As human beings displace large predators they create breaks in the breeding ranges. That in turn leads to genetic isolation and each small group of predators begin to exhibit variations in their MtDNA.
It turns out that it's quite easy to figure out when the bears disappeared simply by counting the remains in caves AND by checking their MtDNA to see if they were part of a genetically isolated population.
Europeans have done the same with human remains in Western and Northern Europe and demonstrated the existence of the Ice Age human refugia near the French/Spanish border. They tracked the Sa'ami North, then East around the residual Scandinavian Ice Lobe and then South just checking "remains".
A couple of things you have to recall about the last Ice Age is that it was immediately followed by the Younger Dryas. This is a climate anomaly ~ the current proposal (with much evidence) is that a comet hit the residual ice lobe in North America (in Canada). This broke it up and plugged the St. Lawrence. That reduced the incidence of freshwater reaching the North Atlantic, the Atlantic Conveyor stopped, and Europe froze again. Otherwise, this event occurred entirely within the time of the current INTERGLACIAL which is rapidly coming to an end having "peaked" with several spikes in the last thousand years. That BTW is typical of ALL the preceeding 20+ Ice Ages.
Within the range of the previous Ice Age there were several Interstadials ~ which are warm periods of LESS THAN 10,000 years ~ that affected North America, or Asia, or Europe, or South America, at different times in different areas.
Our brand of humanity managed to penetrate Central Asia during an Interstadial there about 50,000 years ago. An interstadial that affected Europe and Asia North of the Himalayas about 35,000 years ago allowed our brand of people to move into Europe and near China. 15,000 years ago the current Interglacial began and our brand of people moved on into the Chinese Plains, Siberia, etc, and into most of Europe, West Asia, Middle East, etc.
So, what about these bears? Well, there was a PEAK in the glaciation at about 20,000 years ago. That put a crimp in everybody's trick! Before all that modern human radiation into East Asia and Europe it got really cold, lots of ice and snow came, and it happened everywhere in the latitudes affected by the great glaciers.
So, whatever human beings were up to 35,000 years ago, that was interrupted by what happened 20,000 years ago, and then 15000 years ago everything changed again. About 11,000 years ago that doggone comet hit and it was back to square one for another 1500 years, particularly in North America and Europe.
Humanity barely hung on during that period ~ the European Brown Bear didn't have a chance.
Great read on your post, lots of info. Thanks
Also, one has to suspect that a hibernating bear would be a tempting package of protein for a hungry human with a spear....
If I recall correctly, the comet was around 13,000 years ago, the younger Dryas around 11,000 ya. Actually, the comet may have caused a surge of fresh water thus changing the North Atlantic Deep Water circulation and bringing on the cold. Actually concentrated salt when ice freezes in the north is what keeps it going. In fact, a big danger if the Arctic ice melts in the summer is that fresh water will be increased in the North Atlantic, slowing NADW and causing severe winters in Britain and Europe.