The Great Warming

by Brian Fagan

  Salt herring was cheap and ubiquitous, but an unattractive food, spurned if possible even by the poor, for it tasted like wood unless cooked with elaborate spices. Yet the demand was insatiable. The glory days of the herring fisheries were in the early fourteenth century, during the closing decades of the warm period. It may be no coincidence that the herring schools and fish landings at places like Yarmouth suffered a major decline as conditions grew colder after 1300 and sea surface temperatures in the North Sea declined. A combination of overfishing in response to insatiable demand, better salting methods, and, perhaps, climate change tipped the medieval herring industry from sustainable to unsustainable.

  The Norse introduced a much more palatable alternative in their warships and merchant vessels: dried and salted cod, often called stockfish.18 Gadus morhua, the Atlantic cod, is a white fish with firm flesh that has a low fat content. Every winter, fisherfolk in the Lofoten Islands of northern Norway would catch and dry cod, which the Norse used as staple tack on their voyages. Tightly packed stacks of cod fed their crews during the great voyages of the Medieval Warm Period. During the same centuries, the Hanseatic League of the Baltic, which already had a stranglehold on much of northern Europe’s grain trade and the yields of its then abundant harvests, discovered that it could generate enormous profits by trading grain from more temperate climates for cod loaded at Bergen in southern Norway. The Hanse already dominated herring commerce. They now added cod to the inventory, so English fishers started sailing far offshore, to cod fisheries off southern Iceland, where they could outflank the Hanse. At the same time, they found a substitute for fluctuating herring stocks at a time of cooling temperatures. Their fishing boats, their technology, and their experience came from centuries of fishing in North Sea waters during the benevolent summers and mild falls of the warm centuries. This apprenticeship served them well as cod fleets moved to Ireland and Iceland, and, ultimately, to the Newfoundland fisheries of later centuries.

  IN EUROPE, THE WARM centuries had their profoundest direct effect on common folk, the anonymous people who fed society. Kings, princes, and lords enjoyed estates and landholdings, and they engaged in intrigue, war, and sometimes crusades. Theirs was a life of elaborate ceremonies, of chivalry, cruelty, and violence. Their expertise had little relevance to the knowledge required to work the land, to cope with the vagaries of sudden climatic shifts. Most commoners worked the land; a large percentage were free laborers, many with specialized expertise. Many grew cereal crops; these people were knowledgeable about crop rotation, plant diseases, and storage. There were cowherds, shepherds, and swineherds, others who were adept at drainage. Eel catchers thrived by rivers and lakes and in remote marshes, for the easily smoked eel had become a standard currency for rent. Women raised bees, brewed ale, and spun wool. Each generation learned from its predecessor in apprenticeships and by word of mouth, passing on an enormous body of often arcane information that came with working the land in all weathers in a climate where shifts between warm and cold, wet and dry, could arrive almost overnight.

  To lords and princes, the peasantry was an anonymous presence that cultivated the soil and provided food. But it was these humble folk who kept Europe fed and who adjusted their farming to warmer times. Their food surpluses fed the armies and the laborers building not only palaces but also those most impressive of all medieval structures, the Gothic cathedrals. Their labors felled the trees for the beams, quarried the stone for the towers and soaring naves. The great churches, visible for miles around, linked the living and divine worlds, for, in those pious days, all things emanated from the Kingdom of God. Great cathedrals like Sens and Chartres, built at enormous expense, were metaphorical sacrifices of stone and material goods offered in expectation of divine favor. The favor most people sought was a good harvest, for even in these warmer times, the farmer could never relax.

  FOUR HUNDRED YEARS of rapid population growth and generally plentiful food supplies, of unbridled forest clearance and fast-growing towns and cities: Europe was a very different continent at the end of the warm centuries. By the late thirteenth century, however, Europe was facing serious economic problems, for population growth had outstripped the equivalent jumps in agricultural production.19 By 1300, much of the population was worse off than it had been a century earlier, as inflation undermined wealth and the upper classes placed ever greater demands on commoners. The farmers responded by taking up marginal lands and by other shortcuts such as shortening fallow periods, which, in a time of relatively predictable summers, may have seemed logical ways of boosting crop yields. Inevitably, farmers’ indebtedness to landowners increased, while economic uncertainty also struck home in cities, where the vagaries of the wool trade and other industries could wreak havoc, and military blockades were a fact of life.

  All of these problems had the potential to turn much of western Europe into a powder keg, but climatic events intervened dramatically in 1315. “During this season [spring 1315] it rained most marvellously and for so long,” wrote a chronicler of the day, Jean Desnouelles.20 The rain began seven weeks after Easter, just as the new crops were in the ground. Soon, freshly plowed fields were quagmires, the seeds washed out of the ground. Muddy soil cascaded down the freshly cleared slopes of marginal lands, creating deep gullies in new fields. Corn and oat crops, heavy with moisture, barely grew ripe. The deluge continued into autumn. There was hunger by Christmas as a “dearness of wheat” began. Even military campaigning, which normally continued in any weather, stopped in its tracks. When fighting resumed, it prevented the distribution of grain to hungry communities. The rains continued in 1316, reducing many to penury as crops simply did not ripen. “There was a great failure of wine in the whole kingdom of France” as mildew attacked the grapes. The suffering continued for seven years, ending with a bone-chilling winter in 1322 that immobilized shipping over a wide area.

  Grain production over much of northern Europe during these years may have fallen by as much as a third, although, of course, the effects differed from place to place. Herds and flocks were reduced by as much as 90 percent owing to diseases such as rinderpest and liver fluke brought on by wet weather. Fruit rotted on saturated trees; coastal fisheries and fish ponds were devastated, all this apart from the damage to industrial crops such as flax. At least 30 million people were at risk of malnutrition. No one knows exactly how many Europeans perished from hunger and famine-related diseases, but there were at least 1.5 million deaths, most of them the poor. Inevitably, in a pious and superstitious age, the famine was attributed to the wrath of God. Processions of flagellant penitents wound through the streets of cities and towns.

  By the time the hunger years ended, the more settled climate of the warm centuries was a distant memory. Much more unpredictable conditions, greater storminess, and cycles of very cold winters or warm summers marked the gradual beginnings of the Little Ice Age. But worse was to come a little more than a generation later. In 1347, a ship from the Black Sea appears to have brought the plague to Italy. The plague bacterium, Yersinia pestis, lives in fleas, which live on warm-blooded hosts such as rats, humans, or cats. The Black Death, so named after the dark discolorations of the skin resulting from infection of the blood, spread rapidly along trade routes into France.21 By 1348, it had struck England and Spain, then Scandinavia. Between 1348 and 1485, thirty-one major outbreaks descended on England alone. Eighty million people lived in Europe in 1346. Twenty-five million of them perished in the pandemic of 1347–51. From a low in 1450, England’s population did not reach preplague levels again until about 1600, Norway’s not until 1750.

  There was no defense against the Black Death, which spread like wildfire among crowded urban populations. No herbal remedies worked; leeches and bloodletting provided no relief. Because no one knew how the disease was spread, nobody took measures to eliminate the rats and other animals that carried the infected fleas. Once it became clear that the risk of infection was lower away from crowded cities, the nobility and middle classes moved int
o the countryside. Some religious communities where monks lived in close quarters lost as many as 60 percent of their members. The church was plunged into crisis; agricultural production plummeted; landowners had difficulty finding peasants to work their land. Agricultural wages rose rapidly, but those subsistence farmers who survived may have been somewhat better off, as there was more land to go around and fewer mouths to feed, both in the countryside and in the cities. Marginal lands everywhere now reverted to fallow. But new waves of infection in the 1360s soon wiped out any gains, quite apart from the emotional impacts of the loss of a third (the proportion is controversial) of Europe’s population in a few years. Only the constant wars continued, waged by rulers in the belief that the Lord had brought famine and plague on the people as punishment for their sins. Those who fought one another or practiced economic oppression believed they were doing God’s bidding with virtuous acts that would restore justice to the world. Rural and urban violence rose to unprecedented heights in a Europe that, after the Black Death and the warm centuries, was never the same.

  But the Medieval Warm Period had helped change Europe beyond recognition, and had widened the mental and physical boundaries of European society. During these centuries, Norse voyagers took advantage of favorable ice conditions in the North Atlantic to sail westward to Iceland, Greenland, and Labrador—lands previously outside European consciousness. These voyages will be described in chapter 6.

  CHAPTER 3

  The Flail of God

  Now when he reached the Khan’s camp, at the end of the third month the grass was green and trees everywhere in bloom, and the sheep and horses were well grown. But when with the Khan’s permission he left, at the end of the fourth month, there was no longer a blade of grass or any vegetation.

  —Ch’ang Ch’un, The Travels of an Alchemist (1228)1

  “EUROPE IS SAID TO BE A THIRD OF the whole world,” a fourteenth-century encyclopedist informs us. “Europe begins on the river Tanay [Don] and stretches along the Northern Ocean to the end of Spain. The east and south part rises from the sea called Pontus [the Black Sea] and is all joined to the Great Sea [the Mediterranean] and ends at the islands of Cadiz [Gibraltar].”2 To medieval Europeans, the easterly reaches of the European plain were a virtually unknown realm, where gently rolling terrain receded into the far distance and eventually Europe became Asia. The population was sparse and, for the most part, constantly on the move, their movements dictated to a great extent by drought cycles.

  Deserts and semiarid environments are extremely sensitive to even tiny variations in rainfall. An inch (25 millimeters) more rain can shrink the frontiers of a desert by hundreds of square miles. Standing water may appear where none has been present for generations. Now suppose the rains continue to be slightly higher for a few years. Pastureland appears like magic; herds of antelope feed across what was recently arid terrain. Nomads graze their sheep and cattle near water holes and wherever graze can be found. Then the rains falter. Streambeds dry up; water holes vanish; the grass withers and dies. With the experience of generations, the herders move their beasts to the margins of the desert, to better-watered lands. Arid lands like steppes and deserts act like huge pumps. When rainfall increases even slightly, the breathing desert sucks in animals, plants, and people with its promises of grazing land and water. Like a giant lung, the pump may hold its breath for a while, but, inevitably, it exhales as dry conditions return, expelling nomads, their herds, and the antelope to its margins.

  Europe was well watered during the Medieval Warm Period, with slightly higher temperatures and with conditions somewhat drier but certainly favorable for subsistence agriculture. The Europeans lived on a geographical peninsula hedged in by much more arid environments, where the desert pump set the pace for much of human existence. Drought was the harsh reality of a warmer world in these environments, with the potential to change history.

  The Greeks and Romans thought of the nomadic tribes of Eurasia as the barbarians who lurked outside the gates, threatening destruction, rape, and pillage. One cannot entirely blame them: the Scythian nomads north of the Black Sea were known to drink from the skulls of their victims. In the same way, medieval Europe thought of itself as surrounded by a hostile world—pressed by Islam in the east, hedged in to the west by an ocean that extended to a stormy horizon, and threatened from Eurasia by nomadic tribesmen from the endless plains. The nomad threats were real. On April 9, 1241, an army of Mongols under a general named Subutai defeated the Polish princes under Henry the Bearded at Legnica in Silesia, now part of Poland. Henry’s heavily armored knights were no match for the nimble, arrow-shooting Mongols. The conquerors are said to have collected nine sackfuls of right ears from the bodies of the slain. Only the death of the Great Khan Ögötai Khan back in his homeland later the same year stopped the Mongol leader Batu Khan from pushing westward all the way to the Atlantic coast.

  The Eurasian steppe is an unforgiving environment, subject to drought and torrential rainfall, savaged by extreme heat and unforgiving cold. It was the home of one of history’s great conquerors: Ginghis (Genghis) Khan, whose empire expanded rapidly during the Medieval Warm Period.3

  GINGHIS KHAN CALLED himself “the Flail of God.” A brutal warrior, he descended on the settled lands of China and central Asia with bloodthirsty, hammerlike force. In 1220, he addressed the terrified citizens of Bokhara from the pulpit of the city’s central mosque: “Oh People, know that you have committed great sins, and that the great ones among you have committed these sins. If you ask me what proof I have for these words, I say it is because I am the punishment of God.”4 He spoke with a shrewd knowledge of the conquered.

  Like droughts and plagues, Ginghis Khan seemed an instrument of divine vengeance. Christian and Muslim alike cowered at his coming. The anonymous compilers of the Chronicle of Novgorod, a major staging point on the trade routes that linked Byzantium with the Baltic, called the Mongols “pagan and godless.” They were ruthless in victory. “God let the pagans on us for our sins,” lamented the chroniclers in 1238. “The devil rejoices at the wicked murder and bloodshed.” God was punishing the city with “death of famine, or with infliction of pagans, or with drought, or with heavy rain, or with other punishment. . . . But we always turn to evil, like swine ever wallowing in the filth of our sins.”5

  Ginghis Khan played the role of a conqueror with consummate skill. He was “a man of tall stature, of vigorous build, robust in body, the hair on his face scanty and turned white, with cat’s eyes, possessed of great energy, discernment, genius, and understanding, awe-inspiring, a butcher, just, resolute, an overthrower of enemies, intrepid, sanguinary and cruel.”6 While he preferred that his enemies surrender and submit, he resorted to slaughter if they defied him. When the rich Chinese city of Chung-tu, near modern-day Beijing, refused to submit, Ginghis Khan attacked in force, placing prisoners as attack troops in the frontline, then hurling the heads of the slain into the enemy’s lines. A few years later, a Muslim visitor noticed a white hill near the rebuilt city: it was constituted of the weathered bones of the thousands massacred when Chung-tu fell and was burned to the ground. The greatest of all Mongolian conquerors shed rivers of blood wherever his armies campaigned.

  Ginghis Khan was of humble origins, rising to prominence through sheer ability and ruthlessness. At first he was one of many leaders among a patchwork of nomadic tribes comprising some two million people and scattered across the vast Eurasian steppes. War was a way of life for the nomads, who fought on horseback. They were seasoned raiders and ruthless fighters, also fiercely independent, led by tribal chiefs who entered into alliances with others only with the objective of amassing wealth in livestock. In 1206, Ginghis Khan was elected Great Khan of the Mongols. He was a brilliant strategist and conqueror, but just as talented an administrator. He quickly broke up the ancient tribal structure, organized his army into tightly controlled standard units in multiples of ten, starting with the harban (ten men) and ending with the tümen (ten thousand soldiers).
The troops fought as units; no order had to be given to more than ten people at one time. Mongol armies were famous for their ability to fire their arrows in all directions while at full gallop. Each cavalryman wore a silk shirt under mail or a thick leather garment, which protected him effectively against arrows. They wore leather or metal helmets, and they carried two composite bows made up of pieces of wood and yak horn, and at least sixty arrows. Some carried heavy lances, clubs, and scimitars; others, swords and javelins. Every fighting man carried his own provisions, cooking utensils, and other equipment in an inflatable saddlebag made from a cow’s stomach. Mongol armies conquered by mobility, stratagem, and decoy tactics, and by using firecrackers made with gunpowder to terrorize a waiting army. They knew they terrified their enemies and made the most of it.

  At first, Ginghis Khan’s kingdom was little more than a patchwork of chiefdoms held together by the force of his personality, his military abilities, and the prospect of booty beyond imagination acquired by conquests and raids in settled lands. But, over a mere twenty years, Ginghis’s armies swept across the steppes and southward with breathtaking rapidity and ruthless efficiency. The Mongols slaughtered so many human beings that the Mongolian historian Juvaini remarked that the deficiencies would never be made good on the Day of Judgment.7 Famous cities were leveled to rubble; Iraq’s irrigation system, developed over many centuries, was smashed beyond repair. Thousands of Baghdad’s inhabitants were slaughtered without mercy in 1258. The ripple effects of the conquests spread far and wide. Christianity was weakened. Islam was much strengthened, but the faith that emerged from the ordeal of the conquests was narrower, more restricted, and closed to new ideas. The great traditions of Islamic learning in medicine, mathematics, history, geography, and astronomy that had flourished from 800 to 1200 now withered in the face of religious orthodoxy. Gradually, intellectual and scientific primacy passed from the Islamic world to western Europe. Meanwhile, the peaceful conditions in central Asia encouraged a few European travelers to venture along the intricate tracery of the ancient Silk Road to China, among them the Venetian Marco Polo (1254–1324), who entered the service of the Mongol emperor Kubilai Khan. By 1260, a Franciscan friar was archbishop of Beijing.