[M-IS18] Paleoclimatology and paleoceanography

[MIS18-01] Emergent constraints on uncertainties of future precipitation change

★Invited Papers

*Hideo Shiogama¹, Masahiro Watanabe², Hyungjun Kim^3,4,5, Nagio Hirota¹ (1.National Institute for Environmental Studies, 2.Atmosphere and Ocean Research Institute, The University of Tokyo, 3.Moon Soul Graduate School of Future Strategy, Korea Advanced Institute of Science and Technology, 4.Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, 5.Institute of Industrial Science, the University of Tokyo)

Keywords:Climate change, Uncertainty constraints

Future projections of global mean precipitation change (ΔP) based on Earth system models (ESMs) have larger uncertainties than those of global mean temperature changes (ΔT). While many observational constraints on ΔT have been proposed, constraints on ΔP have not been well studied and are often complicated by the large influence of aerosols on precipitation. We are the first to succeed in observationally constraining the uncertainty in the global mean precipitation changes up to the end of the 21^st century by reducing the confounding influence of anthropogenic aerosols in our analysis. In addition to the constraints of ΔT, the upper end of the ΔP in the CMIP5/6 ESMs is lowered based on the consistency with the observed datasets: the 95^th percentile value of the ΔP up to the end of the 21^st century is lowered from 6.2% in the raw CMIP5/CMIP6 ESMs to 5.2-5.7% under the medium greenhouse gas concentration scenario. The variance of ΔP can be reduced by 8-30%. The observationally constrained ranges of ΔP should provide further reliable information for impact assessments.