The review committee, which did not evaluate the scientific conclusions made by the United Nations panel, said the way the panel went about its work was “successful over all.”…

The committee noted that some climate panel leaders had been criticized for public statements perceived as advocating specific policies. “Straying into advocacy can only hurt I.P.C.C.’s credibility,” the report said.

It also suggested that the panel revise the way it rates doubts about some of the science, that the process of choosing the scientists who write the report be more open and that the panel require that any possible conflicts of interest be revealed.