The Little Ice Age: How Climate Made History 1300-1850 Read online

  The Norse soon explored the fjords and islands of the west coast. The shoreline was relatively ice-free most summers, thanks to the north flowing West Greenland current, which hugs the west coast and flows into Baffin Bay. The favorable current carried the colonists' ships into the heart of a land of islands and fjords around Disko Bay they called Nororseta, which teemed with cod, seals and walrus. Nororseta became an important hunting ground, where the colonists obtained food for the following winter and precious trade goods, especially narwhal and walrus tusks, which were much prized. For many years, the Greenland churches' tithes to the diocesan authorities in Norway were partly paid in walrus ivory.

  Greenlanders sailing to Nororseta must have quickly become aware of lands to the west, if only because the prevailing currents in the northern hunting grounds carried them that way. The Davis Strait is little more than 325 kilometers across at its narrowest point. Even a modest journey offshore in good visibility would bring the high mountains of Baffinland into sight. The Norse found North America through a combination of accident and inevitability, having sighted the Arctic islands and mainland long before they set foot on western shores. They arrived in Nororseta at a time when summer ice conditions were usually less severe than in later centuries, which made it easier for them to take advantage of currents along the American side of the Strait.

  The West Greenland current flows into Baffin Bay and the heart of Nororseta, where it gives way to much colder south-flowing currents. Much cooler water passes southward along Baffin Island, Labrador, and eastern Newfoundland. This circulation pattern affects ice formation. The Baffin/Labrador coast has heavier ice cover and a longer sea ice season, whereas Greenland coast sea ice forms late and disperses early. There is often a coastal belt of ice-free water all the way up to the Arctic Circle on the eastern side of the Davis Strait. The climate of the Medieval Warm Period may have permitted easier navigation between Baffinland and Labrador during many summers.

  Yet the first documented sighting did not come from such a northern coasting voyage. Bjarni Herjolfsson, a young merchant shipowner and "man of much promise" who dreamed of exploring foreign lands, arrived in Iceland from Norway in about 985 and was shocked to find that his father had emigrated to Greenland with Eirik the Red a short time before. Refusing to unload his ship, he set off for Greenland at once, taking advantage of a fair wind. The wind dropped. For days Bjarni and his men sailed in northerly winds and fog with no idea of their position. Eventually they sighted a flat, well-forested coastline quite unlike their destination, "for there are said to be huge glaciers in Greenland." Bjarni stayed offshore and coasted southward, sighting more land at intervals. Eventually a southwesterly gale carried them offshore for four days. They made land at dusk at a promontory that had a boat hauled up on it, and so finally reached their original destination.

  The cautious Herjolfsson was criticized heartily for not setting foot on the mysterious coastline. Lief Eirikson, the son of Eirik the Red, bought Bjarni's ship, recruited a crew of thirty-five men, and sailed westward to Baffinland. Eirik himself reluctantly stayed behind after injuring himself on his way to the boat. Lief anchored off a rocky, glacier-bound coast, then cruised southward to a flat, well-wooded shore with sandy beaches, which he named Markland ("Forest Land") "for its advantages." He had reached part of modern-day Labrador, south of the northern limit of forests, somewhere near Hamilton Inlet. A favorable northeast wind carried them even further south, to the mouth of the Saint Lawrence River and to a region they called Vinland ("Wine Land"), perhaps after its wild grapes.

  The famous L'Anse aux Meadows archaeological site, in extreme northern Newfoundland, may be where Lief Eirikson and his crew wintered over and founded a transhipment station, where timber and furs were processed before being carried on to Greenland. Archaeologists Helge Ingstad and Anne Stine unearthed eight sod-walled structures on a terrace overlooking a shallow bay. The settlement had a work shed, a smithy, also storage structures and four turf boat sheds. The Norse knew how to choose a winter settlement. LAnse aux Meadows lies at a strategic point on the Strait of Belle Isle, at the mouth of the Saint Lawrence River, surrounded by water on three sides, with ample summer grazing for cattle. From :Anse and perhaps other camps, the Norse ranged widely, but how far south they sailed along the mainland coast remains a matter of controversy.

  All the information about Markland and Vinland was held by Greenland settler families with close-knit kin ties. They kept their information and sailing directions to themselves, just as fifteenth- and sixteenth-century Atlantic explorers did. Later expeditions encountered numerous indigenous people, who fought them so fiercely that the Norse never settled permanently in the western lands. But they visited regularly in search of timber, which was scarce in the Greenland settlements and easier to obtain from the west than from distant Norway. For two or more centuries, Greenland ships took passage to North America by sailing north and west and letting southerly ocean currents carry them to their destination. Then they sailed directly home on the prevailing southwesterly winds.

  These voyages were wracked by human and natural dangers: hostile indigenous people, polar bears, icebergs, sudden storms far offshore where rogue waves might swamp a laboring ship before the steersman could bear off before the menacing sea. But the greatest danger was suddenly massing sea ice, which could crush a stout Norse merchant ship in minutes. Even in summer, crewmen kept axes handy, ready to chip mantles of ice off the rigging before the boat became top heavy. The prudent navigator kept well clear of the ice margins, using word of mouth and years of experience to navigate Greenland waters. We know some of these verbal sailing directions from Konungsskuggsjd (The King's Mirror), a compendium of information about Greenland and adjacent lands written in the form of a sage's advice to his son in 1260. The anonymous author writes: "There is more ice to the northeast and north of ... [Greenland] than to the south, southwest, and west; consequently, whoever wishes to make the land should sail around it to the southwest and west, till he has come past all those places where ice may be looked for, and approach the land on that side."4

  Abundant cod and centuries of unusually mild conditions allowed the Greenlanders to voyage to North America and trade freely with Iceland and Norway in walrus ivory, wool, and even falcons. Their ships often carried exotic, valuable cargoes. In 1075, a merchant named Audun shipped a live polar bear from Greenland as a gift to King Ulfsson of Denmark. Four centuries later, no one would have dared carry such a cargo eastward. If not for the Medieval Warm Period, hundreds of years might have passed before anyone colonized Greenland and voyaged beyond its fjords.

  As the Medieval Warm Period dawned and the Vikings crossed to Greenland and North America, Europe was a patchwork of feudal states and warring lords, unified only by the Christian faith. King Charlemagne founded his Frankish empire in 800. The Holy Roman Empire came into being in 962 but offered little security. The Norsemen ravaged the northern coasts for more than two hundred years, then acquired a veneer of culture from the lands where they settled. Knut the Dane, or "Canute the Great" (1016-35), famous for his attempts to control the tides, presided over a North Sea empire that linked Britain and Denmark. William the Bastard, Duke of Normandy, conquered the kingdom of England in 1066. He parceled out his new domains among his Norman lords and created a feudal realm, a dense network of contractual relationships, which connected the highest to the lowest in the land. Not that the vagaries of the weather made William's task easier. Persistent northwesterly winds delayed his Channel crossing until October. Furthermore, two centuries of warm conditions had caused significant sea level rises. A shallow fjord extended deep into eastern England as far as Norwich. The lowlying English fenlands became a labyrinth of shallow channels and islands so difficult of access for an invader that the Anglo-Danish inhabitants of the city of Ely, led by Hereward the Wake, were able to hold off the Normans for a decade after 1066.

  For all the conquest and adventuring, Europe was a rural continent. Long before the
Romans tamed Britain and Gaul two thousand years ago, Europe's economy was anchored to the land and the sea, where the vagaries of floods, droughts, and severe winters affected everyone's economic fortunes. Several wet springs and cool summers in a row, a sequence of severe Atlantic winter storms and floods, a two-year drought-such brief climatic variations were sufficient to put people's lives at risk. The annual harvest drove everyone's fortunes, monarch and baron, small-town artisan and peasant. The generally stable weather of the Medieval Warm Period was an unqualified blessing for the rural poor and small farmers.5

  Summer after summer, warm settled weather began in June, and extended into July and August and through the hectic days of late summer. Medieval paintings tell the story of bountiful harvest. A French book of the seasons shows men and women in the March fields, in the shadow of strongly fortified castle walls. The fields are small, often divided into strips. Women and children crouch over furrowed land, pulling weeds before planting begins. In the foreground, a bearded man with leather hat and leggings plows a furrow with an iron-tipped plow drawn by two patient oxen. A shepherd and his dog drive a flock of sheep across fallow land toward the castle, while the leafless vines in a walled field under the walls stand still in the early spring day. In the lower corner, a peasant pours seed for planting into a waiting sack.

  The poor lived off the land, supplementing their harvests with fishing and hunting in dense forests. For the wealthy, hunting was a sport. Gaston Febus's Book of the Hunt, written in France in 1387, proclaims the author's expertise at hunting stags with dogs. The pictures depict lords pursuing their prey through forests, their dogs leaping for the kill. Other illustrations show how Febus used nets for trapping hares and foxes, with men hard at work spinning fine rope and fabricating nets of different grades, the finest being used for capturing pigeons, even songbirds. After the hunt, the hunters gathered for a fine feast in the open air, their horses grazing nearby, the dogs scavenging for scraps. The nobility had a passion for hunting with falcons. In a mid-thirteenth-century book on falconry published in Sicily, two falcon handlers with thick leather gauntlets display their birds, one of which is picking with its beak at its jess (tether).

  Despite wars, Crusades, schism and other strife, the Medieval Warm Period was a bountiful time for Europe. In the deep countryside, the even tenor of rural existence unfolded year after year. Life centered on the endless processions of seasons, on the routines of planting and harvest, cycles of good years and bad, and on the timeless relations between lords and their serfs. Innumerable tiny, largely self-sufficient hamlets nestled in remote valleys and on the edges of thick woodlands, their inhabitants living close to the soil, where everything depended on the bounty of summer harvests and the living one could wrest from the land.

  Most years passed with good harvests and enough to eat. Average summer temperatures were between 0.7 and 1.0°C above twentieth-century averages. Central European summers were even warmer, as much as 1.4°C higher than their modern averages. May frosts, always a hazard for warmth-loving crops, were virtually unknown between 1100 and 1300. The summer months were consistently sufficiently warm and dry for vineyards to spread across southern and central England, as far north as Hereford and the Welsh borders. Commercial vineyards flourished 300 to 500 kilometers north of their twentieth-century limits. During the height of the Warm Period, so many lords quaffed prime English wines that the French tried to negotiate trade agreements to exclude them from the Continent.

  Rural and urban populations rose sharply during medieval times. New villages sprang up on hitherto uncleared lands. Thousands of hectares of woodland fell before farmers' axes in a medieval practice called assarting. Warmer summers and mild winters allowed small communities to grow crops on marginal soils and at higher altitudes than ever before-350 meters above sea level on the hills of Dartmoor in southwestern England, on the Pennine Moors in the northeast, where, in the thirteenth century, shepherds complained about the encroaching cultivation of prized grazing range, and on the summits of southeastern Scotland's Lammermuir Hills, 320 meters above sea level. Today, neither Dartmoor nor the Pennine Moors support crops and the upper limit of cereal growth in the Lammermuirs is well below that of 1250. In 1300, one farm owned by Kelso Abbey in southern Scotland had over 100 hectares of land under cultivation, supported 1,400 sheep and sixteen shepherds' householdsall at 300 meters above sea level, well above today's limit. By the same year, thousands of farmers had settled on high ground and on marginal lands throughout England and Scotland, which placed them at risk of crop failure.

  In Scandinavia, settlement, forest clearance, and farming spread 100 to 200 meters farther up valleys and hillsides in central Norway, from levels that had been static for more than 1,000 years. Wheat was grown around Trondheim and hardier grains such as oats as far north as Malagan, at latitude 62.5° north. The height change hints at a rise in summer temperatures of about a degree Centigrade, a similar increase to that across the North Sea in Scotland. Farming became considerably easier in the Scottish highlands as a result, as forests spread outward into hitherto treeless environments. Far to the south in the Alps, tree levels rose sharply and farmers planted deeper and deeper into the mountains. During late prehistoric times, numerous copper mines had flourished in the Alps until advancing ice sealed them off. Late medieval miners reopened some of the workings when the ice retreated. Higher rainfall spread over much of southern Europe and the western Mediterranean. As a result, some Sicilian rivers were navigable in ways that would be impossible today. Medieval bridges, like the one in Palermo, still span them but are far longer than now necessary, simply because the rivers were wider nine hundred years ago.

  In theory, European society was well ordered. "Every man should have a lord," proclaimed the Treaty of Verdun in 843. Only the Pope and the Holy Roman Emperor in Constantinople were exempt from this stricture, and they were vassals of the Lord. In practice, feudal society was intensely hierarchical, a confused mass of conflicting dependencies and loyalties, intersected by exceptions and exemptions and ridden with constant litigation. At the local level, the lord of a manor granted a plot of land to each of his serfs in exchange for service as unpaid laborers on his demesne. Enserfinent implied a contract that traded land for service, protection for loyalty. Almost every rural European was conditioned by his or her position in a complex social order, hemmed in by legal and emotional ties of dependence that gave people some security but no personal freedom. But all on the land, lord and commoner alike, counted their blessings of fine weather and usually good harvests and attributed them to God's grace.

  In that devout age, everyone's fate was in the hand of the Lord. People lived at God's mercy, with only their piety to intercede for them, expressed in prayer and mortar. Gratitude came from chant and prayer, from lavish offerings and, above all, from a surge of cathedral building. The energetic Suger, Abbot of Saint Denis (d. 1151), was a shaper of European politics, an adviser to monarchs who even governed France when King Louis VII went on the Second Crusade. He found time to patronize the development of the soaring Gothic architectural style, where the skeletal structure of a cathedral held up a higher and lighter building, with more space for windows than earlier, more massive Norman churches.6 Gothic churches were towering frameworks of masonry columns or pillars, supported on the outside by flying buttresses. Their architects made brilliant use of stained glass to tell stories, to depict the Christian cosmos, with a great rose window over the front wall of the cathedral. The stone tracery gave the appearance of a rose, the brightly colored glass set in lead in an ancient symbol of human love transcending passion. Sculptures on the external and internal walls of the cathedral represented biblical stories, the four Gospels, the Last Judgment, and other manifestations of Christian belief. Abbot Suger himself appears as a small figure kneeling in prayer in a small corner of one of the stained glass windows of his own abbey, itself a masterpiece of Gothic artistry.

  The twelfth and thirteenth centuries were golden years of
architects, masons, and carpenters, who moved from cathedral to cathedral, taking their evolving ideas with them. They created works of genius: Notre Dame, on the Ile de le Cite in the heart of Paris, commissioned by Bishop Maurice de Sully in 1159 and built over two centuries; the ethereal places of worship at Rheims and Sens; the choir of Canterbury Cathedral in southern England, erected in the 1170s, and Lincoln to the north, a triumph of vaulting, begun in 1192. The ultimate aesthetic effect came at the Sainte-Chapelle in Paris, completed on April 25, 1248, smaller than the great cathedrals and "an edifice of exquisite delicacy and light, its tall, slender windows filled with brilliant expanses of stained glass." 7 Cathedrals are never completed, for they are built, then rebuilt, restored, added to, and sometimes abandoned or damaged in war by later generations. But the surge in Gothic cathedral building, financed by an outpouring of surplus resources, labor, and wealth, was never emulated in later centuries.

  Every civilization expresses itself through its great works. They are society's most tangible statement of what is important enough to have scarce resources lavished upon it. The Pyramids of Giza in Egypt were built at enormous expense as symbolic ladders to heaven for the divine pharaohs who were buried in them 4,500 years ago. Aztec rulers of ancient Mexico laid out their fifteenth-century capital, Tenochtitlan, "the Place of the Prickly Pear Cactus," in the center of their vast empire as a depiction in stone and stucco of their cosmos. Our industrial and commercial age erects universities and museums, huge concert halls and stadiums, railroads, highways, and the World Wide Web. Medieval Europeans built cathedrals. The cathedral was an act of piety, a wondrous monument, a museum. Perhaps endowed with a sacred relic, a miraculous image, or a sign of martyrdom, a cathedral at Canterbury, York or Chartres was a tangible symbol of the imminent presence of God. Even in good years, medieval Christians worried about harvests, the fertility of the land, the continuity of life itself. Cathedrals were the Bible of the illiterate poor, built in an image of the cross and of the Body of Christ. Each represented a corner of God's kingdom. They were expensive outpourings of love for the Lord, sacrifices of stone and material goods offered in the expectation of divine favor.