The article suggests that this may have in part been due to the falling sea levels. Europe extended much further to the North to the point that Great Britain wa

The article suggests that this may have in part been due to the falling sea levels. Europe extended much further to the North to the point that Great Britain was surrounded by land. The gap between Europe and Africa was also close enough to allow for much easier crossings. Early humans were likely always somewhat migratory animals as there was no way to preserve food for longer periods - grain agriculture was what allowed for permanent settlements and bureaucracy (i.e. long-term planning and resource allocation). They may have tended to the local vegetation because they would likely return in the future but it seems obvious that they'd also be on the lookout for new places while keeping track of known good spots in the past - even elephants travel between distant "watering holes". In other words: it wasn't the cold that was the problem, it was the availability of resources, i.e. food. If the accessible parts of Europe had sufficient food to make them attractive for foraging and hunting, humans would eventually make the crossing and decide to stay and eventually move further into the continent. Note that we're not talking about events that happened over human lifetimes - the North Sea didn't drain overnight. Maybe a visual aid helps. Try to find Europe on this map. Hint: look for mountains that look like familiar coastlines: https://en.wikipedia.org/wiki/File:Global_sea_levels_during_the_last_Ice_Age.jpg https://en.wikipedia.org/wiki/File:Global_sea_levels_during_...