A MISTAKE about the timing of melting glaciers has snowballed into an unprecedented assault on the credibility of climate science, after revelations that an author of the United Nations Intergovernmental Panel on Climate Change's report knew that one passage was wrong but included it anyway.
Pressure is now mounting on the head of the IPCC, Rajendra Pachauri, with further elements of the IPCC's report being brought into question and the separate announcement of a government inquiry into climate data in Britain.
As well as the glacier mistake, the IPCC said at the weekend that it would re-examine a passage about the relationship between climate change and extreme weather events such as hurricanes in its 2007 report.
Scientists who uncovered the error about the timing of melting glaciers in the Himalayas told the Herald that the conclusions of the report are right, and that fixing such errors are a routine part of the scientific process.
An Australian lead author of the report, Professor Andy Pitman, also said the mistake did not affect the veracity of the UN body's conclusions. He said that scientists were being subjected to ''an orchestrated campaign that's exactly the same as that was used by the smoking lobby to try and discredit science''.
The author of the offending passage in the IPCC's working group report, Dr Murari Lal, has conceded that the claim that Himalayan glaciers could melt by 2035 is not supported by peer-reviewed science, but said he included it anyway.
''It related to several countries in this region and their water sources,'' he was quoted as saying in Britain's Daily Mail newspaper. ''We thought that if we can highlight it, it will impact policymakers and politicians and encourage them to take some concrete action. It had importance for the region, so we thought we should put it in.''
Dr Lal's passage ignored the IPCC's guidelines on using peer-reviewed science as a basis for its assertions, and the UN body conceded last week that it should have been edited out of its working group report.
However, the inaccurate passage was not included in the ''summary for policymakers'' section of the report which forms the basis of government responses to climate change.
As the Herald revealed on Saturday, the flaw was highlighted during the review process in August 2006 and had been shown to be wrong several times before and since the report's publication.
One of the expert reviewers who picked up the error, Dr Hayley Fowler of Newcastle University in Britain, said her own research had suggested the claim was wrong.
Dr Fowler, a hydroclimatologist, pointed out that while winters in the western Himalayas were warmer, summers had been cooler in recent years, meaning that some glaciers in the west have been growing, not receding like others around the world.
Dr Fowler said the scale of the task of putting the report together meant that no one editor could be an expert on every aspect of each chapter. ''Given the size of literature that needs to be read to put the IPCC report together though, I am sure that occasional errors may occur,'' she told the Herald. ''The good thing is that it has been spotted and will now be put right. It does not mean that all the other conclusions of the IPCC report are wrong.''
A British parliamentary committee will examine the theft of data and emails from the University of East Anglia last year and examine the implications for scientific research.
Professor Pitman joined other scientists from within and outside the IPCC to say that the errors in the 2007 report should be seen in context.
''There are 1600 pages in the working group reports and after two years there are two paragraphs which have been found to have errors in them. By any standard these are remarkably accurate documents, but I don't believe anyone ever said they were perfect. The point of research is that we pick up errors like this.''
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