It seems obvious that human civilization would die back during the glacial period, and then begin to flourish during the warm Holocene interglacial that followed, starting some 12000 years ago. It’s funny that the Climate Change crowd doesn’t understand this.
Population and life in general tends to thrive during Earth warm episodes, and tend to diminish during the cold ones.
Population in Europe obviously died out over the huge area covered by glaciers, but even the adjacent areas of western, central and southern Europe were so cold, that humans could not live there.