Authors such as Meadows et al.[i] and Catton[ii] described global carrying capacity overshoot in the 1970s and 1980s in theoretical terms without the ability to adequately measure it. The problem they faced included the sheer size of the exercise on a global scale together with the complication of incalculable amounts of imports and exports of resources and environmental impacts flowing between regions. To combat this challenge, Mathis Wackernagel, and his thesis supervisor William Rees, developed an approach in the early 1990s known as Ecological Footprint analysis[iii] which converted human activity into land requirements with the aim of establishing its ecological impact.[iv]
Ecological Footprint is an inversion of the carrying capacity approach. While carrying capacity assessment begins with a specific landscape and derives a population per area outcome, Ecological Footprint takes a population and estimates a land requirement per person result.[v] Accordingly, it first determines the demands of the population, either at a global or local scale and then calculates the amount of land that this set of lifestyle parameters would require. The land requirement however, could be drawn from anywhere on the planet,[vi] is consequently usually measured in global hectares, and illustrates the condition of ecological overshoot when exceeding the actual land available. Given the globalised nature of modern trade, proponents of this approach argue that Ecological Footprint analysis is thus an accurate representation of existing circumstances.[vii]
Global Footprint Network’s online Footprint Calculator. The user takes on an avatar who inhabits a suburban scene which is progressively illustrated while lifestyle choices are made. Then, at the end of the process, the user is informed of their global footprint and the proportion of land-uses required such as land for food, shelter, mobility, goods and services.
