The chairman of the leading climate change watchdog was informed that claims about melting Himalayan glaciers were false before the Copenhagen summit, The Times has learnt.

Rajendra Pachauri was told that the Intergovernmental Panel on Climate Change assessment that the glaciers would disappear by 2035 was wrong, but he waited two months to correct it. He failed to act despite learning that the claim had been refuted by several leading glaciologists.

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. He said: “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.”