Why has Earth experienced ice age cycles over the past several million years? How do changes to ocean nutrients cause CO2 concentration in the atmosphere to naturally change over the course of an ice age cycle?

Tides are caused by a differences in the gravitational force of the sun at different points on earth. differences in the gravitational force of the moon at different points on earth differences in earth’s gravitational field strength at different points on earth’s surfac fluctuations in the gravitational attraction between earth and the moon.