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At a glance - What evidence is there for the hockey stick?

Posted on 21 March 2023 by John Mason, BaerbelW

On February 14, 2023 we announced our Rebuttal Update Project. This included an ask for feedback about the added "At a glance" section in the updated basic rebuttal versions. This weekly blog post series highlights this new section of one of the updated basic rebuttal versions and serves as a "bump" for our ask. This week features "What evidence is there for the hockey stick?". More will follow in the upcoming weeks. Please follow the Further Reading link at the bottom to read the full rebuttal and to join the discussion in the comment thread there.

At a glance

The Hockey Stick is a historic graph dating back to a paper published in 1999. It showed Northern Hemisphere temperature variations over the near-thousand year period from 1000-1998: the 'blade' of the stick represented the rapid warming of the late 20th Century. It has an iconic status, both in climate science and in the murky world of science-misinformation, where, naturally, it is despised by all and sundry.

Objections to the Hockey Stick are varied but mostly focussed on the stick's long handle and the data that represents. Obviously, during the centuries going back to 1000, reliable temperature measurements are not available. Fortunately for science, things that lived through that long time, such as certain very old trees, record in the rings of their wood an indication of temperatures, year on year. Gardeners and farmers talk about good and bad growing years and it’s the same for natural systems. For example, cold dry periods make for narrow and densely-packed tree-rings whereas warmer, wetter times lead to more widely-spaced ones.

Importantly, today there are a great many such past climate indicators, known as proxies because they act in place of thermometers. Because there's a range of indicators, the results from each one can be cross-checked against one another: if a new proxy is any good, its data should agree with that from the other, established ones

Proxy datasets contain more uncertainty than directly measured temperatures. Everyone knows that. That does not mean they are useless, far from it, because that aforementioned cross-checking means poor data can be readily identified and investigated. Finally, in the 24 years since the Hockey Stick graph was published, work on developing and refining the best proxies has been relentless: better, longer temperature reconstructions have become possible. And of course, global temperatures have continued to climb: in any of the observation-based datasets of surface temperature, all of the eight warmest years on record have occurred since 2015.

Please use this form to provide feedback about this new "at a glance" section. Read a more technical version via the link below!

Click for Further details

In case you'd like to explore more of our recently updated rebuttals, here are the links to all of them:

Myths with link to rebuttal Short URLs
Ice age predicted in the 1970s
It hasn't warmed since 1998
Antarctica is gaining ice
CRU emails suggest conspiracy
What evidence is there for the hockey stick
CO2 lags temperature
Climate's changed before
It's the sun
Temperature records are unreliable
The greenhouse effect and the 2nd law of thermodynamics

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Comments 1 to 6:

  1. Regarding the basic version of the rebuttal to the hockey stick is broken myth. This stated the myth at the top about Professor McKitrick and Steve McIntyres scepticism about the hockey stick, followed by a rebuttal. But IMO the rebuttal was a little bit vague and wordy, and didnt clearly say why McKitrick and McIntryes work was not relevant, and it wasnt clear on the fact that new studies done using different techniques supported the shape of Manns original hockey strick (the key point surely). In contrast the intermediate rebuttal was excellent.

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  2. nigelj @1

    Nigel - the actual rebuttal still has the fact and myth at the top of both the basic and intermediate versions. We didn't include these two boxes in the blog posts primarily intended to highlight the new "at a glance" sections and as reminders that we are interested in feedback about them.

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  3. BaerbelW @2.

    Ok. I will clarify. The  "at a glance" section for the basic hockey stick myth, and the information in  the further details both didn't seem that great for the reasons I stated above. I now see I should have replied by the special google feedback form. Sorry about that.

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  4. No need to apologide, Nigel. All feedback is good.

    I'll take another look at this. For at-a-glance, however, I felt that few completely lay readers would have ever heard of McIntyre or McKitrick; however their role in this could be brough in for Further Details. Often it's a case of choice whether to play the man or the ball, and that's not always easy: you have to weigh up how much prominence to give the actors.

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  5. John Mason @4, I get that, but you gave the actors quite a lot of prominence by highlighting them at the top of the page on the hockey stick is broken myth. And I believe this is the right thing to do because the entire myth is about their claims. So its impossible not to give them prominence.

    And its the first thing lay people read because its right at the top, so even if they haven't heard of these guys they know them now! But thats ok.

    And its not playing the man to criticise their findings, or put them in context (other studies using different methods found the same results.)

    Having correctly  given them prominence at the top of the page, I believe you have to  address what they say and why it lacks credibility in the at a glance section, or people will be confused. I was a bit confused. Of course it can be addressed briefly and expanded upon in the details, and further in the intermediate version.

    Its just a formatting thing. The actual content was is good.

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  6. In all fairness to me, Nigel, this was an early piece and I did not take the contents of the pre-existing "green box" into account sufficiently! I'll sort it.

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