Sea-Level Fluctuations as Evidence of the Milankovitch Cycles and of the Planetary-Solar Modulation of Climate

Abstract

Eustatic fluctuations of sea level reflect Milankovitch cycles, but disclose also shorter periodicities, notably in the Holocene Epoch. Groups of beach ridges suggest possible solar-lunar cycles. A Hudson Bay storminess cycle of 45 yr varies also with longer-term periodicities that appear to match the 556-1112-1668 yr planetary and lunar cycles.

Terrestrial climate changes are believed to be triggered by three distinctive but interrelated exogenetic mechanisms, which are accelerated by endogenetic feedback processes. They are: (a) insolation modulated by terrestrial orbital motions, (b) solar radiation modulated by planetary torques and the Sun’s circumbarycentric motions, and (c) geomagnetic screening of solar emanations modulated by Earth-Moon, “twin planet” motions. Evidence is essentially phenomenological and systematic study is called for. The Milankovitch insolation effects appear to be either amplified or retarded by cumulative climatic effects of the short-term cycles.