Page 310 - Materials Chemistry, Second Edition

294 4 Life Cycle Impact Assessment

Regarding the evaluation of land use there are different approaches in
LCA. The scientific discussion is among other things concerned with how to
ecologically evaluate a given land use.
The impact categories human and ecotoxicity are also among the ‘standard
categories’ of LCA. Here too, different approaches are used for a consid-
eration within the impact assessment. Points of criticism vary to an extent
where no direct harmonisation is expected in the near future. 371) Besides,
there are even problems at the level of the inventory, for example, incomplete
inventory data, which in the end can infer misinterpretations. Human and
ecotoxicity have for these reasons not been evaluated in the context of the
impact assessment of this study.

In the example study the assignment of inventory parameters to the selected
impact categories and the respective impact indicator models are already repre-
sented in the phase ‘definition of goal and scope’ (see Table 2.1).
In the supplement of the example study, the reasons for the selection of impact
indicators as well as the indicator models as basis for the impact assessment are
described in more detail. For every one of the selected impact categories equivalence
factors of the selected indicator model for all assigned inventory parameters are
presented in a table. There are impact categories like, for example, ‘Greenhouse
effect’ 372) for which a detailed presentation in every LCA seems to almost be
exaggerated because of an existing consent with respect to the indicator model.
Other impact categories on the other hand are discussed in scientific literature (e.g.
photo-oxidant formation) with their controversies, and the indicator model selected
for the special study must be transparent and comprehensibly described.

4.6.1.1 (Greenhouse) Global Warming Potential

The greenhouse effect (global warming and climate change) as impact
category is the negative environmental effect of heating of the terrestrial
atmosphere caused by anthropogenic activity. It has already been described in
detail in the appropriate references. 367) The most frequently applied indicator
so far in LCAs is the radiative forcing 368) and is indicated as CO -equivalent
2
value (GWP). The characterisation method is generally accepted.
Substances and their CO -equivalence values, which can be found in
2
calculations of the greenhouse potential as ‘global warming potential (GWP)’,
are listed in Table 4.17:

371) This LCA study was performed in 2006.
372) Now called climate change.
373) IPCC (1995a, 2001).
374) CML (1992) and Kl¨ opffer 1995