Abstract
Doubtlessly the next decades will be amongst the most challenging periods in the history of humankind. In this they bear a tragic component: for the first time humanity as a whole will be challenged by problems induced by humans themselves, by the Anthropocene and its major alterations in the Earth system, one component being global warming. In the light of this challenge also archaeology, anthropology, and the historical sciences have addressed the topic of climate impacts on human history. This has particularly been the case for one of the most important quantum leaps in the history of humankind, the emergence and the dispersal of farming. Numerous studies have been undertaken, sometimes with data sets of considerable detail. But while earlier studies had proposed almost exclusive external mechanisms in that climate might have triggered and shaped the dispersal of farming, newer studies have adopted a much more nuanced approach. When we look at case studies with high-resolution data sets, simplistic scenarios become inapplicable. Any historic process must nowadays be understood as a result of complex positive and negative feedbacks, and it appears that from early farming societies onward endogenous social dynamics had played considerable and hitherto often overlooked roles. This is of course not to say that each decline or collapse in the course of human history was induced solely by internal processes, but these factors need to be addressed. Therefore, we have focused on an important social factor, namely social cohesion. Our two case studies, being seven thousand years apart, suggest that early farmers and modern industrial societies underwent fluctuations in social dynamics that were and are inherent. The degree of social cohesion might determine the effectiveness with which societies were and will be able to cope with external stress factors. So, for the future, ameliorating the possibly grave challenges of global change may greatly depend on the social cohesion of human societies, on local, regional, and global scales.
