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    But the observational estimate is not 1.33 C. See my reply to your earlier comment.

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    "A common perverse result is that tightening the fit to existing data (by adjusting the loose parameters of the model) can then worsen the extrapolations to the future." Indeed so. Over-fitting is a common problem and often a serious one.

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    Good,.so you have understood my question to be rhetorical and now you're countering (having conceded the point you earlier made). "Do proxies change the hockey stick". Who cares. Change it or not it doesn't matter, what matters is whether or not said proxies are fit for purpose. Do Mann's pine proxies appear fit for purpose? No they don't. Let me specify; if the purpose is to pressure policy based on pine proxies. No. Let's not defend the indefensible,. please Jim. Now let's look at proxy data with a wide viewing; like sat data, proxies have notoriously high error bands. We have to be aware of that fact. Some are better than others, and others are quite good in relation. We have to be therefore cautionary in making attribution claims concerning our theories. Do you agree? We have to properly reflect uncertainties.

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    Ragnaar As much as I appreciate Rud I can't see that he did what he claims in that post. He interprets the data in a way that disagrees with Salby but doesn't address the several first principal analyses that Salby uses to get to his conclusion. Salby's interpretation of the data is as valid as Rud's and if his physics is right his is correct. Rud's insistence that the pause falsifies Salby's case is in error as warming since the little ice age is likely the slow constant heat source driving the nearly constant increase in atmospheric CO2 that is not effected by changes in anthropogenic emissions rates.

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    Nic is there a chance of you/anyone producing your alternate version of Table 2 CMIP5- ESM above? It would be very helpful for we uneducated types to stare at and try and make sense of and hopefully become better informed. Just asking?

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    In answer to your question, "are you looking forward to a 700ppm world?" Again, who cares. I'm sorry to be so flippant. But seriously, Jim. To quote Happer, "nature has conducted the experiment." Jim, are planning to argue that nature hasn't dealt with this set of variables before. But you are just wrong. So don't bother wasting your time. Those proxies we were just talking about have also painted a picture of our last interglacial. And so we have validation for Happer's proposal. What we lack is validation for you proposal.

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    Atomsk: The idea that estimates of climate sensitivity from "energy balance models" should not be characterized as "observationally-base" is politically-motivated nonsense. TCR is defined as dT/dF, whether these values come from observations or AOGCMs. The technical definition defines dF as 1% per year, but everyone agrees that the slower observed rate of forcing increase is unimportant. Converting TCR into ECS is based on the law of conservation of energy, which is hardly a "model". The only assumption in energy balance models arises from internal (unforced) variability - chaos. In AOGCM experiments, trivially different initialization conditions result in different amounts of warming. The SPM for AR5 WG1 (p 17 Section D3) tells us: "The best estimate of the human-induced contribution to warming is similar to the observed warming over this period." "The contribution [to observed warming] ... from natural internal variability is likely to be in the range of −0.1°C to 0.1°C." If you believe the IPCC, observed warming differs little from forced warming. If AOGCMs are correct in their estimate of unforced variability, then their central estimates for climate sensitivity climate sensitivity are wrong. If AOGCMs are wrong about unforced variability, they are wrong. All observationally-based experiments involve some sort of model. Observations of the rate of sea level rise are based a statistical linear AR1 model for the noise in the data. Do you call those "model-based estimates of SLR"? Atomsk writes: "one can note that effective climate sensitivity for future CO2-induced warming is larger than effective climate sensitivity over the past century or so." Let's state this more accurately: The central estimates for modeled climate sensitivity are larger than observed climate sensitivity over the past century. SOME models predict a significant increase in climate sensitivity over the next century and some do not.

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    Sorry I meant Figure 2 NOT Table 2 in above comment.

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    Re: <b>"No. There is frequently, even mostly, culture and rhetoric upon both sides, yet their method has no theoretical underpinning and essentially relies on a trivial rhetoric analysis. As noted towards the end, even the authors later complained that the concept was being used by the ‘wrong’ side. Not surprising; it is so weak it allows anyone to call out any group as denialists. If you think that the critique is wrong, show your logic chain and specific points, with properly contexted quotes, as to exactly where and why."</b> You've messed up in your interpretation of the paper, and the core of your argument is epistemic relativism/subjectivism about science (a tedious, common trope among some people who do sociology of science). I've read the paper, and the other relevant paper on this that was also published in <i>BMJ</i>: <i>"How the growth of denialism undermines public health” “Denialism: what is it and how should scientists respond?”</i> I'll discuss them together, since they largely go together, have the same authors, and discuss similar issues. The paper lists characteristics of denialism. But the characteristics are more tactics that denialists use because of the predicament denialists are in. And what is that predicament? Getting around the weight of evidence against their position: <i>“A person who refuses to admit the truth of a concept or proposition that is supported by the majority of scientific or historical evidence.”</i> https://en.oxforddictionaries.com/definition/denialist <i>"How the growth of denialism undermines public health [...] It is, however, important not to confuse denialism with genuine scepticism, which is essential for scientific progress. Sceptics are willing to change their minds when confronted with new evidence; deniers are not."</i> So we can define denialists in relation to the evidence. And we can use denialist tactics as an (imperfect) proxy for denialism. Your objection to that boils down to claiming this isn't <i>objective</i>: https://judithcurry.com/2016/04/21/the-denialism-frame/ Sorry, but I'm a scientific realist/objectivist, so I'm not falling for that. The fact that some people disagree on a topic does not change the fact that there are right and wrong answers on that topic, and that there can be clear methods of reasoning to see who is right and wrong. For instance, many people still don't accept the scientific evidence on evolution. This disagreement is politically and religiously skewed (at least in the US), with political conservatives and very religious people being more likely to not accept the evidence on evolution. But this does stop us from knowing what the scientific evidence shows, and whose positions contradict the evidence. In science there are standard ways of inferring causation (ex: Bradford Hill criteria, Koch's postulates), reasoning about evidence (ex: inference to the best explanation, using predictive power, explanatory power, predictive scope), etc. We use these methods to guide us in scientific reasoning, and they work from topic to topic. They enable us, as a group, to overcome our biases and evaluate evidence in ways that might lead to conclusions we dislike, that make us feel uncomfortable, etc. So when I encounter a scientific topics where there is ideologically-skewing of views (ex: creationism/evolution, HPV vaccination, anthropogenic climate change, the health risks of smoking and second-hand smoking, etc.), there are methods I can use to see what the evidence shows. And I know those methods likely aren't skewed by ideological bias, since I also use them in topics in which ideological bias would not apply. I can vet them in those topics, and through philosophical/logical analysis. Heck, I can use the general form of the Bradford Hill criteria to argue that smoking causes cancer, HIV causes AIDS, vaccines cause autism, and increased CO2 caused most of the recent global warming. The following paper did something similar, by showing how one can recognize the silliness of denialists' reasoning by applying it to other topics: <i>"A blind expert test of contrarian claims about climate data"</i> Thus the presence of disagreement in the non-expert public, ideological bias, etc. does not prevent us from clearly knowing what the evidence shows, and thus knowing who the denialists are. If you want to claim otherwise, then enjoy the epistemic relativism/subjectivism on science. Your sociology of science isn't going to change the soundness of scientific reasoning and evidence. I'm familiar with how folks like Bruno Latour play that game. Re: <b>"That is absurd. You assert without examples (especially noteworthy in contrast to Andy West’s large collection of published examples), there there are prominent people who deny climate change, and climate change denier is well-defined? Possibly as something other than “denying climate change”."</b> You haven't shown that it's absurd. And you really did act as if you could simply read semantics from word structure. Hence you acting as if "climate change denier" means someone who denies that climate changes: <i>"Are there any examples of “climate change denier”, or is it a concept without any exemplars, or with few exemplars? I have not read any accounts denying warming or climate change"</i> https://judithcurry.com/2018/11/26/cagw-a-snarl-word/#comment-884999 That's on par with claiming that "Republicans" and "Democrats" must be arguing about a republic vs. a democracy as a form of government. It's as implausible as claiming that there are no "HIV/AIDS denialists", since no one denies that AIDS or HIV exists. Sorry, but you often cannot read a term's meaning off of word structure. So I suggest you stop doing that.

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    Hit those unthinking fasciasts with this: Have you ever seen actual evidence that man’s CO2 is causing serious global warming? Before you answer, please read this: --Evidence of warming IS NOT evidence that man's CO2 is the cause. --Warming is NOT evidence of its cause --Unusual weather occurrences are not evidence of its cause --Correlation is not causation --An expert’s assertion is not evidence. --Majority belief is not evidence --Government assertions are not evidence. --“What else could it be” is not evidence -- Polls are not evidence -- Climate models are not evidence

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    Your assumption was 64% for the historical period, so your BAU would also be 64% through to 1000 GtC. That's why showing the 1.05 C for just CO2 is not the full change, and you need to divide that by 0.64 to get the full change at 64% CO2.

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    I think we need a new award for university academics who get into serious trouble or preferably are fired, viz., The Kamikaze Academic of the Year award for anybody crazy enough to commit academic blasphemy. In fact we should start encouraging old academics who are near retirement to do their duty and commit academic suicide, by blasphemy, for the sake of our younger academics who cannot afford to take any risks. To be eligible for the KAotY award you would need to register your intention first. For those who get fired by Accident, like Cliff Mass perhaps (and me), one would only be eligible for the lesser AKAotY award. If you registered but Failed to get fired you would be eligible for the FKAotY award The magnitude of your failure would determine the prize, but you might be asked to try again and do it properly. So is anybody out there who is close to retirement and who is willing to make the sacrifice? You actually have a duty. We are all behind you. Just in case you're wondering, I am serious about this. I have a feeling crowd funding could be raised if we could get some of the big names who look at this blog interested Peter Ridd peterridd@yahoo.com.au FAotY candidate

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    They have error bars. The critics did not even change those. What to do next?

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    Modern man has not dealt with anything above 400 ppm before, so this is new territory. If you don't care about 700 ppm, you don't care about this whole debate, so why are you here? It's because you really do care.

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    And she bears the gifts of the Magi: she’s frank, incensed, and Mhyre…

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    Then I apologize Nic. Thank you for answering. MME=man-made emissions.

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    Jim, you're conflating 400ppm and 700ppm with some nebulous effect that you feel probably is bad. My caring is also not important to the thread or to the science. Of course you can produce several good studies which suggest this or that species will suffer under an increased carbon load or under a warmer canopy; however the net effect of increasing carbon is a boon for plant life, and a warming world will produce longer growing seasons. So more food and biodiversity.

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    Well, we can continue our scrutiny, and we can continue to weight proxies appropriately. The historical record is fuzzy. That is about it.

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    <i>then where did it all go? </i> Nick I have no more faith in carbon budgets than Trenberth's energy budget, so my opinion is most likely CO2 is improperly accounted for. Why shouldn't we believe GISS CO2 carbon budget isn't just tweaked like the GISS temperature series is tweaked?

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    On the contrary a lot of cities are planning for rising sea levels, and I would certainly encourage that. However planning for 2 or more meters is a lot harder than planning for less than one meter by 2100. Regarding Milankovitch, the relevant aspect is that it currently favors Greenland and Arctic sea ice, and we see that is not happening. Another factor has taken over. Milankovitch is slow and weak in comparison to what we're doing to the climate. The PAGES2k trend shows both effects.

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