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We have experienced climate change before — and it was terrible

Today it’s expected to reach 40 degrees centigrade in London, beating the previous record for the hottest day in Britain by a degree or two. I would say that it’s something to tell your grandchildren about, but of course your grandchildren will regularly experience this temperature, and far worse. 

The climate is changing, with all that entails, something we’ve known about for several decades now. Among the early proponents of the theory of climate change was mid-century climatologist Hubert Lamb, who spent most of his career at the Met Office and during the course of his studies made a curious historical discovery.

It was once widely believed that climate remained relatively stable over recorded history, civilisational lifespans being too brief to see such grand changes. But while looking into medieval chroniclers, Lamb was struck by the numerous references to vineyards in England, some as far as the midlands. As long as anyone had ever remembered, the country had been too cold to grow wine, except in tiny pockets of Sussex which occasionally produced almost-drinkable white. 

William of Malmesbury, living in the 12th century, observed of his native Wiltshire that ‘in this region the vines are thicker, the grapes more plentiful and their flavour more delightful than in any other part of England. Those who drink this wine do not have to contort their lips because of the sharp and unpleasant taste, indeed it is little inferior to French wine in sweetness.’ How could that have been?

Lamb concluded that Europe must have been considerably warmer during the Middle Ages, and in 1965 produced his great study outlining the theory of the Medieval Warm Period; this posited that Europe was at its hottest in the High Middle Ages (1000-1300) and then became unusually cool between 1500 and 1700. 

Since then, Lamb’s thesis has been reinforced by analysis of pollen in peat bogs, as well as the radioactive isotope Carbon-14 found in tree rings (the less sun, the more Carbon-14). In Medieval Europe, every summer was a hot girl summer — and tiny changes could make earth-shattering differences.

Such is the delicacy of the global ecosystem, William Rosen wrote in The Third Horseman, that even ‘a tiny blip in oceanic temperature can alter atmospheric temperatures for a thousand years’. In the ninth century ‘a few of those oceanic conveyor belts fell into a state of equilibrium for a moment infinitesimally short in geologic time, but a significant fraction of a human history’.

Just as climate change helped to bring down Rome, so the civilisation that followed was at the mercy of much greater forces — but fortune favoured them and from 900 AD the continent began warming up. The increase in temperature led to ten or even 20 days extra growing season and that meant far more food; during the medieval warm period England’s population went from 1.5 to 5 million, and France’s from under 6 to between 17 and 21 million. (Indeed France, generally, had a massive pre-modern population). In Europe as a whole, the number of people may have increased four-fold, although climate was not everything, the invention of the horse-collar being a huge breakthrough in food production (agricultural innovation is probably the least sexy area of history, but this was very important). And during the height of this long summer, vineyards were found across the south of England.

And yet increasing numbers of people were falling into what later became known as the Malthusian trap. Surviving skeletons show that the average height in England fell from about 174cm (5’8.5”) in the year 1000 to 168cm (5’6”) by the start of the 14th century. This left the malnourished population very exposed in case of any change in climate — and that change would come.

An ominous sign of the approaching catastrophe came in January 1308, when England’s King Edward II arrived in Boulogne-sur-Mer for his wedding to Isabella, daughter of the king of France — for what turned out to be the most disastrous of marriages. The weather was unusually cold, 30-40°F below the average for the year, delaying the Channel crossing and seeing the marriage service conducted in below-freezing temperatures.

Across Europe, people must have noticed a change. Farmers in the Saastal Valley in Switzerland were probably the first to observe what was happening, back in the 1250s, when the Allalin Glacier began to flow down the mountain. Surviving plant material from Iceland suggests an abrupt decrease in the temperature from 1275 — and, as Rosen points out, a reduction of one degree made a harvest failure seven times more likely. From 1308 England saw four cold winters in succession; the Thames froze, chroniclers recalling dogs chasing rabbits across the icy surface for the first time.

As with many things, change was gradual, until it was dramatic, for then came the disastrous year of 1315. The Chronicle of Guillaume de Nangis, written by a monk at the Abbey of Saint-Denis outside Paris, recorded that in April the rains came down hard — and didn’t stop until August. 

Drenched and starved of sunlight, the crops failed across Europe. The price of food doubled and then quadrupled. By May 1316, crop production in England was down by up to 85 percent and there was ‘most savage, atrocious death’, as a chronicler put it. Hopeless townsfolk walked into the countryside, searching for any bits of food; men wandered across the country to work, only to return and find their wives and children dead from starvation. At one point, on the road near St Albans, no food could be found even for the king. Emaciated bodies could be seen floating face down in flooded fields.

The Great Famine killed anywhere between 5-12% of the European population, although some areas, such as Flanders, suffered far worse death rates, losing up to a quarter of their population to hunger.

An Irish chronicle wrote that people ‘were so destroyed by hunger that they extracted bodies of the dead from cemeteries and dug out the flesh from the skulls and ate it’. Across Europe the bodies of hanged criminals were pulled down and eaten. In Poland, Estonia and Silesia there were reports whereby ‘parents devoured their children and children their parents’. The sinister fairy tale Hansel and Gretel may originate with the Great Famine, when sending children off to the forest was preferable for desperate parents to watching them starve.

Crime shot up, and landless knights and men-at-arms took to extortion, while mobs from the countryside flooded into Paris and seized the Grand Châtelet, the city’s main stronghold, pillaging abbeys and attacking Jews. In England, where Edward II battled with his leading barons and then his estranged wife, the country was overrun with gangs of outlaws, and some historians link the Robin Hood myth with this period (the original ballads refer to ‘King Edward’).

As well as food, the production of wine was also devastated, grapes requiring one hundred days of sun a year. In 1316 it was recalled that ‘there was no wine in the whole kingdom of France,’ much to their obvious distress. The furthest extent of wine production now receded south, towards its modern-day limit of Champagne and Saxony. Cultivation in England continued for some time, but the produce was of far inferior quality, until by the Victorian age a popular magazine joked that drinking English wine required four people — one to drink it, two to hold him down, and the other to force it down the victim’s throat.

The winter of 1317-8 was the harshest of all, with cold weather lasting almost until May. Much of the Baltic Sea froze, and the rivers feeding it turned to ice, isolating many coastal cities. The brief climatic equilibrium was over, and during the next two centuries the continent would get far colder, often with horrific results. Historically the cold has been Europe’s biggest fear, a time of hunger, and the early modern period was certainly one of great anxiety, fanaticism and cruelty. As well as decades of religious warfare, there may be a link between cold weather and witch hunts, as well as anti-Jewish pogroms. This Little Ice Age was captured by Pieter Bruegel the Elder’s Hunters in the Snow, showing the men returning home with meagre offerings.

None of this is to minimise concerns about global warming; although like a lot of people I find the scolding and hypocrisy over ‘the climate crisis’ deeply irritating, I’m inclined to believe that it is indeed something to seriously worry about, although perhaps not quite as apocalyptic as some would believe. My instincts are conservative, and I think radical change is bad in itself, that protecting the environment is among the most important of duties, that we should expect our government to ensure clean rivers and oceans, and healthy biodiversity is an absolute priority. Forty-degree heat in Britain is not to be laughed off, because the gradual can and often has turned catastrophic.

The good news is that drinking English wine won’t require anyone to hold you down any more, with vineyards expected to be found scattered across the south and midlands. Apparently the area just north of London has among the best soils in Europe and, if things get a couple of degrees warmer, Luton may rival the banks of the Gironde as the most desirable wine country on earth. So, there is some bright side to it all.