Page 208 - Materials Chemistry, Second Edition

194 R.K. Rosenbaum et al.

• Existence of impact thresholds—in the characterisation modelling we typically
assume linear cause–effect relationships for the small interventions in the pro-
duct system, but in the full environmental scale, there may be impact levels that
represent tipping points beyond which much more problematic effects occur.
• If so, then how far are we from such critical impact levels—is this an important
concern in the near future?
• Severity of effect and gravity of consequences—disability, death, local extinc-
tion, global extinction
• Geographical scale
• Population density is essential for the impacts on human health.
• Possibility to compensate/adapt to impact
• Temporal aspects of consequences—when will we feel the consequences, and
for how long?
• Is the mechanism reversible, can we return to current conditions if we stop the
impacts?

Indeed, many of these science-based criteria are attempted to be included in the
environmental modelling linking midpoint indicators to endpoint indicators, and
midpoint-to-endpoint characterisation factors may thus be seen as science-based
weighting factors for the midpoint impact categories.
Different principles applied to derive weighting factors are:

• Social assessment of the damages (expressed in financial terms like willingness
to pay), e.g. impact on human health based on the cost that society is prepared to
pay for healthcare (e.g. used in EPS and LIME LCIA methods)
• Prevention costs (to prevent or remedy the impact through technical means), e.g.
the higher the costs, the higher the weighting of the impact
• Energy consumption (to prevent or remedy the impact through technical means),
e.g. the higher the energy consumption, the higher the weighting of the impact
• Expert panel or stakeholder assessment, e.g. weight attributed based on the
relative significance, from a scientific perspective (subjective to each expert), of
the different impact categories
• Distance-to-target (politically or scientifically defined): degree at which the
targeted impact level is reached (distance from the target value), the greater the
distance, the more weight is assigned to the impact (e.g. used in EDIP,
Ecopoints and Swiss Ecoscarcity LCIA methods).
• Social science-based perspectives, not representing the choices of a specific
individual, but regrouping typical combinations of ethical values and prefer-
ences present in society into a few, internally consistent profiles (e.g. used in
ReCiPe and Ecoindicator99 LCIA methods).
The latter approach is relatively widely used and applies three cultural per-
spectives, the Hierarchist, the Individualist and the Egalitarian (a forth perspective,
the Fatalist is not developed for use in LCA since the fatalist is expected not to be
represented among decision-makers, targeted by an LCA). For each cultural per-
spective coherent choices are described in Table 10.2 for some of the central