ROME — Resolving the global food crisis could cost as much as $30 billion a year and wealthier nations are doing little to help the developing world face the problem, United Nations officials said Tuesday.

At a UN food summit attended by dozens of world leaders, Jacques Diouf, head of the UN Food and Agriculture Organization, opened the meeting by sharply criticizing wealthy nations who he said were cutting back on agriculture programs for the world's poor and ignoring deforestation — while spending billions on carbon markets, subsidies for farmers and biofuel production.

"The developing countries did in fact forge policies, strategies and programs that — if they had received appropriate funding — would have given us world food security," Diouf, said, adding that international community finally began to mobilize to help after images of food riots and starvation emerged in the media. He said there had been plenty of meetings on the need for anti-hunger programs and agricultural development in poor nations in the last decade but not enough money to make them a reality.

Another major debate that emerged at the conference was the role of biofuels in producing food shortages. The U.S. delegation here maintains that only 2 to 3 percent of food price rises were attributable to the biofuel boom. The UN, however, said the impact was much greater. Biofuel production affects food prices because farmers in many countries have switched from growing crops for food to growing crops for fuel.