J E R O E N V A N D E N B E R G H *
Universitat Aut`onoma de Barcelona & ICREA, Spain VU University Amsterdam, the Netherlands
F A B I O G R A Z I *
International Research Centre on the Environment and Development, CIRED, ENPC/ParisTech & EHESS/CNRS, France
Searching for indicators of sustainability is a recurrent theme in environmental science and policy. The “ecological footprint” (EF) has emerged as a popular concept and method for measuring sustainability (1). For example, ISI web of knowledge delivers over 500 journal articles for “ecological footprint”swith an increasing trend from 2001 to 2008s while Google delivers more than 2 million and Google Scholar more than 14,000 hits for “ecological footprint”. This is partly due to the online “Footprint Network” putting much effort in diffusing the EF method.
The EF converts the flows of energy and matter to a specific economy or activity into corresponding land area needed to support these flows, using seven land use categories. The outcome, expressed in area units, is suggested to capture use of biologically productive land (and water) to generate resources and absorb wastes. Footprints can be calculated for individuals, activities, technologies and spatial units –cities, regions, countries or the world as a whole. In addition, the method entails the calculation of an “ecological deficit” of a region or country, equal to the difference between its ecological footprint and its available ecological capacity. Countries can then be ranked on the basis of a total or per capita footprint, while they can be judged as (un)sustainable
if the ecological deficit is negative (positive). The footprint approach has given rise to the related notions of energy, carbon, and water footprints, with an explosion of studies devoted to the latter.
Is it useful to spend so much intellectual energy, time, and research money on EF studies? We believe not. The quantitative EF method suffers from a number of shortcomings, which cause it to be a weak, even unreliable, tool for public policy, despite all good intentions of its inventors and users. Many of them seem to be unaware of its methodological shortcomings as identified by various economists and environmental scientists (2). A recent assessment of imperfections of the method by the most important EF proponents (3) identifies 26 minor shortcomings but surprisingly neglects the most important defects identified in earlier publications.
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