The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) has set legally binding emissions targets for a basket of six greenhouse gases and timetables for industrialised countries. It has also incorporated three international flexibility mechanisms. However, the Articles defining the flexibility mechanisms carry wording that their Use Must be supplemental to domestic actions. This has led to the open debates on interpretations of these supplementarity provisions. Such debates ended at the resumed sixth Conference of the Parties (COP) to the UNFCCC, held in Bonn, July 2001, and Lit the subsequent COP-7 in Marrakesh. November 2001. The final wording in the Bonn Agreement, reaffirmed ill the Marrakesh Accords. at least indicates that domestic policies will have an important role to play ill meeting Annex B countries' emissions commitments. Carbon taxes have long been advocated because of their cost effectiveness in achieving a given emissions reduction. In this paper, the main economic impacts of carbon taxes are assessed. Based oil a review of empirical Studies on existing carbon, energy taxes, it is Concluded that competitive losses and distributive impacts are generally not significant and definitely less than Often perceived. However, given the ultimate objective of the Framework Convention, future carbon taxes could have higher rates than those already imposed and thus the resulting economic impacts Could be more acute. In this context, it has been shown that how to use the generated fiscal revenues will be of fundamental importance ill determining the final economic impacts of carbon taxes. Finally, we briefly discuss carbon taxes in combination with other domestic and international instruments. (C) 2003 Elsevier Ltd. All rights reserved.