Contributions of greenhouse gases and solar activity to global climate change from CMIP6 models simulations

Abstract: Quantitative estimates of the contributions of the anthropogenic forcing, characterized by changes in the radiative forcing of atmospheric greenhouse gases (CO2, in particular), and solar activity variations to the trends of the global surface temperature on secular temporal horizons are obtained with the aid of autoregressive models from simulations with climate models of the CMIP6 ensemble and from long-term observational data since the 19th century. The results for the simulations with climate models characterized by low, medium and high temperature sensitivity to changes in the CO2 content are compared. It is found, in particular, that the estimates from observation data revealing the determinative contribution of the CO2 content to the global surface temperature trends on half-century and century-long time intervals are most consistent with the estimates from simulations with the climate model with the lowest sensitivity of the global surface temperature to doubling the CO2 atmospheric content.