The attacks on climate science that were made ahead of the Copenhagen climate change summit were "organised" to undermine efforts to tackle global warming and mirror the earlier tactics of the tobacco industry, according to the vice-chair of the Intergovernmental Panel on Climate Change (IPCC).

In an interview with the Guardian, Prof Jean-Pascal van Ypersele admitted the IPCC had been "naïve and incompetent" in dealing with the false claim that all Himalayan glaciers could melt by 2035. He also accepted there "probably would be mistakes" in the even larger report due from the IPCC in 2013-14. But he emphasised that at a "difficult" plenary meeting in Korea earlier this month, the IPCC had immediately implemented some of the reforms recommended in a high-level independent report issued in August. He said the body would implement the rest of the reforms at the next meeting in May 2011, including a way to correct mistakes after publications and a future limit of one six-year term for the chair, currently Rajendra Pachauri.

"How could it simply be a coincidence that the 'climategate' emails are revealed two weeks before Copenhagen and that the mistake on the Himalayas is raised and transformed by some media into major error?" van Ypersele said. "I have a hard time imagining it could simply be a coincidence."

"I think some damage has been done unfortunately [to the IPCC's reputation]," and that this was what the "organised" critics wanted, he said. "Because if you don't have confidence in the scientific basis of the diagnosis that the planet's atmosphere receives too much greenhouse gas, why would any country or economic sector go through the difficulties of trying to reduce emissions."

"It is a very similar process to what the tobacco industry was doing 30 or 40 years ago, when they wanted to delay legislation, and that is the result of research – not my subjective evaluation – by Prof Naomi Oreskes and Erik Conway."

Oreskes, a science historian at the University of California San Diego, told the Guardian she agreed with Van Ypersele's that the attacks on climate science were organised: "Many of us were expecting something to happen in the run-up [to Copenhagen]. When it happened, the only thing that surprised me was that, compared with the events we documented in our book, the attacks had crossed the line into illegality."

The IPCC was poorly equipped to deal with the public relations crisis caused by the Himalayan mistake, according to Van Ypersele: "We were not prepared for this, we are all scientists, not specialists in disaster communication. We had to rely on the wisdom we had, which at the time was quite naïve and incompetent."

Pachauri, who has been heavily criticised by some media organisations, "had the courage to take a larger share of the responsibility" for the problems, said Van Ypersele. The IPCC structure did not allow for the responsibility for communication to be delegated and shared, he said, which "would have helped", but that would change with the new executive structure.

On the one-term limit for the chair, Van Ypersele said: "In general it is good for an institution to have new blood." But he said it would be a mistake to apply that in the middle of a term: Pachauri is currently serving his second term.