Climate stories are arriving thick and fast in the wake of Climategate, but the tale of the Himalayan glacier meltdown that never was must be one of the most strange and interesting of them all.
It's a tale that provides an insight into the "certainties" the political and media elites have come to depend on - and how badly the "scientists" have let them down.
In its Fourth Assessment Report in 2007, the UN's climate change panel the IPCC reported that the Himalaya's glaciers might disappear completely by 2035. It made the prediction on this page, where it proudly stands intact today. The IPCC also noted that the Ganges basin is home to half a billion people, leading us to infer that the loss of the largest ice mass outside the Arctic would be catastrophic.
The Himalayas are home to 15,000 glaciers, many of which are a kilometre thick. Dramatising this disappearance would tax the producers of any disaster movie; yet this, we were told, could be a reality in our lifetimes, the IPCC reckoned. On current trends, four-fifths would melt.
Remember that the IPCC doesn't do research of its own - it is obliged to report the "state of the science" - meaning that the reports should err on the side of caution, and the panel is not supposed to make policy recommendations. That's the theory, anyway - the IPCC rarely misses the opportunity to tell us that "2,500 scientists" are involved in the process - and this process generates that elusive hallmark of Truthiness, a "scientific consensus".
What could possibly go wrong?
It now turns out the 2035 claim has no scientific basis at all - but was an off-the-cuff remark by an obscure Indian scientist who now disowns the prediction. It was made not in the scientific literature, but a telephone interview with a pro-warming journalist Fred Pearce of the New Scientist for a news item in the magazine in 1999. The IPCC picked up the spurious factoid after it was cited in a propaganda publication by eco-group the World Wildlife Fund. (WWF).
And now the IPCC editor responsible for the chapter sheepishly admits he doesn't know anything about glaciers.
"I am not an expert on glaciers.and I have not visited the region," says Murari Lal, "so I have to rely on credible published research". Which, you'll note, he failed to do.
But his justification is intriguing. Note how observation and physical sciences had become secondary to the power of personal reputation - or more accurately, perceived reputation:
"The comments in the WWF report were made by a respected Indian scientist and it was reasonable to assume he knew what he was talking about," Lal said.
Lal may as well have said the Himalayan glaciers would disappear "because some bloke said so".
Many glacier experts rubbished the claim - even in warm times glaciers retreat by inches, yet the typical glacier is 300 feet thick. All 15,000 would need to melt in short order for the IPCC's prediction to come about.
Yet it has taken three years to debunk the claim - and it's six months since India's environment minister put the issue on the international agenda.