I guess the next question is did the plunge into the last ice age come as quickly? That would make the climate in the Northern Hemisphere go very bad very fast.
There’s probably literally zero data on that — not only is there probably zero known data, there’s probably nothing left to find. Of course, that assumes that glaciation has a gradualist cause, and I’m not of that view.
Tonight I picked up a DVD of a History Channel show, “10,000 BC”, which I’ve not yet watched, but the cover says something about a comet impact, so I’m in gleeful anticipation now. ;’)