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The money shot: where the hockey stick went wrong

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  • The money shot: where the hockey stick went wrong

    For many of those who follow the climate debate, the hockey stick is a litmus test.

    The hockey stick is the graph created by Michael Mann (and others) which purports to show that the historical temperature record as reconstructed via tree ring proxies (and a few others) shows an anomalous and inexorable increase in temperature.

    The hockey stick was then debunked by a blogger named Steve McIntyre who showed that the statistical techniques used to create the hockey stick graph were flawed in a number of respects - including errors of analysis, data modification routines which ignored polarity (i.e. turned data upside down), and undue focus on a very small subset of the tree proxies.

    Here is a graph of the data from the actual source scientist who compiled the Yamal tree data - one of the primary data sources for the Mann hockey stick:

    Notice the interesting part: the actual source data for Yamal diverges from what Mann and company came out with right about 1998.

    This is exactly the 'hide the decline' that was one outcome of the Climategate emails: that the hockey team (Mann and company) had arbitrarily cut off the tree proxy data because it diverged from the thesis of recent anthropogenic global warming.

    What do you call using parts of data which are useful but ignoring the rest?

  • #2
    Re: The money shot: where the hockey stick went wrong

    Close enough for government?


    • #3
      Re: The money shot: where the hockey stick went wrong

      Again, more old data, but worth repetition.

      Here are the records for the 10 trees used to reconstruct past temperatures - for which the above graph is the average of all of them. Notice how the post 1990 temperature 'spike' is seen in only 1 tree (YAD061), yet it is this tree's behavior which is 'reconstructed' in the Mann-ian hockey stick.

      It was already known that the Yamal series contained a preposterously small amount of data. This by itself raised many questions: Why did Briffa include only half the number of cores covering the balmy interval known as the Medieval Warm Period that another scientist, one with whom he was acquainted, had reported for Yamal? And why were there so few cores in Briffa’s 20th century? By 1988, there were only twelve cores used in a year, an amazingly small number from the period that should have provided the easiest data. By 1990, the count was only ten, and it dropped to just five in 1995. Without an explanation of how the strange sampling of the available data had been performed, the suspicion of cherry-picking became overwhelming, particularly since the sharp 20th-century uptick in the series was almost entirely due to a single tree.
      It is shenanigans like this which bring great suspicion on the scientific validity of the 'consensus'.


      • #4
        Re: The money shot: where the hockey stick went wrong

        dude, you are F***ing with people's religion here -- be careful!