Extreme weather events of 535-536

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The extreme weather events of 535-536 were one of the most severe and protracted short-term episodes of cooling in the Northern Hemisphere in the last 2,000 years. The event is thought to have been caused by an extensive atmospheric dust veil, most likely resulting from a large volcanic eruption in the tropics.[1] Its effects were widespread, causing unseasonal weather, crop failures and famines worldwide.

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[edit] Documentary evidence

The Byzantine historian Procopius recorded of 536, in his 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." [2][3]

The Gaelic Irish Annals[4] [5] record the following:

Further phenomena reported by a number of independent contemporary sources:

  • Low temperatures, even snow during the summer (snow reportedly fell in August in China [6], which postponed the harvest there)
  • Crop failures[7]
  • "A dense, dry fog" in the Mideast, China, and Europe [8]
  • Drought in Peru, which affected the Moche culture [9][10]

[edit] Scientific evidence

Tree ring analysis by dendrochronologist Mike Baillie, of the Queen's University of Belfast, shows abnormally little growth in Irish oak in 536 and another sharp drop in 542, after a partial recovery.[citation needed] Similar patterns are recorded in tree rings from Sweden and Finland, in California's Sierra Nevada and in rings from Chilean Fitzroya trees.[citation needed] Ice cores from Greenland and Antarctica show evidence of substantial sulphate deposits around AD 533-534 ± 2 years, evidence of an extensive acidic dust veil.[1] Recent re-analysis of Greenland and Antarctic ice cores by Larsen et al. supports the latter explanation; the authors comment that the evidence of sulphate deposits in the ice indicates "a large explosive, near equatorial volcanic eruption, causing widespread dimming and contributing to the abrupt cooling across much of the Northern Hemisphere".[1]

[edit] Possible explanations

It has been conjectured that these changes were due to ashes or dust thrown into the air after the impact of a comet[11] or meteorite,[12][13] or after the eruption of a volcano (a phenomenon known as "volcanic winter").[14] The evidence of sulphate deposits in ice cores strongly support the volcano hypothesis; the sulphate spike is even more intense than that which accompanied the lesser episode of climatic aberration in 1816, popularly known as the "Year Without a Summer", which has been connected to the explosion of the volcano Tambora in Sumbawa, Indonesia.[1]

In 1984, R. B. Stothers postulated that this event may have been caused by the volcano Rabaul in what is now Papua New Guinea. [15]

In 1999, David Keys in his book Catastrophe: A Quest for the Origins of the Modern World (supported by work of the American volcanologist Ken Wohletz), suggested that the Indonesian volcano Krakatoa exploded at the time and caused the changes.[14] It is suggested that an eruption of Krakatoa attributed to the year 416 by the Javanese Book of Kings actually took place at this time – there is no other evidence of such an eruption in 416.[citation needed]

[edit] Historic consequences

The 536 event and ensuing famine has been suggested as an explanation for the Dark Age fact that Scandinavian elites sacrificed large amounts of gold at the end of the Migration Period, possibly to appease the angry gods and get the sunlight back.[16]

The decline of Teotihuacán, a huge city in Mesoamerica, is also correlated with the droughts related to the climate changes, with signs of civil unrest and famines.

David Keys' book speculates that the climate changes may have contributed to various developments, such as the emergence of the Plague of Justinian, the decline of the Avars, the migration of Mongolian tribes towards the West, the end of the Persian empire, the rise of Islam and the fall of Teotihuacán. In 2000, a 3BM Television production (for WNET and Channel Four) capitalized upon Key's book. This documentary, under the name Catastrophe! How the World Changed, was broadcast in the U.S. as part of PBS's Secrets of the Dead series. However, Keys and Wohletz' ideas are not widely accepted at this point.[citation needed]

[edit] See also

[edit] Further reading

[edit] Notes

  1. ^ a b c d Larsen, L. B., et al. (2008), "New ice core evidence for a volcanic cause of the A.D. 536 dust veil", Geophys. Res. Lett., 35, L04708, doi:10.1029/2007GL032450.
  2. ^ Climate, by George Ochoa, Jennifer Hoffman, and Tina Tin (published as a book in 2005 by Rodale Books Intl.), gives this quote as "The Sun gave forth its light without brightness, like the moon during this whole year, and it seemed exceedingly like the Sun in eclipse".
  3. ^ Procopius, History of the Wars, Books III and IV: The Vandalic War, translated by H. B. Dewing, [1].
  4. ^ Gaelic Irish Annals translations
  5. ^ Documents of Ireland
  6. ^ Climate, by George Ochoa, Jennifer Hoffman, and Tina Tin (published as a book in 2005 by Rodale Books Intl.), page 71
  7. ^ See Rosen, William, Justinian's Flea.
  8. ^ Climate, by George Ochoa, Jennifer Hoffman, and Tina Tin (published as a book in 2005 by Rodale Books Intl.), page 71
  9. ^ Climate, by George Ochoa, Jennifer Hoffman, and Tina Tin (published as a book in 2005 by Rodale Books Intl.), page 71
  10. ^ Keys, David, Catastrophe: A Quest for the Origins of the Modern World, Ballantine Books, New York, 1999.
  11. ^ MacIntyre, Ferren (2002) "Simultaneous Settlement of Indo-Pacific Extrema?" Rapa Nui Journal 16#2: 96-104
  12. ^ Baillie, Mike, Exodus to Arthur: Catastrophic Encounters With Comets, 1999, ISBN 0-7134-8352-0
  13. ^ Rigby, Emma, Melissa Symonds and Derek Ward-Thompson, ‘A comet impact in AD536?’, Astronomy and Geophysics, 45 (February 2004) [2]
  14. ^ a b Wohletz, Ken, Were the Dark Ages Triggered by Volcano-Related Climate Changes in the 6th Century?
  15. ^ R. B. Stothers - "Mystery cloud of AD 536" in Nature 307, 344 - 345 (26 January 1984); doi:10.1038/307344a0
  16. ^ Morten Axboe: "Året 536" Skalk (2001:4) 28-32

[edit] External links