Page 250 - Materials Chemistry, Second Edition

234 4 Life Cycle Impact Assessment

• Quantification has to be done at the starting point of the impact hierarchy
for global categories because only based on these, can relatively secure model
calculations be accomplished (these are typical mid-point categories).
For these reasons global impact categories are considered to be of greater objectivity
than others. 163) As for regional impact categories there are requirements for a
stronger consideration of geographical release, distribution, and impact modes
even if this implies higher requirements in the inventory. 164) .

4.5.2.2 Climate Change

The waves of heat speed from our earth through the atmosphere towards space.
These waves dash in their passage against the atoms of oxygen and nitrogen, and
against the molecules of aqueous vapour. Thinly scattered as these latter are, we
might naturally think meanly of them, as barriers to the waves of heat.
(John Tyndall 1863.) 165)
There is worldwide a broad consensus on the impact category climate change
and its quantification. However, characterisation factors slightly change with time
as shown in reports published by the IPCC (Intergovernmental Panel on Climate
Change) 166) , especially owing to varying knowledge and subsequent assessments of
indirect impacts. This is a common scientific process: we thereby apprehend that
science approaches ‘truth’ at best, without ever, according to Popper, 167) reaching it.
The following can be learned from the category climate change for development
of methods in LCIA:
• Quantification of the selected indicator in a form suited for LCA, here as GWP;
• Deduction of scientific relations including equivalence factors in specialised
disciplines;
• Thorough scrutinising of the methods by an international Peer Review;
• Publication of results on behalf of a respected scientific committee (IPCC), which
is accountable to the United Nations only.

To the first point: this turned out by chance, because usability of the GWP for
LCIA was surely the last thing the IPCC was concerned about. To the second:
LCA practitioners are often generalists and should delegate an elaboration of
indicators plus quantification to specialists. Unfortunately their proposals are often
unfeasible because they are usually not familiar with the LCA methodology. 168) The

163) Owens (1996, 1998).
164) Potting and Hauschild (1997a,b), Owens (1997), Bare, Pennington and Udo de Haes (1999) and
Potting et al. (2001, 2002).
165) Tyndall (1873). (first edition 1863; the discovery of the natural greenhouse effect by Tyndall dates
back to 1859 after predictions by Joseph Fourier 1824 and Claude Pouillet 1827).
166) IPCC (1990, 1992, 1995a, 2001, 2007).
167) Popper (1934).
168) Fava et al. (1993).