The embattled head of UN's climate change panel, R K Pachauri, faced fresh pressure to step down with one of the leading figures in the environment movement saying that the Nobel Prize winning body needs a new leader to regain its credibility.
Director of Greenpeace UK, John Sauven said Pachauri made a flawed judgement by not registering the mistake made by the Intergovernmental Panel on Climate Change (IPCC) which came to light ahead of the Copenhagen conference.
Pachauri, has insisted he would not step down in the wake of the controversy that the climate report by his panel had exaggerated claims of global warming and based its results on uncorroborated facts.
"Mistakes will always be made but it's how you handle those mistakes which affects credibility of the institution. Pachauri should have put his hand up and said we made a mistake.
"It's in these situations that your character and judgement is tested. Do you make the right judgement call? He clearly didn't," Sauven said.
The IPCC issued a correction and apology on January 20, three days after the error had made global headlines.
Sauven said the IPCC needed a new chairman who would hold public confidence by introducing more rigorous procedures.
"The IPCC needs to regain credibility... If we get a new person in with an open mind, prepared to fundamentally review how IPCC works, we would regain confidence in the organisation," he said.
Sauven said the body needs someone "held in high regard who has extremely good judgement and is seen by the global public as someone on their side".
The fresh call to step down from one of Pachauri's one time allies on environment came even as UN's climate chief Yvo de Boer came out in his support, saying holding Pachauri responsible for the goof up in the world body's report on Himalayan glaciers would be "senseless".
The IPCC received the Nobel Peace prize not for its last report but all the work that has been done by the scientific community, Boer told reporters when asked if Pachauri should resign in the wake of controversy over report on Himalayan glaciers.
Pachauri has dismissed as "unfounded and baseless", claims that its findings on disappearing ice from the world's mountain peaks was based on a doctoral student's essay.
The IPCC credibility has come under attack in the past few days for picking a report that Himalayan glaciers will melt by 2035 from a science magazine without peer-reviewing it, a fault later admitted and regretted by the climate body.
