Das Projekt "Szenarien fuer die CO2-Reduktion und die Entwicklung der globalen Energienachfrage" wird vom Umweltbundesamt gefördert und von Paul Scherrer Institut durchgeführt. Based on a link between top-down and bottom-up models the study generates global CO2 scenarios and access options to mitigate greenhouse gases. Optimization analyses define the cost of CO2 mitigation, burden sharing and the efficiency of market orented mechanisms like global taxes, trading of emission permits, activities implemented jointly and the clean development mechanism. The model is based on MERGE-3 and has a resolution of 9 world regions. Leading Questions: Analyses of market mechanism, like taxes, trade of permits and AIJ. Burden sharing between industrialized and D Countries. Contribution of new technologies in reducing the mitigation cost. Timing in introducing control measures. Endogenous technological learning and CO2 mitigation cost.