Ancient solar storm proves Vikings lived in Newfoundland by at least 1021 AD, scientists say

A group of researchers from the Netherlands claim they've added to a pool of evidence proving the Vikings were the first known Europeans to cross the Atlantic and set foot on North American soil, erecting a small settlement on the north coast of Newfoundland at least 1,000 years ago.

The discovery builds on previous estimates from Canadian researchers, who unearthed the remnants of a small Norse village near St. Anthony, N.L., in the 1960s.

That theory made it into textbooks decades ago, but it wasn't until this year that scientists could offer hard evidence to support a precise date when the Norse actually lived there, according to Michael Dee, a geoscientist at the University of Groningen.

The research, published this week in the scientific journal Nature, uses a radiocarbon-dating method so accurate, the team says they've pinpointed a single year in which the Vikings inhabited a grassy, windswept coastal area known today as L'Anse aux Meadows.

Using wood samples from that settlement, Dee was able to count the rings on each trunk, starting from a specific marker: a spike in carbon isotopes from an ancient solar storm that deposited a blast of cosmic radiation into the Earth's atmosphere in 993 AD.

Trees around the world absorbed that extra radiocarbon, harbouring it inside their trunks and providing scientists with an accurate way to measure time using wood samples.

"There were moments in time where there were these sudden upsurges in radiocarbon … that pass through, into the trees, as a sort of pulse," he said. "We used that pulse."

Once the team detected that solar marker in old archeological findings, it was a simple matter of counting the trees' rings, from the year of the storm to when the tree was felled in 1021 AD, Dee said.

The team also determined their samples were from trees chopped down with metal tools, which only the Vikings used, Dee explains — ruling out involvement by the ancestors of the Beothuk, the Indigenous people who lived in Newfoundland at the time.

The finding has now set the earliest known date that humans circumnavigated the globe, according to the paper, completing a journey that began thousands of years earlier when nomadic peoples crossed over the Bering Strait from Asia.

Radiocarbon dating isn't a new technology, Dee noted. But it's only in the last couple of years that scientists became aware of the solar storm, a rare cosmic event that spiked radiocarbon levels in trees around the world only twice in the last 2,000 years.

That finding immensely bolstered the power of chronological analysis, he said, allowing them to apply the new dating method to the mystery of early European exploration. But it's not clear how long the Vikings remained in Newfoundland, or whether 1021 was the year they arrived, Dee warned. 

Dee credited Canadian researchers, whose work on the subject dates back nearly 50 years, with providing the basis of their discovery.

Birgitta Wallace, a retired archeologist with Parks Canada, helped excavate L'Anse aux Meadows in the 1970s, finding simple wooden structures that she says match Norse architecture in Iceland.