Graham Hancock’s theory suggests that the introduction of the moon into Earth’s orbit triggered the Younger Dryas, a sudden and extreme cooling period around 12,800 years ago. He proposes that the moon’s appearance caused massive environmental disruptions, possibly by shifting the planet’s axial tilt or impacting the atmosphere. This theory challenges mainstream explanations, such as comet impacts, and ties into his broader work on lost ancient civilizations and catastrophic events shaping human history.

You can explore his ideas further on his site or in his writings. https://grahamhancock.com/phorum/read.php?5,1306322