by Agence France-Presse
GENEVA – An estimate on the fate of Himalayan glaciers that featured a benchmark report on global warming has been “poorly substantiated” and represents a lapse in standards, U.N.‘s climate scientists said on Wednesday.
Charges that the reference was highly inaccurate or overblown have stoked pressure on the Intergovernmental Panel on Climate Change (IPCC), already assailed in a separate affair involving hacked email exchanges.
The new row focuses on a paragraph in the IPCC’s Fourth Assessment Report in 2007, a 938-page triple-volume opus that warned climate change was on the march and spurred politicians around the world to promise to take action. In the contested section, the report declared that the probability of glaciers in the Himalayas “disappearing by the year 2035 and perhaps sooner is very high.”
The IPCC said in a statement that the paragraph “refers to poorly substantiated rates of recession and date for the disappearance of Himalayan glaciers. In drafting the paragraph in question, the clear and well-established standards of evidence, required by the IPCC procedures, were not applied properly.”
It added: “The Chair, Vice-Chair, and Co-Chairs of the IPCC regret the poor application of well-established IPCC procedures in this instance. This episode demonstrates that the quality of the assessment depends on absolute adherence to the IPCC standards, including thorough review of ‘the quality and validity of each source before incorporating results from the source in an IPCC report.’”
The statement noted that the reference was not repeated in an important “synthesis report” of the 2007 assessment, and stressed the IPCC’s “strong commitment” to thorough, accurate review of scientific data.
The IPCC shared the 2007 Nobel Peace Prize for its reputation of scientific rigor, caution, and fact-checking. Under this process, data are peer-reviewed by other scientists and are then meant to be double-checked by editors.
On Monday, a leading Austrian glaciologist, Georg Kaser, who contributed to the 2007 report, described the mistake with the 2035 date as huge and said he had notified his colleagues of it months before publication.
Despite the controversy, the IPCC on Wednesday stood by the overall conclusions about glacier loss this century in major mountain ranges, including the Himalayas. “This conclusion is robust, appropriate, and entirely consistent with the underlying science and the broader IPCC assessment,” it said.
The report concluded that “widespread mass losses from glaciers and reductions in snow cover over recent decades are projected to accelerate throughout the 21st century.”
This would reduce “water availability, hydropower potential, and changing seasonality of flows in regions supplied by meltwater from major mountain ranges (e.g. Hindu-Kush, Himalaya, Andes), where more than one-sixth of the world population currently lives,” it added.
The Indian scientist at the centre of the row, Syed Hasnain, has denied that he mentioned the 2035 date in a magazine interview more than 10 years ago, the apparent original source for the prediction.
IPCC Chair Rajendra Pachauri on Tuesday defended the panel’s work, a position shared by other scientists, who say the Fourth Assessment Report’s core conclusions about climate change are inconvertible. “Theoretically, let’s say we slipped up on one number, I don’t think it takes anything away from the overwhelming scientific evidence of what’s happening with the climate of this Earth,” Pachauri said.
Skeptics have already attacked the panel over so-called “Climategate,” entailing stolen email exchanges among IPCC experts, which they say reflected attempts to skew the evidence for global warming.
The row came as the U.N. panel began the marathon process of drafting its Fifth Assessment Reports, inviting nominations of scientists to lead its work.
The reports, due out in 2013 and 2014, will focus on sea-level changes and the influence of periodic climate patterns like the monsoon season and El Niño, and will aim to forge a more precise picture of the regional effects of climate change.
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