Carmen Bunzl - Universidad Pontificia Comillas

Chapter 3. Implications of future climate regime architectures 134
would be needed compared to the BAU case to reach different emission
stabilization levels - 450, 550 and 650 ppmv CO2eq. (Höhne, 2006).
Due to the long residence time of CO2 in the atmosphere (in the order of 100
years), the cumulative emissions, irrespective of the time of emission, can be
approximated to define the concentration level. This means that many
alternative pathways are permitted which may have significant differences in
the timing of required emission reductions. Therefore, the spread of emissions
pathways that lead to the same concentration levels can be large. In this context,
emission pathways describe the annual global emission level for some time
period. An emissions corridor is a range of emissions pathways which lead to a
particular stabilization level. The corridor for a 450 ppmv CO2eq. stabilization
level in Figure 1 includes two example pathways: One where global emissions
increase rapidly, peak and then decrease rapidly and one where emissions
decrease moderately from the start. Both paths lead to the same concentration
level - 450 ppmv CO2eq. - by the end of the century.
Figure 3 - 1. Reference emissions and emissions corridor towards stabilization at 450 ppmv CO2 (550
ppmv CO2eq.) (Source: Höhne, 2006)
Escuela Técnica Superior de Ingeniería ICAI Carmen Bunzl Boulet Junio 2008