It may be time for the United Nations' climate-studies scientists to go back to school.
A group of 40 auditors -- including scientists and public policy experts from across the globe -- have released a shocking report card on the U.N.'s landmark climate-change research report.
And they gave 21 of the report's 44 chapters a grade of "F."
The team, recruited by the climate-change skeptics behind the website NoConsensus.org, found that 5,600 of the 18,500 sources in the Intergovernmental Panel on Climate Change's (IPCC) Nobel Prize-winning 2007 report were not peer reviewed.
"We've been told this report is the gold standard," said Canadian global-warming skeptic Donna Laframboise, who runs the NoConsensus.org site and who organized the online effort to examine the U.N.'s references in the report, commonly known as the AR4.
"We've been told it's 100 percent peer-reviewed science. But thousands of sources cited by this report have been nowhere near a scientific journal."
Based on the grading system used in American schools, 21 chapters in the IPCC report received an F for citing peer-reviewed sources less than 60 percent of the time. Four chapters received a D, and six received a C.
The report also got eight A's and five B's from the auditors, who included Bob Ashworth, a member of the American Geophysical Union, and Dr. Darko Butina, a director of Chemomine Consultancy Ltd.
According to Lafromboise, much of the scientific research published by the U.N. cited press releases, newspaper and magazine clippings, student theses, newsletters, discussion papers, and literature published by green advocacy groups. Such material is often called "gray literature," she said, and it stands in stark contrast to the U.N.'s claims about the study's sources.
In June 2008, Rajendra Pachauri, the IPCC's chairman, said: "People can have confidence in the IPCC's conclusions, given that it is all on the basis of peer-reviewed literature.
"We don't pick up a newspaper article and, based on that, come up with our findings," he told a group at the Commonwealth Club.
The U.N. is not commenting in depth on the audit, but it has acknowledged its existence. Isabel Garcia-Gill, a spokeswoman for the IPCC in Geneva, told FoxNews.com that the U.N. knows of what she terms the "Laframboise report." She declined to answer further questions, and she asked that queries be sent by e-mail; she did not respond to such e-mails.
But not everyone agrees that "gray literature" is bad sourcing for a study. "The category of so-called gray literature includes valuable information that the IPCC -- and we -- shouldn't ignore," argued Peter Frumhoff, chief scientist at the Union of Concerned Scientists and a lead author of the deforestation section of the last IPCC report.
"Handing out negative grades to the IPCC for simply being thorough is wrong," he said, adding that the IPCC should "look at all the information, including peer-reviewed papers as well as gray literature, which includes government reports and other important information sources. By and large, the IPCC process works exceptionally well and the independent review of IPCC procedures now underway will assess opportunities for further strengthening it."
Monique Hanis, a spokeswoman for the Solar Energy Industries Association, downplayed the importance of the report, saying that despite a handful of errors, there is still a pressing need for cleaner energy to help combat climate change.
"Regardless of the debate on the science of climate change, the facts are that we still need to reduce pollution, increase renewable energy sources and shift to a clean energy future," she said. "And despite the disappointing climate change event in Copenhagen, many of us in the industry are simply moving forward."
But other policy experts were unsurprised by the report. Dan Miller, a spokesman for the Heartland Institute, a non-profit think tank that is hosting a global warming conference next month in Chicago, said the bad grades given to the U.N. were apt.
"The IPCC deserves every stroke of its 'F' grade," Miller told FoxNews.com. "Not only is the data used in the report flawed and suspect, but even more egregiously, the IPCC authors -- very few of whom indeed are scientists -- refused to consult with scientists who are skeptical of the IPCC's defining hypothesis: that the Earth faces a crisis from rising global temperatures and that human activity played a significant role."
"The authors' closed minds are a trait typical of propagandists, not scientists," he added.
Roni Bell Sylvester, editor of environmental policy site Land and Water USA, told FoxNews.com: "Any policy already made that is connected in any way to climate change/global warming/CO2 theories must be rescinded. Any policy in the works that is connected in any way to climate change/global warming/CO2 theories must be aborted."
There are still many who support restrictions on carbon emissions. A spokeswoman for carbon-accounting software firm Hara told FoxNews.com that the need for limits "will only get more critical, with climate-change legislation heating up in Cancun this fall." Corporate giants like Coca-Cola, and Safeway, are among Hara's customers, and venture funding is being provided by the firm Kleiner Perkins.
Others are calling for a more cautious approach than spending public or private dollars on discredited scientific research. "The correct policy to address this non-problem is to have the courage to do nothing," said Lord Christopher Monckton, who was a science adviser to former British Prime Minister Margaret Thatcher and now is chief policy adviser to the Science and Public Policy Institute.