A confidential draft of a high-level international report on the state of climate change has been posted on the internet by US officials months before it was due to be made public. The move to effectively publish the findings of the influential Intergovernmental Panel on Climate Change (IPCC) has surprised experts, who say it could undermine the final report when it is released in February.
The IPCC's fourth report draws together research over the last five years to predict the likely course of global warming. The draft was sent to governments for comment last month.
One British climate scientist and senior author of the IPCC report, who did not want to be identified, said: "They definitely shouldn't have done that. I'm very surprised. If you put a draft document in the public domain then people will start quoting it."
Others say the move could be a deliberate attempt to reduce the impact of the final report. The Bush administration has been critical of the IPCC and its conclusions, which form the basis for international action to reduce greenhouse gas emissions through the Kyoto protocol. The new report will underpin negotiations to extend the protocol beyond 2012.
Roger Pielke, a climate policy expert at the University of Colorado, said: "I do have some suspicions. If the report is out there and the findings have been discussed, then it deflates the newsworthiness of the official report when it is released."
The draft report reflects a debate that has moved on from whether man-made climate change is real to what the effects could be. It says human activity since the industrial revolution is "very likely" to be warming the planet and "more likely than not" to be behind an observed increase in the intensity of tropical cyclones.
It was posted on the web by the US Climate Change Science Programme, a government office that coordinates global warming research, which said it made the report available for "expert comment" to help frame its official response. Its website says participants should not quote or redistribute the document, which can be accessed with a password provided automatically to anyone who sends an email.
The office has contacted thousands of scientists, environmental groups and industry lobbyists. Most other countries have solicited comments from a small number of experts, who are asked to judge whether the report accurately reflects scientific thinking. The IPCC process allows individuals to request a copy of the draft report, but requires them to prove their scientific expertise.
Staff at the Climate Change Science Programme referred questions to Harlan Watson, senior climate negotiator at the state department, who said: "I find it quite ironic that running an open process would be criticised. What we're doing is providing an opportunity for people to comment. It's not for us to say who the experts are."
Officials at the IPCC could not be contacted for comment. Rajendra Pachauri, the panel's chairman, did not learn of the US move until the report was posted.
Set up in 1988 by the UN, the Intergovernmental Panel on Climate Change brings together hundreds of experts to summarise the state of climate science for policymakers.
It has produced three reports since 1990, each of which has been instrumental in establishing national and international strategies to address global warming.
Government officials have until next month to comment on the new draft, when scientists will gather in Bergen, Norway, to produce a final version.
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