A natural experiment: the Americas

Part IV on agrarian civilisations concludes by considering the possibility of delays and, even, reversals in economic movement, and the possible reasons for any abrupt collapse, although the latter is an unusual event. This chapter begins by recounting the story of the rapid collapse of the Khmer Empire. It considers briefly a series of African empires which appear to have made significant economic advance and then retrogressed. It goes on to indicate the difficulties experienced in Tasmania and some Pacific islands, and the reasons for their difficulties, including size and remoteness. The central part of the chapter is focused on a natural experiment –independent development in the Americas, in which the relevant civilisations independently traced economic and political pathways similar to those in Eurasia. There was a fatal lag, despite an initially rapid but late settlement, because the European intrusion interrupted further movement of native societies.