Thursday, July 22, 2021

"Holy Water: Miracle Accounts and Proxy Data Tell a Climate Story"

I realize that with that headline I come dangerously close to encroaching on the turf* of a certain Financial Times editor and can only hope I have not crossed the line.

From the American Geophysical Union's EOS:

In 6th century Italy, saints were said to perform an unusual number of water miracles. Paleoclimatological data from a stalagmite may reveal why.

In early medieval Italy (then a troubled peninsula transitioning from the collapse of Roman rule) a group of monks at a mountaintop monastery had a water problem. To fetch their supply, they needed to descend from the monastery’s steep and rocky perch. To their aid came St. Benedict, who spontaneously brought water to the summit in the form of a spring.

According to a new study, this account does more than relay the performance of a miracle. It also suggests that climate change played a previously unassociated role in societal shifts long recognized by historians.

The study, published in the journal Climatic Change, brought together an international group of geoscientists and historians led by researchers at the University of Warsaw and the University of Pisa. Authors examined both paleoclimatological proxy data and historical records to gain a fuller picture of the impact that a prolonged period of increased rainfall had on Italian society in the 6th century. Their findings indicate that contemporaneous water-related miracle stories go beyond the anecdotal to reveal one way local Christian leaders responded to a period of climate extremes.

A Stormy Century

After the collapse of the Western Roman Empire in the late 5th century, central and northern Italy came under siege by invading forces, and decades of war left the peninsula hobbled and depopulated. Into this maelstrom swept a century-long spell of bad weather, a circumstance that provided rich material for Pope Gregory I (Gregory the Great), whose Dialogues on the Miracles of the Italian Fathers, written in the 590s, included descriptions of holy figures bringing forth storms, conjuring new water sources, and rerouting troublesome rivers.

Hagiographical accounts are generally considered anecdotal or derivative. But when combined with proxy data, the Dialogues’ water-related stories, along with those of other 6th century writings, may demonstrate that the society affected by the century’s changing weather patterns also responded to attempts to explain or contextualize them.

“Even when climate is not causing the economic or social system to collapse, there might be some important influences, some impact on other levels of human functioning…on our thinking and our behavior,” said study coauthor Adam Izdebski, independent research group leader at the Max Planck Institute for the Science of Human History. It can be as simple, he said, as people noticing the weather and leaders taking advantage of that awareness. For Gregory, it was an opportunity to move the cultural tide in the church’s favor.


“Hagiographical sources show us the world as the people who produced them saw it,” said Samantha Kahn Herrick, an associate professor of history at Syracuse University who was not involved in the study. “They reveal how people made sense of what was happening. Even historical sources that seem much more banal and straightforward are always shaped by their authors’ sense of what’s possible and what’s important.”

A Layered Story

Researchers obtained climate data by analyzing a stalagmite collected from Renella cave, located near the town of Lucca in northern Tuscany. By measuring oxygen isotope ratios in the stalagmite’s layers, researchers were able to determine whether environmental conditions were wet or dry when the layers were formed. They then used uranium-thorium dating to pinpoint when those conditions occurred. The stalagmite provided nearly a thousand years of data from the period before 900 CE and showed that northern and central Italy experienced hydrological extremes during the 6th century.

The culprit, according to study authors, was likely a negative phase of the North Atlantic Oscillation (NAO), a winter weather pattern that brings moisture from the Atlantic Ocean to parts of Mediterranean Europe, in this case resulting in decades of increased precipitation during the colder months. Researchers analyzing the stalagmite from Renella found that in the 6th century, precipitation in the region was distinguished by a particular isotopic trace that’s left by moisture from the Atlantic....


*See for example: 

Izabella Kaminska On The Intangibles that go into Valuation With a Look at Contango in the Market for Water from the Grotto of Massabielle in the Sanctuary of Our Lady of Lourdes, France

And the somewhat related: 

I Hate The FT's Izabella Kaminska: Pontifex Edition