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Volume 29, Number 5September/October 1978

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Whither the Weather

Written by William J. Griswold
Illustrated by Michael Grimsdale

In the mid-1970's, weather - or, more accurately, climate - suddenly seemed to emerge as a new factor in the history of mankind. In the wake of summer droughts in Europe, heavy rains in arid Saudi Arabia, a disastrously dry winter in the Rocky Mountains, savage blizzards in New England and the deadly spread of deserts in Africa, meteorologists and others have begun to crank out articles, books and novels on the subject of climate. Some writers, openly alarmist, predict that a new Ice Age is upon us, while others, looking to sales, darkly blame nuclear explosions or hint at imaginative conspiracies. Even the more restrained observers suggest that changes in weather patterns will have a disturbing impact on modern history.

Actually, weather has always played an important role in history. On August 20 in AD. 636, for example, a perverse change in the weather helped determine the outcome of a battle in Syria that, in turn, became a watershed in the history of the Middle East.

The battle, which took place on the Yarmuk River near the Golan Heights in southern Syria, pitted the armies of the Byzantine emperor Heraclius against thousands of Muslim Arabs, and the outcome - a resounding Arab victory - reshaped the known world. For Arab victory that day erased forever the power of Byzantium in Syria, and opened the way for the subsequent conquest of Egypt and all of North Africa by the armies of Islam. Eventually the victory at Yarmuk also opened the eastern Mediterranean to the Umayyad dynasty, led to the conquest of Spain and, still later, to three sieges of the greatest Christian city: Constantinople. The memory of the glorious day at Yarmuk would even echo in the 20th-century Arab struggle against colonialism.

Yet for all the brilliance of the Arab commanders at Yarmuk and the heroism of the Islamic warriors, a key factor in the battle of the Yarmuk River was a change in the weather. Blowing with gale force, southeast winds on that August day drove clouds of sand and grit into the eyes of the Byzantine soldiers, blinding them to the attack of the Arab warriors, who had the wind at their backs, preventing them from launching a counterattack and rendering the usual tactics of the battle-proven Byzantine commanders useless. Their troops turned to flee, leaving the field and the victory to the Arab warriors of the new faith.

Such perversity of weather is not uncommon in the history of the Middle East. In 717 the Umayyad dynasty, bent on conquering Constantinople, was turned back as much by the fickleness of miserable winter weather as by the Byzantines' secret weapon - "Greek fire" - and the great rampart system surrounding the city. In 1098 unseasonable cold nearly thwarted the first European Crusaders' siege of Antioch, and in 1529 one Ottoman sultan - Suleiman the Magnificent - turned back from Vienna after unseasonable rainstorms in the Danube Valley bogged his cannon down in the mud. Half a century later the Christian Holy League defeated the Ottomans in a naval battle at Lepanto, but could not follow up their advantage because of a severe storm on the morrow of the victory.

Commanders of those periods, of course, had no weather satellites to help them time their campaigns, but they were, nevertheless, acutely aware that weather could have catastrophic effects on their plans and they did what they could. From earliest times, they attempted to placate the gods, sought the opinions of soothsayers and astrologists, and called upon various holy men to ascertain weather conditions. But such activities provided only psychological solace, not practical help. Until the technology of our own time, developed for the most part since World War II, military commanders could do little more than hope that the weather would favor them, or philosophically accept the results. The same was true of farmers too; even more than soldiers, farmers knew the impact of weather. But they had no remedies either.

Today, modem science is gradually changing this state of affairs. The scientific revolution has not only provided a rational understanding of curious and perverse weather changes but, by averaging out such changes, discerned predictable patterns of climate. Gathering together barometric, temperature and rainfall data in many parts of the world over many decades, meteorologists have determined that climate - the long-term accumulation of weather changes - occurs in definable patterns. If carefully analyzed, these patterns may foretell what the inhabitants of a certain region can generally expect over a period of days and even months. Such data can also give insights into the climatological probabilities for the future - perhaps even years ahead.

Recently, for example, meteorologists have cautiously suggested that the relatively fine climate of the past 50 or 60 years on the North American continent may be abnormal and passing and that the climatic patterns of the atmosphere may be drastically changing. These suggestions - which led to the spate of articles, books and novels on climate - were based on changes in the accustomed patterns: the rains in Saudi Arabia in 1976, a dry winter in the Rocky Mountains in 1976-1977, severe cold spells that same year in the eastern United States and, for some areas of North America, the savage 1977-78 winters. Such changes in the weather may indeed presage a distinct climatic alteration in the northern hemisphere. But they are not the result of atomic testing or infamous scientific conspiracies; they are natural climatic patterns forming in response to the constant motion of the earth's atmosphere.

The important fact to remember is that, unlike the political sphere, the atmosphere is truly one world: a unity of temperature changes, low pressure and high pressure areas and wind variations which circulate from west to east over the northern half of the globe. As British meteorologist J. M. Craddock put it, "Climate is made up of super-imposed fluctuations of the general atmospheric circulation, and not of independent random variations." By quantifying the fluctuations, storing the data and processing it in computers, meteorologists - after certain breakthroughs - may soon be able accurately to describe general climatic patterns and - an exciting possibility - predict the extent to which we can make demands on the environmental system.

Climate, together with human demands on the environment, has already had an immense, if not always recognized, impact on the history of the Middle East Herdsmen, for example, have let their goats and sheep overgraze Middle East pasture lands for millennia, and both armies and priesthoods have stripped such regions as ancient Anatolia and Syria of their forests. Combined with climatic changes over the same periods, such practices transformed many areas - where civilizations once flourished - into useless deserts.

Where exceptional individuals learned or foresaw impending changes in climate and were able to take action, the results were quite different Noah, for example, was alerted to the Flood - possibly a result of storms in the region of Iraq with the addition of melting snow from the Caucasus Mountains - and miraculously understood what his neighbors obviously did not: that such climatic variations can change men's lives - and in a remarkably short time.

Another example - from both the Bible and the Koran - is Joseph, who laid aside seven years' worth of food in Egyptian granaries in preparation for a coming period of famine. Joseph implicitly recognized the decreasing productivity of the soil resulting from a discernible climatic variation: the slow but inevitable course of desiccation - similar to that now taking place in Africa.

Both Noah and Joseph, however, were exceptional. Their contemporaries, on the other hand, were not Like Californians who continue to build homes on the unstable brinks of canyons, they stubbornly refused to believe that the changes in climate were anything more than temporary aberrations. Noah's people stayed where they were and Joseph's brethren acted as nomadic peoples always do. Faced with the fact of desiccation, and not realizing how migration complicates matters - newcomers are seldom welcome during famines - they moved on. Existing in any case on a narrow margin of economic subsistence, nomads normally migrate from the drier regions to the more verdant and when extraordinary variations in climate occur, mass movement toward more fertile regions is inevitable - with results that are politically devastating. The Persian-Turanian enmity, lasting for centuries and dearly articulated in the 10th-century epic Shah-name (The Book of Kings), may be an example of this; it seems to have had its roots in just such extraordinary pressures by the nomadic Turanian cultures on the urban Persian civilization. Because climatic variations apparently dried up their normal grazing grounds, various Turkish tribes east of the Oxus River pushed west, crossed the natural boundary of the river, and swarmed over portions of pre-Islamic Persia's urban culture.

At the other end of the climatic spectrum, excessively moist years in normally vegetated areas can create abnormally rich nutrients for mosquitoes, grasshoppers or rodents and, as a result, lead to deadly plagues. In the Middle Ages the fertile oasis of Damascus in Syria had a continuing reputation for being plague-ridden, probably malarial. And although an abundance of water is of course vital to agriculture, it can also result in the spread of liver flukes which carry the disease called bilharzia, a problem in Egypt and some other Middle Eastern countries.

The most common misery and the worst suffering attributable to unexpected climatic variations are those which arise when climatic change alters vast agricultural regions generally considered fertile - the so-called "breadbaskets." Every pre-modern Middle East power had its major source of food: the Byzantines' was Anatolia and Syria; the 'Abbasids had the lower Tigris-Euphrates region plus Khurasan and Bukhara; and the Ottomans possessed Egypt. But there was also an inherent political danger in such agricultural dependence, and it eventually materialized. When climatic patterns changed, the farmers, unable and unwilling to migrate, could be provoked into rebellion against the established authorities. Nomads could move on, but for sedentary peasants, flight from their ancestral homes was simply not an acceptable alternative.

One example of political upheaval possibly rooted in climatic variations is the Jelali revolts of the late 16th century in Ottoman Anatolia. Following a period of several decades of poor growing seasons and severe desiccation, the Anatolian peasants rebelled for more than a dozen years, striking terror into the Ottoman government and almost severing Anatolia from the Empire.

Admittedly the causal relationships between the desiccation of Anatolia and the Jelali revolts cannot be proved conclusively. It is, exceptionally difficult to prove a relationship between climate variation and social change in early periods of history. This is partly because present technical expertise cannot determine the actual climatic patterns for former times and partly because historians cannot accurately assess contemporary reports on the events. Historians do know something about the Anatolian peasants of the late 16th century, but the evidence is limited, nevertheless, to reports from foreign travelers and resident consuls, plus a few Ottoman documents. And even with reports from witnesses there are difficulties in establishing accurate factual guidelines. How, for example, can historians evaluate this statement of a 17th-century Venetian consul on viewing the Anatolian plain: "... the land is unpopulated and is not productive..."? Or the writing of an English traveler: "... a man may walke many a mile through the Turkes Country and find neither men nor houses..."? Obviously, something about the region appeared strange, or the Venetian and the Englishman would not have commented. But it is still impossible to say whether a drop in productivity and population derives from climatic conditions, governmental heavyhandedness, or some other cause. Or to say definitely that peasants migrate because changes in the climate, rather than politics, have forced them to move.

In attempting to prove that climate is a cause, research in the works of modem historians of the Middle East is of little help. These writers hardly ever identify climatic conditions, even when they are mentioned in the sources used. Philip Hitti, for example, whose standard History of the Arabs covers 1,400 years and utilizes many of the great Arab sources and chroniclers, mentions important weather-related issues only a dozen times or so. Specialized works, like Guy le Strange's Baghdad During the Abbasid Caliphate, make some remarks about the floods which inundated the 'Abbasid capital at least once every decade for a period of 400 years, but they are tantalizingly few.

Nevertheless, the possibility that climate and political upheaval are linked remains a fascinating hypothesis and certain historians of the Arabs have begun to explore it Professor William Tucker of the University of Arkansas has studied the effects of climate in the records of Mamluk Egyptian history and learned that historians and chroniclers of Egypt from 661 to 1500 often mention the occurrence of abnormal floods and famines. He has also come up with information about heavy rains in Cairo in the 1290's and 1340's, and about excessive droughts in the years 1304 and 1427; he points out that climate-related information dearly exists in the Arabic historical writings of al-Tabari, Ibn al-Athir, al-Maqrizi, and others.

In addition, modern meteorology is beginning to offer methods and tools which, when perfected, will tell historians much more about the past Specialists called paleoclimatologists - historians of the dimatological past - have begun to chart various climatic patterns which have affected human behavior since early times. And exact knowledge of wind patterns, as they circulate around the earth, may explain some developments of the past. Such studies have already shown that certain mountain ranges act as huge dams which funnel the air, and life-giving rain, into some regions, but force it away from others - thus creating deserts and aridity. Technology, of course, can make the desert bloom - as it has in Saudi Arabia - but the desert, because of the physical structure of the globe, will remain a desert.

Meteorologists, moreover, can now chart Middle East climatic patterns over periods of decades. With the aid of computers, they can establish trends of the past, based on certain repetitive patterns. Knowledge of shifting high and low pressure areas, which provoke unexpected changes - expansion of the desert in northern Africa, dry winters in Anatolia, rain in Saudi Arabia, and so on can, when put in the context of proven weather data from many world-wide centers, establish a configuration from which dimatologists can deduce past patterns of "normal" climatic modes. From this "norm" they can better understand the variations and deviations which cause the "weather changes" which affected the people of at least the recent past.

The paleoclimatologist remains forever stymied, of course, in his quest for perfect understanding of the patterns of ancient times. He simply cannot obtain accurate climatic data from the past. He must rely on a variety of other related technologies. One important study is that of glacial changes, especially in those areas where changes in glacier size can be verified.

The best examples of this are the glaciers of western Europe: especially the Rhone region and the Grindelwald Glacier, which has been written about, sketched, and - more recently - photographed for the past 300 years. On the basis of such research, paleoclimatologists can say that Europe suffered a "Little Ice Age" from about 1550 to 1850, a climatic change which probably affected Europe's society and economic history every bit as much as the gold and silver newly arrived from the Americas or the collapse of the Ottoman Empire.

Another important study is the direction, strength and changing patterns of the monsoons, particularly those in the Arabian Sea. From this study scholars expect to deduce how these variations, over a period of centuries, forced changes in trade relationships, weakened the naval operations of some powers and strengthened those of others. In recent years, scientists have also improved their ability to learn about the relative dryness of regions in the historical past by analyzing tiny bits of pollen found in bricks, mortar or tombs. And today they are on the verge of a breakthrough by which they may be able to provide chronological data: year-by-year information which could verify assumptions about climate changes in the past. By adapting the carbon dating methods of archeologists, they may soon be able to unlock the secrets of the dimatological past.

Dating organic materials has, since Willard Libbys discovery of an accurate way to use the half-life of carbon-14, helped to establish a reliable chronology of some very ancient objects: pieces of ships or the age of grains of wheat. And today dendrochronologists can not only date various pieces of wood - by counting the rings formed in tree growth - but can also show periods of heavy rain or desiccation by measuring and analyzing the rings. Professor Peter Kuniholm of Cornell University's Department of Classics, for example, has made several trips to Anatolia, where he has not only established an absolute annual chronology in trees for the past seven centuries, but now can show, with some accuracy the amount of water available for trees during certain periods.

This opens an exciting possibility: that, given more tree rings and more verifiable information from the rings, science may be able to match the social changes of a period, known from the contemporary written records, with discernible periods of climatic variation. Applied to the Jelali rebellions of Anatolia, this method would compare tree-ring data with the reports of travelers and consuls and with the Ottoman records and either verify or disprove the hypothesis that a 20-year climatic change was at the root of the rebellion. Such accurate dating might also ascertain that certain regions of Anatolia suffered severe drought for more than a decade, thus providing the impetus for the conservative Anatolian peasants to leave the land and, in desperation, take up arms in rebellion against the sultan's government. It could even disclose whether, in other periods of Anatolian history, similar climatic variations changed social conditions so drastically that a unique Anatolian personality developed as a result of these forces.

Still another method of applying meteorology to the study of history in the Middle East has come from the fertile imagination of a group of paleoclimatologists who are often considered mavericks by their colleagues. One of the most exciting of these is Professor Reid Bryson of the University of Wisconsin, who has suggested the use of modern patterns of climate as guides to our understanding of the climatic patterns of the past.

Assuming, as all meteorologists do, that the world of climate is one, or that, as Stephen Schneider says in The Genesis Strategy, "... a kick in one spot of the world will cause a bulge in another," Bryson reasons that science should be able to find enough data in the past to ascertain that patterns similar to those of the present existed then. Taking the example of the great Mediterranean Greek civilization of Mycenae - which abruptly fell about 1200 B.C. - Bryson established some guideposts from relatively verifiable data of that same historical period but in different parts of the globe: an emigration of people from Libya to Egypt, a series of horrendous floods in Hungary an abnormal rising of the Caspian Sea, and so on. Why did the Mycenaean people leave? Was it an invasion of Dorians from the north?

Bryson suggests that the central Greek drought pattern of 1200 B.C. may have been analogous to another drought in the same region during the winter of 1954-1955. He then proceeded to toy with this hypothesis: that Mycenae, like the Greek mainland of 1954-1955, suffered a period of dryness; that under such circumstances it would have been difficult to sustain agriculture; and that given the social conditions and alternatives of 1200 B.C., the drought, rather than a Dorian invasion, forced the Mycenaeans to move away.

For historians of the Middle East, the technique of analogous climatic variations might explain many mysterious events. It might establish more accurately the cause of the overland movement of masses of people from the Far East to the West in successive waves, vast dominions tripping over one another from the fifth-century Huns to the 11th-century Seljuk Turks and the 13th-century Mongols. Even more importantly, this approach might offer advance warnings of climatological changes that would demand political and humanitarian cooperation. A good example of this is the recent desertification of the Sahel in north central Africa, where overgrazing plus a variation in climate patterns produced almost six years of famine conditions. Alerted in time, governments might have imposed restrictions on grazing, fenced off lands, or taken other steps to avoid or at least mitigate this ecological disaster.

Obviously, climate will vary whether the world does anything about it or not. But by anticipating the variations, and acting in time - as Joseph did in Egypt and as modern science is learning to do today - man might ease the burdens that harsh climate and difficult terrain have historically imposed upon him.

William J. Griswold earned his Ph. D. at the University of California in Los Angeles. He now teaches Middle East history and Islamic cultural history at Colorado State University. He is also a member of the Middle East Studies Association and General Secretary of the Turkish Studies Association.

This article appeared on pages 22-27 of the September/October 1978 print edition of Saudi Aramco World.


Check the Public Affairs Digital Image Archive for September/October 1978 images.