Green2Ice ERC Synergy
Published January 8, 2026 | Version v1
Journal article Open

Bipolar volcanic ice-core synchronization of the entire last glacial period

Authors/Creators

  • 1. ROR icon University of Copenhagen
  • 2. ROR icon University of Manitoba
  • 3. Københavns Universitet Niels Bohr Instituttet
  • 4. Kobenhavns Universitet Niels Bohr Institutet
  • 5. ROR icon Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
  • 6. ROR icon University of Göttingen
  • 7. ROR icon University of Bern
  • 8. CNRS Délégation Ile-de-France Sud
  • 9. ROR icon Laboratoire des Sciences du Climat et de l'Environnement
  • 10. CNRS en Alpes
  • 11. ROR icon British Antarctic Survey
  • 12. EDMO icon University of Cambridge Department of Earth Sciences
  • 13. ROR icon University of St Andrews
  • 14. University of Florence, Italy
  • 15. ROR icon Desert Research Institute
  • 16. Eawag, Dübendorf, Switzerland
  • 17. ROR icon Lund University

Description

Precise synchronization of paleoclimate records is essential for inferring the dynamics and past evolution of the climate system. For the last glacial period, the time scales of ice cores from the Greenland and Antarctic ice sheets have been synchronized by the use of cosmogenic radionuclides, atmospheric gas concentrations, and traces of large volcanic eruptions. Here we identify the sulfate deposition signatures of the same 300 volcanic eruptions in different Greenland and Antarctic ice cores to obtain an interhemispheric volcanic ice-core synchronization of the entire last glacial period and the early Holocene (10–110 ka). Compared to earlier bipolar volcanic synchronizations, we close a gap in the period 16.5–24.5 ka and extend the synchronization to cover the 10–12 ka and 60–110 ka intervals. Furthermore, we increase the density of bipolar match points and make updates and corrections of the existing bipolar and unipolar synchronizations. The volcanic synchronization is in agreement with existing bipolar synchronizations from independent 10Be and methane matching. The bipolar volcanic synchronization allows us to determine the precise phasing of interhemispheric abrupt climate events throughout the last glacial period, particularly those associated with Dansgaard-Oeschger (D-O) events. Our improved synchronization and extended time period allow us to show that at the time of the D-O warming transitions, the average Antarctic temperature reaches a maximum within decades after the Greenland temperature maximum. This rapid Antarctic warming is superimposed on the well-known millennial-scale thermal bipolar-seesaw warming in Antarctica commonly attributed to oceanic heat transport and confirms earlier work that the abrupt change observed in Greenland is associated with a direct atmospheric circulation change at a global scale. The exception to this pattern occurs for the EDML ice-coring site located in the Atlantic sector of Antarctica, potentially related to sea-ice conditions in the Weddell Sea. Comparison to state-of-the-art climate model simulations shows excellent agreement in the overall bipolar climate phasing at the warming transitions and allows for analysis of the climate-system behavior at those transitions. The model simulations suggest that the abrupt Antarctic warming response observed is connected with an interhemispheric atmospheric response involving a global scale reorganization of the zonal mean atmospheric circulation. The abrupt D-O surface warming signal in the Northern Hemisphere is teleconnected into an abrupt Antarctic surface warming through changes in the Southern Hemisphere eddy-driven jet and anomalous circulation changes in the associated Ferrel and Polar cells.

Files

1-s2.0-S027737912500575X-main.pdf

Files (19.5 MB)

Name Size Download all
md5:2c5a6343355f5a01fce6a1dfa199c9d3
19.5 MB Preview Download

Additional details

Funding

European Commission
Green2Ice - When was Greenland ‘green’? – Perspectives from basal ice and sediments from ice cores. 101072180
U.S. National Science Foundation
2315928
European Commission
TiPES - Tipping Points in the Earth System 820970
European Commission
P2F - PAST TO FUTURE: TOWARDS FULLY PALEO-INFORMED FUTURE CLIMATE PROJECTIONS 101184070
Swiss National Science Foundation
Danmarks Frie Forskningsfond
1131-00007B
U.S. National Science Foundation
2102917
U.S. National Science Foundation
1702830
European Research Council
820047