Common but differentiated convergence (CDC): a new conceptual approach to long-term climate policy |
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| Authors: | Niklas Höhne Michel den Elzen Martin Weiss |
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| Institution: | 1. Ecofys Energy and Environment , Eupener Strasse 59, D-50933, Cologne, Germany;2. Netherlands Environmental Assessment Agency (MNP) , The Netherlands;3. Umweltbundesamt (UBA) , Germany |
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| Abstract: | Abstract This article describes a new concept for an international climate regime for differentiation of future commitments: the ‘common but differentiated convergence’ approach (CDC). Under CDC, Annex-I countries' per-capita emission allowances converge within a convergence period to a low level. Individual non-Annex-I countries' allowances converge to the same level also within the same period (‘common convergence’), but starting when their per-capita emissions are a certain percentage above global average (‘differentiated’). Until then they may voluntarily take on ‘positively binding’ targets. This approach eliminates two concerns often voiced in relation to gradually converging per-capita emissions: (i) advanced developing countries have their commitment to reduce emissions delayed and their targets are not the same as Annex-I countries with equal per-capita emissions; (ii) CDC does not provide excess emission allowances to the least developing countries. Under CDC, stabilizing greenhouse gas concentrations at 550 and 650 ppm CO2-equivalent can be reached with participation at roughly 0% and 50% above global average and convergence to around 3 and 4.5 tCO2-eq/cap within 40 years. Even if the CDC approach is not implemented in its entirety, it is possible that the step-by-step decisions on the international climate regime can be guided by the principles provided in the CDC approach. |
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| Keywords: | United Nations Framework Convention on Climate Change (UNFCCC) Kyoto Protocol International climate policy post-2012 Convergence Per-capita emissions |
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