In the face of the concern about climate change, environmentally conscious individuals have expressed a growing interest in mitigating their contribution to global carbon emissions, or their ‘carbon footprint.’ The recent proliferation of online emissions calculators developed by a variety of government agencies and non-profit organizations underscores this interest in personal carbon emission reduction (Padgett et al., 2008). Since its inception, the term ‘carbon footprint’ has evoked a wide variety of responses from the general public, policy makers, and the scientific community. This has left many uncertain about what a ‘carbon footprint’ actually is, or how it should be used (Wiedman & Minx, 2007). This confusion is likely due to the lack of consensus on a formal definition and method for calculating the figure.