Were history’s “golden ages” and “dark ages”, its wars, epidemics and great social upheavals, ultimately due to climate shifts? A new analysis by researchers from the University of Hong Kong find causal links between 14 key, socio-economic, ecological, and demographic variables, and the rise of “large-scale human crisis” events, such as economic downturns, famines, epidemics, social upheavals/rebellions, and war. The strongest linked variable to all these crises events was ‘climate’ The researchers also determined a “crisis threshold” that accurately backwards-predicted the major conflicts and upheavals over the past millennium.