GHIYATH NAKSHBENDI: "At the end of the day, the most crucial reason for the Arab Spring is basically economic. And so consequently when a citizen cannot have enough money to purchase food and feed his family, definitely that will create a kind of upset with the system."

Professor Nakshbendi says an event like climate change can affect food production in many countries. But in a globally connected economy, even an event in one country can be felt worldwide.

GHIYATH NAKSHBENDI: "Something happening in Thailand is going to have an impact on rice export to other countries."

Cornell University economist Chris Barrett says another problem is that gains in farm production have slowed.

CHRIS BARRETT: "What we are seeing right now is the bitter harvest of very poor investments in agriculture research over really the last twenty years."

Shenngun Fan says the return of high prices in twenty-eleven offers some important lessons. If investment in food production does not increase, he says, then the world will continue to see high prices.

SHENGGEN FAN: "Food price hikes will come more often and more frequent. Second, food prices obviously will remain very high."

He says food supplies are not growing enough to meet the demand of seven billion people. The world is expected to add two billion more by the middle of the century. And people in emerging economies like China are eating more meat, which requires more animal feed. But in twenty-eleven, for the first time, the United States used more maize, or corn, for biofuels than for animal feed.