Friday, May 28, 2021

Pre-Columbus Climate Change May Have Caused Amazon Population Decline

Understand that the Human population in the Americas was a real fraction of 100,000,000 which was particularly concentrated in the Amazon and throughout the tropics thanks to the application of Terra Preta.

Actual collapse began around 1200 AD and was well underway by 1500 AD or three centuries later. The best and likliest explanation is that old world pathogens got an early start, most likely as a result of extensive exploration by the Norsemen.  They could and they did.

Major old world interaction had been limited to modest metal trade for over a thousand years after the fall of the Atlantean world.  plenty of time for isolation to do its job of immunity shift.  Recall just how badly lone islands were hit with the arrival of European sailors.

1200 AD coincides with the era of peak Viking penetration.  these guys could go anywhere and did.  Recall Vinland is really about Duncan on Vancouver island by way of the Northwest passage.  If they could do that, the Mississippi and even the Amazon was merely a trade opportunity.

Pre-Columbus Climate Change May Have Caused Amazon Population Decline

Climate change impacts felt in the Amazon rainforest prior to the arrival of European settlers after 1492 may have meant populations of indigenous people were already in decline before the 'Great Dying', new research has suggested.

Raised fields in the Bolivian Llanos de Moxos region [Credit: Umberto Lombardo]

Scientists studying fossil pollen and charcoal data from across the Amazon say it appears to show that human management of the rainforest may have peaked around 1200 AD, before some sites were abandoned, allowing reforestation of these areas.

The new research, involving University of Reading scientists and published in the journal Science, challenges the prior assumption that the largest population decrease in the Americas - known as the Great Dying - did not start until after European settlers carried new diseases to the continent.

Professor Frank Mayle, a tropical palaeoecology researcher at the University of Reading, and co-author of the study, said: "Our analysis raises the possibility that climate change caused the decline of some Amazonian societies several centuries before the Europeans arrived, especially the more complex societies which may have been too rigid to adapt.

"Although the introduction of European diseases, such as small pox, is still likely to have been the reason for the major population decline subsequently seen in the Americas, the research is a warning of the threat climate change poses to society. Knowledge of how different types of ancient society responded to past climate change may provide valuable clues to understanding the fate of today's diverse societies under 21st century global warming."

The research was led by Professor Mark Bush at Florida Tech, and included a team of international collaborators who are investigating how pre- and post-European people modified and managed Amazonian forests.

Analysis of fossilised pollen and charcoal revealed that many previously deforested lands have been recovering for over 800 years, rather than the 400 years previously supposed, indicating a pre-European population decline. The research team is now looking to assess the drivers and mechanisms of this population drop-off.

Finding signatures of initial forest regrowth following ancient human disturbance is important to ongoing discussions about the impact of Pre-Columbian people on Amazon rainforests and the extent to which modern forests exhibit legacies of past human activity.

This research also has implications for atmospheric and biosphere science. It was previously believed that the indigenous population collapse in Amazonia following European Contact, and subsequent reforestation, led to the sequestration of so much carbon dioxide that global atmospheric CO2 levels decreased markedly, an event known as the 'Orbis Spike'. Yet the team found no evidence that the Orbis Spike was caused by Amazonian reforestation.

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