Since the last great ice age (which ended c.10,000 years B.C.), followed by our current Holocene – a period, favourable for man – the planet has passed through several phases of striking climate changes, directly affecting man’s life (see Climate Oscillations in Holocene). Climate is one of the most important environment-shaping factors. Not only does climate determine landscape and its features, and shape the animal and plant kingdom, but it also defines the possibilities for the development of agriculture, demography, and migrations of entire peoples. Its global changes have been frequently accompanied by rises and falls of ethnoses, states, and civilisations, vehement strife for resources, and the spread of deviations like famines or epidemics.
For 12,000 years global temperatures have oscillated within the range of 0.5 °C to 2 °C. These seemingly inconsiderable changes have had disastrous consequences. For one, a fall of 0.5 °C brought about regional drops of temperature by 8 to 10 °C, and caused other extreme conditions.
Among the numerous theories seeking to account for mankind’s activity by climate changes, there is one which postulates that colder periods mobilized man’s strength, habits, and skills to overcome unfavourable climate conditions. It argues that such periods usually coincide with the epochs of the rise and flourishing of empires, the centralization of power, and breakthroughs in technology and science. Conversely, warmer periods were conducive to people’s moral and psychological relaxation, stagnation of technology, and the weakening and disintegration of state power mechanisms.
Despite a certain degree of formality of this climatic determinism, the role of natural factors in the development of human civilisations should not be overlooked. Climate has typically appeared as one of a few factors, a natural impetus of sorts which, in combination with other factors, has resulted in certain social changes.
EXTREME CONDITIONS AND MIGRATIONS
It is under cold climatic conditions that civilisations arose. The colder climate of 4,000 years B.C. stirred up state-building processes in Egypt, Mesopotamia, and India. Statehood helped ancient societies better cope with elements and natural calamities by fostering the construction of complex irrigation systems in the valleys of great rivers and the creation of supply chains. Consequently, such states were better off than scattered, stateless tribes.
Economically, man had for a long time totally depended on nature and the climate (in particular, on seasonal temperature oscillations and rainfall). Natural factors dominated the development of agriculture, which formed the basis of the economy until the 19th century, and influenced social and political stability and demographics. Crop failures due to natural and meteorological changes caused famines, outbursts of epidemics, dropping fertility rates, and even political calamities (uprisings, revolts, civil wars, revolutions, etc.).
Extreme climatic conditions are known to have caused the migrations of entire peoples who were forced to leave their habitats due to poor harvest and famine and look for resources in order to survive. Historians registered 15 great migrations of tribes and peoples between 3100 and 500 B.C., caused by deteriorating climate conditions. Of these, 13 migrations have been attributed to global cooling and two to global warming. Some examples can be found in the Aryan invasion of Hindustan out of drought-stricken Central Asia, which allegedly destroyed the highly developed Indo-Harappan civilisation and gave rise to the Indo-European peoples; the Dorian invasion of Crete, which put an end to the Minoan civilisation; the settlement of Phoenicians in the Mediterranean and Etruscans in Italy; and even Old Testament Jews’ moving to Egypt in search of salvation (fertile lands). The climate was clearly not the only factor, but it contributed to triggering the migration processes.
Historians have attributed the rise of nomadic societies which populated almost the entire Eurasian continent by the beginning of our era to a considerable drying of the climate in the mid-2nd – early 1st millennium B.C., caused by global cooling. Central Asian steppes had for a long time been an ethnic melting pot of sorts, which overflowed with several dozen of militant nomadic peoples. Climatologists deem it to be one of the planet’s most sensitive areas, where even slight deviations of average global temperatures can cause a real climatic collapse.
A warming began in the 1st century B.C., which lasted (with short intervals) until the early 2nd century A.D. and is known in history as the Roman Climatic Optimum. Average global temperatures and meteorological conditions of the period were very similar to those of today.
The exhaustion of resources and increased aggression of the so-called barbarian tribes, caused by the abrupt cooling in the period between 200 and 700 A.D., resulted in the fall of the Roman Empire (476 A.D.) and the Great Migration of Peoples. The latter lasted until the early 9th century, which was marked by the arrival of a new phase in the history of climate, the Minor Mediaeval Optimum, which ended in the 13th century. The more clement natural and climate conditions and more abundant rainfall favoured the normalization of socioeconomic life of Europe and the gradual settlement of the migrating nomads.
Waves of this warming moved from north-west to south-east, climbing its maximum in Greenland in the 10th century, in Iceland in the 12th, in the Netherlands in the 13th, and reached Eastern Europe in the 14th century. Thus, the 13th century became a “golden age” for Western European agriculture, favourable for the development of the feudal system and for population growth. Chronicles testify that such heat-loving crops as grapes, olives, pomegranates, and figs were cultivated even in the Lower Rhine valley, while England contemplated the expansion of its vineyards. In southern Alsace, trees did not shed leaves even in the winter, and strawberries ripened in December. Despite hot and dry summers which caused crops to fail and provoked famine, scholars consider 800-1200 A.D. to be an essentially good period in terms of economy. The Minor Mediaeval Optimum overlapped Europe’s political map, as it promoted the decentralisation of large feudal states and ushered in a long-lasting epoch of political division.
FROZEN TIME
The early 14th century was marked with an abrupt global cooling, which lasted (with brief intervals of several decades) into the 1860s and is known as the Little Ice Age (LIA). The name for this crucial epoch in mankind’s history was prompted by the notable expansion of glaciers (in particular, the growth of Alpine glaciers in Europe) in the late Middle Ages and Modern Age. The length of this global cooling period is divided into several phases: the conventional LIA, short-lasting warm spells, and the hyper-LIA. The severest climate conditions were registered in 1580-1630 and 1815-60.
Besides expansion of glaciers which was unprecedented in our era, Europe was struck by snowy, cold winters, when the Baltic, Black, and Adriatic seas froze over, while the Mosel, the Thames, the Rhine, the Danube, and occasionally the canals of Venice were icebound for up to four months at a time. Iceland suffered attacks of Atlantic “giants” and had to switch from agriculture to fishing, due to the catastrophic effects of the cooling. Commercial marine communications also considerably deteriorated.
Late frosts in May and snowfalls in June were not uncommon in this period. Together with typically wet summers they often caused crop failures, widespread famines, and epidemics. Europe was particularly badly struck by food shortage in 1314-16, when inclement climate conditions brought about a sharp increase in mortality and soaring bread prices. Famine triggered by nature often led to social unrest, uprisings and revolts, as well as an increase in domestic crime.
Although Black Death (the plague) in 1347-51 which claimed the lives of almost one-third of Europe’s population was not caused exclusively by climatic factors, scholars suppose that long-lasting floods in Eastern China in the 1340s, killing 8 million of the local population, could have triggered this lethal disease, which soon found its way into Europe via the Silk Road and Mediterranean merchants.
A slight warming after the first LIA phase in 1360-90 brought the continent, alongside with milder winters and hot summers, 17 historically recorded droughts.
In German literature the 15th century is labelled “Deserted Villages” (Wüstungen), since, according to various estimates, deadly frosts and severe winters killed from 20% to 60% of the rural population in Central and Northern Europe. Ice formation on the Baltic and the Adriatic enriched the contemporary military art with the practice of ice-field battles. Thus, in November 1495 Muscovy tsar Ivan III tried to storm the Swedish fortress of Vyborg from an icebound bay. Meanwhile, northern merchants adapted to the severe climate, and began to use sledges instead of boats in the winter. Fairs, carnivals, and sports events on ice-covered rivers became part and parcel of Europe’s everyday life during the Little Ice Age.
Economically, the 15th century was one of the most disastrous in history: 40 out of 100 years were afflicted with poor harvests which meant famine. Moreover, during 15 of them crops never ripened at all. The increasing severity of the climate and the aggravation of the struggle for resources were not conducive to continuing feudal disunity, and prompted the political centralisation of European countries. A strong state was necessary to resist natural disasters, and in the Late Middle Ages this took the shape of an absolute monarchy.
Unlike mercenary-minded feudal lords, monarchs, who sought to sustain their renown as protectors of nations, launched a committed struggle against famine, resorting to various measures to overcome the calamity. Those who failed to take famine in hand became scapegoats. Such was the lot of Boris Godunov, the tsar of Muscovy in the early 17th century, whose reign was overshadowed by four successive years of poor harvest, which catalysed a period of popular unrest, known in history as the Muscovite Smuta.
THE GERM OF REVOLUTION
A short span of very hot summers in 1635-39, following the phase of hyper-LIA (1580-1630), brought forth good crops. But it also caused water level in Europe’s rivers to drop, and the contamination of the water by germs of dysentery triggered epidemics and high mortality rates in children.
The first decade of the 1640s proved cooler. Its severe winters were particularly illustrative in terms of the influence of climate on the Old World’s sociopolitical situation. Historians attest that crop failures due to unfavourable weather conditions and soaring wheat prices in 1648-50 aggravated popular unrest in several European countries, which resulted in a wave of revolutions in Ukraine, the Netherlands, France, Naples, Catalonia, Portugal, and England. Of course, all these events cannot be reduced to a common meteorological denominator, and bad harvests and price rises had happened before without any political consequences. Yet at that time climate factors overlapped with a whole set of others (of social, political, national, religious, and economic nature), and ultimately peaked in a surge of revolution.
Paleoclimatologist Emmanuel Le Roy Ladurie unearthed the agrometeorological roots of the Great French Revolution of 1789, the revolution of 1830, and the European Spring of Nations of 1848-49. in his analysis, he treats the effects of climate on crop productivity and grain prices as indicators of popular unrest and triggers of upheavals.
The late 18th century, marked with the so-called Late Maunder Minimum (a cooling period, caused by lower solar activity), was especially memorable in Europe for the cold and hungry 1693-94 in France and 1697 in Scandinavia, Scotland, and Finland. In Finland the population shrank almost by 20%, while in France the loss of life amounted to 1.3 million.
However, a real natural anomaly occurred in 1708-09: the Great Winter, a phenomenon registered once in 500 years. The climatic shock was striking: average European temperature instantly dropped by 3 ºС, and cold Arctic winds swept across the south at 40 km/h, chilling the air to -20 ºС and freezing the rivers. The cold snap destroyed grain crops, olive groves, and vineyards in the south of Europe, sent food prices skyrocketing, and decimated the population. The Great Winter played a role in historical events unfolding at the time in Ukraine. Over several months the arctic cold claimed virtually half of the Swedish army, led by king Karl XII, which eventually determined its defeat, together with Ivan Mazepa’s Ukrainian troops in the battle of Poltava in June 1709.
RAPID WARMING
The reduction of glacier area (and thus the end of the Little Ice Age) caused warm summers and less snowy winters in the second half of the 19th century. The development of communications, international trade, and supply systems helped obliterate the links between the concepts “grain” and “revolt.” Further unrest and revolutionary situations had little to do with agroclimatic oscillations, perhaps the only exception being the severe winter of 1916-17, which dealt a lethal blow to the economically weak Romanov empire.
Global warming (later intensified by the greenhouse effect) set in after 1896, and was more pronounced after 1911, and still continues. For decades, average global temperatures have been rising in arithmetic progression in 1911-20, 1921-30, and 1931-40. That was when humankind first faced a new, unknown kind of warming, unlike the effects of the meteorological oscillations in previous centuries.
1931-50 saw a climate optimum which, however, went largely unnoticed across the world due to the Second World War. There were only three “great winters” during this period, two of which had an immediate effect on history. We mean the severe winters of 1939-40, which obstructed the Soviet invasion of Finland, and 1941-42, where “General Frost” assisted the Red Army against the Wehrmacht.
Global warming became most obvious at the end of the 20th century. In 1988, 1989, and 1990 extreme temperatures were registered during the winter, summer, and throughout the year, while the 1990s became the warmest decade of the century. Early in the 21st century these processes culminated in the hot summers of 2003, 2006, and 2010, whose average temperatures have been the highest in global weather history.
