Observational constraints on economic impact assessments of climate change simulated by an impact emulator

Abstract

Since many new generation earth system models (ESMs) have been suggested to be ‘hot models’ that overestimate future global warming, the IPCC AR6 used the constrained range of global warming instead of that in the raw ensemble. However, it is not clear how this advance in climate science can contribute to reducing climate-related uncertainties in impact assessments. Here, we show that the climate-related uncertainty of the economic impact of climate change in the world can be observationally constrained. By applying an impact emulator of Takakura et al. (2021, https://doi.org/10.5194/gmd-14-3121-2021), we estimate the economic impacts in nine sectors based on 67 ESMs’ future climate change projections. The impacts in eight sectors are closely related to the recent past trend of global mean temperature. Observational constraints lower the upper bound of the aggregate economic impact simulated by the single emulator from 2.9% to 2.5% of the world gross domestic product and reduce 31% of variance under the RCP4.5 or SSP2-4.5 scenarios. Please see Shiogama et al. (2022, https://doi.org/10.1088/1748-9326/aca68d) for more details.