The IPCC came under fire after using the wrong date for Himalayan glacier melt
The UN's climate science body needs fundamental reforms to the way it is managed, an international review has concluded.
The Intergovernmental Panel on Climate Change (IPCC) has faced mounting pressure over errors in its last major assessment of climate science in 2007.
The review commends the IPCC on the way it carried out previous assessments.
But the report recommends changes to the way the body is run and the way science is presented.
The IPCC has admitted it made a mistake in its 2007 climate assessment in asserting that Himalayan glaciers could disappear by 2035.
But officials at the UN organisation said this error did not change the broad picture of man-made climate change.
Dr Pachauri has said he welcomes a "vigorous debate" on climate science
The review was overseen by the Inter-Academy Council (IAC), an international umbrella body for science academies.
The IAC committee charged with examining the IPCC's workings recommended that the UN body appoint an executive director to handle day-to-day operations and speak on behalf of the body.
It also said the current limit of two six-year terms for the chair of the organisation is too long.
The report says that the post of IPCC chair, currently occupied by Dr Rajendra Pachauri, and that of the executive director should be limited to the term of one climate science assessment.
Dr Pachauri became head of the organisation in 2002 and was re-elected for his second term in 2008.
Speaking at news conference in New York, Harold Shapiro, who chaired the IAC committee's review, said: "Overall, in our judgment, the IPCC's assessment process has been a success and has served society well."
But he said fundamental changes would help the IPCC continue success under a "public microscope". Dr Shapiro also conceded that the controversy over errors in climate science assessments had dented the credibility of the process.
The report also suggests the UN body establish an executive committee which should include individuals from outside the IPCC or even outside the climate science community in order to enhance the UN panel's credibility and independence.
The review did not address the state of knowledge in climate science, but instead concentrated on review processes at the UN body, including the use of non-peer reviewed sources, and quality control on data.
The review committee said the processes used by the UN panel to review material in its climate assessment reports were thorough. But the IAC said that the IPCC's response to revelations of errors in its 2007 assessment had been "slow and inadequate", adding that procedures needed stronger enforcement to minimise the number of errors.
Review's terms of referenceAnalyse the IPCC process, including links with other UN agenciesReview the use of non-peer reviewed sources, and quality control on dataAssess how procedures handle "the full range of scientific views"Review how the IPCC communicates with the public and the media
The review also called for more consistency in how the IPCC's different working groups characterised uncertainties in climate science.
The report says that each working group used a different variation of the IPCC's uncertainty guidelines and the committee found that the guidance was not always followed.
The use by the IPCC of so-called "grey literature" - that which has not been peer-reviewed or published in scientific journals - has been subjected to particular scrutiny of late, partly because this type of material was behind the glacier error.
The committee said that such literature was often relevant and appropriate for inclusion in the IPCC's assessment reports. But it said authors needed to follow the IPCC's guidelines more closely and that the guidelines themselves are too vague.
The report's recommendations are likely to be considered at the IPCC's next plenary meeting in Busan, South Korea, from 11-14 October.
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