| 1. |
- Büntgen, Ulf, et al.
(author)
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Cooling and societal change during the Late Antique Little Ice Age from 536 to around 660 AD
- 2016
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In: Nature Geoscience. - 1752-0894 .- 1752-0908. ; 9:3, s. 231-236
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Journal article (peer-reviewed)abstract
- Climatic changes during the first half of the Common Era have been suggested to play a role in societal reorganizations in Europe and Asia. In particular, the sixth century coincides with rising and falling civilizations, pandemics, human migration and political turmoil. Our understanding of the magnitude and spatial extent as well as the possible causes and concurrences of climate change during this period is, however, still limited. Here we use tree-ring chronologies from the Russian Altai and European Alps to reconstruct summer temperatures over the past two millennia. We find an unprecedented, long-lasting and spatially synchronized cooling following a cluster of large volcanic eruptions in 536, 540 and 547 AD, which was probably sustained by ocean and sea-ice feedbacks, as well as a solar minimum. We thus identify the interval from 536 to about 660 AD as the Late Antique Little Ice Age. Spanning most of the Northern Hemisphere, we suggest that this cold phase be considered as an additional environmental factor contributing to the establishment of the Justinian plague, transformation of the eastern Roman Empire and collapse of the Sasanian Empire, movements out of the Asian steppe and Arabian Peninsula, spread of Slavic-speaking peoples and political upheavals in China.
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| 2. |
- Büntgen, Ulf, et al.
(author)
-
Multi-proxy dating of Iceland's major pre-settlement Katla eruption to 822-823 CE
- 2017
-
In: Geology. - 0091-7613 .- 1943-2682. ; 45:9, s. 783-786
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Journal article (peer-reviewed)abstract
- Investigations of the impacts of past volcanic eruptions on climate, environment, and society require accurate chronologies. However, eruptions that are not recorded in historical documents can seldom be dated exactly. Here we use annually resolved radiocarbon (C-14) measurements to isolate the 775 CE cosmogenic C-14 peak in a subfossil birch tree that was buried by a glacial outburst flood in southern Iceland. We employ this absolute time marker to date a subglacial eruption of Katla volcano at late 822 CE to early 823 CE. We argue for correlation between the 822-823 CE eruption and a conspicuous sulfur anomaly evident in Greenland ice cores, which follows in the wake of an even larger volcanic signal (ca. 818-820 CE) as yet not attributed to a known eruption. An abrupt summer cooling in 824 CE, evident in tree-ring reconstructions for Fennoscandia and the Northern Hemisphere, suggests a climatic response to the Katla eruption. Written historical sources from Europe and China corroborate our proposed tree ring-radiocarbon-ice core linkage but also point to combined effects of eruptions occurring during this period. Our study describes the oldest precisely dated, high-latitude eruption and reveals the impact of an extended phase of volcanic forcing in the early 9th century. It also provides insight into the existence of prehistoric woodland cover and the nature of volcanism several decades before Iceland's permanent settlement began.
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| 3. |
- Büntgen, Ulf, et al.
(author)
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Reply to 'Limited Late Antique cooling'
- 2017
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In: Nature Geoscience. - : Springer Science and Business Media LLC. - 1752-0894 .- 1752-0908. ; 10:4, s. 243-243
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Journal article (other academic/artistic)
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| 4. |
- Büntgen, Ulf, et al.
(author)
-
SCIENCE IN SILENCE
- 2021
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In: Erdkunde. - : Erdkunde. - 0014-0015 .- 2702-5985. ; 75:1, s. 61-63
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Journal article (peer-reviewed)abstract
- Intellectual and cultural benefits from extended periods of self-isolation have a long history. The ongoing decline in academic freedom, however, distinguishes the coronavirus disease from previous crises. Despite the unprecedented political and economic challenges, as well as the devastating societal disruptions caused by the global COVID-19 pandemic, this study focusses on the fresh opportunities the current coronavirus restrictions offer to question extant academic models and paradigms, in the spirit of creating a more equitable and sustainable research system in the future.
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