Antarctic evidence for an abrupt northward shift of the Southern Hemisphere westerlies at 32 ka BP

• Published in: Nature Communications
• Main Authors: Abhijith U. Venugopal, Nancy A. N. Bertler, Jeffrey P. Severinghaus, Edward J. Brook, Giuseppe Cortese, James E. Lee, Thomas Blunier, Paul A. Mayewski, Helle A. Kjær, Lionel Carter, Michael E. Weber, Richard H. Levy, Rebecca L. Pyne, Marcus J. Vandergoes
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Portfolio 2023
• Subjects: Science; Q; Antarctic; Roosevelt Island; Southern Ocean; Antarc*; Antarctica; ice core
• Online Access: https://doi.org/10.1038/s41467-023-40951-1; https://doaj.org/article/e515b10b2933403ba12334357c7140d6

Abstract High-resolution ice core records from coastal Antarctica are particularly useful to inform our understanding of environmental changes and their drivers. Here, we present a decadally resolved record of sea-salt sodium (a proxy for open-ocean area) and non-sea salt calcium (a proxy for continental dust) from the well-dated Roosevelt Island Climate Evolution (RICE) core, focusing on the time period between 40–26 ka BP. The RICE dust record exhibits an abrupt shift towards a higher mean dust concentration at 32 ka BP. Investigating existing ice-core records, we find this shift is a prominent feature across Antarctica. We propose that this shift is linked to an equatorward displacement of Southern Hemisphere westerly winds. Subsequent to the wind shift, data suggest a weakening of Southern Ocean upwelling and a decline of atmospheric CO2 to lower glacial values, hence making this shift an important glacial climate event with potentially important insights for future projections.