A correlation between Earth’s inclinations and the times of the cold events recorded in Devils Hole climate data

The calculated values of Earth’s inclinations during the cold events in the 500 kyr climate record of Devils Hole show a correlation: they cluster in the regions around 1 and 2 degrees. The Devils Hole record has been chosen, since it was dated by absolute methods. Other climate records covering the same period also have a reduced number of cold events between the two regions. The correlation lends support to the proposal of R. A. Muller and G.J. MacDonald that the observed 100 kyr climate cycle is due to the varying inclination of Earth’s orbit and to material located near the invariant plane which shields off the solar radiation. The climate of the late Pleistocene (ca. 800 11.5 kyr BP) shows a 100 kyr glacial cycle. Muller and McDonald [1] proposed that this feature is caused by variations of the inclination, i.e. the tilt of Earth’s orbital plane, rather than by eccentricity variations, as assumed in the Milankovitch theory. Their model implies that some gas or dust was located near the invariant plane, which reduced the solar radiation on Earth whenever the inclination was smaller than the angle delimiting this cloud. The present paper reports a correlation between the values of Earth’s orbital inclination and the times of the cold events using the climate record of Devils Hole [3]. This record (Fig. 1) is chosen because the ages of the calcite specimens were determined by the U-Th method. The inclination of the Earth, also displayed in Fig. 1, was calculated by Quinn et al [4] and transformed into the invariable plane by Muller [2]. Fig. 2 shows that the inclinations at the times of the temperature minima mostly lie within two regions, which are centred at about 1 and 2 degrees, respectively. Fig. 2 indicates that the correlation does not depend on the age of