Jared Diamond has postulated this theory too about the Norse not being able to sustain themselves in Greenland. This theory has several problems. One is that Jared Diamond based the section of his book Collapse on two sites in Greenland. The research was only focused on what they found in the trash dumps of these Norse sites. The scientists did not find fish or sea mammal bones in the trash. While this could be evidence that they didn’t hunt seals, walrus, whales or fish, and foolishly tried to sustain sheep and cows in Greenland. Findings from two trash dumps is certainly not conclusive.

The reason why this is even more inconclusive is that the Norse have a very deep maritime tradition. They do hunt whales and seals even to this day in the Faroe Islands. In the Icelandic sagas there are several specific chapters where Norse picked certain bays and fjords in iceland specifically for the fishing. So while it is clear that the Norse did not sustain their colony in Greenland, the theory that they foolishly clung to western/european ways is probably not completely accurate.