The Rain in Spain

Erroneous geographical locations of precipitation proxies have been source of mild amusement to CA readers. Long ago, in connection with MBH, we observed that the rain in Maine fell mainly in the Seine – an error that Mann stubbornly refused to correct in Mann et al 2007 – not that any reviewer cared.

A few weeks ago, we observed with mild amusement that, as Liza Doolittle knew, the rain in Spain fell mainly in the plain – except that in Mann-world, it fell in the plains of Kenya.

Shortly afterwards, Mann reported the corrected the error without acknowledging the source – even though proper acknowledgment of sources is mandatory under Penn State codes of conduct.

I reported the error more as a matter of amusement, and this largely because of the prior history with the rain in Maine. But here’s something a little more substantial – Mann corrected the error and re-did his calculations. Below is a figure showing the impact of correcting the location of one proxy on his SH reconstruction. The difference in the 18th century is over half a degree, as shown below.


We sometimes are told that the various errors don’t “matter”. But here’s a case where merely changing the location of one proxy from Kenya to its correct location in Spain alters the estimate for the SH by about 0.5 deg C for an entire century. Oh yes, at the NAS panel hearings, Mann said that he knew the AD1000 temperature within 0.2 deg C.


  1. pjm
    Posted Nov 9, 2008 at 4:15 PM | Permalink

    He thought he knew. In theory there is no difference between theory and practice…

  2. anonymous
    Posted Nov 9, 2008 at 5:26 PM | Permalink

    So merely changing the location of one proxy can alter the reconstructed temperature for around a century by almost 1/2 a degree ? Positively miraculous.

  3. Mark_T
    Posted Nov 9, 2008 at 6:21 PM | Permalink

    Has anybody ever notified Penn state on Mann? I feel like writing them a letter detailing what he’s done.

    This is freaking ridiculous… I feel like we are being taken.

  4. Dishman
    Posted Nov 9, 2008 at 9:14 PM | Permalink

    Looking at the graph…
    I have to wonder why it only affected 1700-1800, plus or minus a few years.
    Within that span, it had a fairly large impact, but outside of it, it trails off to nothing.
    I thought that series was rather longer than that.

  5. Soronel Haetir
    Posted Nov 9, 2008 at 9:21 PM | Permalink

    It also amazes me that a precipitation record could have that great an impact on a temperature reconstruction. This record doesn’t even /claim/ to track temperature, unlike tree rings where the claim of temp vs precip limited can at least be made.

    • James Lane
      Posted Nov 9, 2008 at 10:11 PM | Permalink

      Re: Soronel Haetir (#5),

      Regardless of whether or not it’s a temperature proxy, I think the answer is alluded to in Steve’s previous post “A surprising result”. It seems that very few proxies are actually used in the SH reconstruction. So if you move one from the SH to the NH, it will have a big impact on the SH reconstruction, and (probably) little impact on the NH.

  6. John A
    Posted Nov 9, 2008 at 10:19 PM | Permalink

    Oh yes, at the NAS panel hearings, Mann said that he knew the AD1000 temperature within 0.2 deg C.

    This was another occasion where the sloppiness of the NAS Panel was evident. Mann gave a figure knowing full well that he would never be challenged to prove it.

  7. Miguel
    Posted Nov 10, 2008 at 1:39 AM | Permalink

    Just for your info. The error arised because in Spain we write 1.234,56 instead of 1,234.56 . Other difference when writing numbers is that our billion has 12 zeros, trillion 24 and so on.

  8. Phillip Bratby
    Posted Nov 10, 2008 at 1:40 AM | Permalink

    In my days working as a physicist/engineer and I found that the result of a published calculation was hugely sensitive to a small error, I would have been extremely concerned. I would have immediately notified my boss and an independent investigation would have been initiated to find out what went wrong (how the error was made and not spotted by reviewers, what the implications were etc) and to ensure that procedures were improved to minimise the possibility of this sort of error happening again.

    I wonder whatever happened to scientific integrity (not to mention personal integrity)?

    Still, what’s a small error when people’s careers and the future of the planet are at stake?

  9. Miguel
    Posted Nov 10, 2008 at 1:41 AM | Permalink

    Sorry, trillion has only 18 zeros, it is enough.

  10. UK John
    Posted Nov 10, 2008 at 2:38 AM | Permalink


    I reckon Mann uses a Bazillion, which has as many zeros as you need.

  11. trevor
    Posted Nov 10, 2008 at 4:11 AM | Permalink

    Re #10: Miguel. You sure about that? Looks to me like a million has 6 zeroes (1,000,000), a billion has 9 zeroes (1,000,000,000), and a trillion has 12 zeroes (1,000,000,000,000). You siding with Michael Mann? Or what?

    • Henry
      Posted Nov 10, 2008 at 4:39 AM | Permalink

      Re: trevor (#12), Miguel is (now) correct about the Spanish meaning of billion/billón and trillion/trillón. Kenyan use might be different.

      • pjm
        Posted Nov 10, 2008 at 4:20 PM | Permalink

        Re: Henry (#13), a billion in England officially means 12 zeros although in government papers it means 9, in most non-English languages I believe it means 12 zeros, In Australia it officially means 12 zeros, but usually means 9, and so on. I gather that in French the meaning has changed from 12 to 9 and back to 12 again. I personally (as an Australian Maths teacher) avoid using the word, and if I see it I know I don’t know what it means.

        • AndyL
          Posted Nov 10, 2008 at 5:12 PM | Permalink

          Re: pjm (#19),
          In England (and the rest of the UK) a billion universally means 9 zeros and a trillion means 12, not just in government papers. There is never any doubt about the meaning of the terms. The change from 12 / 18 zeros was about 20 years ago – at the time it was regarded as moving to US usage.

        • Peter Lloyd
          Posted Nov 11, 2008 at 1:51 PM | Permalink

          Re: pjm (#19),

          When I were nobbut a lad at school (65 yrs.ago!) I was taught that –

          10e6 = a million,
          10e9 = a thousand million
          10e12= a million million = a billion
          10e15= a thousand billon
          10e18= a million billion = a million million million = a trillion
          10e21= a thousand trillion
          10e24= a million trillion = a million million million million = a quadrillion.

          This was a logical, very practical, easily memorable system for naming very large numbers by using a million as the ‘base’. I was also told that it was the system used by scientists, engineers and my peers all over Europe.

          I was also told that Americans used “an inferior system” (!) based on the use of a thousand as the multiplier, i.e., a billion for one thousand million and a trillion for a thousand billion. However, I was not to bother with it because Americans only liked to say they were billionaires as soon as possible and couldn’t spell, either. (Sorry, guys, that’s just what I was told!). It was inferior because the range of numbers that could be readily expressed was more limited.

          However, from the 1950s on, the American system became adopted in England, first among the financial community, for obvious reasons – we had borrowed an awful lot of money from them and using their numbers saved a lot of argument about how much we still owed them. American companies started setting up in the UK, so scientists and technicians adopted US usage on a “can’t beat ’em, join ’em,” basis.

          I still think the European system is superior and that the Germans, French and Spanish are right to keep it, but I use the US system to avoid being widely misunderstood on both sides of the pond.

  12. SOM
    Posted Nov 10, 2008 at 5:26 AM | Permalink

    Has this been reflected in the GCM hindcasts yet?

  13. tty
    Posted Nov 10, 2008 at 10:32 AM | Permalink

    How do you even estimate temperature from precipitation? In Spain with a mediterranean climate I would guess that colder also means wetter, while in East Africa with a monsoonal climate it is probably the other way around.

  14. Richard deSousa
    Posted Nov 10, 2008 at 11:19 AM | Permalink

    Actually, the rain in Spain falls mainly in Galicia….

    • KevinUK
      Posted Nov 10, 2008 at 12:48 PM | Permalink

      Re: Richard deSousa (#16),

      Looks like your right R deS if the following is anything to go by

      Rain in Spain

      Kevin UK

      • Urederra
        Posted Nov 10, 2008 at 2:20 PM | Permalink

        Re: KevinUK (#17),

        Actually, the reference where the data is taken is: Rodrigo, F. S.; Esteban-Parra, M. J.; Pozo-Vázquez, D.; Castro-Díez, Y. 1999. A 500-year precipitation record in Southern Spain. International Journal of Climatology, vol. 19, Issue 11, pp.1233-1253

        And Galicia is in the Northern Spain. So, It would be more acurate (and funnier in my opinion) to say that “The rain in southern Spain fails mainly in Sierra Nevada”

        Yeah, the original Sierra Nevada is in Spain, for those who didn’t know. I don’t know if they are stripped bark Bristlecones in there. Or whether the trees in Sierra Nevada are a temperature or a CO2 concentration proxy but what It worries me the most is how rainfall can be a temperature proxy.

  15. Demesure
    Posted Nov 11, 2008 at 2:42 AM | Permalink

    Spanish meanings for billion & trillion are the same as in French and different than in North America.
    That’s why Old Europe is treated so badly by Mann: French river is relocated in Maine and Spanish station relocated in Kenya.

  16. Demesure
    Posted Nov 11, 2008 at 2:48 AM | Permalink

    In France, we use milliard for 9 zeros ( US billion) and pratically never “billion” (we say 1 thousand “milliard” instead). As to “trillion”, I don’t personnally have a billionnaire friend to hear it often.

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