Ecological Footprint Analysis

Ecological footprint analysis measures human demand on nature by translating the resources a population consumes and the wastes it generates into the area of biologically productive land and sea required to supply them. Introduced by Mathis Wackernagel and William Rees in their 1996 book Our Ecological Footprint, the method expresses both demand (the footprint) and supply (biocapacity) in a common unit, the global hectare, so that the two can be compared directly. When a population's footprint exceeds the biocapacity available to it, the difference is an ecological deficit, and at the planetary scale a persistent deficit signals overshoot of the biosphere's regenerative capacity. The 2002 analysis by Wackernagel and colleagues operationalized this accounting at the global level, estimating that humanity moved from using about 70 percent of the biosphere's capacity in 1961 to roughly 120 percent by the late 1990s. The carbon component, the area of forest needed to sequester fossil-fuel emissions, is typically the largest and fastest-growing share. Footprint analysis is thus a sustainability accounting tool that renders an abstract idea, living within ecological limits, into a single comparable balance sheet.