Top economies and developing nations joined hands in the fight against climate change Wednesday, vowing support for UN-led global warming talks at the conclusion of a sprawling summit that pledged more aid for Africa and condemned Zimbabwe's disputed presidential vote. On the final day of a three-day Group of Eight summit, a US-sponsored group of 16 countries and the European Union said they would set medium- and long-term goals to reduce greenhouse gases to save the planet from the worst effects of global warming, but they did not agree on specific targets. The accord came at the end of a summit that had been dominated by concerns over climate change. On Tuesday, the G-8 nations - the United States, Japan, Germany, France, Britain, Italy, Canada and Russia - embraced the goal of halving the global emissions by 2050 as part of a larger deal to be brokered by the UN by the end of next year. In accordance with its expanded format that included leaders from Africa and major developing nations, the G-8 focused much of their discussion on rising oil prices and their effect on the global economy, development aid and the food crisis buffeting Africa, South Asia and other poorer regions. On oil, G-8 nations called for expanded production and investment to boost supplies, while endorsing greater energy efficiency. They also pointed out that they had pledged US$10 billion in food and other aid, and said they would form a global partnership on food and agriculture to buoy production. The leaders also pledged renewed determination to meet goals announced at previous summits to boost annual aid to Africa by US$25 billion, and to spend some US$60 billion to battle infectious diseases. Studies show that the G-8 has so far only provided US$3 billion of the overall aid so far, and they planned an oversight mechanism to keep them to their promises. Climate, however, commanded the most attention at the summit in Toyako, northern Japan. Host Japan had prepared for more than a year to win support for the 2050 target, though the agreement on that goal fell far short of ambitions by some European countries and developing nations eager to see wealthy nations take on shorter term targets for 2020 in the run-up to the conclusion of the UN talks next year. "The success or failure of the whole accord will be decided by the question of the mid-term targets," German Chancellor Angela Merkel said. "Unless the industrial nations set ambitious midterm targets, the developing nations will not set any targets at all." The Major Economies Meeting on Wednesday faced considerable criticism from environmentalists because the final statement lacked specific targets and did not include small island states and others considered most vulnerable to the effects of global warming, such as rising oceans. The US, however, insisted the meeting represented progress. "In order to address climate change, all major economies must be at the table, and that's what took place today," US President George W. Bush said in a statement to reporters after the meeting, which capped nearly a year of discussions. Bush has long insisted that China - by some accounts the world's largest emitter of greenhouse gases - and India be called on to take strong action on climate. But Chinese President Hu Jintao, in comments before the group, insisted that wealthy nations must take the lead in reducing emissions, and provide clean technology transfer and financing to support developing nations' efforts to control emissions and adapt to rising temperatures. Hu also defended China's environmental efforts, pointing out that his country is still developing, and that its per capita emissions are still relatively low. He also noted China's efforts to boost energy efficiency and increase forest cover. Environmentalists deplored the G-8 action on climate change, saying it fell short of pushing forward the UN talks, which have been hampered by deep divisions. "The last three days have contributed very little to solving the global warming problem," said Alden Meyer of the Union of Concerned Scientists. "We have no near-term emissions reductions commitments by the G-8." Zimbabwe was the top political item on the agenda. Leaders condemned President Robert Mugabe, whose followers are accused of leading a campaign of murder against opposition supporters, leading to a one-candidate race that Mugabe easily won last month. The G-8 branded his rule as illegitimate, promising to take measures against those responsible for the violence that prompted the opposition candidate to pull out of the race. "There can be no hiding place for those people who are part of the cabal supporting Mugabe," British Prime Minister Gordon Brown said Wednesday. "The election that Mugabe claims legitimate is not an election that is free or fair."