Probability Stack

From Why Did Greenland’s Vikings Vanish? by Tim Folger. The traditional explanation is that the European Viking settlers were inadequate in making adjustments to their technology and folkways in order to accommodate the different Greenland environment.

Folger reports on recent archaeological finds which indicate that the Viking settlers in fact adjusted their folkways almost immediately on settlement and that the adjustments made were similar to those of the later Inuit settlers. It now appears that the Viking settlers were not simply farmers. They did farm but from the very beginning they also supplemented their diet with seal.

They hunted walrus for ivory to trade with Scandinavia and Europe. One adaptation involved division of labor. The walrus hunting season coincides with the short farming season. It appears that men and women ran the farm together but with women minding the farm while the men hunted seal in the spring and walrus during the summer.

How profitable was the ivory trade? Every six years, the Norse in Greenland and Iceland paid a tithe to the Norwegian king. A document from 1327, recording the shipment of a single boatload of tusks to Bergen, Norway, shows that that boatload, with tusks from 260 walruses, was worth more than all the woolen cloth sent to the king by nearly 4,000 Icelandic farms for one six-year period.

[snip]

When the Norse arrived in Greenland, there were no locals to teach them how to live. “The Scandinavians had this remarkable ability to colonize these high-latitude islands,” says Andrew Dugmore. “You have to be able to hunt wild animals; you have to build up your livestock; you have to work hard to exist in these areas....This is about as far as you can push the farming system in the Northern Hemisphere.”

And push it they did. The growing season was short, and the land vulnerable to overgrazing. Ian Simpson has spent many seasons in Greenland studying soil layers where the Vikings farmed. The strata, he says, clearly show the impact of their arrival: The earliest layers are thinner, with less organic material, but within a generation or two the layers stabilized and the organic matter built up as the Norse farmwomen manured and improved their fields while the men were out hunting. “You can interpret that as being a sign of adaptation, of them getting used to the landscape and being able to read it a little better,” Simpson says.

So, if not maladaptation, then what?

For all their intrepidness, though, the Norse were far from self-sufficient, and imported grains, iron, wine and other essentials. Ivory was their currency. “Norse society in Greenland couldn’t survive without trade with Europe,” says Arneborg, “and that’s from day one.”

Then, in the 13th century, after three centuries, their world changed profoundly. First, the climate cooled because of the volcanic eruption in Indonesia. Sea ice increased, and so did ocean storms—ice cores from that period contain more salt from oceanic winds that blew over the ice sheet. Second, the market for walrus ivory collapsed, partly because Portugal and other countries started to open trade routes into sub-Saharan Africa, which brought elephant ivory to the European market. “The fashion for ivory began to wane,” says Dugmore, “and there was also the competition with elephant ivory, which was much better quality.” And finally, the Black Death devastated Europe. There is no evidence that the plague ever reached Greenland, but half the population of Norway—which was Greenland’s lifeline to the civilized world—perished.

The Norse probably could have survived any one of those calamities separately. After all, they remained in Greenland for at least a century after the climate changed, so the onset of colder conditions alone wasn’t enough to undo them. Moreover, they were still building new churches—like the one at Hvalsey—in the 14th century. But all three blows must have left them reeling. With nothing to exchange for European goods—and with fewer Europeans left—their way of life would have been impossible to maintain. The Greenland Vikings were essentially victims of globalization and a pandemic.

That last sentence is an odd summary of the preceding evidence. Explicitly, the "Greenland Vikings were essentially victims of" climate change, "globalization and a pandemic."

As an aside, the global climate change advocates have always been reluctant to address that there has been, even within historical times but long before CO2 emitting industrialization, dramatic climate change. This is an instance of that journalistic misdirection which is so irritating to the critical reader.

Climate change, globalization, and pandemics. There is one further element that might have contributed to the disappearance of the Greenland Vikings.

The Norse, he says, were especially vulnerable to sudden death at sea. Revised population estimates, based on more accurate tallies of the number of farms and graves, put the Norse Greenlanders at no more than 2,500 at their peak—less than half the conventional figure. Every spring and summer, nearly all the men would be far from home, hunting. As conditions for raising cattle worsened, the seal hunts would have been ever more vital—and more hazardous. Despite the decline of the ivory trade, the Norse apparently continued to hunt walrus until the very end. So a single storm at sea could have wiped out a substantial number of Greenland’s men—and by the 14th century the weather was increasingly stormy. “You see similar things happening at other places and other times,” McGovern says. “In 1881, there was a catastrophic storm when the Shetland fishing fleet was out in these little boats. In one afternoon about 80 percent of the men and boys of the Shetlands drowned. A whole bunch of little communities never recovered.”

An interesting article.

This fits into a line of thinking I have been pursuing recently regarding determinants of life outcomes. What makes success happen?

That's a long conversation but one aspect is having the right ingredients of success. Scott Adams refers to this as the skill stack. His hypothesis is that in a complex society with great specialization of labor, any particular job or vocation is dependent on a range of skills that have to occur in the right proportions, at the right time, in the right sequence. In his instance, it was insufficient to have a modicum of drawing skills, or a dry sense of humor, or plenty of material. He needed all three to occur and occur in the right mix and right order.

I have expanded the idea beyond the career frame to a life perspective. Over the course of a life, what are the constituent elements of success? With a hat tip to Adams, I have called this a Capability Stack. The determinants of your life outcomes are dependent, I suspect, on at least six capabilities: physical capabilities, cognitive capabilities, social capabilities (ability to interact with others), personal capabilities (psychological and experiential), cultural capabilities (values, goals, and knowledge from your culture), and contextual capability (circumstances in which you are embedded). This Capability Stack shapes your outcomes.

The experience of the Greenland Vikings suggests another Stack perspective - the Probability Stack. You might also refer to it as a Fragility Stack.

What Folger is suggesting is that the Greenland Vikings were highly adaptive and successful but that their successful outcomes were fragile. In order for their economic/social system to work, many things had to go right in the right order. Some of which were beyond their direct control.

They had to have the social cohesion and organizational capabilities to share work between the sexes, and among many people. The growing seasons and hunting seasons had to be stable. The weather needed to be mild. There had to be a market for their luxury goods. There had to be a source for trade to supply the essentials they could not produce. Their population had to be sufficiently large to sustain themselves over fluctuations due to natural ravages but small enough not to over stress the ecology.

Each of these elements had a probability of occurring. Things went well when the probabilities for all the elements were sufficiently high.

Collapse occurred when the probabilities of some elements in the stack dropped below a critical level. One bad storm, some prolonged disruption in trade supplies or routes, one collapse in markets, one change in the climate, etc.

The system was successful within its parameters but given the circumstances of the day (trade systems, technology, customs, etc.), the system was complex and therefore also fragile. It worked when the stars aligned and failed when they came out of alignment with one another.