It Was Climate Change And Not Spanish Gentlemen That Did For The Aztecs

Drought

Image: criminalatt/ freedigitalphotos.net

As the planet becomes warmer, it’s expected that violent swings in the weather will grow more common, with deeper and more frequent droughts followed by drenching rain. It has been suggested that this is what caused the demise of the Aztec empire early in the 16th century, while it’s commonly-held that invasion by the Spanish was responsible, as such diseases as measles, mumps, smallpox and yellow fever were introduced, and the natives had no immunity.

Hernando Cores arrived in Mexico in 1519 with an army in tow. Then, there were around 25 million people in the country. A century later, a series of epidemics had decimated the population, leaving possibly as few as 1.2 million people. Records speak of a smallpox epidemic in 1519 and 1520 that killed between five and eight million people. Two apocalyptic epidemics followed in 1545 and 1576, killing as many as 17 million people. Richard Nevle of San Jose, California’s Bellarmine College Preparatory School said that around nine percent of the world’s population expired.

Dr. Rodolfo Acuna-Soto, a product of Harvard and now a disease specialist for the National Autonomous University of Mexico in Mexico City, didn’t believe that a deadly disease of European origin could take hold so long after the arrival of the Spanish because the natives would have become immune. Consequently, he spent a dozen years studying the documents left behind by 16th century Spanish priests who worked alongside the Aztecs to record their language, history and culture. These texts tracked key natural events such as droughts, frosts, storms and illness.

The texts included details of the cocoliztli (“pest”) plagues that appeared to be more virulent than smallpox. In 1577, one Franciscan friar wrote, “Nobody had the health or strength to help the diseased or bury the dead.” He told of large ditches being dug in large towns and cities into which priests threw bodies from sunrise to sunset

Francisco Hernandez was the surgeon general of New Spain and also witnessed this epidemic. He detailed an extremely contagious, lethal ailment that killed within days after causing abdominal and chest pains, delirium, great thirst, jaundice, seizures, raging fevers and tremors. He saw blood flowing from people’s ears and noses.

Acuna-Soto said these afflictions didn’t resemble smallpox or any other disease known to Europe at the time, and sounded more like a haemorrhagic fever along the lines of ebola. He attempted to ascertain the cause. He discovered a pattern: plague was preceded by years of severe drought and occurred only in times of heavy rainfall.

To confirm what he had observed, Acuna-Soto worked with Mexican-American dendrochronologists – scientists who examine tree rings to identify changes in climate – using trees in a forest with 450 year-old Douglas fir trees in a far-flung region of central Mexico close to Durango. The tree rings showed that the longest and most severe drought seen in North America in the last 500 years took place in the middle of the 16th century and was succeeded by heavy rainfall in 1545 and 1576 – the time of the cocolitzli outbreaks. This, he affirmed, was “the smoking gun.”

Acuna-Soto now believes the Aztecs were virtually exterminated by an indigenous haemorrhagic fever spread by rodents, with the Spaniards in the clear. Rats decreased in number when drought made food scarce, but the population exploded when rains returned and food and water became plentiful. The relationship is so strong that today, satellite data covering eastern equatorial Africa is routinely screened for Ebola-triggering weather patterns and testing of primates can provide early warning of outbreaks among humans. In such places as California, mosquito abundance has been monitored for over half a century.

Acuna-Soto says that if weather continues to become increasingly erratic, such epidemics will surely return: a virus will emerge for which there is no vaccine or drug treatment. He added, “That’s guaranteed. That’s the big fear of science.” Wild animals often act as reservoirs for microbes capable of causing pathogenic disease in humans. As Charlton Heston intoned at the beginning of Armageddon, it happened before. It will happen again. It’s just a question of when.

About the Author Timothy Chilman

Timothy Chilman used to work in IT. Once, in Sydney, he was turned down for a job because he was “too flamboyant” (“Someone who wears green tartan suspenders to a job interview probably isn’t going to fit in here”). Timothy then became an English teacher. University students in Bangkok complained that he was “too enthusiastic” and company students in Prague complained that he was “too theatrical.”

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