Friday, 6 January 2012

Maya Civilisation


Mayan ruins

The Mayan ruins of Tikal are hidden deep in the rainforests of Guatemala. From the air only a handful of temples and palaces peek through the canopy. The stone carvings are weather-beaten. Huge plazas are covered in moss and giant reservoirs are engulfed by jungle. The only inhabitants are wild animals and birds.
But 1,200 years ago, Tikal was one of the major cities of the vast and magnificent Maya civilisation that stretched across much of what is now southern Mexico, Belize and Guatemala. Tikal was home to perhaps 100,000 people. Thatched farmsteads and fields would have stretched as far as the eye could see.
Their civilisation was so stable and established, they even had a word for a 400-year time period.
The Maya thrived for nearly 2,000 years. Without the use of the cartwheel or metal tools, they built massive stone structures. They were accomplished scientists. They tracked a solar year of 365 days and one of the few surviving ancient Maya books contains tables of eclipses. From observatories, like the one at Chichen Itza, they tracked the progress of the war star, Venus.
They developed their own mathematics, using a base number of 20, and had a concept of zero. They also had their own system of writing. Their civilisation was so stable and established, they even had a word for a 400-year time period.
Mayan society was vibrant, but it could also be brutal. It was strictly hierarchical and deeply spiritual. Humans were sacrificed to appease the gods. The elite also tortured themselves - male Maya rulers perforated the foreskins of their penises and the women their tongues, apparently in the hope of providing nourishment for the gods who required human blood.
In the ninth century, the Maya world was turned upside down. Many of the great centres like Tikal were deserted. The sacred temples and palaces briefly became home to a few squatters, who left household rubbish in the once pristine buildings. When they too left, Tikal was abandoned forever, and the Mayan civilisation never recovered. Only a fraction of the Maya people survived to face the Spanish conquistadors in the 16th century.
For decades, archaeologists have been searching for an explanation of the Maya collapse. Many theories have been put forward, ranging from warfare and invasion to migration, disease and over-farming. Many think the truth may lie with a combination of these and other factors.
But none of the conventional theories were good enough for Dick Gill. He believed that what had devastated the Maya was drought. However, drought as the only explanation of the Maya collapse was highly controversial.
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Massive drought

Drought destroyed the Mayan civilisationReconstruction of Mayan drought devastation  ©Dick Gill was a most unusual person to put forward a bold new theory explaining the collapse of Mayan civilisation. When he started his hunt for clues, he was actually a banker.
His love affair with the Maya started back in 1968 when he visited Chichen Itza in Southern Mexico while on holiday. The Mayan ruins, he says, really touched him. He resolved to solve the riddle of the Maya collapse - but he still had a banking career to pursue.
In the early 1980s, fate stepped in with a Texas banking crisis. The family bank collapsed, and Gill was suddenly out of work and free to follow his dream. He went to college to study anthropology and archaeology.
His realisation of what might have caused the Maya collapse came in a brainwave - it was an explanation that didn't come from books and study, but directly from his own childhood. Gill remembered the devastating droughts in Texas in the 1950s, when farmland was parched and fires raged. The hot, sunny days seemed interminable, and he was left with an emotional understanding of the power of drought.
His work led him to a dramatic conclusion - that the Maya civilisation consisted of millions of people who had died very suddenly.
He felt sure the Maya had faced a huge drought, but he had no evidence to back up his theory - so he set out to search for clues. One of the first people he turned to was archaeologist Dr Fred Valdez.
Valdez, from the University of Texas, worked deep in the jungles of Belize. He counted Maya farmsteads in order to estimate the likely total population. Fragments of pottery told him when the area was occupied and his work led him to a dramatic conclusion - that the Maya civilisation consisted of millions of people who had died very suddenly. Gill knew few factors could account for this - but one of them was drought.
In Gill's eyes, this strengthened his theory, but he still needed direct evidence. It was time to trawl the archives. National records held in Mexico City revealed that, at the start of the 20th century, a drought in the Maya region had lasted three years. Here was evidence that drought could, in fact, occur in this region.
He then stumbled upon older, colonial records from the Spanish authorities in the Yucatan province of Mexico, telling of repeated drought. 'I found this plea for help', he says. 'The crops had been very bad in the year 1795 - they were running out of grain and they were afraid that the terrible death they had seen so often in the past was going to repeat itself again, so they asked for help.'
Gill now had proof of devastating droughts in the past, but not in the key ninth century. Then he discovered an extraordinary coincidence. He'd studied hundreds of papers on meteorology before he stumbled on one entitled 'Dendrochronology, mass balance and glacier front fluctuations in northern Sweden'.
It had been extremely cold in northern Europe at just the time of the Maya collapse, but what could possibly be the link? Gill went back to the meteorological records, and found that one of the high pressure systems in the north Atlantic had moved towards Central America at the start of the 20th century. This was a time of both drought in the Maya areas and extreme cold in northern Europe.
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Conclusive proof

Mayan reservoirReconstruction of a Mayan reservoir in its prime  ©Though the circumstantial evidence was growing stronger, Gill still didn't have direct proof of devastating drought in the Maya areas in the ninth century. He finally got that evidence when a team from the University of Florida visited Lake Chichancanab in Mexico's Yucatan region.
The scientists discovered that the ninth century had been the driest time in the region for 7,000 years.
The team was interested in past climates and measured them by taking cores of mud from the bottom of the lake. The mud had built up over thousands of years - the deeper the mud, the older the shells and seeds it contained.
Back at their labs in Gainesville, they looked at tiny shells from each part of the core, and in particular the two types of oxygen locked in them - heavy and light.
The surfaces of shells from times of high rainfall are dominated by light oxygen. More of the heavy oxygen means the water in the lake was evaporating at that time. A core from the ninth century showed an exceptional surge of heavy oxygen, indicating it was the driest time in the region for 7,000 years.
Here at last was the clinching evidence Gill had been searching for - exceptional drought at the time of the Maya collapse. His quest was over, but it had been an emotional journey of discovery.
'There's a certain satisfaction that I have finally understood what happened to the Maya, but as a human being it's awful to think about what happened', he says.

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