Sea ice fluctuations in the Baffin Bay and the Labrador Sea during glacial abrupt climate changes

Federico Scoto, Henrik Sadatzki, Niccolo Maffezzoli, Carlo Barbante, Alessandro Gagliardi, Cristiano Varin, Paul Vallelonga, Vasileios Gkinis, Dorthe Dahl-Jensen, Helle Astrid Kjaer, Francois Burgay, Alfonso Saiz-Lopez, Ruediger Stein, Andrea Spolaor

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Abstract

Sea ice decline in the North Atlantic and Nordic Seas has been proposed to contribute to the repeated abrupt atmospheric warmings recorded in Greenland ice cores during the last glacial period, known as Dansgaard-Oeschger (D-O) events. However, the understanding of how sea ice changes were coupled with abrupt climate changes during D-O events has remained incomplete due to a lack of suitable high-resolution sea ice proxy records from northwestern North Atlantic regions. Here, we present a subdecadal-scale bromine enrichment (Brenr) record from the NEEM ice core (Northwest Greenland) and sediment core biomarker records to reconstruct the variability of seasonal sea ice in the Baffin Bay and Labrador Sea over a suite of D-O events between 34 and 42 ka. Our results reveal repeated shifts between stable, multiyear sea ice (MYSI) conditions during cold stadials and unstable, seasonal sea ice conditions during warmer interstadials. The shift from stadial to interstadial sea ice conditions occurred rapidly and synchronously with the atmospheric warming over Greenland, while the amplitude of high-frequency sea ice fluctuations increased through interstadials. Our findings suggest that the rapid replacement of widespread MYSI with seasonal sea ice amplified the abrupt climate warming over the course of D-O events and highlight the role of feedbacks associated with late-interstadial seasonal sea ice expansion in driving the North Atlantic ocean-climate system back to stadial conditions.

Original languageEnglish
Article number2203468119
JournalProceedings of the National Academy of Sciences of the United States of America
Volume119
Issue number44
Number of pages9
ISSN0027-8424
DOIs
Publication statusPublished - 1 Nov 2022

Keywords

  • sea ice reconstruction
  • Baffin Bay
  • Labrador Sea
  • abrupt climate changes
  • Dansgaard-Oeschger events
  • NORTH-ATLANTIC
  • GREENLAND
  • RECORD
  • RECONSTRUCTION
  • TEMPERATURE
  • CIRCULATION
  • MARINE
  • INFORMATION
  • INSTABILITY
  • SEASONALITY

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