Catastrophe: An Investigation Into the Origins of the Modern World (29 page)

The city (and the empire) was a religious state to the extent that the rulers no doubt saw their power as divinely derived, and probably identified themselves and the metropolis with the birth of humanity and the beginning of time itself, which is how the later Aztecs saw Teotihuacan. In an uncanny New World equivalent of Christian divine sacrifice theology—evidence, if ever there was, of the global commonality of the human psyche—Teotihuacan was seen, at least by later cultures, as a sort of Mesoamerican Jerusalem where the gods had sacrificed themselves so that humanity might live.

Ancient Mesoamericans believed in a cyclical series of universes. At the end of the life span of each universe it was destroyed, and a new universe then had to be created. The site on which Teotihuacan was built was seen—again, at least by later cultures—as the place where the present universe (the fifth) was born. However, in order for this new universe to be created and life to start again, a divine sacrifice was required.

Thus it was that, according to a legend known from Aztec sources, the gods assembled where Teotihuacan now stands and discussed which of their number would sacrifice himself, become the fifth sun, and so bring light to a reborn world. In a poignant sequence of pain-filled anthropomorphism, the humblest of the gods, Nanahuatzin (literally, “the pusfilled one”), leaped into the flames of creation and became the reborn sun. But the rest of the new universe did not show any signs of materializing, and so the remaining gods had to sacrifice themselves as well.

From their self-sacrifice, the cosmos and the world began to take shape. In the end, almost everything had been formed, from stars to animals, mountains to humans themselves. The establishment of government on earth was also probably seen as having a divine origin. And it was at the very place, Teotihuacan, where the gods had created the universe that there emerged the most powerful government of the Meso-american world—the lords of Teotihuacan, “the wise men, knowers of the occult things.”
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The way in which the religious/ideological basis of society was inextricably interwoven with the economic basis (agriculture) and the political basis (divinely sanctioned government) was the fundamental strength that unified and sustained the metropolis and its power for so many centuries. Yet it was the same close integration of religion, economy, and political ideology that made collapse total when the metropolis and its empire came under unprecedented stress following the worldwide climatic problems of the 530s.

Teotihuacan was simultaneously the Athens, the Rome, and the Jerusalem of the ancient Mesoamerican world. In religious, economic, and political terms, in terms of perceived ancient wisdom, and even in terms of population concentration, the empire’s eggs were all in one basket. Thus, when disaster struck, it struck with a totality and finality that was probably more clear-cut than anywhere else on earth, even at that time of global change and catastrophe.

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ecause there is as yet no tree-ring or other comparable data from central Mexico, archaeologists have no direct way of detecting an individual ancient episode of drought there. There is broad evidence for a general drying of the climate in Mexico in the third to sixth centuries
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., but to find out when any particularly severe crisis-inducing episodes or periods of drought occurred in Mesoamerica, a picture has to be deduced from archaeoclimatic data obtained from adjacent regions, from the world as a whole, and from correlation with potential consequences, in the form of archaeologically detectable events, such as the demise of Teotihuacan.

A detailed analysis of all the available data from the Americas does reveal that a fairly dramatic climatic event occurred across both continents and must therefore almost certainly have affected central Mexico. There is compelling evidence from seven different areas—California, southern Mexico, Colombia, Peru, Brazil, Chile, and Argentina—to suggest that there was severe climatic disruption throughout the Western Hemisphere in the mid-sixth century
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In the late 1960s an American tree-ring specialist, Valmore La Marche of the University of Arizona, collected a substantial number of high-altitude bristlecone pine tree-ring samples from Campito Mountain in California suggesting climatic deterioration—probably colder and drier weather—beginning in 535–536, with a much more serious deterioration in 539. Growth did not then return to normal until the late 550s. Other evidence collected in the 1980s by another American academic, Louis Scuderi of Boston University, from California’s Sierra Nevada Mountains told a similar story, although the data suggested that the episode of climatic deterioration lasted even longer, till around 570.

In Yucatán (southeast Mexico), just five hundred miles east of Teotihuacan, painstaking analysis of lake deposits has revealed evidence of a severe twenty- to fifty-year-long drought that seems to have started in the mid–sixth century. At one lake, Punta Laguna, evidence of this great drought has been provided by water snails and tiny crustaceans called ostracods. The amount of different types of oxygen isotope found in their shells varies according to the climatic conditions prevalent at the time they died. Because oxygen with an isotopic value of 16 evaporated more easily than the heavier oxygen 18, an extended period of dry weather left behind an abnormally high percentage of the latter. The drought can be dated by carrying out radiocarbon dating tests on wood fragments and ostracods, and research carried out by scientists from the University of Florida has revealed that it occurred in the sixth century, was the first such event for almost a thousand years, and was not repeated for another three centuries.
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Similar results were found at a second Yucatán location, Lake Chichancanab, where a massive sixth-century drought was detected by measuring the varying percentages of a particular mineral in the lake sediments.
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In South America, tree-ring data obtained from ancient Fitzroya conifer timbers have revealed that a dramatic cooling of temperature took place in
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. 540. The main evidence is from Chile—but supporting evidence has recently also been obtained from Argentina. The Chilean material—from Lenca, in the south of the country—shows that 540 had the coldest summer of the past 1,600 years.
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In the northern half of South America, there is no tree-ring data going back as far as the sixth century, but there is other evidence of two different kinds, mainly from Peru and Colombia.

Back in 1983 a team of U.S. scientists from Ohio State University’s Institute of Polar Studies climbed Peru’s 18,711-foot-high Quelccaya glacier and succeeded in extracting two ice cores roughly 525 feet long.
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Because there were no helicopters in Peru capable of flying to that height, refrigeration equipment could not be flown in and the ice cores had to be moved out overland. The cores had to be broken up into six thousand samples about two inches long, each of which was then packed in its own individual container and allowed to melt. The Ohio team then had to carry all six thousand samples down from the glacier during a two-day mountain trek, sometimes on 45-degree slopes. The analysis of the samples revealed several episodes in which there had been a decrease in ice accumulation, lower levels of oxygen 18, and an increase in the amount of regionally originating dust—almost certainly evidence of dust storms caused by drought. By far the most intensive and long-lasting episode, and the one that started most abruptly, was a period of drought that appears to have struck in the mid–sixth century and to have lasted around thirty years.

Further confirmation of climatic disaster comes from data on ancient river levels collected from the lower San Jorge Basin in Colombia in the 1970s and 1980s. An analysis by Colombian archaeologists Clemencia Plazas and Anna Falchetti revealed that the mid– to late sixth century was the driest period in the entire 3,300-year-long sequence.
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Similar evidence was discovered in the lower Amazon basin in Brazil and in lakes in the Colombian Andes.
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T
he Colombian and Brazilian evidence—together with the data from Peru, Chile, Argentina, Yucatán, and the United States—shows that there was a severe pan-American mid-sixth-century climatic disaster. The combined evidence strongly suggests that Mexico must also have suffered.

In consequential terms, this is confirmed by the date and nature of the collapse of the great Mexican metropolis of Teotihuacan and its empire. Until recently the depopulation and virtual demise of this vast ancient city was believed to have taken place in the eighth century
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The redating shows that Teotihuacan started to collapse probably around the middle of the sixth century and had disintegrated demographically, economically, and politically by the end of the century.

Teotihuacan has no written history—or at least, none has ever been discovered. Although this extraordinary urban civilization has its own home-grown rudimentary script, it appears to have been relatively unsophisticated, and only parts of it have so far been deciphered.
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So to untangle the sequence of events that led to the collapse of Teotihuacan and its empire, the only data available are those provided by archaeology. But the information yielded by a series of excavations at the site does tell a fascinating story.

In fact, archaeological data from Teotihuacan provide heartrending evidence of different aspects of the end of the metropolis—burned temples, deaths from malnutrition, deserted houses, smashed idols, and murdered members of the city’s elite. Untangling the evidence, it is possible to construct a reasonable model of what actually occurred in the terminal decades of this Mesoamerican Jerusalem.

The climatic disaster that drastically slowed the growth of so many trees in North and South America, dried up rivers in Colombia, and caused dust storms in Peru certainly involved a massive drought. The probable effects of that drought can be seen all too graphically in the archaeological record. In a detailed study, an American anthropologist, Rebecca Storey, of the University of Houston, has analyzed data from more than 150 skeletons unearthed in a small cemetery in an ordinary working-class apartment compound on the southern fringe of the city.
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Her findings reveal that in the years prior to the collapse, people had already begun to die at an earlier age, almost certainly as a result of the great drought and the accompanying massive agricultural failure. Indeed, the death rates for those under twenty-five virtually doubled—68.3 percent of the working-class population were dying before the age of twenty-five, compared to 38.5 percent in more normal times.

The research shows that infectious disease was common in Teotihuacan at all times. However, when the agricultural system failed, nutritional deficiency seems to have substantially reduced the population’s ability to counteract infection. Infection then would have manifested itself in several major ways, often including severe diarrhea and a tremendous reduction in the digestive system’s ability to absorb nutrients. As a result, it was nutrient starvation rather than total unavailability of food that resulted in death.

High death rates in the city (creating demand for new laborers) coupled with economic collapse (due to agricultural failure) in the countryside would have led to substantial migration into the metropolis. But Storey’s research suggests that most of these migrants, with lower immunity to urban disease, died within a few years of their arrival. In the final period (probably the final decades) of Teotihuacan, deaths in the prime migrant age group (fifteen to twenty-four) trebled, from 8.3 percent to 27 percent of total deaths. Another factor in the particularly high level of deaths in this age group must have been the increase in the overall circulation of disease caused by the higher frequency of infection suffered by the migrants.

Because the root cause of the problem was food shortage, it is likely that the Teotihuacano elite would have used their political muscle (and probably at some stage, their military power) to secure sufficient food for themselves. Social divisions would therefore have grown not only in terms of health and wealth, but also in terms of age, intergenerational cultural continuity, parental control, geographic origin (the migrant element), and loyalty to the system.

With so much of the working population dying before the age of twenty-five, the mechanisms of social continuity and control would have broken down. There would have been insufficient numbers of older citizens to pass on cultural traditions to the younger generation. There would also have been large numbers of young orphans who, if they survived, would have passed through their teens with a much-reduced level of adult supervision. And with the rural-to-urban migration referred to earlier, the percentage of people with a lower level of loyalty to the city and its traditions would have increased substantially.

There is also archaeological evidence for change at the top of society. In the terminal period of Teotihuacan, there was a big increase in the amount of military iconography. Wall paintings that had previously been almost exclusively religious in nature were now joined by frescoes that seem to depict members of military sections of the city’s elite. This apparently increased importance of the army developed
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the final collapse of the civilization and probably reflects serious divisions in a ruling class faced with agricultural and commercial collapse as well as increasing social division and unrest. If examples from the history of later centuries in other parts of the world are any guide, then it is more than likely that division within the ruling elite would have led to some sort of military coup, after which strong-arm measures would increasingly have been used to maintain the social and religious status quo.