Climate changes of 535-536

In the years 535 and 536, several remarkable changes in world climate took place. The following were reported by a number of independent contemporary sources:

• low temperatures, even snow during the summer
• dark clouds, only few hours of sunlight during the day
• floods in formerly dry regions
• crop failures

It has been conjectured that these changes were due to ashes or dust thrown into the air after the impact of a comet or meteorite, or after the eruption of a volcano. A similar episode had been observed in 1816, the Year Without A Summer.

In a 1999 book, David Keys, supported by work of the American volcanologist Ken Wohletz, suggested that the Indonesian volcano Krakatau exploded at the time and caused the changes. He further speculated that the climate changes may have contributed to various important developments, such as the emergence of bubonic plague, the migration of Mongolian tribes towards the West, the end of the Persian empire, the rise of Islam and the end of various civilizations in Central and South America. These ideas are not widely accepted at this point.

Further Reading

• David Keys: Catastrophe: A Quest for the Origins of the Modern World, Ballentine Books, New York, 1999
• Ken Wohletz: Were the Dark Ages Triggered by Volcano-Related Climate Changes in the 6th Century?