Climate chief admits error over Himalayan glaciers

The head of the Intergovernmental Panel on Climate Change (IPCC) has been forced to apologise for including in its 2007 report the claim that there was a "very high" chance of glaciers disappearing from the Himalayas by 2035.

Rajendra Pachauri, the chairman of the IPCC, conceded yesterday that "the clear and well-established standards of evidence required by the IPCC procedures were not applied properly" when the claim was included in the 900-page assessment of the impacts of climate change.

The paragraph at issue reads: "Glaciers in the Himalaya are receding faster than in any other part of the world and, if the present rate continues, the likelihood of them disappearing by the year 2035 and perhaps sooner is very high."

Single source

The report's only cited source was a 2005 report by the environment group WWF, which in turn cited a 1999 article in New Scientist.

The New Scientist article quoted senior Indian glaciologist Syed Hasnain, the then vice-chancellor of Jawaharlal Nehru University in New Delhi, who was writing a report on the Himalayas for the International Commission for Snow and Ice. It said, on the basis of an interview with Hasnain, that his report "indicates that all the glaciers in the central and eastern Himalayas could disappear by 2035". The claim did not, however, appear in the commission's report, which was only made available late last year.

This week a group of geographers, headed by Graham Cogley of Trent University at Peterborough in Ontario, Canada, have written to the journal Science pointing out that the claim "requires a 25-fold greater loss rate from 1999 to 2035 than that estimated for 1960 to 1999. It conflicts with knowledge of glacier-climate relationships, and is wrong."

The geographers add that the claim has "captured the global imagination and has been repeated in good faith often, including recently by the IPCC's chairman". The IPCC's errors "could have been avoided had the norms of scientific publication, including peer review and concentration upon peer-reviewed work, been respected", they say.

Several of those involved in the IPCC review process did try to question the 2035 date before it was published by the IPCC. Among them was Georg Kaser, a glaciologist from the University of Innsbruck, Austria, and a lead author of another section of the IPCC report. "I scanned the almost final draft at the end of 2006 and came across the 2035 reference." Kaser queried the reference but believes it was too late in the day for it to be reassessed.

Publicly available IPCC archives of the review process show that during the formal review, the Japanese government also questioned the 2035 claim. It commented: "This seems to be a very important statement. What is the confidence level/certainty?" Soon afterwards, a reference to the WWF report was added to the final draft. But the statement otherwise went unchanged.

Grey literature

One of the IPCC authors, Stephen Schneider of Stanford University, California, this week defended the use of so-called "grey" literature in IPCC reports. He told New Scientist that it was not possible to include only peer-reviewed research because, particularly in the chapters discussing the regional impacts of climate change, "most of the literature is not up to that gold standard".

The Himalaya claim appeared in the regional chapter on Asia. "There are only a few authors in each region, so it narrows the base of science," Schneider says.

This week Hasnain has claimed, for the first time, that he was misquoted by New Scientist in 1999.