[Aztlan] Scarlet Macaw trade at Paquime

[E.P. Grondine]

Hi Lennert  -  

>Hi there!
>Tiny question on data. We always see the almost magical and perfect end >date of "AD 1450" in the American Southwest/Mexican Northwest. What does this mean?? ...
(Same can be asked for other American cultures that "ended" just before the arrival of the Europeans, like Moundville in Alabama)

What does it mean? Great question. Possibly a climatic collapse in western North America causing population movements. The climate in North America may not vary in the same manner as that of Eurasia. 

It would be very useful to know if long term climate cycles exist (due to normal long term solar variability?) and how they operate globally. The climate we enjoy at present may not be the one that man faces in the future.

E.P. Grondine
Man and Impact in the Americas