IPCC critical of climate change report leak
The UN climate science panel has criticised a blogger who has published a draft version of its next report.
The Intergovernmental Panel on Climate Change (IPCC) is preparing what is known as its Fifth Assessment Report for publication next year.
The work looks to draw together research to provide a statement on global warming and its future effects.
The drafting of the reports is open to reviewers but on the condition that no details are published.
In a statement, the IPCC says it "regrets this unauthorized posting which interferes with the process of assessment and review".
The draft posted online is of what's called Working Group 1 (WGI), the first stage of the next report.
This covers the physical aspects of climate science, including observations of temperature and computer models of possible scenarios for future warming.
The IPCC statement read: "The unauthorized and premature posting of the drafts of the WGI AR5, which are works in progress, may lead to confusion because the text will necessarily change in some respects once all the review comments have been addressed.
"It is regrettable that one out of many hundreds of reviewers broke the terms of the review."
The draft was posted by US climate sceptic Alec Rawls, who runs a blog called Stop Green Suicide.
It is reported that he highlighted one particular sentence in the draft - about the possible effect of cosmic rays on the climate - claiming it undermined the case that most recent warming has been driven by man-made greenhouse gases.
However, when the BBC attempted to access the blogger's site it was not available but a number of other sites were providing links to places where the report could be viewed or downloaded online.
Climate scientists, reacting to the leak, have condemned the "cherry picking" of this one point in a long report and have said that other sections reinforce the central argument about the cause of climate change.
In any event, the text faces several further stages of possible revision before publication late next year.
A meeting of lead authors in Tasmania next month will be the next chance to review all the latest comments.
One lead author, Richard Betts of the Met Office, tweeted that further alterations were likely.
"Worth pointing out that the wording in the leaked IPCC WG1 draft chapters may still change in the final versions, following review comments," he wrote.
The leak highlights a fundamental question about the way the IPCC is managed in the age of the internet.
While it aims to be open to all contributions, the system of conducting the drafting and discussions in private has long been under pressure.
Prof Piers Forster of Leeds University, UK, said the rationale behind the IPCC process was "to iron out all the errors and inconsistencies which might be inadvertently included.
"Personally, I would be happy if the IPCC process were even more open and public, and I think we as scientists need to explore how we can best match the development of measured critical arguments with those of the Twitter generation."
This comes as the IPCC is under intense pressure following the discovery of errors in its last assessment, released in 2007.
An inquiry by the Inter Academy Council concluded in 2010 that the IPCC needed better management to handle the growing complexity of climate science and the scrutiny of the outside world.
The panel's reports are designed to provide a consensus statement on the latest climate science to help governments decide how to respond.