Understanding the environment: Problems with the way we think
Understanding the environment: Problems with the way we think

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Understanding the environment: Problems with the way we think

2.7 Ecological footprinting

How do we practically re-engage with the world and breakaway from the confines of reductionist thinking? Since we are both part of the problem and part of the solution, we need to start collecting information on how our personal system impacts on the ecological systems that surround us. The ecological footprinting technique is probably the simplest and most straightforward approach for kicking off our observations.

The ecological footprinting technique was first proposed by Mathis Wackernagel and Bill Rees (Wackernagel and Rees, 1996) to estimate the total land area that would be needed by a family unit, a city or nation to sustain itself and to absorb its wastes. The calculations result in a land area figure which can act as an index of sustainability. For example, a nation that consumes more resources and produces more wastes than can be accommodated by its land area is clearly unsustainable.

A useful example to illustrate how this technique works is to look at the Biosphere 2 experiment (Figure 3.5). In 1989, a 1.27 hectare structure was built in Arizona, USA, with the idea of creating a living system that was materially closed from the outside world. In other words, all the components needed to maintain life processes were sealed within the structure. This had to include the photosynthetic plants for producing the food and oxygen, and the animals for consuming the food and producing carbon dioxide. In essence, the wastes of one organism were the nutrients of other organisms, in an unending cycle of matter. The living system was energetically open, with sunlight able to enter the structure through glass windows. On 26 September, 1991, eight people were locked inside the facility and managed to survive for two entire years within the structure, although oxygen had to be pumped in from the outside at the end of the first year, ending the materially closed system experiment, but they went on to live in the biosphere for a further year. In effect, the individuals in the Biosphere 2 experiment had to survive on an ecological footprint of 0.16 hectares each, on what was essentially a pre-industrial lifestyle. The cost of attempting to recreate a self-sustaining closed system exceeded US$200 million.

Figure 3.5
Figure 3.5 Biosphere2: a system with energy entering and leaving, but matter circulating between animals and plants as a closed loop (© Biosphere 2)

The ecological footprinting technique takes the same closed systems approach. Basically, if you had to be enclosed within a structure similar to that of Biosphere 2, how big would it need to be to maintain your current lifestyle? The same 'bubble' concept can be used to calculate the area that some institutions, such as schools, would need to maintain themselves. For example, a study of a school in the Isle of Wight, UK, showed an ecological footprint of 150 hectares while it occupied only 7.3 hectares of land. Similar calculations can be carried out for cities. London was shown to have an ecological footprint almost equivalent to the whole area of the UK, although the figure of 20 million hectares was revised downwards in a later calculation. Wackernagel and his colleagues also carried out a study of 55 nations to estimate their ecological footprint for the year 1995. The average ecological footprints (hectares per person) varied from 0.6 for Bangladesh citizens to 9.6 for citizens of the USA. But more significantly, the 'ecological deficit' of each nation, i.e. the average ecological footprint minus the average biocapacity (area of biologically productive land and water required to produce the necessary resources and absorb the resulting waste), was calculated. Once again, the USA was one of the worst offenders, with an ecological deficit of -4.1 hectares per person, while countries such as New Zealand showed much healthier figures of 9.4.

Figures calculated in 2003 show that there is a global ecological deficit of -0.4 hectares per person (Living Planet Report, 2006).


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