Carmen Bunzl - Universidad Pontificia Comillas

Chapter 3. Implications of future climate regime architectures 132
compare emission allowances for different future international climate change
regimes; in Ecofys’ study, more approaches - actually most of the ones
presented in Chapter 2 - are assessed. In addition, not two but three levels of
ambition have been explored – they add the much more stringent stabilization
target of 450 ppmv CO2eq.
Höhne et al. use a regional downscaling method that has been criticized in
the literature (van Vuuren et al., 2007; den Elzen et al., 2007). A source of
uncertainty in the analysis, among others, stems from the unknown future
development of emissions. The standard set of future emission scenarios used
as a basis, the IPCC SRES scenarios, are only available at the level of up to 17
regions. They applied the growth rates for 17 world regions on the latest
available data points of the individual countries within the respective regions.
On the level of regions, the full range uncertainty about future emissions is
covered; because when again aggregating the regions, the effect of downscaling
cancels out. Therefore, the assessment presented in this Chapter is valid from
this point of view.
Höhne et al., 2007 also provide a sensitivity analysis for different options to
share emission allowances between Annex I countries. When modeling
emission allowances within groups of countries - e.g. whithin the EU (which
will be discussed in Chapter 4), and therefore focusing on the national level -
the full level of uncertainty is not covered. Höhne et al. use regional growth
rates for individual countries, thus basically using the same trend for all the
countries within a region. In Chapter 4, another study will be chosen – den
Elzen et al. (2007).
However, Höhne et al. do not present abatement costs for the different
approaches to future international climate change agreements. For the purpose
of Section 4, the results obtained with the FAIR model for three different post-
Kyoto climate regimes – the Multistage Approach, the Brazilian Proposal and
Contraction & Convergence – are used (den Elzen et al., 2005).
Escuela Técnica Superior de Ingeniería ICAI Carmen Bunzl Boulet Junio 2008