Synchronous volcanic eruptions and abrupt climate change ∼17.7 ka plausibly linked by stratospheric ozone depletion

• Published in: Proceedings of the National Academy of Sciences
• Main Authors: McConnell, Joseph R., Adkins, Jess F., Paris, Guillaume
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: National Academy of Sciences 2017
• Subjects: climate; deglaciation; volcanism; ozone; aerosol; Antarctic; Antarctic Peninsula; Byrd; Mount Takahe; Palisades; Takahe; The Antarctic; West Antarctic Ice Sheet; Antarc*; ice core; Ice Sheet
• Online Access: https://www.ncbi.nlm.nih.gov/pmc/PMC5617275; https://doi.org/10.1073/pnas.1705595114

Glacial-state greenhouse gas concentrations and Southern Hemisphere climate conditions persisted until ∼17.7 ka, when a nearly synchronous acceleration in deglaciation was recorded in paleoclimate proxies in large parts of the Southern Hemisphere, with many changes ascribed to a sudden poleward shift in the Southern Hemisphere westerlies and subsequent climate impacts. We used high-resolution chemical measurements in the West Antarctic Ice Sheet Divide, Byrd, and other ice cores to document a unique, ∼192-y series of halogen-rich volcanic eruptions exactly at the start of accelerated deglaciation, with tephra identifying the nearby Mount Takahe volcano as the source. Extensive fallout from these massive eruptions has been found >2,800 km from Mount Takahe. Sulfur isotope anomalies and marked decreases in ice core bromine consistent with increased surface UV radiation indicate that the eruptions led to stratospheric ozone depletion. Rather than a highly improbable coincidence, circulation and climate changes extending from the Antarctic Peninsula to the subtropics—similar to those associated with modern stratospheric ozone depletion over Antarctica—plausibly link the Mount Takahe eruptions to the onset of accelerated Southern Hemisphere deglaciation ∼17.7 ka. © 2017 the Author(s). Published by PNAS. This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND). https://creativecommons.org/licenses/by-nc-nd/4.0/ Edited by Wallace S. Broecker, Columbia University, Palisades, NY, and approved August 7, 2017 (received for review April 5, 2017). Published ahead of print September 5, 2017. We acknowledge R. von Glasow for help with snowpack model simulations, and J. Stutz and R. Kreidberg for helpful discussions. The US National Science Foundation supported this work [Grants 0538427, 0839093, and 1142166 (to J.R.M.); 1043518 (to E.J.B.); 0538657 and 1043421 (to J.P. Severinghaus); 0538553 and 0839066 (to J.C.-D.); and 0944348, 0944191, ...