The Hockey Stick and Climate Science

Posted Yesterday to the discussion at Climate Audit on the topic of “The Team Defends Paleo-Phrenology”

It may help …. to understand the nature of the science. It relies on statistical techniques to establish results. These, crucially, depend for their validity on the elimination of bias. If a researcher has faulty data, then the results are undermined. If the researcher is selective in the data, then the results are undermined. It outliers are not eliminated then the results are undermined. This all means that where there is extremely complex data, and problems of measurement, it is extremely difficult to establish conclusions that cannot be overturned. This is both true of economics and of paleoclimate.

I would contend that climate scientists, as a junior scientists, need to learn from other disciplines.
– From accountancy, about sense-checking the data (see link below)
– From research into new drugs, about the necessity for more technicians to collect and collate data, and to experiance dead-ends.
– From law, to distinguish between levels of evidence and distinguish baseless rhetoric from cogent arguement
– Most of all from statistical theory, where you will find you results will have no validity unless you take active steps to eliminate bias. Even then, with complex data, your results may still be later undermined, despite passing a battery of tests.

For all of these reasons, we should accept that the results of research are tentative. We should recognise the limits of our knowledge. In recognising the boundaries, and establishing procedures to quickly identify error, paleoclimate may be able to move forward.


The whole hockey stick issue, brought to a head with the Tamino posting, shows the problem of bias. To obtain a temperature reconstruction requires using data that usually gives a very weak signal indeed. Therefore any data needs to be carefully collected and every conceivable bias removed. It is only by eliminating bias that the statistical analysis can begin. In many cases there will be no significant results. Much painstaking work will achieve a dead end. And there is the rub. Careers are not made by failing to get a result. In this arena phenomenal fame and prestige can come to those who produce results that fortify the consensus. And there is plenty of recognition to those with supporting roles as well.

The original MBH98 may never have emerged in a more muted form if an expert reviewer had asked how such a novel result could be reconciled with the existing view that there was a medieval warm period. Hence my point about sense-checking in the previous blog posting. Similarly the comment that the 20th century warming was unprecedented should be answered with how do you know that? Read the Hockey Stick Illusion and you will find that the claim lacks scientific validity.  

If climate science it to mature it needs more painstaking data collection and analysis. As a science, it needs to find the current boundaries and limits of our current knowledge.

For those who believe that the Hockey Stick Team still have something worthwhile to say, should start with Steve McIntyres repost of “Tamino and the Magic Flute“. Compare that with Tamino’s posting “The Montford Delusion”.

Look at

1. Who gives the fullest answers?

2. Which side evades the points, or attempts sleight of hand?

3. How are contrary or neutral points treated. Clue – look at how Judith Curry (who is trying to remain neutral) is treated. Further, look at how contrary opinions are treated.

4. Finally who are the real deniers in all of this?

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  1. Tamino v. Montford – A Sense-Check « Manicbeancounter’s Weblog
  2. The Logic and Boundaries of Scepticism | ManicBeancounter

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