Response of atmospheric ground level temperatures to changes in the total solar irradiance

TL;DR

This study investigates how variations in total solar irradiance influence atmospheric ground temperatures across different time scales, finding minimal impact since 1975 and emphasizing the dominant role of CO2 in recent warming.

Contribution

It provides a comprehensive analysis of the relationship between TSI and ground temperature over multiple time scales, highlighting the limited influence of TSI on recent global warming.

Findings

Global temperature sensitivity to TSI varies from 0.003 K/(W/m^2) daily to 0.2 over decades.

Since 1975, TSI changes have negligible impact on global temperature increases.

Long-term TSI variations are more effective in influencing Earth's temperature than short-term changes.

Abstract

The attribution of part of global warming to changes in the total solar irradiance (TSI) is an important topic which is not, yet, fully understood. Here, we examine the TSI induced temperature (T) changes on a variety of time scales, from one day to centuries and beyond, using a variety of assumptions. Also considered is the latitude variation of the T-TSI correlations, where it appears that over most of the globe there is a small increase in the sensitivity of temperature to TSI in time. It is found that the mean global sensitivity (alpha)measured in K(Wm-2)-1 varies from about 0.003 for 1 day, via 0.05 for 11-years to about 0.2 for decades to centuries. We conclude that mean global temperature changes related to TSI are not significant from 1975 onwards. Before 1975, when anthropogenic gases were less important, many of the temperature changes can be attributed to TSI variations. Over much longer periods of time, from Kyear to Myear, the TSI changes are more efficient still, the sensitivity alpha increasing ro about 0.5. Since 1975 the changes in mean global temperature are not due to TSI changes, but rather to the increasing atmospheric CO2 content.