The Cycle of Cosmic Catastrophes:
Flood, Fire, and Famine
in the History of Civilization
by Richard Firestone,
Allen West, and
Simon Warwick-Smith
The final sentence on the post says that the change happened about 10,000 year ago. That would coincide with the end of the Younger Dryas, which was quite likely caused by the Comet crash(s) of 13,000 years ago. SC post your book.
The Cycle of Cosmic Catastrophes:
Flood, Fire, and Famine
in the History of Civilization
by Richard Firestone,
Allen West, and
Simon Warwick-Smith
