A third period that shows the impact of climate change on conflict has to do with cooling conditions and the onset of the Little Ice Age (LIA). Scholars differ exactly on how long the LIA lasted. Some believe it started as early as 1000 in some northern regions. Historian Brian Fagan believes the LIA lasted from 1300 to 1850 (Fagan 2008). Agriculture records from the period show that vineyards gradually disappeared from England, and the cultivation of oranges in north China was no longer possible. The movement of crop zones suggests patterns of climate change.
As growing seasons became shorter in the Little Ice Age, people moved from colder areas to warmer ones. Famine spread, especially during a cold period around 1600, where agriculture production was at a minimum in Scotland.
When crops failed again in 1612 because of the weather, King James VI kicked many Irish out of Ulster, which was slightly less affected by the savage weather, and allowed Scottish farmers to move in. By the end of the century, 100,000 Scots had established themselves, setting the stage for the religious conflict between Protestant and Catholic that has dogged the region for the past three hundred years.
(Linden 2006: 82)
The same scene played out in the Baltic area, and many in Estonia starved to death. The cold climate especially affected Sweden by increasing death and migration, both of which greatly weakened the state. During the Great Northern War, which occurred in an extremely cold period (1700-1721), Sweden lost most of its empire to Denmark, Poland, and Russia. The socio-political impact of the Little Ice Age followed Europeans to the New World.
Climate change can produce short-term, volatile conditions. The Little Ice Age led to periods of climate extremes that had a substantial impact on conflict. Sudden and violent summer storms in 1588 doomed the Spanish Armada. The year 1812 was one of the cruelest Russian winters, and helped decimate Napoleon's army. The Little Ice Age played a significant role in these two events that were of consequence to European history: "The Little Age represented a minor perturbation of climate, it seemed to have outsized effects on European history" (Linden 2006, 28).
The Little Ice Age was not singular in its impact. Southern Europe no doubt benefited while Northern Europe suffered. Since the period extended for many hundreds of years, the impacts also fluctuated over time with the intensity of the cold.
Those who argue against a single event cite the fact that the LIA began at different times in different parts of Europe. The first frigid breath hit Iceland early in the thirteenth century, while Italy escaped the brunt until the fifteenth century.
(Linden 2006, 172)
Two cases focus on extremes during the Little Ice Age. The first case concerns the collapse of precipitation patterns in transition zones and the disappearance of the Anasazi. The second case focuses on shorter-term periods of extreme cold and the year without summer.
Hot War: the Anasazi ecotone
Climate change in a single period often produces very different outcomes for peoples and societies in the Equatorial Tension Belt compared to the Polar Tension Belt. Hot periods benefit areas of cooler climate, in that they become more habitable. Cold periods benefit areas of warmer climate, as they become cooler and often wetter. For transitional areas or niche ecotones, the warming changes in cooler areas will cause immigration that may lead to conflict. For warming changes in warmer zones, the result may be emigration. In the past, migrations were to nearby areas, so there was not a lot of movement from the Equatorial Tension Belt to the Polar Tension Belt.
Migrations are often trickles of people over a long period rather than a sudden exodus. Migrations, however, look different regarding where the people come from versus where they are going. Emigration is usually quite concentrated, so that continuing departures begin to sap the ability of the community to survive.
Where the people go is fairly diffuse, and could be in any direction or distance. If migration is sufficiently slow, the migrants mix with local populations and slowly, over time, "disappear" into a different demographic group.
The first people in the Southwest part of the United States were nomadic people who arrived around 10,000 bc . They were part of the Clovis culture, and became settled around 900 bc . The Anasazi were a Native American people descended from this original group.
The Anasazi lived in the Four Corners region (where four US states come together: Colorado, Arizona, New Mexico, and Utah) around 100 bc . The area is extremely dry, but the Anasazi perfected a system of subsistence that built along the narrow canyons and ribbons of water. The habitat provided shelter, safety, and housing.
The Anasazi evolved in five periods. They moved to the area around the year 100 and evolved from hunter-gatherers to agriculturists, settling and becoming sedentary around 450 (Breternitz and Smith 1975: 36.). There was an emphasis on relatively simple technologies during that time, which was known as known as the Basket Maker Period.
A period of further refinement followed, called the Modified Basket Maker Period, which lasted until 750 (see Table 2.3). One change was the development of new weaponry for hunting game and fighting with other people. Over this period, the Anasazi replaced the atlatl with more advanced tools. The atlatl was a wooden device for propelling a spear, and an adaptation from the earlier and larger Clovis point weapons used by mammoth hunters. Later, the development of bow and arrow technology proved to be a much more useful weapon in the group's arsenal, and permitted hunting of a larger variety of game. This led to food surpluses, but the limited supply of game was quickly exhausted.
Simple technological advances built over time, and slowly the rural lifestyle became urban. This led to the Developmental Pueblo Period, which capped a long process of evolution. Anasazi populations reached their maximum around the year 1000, largely through more efficient farming techniques. The Pueblo Period marked the culmination of this urban lifestyle.
Urbanization brought its own problems. The culmination of the Pueblo Period also meant that hunters needed to travel farther and farther from the city for game. Michael Allen and Robert Stevens compare the urbanization of the Anasazi with modern problems that result from exceeding tipping points in sustainability:
Modified Basket Maker
With their more settled lifestyle came the need for more permanent housing for the slowly increasing population. Although the change was not immediately evident, these cultural adaptations gradually changed the relationship between the Anasazi and their land. The ultimate impact of disturbing the delicate balance between the use and abuse of the land took several hundred years to manifest fully.
(Allen and Steven 1996: 156)
This gradual process of technology improvement was too successful and, over time, Anasazi population exceeded the region's carrying capacity. This was the Decline, or the fifth period, in the history of the Anaszi. The Anasazi subsequently disappeared. Apache and Navaho tribes followed as the next residents in the region. Spanish invasions pushed them out of their own homes.
The Anasazi survived a long-term drought and many smaller ones. Why were they unable to cope with this drought? Climate change and conflict, along with a multitude of intervening variables, is a likely explanation. The drought was widespread. Similar to their Anasazi cousins, the Hohokam (to the southwest) and the Mogollon (to the south) tribes also declined after 1300. These neighbors might not have been in a welcoming mood for emigrants.
The special climate ecotone the Ansazi exploited was a thin slice within a larger inhospitable zone of existence. Even small shifts in climate can upset such a delicate social calibration. Chaco was a key city of the Anasazi for cultural, economic, and political reasons. Chaco linked out to the rural areas through a radiating road system. It was a key point for importing of resources, including great timbers that built the houses of the city.
Chaco was built on a fragile foundation. Chaco's history mirrored that of the Mayans. The population grew during a favorable climate, but collapsed when the climate turned drier and the carrying capacity fell. "Chaco had developed rapidly during a long period of relatively plentiful rainfall by San Juan standards. . . . Agricultural productivity withered, water supplies slowly evaporated" (Fagan 2008: 134-5).
A number of researchers believe the Anasazi were victims of climate change. Some precipitation changes were incremental but some were wholesale. Other changes in rainfall were more dramatic, and even seasonal rains failed:
Careful scrutiny of tree-ring records seemed to establish that in the late 1200s a prolonged dry spell called the Great Drought drove these people, the ancestors of today's pueblo Indians, to abandon their magnificent stone villages at Mesa Verde and elsewhere on the Colorado Plateau, never to return again.
The drought is responsible overall for the fate of the Anasazi, but other factors made the precarious climate situation more complex and deadly. Climate change set off a chain reaction:
[The] so-called Great Drought . . . simply was not bad enough to be the deciding factor in the sudden evacuation, in which tens of thousands of Anasazi . . . moved to the Hopi mesas in northeastern Arizona, to the Zuni lands in western New Mexico and to dozens of adobe villages in the watershed of the Rio Grande.
Even more telling is evidence that the Anasazi had weathered many severe droughts in the past (just as the Neanderthals had weathered several Ice Ages). Why did the drought in the late 13th century cause an entire population to abandon the settlements they had worked so hard to build?
Archeological evidence shows that in this period, perhaps as a reaction to drier weather, people in the Mesa Verde area began building dams and canals to trap water and divert it to terraced fields. How do we link the record to the theory? "Correlating these tree data (dendrochronology) with information on productivity of various soil types, modern crop yields, and detailed geography, Adler concludes that enough corn could have been grown during the drought to support the population" (Johnson 1996: c-1). Archeologists believed the Anasazi suffered from long-term issues of malnutrition, shorter life spans, and increased infant mortality, but there is little evidence of any short-term catastrophe.
Some climatological evidence, based on tree-ring and pollen studies, suggests that Anasazi farmers may have kept moving to higher, moister grounds in reaction to the drying trend. Nevertheless, this strategy was flawed: lower elevations were too dry for farming, and higher ones too cold (Van West 1994).
The drought was important, but not sufficient to explain the Anasazi collapse. "The peculiar character of the abandonment is its completeness, its rapidity. This suggests that some kind of 'pull' was operating as well - or an ideology favoring migration" (Van West 1994). There were numerous religious symbols found on rocks or pottery, and a distribution of ceremonial structures, suggesting that the Anasazi may have left their homeland for a new religion, perhaps to the south.
Recent climate studies suggest a disruption of rainfall patterns in a way that perhaps disillusioned Anasazi with their old religion. Suddenly, the customary pattern of heavy snows in the winter followed by summer monsoons became unpredictable. Even if there was not a great drought, moisture may have been coming at the wrong times. The summer rains, so necessary to keep the spring crops from dying, were no longer reliable. The rain dances no longer worked.
There are also links to the Mayans that helped shaped Anasazi culture. There were Meso-American influences on culture and architecture (great houses), and technologies for agriculture, ceramics, and weaving came from the south. Some researchers surmise that the introduction of teeth-chiseling and possibly cannibalism came from the Mayans. Perhaps the Anasazi knew the fate of the Mayans and their apocalyptic collapse.
The declining resources led to three stages of conflict. First, the Anasazi cities, like Chaco and Mesa Verde, fought against one another, just as the Mayan cities, like Tikal, Tamarindito, Arroyo de Piedra, and Dos Pilas, had done.
Second, as the city-states gradually weakened under the weight of climate and conflict, conflict would have focused on livelihoods. Once livelihoods become unsustainable, societies slowly evaporate. The third phase was desperation. The Anasazi may have turned to a new food source: each other. In New Mexico, the remains of 12 Anasazi were found; seven of them seemed to have been eaten (Fagan 1994).
Periods of rapid climate change may produce more extreme events. Some extreme events have geological causes that can alter trends of climate, especially in the short term. Along with the changing climate, there may be weather or external natural events, such as colliding asteroids, that may produce extraordinary spells of flood, drought, heat or cold.
Extreme events are the link between the short and the long term in climate change and conflict cases. They compress climate patterns and trends into shorter, destructive episodes. In pre-modern times, these extreme events could and did play major roles in history.
There were sharp extremes in temperature during the Little Ice Age. The period actually had two temperature low points, one during the late 1400s and early 1500s, and another during the late 1700s and early 1800s. This latter extreme cold period, coupled with a catastrophic geologic event in 1815, produced the year without summer.
Against this longer-term climate trend was a volcanic event. In April 1815, Mount Tambora on the Indonesian island of Sumbawa threw a massive amount of volcanic dust into the atmosphere, one of the largest volcanic explosions in modern times. When it exploded in 1815, Tambora sent more dust into the upper atmosphere than "any volcano between 1600 and the present. Tambora would be the most explosive eruption in the last 10,000 years" (Stommel and Stommel 1983: 3). The eruptions continued from April until July. About 70,000 people died immediately. On nearby Subawa Island, there were 12,000 residents before the eruption; only 26 people survived.
The Tambora eruption was one of the most cataclysmic natural events in recent history. Tambora ejected 100 cubic kilometers of material into the atmosphere. In comparison, the eruption at Krakatoa in 1883 ejected ten cubic kilometers, while Vesuvius in ad 79 and Mount Saint Helens in 1980 ejected one cubic kilometer each. Due to the debris in the air, points within 200 miles of the Tambora Volcano were in total darkness for three days following the eruption (Stommel and Stommel 1983: 10).
Between 1450 and 1850 global temperatures were between 1.0 and 2.0 Centigrade cooler than they are now. Within that, the settlers were living in what some climatologists say was a cooling trend between 1809 and 1820. And in the middle of that came the 1815 eruption of Tambora.
The eruption may have been part of a series of global geological events. Mt Tambora's outburst followed other major eruptions: of La Soufrière Volcano on Guadeloupe Island in the Caribbean (1812), and of the Philippine Mayon Volcano on the island of Luzon (1814).
Tambora's dust spread worldwide and blocked the sun's rays, cooling the climate. In Canada and New England, heavy snow in May killed newly planted crops. The cold weather did not end until the summer of 1817, and in 1816 most of the crops and livestock were lost. Ice formed in rivers and lakes as far south as Pennsylvania, well into the summer.
In June 1816, temperatures in New Haven, Connecticut were 7° Fahrenheit below average, and led to the coldest June on record. Killing frosts occurred in New England in June, July, and August. Corn was, at the time, the staple crop in New England, and three-quarters of it was lost. The cold was only part of the problem. There was also a prolonged drought in other parts of the country in 1816, notably in the south, from New York to Georgia.
One account from a diary kept by a resident of Alleghany County, New York, describes the conditions that began with snow in June and kept up through the summer of 1816:
To the surprise of everybody, August was the worst of all. Almost everything green in this country and Europe was blasted with frost. Snow fell at Barnet, 30 miles from London, England, on August 30th. Newspapers received from England stated that 1816 would be remembered by the existing generations as the year in which there was no summer. Very little corn ripened in New England. There was great privation, and thousands of persons would have perished in the country had it not been for the abundance of fish and wild game.
Several American scholars point to this cold period as a major impetus for a large population migration from the state of New York and from New England to the Midwest during this time. What enabled the migration process was the subsequent opening of parts of the Erie Canal in 1819 and its completion in 1826.
The consequences of the year without summer were important. In Canada, the province of Quebec banned the export of staple crops such as wheat, flour, beans, peas, and grains. Prince Edward Island, New Brunswick, and Nova Scotia followed suit, and halted exports of grain and other foodstuffs. Newfoundland turned away a boat full of immigrants. As in Canada, agricultural trade slowly stopped in Europe. "At the height of the famine, Swiss cantons sealed themselves off, prohibiting the export of grain to one another" (Stommel and Stommel 1983: 47).
"The cold summer of 1816 set many records in Europe" (Stommel and Stommel 1983: 46), and led to disease. Most people were still largely involved in agricultural self-subsistence. Cold weather led to lower agricultural production, and human nutrition levels fell dramatically. "Ireland's famine led to a typhus epidemic that in the years 1815 to 1817 afflicted 1,500,000 people and killed 65,000. The typhus spread all over Europe" (Stommel and Stommel 1983: 44).
The eruption of Mt Tambora had great consequences for the world's climate, and this was especially true in Europe and North America. Contributing to the crisis were the social issues of the times. The eruption followed the Napoleonic Wars, that had left Europeans destitute:
Two years after the battle at Waterloo much of Europe was facing famine. The aftermath of protracted conflict was marked by columns of refugees, some heading east into Russia (where food was still plentiful), whereas others moved west-ward to escape to the Americas by ship. In Germany and Switzerland people were eating cats, rats, grass and straw. In Italy, beggars flocked to cities, whereas in England demobilized soldiers and unemployed farmhands lined up to join food-for-work activities. Hundreds of thousands of Europeans died from the combined effects of typhus, exposure and starvation.
(Webb 2002: 2092S)
Examining trends in staple crop yields and prices shows the economic impact of extreme cold climate in the year without summer. "Wheat yields in England, Ireland and France were at least 75% lower than the recent norm" (Webb 2002: 2092S). Patrick Webb tied crop prices to yields:
Wholesale wheat and rye prices (set at 100 for 1815), roughly doubled in 1817 in many countries. The worst affected area was southern Germany, where prices increased fourfold within 12 mo[nths], the peak occurring from May through July of 1817. Such rapid and extreme instability in the price of basic foods resulted in a consumption crisis manifest from Scotland to Sicily.
(Webb 2002: 2092S)
Mortality rates rose significantly throughout Europe. Deaths were most concentrated in central Europe around Southern Germany and Switzerland, where there was widespread famine. The food crisis of 1817 threatened the stability of European countries, which responded with emergency provisions of food supplies for some of the starving people. This primitive food program could not stem the problem, and food riots erupted in England and France. An uneasy populace confronted the conservative monarchies that survived Napoleon, and there remained radical pockets, still inspired by the French experience. Revolutionary governments came to power in Spain and in Naples, Italy. A restored French monarchy invaded, and overthrew Spanish revolutionaries.
In the aftermath of Napoleon's defeat in 1815, France was a battered country with few reserves to fall back on. The struggle between the royalists and liberals provided the structural divisions in the country, and the cold summer provided a trigger for violence. Riots broke out in Poitier when the government imposed a wheat tax. Farmers bringing their crops to market required armed protection to prevent angry mobs from stealing their wares. Al Gore discussed the year without summer, and the conflict consequences, in his book Earth in the Balance, saying: "As fears of revolution mounted in several countries, military force was used to control the growing crowds demanding food. An unprecedented wave of arson began to strike in almost every country" (Gore 2002: 56).
The impacts of the year without summer show two differing outcomes in Europe and North America. In Europe, the structural situation was dire. Napoleon's defeat at Waterloo in 1815 was the culmination of a long period of continent-wide warfare in Europe. In the aftermath of the war, basic livelihoods suffered and revolutionary fervor competed with a royalist resurgence. Population density was high and arable lands already claimed, leaving no pressure valves for populations put under temperature-induced duress. The result was social upheaval, riots, and disease.
In North America, the War of 1812, a conflict related to the Napoleonic Wars, was ending. Population densities were still rather low in the United States. The central government remained relatively weak, and the White House had recently burned. Unlike in Europe, however, there were ample lands to the west in the United States that provided migrants with opportunities, and the beginning of the Erie Canal in 1817 offered a means for them to take their chance. The pressure valve there worked quite well.
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