Ice shows how Charlemagne’s death chilled economy

Arctic­ ice shows how bickering­ among Charlemagne’s offspring sent the global economy into a tailspin in 814.

Europe's most powerful monarch Charlemagne.

An analysis of centuries-old Arctic­ ice has revealed how bickering­ among Charlemagne’s offspring sent the global economy into a tailspin in 814.

Long cores of ice extracted from 13 sites across Greenland and the Russian Arctic illustrate with new precision how the contin­ental economy withered as Charlemagne’s heirs squabbled over his empire, plunging Europe into some of the dimmest years of the Dark Ages.

The cores capture fluctuations in levels of atmospheric lead pollution­ over centuries. These, in turn, indicate how much silver was being smelted in Europe.

High pollution levels suggest that during Charlemagne’s rule silver production reached levels not achieved since the Pax Romana, the apogee of the Roman Empire. His death coincided with a slump, signalling plummeting produc­tivity at his mints.

“The link is striking,” said Joe McConnell of the Desert Research­ Institute in Nevada, co-author of a paper published yesterday in the Proceedings of the National Academy of Sciences. “You almost feel sorry for Charlemagne’s heirs — everything craters­ around them.”

Humans have been polluting the atmosphere with lead since 1000BC, when the Phoenicians began buying silver purified by the people of Spain, who mined and roasted lead-silver sulphide ores. The metal used in coins such as the Roman denarius was largely derived from lead-rich galena ores and lead was used to extract silver.

Only recently, however, have these contaminants been used to sketch history. Lead pollution can travel on the wind for thousands of kilometres, with tiny amounts settling on ice sheets in the Arctic.

As the sheets build up these particles form a frozen chronicle: a tale of famines, wars and plagues told by how much silver was being produced. The technique works well because natural lead levels in the environment are very low, making deposits in layers­ of Arctic ice a sensitive indicato­r of economic activity.

The new analysis looked at 13 Arctic ice cores, scattered over 4000km. The Thirty Years’ War of 1618-1648 is known to have disrupted mining and the central Euro­pean economy. It shows up quite clearly.

The ice also bears the mark of mining in Derbyshire, in particular the adoption of gunpowder for blasting in the late 17th century, and humanity’s susceptibility to pestilence stands out, with the second­-century Antonine Plague and third-century Plague of Cyp­rian damaging economic activity.

The effects of climate change are seen, with the Little Ice Age, beginning in about AD1300, coinciding with an economic dip. That was merely a prelude to the Black Death of the 14th century, in which a third of the European population is thought to have perished. Silver smelting did not recove­r for five or six generations.

Lead pollution increased as much as 300-fold from the early Middle Ages to the industrial peak of the 1970s. This reflected not only silver production, but fossil-fuel burning and other industri­al activities.

Co-author Andrew Wilson of Oxford University said: “These ice-core records are helping his­torians to understand and quantify the ways that societies and … economies … responded to external forces such as climate disruptions, plagues or political unrest.”

The Times