Differentiating commitments world wide: global differentiation of GHG emissions reductions based on the Triptych approach - a preliminary assessment

In the context of global climate negotiations various approaches have been proposed to distribute commitments regarding greenhouse gas emissions mitigation over different countries. One of them is the Triptych approach, which is a sector approach that accounts for differences in national circumstances such as population size and growth, standard of living, economic structure and fuel mix in power generation. It was successfully applied in the negotiations on differentiation of commitments in the European Union in 1997. In this study we aim to see what problems we encounter when applying the approach in a wider geographical context. In order to reach this aim we establish a test differentiation of CO2 emission reduction obligations for a selection of 48 countries. The criteria we apply comprise technical emission reduction options only. According to our Triptych criteria, including the choice for particular growth scenarios and a convergence of CO2 emissions in the domestic sectors by the year 2030, the sum of CO. emissions in the 48 countries in 2015 is estimated to increase by 8% over 1990 levels. With the criteria used the average reduction objective for the OECD will be somewhere between - 10% and - 20%. For economics in transition to a market economy our calculations indicate on average a reduction between - 30% and - 50%. For the developing countries we established increases varying roughly from + 40% to + 200%. The choice for a particular growth scenario as well as the assumption for the period for the convergence of per capita emissions in the domestic sectors are crucial and may effect the outcome of the calculations to a large extent. If these problems can be sufficiently solved the Triptych approach can serve as a valuable toot to rank countries in a global differentiation scheme. (C) 2001 Elsevier Science Ltd. All rights reserved.