Exploring the 2 °C Target Scenarios by Considering Climate Benefits and Health Benefits – Role of Biomass and CCS

Abstract

This study analyzes emissions pathways of the greenhouse gases (GHGs) and evaluates cobenefits and tradeoffs among GHGs, air-pollutions and short-lived climate pollutants (SLCPs) emissions, while taking mitigation actions for achieving a 2▪ global temperature change limit above pre-industrial levels, so called the 2▪ target. This study focuses on the following points; 1) technological mitigation potentials and costs of GHGs, 2) cobenefits in reducing of SLCPs and air pollutants due to the effects of low-carbon measures, 3) tradeoffs of increasing SLCPs and air pollutants due to implementing coal and biomass power plants with CCS, 4) effects of air pollutant control measures in addition to low-carbon measures. Carbon price for achieving the 2▪ target is expensive, reaching at around 400 US$/tCO2 in 2050. However, large cobenefits in reducing SLCPs and air pollutants are identified due to energy efficiency improvements on the demand sectors and energy shifting from fossil fuels to non-fossil fuel energies on the supply sector. On the other hand, emissions rebounds such as SO2, BC, PM2.5 are found when implementing more coal and biomass power plants with CCS. Even if emissions rebound are arose, it is technologically possible by promoting additional air pollutant control measures to reduce SO2, BC, PM2.5, around 80-90% reductions compared to the 2010 level. To explore the 2▪ target pathways from the viewpoint of balancing climate impacts and health impacts, it is necessary to discuss reduction profiles of air pollutants and SLCPs carefully by the combination of measures on CO2 and air pollutants.