Image caption Rajendra Pachauri faced calls to resign over doubts on the IPCC's science in September

The Intergovernmental Panel on Climate Change has adopted new guidelines on dealing with scientific uncertainties following criticism of its 2007 report.

But the panel's meeting in South Korea closed with many other reforms proposed in a recent review being passed to committees for further consideration.

Chairman Rajendra Pachauri confirmed his intention to stay in post until the next assessment is published in 2014.

Dr Pachauri said the talks marked a milestone in the panel's history.

"The IPCC is 22 years old, it's evolved and seen a number of changes; but in the past few years we've also seen major changes in the global context in which it works," he said.

"The decisions made here in Busan send a clear message - we need to get to work and we need to do much better than ever before, and to work harder than ever before," he said.

The new guidance on uncertainties is aimed at preventing too much confidence being ascribed to conclusions where evidence is scarce.

In its recent review of the IPCC, the InterAcademy Council (IAC) - an umbrella group for the world's science academies - highlighted a case in the 2007 assessment where studies projecting rapidly declining crop yields in Africa were given more weight than they merited, in the absence of supporting evidence.

The revised guidance emphasises that in future, authors must assess both the quality of research available and uncertainties within that research.

I have every intention of staying right until I have completed the mission I accepted voluntarily to carry out Rajendra Pachauri, IPCC Chairman

It urges authors to be careful of "group-think", but maintains that it "may be appropriate to describe findings for which the evidence and understanding are overwhelming as statements of fact without using uncertainty qualifiers".

Enhanced guidance on the use of "grey literature" - material not published in peer-reviewed scientific journals - has also been drawn up, and will be finalised by chairs of the IPCC's working groups in the coming months.

Procedures for correcting errors should they arise were also approved - which means that the most serious error in the 2007 report, on the projected melting date for Himalayan glaciers, can be formally repaired.

"Some aspects of that error have been corrected and are now incorporated in the text," said Chris Field from the Carnegie Institution at Stanford University in California, who co-chairs the IPCC working group on climate impacts.

"But for other elements, we didn't really have the procedures in place until the error correction protocols were approved today.

"So the first order of business once I get back to my office is to initiate the procedure to do the definitive correction on the Himalayan glaciers."

Governance questions

Following allegations of conflict of interest against Dr Pachauri and other prominent climate scientists, the IPCC also endorsed IAC calls to establish a protocol for dealing with such issues in future.

But while some figures outside the IPCC have called for Dr Pachauri's head, government delegates here supported him continuing in post.

"I not only have the mandate to oversee the completion of AR5, but having been one of the two parties that requested a review by the IAC (the other being the UN), I now also have a commitment to oversee the implentation of the reforms that have come out of the review process.

"So I have every intention of staying right until I have completed the mission I accepted voluntarily to carry out, namely the conclusion of AR5 in 2014."

The IAC recommendation that senior officials - including the chair - should be limited to a single term of office will go forward to committee, with some delegates concerned about a lack of continuity.

Also going to committee is the recommendation that the IPCC reform its management - by taking on a full-time executive director to complement the part-time role of the chair, and by establishing an executive committee that could make decisions in periods between full meetings.

In response to suggestions that the panel had simply kicked these issues into touch, Thelma Krug from Brazil's National Institute for Space Research, who leads the IPCC's task force on measuring greenhouse gas emissions, said governments had simply wanted more clarity.

"The general feeling of the panel was that an executive committee was necessary," she said.

"But if we follow the recommendation of the IAC, it says the committee should act on the IPCC's behalf. That's a very strong statement - to 'act on its behalf' - so initially countries would like to know the mandate they will be giving to the executive committee to act on their behalf."

The aim is to reach agreement on these issues at the next full meeting in May 2011.

The IPCC, which is ultimately controlled by its 194 member governments, is charged by the UN system with producing regular systematic evaluations of global climate change and its implications.

The next assessment will be the fifth since the panel's inception - and the assessment procedure begins next month.