Connecting the Atlantic Meridional Overturning Circulation to the Southern Ocean following the closure of equatorial seaways during the Cenozoic

Pineau, E., Lique, C., Ferreira, D. ORCID: https://orcid.org/0000-0003-3243-9774, Huck, T., Ladant, J.-B., Fabre, E., Millot-Weil, J. and Donnadieu, Y. (2026) Connecting the Atlantic Meridional Overturning Circulation to the Southern Ocean following the closure of equatorial seaways during the Cenozoic. Geophysical Research Letters, 53 (2). e2025GL119115. ISSN 1944-8007 doi: 10.1029/2025GL119115

Abstract/Summary

Global ocean circulation regulates climate and has undergone significant changes over the Cenozoic. Today, the Atlantic Meridional Overturning Circulation (AMOC) is driven by North Atlantic Deep Water (NADW) formation and Southern Ocean upwelling. By contrast, during the middle Eocene to early Oligocene (48–28 Ma), a restricted Drake Passage was limiting the northern Ekman transport, while a circum-equatorial current sustained by trade winds promoted low-latitude upwelling. Our set of simulations with the IPSL-CM5A2 model reveals that this paleogeographic setting favored proto-NADW upwelling at low latitudes, confining the AMOC to the Northern Hemisphere. Consequently, the role of southern westerly winds was limited, and the northward heat transport was weaker than in the modern ocean.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/127942
Identification Number/DOI	10.1029/2025GL119115
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Geophysical Union
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