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

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.Kirdyanov;Paul J.Krusic;Carlos Le Quesne;Fredrik C.Ljungqvist;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

Department of Geography,University of Cambridge,Cambridge CB2 3EN,UK;Swiss Federal Research Institute(WSL),Birmensdorf 8903,Switzerland;Global Change Research Centre(CzechGlobe),Brno 60300,Czech Republic;Department of Geography,Faculty of Science,Masaryk University,Brno 61300,Czech Republic;Forest Biometrics Laboratory,Faculty of Forestry,"Stefan cel Mare"University ofSuceava,Suceava 720229,Romania;Department of Biology,Chemistry and Geography,University of Quebec in Rimouski,Rimouski Qc.G5L 3A1,Canada;Archaeology&Palaeoecology,School of Natural and Built Environment,Queen's University Belfast,Belfast BT7 1NN,UK;Department of Geology,State University of New York at Cortland,Cortland NY 13045,USA;CNR-IBE,Institute of BioEconomy,National Research Council,Trento 38121,Italy;School of Environment,The University of Auckland,Auckland 1010,New Zealand;Laboratorio de Dendrocronología y Cambio Global,Universidad Austral de Chile,Valdivia 509000,Chile;Centerfor Climate and Resilience Research(CR),Santiago 8370449,Chile;Cape Horn International Center(CHIC),Punta Arenas 6200000,Chile;Institute of Ecology and Geography,Siberian Federal University,Krasnoyarsk 660041,Russia;Tree-Ring Laboratory,Lamont-Doherty Earth Observatory,Columbia University,Palisades NY 10964,USA;Department of Environmental Science,William Paterson University,Wayne NJ 07470,USA;Department of Geography,Johannes Gutenberg University,Mainz 55099,Germany;Institute of Plant and Animal Ecology,Ural Branch,Russian Academy of Sciences,Yekaterinburg 620144,Russia;Ural Institute of Humanities,Ural Federal University,Yekaterinburg 620002,Russia;Laboratory of Tree-Ring Research,University of Arizona,Tucson AZ 85721,USA;Sukachev Institute of Forest SB RAS,Krasnoyarsk 660036,Russia;Department of Physical Geography,Bolin Centre for Climate Research,Stockholm University,Stockholm 10691,Sweden;Department of History,Stockholm University,Stockholm 10691,Sweden;Bolin Centre for Climate Research,Stockholm University,Stockholm 10691,Sweden;Swedish Collegium for Advanced Study,Uppsala 75238,Sweden;Initiative for the Science of the Human Past,Department of History-Max Planck Harvard Research Center for the Archaeoscience of the Ancient Mediterranean,Harvard University,Cambridge MA 02138,USA;Institute of Humanities,Siberian Federal University,Krasnoyarsk 660041,Russia;Department of Geography,University of Innsbruck,Innsbruck 6020,Austria;The University of New South Wales,Sydney NSW 2052,Australia;Key Laboratory of Desert and Desertification,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;Change Impacts and Risks in the Anthropocene(C-CIA),Institute for Environmental Sciences,University of Geneva,Geneva 1205,Switzerland;Department of Earth Sciences,University of Geneva,Geneva 1205,Switzerland;Department F.-A.Forel for Environmental and Aquatic Sciences,University of Geneva,Geneva 1205,Switzerland;National Scientific and Technical Research Council,Institute Argentina de Nivología,Glaciología y Ciencias Ambientales,Mendoza CP 5500,Argentina;Department of Earth Sciences,the College of Wooster,Wooster OH 44691,USA;Center for Excellence in Tibetan Plateau Earth Sciences,Chinese Academy of Sciences,Beijing 100101,China

科学通报（英文版）

[1]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.Kirdyanov;Paul J.Krusic;Carlos Le Quesne;Fredrik C.Ljungqvist;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-.Global wood anatomical perspective on the onset of the Late Antique Little Ice Age(LALIA)in the mid-6th century CE)[J].科学通报（英文版）,2022(22):2336-2344

Antique,LALIA,spells,incursion,dendrochronological

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