Climate scientists who worked on the UN panel on global warming have hit out at "sloppy" colleagues from other disciplines who introduced amistake about melting glaciers into the landmark 2007 report.
The experts, who worked on the section of the Intergovernmental Panel on Climate Change (IPCC) report that considered the physical science of global warming, say the error by "social and biological scientists" has unfairly maligned their work. Some said that Rajendra Pachauri, the panel's chair, should resign, though others supported him.
The IPCC report combined the output from three independent working groups, which separately considered the science, impacts and human response to climate change, and published their findings several months apart.
Speaking on condition of anonymity, several lead authors of the working group one (WG1) report, which produced the high-profile scientific conclusions that global warming was unequivocal and very likely down to human activity, told the Guardian they were dismayed by the actions of their colleagues.
"Naturally the public and policy makers link all three reports together," one said. "And the blunder over the glaciers detracts from the very carefully peer-reviewed science used exclusively in the WG1 report."
Another author said: "There is no doubt that the inclusion of the glacier statement was sloppy. I find it embarrassing that working group two (WG2) would have the Himalaya statement referred to in the way it was."
Another said: "I am annoyed about this and I do think that WG1, the physical basis for climate change, should be distinguished from WG2 and WG3. The latter deal with impacts, mitigation and socioeconomics and it seems to me they might be better placed in another arm of theUnited Nations, or another organisation altogether."
The scientists were particularly unhappy that the flawed glacier prediction contradicted statements already published in their own report. "WG1 made a proper assessment of the state of glaciers and this should have been the source cited by the impacts people in WG2," one said. "In the final stages of finishing our own report, we as WG1 authors simply had no time to also start double-checking WG2 draft chapters."
Another said the mistake was made "not by climate scientists, but rather the social and biological scientists in WG2 ... Clearly that WWF report was an inappropriate source, [as] any glaciologist would have stumbled over that number."
The discovery of the glaciers mistake has focused attention on the IPCC's use of so-called grey literature: reports that do not appear in conventional scientific journals, and are instead drawn from sources such as campaign groups, companies and student theses. The IPCC's rules allow such grey literature, but many people have been surprised at the scale of its inclusion.
The report from WG2 cited the erroneous WWF report again, though not the glacier claim, in a separate section on human health, and also referenced reports from Greenpeace, the World Resources Institute, wildlife trade group Traffic as well as insurance companies Swiss Re and Axa. Working group three draws extensively on grey literature, including a newspaper article from the Asia Times.
Most WG1 scientists contacted by the Guardian defended the use of grey literature. "In many cases these reports have to use grey literature and anecdotal evidence because there is nothing else available, for example reports of sea level rise on small island states."
Another author said: "Part of the problem is that WG2 largely involves the social science community. They are more used to referring to a diversity of sources, in fact, expert opinion is also an important analysis tool in the social sciences."
Several authors defended Pachauri and the IPCC process. "The IPCC is not a hierarchical, top-down organisation. The chapter authors have great freedom in writing their assessment without interference from the top, and so it should be."
"This is a transient and manufactured crisis and will likely go away with time," one IPCC author said. "What the science community needs is a few huge donors to throw millions of dollars behind PR campaigns to counter the propaganda out there. We are being attacked through baseless smear campaigns and we are not PR experts."
They added: "The sad reality is this whole manufactured climate controversy is like arguing over the dinner menu on the Titanic as it sinks. The fact is, the climate is warming. Do we want to deal with this problem or not? Do we owe anything to future generations who are not here today to be part of the decision-making process. Science and the IPCC cannot answer these questions."