Differentiated or Uniform International
Carbon Taxes: Theoretical Evidences and
From the late 1980s to 1996, debates on economic incentives aiming at curbing greenhouse gas emissions focused on a uniform international carbon tax. There are many historical reasons why attempts to coordinate climate policies through price signal failed and why coordination through quantitative emission limits was adopted at CPO3 (3rd Conference of the Parties, Kyoto 1997). The latter framework, however, is not firmly established as long as the following question is unresolved: which rules should be adopted for the distribution of primary rights to developing countries? If no politically acceptable rule can be found, the negotiation agenda may see the return of coordination through prices or some hybrid system. This paper aims at shedding light on the difficulties inherent to the price approach, some of which in fact are comparable with those impinging on quota-based coordination. Relying on a theoretical model that captures the key practical aspects of climate policies, this chapter demonstrates that an efficient allocation is achieved by differentiated taxes. Beyond existing uneven distribution of income, this is due to country-specific side effects of a carbon tax and specifics of development patterns. A uniform tax would be appropriate only if applied together with transfers between coun-
We thank Khalil Héliouli for discussions and comments on the subject of this paper.