Adverse weather can cause civil unrest

Science : In preindustrial Europe, climate shifts were a statistically significant cause of social disturbance, war, migration, epidemics, famine, and nutritional status, write David Zhang of the University of Hong Kong and colleagues online today in the Proceedings of the National Academy of Sciences. The researchers analyzed socioeconomic, ecological, and demographic data from the years 1500–1800 to try to determine whether cause-and-effect relationships existed between some 14 variables, such as human height, the price of gold, tree-ring width, and temperature. The researchers found that extreme climate shifts influenced human society, primarily through agriculture. Falling crop yield can drive up the price of gold and cause inflation, for example. Whether the research is relevant for the present day remains to be seen. Halvard Buhaug of the Peace Research Institute Oslo points out that trade, technological development, and other processes of modern industrial society make us less sensitive to the climate.