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Scientific Consensus with Dr John Cook

Posted on 5 January 2024 by BaerbelW

There are so many misconceptions about consensus in science: What is a consensus? Does science work via consensus? To answer these and many other questions, Melanie Trecek-King - who runs the "Thinking is Power" website - talked with John Cook about the scientific consensus in general and about his study finding 97% consensus about human-cased climate change in particular.

Here are some relevant links to go along with the topics discussed:

Explainer: Scientific Consensus
The 97% Consensus on Global Warming
The Consensus Project
Cook et al. 2013


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Comments 1 to 3:

  1. Whilst it is reasurring that the information in the IPCC reports is reached ia consensus, it can gie us a false sense of security because only the most conservative estimates are included. The most alarming possibilities are left out because they are deemed unlikely. So the possibility of global temperatures reaching an insufferable 4 degrees higher is not something we should be concerned about because it is not very likely to happen.... until it does!

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  2. Ben Laycock @1

    I disagree that the IPCC only include the most conservative estimates of warming and SLR. Firstly the  most conservative estimates for warming are roughly 3.0 degrees C by 2100 at BAU (business as usual emissions) and on SLR are roughly 0.6 M this century. The IPCC sixth assesssment report also includes warming projections of up to 5 degrees C and and SLR projections of 1 - 2 metres this century ( which look very possible to me). So clearly the IPCC does not include only the "most conservative" estimates.

    You can google the IPCC reports. They are free to download.

    A small number of scientists like James Hansen have written studies with higher estimates of warming and SLR but they are not included as the IPCC presumably decided the science was not quite convincing enough. The IPCCs job is to review all the science and decide which is most credible. That also includes reviewing studies claiming the planet is about to enter a long cooling period. They dont include those because they lack any credibility.

    However IMO the Summary for Policymakers could do a better job of highlighting the worst case scenarios and their implications.

    Its true the IPCC do lean a little bit conservative on the science generally. However this is how science has worked for decades and its to help avoid mistakes and loss of credibility. It may be frustrating at times but the alternative sounds worse to me. Policy makers also presumably realise there is a certain conservative leaning or reticence and take that into account.

    And remember there is nothing reassuring about SLR projections of up to 2 metres this century. This is obviously very serious and if anyone can't figure that out I doubt that a higher estimate of 3 metres would make much difference to them. 

    I agree that we have to be cautious interpreting the meaning of low possibility high impact events like 5 degrees warming this century or 2.0M SLR. Firstly as you say they can still happen. Secondly they are assigned a low possibility of occurence but that is probably a "conservative" leaning evaluation or probability. Thirdly the impacts are so incredibly serious that even although the possibility is low we need extreme caution and should therefore be mitigating the climate problem. There are many activities that have a low possibility of harm but very serious outcomes, that sensible people avoid like driving on worn tires that are just slightly below warrent of fitness standards.

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  3. Ben@1 and nigelj@2, I tend to agree with both of you, but would defer to someone with deeper knowledge of the IPCC than I have.

    My understanding is that Ben is correct in terms of historical IPCC predictions, but that Nigel is correct in terms of the latest report, which now does include more extreme predictions than previously included.

    But the other message that I keep hearing in videos and reading in text is that the climate is responding/changing faster than many climate scientists expected, and by my reading, this sentiment is not refleccted in the IPCC reports.

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