Push for new regulations

France has used its position as current head of the G20 to speak out against excessive speculation.

French agriculture minister Bruno Le Maire says high and unstable food prices affect the poor the most. "Nobody can accept to have speculation on the poorest countries in the world, on the people in the world."

The French have been pushing for stricter regulations on commodity speculation in their role as head of the G20. But the negotiations faced stiff opposition -- for the simple reason that many are not convinced that speculators are to blame.

"I don't think there's a very good case at all to be made for much of a speculative impact in our grain markets right now," says economist Scott Irwin at the University of Illinois, adding that most research on the subject does not show that the mere presence of more speculators pushes prices up.

And the evidence that they are adding to volatility is not conclusive.

"There's no smoking gun that clearly points towards the kind of volatility and manipulation problems," says Irwin. "If that's not there, why do you need the new regulations to begin with?"

Irwin adds that new regulations may even push out the speculators the markets need to function smoothly.

He says there is a much simpler explanation for why prices are so high and unpredictable today: supplies of many food commodities are extremely low and demand is extremely high. With such small margins of error, any little bump will send shudders through the market. And the market has taken a lot of bumps in the past year, from drought in Russia to floods in Canada to heat waves in the United States.