Er, did you read that, before posting the link - It rather supports the idea that the climate has always changed, leading to the rise and fall of civilisations.
Quote from the link:
"After all, it was when weather patterns finally became predictable about 11,500 years ago that complex civilizations finally formed in the first place. A stable climate ensured that crops would grow year after year, and a reliable source of food freed people to settle down and develop culture."
And Greenlands ice sheet was particularly stable: