Page 258 - Materials Chemistry, Second Edition

242 4 Life Cycle Impact Assessment

strongly acid aerosol particles at the extremely low temperatures of the Antarctic
stratosphere play an important part in mechanisms of reactions of the catalytic
ozone depletion. As the Arctic stratosphere does not have such a deep cooling down
potential compared to the Antarctic, the effect is less retractable but nevertheless
measurable: in the Antarctic – and to a lesser extent – in the Arctic spring, there is
a strong decrease of stratospheric ozone concentration depicted as the ‘ozone hole’.
Inspite of a measurable increase of ozone concentration in the course of the year,
annually measured minimum concentrations have decreased. Measurements also
show the decrease in the stratospheric ozone concentration in non-polar regions
based on the impact of homogeneous catalysis predicted by Roland and Molina. 189)
This decrease is less dramatic than the ozone holes, but continuous.
The discovery of the ‘ozone hole’ certainly accelerated the international political
agreement under the patronage of the UN, particularly with regard to concrete mea-
sures (a Principle Declaration the ‘Vienna Convention’ dates before the discovery
of the ozone hole):
• Vienna Convention for the protection of the ozone layer dated March 22, 1985
(‘Vienna Convention’; Discovery of the ozone hole in autumn 1985).
• Montreal Protocol dated September 16, 1987 on substances inducing the decay
of the ozone layer. 190)
Within an amazingly short period of time concrete lists and schedules for the
production phase-out of substances causing the ozone depletion was provided. At
the same time the development of chlorine free substitutes began for special areas
of CFC applications. Unfortunately some of these substitutes are identical to those
causing the greenhouse effect 191) (Table 4.9) resulting in counter-productive effects.
Both the interim report of the Enqu` ete Commission as well as a statement by
Rowland 192) showed the surprise following the emergence of the ozone hole that
had not been predicted. This dramatically exemplifies that highly complex systems
like the stratosphere are far from offering themselves to a complete computation.
Unpredictabilities are always possible and therefore the precautionary principle is
to be taken seriously, to act before full scientific evidence on an environmental
damaging impact is provided. With a minimum concentration decrease the ozone
hole continues to grow which has been verified by measurements. It now extends
far beyond the continent 193) although the most important substances responsible for
the ozone hole have been internationally banned for years causing a slow decrease
of their concentration in the atmosphere.

4.5.2.3.3 Impact Indicator and Characterisation Factors The impact indicator for
the category ‘stratospheric ozone depletion’ is the formation of chlorine (and

189) Rowland and Molina (1975) and Dameris et al. (2007).
190) Deutscher Bundestag (1988).
191) IPCC (1995a), Kl¨ opffer and Meilinger (2001a) and IPCC/TEAP (2007).
192) Deutscher Bundestag (1988) and Rowland (1994).
193) Dameris et al. (2007).