I find the traditional account of the Norse settlement of Greenland, of farmers and herdsmen coming to the island on the advice of Erik the Red, struggling to make a living, and gradually declining over the centuries, strangely appealing. It is a tragic story of deception, fighting against the odds, and the ultimate triumph of nature over man. On reflection, though, the account doesn't match what most historians (and, I think, most people) know about overseas colonization: people rarely undertake something so dangerous, certainly not for hundreds of years at a time, without the promise of profitable returns.
Archaeologists have long known, thanks to Norse artifacts found in Native American sites, that the Greenlanders weren't just isolated farmers. They certainly traded with their Inuit neighbors and had at least one post on Helluland (Baffin Island) in the fourteenth century. Thomas McGovern now argues that the Norse came to Greenland for commercial reasons – specifically, to harvest walrus tusks, one of medieval Europe's primary sources of ivory. Walrus proved hard to come by: it took a month of hard rowing to reach and return from the prime breeding grounds in Disko Bay (latitude 69 degrees N). But significant rewards came to those who made the effort: 520 tusks, extracted from 260 rotting walrus heads, “had the same value as 780 cows or 60 tons of fish.”*
McGovern also believes economic change, not climate change, killed the colony in the fourteenth century. Ivory belonged to Europe's elite, “prestige-good” economy, but around 1250 CE Europe's merchants began shifting from prestige goods to staple goods, like food and wool. Prices for ivory fell, and then plummeted when the Black Death (1346-50) killed off the Greenlanders' customers. Perhaps the Norse colony might have recovered later, but the Little Ice Age made Disko Bay increasingly inaccessible to small craft. Between 1364 and 1409 the surviving Norse abandoned their settlements as unprofitable, and left Greenland to the people who had actually come there to settle permanently: the Inuit.
* I've not been able to find current equivalents for these, but during the second half of the eighteenth century, colonial American merchants charged 15-20 GBP per ton of fish. (James Lydon, "Fish and Flour for Gold," Program in Early American Economy and Society, Library Co. of Philadelphia , p. 79.)
(Above image, of Disko Bay, courtesy of Algkalv and Wikimedia Commons.)