Steinhilber et al, 2012: “A comparison of the derived solar activity with a record of Asian climate derived from δ18O in a Chinese stalagmite reveals a significant correlation. The correlation is remarkable because the Earth’s climate has not been driven by the Sun alone.” http://www.pnas.org/content/109/16/5967.full.pdf+html?with-ds=yes
Steinhilber et al – We reconstructed the solar activity (total solar irradiance) from the cosmic ray record. First, we reconstructed the solar modulation potential which is a measure of the solar modulation of the cosmic ray particles by removing the effect of the geomagnetic field based on paleomagnetic data (Knudsen 2008).
Korte – GeoPolar (Vukcevic) The Korte et al (2005) CALS7k.2 surface distribution data (5000 BC – 2000 AD) is used to construct ‘GeoPolar’ geomagnetic function, which is simply the surface radial magnetic field intensity between two geographic poles (BrN - BrS)
Visual comparison of two sets of periodograms would suggest that for the periods above 450 years, the climate periodicity shows higher correlation with the GeoPolar than the solar (TSI) magnetic field oscillations as derived from cosmogenic nuclide production.