The Ecological Footprint (EF) is a method for estimating the biologically productive area
necessary to support current consumption patterns, given prevailing technical and
economic processes. By allowing to compare human impact to the planet's limited
bioproductive area, this method tests a basic ecological condition for sustainability. The
ecological footprint has gained popularity for its pedagogical strength as it expresses the
results of its analysis in spatial units that can easily be communicated. Many EF estimates
have been performed on a global, national and sub-national level. In this paper, we
review the method and critically assess it from a sustainability perspective based on first
order principles. We examine:

• which aspects of sustainability are already covered by existing EF assessments;

• which further aspects of sustainability could be made accountable through the EF
(such as areas needed to assimilate waste streams that are not yet accounted 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 dimensions of
ecological sustainability should not be included in the EF. These include human activities
that should be phased out to obtain sustainability, such as emissions of persistent
compounds foreign to nature and qualitative aspects that represent secondary uses of
ecological areas and do therefore not occupy a clearly identifiable additional ecological
space. We also conclude that the EF is useful for documenting the overall human use or
abuse of the potentially renewable functions and services of nature. Particularly, by
aggregating in a consistent way a variety of human impacts, it can effectively identify the
scale of the human economy in comparison to the size of the biosphere.