The ecological footprint concept was conceived by Wackernagel and developed by Wackernagel and Rees to estimate how much biologically productive space people use to sustain themselves. Ecological footprint calculations are based on two assumptions: first, it is possible to keep track of most of the wastes we generate; secondly, most of these resource and waste flows can be converted to a corresponding biologically productive area. Thus, ecological footprint of any defined population (from a single individual to a whole city or country) is the total area of biologically productive land and water occupied exclusively to produce all the resources consumed and to assimilate all the wastes generated by that population, using prevailing technology. Ecological footprinting takes into account arable land separated into cropland, pasture land, and forest.
Thus, ecological footprints give a direct comparison between nations regarding the level and patterns of consumption of their citizens. Just as important as the level of consumption is the ecological space which the nation has available. This determines how many people a nation can support at the current lifestyle without, on balance, appropriating ecological space from other nations. The ecological footprinting, for very pragmatic reason, should meet the following criteria: (1) the calculation procedure should be objective and scientifically sound, (2) indicators should have a clear interpretation and be understandable by non-scientists, (3) indicators should relate to clear policy objectives.
In the paper we present ecological footprint estimates made for the Polish nation within its border over 1955Ś1997. In this approach we managed to reach numbers comparable with other countries' studies. It appears that Polish footprints do not differ very much from western developed societies. However, as usual in dynamic economies, they seemto be too large when compared to available ecological space.
The ecological footprint is one attempt at developing a biologically based ecological economics, which approximates reality better than many economic expansionist models. There are several advantages and limitations associated with the development of the ecological footprint concept. The major advantage of the ecological footprint concept over some other indicators like environmental space is that the former concept gives a clear, unambiguous message often in an easily digested form. The clarity of the message is an important function of any indicator for both policy makers and the general public. Next, the calculation upon which the ecological footprint is based is relatively easy to undertake and much of the data is available at different spatial scales. Nevertheless, the presentation of ecological footprinting needs to be greatly improved. Ecological footprint is a static measure, it ignores technological change, it ignores underground resources, it is a stock measure and does not measure flows, it lacks measures of equity. The energy footprint aspect needs to be tackled by experts in the energy field. More work needs to be done on the vexed question of forest yield factors and sustainability. But despite of the many problems, there remains tremendous potential in the use of ecological footprints for estimating how many people each nation can support in a specified consumption and production patterns.
