Abstract

In the coming years the international debate on commitments for the second commitment period under the Kyoto Protocol will intensify. In this study, the Global Triptych approach is put forward as an input for international decision-making concerning the differentiation of commitments by 2020. It is a sector- and technology-oriented approach, and we calculated quantitative emission limitation objectives and global emissions starting from bottomup information on long-term reduction opportunities. Central to the calculations were long-term sustainability targets for the year 2050, formulated for (1) energy efficiency in the energy-intensive industry, (2) greenhouse gas intensity of electricity production, and (3) per capita emissions in the domestic sectors. Calculated emission limitation objectives for 13 world regions ranged from about −30% to more than +200%. The ranking of world regions in the differentiation turned out to be independent of the levels chosen for the long-term sustainability targets. The objectives seem sufficient to maintain the long-term possibility of stabilizing atmospheric greenhouse gas concentrations at about 550 ppm CO₂-eq, but will require severe emission reductions. These may be relaxed to a certain degree if stabilization at 650 ppm CO₂-eq is aimed for. We conclude that the bottom-up character of the approach made it possible to examine important basic principles of the Climate Convention, including equity, the needs and circumstances of developing countries, cost-effectiveness and sustainable development.