LONDON, England - February 5, 2011 - Josette Sheeran at the UN's World Food Program puts it well: "If people don't have enough to eat they only have three options: they can revolt, migrate or die."

Shortages of all commodities can cause hardship, but only food and water exact the ultimate price. It is no wonder that spiraling prices are again grabbing the headlines.

A perfect storm of problems has driven food prices even higher than in 2008, according to the UN's Food and Agriculture Organization, which said last week that its main index had hit its highest level in 20 years. The rise to a new peak in January was the seventh monthly increase in a row and there is little prospect of a reversal in the near term.

Catastrophic weather is a key driver, with a major snowstorm in the U.S. dumping 20 inches on some parts of the grain belt. U.S. wheat prices hit a two-and-a-half year high last week.

In Australia, a massive cyclone has added to the misery of the recent floods, threatening the country's important sugar cane crop. The price of sugar has tripled in the last three years.

No wonder countries around the world are hoarding food in a bid to protect their citizens, even though this can only exacerbate the crisis. Indonesia bought 820,000 tons of rice last week while Algeria, with one eye on developments in neighboring Tunisia and nearby Egypt, bought a million tons of wheat.