September 27, 2025Open Access

Collapse of the Atlantic Meridional Ocean Circulation Induced by Precession: Sensitivity to Orbital Acceleration

Key Points

A complete collapse of the AMOC can occur due to precessional forcing under specific orbital conditions.
The study shows that high eccentricity and low atmospheric CO2 result in a complete AMOC collapse without freshwater hosing.
Multi-millennial timescales for AMOC response indicate that orbital acceleration techniques may hide abrupt transition detection.
The findings highlight the importance of accurately modeling orbital forcings in AOGCM for climate studies.

Abstract

Abstract While orbital forcing‐induced weakening of the Atlantic meridional overturning circulation (AMOC) potentially facilitated glacial initiation during the Quaternary glacial‐interglacial cycles, this mechanism has remained to be confirmed by atmosphere‐ocean general circulation models (AOGCMs). Our simulations with an AOGCM demonstrate that without any freshwater hosing, a complete AMOC collapse can be achieved through precessional forcing alone under high eccentricity and relatively low atmospheric CO 2 level ( p CO 2 ). Crucially, the multi‐millennial timescale required for full AMOC response to precessional forcing suggests that the orbital acceleration techniques in AOGCM simulations, often adopted to save computation time, likely obscured detection of these abrupt AMOC transitions in previous studies.

Read Full Paperexternally

Mark Helpful

Bookmark

Relay

View Full Paper