This chapter focuses on the Ecological Footprint, largely because it is much broader than the carbon footprint and raises a number of interesting points regarding its calculation. The notion of a ‘footprint’ representing an impact is probably as old as the human race. The carbon footprint is important in terms of climate change and has received much political and media attention, although arguably nowhere near enough. The Ecological Footprint (EF) was developed in the early 1990s by the academics William Rees and Mathis Wackernagel. The EF employs an assumed ‘biological equivalence’ for the different land-use categories and is a way of redefining the Earth’s surface in terms of its productivity, that is defining it in terms of producing biomass for the benefit of humans; be it for food, forest products or absorption of carbon. A country that exports almost all that it produces will have a relatively low EF for consumption although the EF for production may be high.