[OliverJones]

_Collapse_ and its author Jared Diamond get a mention in the article. This article adds a couple of factors to Diamond's. In 21st-century lingo the added factors were

-- Globalization: Elephant ivory from Africa, newly available, crowded out walrus-tusk ivory from the market. And Greenland's ivory sales were reduced in the wake of the plague. (Ivory was their foreign-exchange product.)

--Climate fluctuations, decades-long.

It's cool to learn a little more above the lived experience of those people. I imagine they argued with each other all the time about whether to spend their efforts getting stuff they could SELL or stuff they could USE. Figuring that out is hard enough for us, and we have perfect information about markets compared to them. Imagine how hard it must have been for them.

According to Diamond the Norse outposts in Greenland lasted five hundred years. That's a hundred years longer ago than the first English settlers clawed a foothold around Massachusetts Bay. A lot can happen in five hundred years! I suspect saying "it was this - " or "it was that - made them collapse" leads to gross oversimplification.