Humiliating Mistakes by David Rose

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%

3 thoughts on “Humiliating Mistakes by David Rose

  1. Haha its really embarassing and really proves how little educated this David Rose guy is. When you write a story about science you at least have to double check your numbers.

    I still wonder how he got that 60% though – as its 10% higher than even the calculation from the mistake. I guess 50% didn’t sound serious enough but 60% would be his sure sign of recovery.

    An interesting thing though is that when the ice extent is down into 0.5 square kilometers we can be sure that if the year after have 1.0 square kilometers he will report 100% recovery (assuming he gets his calculations right this time)… as if its back to normal… haha.

    I guess a better figure to report to people is how far off the average the extent is – and ofc at the same time say something about volume which is really low still.

  2. John – “Volume which is really low still”

    Quite so! Rose actually doesn’t say which metric he is referring to in his original article, although the caption under one of the graphics does mention “extent”. The email exchange mentioned by Bob Ward does however suggest he was basing his claims on NSIDC extent.

    When talking about the “amount” of sea ice volume is obviously the relevant metric, to anyone who has studied a modicum of physics at least!

  3. Its also odd to talk about extent and recovery before the actual minimum is reached. It just showed that they were in hurry to get some story out before too much focus was shifted to the IPCC report. Also much of the ice when the minimum was reached was rather slushy, and if you had packed it together I guess real actual extent would be quite a bit lower. Still with the fact that volume is still low we basically have spread the ice mass over a thinner area that is bigger than last years record low (and even 80% of scientists at Bjerknes predicted extent would be bigger this year as 2012 was clearly an exceptional anomaly – although still showing the clear trend of melting).

    Perhaps Rose used a drafting compass from the pole to the point where the extent was furthest from the pole and used that radius to calculate extent? :) – The kind of number magic these anti-science groups conjures up never cease to amaze with WUWT being a prime showcase for any oddball theory you can come up with in opposition to the settled science.

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