A Cataclysmic Event May Have Driven Iceland's Conversion To Christianity


Robin Andrews

Science & Policy Writer

The land of ice and fire. Nathan Mortimer/Shutterstock

Once upon a time, over a thousand years ago, an Icelandic eruption changed not just the real world, but the supernatural one too. As stunningly recounted in a brand-new paper, this volcanic violence – the largest event in Iceland’s settled history – not only triggered upsets around the planet, but it also may have aided the proliferation of Christianity on the land of ice and fire itself.

Writing in the journal Climatic Change, a multidisciplinary team of glaciologists, dendrochronologists, historians, and volcanologists – led by Cambridge University – describe their success in finally placing firm dates on the elusive Eldgjá eruption.


The event was known to have been profuse, producing enough lava to cover the entirety of England by several inches. Although known to take place shortly after the Vikings and Celts settled on Iceland in the late 9th century, many of the details of this appropriately named “lava flood” have remained fuzzy over time.

Using ice cores in Greenland containing trapped volcanic particles, along with tree ring data, the team placed the eruption’s timeline as beginning in the spring of the year 939 CE, and continuing until autumn 940 CE. Their geochemical analysis also revealed that a voluminous plume of sunlight-reflecting sulfur aerosols spread across much of the Northern Hemisphere.

From Central Europe and Scandinavia to the Canadian Rockies and Central Asia, summer temperatures in 940 were around 2°C (3.6°F) lower than usual. As the authors note in their paper, this coincided with famines and the spread of a cattle-borne plague in France, Switzerland, and Sicily, as well as harvest failures in China. Settlers on Iceland were likely put in a similar spot of bother.

This is nowhere near the first volcanic eruption to affect the climate. Some can bring about biological apocalypses; others can simply exacerbate the collapse of a superpower, such as Pharaonic Egypt. This particular Icelandic eruption's effects brings to mind the Tambora blast of 1815, whose millions of tonnes of sulfur aerosols robbed the world of 1816’s summer, helped drive the Opium War, and influenced a major cholera outbreak.


Tambora's climatic terrors also probably helped accidentally lead to the birth of Mary Shelley’s Frankenstein. Conversely, it appears that Eldgjá's frightening fireworks contributed to the death of the Old Norse gods in favor of the man that walked on water.

As the team posits, the famed Icelandic ~961 CE poem Vǫluspá (“the prophecy of the seeress”) may have been partly inspired by Eldgjá’s anger, as it speaks of a monstrous wolf that swallows the Sun.

“The sun starts to turn black, land sinks into sea; the bright stars scatter from the sky,” it reads at one point. “Steam spurts up with what nourishes life, flame flies high against heaven itself.” Another line, “venom-drops flowed in through the roof-holes”, may recall acid rain associated with volcanic plumes, according to the study.

The researchers suggest that not only does this certainly sound like the contemporaneous Eldgjá event, but they point out that the apocalyptic poem is used as an “allusion to the fiery terminus of the pagan gods” and the emergence of just one omnipotent deity. Christianity was formalized at the turn of the subsequent millennium by the Icelandic parliament, and it's thought that the recounting of the evocative, allegorical Eldgjá eruption played a catalyzing role in this otherwise gradual nationwide proselytization.


Lead author Clive Oppenheimer, a professor of volcanology at Cambridge University, told IFLScience that massive volcanic eruptions in Iceland have tended to make marks on the cultural memory of Icelanders. The ferocious 1783-4 Laki eruption, for example, was interpreted by a renowned pastor at the time “as God's retribution for the wicked ways of his people.”

“Events of this nature and scale are not only rare in Iceland but rare globally,” Oppenheimer added. “These are events that go down in history.”

The link between Eldgjá and Vǫluspá is admittedly circumstantial, but it’s strong – and not that unusual.

Eruptions are rarely anything but incandescent, awe-inspiring, bone-rattling events. They’ve appeared in tomes, paintings, and legends throughout time, from the 37,000-year-old wall paintings in France’s “cave of forgotten dreams” to the 7,000-year-old oral history of a genuine hellish cataclysm in Aboriginal Australia.


Are we really surprised Thor et al. are no match for a volcano's fury?


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