SAPPORO, Japan  - UN Secretary General Ban Ki-moon said Monday that the United States must take the lead in fighting climate change as he opened talks with the world's most powerful leaders. Speaking to AFP on his flight to the summit in Japan, Ban also said he would meet on the sidelines with African leaders in a bid to resolve the political crisis in Zimbabwe. "I hope the US ultimately should take (on) this leadership role. This is what the whole international community expects of the United States," Ban said in an interview with AFP on his plane to a Group of Eight summit in Japan. The United States is the only major industrial nation to shun the Kyoto Protocol as it pushes for more commitment from developing nations such as China and India. "It is not the issue of who should come first and who should come later. But it would be desirable that industrialised countries should lead this by example," Ban said. The UN chief said that he spoke about climate change with Chinese leaders including President Hu Jintao during a visit last week to Beijing. "I know that the Chinese and Indians, they are also committed to this process. I was encouraged by what Chinese leaders have told me," Ban said. The G8 " Britain, Canada, France, Germany, Italy, Japan, Russia and the United States " are set to meet Wednesday in an extended session with leaders of emerging economies including Hu and Indian Prime Minister Manmohan Singh. But few climate negotiators expect decisions on the hard part " agreeing on action to take after the Kyoto Protocol's obligations expire in 2012 " until Bush leaves office in January. Both major candidates to succeed US President George W. Bush have promised tougher action on climate change. A UN-led conference in Bali in December set a goal of reaching a post-Kyoto deal by the end of 2009. "I believe we have technology, we have financing, we have a consensus view that climate change is happening. What is largely lacking is political will," Ban said. "In this world there is tendency that people are looking at their domestic challenges first. They are very much concerned about domestic public opinions," he said. "With limited resources, it may be difficult sometimes for political leaders to look at all these global issues," he said. The last G8 summit in Germany agreed that industrial powers would "consider seriously" at least halving carbon emissions blamed for global warming by 2050. But critics say that the agreement is meaningless without binding targets for what to do in the mid-term to 2020. European Commission chief Jose Manuel Barroso voiced hope that the summit in the mountain resort of Toyako would at least agree on the principle of each G8 nation setting its own mid-term target. "Serious consideration is not enough; we need a decision," Barroso told reporters in Toyako. "It is not likely that during this summit we will achieve a concrete numerical target for a mid-term agreement," he said. But "if we come with a long-term commitment of a 50 percent reduction by 2050 and a principle agreement on mid-term reduction, we can speak of success," he said. Senior US climate negotiator James Connaughton said even if the United States takes strong action, major emerging economies also need to curb emissions. "We believe it is important that ... to achieve deep cuts in emissions requires actions by all of the major economies," Connaughton told reporters. "It is unassailable math."