For the world’s poor, the situation is getting worse.

Surging commodity prices have pushed up global food prices 83% in the past three years, according to the World Bank — putting huge stress on some of the world’s poorest nations. Even as the ministers met, Haiti’s Prime Minister Jacques Edouard Alexis was resigning after a week in which that tiny country’s capital was racked by rioting over higher prices for staples like rice and beans.

Rioting in response to soaring food prices recently has broken out in Egypt, Cameroon, Ivory Coast, Senegal and Ethiopia. In Pakistan and Thailand, army troops have been deployed to deter food theft from fields and warehouses. World Bank President Robert Zoellick warned in a recent speech that 33 countries are at risk of social upheaval because of rising food prices. Those could include Indonesia, Yemen, Ghana, Uzbekistan and the Philippines. In countries where buying food requires half to three-quarters of a poor person’s income, “there is no margin for survival,” he said.