Mid-Holocene Antarctic sea-ice increase driven by marine ice sheet retreat

Research output: Contribution to journalArticlepeer-review

Authors

  • Kate Ashley
  • Robert McKay
  • Johan Etourneau
  • Francis Jimenez-Espejo
  • Alan Condron
  • Anna Albot
  • Xavier Crosta
  • Christina Riesselman
  • Osamu Seki
  • Guillaume Massé
  • Nicholas Golledge
  • Edward Gasson
  • Daniel Lowry
  • Katelyn Johnson
  • Nancy Bertler
  • Carlota Escutia
  • Robert Dunbar

Colleges, School and Institutes

Abstract

Over recent decades Antarctic sea-ice extent has increased, alongside widespread ice shelf thinning and freshening of waters along the Antarctic margin. In contrast, Earth system models generally simulate a decrease in sea ice. Circulation of water masses beneath large-cavity ice shelves is not included in current Earth System models and may be a driver of this phenomena. We examine a Holocene sediment core off East Antarctica that records the Neoglacial transition, the last major baseline shift of Antarctic sea ice, and part of a late-Holocene global cooling trend. We provide a multi-proxy record of Holocene glacial meltwater input, sediment transport, and sea-ice variability. Our record, supported by high-resolution ocean modelling, shows that a rapid Antarctic sea-ice increase during the mid-Holocene (∼ 4.5 ka) occurred against a backdrop of increasing glacial meltwater input and gradual climate warming. We suggest that mid-Holocene ice shelf cavity expansion led to cooling of surface waters and sea-ice growth that slowed basal ice shelf melting. Incorporating this feedback mechanism into global climate models will be important for future projections of Antarctic changes.

Details

Original languageEnglish
Pages (from-to)1-19
JournalClimate Of The Past
Volume17
Issue number1
Publication statusPublished - 5 Jan 2021