 Scientists clashed with government officials at a UN panel on climate change on Friday over how strongly global warming is affecting plants and animals and the degree to which humans are causing temperatures to rise. More than 100 nations in the UN group agreed a final text after all-night talks that were punctuated by protests from researchers, who accused delegates of ignoring science and watering down a summary version of the report for policymakers. Environmentalists say governments tried to weaken the report in order to avoid taking strong measures to reduce greenhouse gas emissions. China, Russia, and Saudi Arabia were the main culprits at the meeting, delegates said. "It looks like very blatant vested interests are trying to stop particular messages getting out," said Neil Adger from Britain's Tyndall Centre for Climate Change Research. "We give our best to provide the best scientific assessment, but when the wording of that is then changed ... we get very upset. It's three years' work." He said delegates had also tried to weaken the link between greenhouse gas emissions caused by humans and the impacts of global warming worldwide. The Intergovernmental Panel on Climate Change (IPCC) groups 2,500 scientists and is the top authority on climate change. Cynthia Rosenzweig of the NASA Goddard Institute for Space Studies submitted a letter of protest to the IPCC chairman after Chinese delegates insisted on cutting a reference to 'very high confidence' that climate change was already affecting natural systems on all continents and in some oceans, she said. "I did make a statement that the authors strongly felt that the 'very high confidence' level was right," she told reporters after the meeting. "I was protesting because I felt the science wasn't brought forward." She left the meeting after the protest but said she needed a break and had not staged a walkout. The delegates ended up taking out any reference to confidence and revised the text to say: "Observational evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases." Martin Parry, co-chair of the group preparing the report, denied the document had been weakened as a whole. "I don't think it would be a right story to say it was watered down. Certain messages were lost but I don't think in any respect the message was lost," he said. "When you have big meetings, there is a boiling down to common ground." But although Rosenzweig said she was happy with the compromise, many scientists felt the summary was not as sound as the larger report that they are preparing. "There is some residual frustration amongst the scientists. There's no question about that," said Kevin Hennessy, senior research scientist at the Climate Impact Group in Australia and another lead author. "But we're going to encourage people to drill down to the more detailed information in the technical summary and in the individual chapters." 