I also personally think that France's demographic situation in the early 1300s was a perfect example of Malthus's law, there were too many people compared to what the land could provide at that time (given the available technology). Some areas in the Southern Alps (Alpes-Maritimes) were never to be inhabited again after that.
> Some areas in the Southern Alps (Alpes-Maritimes) were never to be inhabited again after that.
But that might also be due to the end of the warm period and the start of the little ice age. For reference: Its about now that the norse have to abandon their Greenland settlement.
Note that most historians do not believe that the end of the Medieval warm period was the trigger of the collapse of the Greenland settlement, but rather that was the abandonment of trade routes to Greenland that caused its collapse.
I still think that the changing temperature was likely a factor but perhaps just a small one. It certainly would have got harder to eek out an existence on the island.
As you say though a bigger factor was Portuguese traders gaining access to African elephant ivory which was easier and cheaper to procure than walrus ivory which was the cash crop of the Greenland settlement.
