World leaders have proclaimed a "shared vision" on climate change, but failed to bridge differences between rich and emerging nations on curbing emissions. Concluding a summit in northern Japan, leaders from the G8 and developing countries said "deep cuts" in greenhouse gas emissions were needed. China and other emerging powers declined to endorse specific targets. The three-day summit on Hokkaido island also discussed Zimbabwe, and the global rise in food and energy prices. UN Secretary General Ban Ki-moon had called on the G8 to tackle the "interconnected challenges" of soaring food costs, development, and climate change. On the third and final day of the summit, the G8 and eight developing countries issued a statement calling global warming "one of the great global challenges of our time". But it stopped short of urging numerical targets reducing greenhouse emissions. "Leaders of the world's major economies, both developed and developing, commit to combat climate change in accordance with our common but differentiated responsibilities and respective capabilities," it said. India and China dismissed the rich nations' call for them to halve emissions by 2050. The BBC's Roger Harrabin at the summit says China felt that emerging economies were being implicitly asked to take responsibility for a problem caused mainly so far by the West. 'Criminal cabal' On Tuesday, the G8 - which includes the UK, US, Canada, France, Germany, Italy, Japan and Russia - restated its "vision" of halving harmful emissions by 2050. But Mexico, Brazil, China, India and South Africa challenged developed countries to cut their greenhouse emissions by more than 80% by 2050 Japanese Prime Minister Yasuo Fukuda said the G8 leaders had demonstrated they were serious about tackling climate change. "It is the very first time ever that leaders of the major economies have got down to vigorous discussions on a broad range of climate-change-related issues, and I believe that the leaders have shown strong political will," he said. On food and energy costs, Mr Fukuda said: "The rising food and oil prices add to inflationary pressures, and will therefore raise serious challenges to growth and would have a serious impact on the most vulnerable." During the summit, G8 leaders also called for UN sanctions against Zimbabwe's leadership, because of violence during the controversial re-election of President Robert Mugabe last month. The US and the UK are pressing for a travel ban and assets freeze on Mr Mugabe and his senior allies, and an arms embargo "There should be no safe haven and no hiding place for the criminal cabal that now make up the Mugabe regime," British Prime Minister Gordon Brown said after the summit. But Russian President Dmitry Medvedev said his government could veto the sanctions in a UN vote. Mr Medvedev also said he was "deeply upset" by the missile defence agreement signed on Tuesday by the US and the Czech Republic. The two countries agreed to build a radar station near Prague, as part of America's planned defence shield. Mr Medvedev rejected US assurances that the shield does not threaten Russia, and is meant to counter a threat from Iran. "Russia isn't going to get hysterical but will be studying countermeasures," he said at the summit. Source: BBC