The limitation of desert, forcing to joint efforts with growing population is an interesting one. I had not considered the role tbe desert(s) play(s) in this.Ecurb wrote: ↑September 29th, 2020, 12:14 pm The archaeological record shows two developments that occurred at about the same time (the time-line cannot be differentiated by the record). These are the development of organized warfare, and that of major irrigation projects. The development of "civilization" (if not governmemt) appears to have occurred in river valleys surrounded by deserts -- the Nile, the Tigris-Euphraties- the Indus - the Yangtze -- central Mexico. As farming developed and the population grew, people were confined by the environment. The record shows the development of irrigation projects, which were large enough that they must have resulted from large-scale cooperative efforts, and must have been regulated by some sort of "government".
I was looking to verify/falsify this thought by means of geological surveys, because I have read that the sahara, for example, was once a lush jungle. I could not find good sources on the state of the environment throughout the milennia though. Does anyone have a good source for that?