Tree rings reveal globally coherent signature of cosmogenic radiocarbon events in 774 and 993 CE

Open access
Date
2018Type
- Journal Article
Citations
Cited 80 times in
Web of Science
Cited 86 times in
Scopus
ETH Bibliography
yes
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Abstract
Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the 14C content in 484 individual tree rings formed in the periods 770–780 and 990–1000 CE. Distinct 14C excursions starting in the boreal summer of 774 and the boreal spring of 993 ensure the precise dating of 44 tree-ring records from five continents. We also identify a meridional decline of 11-year mean atmospheric radiocarbon concentrations across both hemispheres. Corroborated by historical eye-witness accounts of red auroras, our results suggest a global exposure to strong solar proton radiation. To improve understanding of the return frequency and intensity of past cosmic events, which is particularly important for assessing the potential threat of space weather on our society, further annually resolved 14C measurements are needed. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000289625Publication status
publishedExternal links
Journal / series
Nature CommunicationsVolume
Pages / Article No.
Publisher
Nature Publishing GroupOrganisational unit
08619 - Labor für Ionenstrahlphysik (LIP) / Laboratory of Ion Beam Physics (LIP)
Funding
157187 - Improving Late Glacial European tree-ring chronologies for accurate climate archive dating – Consolidation and extension of the Swiss-German pine chronology back to 14 000 BP (SNF)
Related publications and datasets
Is referenced by: https://doi.org/10.1038/s41467-018-07636-6
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Show all metadata
Citations
Cited 80 times in
Web of Science
Cited 86 times in
Scopus
ETH Bibliography
yes
Altmetrics