Lol.. from the mt St. Helens explosions we know a lot of this is rigged science. Archeologists have a long history of just plain lying and being used by politics, power brokers.
My personal thought is that they get some idea in their head based on their modern ideology and then use their education, tools, and whatever else that is needed to explain something that happened thousands of years ago and tell us we need to stop using plastic bags or whaever. Still doesn’t make them right.
Not rigged- Cahokia went from being the major artisanal and trading center of the Southeast to abandoned about 1300 AD.... It sits on what is arguably some of the richest soil on Earth, in a flood-prone bottomland where corn grows fabulously well, so it would take something like a major drought to cause their agriculture to collapse. It would have to be prolonged because the resources in that area - fish, wetland wildife and flora, deer from the uplands nearby, would take a great deal of time to be consumed- their trading network stretched from the Gulf Coast to the Rockies and East Coast and in the north, Wisconsin, so if one area experienced a poor season or two there would be some way to provide for themselves. They also built granaries against short term crisis, so whatever happened to them was not just losing one year’s crop to a drought.
This isn’t a case where the archeologist is claiming their SUVs caused global climate change...this is a case where a series of events caused normal weather patterns to change in ways the people were unable to adjust to.
Could be their government- under an emperor and noble elite of sorts- was too centralized to deal with the calamity and very likely the people gave up on them when they couldn’t deliver, and revolted or broke up and went their separate ways.
The fits rather well with the Choctaw-Chickasaw origin stories of when they were one people, forced to wander, and separated.
Mt St Helens was tiny.