The Little Ice Age: How Climate Made History 1300-1850 Page 6

  By 1317, as the rains continued through another wet summer, people everywhere despaired. The church performed complex rogation ceremonies to pray for divine intervention. Guilds and religious orders in Paris processed barefoot through the streets. In the dioceses of Chartres and Rouen, chronicler Guillaume de Nangis saw "a large number of both sexes, not only from nearby places but from places as much as five leagues away, barefooted, and many even, excepting the women, in a completely nude condition, with their priests, coming together in procession at the church of the holy martyr, and they devoutly carried bodies of the saints and other relics to be adored."" After generations of generally good harvests and settled weather, they believed divine retribution was at hand for a Europe divided by wars. Rich and poor alike endured the punishment of God.

  The famine brought an outpouring of religious fervor and, for some, profit. Canterbury Cathedral with its wealthy priory attracted streams of pilgrims, many of them poor travelers in holy orders. The priory had an honorable tradition for charity. Its budget had run at a deficit because of its generosity, showing only four years with modest surpluses between 1303 and 1314. In 1315, the monks made an unexpected profit of £534, despite the famine. Their wheat yields were as bad as anyone else's, but they were able to sell considerable amounts of oats. Their real profit came from £500 worth of offerings to the priory by pilgrims praying for better weather. In 1316, the monks found themselves in the same position as everyone else, with significant grain shortfalls and a need to pay much higher prices for anything they could not produce for themselves. They also faced a moral dilemma. The priory was besieged by poor pilgrims seeking relief. Yet offerings were off by 50 percent. Rents from the priory estates had declined by nearly half, but the house could not reduce its level of relief without affecting its good reputation among the devout. At the same time, consumption of communion wine had increased twofold owing to the increased level of devotions. The monks resorted to cost-cutting measures reminiscent of modern times. They curtailed pensions, delayed essential maintenance on buildings, and postponed costly lawsuits.

  The priory's problems were compounded by increased royal taxation to pay for wars with the Scots. King Edward I had conquered Wales between 1277 and 1301 and secured it with a line of castles from Harlech to Conway. He had also invaded Scotland unsuccessfully to intervene in a succession dispute. Edward's poorly timed intervention provoked a Scottish bid for total independence. He was succeeded by Edward II in 1307, whose army was defeated by Robert the Bruce at the Battle of Bannockburn in 1314. Warfare continued until 1328, when the Scots prevailed. The cost for the English was enormous, at a time of great suffering. Royal taxation fell heavily on a hungry populace and on Canterbury priory. The monks still managed to produce plenty of high-priced oats, but most of their carefully thought out savings were eaten up not by pilgrims but by the new taxation for Scottish wars. However, the priory's refusal to cut relief soon rebounded in its favor. When the harvest improved in 1319, offerings promptly skyrocketed to a record £577. The monks received so many sacred relics for a cathedral already well endowed with such artifacts that they sold them off for over £426. It was well they had plenty of money in hand, for cattle disease struck in 1320, with devastating effects on the surrounding area. Fortunately, offerings reached over £670, as people prayed for relief, and the priory weathered the crisis.

  The suffering lasted for seven years before more normal harvests brought a measure of relief. Horrendous weather continued through 1318, with extensive flooding in the Low Countries in 1320 and 1322. The cycle ended in 1322 with a reversal of the NAO, which brought a bone-chilling winter that immobilized shipping over a wide area while thousands more perished from hunger and disease. The settled climate of earlier years gave way to unpredictable, often wild weather, marked by warm and very dry summers in the late 1320s and 1330s and by a notable increase in storminess and wind strengths in the English Channel and North Sea. The moist, mild westerlies that had nourished Europe throughout the Medieval Warm Period turned rapidly on and off as the NAO oscillated from one extreme to the other. The Little Ice Age had begun.

  COOLING BEGINS

  -Second shepherd, Second Towneley Shepherd's Play, part of the Wakefield Cycle, c. 1450

  Through climatic history, economic history, or at least agrarian history, is reduced to being `one damn thing after another.'

  -Jan de Vries

  "Measuring the Impact of Climate on History, " 1981

  Glacier oscillations of the last few centuries have been among the greatest that have occurred during the last 4,000 years perhaps ... the greatest since the end of the Pleistocene ice age.

  -Francois Matthes

  "Report of Committee on Glaciers, " 1940

  ifteen thousand years have passed since the end of the last glacial episode of the Great Ice Age. Since then, through the Holocene (Greek: recent) era, the world has experienced global warming on a massive scale-a rapid warming at first, then an equally dramatic, thousand-year cold snap some 12,000 years ago, and since then warmer conditions, culminating in a period of somewhat higher temperatures than today, about 6,000 years before present. The past 6,000 years have seen near-modern climatic conditions on earth.

  Like the Ice Age that preceded it, the Holocene has been an endless seesaw of short-term climate change caused by little-understood interactions between the atmosphere and the oceans. The last 6,000 years have been no exception. In Roman times, European weather was somewhat cooler than today, whereas the height of the Medieval Warm Period saw long successions of warm, settled summers. Then, starting in about 1310 and continuing for five and a half centuries, the climate became more unpredictable, cooler, occasionally stormy, and subject to sporadic extremes-the Little Ice Age.

  "Little Ice Age" is one of those scientific labels that came into use almost by default. A celebrated glacial geologist named Francois Matthes first used the phrase in 1939. In a survey on behalf of a Committee on Glaciers of the American Geophysical Union, he wrote : "We are living in an epoch of renewed but moderate glaciation-a `little ice age' that already has lasted about 4,000 years."' Matthes used the term in a very informal way, did not even capitalize the words and had no intention of separating the colder centuries of recent times from a much longer cooler and wetter period that began in about 2000 B.C., known to European climatologists as the Sub-Atlantic. He was absolutely correct. The Little Ice Age of 1300 to about 1850 is part of a much longer sequence of short-term changes from colder to warmer and back again, which began millennia earlier.

  The harsh cold of Little Ice Age winters lives on in artistic masterpieces. Peter Breughel the Elder's Hunters in the Snow, painted during the first great winter of the Little Ice Age in 1565, shows three hunters and their dogs setting out from a snowbound village, while the villagers skate on nearby ponds. Memories of this bitter winter lingered in Breughel's mind, as we see in his 1567 painting of the three kings visiting the infant Jesus. Snow is falling. The monarchs and their entourage trudge through the blizzard amidst a frozen landscape. In December 1676, artist Abraham Hondius painted hunters chasing a fox on the frozen Thames in London. Only eight years later, a large fair complete with merchants' booths, sleds, even ice boats, flourished at the same icebound location for weeks. Such carnivals were a regular London phenomenon until the mid-nineteenth century. But there was much more to the Little Ice Age than freezing cold, and it was framed by two distinctly warmer periods.

  A modern European transported to the height of the Little Ice Age would not find the climate very different, even if winters were sometimes colder than today and summers very warm on occasion, too. There was never a monolithic deep freeze, rather a climatic seesaw that swung constantly backwards and forwards, in volatile and sometimes disastrous shifts. There were arctic winters, blazing summers, serious droughts, torrential rain years, often bountiful harvests, and long periods of mild winters and warm summers. Cycles of excessive cold and unusual rainfall could last a decade, a few years, or jus
t a single season. The pendulum of climate change rarely paused for more than a generation.

  Scientists disagree profoundly on the dates when the Little Ice Age first began, when it ended, and on what precise climatic phenomena are to be associated with it. Many authorities place the beginning around 1300, the end around 1850. This long chronology makes sense, for we now know that the first glacial advances began around Greenland in the early thirteenth century, while countries to the south were still basking in warm summers and settled weather. The heavy rains and great famines in 1315-16 marked the beginning of centuries of unpredictability throughout Europe. Britain and the Continent suffered through greater storminess and more frequent shifts from extreme cold to much warmer conditions. But we still do not know to what extent these early fluctuations were purely local and connected with constantly changing pressure gradients in the North Atlantic, rather than part of a global climatic shift.

  Northern Hemisphere temperature trends based on ice-core and tree-ring records, also instrument readings after c. 1750. This is a generalized compilation obtained from several statistically derived curves.

  Other authorities restrict the term "Little Ice Age" to a period of much cooler conditions over much of the world between the late seventeenth and mid-nineteenth centuries. For more than two hundred years, mountain glaciers advanced far beyond their modern limits in the Alps, Iceland and Scandinavia, Alaska, China, the southern Andes and New Zealand. Mountain snow lines descended at least 100 meters below modern levels (compared with about 350 meters during the height of the late Ice Age 18,000 years ago). Then the glaciers began retreating in the mid- to late nineteenth century as the world warmed up significantly, the warming accelerated in part by the carbon dioxides pumped into the atmosphere by large-scale forest clearance and the burgeoning Industrial Revolution-the first anthropogenic global warming.

  Climate change varied not only from year to year but from place to place. The coldest decades in northern Europe did not necessarily coincide with those in, say, Russia or the American West. For example, eastern North America had its coldest weather of the Little Ice Age in the nineteenth century, but the western United States was warmer than in the twentieth. In Asia, serious economic disruption, far more threatening than any contemporary disorders in Europe, occurred throughout much of the continent during the seventeenth century. From the 1630s, China's Ming empire faced widespread drought. The government's draconian response caused widespread revolt, and Manchu attacks from the north increased in intensity. By the 1640s, even the fertile Yangtze River Valley of the south suffered from serious drought, then catastrophic floods, epidemics, and famine. Millions of people died from hunger and the internecine wars that resulted in the fall of the Ming dynasty to the Manchus in 1644. Hunger and malnutrition brought catastrophic epidemics that killed thousands of people throughout Japan in the early 1640s. The same severe weather conditions affected the fertile rice lands of southern Korea. Again, epidemics killed hundreds of thousands.

  Only a few short cool cycles, like the two unusually cold decades between 1590 and 1610, appear to have been synchronous on the hemispheric and global scale.

  Unfortunately, scientifically recorded temperature and rainfall observations do not extend back far into history-a mere two hundred years or less in Europe and parts of eastern North America. While these incomplete readings take us back through recent warming into the coldest part of the Little Ice Age, they tell us nothing of the unpredictable climatic change that descended on northern Europe after 1300.

  Some methods used to study the Little Ice Age

  Reconstructing earlier climatic records requires meticulous detective work, considerable ingenuity, and, increasingly, the use of statistical methods. At best, they provide but general impressions, for, in the absence of instrument readings, statements like "the worst winter ever recorded" mean little except in the context of the writer's lifetime and local memory. Climatic historians and meteorologists have spent many years trying to extrapolate annual temperature and rainfall figures from the observations of country clergymen and scientifically inclined landowners from many parts of Europe. Extreme storms offer unusual opportunities for climatic reconstruction. On February 27, 1791, Parson Woodforde at Weston Longville, near Norwich in eastern England, recorded : "A very cold, wet windy day almost as bad as any day this winter." Synoptic weather charts reconstructed from observations like Woodforde's reveal a depression that brought fierce northeasterly winds of between 70 and 75 knots along the eastern England coast for three days. The gale brought the tides on the Thames "to such an amazing height that in the neighborhood of Whitehall most of the cellars were underwater. The parade in St. James's Park was overflowed." Thames-side corn fields suffered at least .£20,000 worth of damage.2

  Fluctuating grain prices are another barometer of changing temperatures, in the sense that they can be used to identify cycles of unusually wet or dry weather that brought poor harvest in their train. Economic historians like W. G. Hoskins have tracked grain prices over many centuries and chronicled rises of 55 percent to as much as 88 percent above normal at times of scarcity, when hoarders and merchants stockpiled grain with an eye to a windfall profit or cereals were just in short supply. In countries like Britain or France, where bread was a staple, such rises could be catastrophic, especially for the poor. In the social disorders that usually followed, farmers lived in fear of their crops being pillaged before they were ripe, and mobs descended on markets to force bakers to sell bread at what they considered to be fair prices. Monastery records and the archives of large estates are a mine of information about harvests good and bad, about prices and yields, but, like most early historical sources, they lack the precision of a tree-ring sequence or an ice core. Annalists would write of heavy rain storms that "in many places, as happens in a flood, buildings, walls, and keeps were undermined," but such vivid descriptions are no substitute for reliable daily temperature readings.3

  The dates of wine harvests, derived from municipal and tithe records, also vineyard archives, provide a general impression of cooler and warmer summers, with the best results coming from linking such information with readings from tree rings and other scientific sources. The climate historian Christian Pfister focuses on two crucial months that stand out in colder periods: cold Marches and cool and wet Julys. Such conditions marked 1570 to 1600, the 1690s, and the 1810s, probably the coldest decades of the Little Ice Age.4

  Climatic historians are ingenious scholars. For instance the Hudson's Bay Company insisted that its captains and factors in the Canadian Arctic keep weather records on a daily basis even at its most remote stations. Since the same employees often worked for the company for many years, the records of ice conditions and of the first thaw and snowfall are remarkably accurate for the late eighteenth and early nineteenth centuries, to the point that you can track annual fluctuations in first snowfall and the beginning of the spring thaw to within a week, even a few days, over long periods of years. Spanish scholars are using the records of rogation ceremonies performed to pray for rain or an end to a deluge. Rogation rituals were rigorously controlled by the church and unfolded at various levels, culminating in years of crisis in formal processions and pilgrimages. Thus, they provide a crude barometer of climatic fluctuations.

  Historical records like these clearly display minor fluctuations between decades, but how they relate to broader climate change is a matter for future research. In recent years, statistical methods are being used to test indices developed from historical sources against tree-ring and other scientific climatic data. From such tests we learn, for example, that sixteenth-century central Europe was cooler at all seasons than the period 1901 to 1960, and that winters and springs were about 0.5° cooler, with autumn rainfall about 5 percent higher. Almost uninterrupted cold winters settled over the area between 1586 and 1595, with temperatures about 2°C cooler than the early twentieth-century mean. The same indices proclaim 1691-1700 and 1886-95 as the coldest decades in Switzerland o
ver the past five centuries.

  For all the richness and diversity of archival records, we have to rely in large part on scientific sources for year-by-year climatic information on the Little Ice Age. This record comes in part from ice cores, sunk deep into the Greenland ice cap, into Antarctic ice sheets, including one at the South Pole, and into mountain glaciers like that at Quelccaya in the southern Andes of Peru. Ice-core research bristles with highly technical difficulties, many of them resulting from the complex processes by which annual snowfall layers are buried deeper and deeper in a glacier until they are finally compressed into ice. Scientists have had to learn the different textures characteristic of summer and winter ice, so they can assemble a long record of precipitation that goes back deep into the past. Snowfall changes are especially important because they provide vital evidence on the rate of warming and cooling during sudden climatic changes.

  Two cores from the Greenland ice cap, known as GISP-1 and 2, are of particular interest for the Little Ice Age. GISP-2 has an accuracy in calendar years of ±1 percent, which makes it exceptionally useful for dating temperature changes, themselves identified by changes in the isotopic signal of deuterium (D) from year to year, even season to season. Lower isotopic excursions signal low temperatures, such as those in Greenland during the fourteenth century, where winters were the coldest they have been over the past seven hundred years. Ice-core climatic reconstructions offer great promise for studying the short-term cycles of warmer and colder conditions that affected the medieval Norse settlements in Greenland.

  Until the 1960s, tree-ring research was largely confined to the Southwestern United States, where astronomer Andrew Douglass achieved sci entific immortality by dating ancient Indian pueblos from the annual growth rings in desiccated wooden lintel beams. Since then, thousands of tree-ring sequences have come from the Southwest, to the point that experts can trace the year-by-year progression of serious droughts across the region 1,000 years ago. Originally, tree-ring dating was applied only in areas with markedly seasonal rainfall, but the science is now so refined that we have highly accurate sequences from German and Irish oaks going back at least 8,000 years.