Leaks of the draft statement for the July 7-9 summit in Japan suggest that rich nations will water down commitments to help Africa and offer little new on cutting greenhouse gas emissions.
Ban, in Tokyo on the first leg of an Asian tour, said that wealthy nations should lead the campaign on the "triple crisis" of climate change, poverty and rising food prices.
"They have the capacity, they have the resources and I hope the leaders will demonstrate their political will," Ban told a news conference in Tokyo. Reports have said that the draft statement of the G8 summit