An independent review panel hired by the United Nations says the U.N.'s Intergovernmental Panel on Climate Change needs a major overhaul.

The InterAcademy Council warned the group should stick to science and to stay away from advocacy when it comes to their views on climate change.

Recently, the credibility of the panel has been questioned because of some mistakes made over the last two years.

The resulting negative review has put pressure on the controversial chairman Rajendra Pachauri to step down. So far, he hasn't given any indication that he will resign.

"It's hard to see how the United Nations can both follow the advice of this committee and keep Rajendra Pachauri on board as head," Roger Pielke Jr., a frequent critic of the Intergovernmental Panel on Climate Change, told the Associated Press.

The 113-page review was requested by the IPCC and the U.N. after the errors were found. The quality of the science itself wasn't studied, although former Princeton University president Harold Shapiro, who led the review of the IPCC, said the key recommendations in the climate report "are well supported by the scientific evidence."

Still, he said the way the report expressed confidence in scientific findings was incomplete and at times even misleading.