Volcanic winter of 536

Documentary evidence

The Roman historian Procopius recorded in his AD 536 report on the wars with the Vandals: "during this year a most dread portent took place. For the sun gave forth its light without brightness... and it seemed exceedingly like the sun in eclipse, for the beams it shed were not clear".

In 538, the Roman statesman Cassiodorus described the following to one of his subordinates in letter 25:

• The sun's rays were weak, and they appeared a "bluish" colour.
• At noon, no shadows from people were visible on the ground.
• The heat from the sun was feeble.
• The moon, even when full, was "empty of splendour"
• "A winter without storms, a spring without mildness, and a summer without heat"
• Prolonged frost and unseasonable drought
• The seasons "seem to be all jumbled up together"
• The sky is described as "blended with alien elements" just like cloudy weather, except prolonged. It was "stretched like a hide across the sky" and prevented the "true colours" of the sun and moon from being seen, along with the sun's warmth.
• Frosts during harvest, which made apples harden and grapes sour.
• The need to use stored food to last through the situation.
• Subsequent letters (nos. 26 and 27) discuss plans to relieve a widespread famine.

In the entry corresponding to the year 535–536, the early 7th century Mandaean Book of Kings relates: "were you to request a tenth of a peck of grain in the land Gawkāy, for five staters, we would look but it would not be found." In other words, if 873 grams of grain could not even be purchased for 43 grams of gold, then grain was extremely scarce.

Michael the Syrian (1126–1199), a patriarch of the Syriac Orthodox Church, reported that from 536 to 537 the sun shone feebly for a year and a half.

The Irish annals recorded the following:

• "A failure of bread in AD 536" – the Annals of Ulster
• "A failure of bread from AD 536–539" – the Annals of Inisfallen

The mid-10th-century Annales Cambriae record for the year 537:

• "The Battle of Camlann, in which Arthur and Medraut fell, and there was great mortality in Britain and Ireland."

Chinese sources include:

• The Annals of the Tang Dynasty, which mentions the "great cold" and "famine" that occurred in 536.
• The Zizhi Tongjian, a historical text that mentions the "great cold" and the "famine that occurred in the summer."
• The Nan Shi 南史 (History of the South), which describes "a yellow ash-like substance from the sky".

Further phenomena were reported by independent contemporary sources:

• Low temperatures, even snow during the summer (snow reportedly fell in August in China, which caused the harvest there to be delayed).
• Widespread crop failures.
• "A dense, dry fog" in the Middle East, China and Europe.
• Drought in Peru, which affected the Moche culture.

There are other sources of evidence regarding this period.

Scientific evidence

Tree ring analysis by the dendrochronologist Mike Baillie, of Queen's University Belfast, Ireland, shows abnormally little growth in Irish oak in 536 and another sharp drop in 542, after a partial recovery. Ice cores from Greenland and Antarctica show evidence of substantial sulfate deposits in around 534 ± 2, which is evidence of an extensive acidic dust veil.

Possible explanations

It was originally theorized that the climatic changes of AD 536 were caused by either volcanic eruptions (a phenomenon known as "volcanic winter") or impact events (meteorite or comet).

In 2015, revision of polar ice core chronologies dated sulfate deposits and a cryptotephra layer to the year 536 (previously dated to 529 before revision). This is strong evidence that a large explosive volcanic eruption caused the observed dimming and cooling. But Dallas Abbott and her colleagues found spherules containing nickel and copper in an ice core, giving support to an impact event around this time.

The source of volcanic eruption remains to be found but several proposed volcanoes have been rejected:

• R. B. Stothers postulated the volcano Rabaul in New Britain, in Papua New Guinea. The eruption is now thought to have occurred in the interval AD 667–699 based on wiggle-match radiocarbon dating.

• David Keys suggested the volcano Krakatoa by shifting a cataclysm in AD 416 recorded in the Javanese Book of Kings to 535. Drilling projects in the Sunda Strait ruled out any possibility that an eruption took place there during this time period.

• Robert Dull and colleagues proposed the large VEI-7, Tierra Blanca Joven (TBJ) eruption of the Ilopango caldera. Identification of TBJ tephra in ice cores narrowed the eruption date to 429–433.

• Christopher Loveluck and his colleagues proposed Icelandic volcanos based on the shards from a Swiss glacier. However, the cryptotephras dated exactly to AD 536 are geochemically distinct from Icelandic tephra, and the shards in the Swiss glacier have large age uncertainty.

Geochemical analysis of AD 536 cryptotephras distinguishes at least three synchronous eruptive events in North America. Further analysis correlates one of the eruptions to a widespread Mono Craters tephra identified in northeast California. The other two eruptions most likely originated from the eastern Aleutians and Northern Cordilleran volcanic province.

Historic consequences

Main article: Late Antique Little Ice Age

The 536 event and ensuing famine have been suggested as an explanation for the deposition of hoards of gold by Scandinavian elites at the end of the Migration Period. The gold was possibly a sacrifice to appease the gods and get the sunlight back. Mythological events such as the Fimbulwinter and Ragnarök are theorised to be based on the cultural memory of the event.

A book written by David Keys speculates that the climate changes contributed to various developments, such as the emergence of the Plague of Justinian (541–549), the decline of the Avars, the migration of Mongol tribes towards the west, the end of the Sasanian Empire, the collapse of the Gupta Empire, the rise of Islam, the expansion of Turkic tribes, and the fall of Teotihuacan. In 2000, a 3BM Television production (for WNET and Channel Four) capitalised upon Keys' book. The documentary, under the name Catastrophe! How the World Changed, was broadcast in the US as part of PBS's Secrets of the Dead series.

However, Keys and Wohletz's ideas lack mainstream acceptance. Reviewing Keys' book, British archaeologist Ken Dark commented that "much of the apparent evidence presented in the book is highly debatable, based on poor sources or simply incorrect. . . . Nonetheless, both the global scope and the emphasis on the 6th century CE as a time of wide-ranging change are notable, and the book contains some obscure information that will be new to many. However, it fails to demonstrate its central thesis and does not offer a convincing explanation for the many changes discussed".

Philologist Andrew Breeze argues that some Arthurian events, including the Battle of Camlann, are historical, happening in 537 as a consequence of the famine associated with the climate change of the previous year.

Historian Robert Bruton argues that this catastrophe played a role in the decline of the Roman Empire.{{cite book|url=https://www.academia.edu/42765814|title=The Role of Climate Change in the Decline of the Roman Empire

Notes

References

References

1. Abbott, D. H.. (December 2008). "Magnetite and Silicate Spherules from the GISP2 Core at the 536 A.D. Horizon".
2. (2017). "The Fate of Rome". Princeton University Press.
3. (2020). "Climate and social change at the start of the Late Antique Little Ice Age". The Holocene.
4. (15 November 2018). "Why 536 was 'the worst year to be alive'". Science.
5. (1916). "Procopius". William Heinemann.
6. (2005). "Climate: the force that shapes our world and the future of life on earth". Rodale.
7. (1886). "The Letters of Cassiodorus". Henry Frowde.
8. (2022). "The Book of Kings and the Explanations of This World". Liverpool.
9. (1901). "Chronique de Michel le Syrien, Patriarche Jacobite d'Antoche". Leroux.
10. [http://www.ucc.ie/celt/publishd.html Gaelic Irish Annals] translations
11. "List of Published Texts at CELT".
12. "Annals of the Four Masters".
13. "Camlan {{!}} Robbins Library Digital Projects".
14. (2005). "Climate: the force that shapes our world and the future of life on earth". Rodale.
15. Rosen. (2007). "Justinian's flea: Plague, Empire and the Birth of Europe". Jonathan Cape.
16. Keys, David Patrick. (2000). "Catastrophe: an investigation into the origins of the modern world". Ballantine Pub.
17. (1983). "Volcanic eruptions in the Mediterranean before AD 630 from written and archaeological sources". Journal of Geophysical Research.
18. (16 January 1984). "Mystery cloud of AD 536". Nature.
19. (1988). "Volcanic winters". Annual Review of Earth and Planetary Sciences.
20. (2005). "The mystery cloud of 536 CE in the Mediterranean sources". Dumbarton Oaks Papers.
21. Baillie, M. G. L. (1994). "Dendrochronology Raises Questions About the Nature of the AD 536 Dust-Veil Event." ''[[The Holocene (journal). The Holocene]],'' fig. 3, p. 215.
22. (2008). "New ice core evidence for a volcanic cause of the A.D. 536 dust veil". Geophys. Res. Lett..
23. Baillie. (1999). "Exodus to Arthur: Catastrophic Encounters with Comets". B.T. Batsford.
24. (February 2004). "A comet impact in AD 536?". Astronomy and Geophysics.
25. MacIntyre, Ferren. (2002). "Simultaneous Settlement of Indo-Pacific Extrema?". Rapa Nui Journal.
26. (2015). "Timing and climate forcing of volcanic eruptions for the past 2,500 years". Nature.
27. (2014-09-01). "Volcanism, Impacts, and Mass Extinctions: Causes and Effects".
28. (Jan 15, 2014). "AD 536: The year that winter never ended". New Scientist.
29. Stothers. (26 January 1984). "Mystery cloud of CE 536". Nature.
30. (2015-07-04). "A revised age of ad 667–699 for the latest major eruption at Rabaul". Bulletin of Volcanology.
31. (2013-02-09). "Planktonic Foram Dates from the Indonesian Arc: Marine 14C Reservoir Ages and a Mythical AD 535 Eruption of Krakatau". Radiocarbon.
32. Dull. (13–17 December 2010). "Did the TBJ Ilopango eruption cause the AD 536 event?". AGU Fall Meeting Abstracts.
33. (October 2019). "Radiocarbon and geologic evidence reveal Ilopango volcano as a source of the colossal 'mystery' eruption of 539/40 CE". Quaternary Science Reviews.
34. (20 October 2020). "The magnitude and impact of the 431 CE Tierra Blanca Joven eruption of Ilopango, El Salvador". Proceedings of the National Academy of Sciences.
35. (2018-11-14). "Alpine ice-core evidence for the transformation of the European monetary system, CE 640–670". Antiquity.
36. "Why 536 was 'the worst year to be alive'".
37. (2020-06-08). "Smoking guns and volcanic ash: the importance of sparse tephras in Greenland ice cores". Polar Research.
38. (2023-02-01). "The significance of volcanic ash in Greenland ice cores during the Common Era". Quaternary Science Reviews.
39. (2022-01-18). "No evidence for tephra in Greenland from the historic eruption of Vesuvius in 79 CE: implications for geochronology and paleoclimatology". Climate of the Past.
40. Axboe. (2001). "Året 536". Skalk.
41. Axboe. (1999). "The year 536 and the Scandinavian gold hoards". [[Medieval Archaeology (journal).
42. Ström, Folke: ''Nordisk Hedendom'', [[Studentlitteratur]], Lund 2005, {{ISBN. 91-44-00551-2 (first published 1961) among others, refer to the climate change theory.
43. Gunn, Joel D.. (2000). "The Years Without Summer: Tracing A.D. 536 and its Aftermath". Archaeopress.
44. Dark, Ken. (November 1999). "Jumbling old events with modern myths". British Archaeology.
45. Breeze, Andrew. (2020). "British Battles 493–937: Mount Badon to Brunanburh". Anthem Press.
46. (2006). "The 1452 or 1453 A.D. Kuwae Eruption Signal Derived from Multiple Ice Core Records: Greatest Volcanic Sulfate Event of the Past 700 Years". Journal of Geophysical Research.