Pretty simple. Black dots are the food prices, red lines are the riots. In other words, whenever the UN’s food price index, which measures the monthly change in the price of a basket of food commodities, climbs above 210, the conditions ripen for social unrest around the world. CSI doesn’t claim that any breach of 210 immediately leads to riots, obviously; just that the probability that riots will erupt grows much greater. For billions of people around the world, food comprises up to 80% of routine expenses (for rich-world people like you and I, it’s like 15%). When prices jump, people can’t afford anything else; or even food itself. And if you can’t eat—or worse, your family can’t eat—you fight.