The United Nations' expert panel on climate change based claims about ice disappearing from the world's mountain tops on a student's dissertation and an article in a mountaineering magazine.
The revelation will cause fresh embarrassment for the Intergovernmental Panel on Climate Change (IPCC), which had to issue a humiliating apology earlier this month over inaccurate statements about global warming.
The IPCC's remit is to provide an authoritative assessment of scientific evidence on climate change.
In its most recent report, it stated that observed reductions in mountain ice in the Andes, Alps and Africa was being caused by global warming, citing two papers as the source of the information.
However, it can be revealed that one of the sources quoted was a feature article published in a popular magazine for climbers which was based on anecdotal evidence from mountaineers about the changes they were witnessing on the mountainsides around them.
The other was a dissertation written by a geography student, studying for the equivalent of a master's degree, at the University of Berne in Switzerland that quoted interviews with mountain guides in the Alps.
The revelations, uncovered by The Sunday Telegraph, have raised fresh questions about the quality of the information contained in the report, which was published in 2007.
It comes after officials for the panel were forced earlier this month to retract inaccurate claims in the IPCC's report about the melting of Himalayan glaciers.
Sceptics have seized upon the mistakes to cast doubt over the validity of the IPCC and have called for the panel to be disbanded.