Rising food prices

Paul Krugman has a post and recent op-ed about an emerging crisis: food inflation. Krugman notes that

[r]ice, the staple food for half the world, gained 2.4 percent to $21.50 per 100 pounds in Chicago, double the price a year ago.

As you'd expect, this is afflicting not just industrialized nations like the United States, but poor countries as well. More important, it is causing big grain exporting countries to hoard their supplies to make sure they cover the needs of their own citizens first, which in turn causes a "run" on grain--the dwindling supply raises prices, which adds to the panic, which causes more hoarding, which raises prices, and so on, in a vicious circle.