The ecological footprint from a systems perspective of sustainability

The Ecological Footprint (EF) is a method for estimating the biologically p roductive area necessary to support current consumption patterns, given pre vailing technical and economic processes. By comparing human impact with th e planet's limited bioproductive area, this method tests a basic ecological condition for sustainability. The ecological footprint has gained populari ty for its pedagogical strength as it expresses the results of its analysis in spatial units that can easily be communicated. Many EF estimates have b een performed on a global, national and sub-national level. In this paper, we review the method and critically assess it from a sustainability perspec tive based on first order principles. We examine: Which aspects of sustainability are already covered by existing EF assessme nts; Which further aspects of sustainability could be made accountable through t he EF (such as areas needed to assimilate waste streams that are not yet ac counted for in present assessments); and Those aspects of sustainability that cannot be accountable through the EF, thereby needing complimentary auditing tools. Since the EF is a measure of renewable biocapacity, we argue that some dime nsions of ecological sustainability should not be included in the EF. These include human activities that should be phased out to obtain sustainabilit y, such as emissions of persistent compounds foreign to nature and qualitat ive aspects that represent secondary uses of ecological areas and do not, t herefore, occupy a clearly identifiable additional ecological space. We als o conclude that the EF is useful for documenting the overall human use or a buse of the potentially renewable functions and services of nature. Particu larly, by aggregating in a consistent way a variety of human impacts, it ca n effectively identify the scale of the human economy by comparison with th e size of the biosphere.