h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Hi, I've been researching the role of climate in the rise and fall of pre Columbian civilisations in the Americas as it is starting to emerge that it played a significant role. (I'm hoping to produce a website on Climate and the Americas sometime.)
I'm really just collating material from a number of sources - archaeology, earth sciences etc. - that haven't been brought together in one place before. Below is what I've come up with for the Andean civilisations of the first millenium. (Early Intermediate, Early Horizon and Late Intermediate) written in two parts. The first is about how climate affected the history of the region. After that section are some more general notes on the individual civilisations that I hope suppliment what Giford wrote above. It's fairly lengthy, but interesting.

I'm always on the lookout for new information, especially about the Amazon, Argentina etc. I've also done the same for Central America and into North America. (Droughts!) Again I'm always interested in new information for those regions too. (I already have a lot on drought and the fall of the Maya.)

It is worth noting that during El Nino events the north Peruvian coastal plains suffer from floods, but further south on the Altiplano, where lake Titicaca is situated, the area is afflicted by severe droughts. The Pacific Ocean wasn't like it is today in this period; between 450AD and 1300AD it was much colder. This produced very major climatic events. El Nino/LaNina events for example that lasted for several years, if not decades. Today they usually last for only 2-3 years. When tying to imagine the floods mentioned below think of the destruction caused to Banda Aceh by the 2004 tsunami. The flooding was on that scale.
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Climate and the Rise and Fall of Andean Civilisations

In Peru, between 100 – 550, the Moche people became increasingly prosperous and established the Mochica state. This was located in the Moche and Lambayeque river valleys, 250 miles (400 km) apart on the coastal plains. (On a map of present day northern Peru - just to the south of its border with Ecuador.) The capitals of each valley were Cerro Blanco and Sipan. In approx. 550 there was a massive deluge. Swollen rivers poured out of the many hill valleys onto the plains, forming a tsunami that covered the plains under 50 feet (approx. 15m) of water and mud. The floodwaters swept crops, fields and buildings away. It is possible that a further series of floods occurred in the following years. (Legend tells of 30 years of flooding followed by 30 years of drought.)

After the flooding the silt that had been carried into the sea then began to be washed back onto the coastal shores. Offshore winds blew sand and dust inland covering the fields with dunes. Then from 563 to 594 there was a prolonged period where precipitation was much reduced, leading to year on year drought, food shortages and famines. The rivers flowing down from the Andean mountains also seem to have shrunk, indicating that the mountain areas that fed the rivers also experienced drought. Ice cores from Andean glaciers showed the reduction in precipitation at this time (drought) was the most severe in the past 1500 years.

The surviving Moche peoples relocated their capital further inland to the head of the Moche valley, establishing a new city of Galindo. In the Lambayeque valley they also abandoned Sipan, again establishing a new city, Pampa Grande, further inland.
Between 636-645 another prolonged drought afflicted the area, covering fields with sand. Archaeologists have uncovered evidence that at this time the Moche began fighting amongst themselves other over resources such as food and land.

In 750 another immense flood struck both their new cities of Pampa Grande and Galindo and the lands surrounding them. The people deserted those cities too dispersing into small settlements. The Moche civilisation had collapsed,.
The Moche people appear to have burnt their temples before leaving; suggesting their faith in their warrior priest rulers had been shattered. In the plain valleys along the coast, the Recuay and Nazca cultures appear to have gone through a period of hiatus and decline, sometime between 550 and 600.

The same sequence of a massive deluge, followed by rivers drying up in the 6th century also happened to the Wari state’s city on the coastal plains. The Wari responded by moving to higher ground in the mountains and so closer to the sources of water. By creating fields on walled terraces, along steep sided valley slopes, and exporting their techniques and know-how to other highland cultures, they created the foundations for an empire that governed most of highland and coastal Peru. It was a method of farming that prevented soil erosion and made the most of available land and water resources.
The Wari built a number of major cities, among them Viracochapampa, located between the Moche and Chao Valleys on the plains, Pikillacta, Cerro Baul and Jincamocco. For around 400 years they and the Tiwanaku empire (below) both ruled huge areas of South America.
Note 1: El Nino/La Nina events are associated with drought or flooding In the southern Americas. During major El Nino events, that typically vary in length between 1-3 years, the high Andean plateau becomes very dry and cold; the more northern Lambayeque valley suffers from massive flash floods and mudslides. During major La Nina events the opposite happens; rains flood the high Andean plateau and highlands, whilst the coastal plains suffer drought.
Their intensity depends upon sea temperatures in the Pacific. El Ninos are followed by a return to cooler La Nina conditions. If both are particularly intense they produce severe droughts followed soon after by major flooding. (EL Nino/La Nina.) Or vice versa if a colder La Nina is followed by a warmer El Nino (La Nina/El Nino.) It’s been described by archaeologist Michael Moseley* as a “convergent catastrophe”*. (* Source: Moseley et. al., The Miraflores El Nino Disaster: Convergent Catastrophes and Prehistoric Agrarian Change in Southern Peru. Andean Past. 2001.)

On the high Andean Plateau (the Altiplano) of what is now Peru and Bolivia, the pre-Inca city state of Tiwanaku was established in around AD 500, close to lake Titicaca. Sediment cores from lake Titicaca and ice cores from the Quelccya glacier reveal that the Altiplano had two wetter than normal periods between 610-650 and 760-1040. These were separated by three dryer than normal periods between 535-665, 855-985 and 1384-1410.

From 1040 onwards the Altiplano was stricken by much reduced precipitation. This gradually lowered the water table and lake levels. The dryer air prevented evening mists forming (these helped prevent frost damage) from water that had evaporated from irrigation channels in the fields. It has been possible to reconstruct lake and precipitation levels from sediment cores taken from the lakebed. By 1100 the lake level had fallen by 36ft. Between 1100-1150 there seems to have been severe drought. The Tiwanaku state’s sophisticated irrigation system finally failed completely at around 1100. Their cities and fields were abandoned. It appears from the remains that its population had just walked away and dispersed. The lower levels of precipitation remained for another 350 years.

The same ‘megadrought’ also brought an end to the Wari empire in the Peruvian highlands. Greatly reduced rainfall and snow melt failed to irrigate the mountainside terraced fields. The Wari were forced to abandoned them. Archaeology reveals that construction work in their capital Pikillacta stopped during the 11th century, then that numerous doorways were sealed up. It had been completely abandoned by 1155. Only the mountain fortress of Cerro Baul remained inhabited, but with a much reduced population.
Note 1: It is possible that the final straw for Tiwanaku was an El Nino. During El Ninos the high Andes become exceptionally arid, but the coastal plains suffer torrential rains and massive floods.
Note 2: The Tiwanaku’s successors were to be the Chimu, down on the coastal plains. The Wari’s successors were to be the Inca in the Peruvian highlands.

At the time of the Altiplano megadrought and also in 1100, down on the Peruvian coastal plain in the Moche valley, two Chimu cities – their capital Chan Chan and the city of Pacatnamu, 100 miles to the north, were almost completely washed away by a massive flood. This also destroyed the complex system of irrigation canals that sustained the Chimu state’s agriculture. The Chimu people piled wood against the remains of their temples and set them alight. Then they abandoned the cities.

These floods were widespread along the coastal plains and significantly damaged the city of the neighbouring Sican State: Chotuna. A Peruvian legend tells that its inhabitants held their ruler, Fempellec, personally responsible for the 30 days of torrential floods and to appease the gods bound him hand and foot and threw him into the sea. The floods were followed by years of famine and disease. It is thought the floods were due to a major El Nino. The Sican established a new capital at Tucume in the Lambayeque Valley.

Archaeological evidence from tributaries of the river Amazon shows that also around 1100 a great disruption again occurred in the Amazonian basin, suggesting a period of mass migration. It is probable that this caused by a cycle of drought, possibly followed by major flooding. (Source: Archaeological evidence for the impact of mega-Nino events on Amazonia during the past two Millennia. B. Meggers 1994.)

Following the decline and collapse of the Tiwanaku and Wari empires another culture, the Chiribaya, began to expand. The Chiribaya lived on the Peruvian coastal plains, but much further south. (On a modern map just north of the border with Chile.) The Chiribaya developed several sizeable settlements on the plains and in the hills rising from them. The most important towns were El Yaral, Chiribaya Alta, Chiribaya Baja and San Geronimo. Many of their field were on high ground to protect them from flooding. But in 1350 a massive El Nino event caused such colossal rains and flooding that the towns were all but destroyed and field and irrigation systems devastated. Archaeologists estimate that 80% of the population died from the flooding and from the starvation that followed.

The more northerly Inca (they called themselves Tawantinsuya)empire was founded in around 1200 by a highland warrior culture taking advantage of the void left by the decline of the Wari. Though famous, the Inca Empire was short lived. It collapsed following the invasion of Spanish forces, led by Francisco Pizarro, in 1533. The Spanish war of conquest against the Inca resulted in the capture of all their mountain strongholds by 1572.
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I produced the below to help provide a context to help people locate cultures and places mentioned in the Climate and the Rise and Fall of Andean Civilisations section above. It compliments what Giford has written.
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The Peoples of Pre Columbian Andes

Overview ~ The Environment
The Andes are a volcanically active region and both the mountains and coastal plains are subject to earthquakes as well as El Nino/La Nina events. This region holds a wide variety of often challenging geographic and climatic regions. It is worth noting that during El Nino events the north Peruvian coastal plains suffer from floods, but further south on the Altiplano, where lake Titicaca is situated, the area is afflicted by severe droughts.

Civilisation began in the Andes and on the Peruvian coastal plains earlier than in Mesoamerica, at around 3,000 BC.
The Moche, Chimu and Sican cities were located on the long strip of arid coastal plains that stretches down the west coast of South America. These lie between the Pacific and the long Andes mountain range. At the northern end of these plains rainfall is 200mm per year, the amount declines the further south you go; the southernmost part of the plains only receive 5mm per year.

Around 50 major river valleys cross these plains and were the focus for settlement. The main building material was adobe; using adobe and cane these civilisations built some of the largest adobe structures the world has ever seen. Pyramids were the main ceremonial structures. The largest fertile area is the Lambayeque Valley to the north, the only sizeable river delta and centre for several important cultures over the centuries. (Today it’s known as the La Libertad district.) From the Lambayeque Valley it was a comparatively short journey through the tropical forests to reach the highlands. It was the ideal location for any trading empire.

The plains of the Lambayeque delta holds about one third of all the coastal land that can be irrigated by river waters. Fogs also helped irrigation. There is evidence that as well as developing raised fields, irrigation systems and canals, the plains peoples also built flood defences. They had good reason to fear floods. The fields supported crops of potato and other root crops, maize, beans and cotton. By the first millennium they had mastered cultivating many varieties of cotton and textiles were a mainstay of the rich economies. Commerce with the highlands and other regions was highly developed. The Peruvian coast is also one of the richest fishing grounds in the world. The peoples of the coastal plains used small reed boats and fishing nets woven from cotton fibres to catch anchovy and other fish that are abundant in the cold offshore waters. The fish were used for more than just food, they also were a rich fertiliser for the fields and another important trade item with the highlands. (Note: El Nino events bring warm water to the coastal waters and kills the nutrients that feed the phytoplankton that the anchovy feed on.) Seaweed and seabird guano were also valuable fertilisers. Shellfish were a useful food and highly prized as decoration, the Spondylus Princepas in particular. The Inca valued Spondylus above gold.

In the Andean mountains around three hundred varieties of potato and other root crops provided staple food items. Alpaca and llama were domesticated for wool, milk, meat and oil and used as pack animals.
The Andes provided two distinct environments that produced civilisations. In the northern highlands the Wari, and later the Inca, developed a system of agriculture by creating terraces of fields on the slopes of steep sided valleys. These were highly practical, as well as using available fertile land the terraces prevented soils being washed away and also helped regulate the flow of water down the slopes. Cultivation at the bottoms of the valleys would have been vulnerable to floods washing away both crops and soil.

Further south, on the high Andean Plateau (the Altiplano) of what is now Peru and Bolivia, the pre-Inca city state of Tiwanaku was established in AD 500, close to lake Titicaca. Agriculture supported a society numbering 170,000 people and Tiwanaku was one of the two great kingdoms that dominated the Peruvian Andes and plains. It developed complex irrigation systems for raised fields spread out over a large area. All the highland civilisations developed stone-masonry to a very high level and mined and worked minerals such as silver, gold, copper etc.

The Coastal Plains Civilisations
The Mochica state was centred on the Moche valley, it also ruled the huge Lambayeque river valley, 240 miles away. The Mochica was a militaristic society, their capital was Cerro Blanco. After just surviving massive flooding, this was followed by a long drought period, 563 to 594, when the rivers also dried up, they relocated further inland and established two more cities, Pampa Grande and Galindo. Between 636-645 another drought afflicted the area, covering fields with sand. In 750 another massive flood struck the cities. The Mochica culture collapsed.

Two other plains cultures from this time were the Nazca and Recuay. The Nazca were located further south in the very arid Pampa region, along the Nazca river between 400-600. The Nazca are best known for the immense figures drawn on the desert plains. Figures so immense that their shape can only be made out from the air. Current thinking by archaeologists is that some of these were drawn in order to mark out underground water systems and outlets. It is unlikely the full meaning of these shapes will ever be understood, as the Nazca left no written records, but the entire landscape was clearly of great symbolic importance to them. The Nazca culture went into decline after 600, eventually becoming absorbed into that of the Wari. Another smaller culture was the Recuay, 400-600. Their historical record ends at around 600. There was a prolonged 32 year drought between 562 – 594.

The Sican state was centred on the Lambayeque valley in north Peru between 900 and 1370. Following disastrous floods, followed by famine and disease, the Sican were conquered by the Chimu.
Following the destruction of their capital city by flooding, in 1100, the Chimu built an empire that almost matched the later Inca empire. The capital was Chan Chan (the largest Peruvian city built before the Spanish conquest). They built large fortifications, as at Saccasihuaman and Paramonga, to defend their borders. The Chimu were the first peoples in S. America to use bronze tools and weapons. The Inca conquered the Chimu in 1470.

Much further south along the plains, the Chiribaya began expanding from 1100 onwards, establishing farms and towns over a sizeable area. In 1350 an extraordinarily large El Nino event occurred, causing such great flooding that it resulted in the deaths of most of the population. (Note: The southernmost coastal plains of Peru are remarkably arid. One extraordinary feature is that after death and burial a natural mummification process occurs. The bodies of the Chiribaya became desiccated. A great many such ‘mummies’ have been recovered, to the fascination of a watching world.)

Recent excavations at another site at Wawakiki, in southern Peru, are revealing another small agricultural culture from this period, this time located on a sea cliff. It seems that by farming higher ground they escaped the effects of flooding.

The Highland Civilisations
The Wari and Incas were centred in the Andean Mountains but at their height also ruled the high Andean plateau. The Tiwanaku were centred on the Altiplano further southwards. The Andean rainy season starts in October and ends in April. The western slopes are semi-arid and only receive rain between January and March. They had ready access to stone for building. The Tiwanaku capital city was on the Bolivian Andean plateau, on the southern shores of Lake Titicaca. They controlled large areas of what are now Bolivia, southern Peru and northern Chile.

Their contemporaries, the Wari governed most of the Peruvian highlands and northern Peru. They shared a religion and artistic tradition with Tiwanaku.
Three Wari cities are Pikillacta, Cerro Baul and Jincamocco. Many of the roads and buildings later credited to the Inca were built by the Wari who by bringing most of Peru under one administration established a unitary state and paved the way for the vast Inca empire. Both these states declined and collapsed during a prolonged drought. The former inhabitants on Tiwanaku became scattered farming communities organised into 12 Kingdoms known as the Aymara. They were soon absorbed by the Incas.

The more northerly Inca (they called themselves Tawantinsuya) empire was founded in around 1200 by a highland warrior culture, taking advantage of the void left by the decline of the Wari. The mountain city of Cuzco was the Inca capital. The more famous Inca city of Machu Picchu was a religious centre and frontier outpost. (Machu Picchu was only rediscovered in 1911.) At its height the Inca Empire ruled an area extending from Equador to Argentina, comprising some 12 million peoples. The Inca emperor was considered to be a living incarnation of their sun god. Though famous, the Inca Empire was short lived. It collapsed following the invasion of Spanish forces, led by Francisco Pizarro, in 1533. The Spanish war of conquest against the Inca resulted in the capture of all their mountain strongholds by 1572.

A Rich Human Pre-History in South America

It’s worth noting that there is a pre-history of civilisations in these regions that extends back 3,500 years. It’s thought that humans have been in the Americas since 12,000 – 18,000 years BC. The earliest human artefacts found so far are from Chile and date to around 11,000 BC. Evidence for agriculture dates to 7,000 BC. By the 15th century AD most of the Americas were quite heavily populated. In total the population of the Americas in pre Colombian times is estimated to have stood at around 40 million people. It may have been higher.

Archaeology in South America is still ‘young’ compared to that of Europe or the Middle East. It is likely that there is still much left to be discovered on the plains, in the jungles and highlands.
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This is a work in progress so it will be re-worked over time. If you want to comment, point out inaccuracies, make suggestions etc. then I'd be grateful if you did. (The part that seems to confuse everyone, myself included at times [though I believe the above to be correct], is who did what and when on the plains; as several states were founded in the same locations on top of former cities.)
I can supply references (sources) if required. I tend to dig into archaeology and science journals.

BBC Horizon did a documentary about the floods and the end of the Moche civilisation. There's a link here to the transcript.
http://www.bbc.co.uk/sn/tvradio/programmes/horizon/peru_trans.shtml

Also from BBC News: http://news.bbc.co.uk/1/hi/sci/tech/4311153.stm