Resources

In the EI99 model, damage to resource stock is represented as a lowering of the concentration of those resources in the earth's crust. (Generally, in metals and minerals, the ores with the highest concentration of the target material are exploited first.) Each time a mineral resource is used, the average concentration of the remaining resource is reduced. For fossil fuels, the concentration of resources is not as important as the ease of extraction. The damage to fossil fuel reserves is calculated in the EI99 by estimating the additional energy required to extract energy reserves at some arbitrary point in the future. There are some problems with this approach, mainly in determining an appropriate point in the future from which to compare present extraction energy, and the problem of dealing with the substitution of one fuel for another. Nevertheless, this does represent a meaningful relationship between the use of the resource and the future consequences of this use.

Figure 3

If we were to adapt this resource impact method for Australia, very little work would be required, as it is based on global rather than local reserves. Having said this, the unique position of Australia having extensive coal-based energy reserves places us in a different political context which may affect the way fossil fuels are weighted by any expert panel.

Damage to human health

EI99 has five impact categories, which are related to human health:

• climate change (diseases and displacement.)

• ozone layer depletion (cancer and cataracts)

• ionizing. radiation (cancer cases and type)

• respiratory effects (cases and type)

• carcinogenesis (cancer cases and type)

Climate change and ozone layer depletion are modeled as global effects and are therefore more easily translated into the Australian context. The other three categories are modeled as if all the releases are within the European environment. Therefore, European background concentrations and population exposures are used. Work on these three categories would need to be taken back to first principles and modeled specifically for Australia.

Ecosystem quality

Two measures are used for ecosystem quality in EI99. For toxicity effects, a measure of the 'potentially affected fraction' of species is used as an indicator of toxic stress. This is applied mostly to lower order organisms that live in water and soil, such as fish, crustaceans, algae, worms, nematodes, micro-organisms and several plant species. 'The PAF can be interpreted as the fraction of species that is exposed to a concentration equal to or higher than the No Observed Effect Concentration (NOEC). It is a measure for toxic stress, and in fact not a real damage.'.

The second measure, applied to vascular plants to model the effects of acidification, eutrophication and land use, is the PDF ('potentially disappeared fraction') of species. 'The PDF is used to express the effects on vascular plant populations in an area. The PDF can be interpreted as the fraction of species that has a high probability of no occurrence in a region due to unfavorable conditions.'

Effects on higher animals are not modeled due to the complexity of pathways and effects, and it is assumed that the modelling of the lower order organisms and vascular plants should be a reasonable indicator of health of higher order species.

These two measures provide the basis on which to begin to model the Australian environment. The damage pathways will be very different in Australia to Europe, but the basic principles should still hold. Stresses related to water flow, land clearance and salinity would need to be included here for vascular plants. For the PAF from toxic releases, we would need to examine the location of the majority of toxic releases and to examine the properties of the receiving environments. This would be one of the most difficult exercise of the entire project due to deficiencies in the data.