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Acknowledging flaws in its reports and growing public skepticism toward the theory of manmade global warming, the United Nations hired an independent review panel in March to audit its climate-science arm. The group found plenty of problems.

The InterAcademy Council, an independent group of scientists representing agencies from around the world, presented the findings of its five-month investigation Monday morning at the United Nations. The group took issue with the structure, methods and leadership of the U.N.'s Intergovernmental Panel on Climate Change (IPCC) -- the group responsible for a 2007 report that erroneously forecast the imminent melting of Himalayan glaciers, the rate of melt of polar ice caps and dwindling Amazon rainforests.

"The IPCC has raised public awareness of climate change, and driven policymakers," said Harold Shapiro, chair of the IAC Committee to Review IPCC and former president of Princeton University. But the controversies that have erupted, and revelations of errors, have put the group under the microscope. "We recommend some significant reforms," he told the U.N.

"The IPCC has yet to review the IAC's findings, so I am not able to comment on its findings," said longstanding chair Rajendra Pachauri in a press conference following the presentation. But he did note that none of the seven reviews of the IPCC to date had found flaws in the U.N. group.

"The scientific community agrees that climate change is real,"  Pachauri said.

Despite his confidence, the science underlying climate change has come under great scrutiny. Yet the IAC did not spend its time analyzing the accuracy of climate models and climate science.

"We did not redo the science," said Shapiro. Instead, the IAC focused its attention on the procedures and methodologies of the IPCC, suggesting many areas for improvement.

The rate of melt of the Himalayan glaciers was one touchstone among skeptics of manmade global warming that the group addressed. Shapiro explained that many reviewers noted the lack of substance behind the claim, but their criticism didn't make it into the final report.

It appears that editors "didn't follow through carefully enough on what review editors commented," said Shapiro.

The IAC faulted the IPCC for making this type of mistake in several places, noting that the report includes several statements that are assigned high levels of confidence, Shapiro told the U.N., despite a lack of sufficient evidence behind them.

"We found in the summary for policymakers that there were two kinds of errors that came up -- one is the kind where they place high confidence in something where there is very little evidence. The other is the kind where you make a statement … with no substantive value, in our judgment."

Revising and tightening up the complex and lengthy review policy would help to address these issues.

Noted climate skeptic Don Easterbrook, an emeritus professor of geology at Western Washington University, agreed that this type of issue was a problem. "The IPCC report is filled with statements of '90% certainty' without even saying 90% of what or providing any basis for such statements. Yet those pronouncements of certainty were used over and over as though that had been scientifically proven somehow," he told FoxNews.com.

The IAC called for the IPCC to completely revise top leadership, including limiting the duration of people in top positions and "electing a small executive committee to act on its behalf," one that even included non-scientists. This would lend it credibility, Shapiro said.

Questions have arisen about conflicts of interest among top leadership at the IPCC, notably chair Pachauri, who sits on the boards of numerous other climate-related groups. Shapiro stressed that this important issue was one the group did not investigate -- "we didn't consider it our charge to investigate that issue," he replied.

Easterbrook thinks this suggestion may not go far enough.

"The IAC report makes several recommendations to fortify IPCC’s management structure, including establishing an executive committee to act on the panel’s behalf and ensure that an ongoing decision-making capability is maintained. This would be a step in the right direction, but if such an executive committee is made up of the same old political cronies, nothing will change," he told FoxNews.com.

The IAC took issue with the IPCC's use of so-called gray literature as well, papers from unpublished or non-peer-reviewed sources. Such material is explicitly against policy, yet authors of the IPCC's reports do not follow the guidelines for evaluating such sources, explained the IAC.

The group recommended that these guidelines be made more specific -- including adding guidelines on what types of literature are unacceptable -- and strictly enforced to ensure that unpublished and non-peer-reviewed literature is appropriately flagged.

The Union of Concerned Scientists, a nonprofit group that supports the concept of manmade global warming, agreed with the IAC's report, calling it "a great opportunity to strengthen" the group, but not a wholesale call to rework the agency.

"It's a substantial tune up, but not a replacement with a new vehicle," Peter Frumhoff, director of science and policy for the UCS, told FoxNews.com. "All the recommendations I've seen are really spot on. We'll see what happens when the IPCC meets in October."

The IAC's assessment will be used at the Oct. 5 meeting that marks the beginning of the IPCC's effort to put out the next report.

"The IPCC has been successful overall, but fundamental changes are needed," Shapiro said.