Carmen Bunzl - Universidad Pontificia Comillas

Chapter 2. Options for future climate change architectures 60
developed countries. It may also be seen as unrealistic a decision that all
countries participate at once.
2.1.2.3 Common but Differentiated Convergence (CDC)
Description
Common but Differentiated Convergence was presented by Höhne et al.
2006. Annex I countries’ per capita emission allowances converge within, e.g. 40
years (2010 to 2050), to an equal level for all countries. Individual Non-Annex I
countries’ per capita emissions also converge within 40 years to the same level
but delayed, only from the date when their per capita emissions reach a certain
threshold, a particular percentage of the gradually declining global average.
Non-Annex I countries that do not pass this threshold do not have binding
emission reduction commitments. They could either take part in the Clean
Development Mechanism or voluntarily take on no lose emission reduction
targets – emissions allowances may be sold if he target is overachieved, but
none have to be bought if it is not reached.
Implications
Similarly to the Contraction and Convergence approach, the CDC approach
aims at equal per capita allowances in the long term; the main difference is that
it takes into account the historical responsibility of countries. The impact on
Annex I countries may be similar, as they would have to reduce emissions
similarly to C&C, but many Non-Annex I countries would have more time to
develop until they have to start reducing their emissions. Non-Annex I country
participation is conditional to Annex I action – industrialized countries have to
take the lead – as the threshold for participation is a percentage of the global
average. Also, no hot air would occur, no country will receive more allowances
than it would need to satisfy its baseline emissions.
Escuela Técnica Superior de Ingeniería ICAI Carmen Bunzl Boulet Junio 2008