Regional emission pathways, energy transition paths and cost analysis under various effort-sharing approaches for meeting Paris Agreement goals

Abstract

International climate policy debate has been struggling to define an agreeable principle for just distribution of the burdens of reducing greenhouse gases. By the integrated assessment modeling, we investigate climate change mitigation pathways compatible with the Paris Agreement goals under different carbon budget allocation principles, namely, cost-effectiveness, equality, and grandfathering for 11 world regions. The results indicate that regional carbon quotas remain similar under equality and grandfathering principles, except for regions with a high population projection, i.e., Sub-Saharan Africa and South Asia, or regions with a high level of current emissions, such as North America. Irrespective of the burden-sharing principles, most world regions must reach carbon neutrality before 2070 to meet the 2 °C climate targets. Moreover, carbon emissions reduced by carbon capture and storage applications are found to peak around 2050. In general, the share of fossil fuels in primary energy is larger under the larger carbon quota, which will also increase carbon capture and storage applications in fossil fuels. The average global investment needs for mitigating climate change are the lowest under the cost-effectiveness principle, and the marginal abatement cost is the same for all regions. For each region, as the carbon quota decreases the marginal abatement cost increases, while the energy investment changes independently from the carbon quota. These insights can inform global climate change negotiations and help policymakers formulate timelines for carbon neutrality, energy transition, and technology deployment and investment portfolios.