This was not a sudden crisis. It may be only this spring that food prices have started sparking riots on the streets of Haiti and Egypt, not to mention rice rationing at Wal-Mart's cash-and-carry stores, but food prices have been rising since 2000. The rises accelerated in 2006, when global cereal stocks dropped to levels not seen since the early 1980s. And although the factors driving them are many and various, a good few of them look likely to persist for years to come. (Editorial)