Abstract. Spectral and wavelet analysis reveal the chain of close phase and coherence relationships at the obliquity frequency in variations of the tilt of the Earth's rotational axis (obliquity), frequency of large volcanic eruptions (E f ) along the Pacific Ring of Fire, and climate characteristics, represented by the relative content of oxygen-18 (δ 18 O) in the calcite of fossil benthic foraminifers (prominent LR04 stack), Antarctic and Greenland ice core data. The links revealed show that powerful 41,000-year rhythms in the Plio-Pleistocene climate variations can be caused by geophysical and geochemical effects of global volcanic activity which is induced by the forced obliquity oscillations.