Why Did the Vikings Abandon Their Most Successful Settlement in Greenland?

A new study argues that an extended drought, and not cold temperatures, drove the Norse settlers from the region

ruins of a gray and brown stone building on green landscape overlooking lake
Ruins of a Norse church in Greenland. Public domain via Wikimedia Commons under CC BY-SA 1.0

Scientists may have discovered why the Vikings abandoned their largest settlement on Greenland, reports David Hambling from the Guardian. Beginning in the 10th century, the Norse settlers resided in the colonies for more than 450 years before mysteriously disappearing sometime in the 1400s. Experts had long thought this was due to a dramatic shift in temperatures that brought about cold, inclement weather, making living conditions difficult, reports Colin Barras from Science.

Now new research published last month in Science Advances suggests that drought may have been the cause.

The Vikings’ Eastern Settlement in southern Greenland was established in 985 C.E., lasting to around 1450 C.E. At its peak, it contained a population of more than 2,000 inhabitants and was flush with green pastures for grazing livestock, according to CNN’s Ashley Strickland.

Scientists believed that the Little Ice Age, which cooled temperatures in the North Atlantic region between 1300 and 1850, made agriculture and farming in the region nearly impossible. However, the University of Massachusetts Amherst and University at Buffalo researchers argue in their study, that no actual evidence for this theory exists. They claim that the data used to support the idea that cold temperatures drove out the Vikings was taken from ice core collections from more than 600 miles north of the settlement and some 6,500 feet higher in elevation. Additionally, it was highly unlikely that temperatures had fluctuated much in the area the Norse settled during that time, according to a UMass Amherst statement.

"Before this study, there was no data from the actual site of the Viking settlements. And that's a problem," says study coauthor Raymond Bradley, a UMass Amherst geosciences professor, in the statement. "We wanted to study how climate had varied close to the Norse farms themselves."

The team spent three years collecting soil samples from Lake 578, which is near the location of the largest farm groupings in the Eastern Settlement. By analyzing their collections, they were able to paint a picture of the area’s climate record over the past 2,000 years.

To do this, the researchers checked the lake samples for markers that could help reconstruct what the climate may have been like at the settlement. Scientists first analyzed lipids within the soil, called BrGDGT, that are produced by bacteria and helpful in identifying historic temperatures, according to CNN. The second marker came from decaying plants and grasses, and the waxy coating on them, from which researchers can gather how dry it was at the time they were growing.

"Nobody has actually studied this location before," says lead study author Boyang Zhao, now a postdoctoral research associate at Brown University, in the statement. “What we discovered is that, while the temperature barely changed over the course of the Norse settlement of southern Greenland, it became steadily drier over time."

The Vikings made the most of harsh winters by supplementing low crop yields with food from the ocean and trading goods for dried fruits and wood, reports Science Alert’s Mike McRae. Norse farmers would have needed large supplies of dried grass to feed housed livestock during the frigid winter months. Even under normal conditions, come spring, livestock would have been too weak to move, requiring farmers to carry them back out to pasture to graze once the snow melted, per CNN.

Science Alert notes that Greenland’s already challenging conditions would have made a drought that much harder to survive. Remoteness and the difficulty to acquire food could have affected social ties and family size, and ivory walrus tusks (used to trade for dried fruits and timber with those back home) dropped in value as elephant ivory trade expanded.

According to Live Science’s Owen Jarus, most experts are supportive of the new finding. However, some raise questions over the team’s claim that the extended drought had a large impact on the settlement.

The research "does not demonstrate that the drying was on a scale which would have resulted in a significant reduction in utilizable biomass, so it remains to be shown to what extent the proposed drying trend could have been an actual problem for farming," Orri Vésteinsson, an archaeology professor at the University of Iceland not affiliated with the study, told Live Science in an email.

Kevin Smith, another expert and a senior research fellow at Brown University, who was also not involved in the study, tells Live Science that historical records indicate, between 1402 and 1404, an epidemic (likely the bubonic plague) spread throughout Iceland, killing nearly half the population. This may have tempted the Vikings to relocate to Iceland, where the conditions were "far better for the kind of farming they [the Norse] knew how to do."