Last week, George Monbiot wrote a fascinating column in the Guardian. It opened thus:

On April 16, New Scientist published a letter from the famous botanist David Bellamy. Many of the world’s glaciers, he claimed, “are not shrinking but in fact are growing … 555 of all the 625 glaciers under observation by the World Glacier Monitoring Service in Zurich, Switzerland, have been growing since 1980”. His letter was instantly taken up by climate change deniers. And it began to worry me. What if Bellamy was right?

So he telephoned the World Glacier Monitoring Service and read out Bellamy’s letter to them.

I don’t think the response would have been published in Nature, but it had the scientific virtue of clarity: “This is complete bullshit.” A few hours later, they sent me an email: “Despite his scientific reputation, he makes all the mistakes that are possible.” He had cited data that was simply false, he had failed to provide references, he had completely misunderstood the scientific context and neglected current scientific literature. The latest studies show unequivocally that most of the world’s glaciers are retreating.

So where had Bellamy got his numbers from? Read George’s article for the grisly details, but the answer, in a nutshell, is that they came from websites published by a number of fruitcakes who are into denial about global warming. The article is a salutary warning to anyone who believes something on the grounds that they saw it on the Net. It should be required reading for every teacher who tells pupils to “look it up on the Web”.