Climate change may have had a huge impact on ancient South American civilisations

University of Exeter

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Shira yoshimi maezumi mainTropical palaeoecologist Shira Yoshimi Maezumi extracting a sediment core from Laguna Manguezais in the vicinity of Santarem.

Climate change may have brought huge disruption to ancient South American societies before Europeans arrived in 1492, University of Exeter academics have discovered.

The European colonisation of the continent by Europeans had a devastating impact on local communities. It brought warfare, disease epidemics and mass migration, and caused the demise of 95 per cent of Native Americans.

New interdisciplinary research led by the University of Exeter shows alternations to the climate also brought about widespread changes to how people lived during this period. Recent advances in archaeology, paleoecology and climate science show major ecological and climate change also took place in the centuries before the conquest. This contradicts previous assumptions about how ancient societies in this region operated until they had contact with Europeans.

These preliminary findings will be discussed by scientists at a conference in Cornwall this week. International experts in archaeology, ethnohistory, paleoecology and paleoclimatology will be sharing their data and will work to piece together what happened in South America in the years before 1492.

Increases in the amount of rain may have caused changes to land use and wildfires. Research has shown the Llanos de Moxos savannas in Bolivia were seasonally flooded in about AD 1400. The construction of geoglyphs in Acre in Brazil ended around AD 1400, which suggests people didn’t live there after this time. A similar trend is seen in Central Brazil, where the spread of ‘circular villages’ stops during the same period.

These cultural changes now need to be compared against data collected about the climate, environment and geology, some of which show the beginning of reforestation before the arrival of the Europeans.

José Iriarte, Professor of Archaeology, who is organising the event, said: “Analysing these trends is at the heart of one of the major controversies in American archaeology and climate science. By bringing all these international experts together we have a unique opportunity to shed light on this global issue.

There is some evidence that lowland areas changed from being a net source of carbon dioxide in the atmosphere, used intensively for agriculture, to a net carbon sink. Changes to the climate led to the demise of farmers, and may have caused a “little” Ice Age, where the area had much colder winters.”

The workshop, called Land use and climate changes at the Eve of Conquest in the Neotropics: An interdisciplinary Approach is sponsored by the Pre-Columbian Amazon-Scale Transformations project, funded by the European Research Council. It will be held in Cornwall from 1-4 February.