The ecological footprint was originally conceived as a simple and elegant method for comparing the sustainability of resource use among different populations, and has since considerably enriched the sustainability debate. Since the formulation of the ecological footprint, a number of researchers have mentioned the oversimplification in ecological footprints of the complex task of measuring sustainability of consumption. In particular, aggregated forms of the final ecological footprint make it difficult to understand the specific reasons for the unsustainability of the consumption of a given population, and to formulate appropriate policy responses. In response to the issues highlighted, the Ecological Footprint has undergone significant modification. Comprehensive input-output-based ecological footprints are now calculated in many countries, and applied to populations, companies, cities, regions and nations.
