Glacial cycles during the Early Pleistocene epoch are characterized by a dominant 41,000-year periodicity and amplitudes smaller than those of glacial cycles with 100,000-year periodicity during the Late Pleistocene. However, it is unclear how the 41,000-year glacial cycles during the Early Pleistocene respond to Earth’s astronomical forcings. An artist’s impression of how astronomical forces affect the Earth’s motion, climate, and ice sheets....
