Evaluating Multiple Emission Pathways for a Fixed Cumulative CO2 Emission from Socioeconomic Perspectives

Cumulative CO2 emission is a good indicator for climate stabilization. It has recently been used in socioeconomic research dealing with climate mitigation. However, previous studies do not focus on the socioeconomic impacts of choosing different emission pathways under fixed cumulative CO2 emissions. Such effects are important, since our capacity to reduce emissions may vary each year — thus affecting our policy choices. We develop five emission pathways based on a fixed cumulative CO2 emission (i.e., 812 GtC for this century). All pathways start declining emissions from the reference level in 2040 to attain zero by 2100. We determine the socioeconomic impacts for these pathways using a computable general equilibrium model. Our research indicates that the smaller the emissions, the higher the carbon prices each year. Differences in the global gross domestic product (GDP) among the pathways were less than 4% by 2090, while the differences in the cumulative GDP in terms of net present values were less than 0.1% (with a discount rate of 5%). Thus, there was limited dependence of GDP on pathway. The differences in the global primary energy demand among the pathways were more noticeable, although the largest difference in the cumulative demand was 4%.