Today’s headline paraphrases slightly the title of a recent blog post by Bob Ward, who is Policy and Communications Director of the Centre for Climate Change Economics and Policy at the Grantham Research Institute. In that article Bob finally provides an answer to the question that’s been troubling us about how David Rose arrived at his preposterous “Almost a million more square miles of ocean covered with ice than at the same time last year” bullet point in his article published two weeks ago in the Mail on Sunday.

Mr. Rose never responded to any of my communications, but according to Bob:

Rose told me by e-mail that the source of his claim that the ice extent was 60 per cent higher this year was an announcement posted on the website of the United States National Snow and Ice Data Center on 4 September: “August 2013 ice extent was 2.38 million square kilometers (919,000 square miles) above the record low August extent in 2012.

The NSIDC confirmed to me yesterday that the main figure used by Rose for his article was mistyped and that the mistake was corrected on 10 September, showing that Arctic sea extent in August 2013 was only 29 per cent higher than was recorded for the same month last year.

In an email to me yesterday, Natasha Vizcarra, the media liaison for NSIDC, stated:

“When we published the report, it contained a typographical error in the difference between the August 2013 monthly ice extent and the record low August extent in 2012 (and the corresponding square mile conversions). If you subtract the August 2012 extent of 4.72 million square kilometres from the August 2013 extent of 6.09 million square kilometers, you get 1.38 million square kilometers, not 2.38 million square kilometers. Our readers noticed the error and we corrected the typographical error on September 10. There are no plans to make a statement on the change because it was not an error in the data.”

So it seems the raw data was correct, the graph displayed to the left of the “typographical error” on the NSIDC web site was correct, and yet the Mail’s “Arctic expert” David Rose and the thousands who have republished his assertions across the planet never cottoned on to the physical implausibilty of their headline “statistic”, and never bothered to contact the NSIDC to check?

What do you suppose is the probability that the rest of “the climate science” in Rose’s recent articles is similarly flawed? Here’s another bit of simple arithmetic he evidently managed to get wrong:

100 * 2.38 / 4.72 = 50.4%