Five million years of Antarctic Circumpolar Current strength variability - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Nature Année : 2024

Five million years of Antarctic Circumpolar Current strength variability

Frank Lamy
Gisela Winckler
Helge W Arz
Jesse R Farmer
Julia Gottschalk
Lester Lembke-Jene
Jennifer L Middleton
Michèlle van der Does
Ralf Tiedemann
Carlos Alvarez Zarikian
Chandranath Basak
  • Fonction : Auteur
Anieke Brombacher
  • Fonction : Auteur
Levin Dumm
  • Fonction : Auteur
Oliver M Esper
  • Fonction : Auteur
Lisa C Herbert
  • Fonction : Auteur
Shinya Iwasaki
Gaston Kreps
Vera J Lawson
Li Lo
  • Fonction : Auteur
Elisa Malinverno
  • Fonction : Auteur
Alfredo Martinez-Garcia
Simone Moretti
Christopher M Moy
Ana Christina Ravelo
Christina R Riesselman
Mariem Saavedra-Pellitero
Henrik Sadatzki
Inah Seo
  • Fonction : Auteur
Raj K Singh
Rebecca A Smith
  • Fonction : Auteur
Alexandre L Souza
Joseph S Stoner
  • Fonction : Auteur
Maria Toyos
Igor M Venancio P de Oliveira
Sui Wan
  • Fonction : Auteur
Shuzhuang Wu
Xiangyu Zhao
  • Fonction : Auteur

Résumé

Abstract The Antarctic Circumpolar Current (ACC) represents the world’s largest ocean-current system and affects global ocean circulation, climate and Antarctic ice-sheet stability 1–3 . Today, ACC dynamics are controlled by atmospheric forcing, oceanic density gradients and eddy activity 4 . Whereas palaeoceanographic reconstructions exhibit regional heterogeneity in ACC position and strength over Pleistocene glacial–interglacial cycles 5–8 , the long-term evolution of the ACC is poorly known. Here we document changes in ACC strength from sediment cores in the Pacific Southern Ocean. We find no linear long-term trend in ACC flow since 5.3 million years ago (Ma), in contrast to global cooling 9 and increasing global ice volume 10 . Instead, we observe a reversal on a million-year timescale, from increasing ACC strength during Pliocene global cooling to a subsequent decrease with further Early Pleistocene cooling. This shift in the ACC regime coincided with a Southern Ocean reconfiguration that altered the sensitivity of the ACC to atmospheric and oceanic forcings 11–13 . We find ACC strength changes to be closely linked to 400,000-year eccentricity cycles, probably originating from modulation of precessional changes in the South Pacific jet stream linked to tropical Pacific temperature variability 14 . A persistent link between weaker ACC flow, equatorward-shifted opal deposition and reduced atmospheric CO 2 during glacial periods first emerged during the Mid-Pleistocene Transition (MPT). The strongest ACC flow occurred during warmer-than-present intervals of the Plio-Pleistocene, providing evidence of potentially increasing ACC flow with future climate warming.
Fichier principal
Vignette du fichier
s41586-024-07143-3.pdf (55.45 Mo) Télécharger le fichier
Origine Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

hal-04574721 , version 1 (14-05-2024)

Identifiants

Citer

Frank Lamy, Gisela Winckler, Helge W Arz, Jesse R Farmer, Julia Gottschalk, et al.. Five million years of Antarctic Circumpolar Current strength variability. Nature, 2024, 627 (8005), pp.789 - 796. ⟨10.1038/s41586-024-07143-3⟩. ⟨hal-04574721⟩
20 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Mastodon Facebook X LinkedIn More