I think Chuck may be referring to terra preta. Depending on just exactly how large the scale of what the people were doing in the Amazon between 450 BC and 950 AD they could indeed have had an impact on global climate through both deforestation and CO2 production.
Save a life. Adopt a greyhound.
![[Image: JUkLw58.gif]](https://i.imgur.com/JUkLw58.gif)