Wall Street Journal, Dec. 10, 2005

The Wall Street Journal mentioned us editorially yesterday here . While it’s nice to be mentioned, they incorrectly say the following:

The Canadians found that the Medieval warm period had indeed occurred, suggesting that periods of warming and cooling were natural trends unrelated to the number of SUVs on the road.

Readers of this blog know that we made no such claim about the MWP. We have repeatedly made it clear that we offer no alternative reconstruction of past climate. We merely demonstrated many flaws in the data and methods of MBH and stated that MBH claims that their reconstruction demonstrated 20th century uniqueness with robustness and statistical skill were invalid – a different and more nuanced assertion than attributed to us by WSJ.


  1. Ross McKitrick
    Posted Dec 12, 2005 at 9:55 AM | Permalink

    Since the WSJ cite the 2003 paper, it’s worth quoting our conclusions from it: “Without endorsing the MBH98 methodology or choice of source data, we were able to apply the MBH98 methodology to a database with improved quality control and found that their own method, carefully applied to their own intended source data, yielded a Northern Hemisphere temperature index in which the late 20th century is unexceptional compared to the preceding centuries, displaying neither unusually high mean values nor variability. More generally, the extent of errors and defects in the MBH98 data means that the indexes computed from it are unreliable and cannot be used for comparisons between the current climate and that of past centuries, including claims like “temperatures in the latter half of the 20th century were unprecedented,” and “even the warmer intervals in the reconstruction pale in comparison with mid-to-late 20th-century temperatures” (see press release accompanying Mann et al 1999), or that the 1990s was “likely the warmest decade” and 1998 the “warmest year” of the millennium (IPCC 2001).”

    I think these conclusions have stood up well.

  2. Steve Latham
    Posted Dec 12, 2005 at 7:52 PM | Permalink

    Have you guys written a letter to the editor correcting the error?

  3. Steve Latham
    Posted Dec 15, 2005 at 12:52 PM | Permalink

    This thread doesn’t seem to have spawned much interest. But why haven’t you done a reconstruction? It seems you have all the tools. Maybe you’ve described your reasoning elsewhere….

  4. Steve McIntyre
    Posted Dec 15, 2005 at 1:07 PM | Permalink

    I have sufficient tools to do the sort of thing that the Hockey Team does. It would be possible for me to cherry pick some squiggly proxies, average them together and call it a reconstruction. With a little application, I could cherry pick series which gave a plausible RE statistic. I could even add some bells and whistles with wavelets or something like. I’m sure that I can pick series that would yield a higher MWP than modern or the reverse. But what are these things really? I’m not sure what meaning any of them have. I agree with Burger and Cubasch that it may not be possible to salvage anything from the present line of multiproxy studies.

  5. Ross McKitrick
    Posted Dec 15, 2005 at 1:59 PM | Permalink

    Re #2. Good point Steve. I just sent one in.

  6. Steve Latham
    Posted Dec 16, 2005 at 8:42 PM | Permalink

    Hi Ross, that’s great (#5). I’m sorry to hear that you and Steve M won’t generate what you consider a best reconstruction (#4). Even just going back 500 years it could perhaps be of some use. But if it’s impossible to salvage anything useful from the multi-proxies, that leaves us with a very large “What’s next?”

  7. TCO
    Posted Dec 16, 2005 at 9:01 PM | Permalink

    I think the temp rise over the same period as the CO2 rise is rather suggestive of GW.

  8. Ross McKitrick
    Posted Dec 17, 2005 at 10:43 AM | Permalink

    (#6) One of my profs in grad school was part of a team that published a pretty inescapable critique of a popular technique of cost-benefit analysis. They showed that the interpretation being applied to price data implied an underlying model of consumer behaviour that we knew on other grounds was not true. But they didn’t have any alternative to suggest. I asked him, so why don’t you guys come up with a better method for CBA? His answer was: Hercules’ job was to clean out the Augean stables, not fill them back up. It was an amusing answer, though I found it a bit annoying, and I understand why people would find our unwillingness to do our own recon equally unsatisfying. But in the murkier branches of CBA one does get to the point where you ask, Is some number worse than no number? It is sometimes more truthful to simply say, there are no solid numbers and you’ll have to make a decision in the context of that much uncertainty, rather than wave your wand and pretend you have a quantitative basis. For what it’s worth, that’s my view of the situation for these millennial climate histories.

  9. Steve McIntyre
    Posted Dec 20, 2005 at 10:15 PM | Permalink

    Re #5: Ross’ letter has been accepted by the WSJ and will run on Friday. I’ll update then.

  10. Steve McIntyre
    Posted Dec 24, 2005 at 11:21 AM | Permalink

    Ross sent the following letter which was scheduled for publication by WSJ on yesterday. I haven’t verified the final version as printed.

    Dear Sir
    In an Editorial (December 10), you described some work I coauthored with Stephen McIntyre, which showed the IPCC’s ‘hockey stick’ graph to be statistically flawed. While I concur that this finding is relevant for understanding the weakness of the science behind of Kyoto, I would like to correct one thing. You said we “found that the Medieval warm period had indeed occurred.” We have not said this. What we showed is that the hockey stick does not support the conclusion that the late 20th century climate is unusually warm, or that contemporary climatic changes are outside the bounds of natural variability, in comparison to the past millennium. As a statistical model it is simply uninformative on these questions, something the IPCC would have discovered themselves if they had independently checked it before building their report around it.
    Yours truly

    Ross McKitrick”

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