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 .