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Climate change is a threat. Fanaticism is a bigger one

For years, economic historians looked at the wars of the 17th century through the lens of statehood, conquest and religious fervour. But there is a different story told by climatologists

This week the European Copernicus Climate Change Service revealed that the world just experienced the warmest January on record. The average temperature was 0.7 degrees higher than the 30 years up to 2020 and 1.66 degrees higher than typical January temperatures in the pre-industrial era. So, as I strolled across the Pont d’Avignon last Sunday morning nursing a post-Marseilles sore head, I was thinking of pre-industrial age climate change.

Avignon, the seat of the Vatican in exile for most of the 14th century, is a medieval architectural gem. The bridge is probably its most famous monument, remarkable because it only spans half the Rhone river. Built in the 13th century, it was allowed to fall into disrepair in the early 17th century and buckled under mass flooding later in the century. The Pont d’Avignon, France’s most famous bridge, was the victim of climate change.

In the early 17th century, Europe was afflicted by what became known as the mini Ice Age, when temperatures fell by around a degree, with devastating consequences. This extremely violent century saw civil war in France and Britain as well as devastation in Ireland, where more than 500,000 died. It is estimated that one Irish person in five died between 1640 and 1660 – and it wasn’t just because of Cromwell, although he did his bit.

Across Europe, the 17th century was a period of intense religious fervour, genocide and dramatic population disenfranchisement and movement. (If you are interested in the economic history of the period, read Geoffrey Parker’s Global Crisis: War, Climate Change & Catastrophe in the Seventeenth Century.) The French philosopher Voltaire, born at the end of the century, was the first we know to describe that convulsive time as a global crisis. Looking back from the vantage point of 1740s Paris, Voltaire noted that three things havea constant influence over the mind of man – climate, government and religion”.


For years economic historians looked at the wars of the 17th century through the traditional lens of statehood, conquest and religious fervour. However, there is a different story told by climatologists and demographers, who argue that from 1618, just when the population of western Europe was at its highest ever, the temperature began to drop precipitously, producing harvest failures, soaring food prices and devastating pandemics.

Taken together, across the northern hemisphere from China to Japan and France to Ireland it is now thought that the population fell by one-third. That’s what climate change can do.

Around the Papal city of Avignon, French Protestants, who had been allowed to live in relative peace for a few decades, became targets again as Protestants were blamed for crop failure, disease and famine

Reports from the 1610s onwards speak of torrential spring rains, snowfall in previously subtropical regions, rivers such as the Bosphorus freezing over. The year 1627 was the wettest recorded in Europe in 500 years, while the following year became known as “the year without a summer”. Lower temperatures meant crops failed to ripen. In Ireland, snow in October 1641 signalled what was the coldest winter on record leading to a “dearth of corn as not seen in Ireland in memory”. Of the 62 recorded floodings of the Seine in Paris, 18 occurred in the 17th century, while in England 10 harvest failures occurred in the 16 years to 1661. Poland experienced frost on 109 days in 1666 as opposed to 63 days on average.

The 1640s, a calamitous decade in Ireland, saw temperatures fall by as much as 2 degrees in the growing season, reducing agricultural yields by between 30 and 50 per cent, sending food prices upwards. This affected the economy in three specific ways. First, most people spent most of their money on food so that incomes were immediately slashed. Second, spending on food reduced spending on anything else, knocking on negatively to artisans.

Third, food prices don’t rise in a straight line, they spike upwards. Suppose a farmer harvested 500 bushels of grain. Of this he needed 175 to feed his animals and 75 for his family, leaving 250 for the market. Imagine bad harvest cuts production by 30 per cent to 350 bushels. The farmer still needs 250 for his own use, leaving only 100 bushels for the market, a fall of 60 per cent. Poor people begin to starve.

A couple of years of this and we are facing catastrophe. Hungry people are more prone to catching disease, such as diarrhoea and dysentery, both efficient killers of the weak. Without sufficient calories – about 1,500 a day – we weaken and die quite quickly. Lack of calories also diminishes our ability to work and thus earn. A vicious cycle establishes itself, triggered by a small adjustment in temperature.

With such devastation, the search for scapegoats kicked off in earnest. Calamity was linked to bad behaviour and people were instructed to refrain from dancing, drinking, fornicating, adultery and gambling. Censorious religious morality flourished. In England, Christmas and maypoles were banned. By the mid-16th century, witch-hunts were common across parts of Europe. Poor people, mainly poor women, were accused of having brought on disaster through witchcraft and thousands were drowned or burnt at the stake. Hungry people denounced neighbours. Protestants and Catholics blamed each other and many blamed Jews.

As fear and confusion reigned, tribal factions turned from distrust to all-out war. In the 60 years to 1680, Poland was only at peace for 27 years, Holland for only 14, France for just 11 and Spain for a mere three years. During the 1640s, the years of revolt in Ireland, no European state avoided war.

In the freezing winter of 1641, a fear of Irish papists gripped England and one third of all pamphlets published in London in 1642 were about the Irish threat. The Catholic Confederacy, based in Kilkenny, was winning the sectarian war on the island. By 1647, when only Dublin and Derry remained in Protestant hands, Cromwell turned his New Model Army towards Ireland.

While Irish Catholics were targeted by England, French Huguenots were targeted in France. Around the Papal city of Avignon, Protestants, who had been allowed to live in relative peace for a few decades, became targets again as they were blamed for crop failure, disease and famine. By 1661, a full-scale internal war was being prosecuted against Huguenots by King Louis XIV, mirroring Cromwell’s fanatical anti-Catholicism in Ireland.

Irish Catholics and French Huguenots were mirror images of each other. The word refugee comes from the original French word referring to the fleeing Huguenots, about 5,000 of whom came to Ireland, freed from terror in France but inadvertently benefiting from terror in Ireland.

Back in Avignon, the partly wooden bridge was weakened by the unusual frosts as the mini Ice Age set in. In the last years of the century, as temperatures began to rise again, the resulting floods on the Rhone washed away part of the remaining arches, leaving the famous amputee bridge I walked upon last Sunday.

The next time someone tells you that climate change doesn’t matter, point them to Europe in the mid-17th century. In many European countries, rural populations fell by more than one-third. Climate alone didn’t cause the problem, but the fanaticism pursued by political and religious leaders turned a climate change and a sudden drop in temperature from a crisis into a catastrophe. Food for thought.