According to a new study released by researchers at the New England Complex Systems Institute in Cambridge, high food prices play a direct role in the rise of political instability in North Africa and the Middle East. As shown in the graph above, when the UN food price index rises above a certain level, the number of riots increases around the world. The study mentions two factors that are leading to higher food prices: investor speculation in the commodities market, and the use of corn for the production of ethanol in the US.