What is 'footprint' in Antarctica: proposing a set of definitions

Footprint has become a common term in environmental research in Antarctica, yet after 25 years there is still no certainty about what it refers to. In relation to Antarctica, the closest definition has been 'the spatial extent and intensity of disturbance'. Yet there is still confusion around what a 'disturbance' footprint is actually measuring. This is evident within Committee for Environmental Protection documents, in which there have been over 80 mentions of footprint, with at least eight different meanings, since 1998. To improve clarity in its use by both scientists and policymakers, we first examine the development of the term footprint, how it has been applied, and its usefulness in applications such as interpreting 'minor or transitory' activities. We then identify and define a suite of footprint types (disturbance, building, contamination, non-native species, noise, visual, visitation, risk, carbon, ecological, and human), with the aim of developing a common understanding of what the term refers to. Our goal is to ensure the concept of footprint can be a useful environmental tool to facilitate progressing environmental protection.