In the context of the negotiations for apportionment of emission reduction post‐Kyoto regime, issues of equity and fairness have emerged. The purpose of this paper is to generate a model for equitable emission reduction apportionment.
The mathematical model has been designed utilizing mitigation capacity (based on gross domestic product (GDP)) and cumulative excess emissions as the criteria for apportionment. Quantitative results have been arrived at, using cumulative γ and parabolic mitigation emission reduction trajectories to demonstrate the impact on stakeholders.
The apportionment outcomes are independent of the specific trajectory fine‐tuned in the feasibility region. Since the apportionment takes into account entitlements and the mitigation capacity, Africa and India have negligible reduction targets in tune with the development goals in these economies. Substantial reduction commitments would fall on the USA and the EU countries. China gets a moderate target due to higher emissions and GDP.
The approach is in consonance with the principle of common but differentiated responsibility enunciated in the UNFCCC and the Kyoto Protocol. The method can easily incorporate emissions trading. The issue of population as a driving factor of emissions has been partially accounted for by considering the entire national GDP as an emission reduction responsibility factor, without considering population based GDP entitlements.
The generalized framework can be extended to situations involving responsibility apportionment in public policies dealing with externalities. The framework is original and will be useful to policymakers and other stakeholders dealing with climate change, as well as researchers looking at externalities of a global or national dimension.
