But it now appears that the estimate about Himalayan glacial melt was based on a decade-old interview of one climate scientist in a science magazine, The New Scientist, and that hard scientific evidence to support that figure is lacking. The scientist, Dr. Syed Hasnain, a glacier specialist with the government of the Indian state of Sikkim and currently a fellow at the TERI research institute in Delhi, said in an e-mail message that he was “misquoted” about the 2035 estimate in The New Scientist article. He has more recently said that his research suggests that only small glaciers could disappear entirely.

The panel, which relies on contributions from hundreds of scientists, is considering whether to amend the estimate or remove it.

“The I.P.C.C. considers this a very serious issue and we’re working very hard to set the record straight as soon as we can,” said Christopher Field, co-chairman of the panel’s section that was responsible for the report, which deals with impacts, adaptation and vulnerability.

He noted that the potentially erroneous figure in question had appeared only in the panel’s full report of more than 1,000 pages and had been omitted in later summary documents that the panel produced to guide policy. The summaries said only that the Himalayan glaciers “could decay at very rapid rates” if warming continued. Such documents are produced after panel members review a full-length report, although if a figure in the report is deemed to be in error, it is supposed to be removed.

Still, the revelation is the latest in a string of events that climate change skeptics have seized on to support their contention that fears about warming are unfounded, or at least overblown. Late last year, hackers obtained private e-mail messages from leading researchers at the University of East Anglia in England suggesting they were altering the presentation of some data in a way that emphasized the human influence on climate change.