Constraining equitable allocations of tradable greenhouse gases emission quotas by acceptability

Allocations of tradable greenhouse gases (GHG) emission quotas among countries may take place according to several sharing rules corresponding to a certain perception of equity. For instance, allocating quotas in direct proportion to population, in inverse relation to GDP or according to past emissions has been advocated. Taking a long term perspective, we compute such allocations of tradable quotas with a dynamic model developped on the basis of the RICE model (Norhaus and Yang, 1996). The total amount of quotas to be distributed in each period corresponds to the total optimal amount of emissions to be realised at each period. We observe that the "equitable" quotas allocation rules the most often referred to are not acceptable by every country at every period: some of them would be better off by not co-operating. We then propose a mechanism which determines allocations of GHG emission quotas that satisfy as much as possible each "equitable" allocation rule while keeping acceptability for each country.