New submitter Stirling Newberry writes "You may have heard of The Great Moderation (PDF), which argues that business cycles have become less volatile over time, and the Green Revolution, a set of initiatives that led to increased global food production. These, it has been argued, have led to a marked decrease in war across the world. But not so fast, says a study in Science. It may well be that periods of war, past and present, can be linked to changes in climate: 'The most direct way in which extreme climate shifts influence human society is through agriculture, Zhang says; a falling supply of crops will drive up the price of gold and cause inflation. Similarly, epidemics can be exacerbated by famine. And when people are miserable, they are likely to become angry with their governments and each other, resulting in war. But golden ages rise out of these dark periods, the team argues. For instance, a 100-year cold period beginning in 1560 caused shortened crop growing seasons. The researchers found a causal linkage with a decline in average human height by nearly an inch during this period, and the century was rife with disease and conflict. But the world began to warm in 1650; when Charles II was crowned king of England in 1660, the coronation sparked the Enlightenment era in Europe.'"