Top industrialized nations need to push forward global talks on climate change and demonstrate their commitment to help poorer nations grapple with rising food prices, the U.N. and World Bank chiefs said Monday.

U.N. Secretary-General Ban Ki-moon and World Bank President Robert Zoellick said rich nations need to strengthen their efforts to meet goals for poverty reduction and education because of instability in the world economy.

"This G-8 summit must bring hope to those without hope, food to those without food," Zoellick told reporters on the sidelines of the Group of Eight industrialized nations in northern Japan. "For globalization to succeed ... it must be both inclusive and sustainable."

The comments came as G-8 leaders met with African heads of state and as aid groups accused wealthy nations of backsliding on a commitment to boost aid to Africa by US$25 billion a year by 2010.

The two also urged leaders to make progress on climate change and energize languishing U.N.-led talks aimed at concluding a new global agreement on global warming by the end of 2009.

G-8 countries are far apart on how to address global warming. European countries are pushing for commitments to cut greenhouse gases by between 25 percent and 40 percent by 2020, but the United States says that's unrealistic.

Instead, the leaders may settle on the goal of cutting emissions in half by 2050, but Ban said that a midterm goal was also needed to prepare financial markets.

"I urge the world leaders present here in ... Toyako to be the catalyst in these collective efforts," he said.

Zoellick and Ban also conceded that the boost in biofuel production had at least in part contributed to the sharp rise in food prices, which has hit Africa and South Asia especially hard.

"There's a range of estimates about the effect, and I think there's no doubt that it does have an effect," Zoellick said.

"That's one reason why I urge at a minimum that the United States and Europe look at some ways of lessening the combination of mandates, subsidies and tariffs," he added.