In the 10th Century, Erik the Red led Icelandic Vikings westward onto the pasturelands of southwestern Greenland, opening the way to the first European colony in the Americas a generation later. While the Norse settlement of North America was unsuccessful at the time, the livestock farmers of Greenland established a stable society of devout early Christians that flourished for the better part of 400 years. And then they vanished.

Contemplating this mysterious collapse, modern researchers have settled on two lines of thinking. First, the Norse were victims of abrupt climate change — the sudden onset of the medieval “Little Ice Age” that choked off their fjords and spread the ice cap over their grasslands. Second, they were victims of their own culture — unable to adapt their rigidly conservative way of life to the changes around them.

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Now, new research by U.S. and British scientists led by geologist William D’Andrea at Brown University, Providence, RI, reconstructs 5,600 years of climate history buried in lake sediments of West Greenland that links temperatures and three human migrations in the region, including the Norse. Their study was just published in the Proceedings of the National Academy of Sciences.

First came two Arctic peoples. The Saqqaq arrived about 4,500 years ago, at a time, the researchers say, when western Greenland was relatively warm. Caribou were plentiful and marine food sources were easily reached. About 1,700 years later, during an interval of severe cold, these warm-weather hunters were replaced by the Dorset people, who were better equipped for ice-hunting conditions. For reasons not explained by the climate record, the researchers say, the Dorset departed after 700 years and western Greenland remained uninhabited until the Norse arrived 1,000 years later.

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As it happened, in the 1990s, analysis of ice cores taken farther inland near the Greenland ice cap’s summit first confirmed the climate system’s natural ability to change abruptly — in a matter of decades, much quicker than scientists previously thought. But the record of lake sediments D’Andrea and colleagues collected recorded the temperatures experienced by the Norse Vikings when and where they lived.

“So we can say there is a definite cooling trend in the region right before the Norse disappear,” D’Andrea said in a release issued by Brown University. Observed co-author Yonsong Huang, also of Brown: “It is interesting to consider how rapid climate change may have impacted past societies, particularly in light of the rapid changes taking place today.”

IMAGE 1: View of southwestern Greenland taken from the Space Shuttle in 1992. CREDIT: NASA

IMAGE 2: Map shows area of study in red square and areas of ancient Norse settlements. CREDIT: Proceedings of the National Academy of Sciences