Forcing of paleoclimate

A large number of investigations of paleoclimate have noted the influence of a ∼ 200 year oscillation which has been related to the De Vries/Suess cycle of solar activity. As such studies were concerned mostly with local climate, we have used extensive northern hemispheric proxy data sets of Büntgen and of 5 Christiansen/Ljungqvist together with a southern hemispheric tree-ring set, all with 1 year time resolution, to analyze the climate influence of the solar cycle. As there is increasing interest in temperature rise rates, as opposed to present absolute temperatures, we have analyzed temperature differences over 100 years to shed light on climate dynamics of at least the last 2500 years. Fourier-and Wavelet transforms as 10 well as nonlinear optimization to sine functions show the dominance of the ∼ 200 year cycle. The sine wave character of the climate oscillations permits an approximate prediction of the near future climate.