Global wood anatomical perspective on the onset of the Late Antique Little Ice Age (LALIA) in the mid-6th century CE

• DOI: 10.1016/j.scib.2022.10.019
• Publication Date: 2022-10-25T17:30:13Z
• Authors: Ulf Büntgen; Alan Crivellaro; Dominique Arseneault; Mike Baillie; David Barclay; Mauro Bernabei; Jarno Bontadi; Gretel Boswijk; David Brown; Duncan A. Christie; Olga V. Churakova; Edward R. Cook; Rosanne D’Arrigo; Nicole Davi; Jan Esper; Patrick Fonti; Ciara Greaves; Rashit M. Hantemirov; Malcolm K. Hughes; Alexander V. Kird...; Paul J. Krusic; Carlos Le Quesne; Fredrik C. Ljungq...; Michael McCormick; Vladimir S. Myglan; Kurt Nicolussi; Clive Oppenheimer; Jonathan Palmer; Chun Qin; Frederick Reinig; Matthew Salzer; Markus Stoffel; Max Torbenson; Mirek Trnka; Ricardo Villalba; Nick Wiesenberg; Greg Wiles; Bao Yang; Alma Piermattei
• Keywords: Little ice age; Paleoclimatology; Global cooling; Frost (temperature)

Linked to major volcanic eruptions around 536 and 540 CE, the onset of Late Antique Little Ice Age has been described as coldest period past two millennia. The exact timing spatial extent this exceptional cold phase are, however, still under debate because limited resolution geographical distribution available proxy archives. Here, we use 106 wood anatomical thin sections from 23 forest sites 20 tree species in both hemispheres search for cell-level fingerprints ephemeral summer cooling between 530 550 CE. After cross-dating double-staining, identified 89 Blue Rings (lack cell wall lignification), nine Frost (cell deformation collapse), 93 Light (reduced thickening) Northern Hemisphere. Our network reveals evidence strongest temperature depression mid-July early-August CE across North America Eurasia, whereas more localised spells occurred summers 532, 540-43, 548 lack signatures austral trees suggests incursion stratospheric aerosol into Southern Hemisphere extra-tropics, that any forcing was mitigated by atmosphere-ocean dynamical responses and/or concentrated outside growing season, or a combination factors. findings demonstrate advantage investigations over traditional dendrochronological measurements, provide benchmark Earth system models, support cross-disciplinary studies entanglements climate history, question relevance global averages.