Empirical analysis of the solar contribution to global mean air surface temperature change

TL;DR

This paper empirically analyzes the solar contribution to global temperature change using a bi-scale climate model, highlighting uncertainties due to different solar irradiance data sets and reconstructing temperature patterns over 400 years.

Contribution

It introduces an empirical bi-scale climate model with fast and slow responses to solar forcing, calibrated on recent temperature data, and reconstructs long-term solar-induced temperature variations.

Findings

Solar contribution varies from slight cooling to significant warming depending on data set.

Model captures 400-year temperature patterns linked to solar activity.

Uncertainty in solar irradiance data affects attribution of recent warming.

Abstract

The solar contribution to global mean air surface temperature change is analyzed by using an empirical bi-scale climate model characterized by both fast and slow characteristic time responses to solar forcing: $\tau_1 =0.4 \pm 0.1$ yr, and $\tau_2= 8 \pm 2$ yr or $\tau_2=12 \pm 3$ yr. Since 1980 the solar contribution to climate change is uncertain because of the severe uncertainty of the total solar irradiance satellite composites. The sun may have caused from a slight cooling, if PMOD TSI composite is used, to a significant warming (up to 65% of the total observed warming) if ACRIM, or other TSI composites are used. The model is calibrated only on the empirical 11-year solar cycle signature on the instrumental global surface temperature since 1980. The model reconstructs the major temperature patterns covering 400 years of solar induced temperature changes, as shown in recent paleoclimate global temperature records.