Rapid reductions and millennial-scale variability in Nordic Seas sea ice cover during abrupt glacial climate changes

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Constraining the past sea ice variability in the Nordic Seas is critical for a comprehensive understanding of the abrupt DansgaardOeschger (D-O) climate changes during the last glacial. Here we present unprecedentedly detailed sea ice proxy evidence from two Norwegian Sea sediment cores and an East Greenland ice core to resolve and constrain sea ice variations during four D-O events between 32 and 41 ka. Our independent sea ice records consistently reveal a millennial-scale variability and threshold response between an extensive seasonal sea ice cover in the Nordic Seas during cold stadials and reduced seasonal sea ice conditions during warmer interstadials. They document substantial and rapid sea ice reductions that may have happened within 250 y or less, concomitant with reinvigoration of deep convection in the Nordic Seas and the abrupt warming transitions in Greenland. Our empirical evidence thus underpins the cardinal role of rapid sea ice decline and related feedbacks to trigger abrupt and large-amplitude climate change of the glacial D-O events.

Original languageEnglish
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue number47
Pages (from-to)29478-29486
Number of pages9
ISSN0027-8424
DOIs
Publication statusPublished - 24 Nov 2020

    Research areas

  • sea ice, Nordic Seas, Dansgaard-Oeschger events, abrupt climate change, HIGH-RESOLUTION RECORD, NORTH-ATLANTIC, HALOGEN DEPOSITION, OCEAN CIRCULATION, BIOMARKER, MARINE, RECONSTRUCTIONS, INSTABILITY, CONVECTION, ANOMALIES

ID: 253650208