Recently, simulations of newly developed climate models that participate at the Coupled Model Intercomparison Project in its sixth phase (CMIP6) became available. These models show a higher mean effective climate sensitivity (ECS) than CMIP5 models (4.0 °C vs 3.2 °C) and several CMIP6 simulate an ECS outside of the IPCC AR5 likely range of 1.5 – 4.5 °C. What feedback processes are responsible and how does the increased ECS influence the simulated historical warming? Can the warming simulated by the CMIP5 and CMIP6 ensembles be reconciled with observed warming after accounting for internal variability in the tropical Pacific? We compare different methods of estimating the Pacific contribution to the difference between modelled and observed warming on a decadal time scale and explain why previous studies came to differing conclusions.
08.10.2019
15:15 Uhr