptimal climate change mitigation strategies. We highlight potential pitfalls when dealing with CFPs in behavioral climate research and present future directions and recommendations when analyzing individual sustainable behavior.