Obliquity disruption and Antarctic ice sheet dynamics over a 2.4-Myr astronomical grand cycle

• DOI: 10.1126/sciadv.adl1996
• Publication Date: 2025-04-25T17:59:57Z
• Authors: Nicholas B. Sullivan; Stephen R. Meyers; Richard H. Levy; Robert M. McKay; Tina van de Flierdt; James Marschalek; Matteo Perotti; Luca Zurli; Franco Talarico; David Harwood; Laura De Santis; Fabio Florindo; Tim R. Naish; Georgia R. Grant; Molly O. Patterson
• Keywords: Antarctic ice sheet; Milankovitch cycles; Ice-sheet model

Marine δ 18 O data reveal astronomical forcing of the climate and cryosphere during Miocene, when atmospheric P co 2 was on par with emissions scenarios over next century. This inspired hypotheses for how Milankovitch cycles, ice-ocean interactions, greenhouse gases influence ice volume. Mass balance controls marine terrestrial sheets differ, proxy collected far from Antarctica provide valuable but limited insight into regional processes. We evaluate clast abundance Antarctic sedimentary records, observing a strong signal eccentricity precession coincident sheet clear obliquity at margins sheet. These analyses are integrated synthesis data, we argue that high variance in (mediated enhanced by ocean atmosphere) can inhibit growth, even insolation is conducive to glaciation. “obliquity disruption” explains variability before existence large northern hemisphere sheets.