8000 years ago, climate change nearly wiped out South American population, says study

Amazon forest
Amazon forest Reuters

A research by University College of London (UCL) has revealed that humans faced the consequences of climate change almost 8000 years ago, as it caused a dramatic population decline in South America.

Archaeologists examined data from nearly 1,400 sites, including more than 5,000 radiocarbon dates to understand how the population changes over time in South America.

Lead author Philip Riris from UCL Institute of Archaeology said almost 8200 years ago, people who were living across the continent, suddenly abandoned the area. "In our study, we wanted to connect the dots between disparate records that span the Northern Andes, through the Amazon, to the southern tip of Patagonia and all areas in between."

As per the author, the researchers found that thousands of years ago, the continent faced unpredictable levels of rainfall, especially in the tropical regions that might have caused a negative impact on pre-Columbian populations until 6,000 years ago, after which, recovery started.

This recovery appears to correlate with cultural practices surrounding tropical plant management and early crop cultivation, possibly acting as buffers when wild resources were less predictable," said Riris.

In this study, the researchers focused on the transition to the Middle Holocene, a period of time when hunter-gatherer populations were already experimenting with different domestic plants and adopting a new cultural practice that suits both landscape and climate change situation.

When the researchers found that there was a disruption in population, in the study they stated that indigenous people of the South American continent were thriving before and after the middle Holocene.

Manuel Arroyo-Kalin, co-author of the study, said that while the population was declining, the population sizes were unharmed which suggests that early Holocene populations "probably with a social memory of abrupt climate change during the Pleistocene-Holocene transition," might have developed survival strategies.

He mentioned that "Abandonment of certain regions and the need to adapt quickly to new circumstances may have promoted the exploration of alternative strategies and new forms of subsistence, including the early adoption of low scale cultivation of domestic plants."

Arroyo-Kalin also added that while looking at the history of human presence in South America, it should be noted that "the events of the Middle Holocene are a key part of indigenous South Americans' cultural resilience to abrupt and unexpected change."

The researchers studied ancient records of rainfall to collect evidence of exceptional climate events and within a window of 100 years, they compared the Middle Holocene to the prevalent patterns before and after 8200 years ago.

"Normal patterns of rainfall suggest on average an unusually dry or wet year every 16-20 years, while under highly variable conditions this increases to every 5 years or so," said Riris.

However, as per the researchers, their study has given a deep insight into how ancient indigenous South American populations survived during the climate change.

Related topics : Archaeology