Later on there was the "younger dryas event" which has been demonstrated to have been an anomaly caused by a comet that hit the residual Laurentide ice sheet.
From what I've read, it didn't actually hit because there's no sign of a direct impact, but was a very close encounter. It was supposed to have been extraterrestrial because the nanodiamonds found there could have been formed only through the extreme temperatures and pressures in something like an asteroid or comet impact. But the nanodiamond formation could just as likely have been the result of a long-lived, high-powered, auroral event with heavy arcing that occurred around that time. There exists
considerable archeological evidence worldwide of this event.
In the illustration below, are you saying that the initial warm-up and, therefore, beginning of the current interglacial, is that little rise in temperature right above the "st" in "Last" and not the large increase after that?
Just keep your eyes on ocean levels. There are several. We get a rise from an Antarctic meltdown as well as a North American/Eurasian meltdown.
There's a refreeze in the Northern Hemisphere called the "younger dryas". That lasts about 1500 years and then we get another, but smaller meltdown.
The "comet" definitely made a splashdown ~ and there are a number of other indicators, e.g. Canadian gold deposits in unglaciated Southern Indiana hills.