[A-CG34] Projection and detection of global environmental change

[ACG34-08] Developing an Integrated Assessment Model to determine optimal cost-benefit paths for SSP1-5

*Xuanming Su¹, KIYOSHI TAKAHASHI¹, Tokuta Yokohata¹, Katsumasa Tanaka^2,1, Shinichiro Fujimori³, Jun’ya Takakura¹, Rintaro Yamaguchi¹, Weiwei Xiong² (1.National Institute for Environmental Studies, Japan, 2.Laboratoire des Sciences du Climat et de l’Environnement (LSCE), IPSL, CEA/CNRS/UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France, 3.Kyoto University, Japan)

Keywords:Integrated Assessment Model, SSP scenarios, cost-benefit, DICE model, optimal scenario

Recent Optimal-type Integrated Assessment Models are typically restricted to employing a single reference scenario and primarily focus on reducing CO₂ emissions. This may not adequately account for the uncertainties arising from diverse socioeconomic developments and the potential for mitigating the effects of individual greenhouse gas emissions, aerosols, and pollutants. We create an Integrated Assessment Model framework in this study by fusing a socioeconomic module with a reduced-complexity climate module. We represented the SSP scenarios by 1) calculating a new set of MAC curves based on the most recent AIM/Hub V2.2, 2) creating a new damage function based on an emulator that is less expensive, and 3) extending the evaluation time to the year 2500. The cost-benefit analysis reveals that all SSPs will have temperatures over the 2 ℃ climate target by the end of this century. All SSPs, with the exception of SSP3, will eventually reach a temperature below 1 ℃. SSP5 in particular will stabilize at almost zero temperature by the end of the evaluation period because of the high GDP growth rates and comparatively modest mitigation expenditures. Based on the cost-benefit analysis, our results show that rapid GDP development will eventually help mitigate the effects of climate change.