Support for the astronomical theory of climatic change

AMONG recent papers supporting the astronomical theory of climatic change1–5, the work of Hays et al.5 is of particular importance in providing detailed quasi-periods from deep-sea cores. I wish to draw attention here to the fact that the periods found are very close to the periods predicted by Berger6,7 in the latest and most accurate calculation of the variations of the various ‘Milankovitch’ parameters. The roughly 24,000- and 19,500-yr periods from the core samples are not significantly different from the periods associated with the largest amplitude terms in the series expansion of the precessional parameter e sin ω the periods around 42,000 yr are essentially identical with the most important term in the expansion of the obliquity ε and the peaks in the range of 106,000 yr containing most of the variance, might be regarded as either a contribution from the eccentricity, where a weighted mean of the main amplitude terms has a period of 110,753 yr, or as a beat effect of precessional periods, as has been noted by Wigley8.