For the concept of the ecological footprint, some experts believe it is still limited since EF generates a one dimension indicator by concluding complex consumption without proper weighting and aggregation. Which means footprint figure only provides limited reference value instead of a complete and whole sustainability situation.
William E. Rees first introduced this concept in the early 1990s. He develops a framework as an economic assumption named ecological footprint to evaluate a city’s impact on the environment. It is an area unit showing how much bio-productive land and waters are needed within a certain population unit (one person, one city, one country, or all humans) to produce the required resources and absorb the wastes derived under the current technical conditions. Comparing with the area’s biocapacity which refers to the amount of the natural productive supply and finds out whether the region is sustainable (Rees 1992).
When measuring the amount of resource people used to maintain their own survival, there is an inevitable process of conversion allowed various consumption categories to transform into land and water area. Van den Bergh and Verbruggen (1999) criticized that this kind of conversion is evidently inaccurate and incomplete because various categories have been simplified and equalized during that process however it is significant to weight different kind of consumption.
Additionally, Van den Bergh pointed out that ecological footprint’s concept considers more about the ecological principles and thermodynamic laws (Physical weights) but ignore the influence of society and long-term technical potential, for instance like economic growth and market price impact (Social weights). In short, EF does not reflect the future development trend, and the conclusions obtained are instantaneous. (Best Foot Forward 2002).
For example, in the EF program, land use for infrastructure has the same weight as agricultural land use, although the designation of land for road infrastructure is clearly more environmentally destructive than the designated farm (Van den Bergh and Verbruggen 1999).
Therefore, the definition of ecological footprint needs to be further improved and a decomposition type of approach is required to get a logical complete system of multiple complementary indicators.
