A congressional report used by Rep. Joe Barton (R-TX) to question the validity of the science behind global warming in a 2006 hearing was highly plagiarized, according to experts who reviewed it.

"The report was integral to congressional hearings about climate scientists," Aaron Huertas of the Union of Concerned Scientists explained. "And it preceded a lot of conspiratorial thinking polluting the public debate today about climate scientists."

The report was requested by Barton in 2005, when he was the head of the House Energy and Commerce Committee, a position he is currently trying to reclaim. In 2006, he said that global warming science is "pretty weak stuff."

Plagiarism experts told USA Today that the report, which was authored by George Mason University statistician Edward Wegman, copied material from textbooks, Wikipedia, and other sources.

John Mashey, a retired computer scientist, conducted a year-long analysis of the Wegman report and found that 35 of the report's 91 pages "are mostly plagiarized text, but often injected with errors, bias and changes of meaning."

The Wegman report was highly critical of the "hockey stick graph," a chart of temperature variation over the last 1,000 years that showed a sharp increase during the last 100 years. That graph was first published in a 1998 report authored by climate scientists Michael Mann, Raymon Bradley, and Malcom K. Hughes. A version of the graph was later used in Al Gore's movie "An Inconvenient Truth."

Wegman and his colleagues relied heavily on a report by two Canadians with no formal education in climate science, mining consultant Stephen McIntyre and economist Ross McKitrick, who criticized the graph, but did not bother contact the authors of the graph, Mann and Bradley, for information. Although the McIntyre-McKitrick paper did catch some statistical errors in the "hockey stick graph," it did not completely invalidate Mann and Bradley's research.

"Subsequent studies have found while there was some valid criticism of the statistical methods in the original graph, the McIntyre-McKitrick paper introduced some of its own errors and reached a flawed conclusion," Kate Sheppard of Mother Jones explained. "The paper does not, in fact, invalidate the hockey stick—particularly since numerous other studies have reinforced the Mann-Bradley findings. Moreover, Mann and his colleagues acknowledged in the original paper that there are uncertainties and that further study was needed on the subject."

One of the textbooks plagiarized by the Wegman report was Bradley's Paleoclimatology: Reconstructing Climates of the Quaternary.

A spokesman for George Mason University, where Wegman is employed, says the "matter is under investigation."

"I will say that there is a lot of speculation and conspiracy theory in John Mashey's analysis which is simply not true," Wegman said Monday. "These attacks are unprecedented in my 42 years as an academic and scholar. We are not the bad guys and we have never intended that our Congressional testimony was intended to take intellectual credit for any aspect of paleoclimate reconstruction science or for any original research aspect of social network analysis."

Robert Coleman, who chairs Ohio State University's misconduct committee, said "the plagiarism is fairly obvious when you compare things side-by-side."

"It's nothing personal. I don't want these guys fired or anything," Bradley said. "They should just retract or withdraw the report as you would any scientific publication that has these sort of problems."