Ancient Greenland mystery has a simple answer, it seems

Did the Norse colonists starve? Were they wiped out by the Inuit – or did they intermarry? No. Things got colder and they left.

A shipload of visitors arrived in the fjord overnight, so Ingibjorg Gisladottir dressed like a Viking and headed out to work in the ruins scattered along the northern edge of this tiny farming village.

Qassiarsuk is tiny (population: 56), remote, and short on amenities (no store, public restrooms, or roads to the outside world), but some 3,000 visitors come here each year to see the remains of Brattahlid, the medieval farming village founded here by Erik the Red around the year 985.

When they arrive, Ms. Gisladottir, an employee of the museum, is there to greet them in an authentic hooded smock and not-so-authentic rubber boots. "There were more visitors this year than last," she says. "People want to know what happened to the Norse."

The Greenland Norse colonized North America 500 years before Christopher Columbus "discovered" it, establishing farms in the sheltered fjords of southern Greenland, exploring Labrador and the Canadian Arctic, and setting up a short-lived outpost in Newfoundland.

But by 1450, they were gone, posing one of history's most intriguing mysteries: What happened to the Greenland Norse?

There are many theories: They were starved off by a cooling climate, wiped out by pirates or Inuit hunters, or perhaps blended into Inuit society as their own came unglued.

Now scientists are pretty sure they have the answer: They simply up and left.

"When the climate deteriorated, and their way of life became more difficult, they did what people have done throughout the ages: They looked for a more opportune place to live," says Niels Lynnerup, a forensic anthropologist at the University of Copenhagen in Denmark who studies the Norse.

Climate change was clearly driving the Norse, with their sheep- and cattle-farming traditions, to the edge of survival. With the onset of the Little Ice Age (from 1300 to 1850), conditions deteriorated across the Norse lands, particularly for people living on marginal farmland in Iceland, northern Norway, and Greenland.

Today, Greenland is warming up, with residents witnessing dramatic changes over the past five years. Winter sea ice, which the indigenous Inuit people in north Greenland traditionally relied on for sled dog transportation and seal hunting, has stopped forming reliably and robustly. Meanwhile, farmers in southerly communities like Qassiarsuk have enjoyed a markedly expanded growing area and season. Potatoes, previously confined to the far south, now grow as far north as the capital, Nuuk, 185 miles south of the Arctic Circle.

A slowly cooling climate in 1300s

In the late 1300s, Norse Greenlanders likely experienced this process in reverse, their farms squeezed by advan­cing glaciers and truncated summers. It's no accident, anthropologists say, that the cold-adapted Inuit were spreading south in this period, their hunting territory eventually overlapping with the Norse.

Scholars have wondered why the Norse failed to adapt, dropping agriculture in favor of hunting and fishing, like the Inuit. Turns out, they did – up to a point. An analysis of the bones of Norse buried at Brattahlid and other Norse sites found that early settlers ate a diet consisting of 80 percent agricultural products and 20 percent seafood; from the 1300s, the proportions reversed.

But there were limits to their adaptations. Archaeological excavations indicate that the Norse never adopted the harpoons, kayaks, and fishing gear their Inuit neighbors used so successfully. And while there are plenty of seal bones in Norse dumps, virtually no fish bones have been recovered, leading some to argue that they never took advantage of the ample fish resources in the streams and fjords, even in times of famine.

Gisladottir, a native of Iceland, scoffs at the notion, pointing out that Norse in other lands ate fish in quantity. "Of course they ate fish," she says. "One common way of preparing cod was to gut it, dry it, and then cook it in a pot for three or four hours and eat your porridge, bones and all."

Fish or no fish, the Norse collapse was apparently in slow motion.

Eva Panagiotakopulu, a paleoecologist at the University of Edinburgh, has put together what happened to two of the Norse's more northerly farms with the clues left behind by the flies, lice, and beetles that lived in their sod-walled houses. Although located on the same fjord, she says, the farms met different ends.

Insect species can be highly specialized, allowing scientists to determine what livestock were present (certain lice live only on sheep, others only on goats), whether a building was occupied (some flies could only survive winter inside heated homes), and where food (in the form of decaying meat) was present. Together, their remains provide a record of events on the farms.

Two farms, two different fates

"In one, everything was going fine until the very end, and then they abandoned it, taking their food and supplies with them," Ms. Panagiotakopulu says. "In the other, it seems the farmers were trapped in their house during a very long winter, ate their livestock, then their dog, and then died in their beds," prompting the flies to move from larder to bedroom.

Still, society apparently carried on: Some­body later removed and presumably buried the farmers' bodies.

Other sites also show an orderly abandonment, not an apocalyptic end.

"You don't find bodies in and around the ruins," says William Fitzhugh, director of the Arctic Studies Center at the Smithsonian Institution in Washington. "People are being properly buried in church graveyards right up into the 15th century, so it doesn't look like they were wiped out by marauding Inuit or other big disruptions."

Another indication of an orderly re­treat: no valuables such as crucifixes, chalices, or chandeliers at church sites, items often found in early medieval churches elsewhere in Scandinavia.

"Nothing has ever been found of any real value, just everyday items," says forensic anthropologist Lynnerup. "To me that indicates they left over an extended period."

Dr. Lynnerup's genetic studies of modern Inuit from across Greenland has put another theory to rest: that the Inuit absorbed the Norse. Their mitochondrial DNA (inherited from mothers only) show no European admixture. Archaeological evidence at medieval Inuit sites backs this up, suggesting contact between the two peoples was limited to minor barter.

"During the same time period, a lot of Norse settlements in Iceland and northern Norway were being abandoned, but nobody writes big books about that," Lynnerup says. "I'm not sure that the Norse saw Greenland as being very different from the fjords they came from in Norway, and leaving it was no more stressful than abandoning a hamlet in Norway." His theory: In the 1300s and 1400s, Greenland's youths voted with their feet, leaving until the colony could no longer support itself. The last few left.

"I imagine this old Norse man standing in his sodden, graying field with a couple of scrawny cattle and saying to his son, 'One day, this will all be yours,' " he says. "And the son gets on the next ship to Reykjavik."