An interesting new study, Chakravarty, Shoibal, Ananth Chikkatur, Heleen de Coninck, Stephen Pacala, Robert Socolow, and Massimo Tavoni. “Sharing Global CO2 Emission Reductions Among One Billion High Emitters.” Proceedings of the National Academy of Sciences of the United States of America (July 6, 2009) could be an excellent reading for students in helping them determine what might constitute equitable, and politically viable, post-2012 regimes. The study advances the thesis that the concept of “common but differentiated responsibilities” should be construed from the perspective of the emissions of individuals instead of nations. The study establishes a cap on emissions based on a floor of 1 tCO2/yr, and then calculates national budgets based on the number of “high emitter” individuals in each country, and their aggregate emissions. The authors conclude that the formula achieves equity and fairness in climate change policy in the sense that: 1. countries with a large proportion of high emitters are required to do more; and 2. countries with similar emission profiles would have similar commitments.
Applying the formula, the study concludes that the United States and China would have the highest carbon dioxide abatement assignments, while India, already, or poised to be, the third largest emitter of greenhouse gas emissions, would largely get a “free pass.” Interestingly, the formula would impose fairly substantial commitments on Africa, due to high carbon intensity and inequality in South Africa and in North African nations with energy industries. Russia and the Middle East would also take on substantial assignments for the same reason. A similar approach is taken by the think-tank EcoEquity in its formulation of a Greenhouse Development Rights scheme, though differences between its approach and that of the proposal of Chakravarty, et al. on issues such as historical emissions, can help the students to grapple with the large number of considerations that are pertinent to formulating long-term climate change commitments.