The head of the United Nations Environment Programme (UNEP) Monday underlined the crucial leadership role in unlocking the complexities of climate change played by the panel tasked with preparing regular scientific reports on the issue.

In August, an independent review called for major changes in management and procedures to enable the Nobel Peace Prize-winning Intergovernmental Panel on Climate Change (IPCC) to strengthen the quality of its assessments.

In March, Secretary-General Ban Ki-moon and IPCC Chair Rajendra Pachauri requested the review amid intense public debate about the science of climate change, as well as questions over the accuracy of the UN-backed panel's reports.

In 2007, the IPCC issued its landmark Fourth Assessment Report, which found the warming of the climate is outpacing natural variability, driven largely by human activity. The panel's credibility came into question after revelations that the report contained some mistakes, including over the rate of Himalayan glacier melt.

"It has certainly had consequences in terms of public opinion and the public policy arena," UNEP Executive Director Achim Steiner said in a message to the 32nd plenary session of the IPCC, which kicked off today in Busan, Republic of Korea.

He urged the body to use the five-day event to re-assert its leadership and restore public confidence in the IPCC, which is set to issue its Fifth Assessment Report between 2013 and 2014.

"Indeed, a rigorous, credible and convincing [Report] – at least in terms of the global public – may in part rest on your decisions here in terms of this scientific body and the way it operates and communicates," Mr. Steiner noted.

He pledged UNEP's assistance to help Member States implement recommendations made by the independent review.

The UNEP head underlined that the IPCC's "admirable" work is "essential in unravelling the complexities of climate change, where new science, requesting and requiring new understanding, emerges almost daily."

In an address to another meeting that kicked off today, Mr. Steiner urged nations to take fresh action to curb possible harm to human and biological diversity from biotechnology.

More than 4,000 people are attending the five-day gathering on the Cartagena Protocol on Biosafety, the first legally-binding international treaty on the safe transfer, handling and use of living modified organisms (LMOs) resulting from modern biotechnology.

Since the pact's adoption ten years ago, "real and tangible progress has been made by the Parties in an area of environmental sustainability that is often fraught with polarized views and strong, sometimes contradictory, positions," Mr. Steiner said.

The Protocol's real impact "will only be felt when all countries have the necessary human and institutional capabilities," he stressed, underlining the importance of meeting funding targets.

"In a globe struggling with multiple challenges – from climate change and loss of biodiversity to collapsing fisheries and chemical pollution – countries urgently need to demonstrate leadership," the official said.