Claims that Himalayan glaciers could vanish by 2035 because of climate change have been shown to be untrue.

The chief of the UN’s Intergovernmental Panel on Climate Change (IPCC), Rajendra Pachauri, has admitted such claims were “an error” but said the threat posed by climate change could not be ignored.

Mr Pachauri said there was no hard science to back the “regrettable” claim that Himalayan glaciers could disappear within three decade if global warming goes unchecked.

Less than three years ago the IPCC published a wide-ranging report advising governments on how to deal with global warming issues. Part of the report stated: “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 if the Earth keeps warming at the current rate.”

But now it appears such speculation was taken from an interview in a 1999 issue of the New Scientist magazine with Indian glaciologist Syed Hasnain. The claim was never repeated in any peer-reviewed literature but was picked up in a campaigning report by WWF, the environmental group, which was the source for the inclusion of the claim by the IPCC. Hasnain has since admitted that the claim was “speculation” and was not supported by any formal research. Lat week the IPCC issued a statement admitting that the estimates on glacier retreat were “poorly substantiated”, but went on to say that global warming will lead to significant losses in glacier mass, resulting in water shortages.

This latest revelation follows the so-called “climate-gate” scandal where British scientists apparently tried to prevent other researchers from accessing key date. And last week suggestions that sea levels were likely to rise 1.9m by 2100 were criticised by the Met Office, who said much lower levels were more likely.