Our approach honors the Maunder Minimum and the Modern Maximum, the two bookends, and also honors the large temperature increase of 0.75℃ between 1700 and 1950. This temperature increase is attributed to solar forcing, since greenhouse gas (GHG) concentrations are very small or non-existent in this interval.
If the total solar irradiance, TSI, data of one model used by IPCC AR6 is scaled to match both temperature bookends, the hills and valleys in between show significant correlation with Earth’s temperature data. While not perfect, the tracking reinforces that solar influence is dominant in this period. This means that solar can still have a significant effect in years beyond 1950 if an upscaled effective TSI is included in the climate model. For example, if sunspot numbers stay constant until 2050, an increase in Earth temperature will reflect GHG forcing. But if sunspot numbers and effective TSI fall, GHG effects will be larger than that measured by Earth temper- ature rise. However, if sunspot numbers and effective TSI rise, GHG effects will be smaller than measured by Earth temperature rise.
Galactic cosmic rays (GCR) are modulated by the sun’s variability, and radionuclides in ice cores have extrapolated solar modulation back 10,000 years. The data indicate that the sun has modulated several glacier retreats on Earth over the past 2,000 years, and confirmed solar forc- ing of Earth’s climate. The search continues for a mechanism that magnifies the TSI effect. An unprecedented heating of Jupiter’s atmosphere by solar wind events may offer clues to under- stand heating of the Earth by solar control.