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

TL;DR

This study quantifies the relative impacts of greenhouse gases, especially CO2, and solar activity on long-term global temperature trends using CMIP6 climate model simulations and observational data, highlighting CO2's dominant role.

Contribution

It provides a comparative analysis of climate model simulations and observational data to estimate the contributions of greenhouse gases and solar activity to climate change.

Findings

CO2 has a determinative contribution to long-term temperature trends.

Models with low temperature sensitivity to CO2 align best with observational data.

Solar activity's impact is comparatively less significant over the studied periods.

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.