Reports indicate that Rajendra Pachauri, Chairman of the Intergovernmental Panel on Climate Change (IPCC) was informed that claims about melting Himalayan glaciers were false even before the Copenhagen summit.
According to a report in The Times, Dr Pachauri was told that the IPCC assessment that the glaciers would disappear by 2035 was wrong, but he waited two months to correct it.
The report says that he failed to act despite learning that several leading glaciologists had refuted the claim.
The IPCC's report underpinned the proposals at Copenhagen for drastic cuts in global emissions.
Dr Pachauri, who played a leading role at the summit, corrected the error last week after coming under media pressure.
He told The Times on January 22 that he had only known about the error for a few days.
"I became aware of this when it was reported in the media about ten days ago. Before that, it was really not made known. Nobody brought it to my attention. There were statements, but we never looked at this 2035 number," he had said.
Asked whether he had deliberately kept silent about the error to avoid embarrassment at Copenhagen, he had said, "That's ridiculous. It never came to my attention before the Copenhagen summit. It wasn't in the public sphere."
Dr Pachauri had previously dismissed a report by the Indian Government which said that glaciers might not be melting as much as had been feared.
He described the report, which did not mention the 2035 error, as "voodoo science".
However, a prominent science journalist said that he had asked Dr Pachauri about the 2035 error last November.
Pallava Bagla, who writes for Science journal, said he had asked Dr Pachauri about the error.
He said that Dr Pachauri had replied, "I don't have anything to add on glaciers."
Bagla said he had informed Dr Pachauri that Graham Cogley, a professor at Ontario Trent University and a leading glaciologist, had dismissed the 2035 date as being wrong by at least 300 years.
Professor Cogley believed the IPCC had misread the date in a 1996 report that said the glaciers could melt significantly by 2350.