Event
Younger Dryas
A return to cold climate about 12,900 to 11,700 years ago, at the end of the last Ice Age. The climate shift is real.
Illustration made for this site. Not a photograph of the claim.
A 2007 paper argued a comet or airburst set it off. Later work has not settled that cause. Hancock uses the cold snap as the moment a lost civilisation fell. The climate event is ground. The civilisation is a reading.