I have developed an abiding interest the dawn of agriculture, and this idea certainly makes for fascinating pondering.
There is little doubt that a megaflood of glacial meltwater cascading off the North American continent into the Atlantic Ocean spurred the birth of agriculture and civilisation in the Middle East around 12,900 years ago. What was not known until recently is that this event, known as the Agassiz megaflood, may have been triggered by a comet exploding above or plunging into the ice sheet north of the modern Great Lakes.
According to two geologists at the University of Oregon, Dr Douglas Kennett and Dr Jon Erlandson, there is reason to believe a large chunk of a comet exploded above or crashed directly into the Laurentide ice sheet, rupturing the ice dams on the easterly margin of Lake Agassiz and causing frigid water to flood into the North Atlantic. [More]
I just ordered the book cited in the article: The First Farmers. Expect a review in a couple of weeks.
Or whenever I post the three others I have half finished.