Upper Mustang province in Nepal, between 400 and 650AD, was part and parcel of the silk road as silk has been found dating from that period. Trade between India and China seems to have flourished and the route across Nepal was probably one of the roads the merchants took. It illustrates the longevity of Nepal as a kingdom with links both north and south and the recipient of new ideas and a trade destination in its own right. See http://phys.org/print378723770.html
The Pueblo people of SW N America had episodes of boom and bust we are told – and various sources can be found for the press release but for convenience see http://phys.org/print378748656.html … It is not known why they abandoned SW Colorado but it seems to fit into a pattern. The paper is published in the journal Science Advances and the link is with other cultural transitions affecting the Pueblo in what is a semi arid region. Climate change is thought to have affected crop yields. Droughts have been pinpointed as the most likely element to cause the shut down of individual Pueblo settlements and movement and re-establishment elsewhere. Increasing aridity caused people to up stakes and move elsewhere – and this seems to have happened even when drought periods were no more than 5 to 10 years in duration. As they lived in communal societies a drop in crop yields affected everyone – and everyone had to move. For example, one of the crisis points was the late 800s and early 900s AD, when in Europe we have evidence of crop failure on three occasions, the last one around 930. This was immediately followed by a climatic upturn – so whatever had been causing the climatic down turns (presumably drops in global temperature as a result of an opaque Sun, haze in the atmosphere) had been washed out of the atmosphere and paved the way for the Medieval Warm Period.
Other crisis periods for the Pueblo were in the 5th and 6th centuries AD and at the end of the MWP in the 13th century. In Europe excess rain and cold weather affected crops, but in the Pueblo country it was drought. In Europe peasants routinely died of starvation as a result of famine and the high price of foodstuffs when it was in short supply, and nothing much was thought about it. It was a fact of life. The Black Death made a dent on the human conscience only because the epidemic struck the elite as much as the poor. In the Pueblo communities everyone lived together in one unit and they probably shared labour – and therefore shared disease when epidemics arose, and shared hunger when droughts struck and withered their crops. The speculation here is that Pueblo people may have temporarily reverted to family units before once again getting together to establish new community groups in the classic Pueblo tradition.