The fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC) released in 2007 had said that at current rates of global warming, the Himalayan glaciers could disappear altogether by 2035.

“In drafting the paragraph in question, the clear and well-established standards of evidence, required by the IPCC procedures, were not applied properly,” the Geneva-based IPCC said in a statement today.

The agency said that the assessment referred to “poorly substantiated estimates of (the) rate of (glacier) recession and date for the disappearance of Himalayan glaciers”.

As reported by The Telegraph in November 2009, India’s environment ministry had released a report reflecting the views of several Indian glaciologists, essentially challenging the claim that most Himalayan glaciers would disappear by 2035.

The issue of Himalayan glaciers is the latest in a series of controversies scientists involved in climate change research have encountered in recent months. These include allegations that scientists were cooking up data and UK-based media reports questioning the business interests and financial earnings by IPCC chair Rajendra Pachauri, who is also the head of The Energy and Resources Institute, an Indian NGO.

Some Indian glaciologists say the IPCC’s faux pas on Himalayan glaciers shows that the agency’s authors had used non-substantiated information into a report widely believed to have been based exclusively on peer-reviewed science.

The 2035 date appears to have been based on a speculative comment by a single Indian glaciologist, Syed Hasnain, to a UK-based science magazine. The magazine reported the year without attempting to check whether the comment had passed peer review. The year was then picked up by other publications, and eventually found itself into the IPCC report.

Pachauri had told this newspaper earlier this week that the IPCC had allowed authors of the assessment report to include information from “non-published, non-peer-reviewed sources in IPCC reports”, through established procedures.

A lead author of the report said he and his collaborators had strictly followed the procedures. “We sent a draft of the report to all authors and to external scientific reviewers, and to representatives of more than 180 governments,” climate scientist and lead author Murari Lal said. “Nobody questioned it.”

However, the IPCC today stood by its report’s assertion that widespread glacier and snow cover loss in recent decades was expected to accelerate during the 21st century, reducing water availability, hydropower potential and river flows in the Hindu-Kush, Himalayan and Andes regions.

“This conclusion is robust, appropriate and entirely consistent with the underlying science and broader IPCC assessment,” it said.