Here is the meat and potatoes of this sparse meal:
“The kind of evidence we are finding does suggest that climate change at the end of the last Ice Age was the result of a catastrophic event,” said study team member Ken Tankersley, an anthropologist at the University of Cincinnati.”
See, comets are external forces and not natural processes so that explains why all climate change of a similar order must be caused by some aggravating agent.
Cataclysmic comet climatic catalyst.