Contributions of Greenhouse Gases and Solar Activity to Global Surface Temperature Trends From Cmip6 Climate Models Simulations

Quantitative estimates of the contributions of anthropogenic impacts, characterized by changes in the radiative forcing of greenhouse gases in the atmosphere, and solar activity variations to the trends of global surface temperature on secular temporal horizons are obtained from simulations with climate models of the CMIP6 ensemble in comparison with corresponding estimates based on the analysis of long-term observational data since the 19th century using autoregressive models. The results for simulations with climate models characterized by low, medium and high temperature sensitivity to changes in СО content in the atmosphere are compared. It is found, in particular, that empirical estimates revealing the determinative contribution of the content of greenhouse gases in the atmosphere to the global surface temperature trends on half-century and century-long time intervals are most consistent with the estimates from simulations with the INM-CM4-8 climate model of G.I. Marchuk Institute of Numerical Mathematics RAS with the lowest sensitivity of global surface temperature to doubling the СО content in the atmosphere.