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This is a great series, starting with actual definitions for climate (my only quibble if that one must choose an area as well as time period to do the statistical work). I clicked through to the actual IPCC material but, once again, find I haven't the background to understand it. So, one more request for your help. You note the IPCC's conclusion that temperature changes (global or regional?) do show high confidence in attribution to human causes but I realize I don't know: which temperature readings (where/when) are being compared to which temperature readings (where/when) and what the timing of intrinsic variability is. Can you help? I am one of the right age to remember when this whole thing was called global warming . . . so the temperature issues do concern me. Also, if you could address in a bit more detail how the global association ever arrived at 30 years of statistics for doing their 'climate' calculations, that would be good to know. You are my trusted source for these questions! Please, keep up what you're doing. The population desperately needs someone to translate the IPCC information neutrally.

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I have already asked one question, but I have another. At lest the media I hear from, say things like "CO2 accumulation since ~1850 has made events like this [wildfire, etc.] N% more likely." That statement does not seem to be in conflict with "According to the IPCC, we cannot in fact simply “look out the widow” and observe climate change — even for video-friendly hurricanes, floods, and drought."

To the untrained ear, the first sounds like the probability is a bit more that 50/50 and the seconds sound like the probability is less than 1 in 20 (or whatever the confidence level) which is not a contradiction. Is my "untrained ear" hearing correctly? OTOH if there is a contradiction, is the media source just wrong; N = 0?

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To my ear, the only plausible interpretation of a claim that something has become "N% more likely" is that its expected frequency has increased by N%. Unless you interpret "look out the window" as taking a snapshot rather than a movie, this does appear to conflict with the IPCC assertion - so long as the movie is long enough (depending on N) to capture enough expected examples for an undercount to be statistically significant (which I am guessing is what you mean by the "1 in 20"). But I do not understand how even the "untrained" ear could hear "N% more likely" as "a bit more that 50/50" (or even what that would be intended to mean).

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author

Great Q

And one I'll be discussing in a soon-coming post

Here is the nub of the issue, which gets back to the discussion in part 1 of this series:

1. Let's assume that "CO2 accumulation since ~1850 has made events like this [wildfire, etc.] N% more likely"

2. That is from a statistical standpoint the same as saying "Adding an ace to a 6-deck blackjack deck makes two-card hands with aces N% more likely"

3. If we play a series of hands, then at some point we will start gaining confidence that the deck is indeed stacked -- the more hands the greater the confidence.

4. With respect to many extreme events (e.g., hurricanes, floods, drought) we have not yet seen evidence at even medium confidence (50%) to suggest trends outside the bounds of historical variability.

5. To claim that something is more likely means that there should be an observable trend. If there is no trend than that means that the N% increase must be small in the context of variability. N% may not be zero, but in the absence of an observable trend (esp since 1850) N% must be very, very small compared to variability.

6. This is consistent with IPCC projections that for most phenomena N% trends won't be detectable with even medium confidence under extreme emissions scenarios to 2100.

So the media's claim of detection is indeed problematic, and we haven't even started discussing attribution.

Does this make sense?

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It does. It is what I was getting at in asking about the difference between slightly more that 50/50 vs 1/20.

It is the way I understand your positions

a) that we cannot reject the null hypothesis of no effect of CO2 accumulation on extreme weather events and

b) that, based on physical-economic modeling of the effects of CO2 on a huge range of planetary systems (and not excluding extreme weather events), it is worthwhile to make some amount of effort to reduce the emission of net CO2 going into the atmosphere and..

c) a corollary of b), getting the modelling wrong by overestimating the physical effects and hence the economic costs of CO2 accumulation would lead to making too much, too costly effort to reduce net CO2 emissions.

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Jul 25Liked by Roger Pielke Jr.

Roger: Regarding AR6 Table 12.12, how do their high and medium confidence levels relate to their S/N>1 detection threshold? How do we view this in terms of probability, when there are 2 probabilities assigned to what appears to be a 50% likelihood threshold?

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The IPCC is not always consistent in how it uses likelihoods, confidences, and significances. The S/N thresholds are not commonly used and more rarely associated with a confidence finding. There is also considerable variation across chapters. Plenty of room for improvement here.

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Jul 24Liked by Roger Pielke Jr.

Good, as always! Roger, can you point me to where you explained the differences between the approach of WG1 and WG2? I'm sure you've covered it (and I've probably read it) but you have a lot of posts!

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Jul 24·edited Jul 24Liked by Roger Pielke Jr.

Thank you. I avoid X/Twitter as much as possible. But I'll check these out. (That was a fast reply!)

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The World Weather Attribution organization was promoted in Canada's leading newspaper (Globe and Mail - editorial July 27). They claim they can do rapid attribution to recent events. I had to dig deep to try to understand their methodology, which includes modeling (which makes me very nervous).

Can you offer comments in a future article about how to decipher these types of organizations that promote recent events to Climate Change.. and who is funding them?

PS...great series on attribution. very interesting.

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How else except modeling could one make a statement about whether past accumulation of CO2 in the atmosphere had made an event more like than not? How else do you have a counterfactual with which to contrast the even in question.

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The new table is a lot easier to present. Thanks. This has always been a brainwashing and human nature study, not science. They should stick to real science like children being born in the wrong body. That is tongue in cheek for any wokesters reading this.

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I'd like to understand better the importance of emergence and attribution. Correct me if I am misstating what your are saying.

Climate science has identified certain changes in physical systems - melting glaciers, CO2 concentration in the ocean, global temperature, etc. -- which are consistent with the results of climate models of the effects of actual CO2 accumulation in the atmosphere? These observations are inconsistent with those models when run with no change in CO2 accumulation?

"Weather" events -- hurricanes, wildfires, floods, etc. -- are different? They are so variable that there is little difference in what we would expect between actual changes and no changes in CO2 concentration? We might well have observed recent numbers and intensities of fires, floods, etc., even if there had been no increase in CO2 accumulation?

Model predictions of the mean harm from the further accumulation of CO2 in the atmosphere (at least those based on weather everts) are very uncertain? In Bayesian terms, today's wildfire should lead to an imperceptible increase in one's credence that CO2 accumulation is harmful?

[I did read your Dad's explanation as helping to explain the reasons for the great difficulty in detecting the effects of CO2 accumulation on weather.]

As with all my questions about your posts, it all comes back to what does it mean for policy.

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Assuming the politicians are correct, we should all be asking our leaders (every country) for adaptabilty solutions in parallel with the "change the entire temperature of the Earth despite China doing nothing" . Better practical practices in agriculture, food, water, energy, air conditioning, heat, healthcare, hurricanes, floods, draughts, etc. to protect people? At least demand that our leaders do these things while running in CO2 net zero circles yelling "the sky heating up". Do they really want people to live better and longer lives?

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It seems to me that we should be investing more in adaption, whether or not the extremes weather events we see are the result of past accumulatio of CO2 in the atmosphere or indeed there has been a change in event frequencies. If we think events are increasing in frequency, again, for whatever reason, that would affect the kind and levels of investment in adaption.

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Excellent post, sir. Thank you. As usual, I have a couple of questions:

1. The most disturbing statement in your essay was, "The fact that this gap is encouraged and reinforced by many who profess climate expertise makes this issue truly unique among issues where science meets policy and politics." Why does the scientific community encourage such aberrant behavior? I know you've been writing about this off and and on for the past several years; has time given you insight as to why we allow crap like this to occur? Is research funding so important it supersedes objectivity, truth, and common decency? (I'm speaking about the continued use of the term "denier.")

2. That said, I am curious as to your review/opinion of the paper by May and Crok found at https://onlinelibrary.wiley.com/doi/10.1111/ajes.12579. This paper was published at the end of May this year by Wiley, and seems to support your thesis that "emergency" has been overstated. They go on to state that since "the current climate is arguably better than the pre-industrial climate and we have observed no increase in extreme weather or climate mortality, we conclude that we can plan to adapt to any future changes." They also argue there is no need to end fossil fuel use.

Thank you for your work.

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But "plan to adapt" still implies changes, just that adaption is more cost effective than mitigation.

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That is very true, sir, thank you. Key words - "cost effective." Something I've always wondered about - in essence, humans have been adapting to climate since they first wore bear skins and moved into caves. I've heard many alarmists cry out that "adaption" isn't enough, and can't be the answer. Seems like its worked for the past hundred thousand years or so...can't argue with success.

I've also read enough of May and Crok independently to know they argue that climate change is constant and evident from the record. Andy May has written that the climate debate "is not whether humans influence the climate, the debate is over how much we contribute and whether the additional warming is dangerous." He goes on to argue that "human efforts to 'fight' climate change will be fruitless. The climate will do what it wants, and when it wants. Human efforts must be focused on identifying long-term change, and developing measures to protect humans from the extremes of those changes."

This was a paper that goes beyond what Dr. Pielke has advocated, and I was (am) curious about his take on their arguments.

Anyway, thanks for your comment, and yes, change is unavoidable.

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Clearly if we have no ability to affect the variables that are causing climate change, then we should not invest any effort in trying to affect them. But equally clearly, we CAN affect the amount of CO2 emitted, so this implies that CO2 accumulation in the atmosphere has no effect on the climate. But I do not think that is Roger's claim.

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There are a number of scientists (Lindzen, Happer, Soon, among them) who are argue along with Crok and May that carbon is not a problem. You're right, I don't think Dr. Pielke agrees with that, though I believe he is by no means an alarmist. Personally, I look at carbon more specifically: coal. There are good reasons to move away from coal - it's waste, the costs to scrub emissions (NOx, SOx), it's transportation. Gas makes more sense from the emissions and overall cost perspective. I am no climate scientist nor am I a chemistry expert; just an engineer who's seen both the good and bad side of things.

If you are not familiar with Robert Bryce, I would suggest his substack blog.

May I presume to offer a reading suggestion: "The Whole Story of Climate," by E. Kirsten Peters. She is a geologist from Eastern Washington, and her book is as much a history of climate (she delves into the eras and epochs, as well as the pioneering work by Agassiz and others), and offers some very well-supported recommendations for dealing with climate change.

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The scientific community encourages this because of the money associated with research, positions in government, employability at universities. This has been covered before and the case for economic gain in the science community is overwhelming.

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You are exactly correct, sir, and I completely agree, but my question was, why do we tolerate it? If the anti's can question my funding, or my heritage for that matter, there is no reason we couldn't question the voracity of their results, regardless of their pedigree or their research home. I read recently in a Smil paper that "Goebbels would be stunned to see with what universal success his slogan of repeating a lie so often it becomes new truth has taken the global root, precisely because the soil is receptive: utterly brainless mass of mobile-bound individuals devoid of any historical perspective and of any kindergarten common-sense understanding." I can look for the reference if you need it.

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Hi All

I know that CO2 and climate is a fun topic for discussion and I don’t mind people discussing it.

Though I would ask that you have those discussions on the post dedicated to that topic and focus here on this post.

https://rogerpielkejr.substack.com/p/how-carbon-dioxide-emissions-change

Thanks!

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There is clear data to show that the Earth has warmed on average since the 1800s. The Earth demonstrates that most clearly through decay of glaciers but temperature data also support it. That much should not get lost even if hurricanes are not yet more frequent than they used to be. It is definitely hotter than it used to be. Climate change is real.

According to the climate establishment, this climate change we have already experienced and observe is due to increased greenhouse gases, primarily CO2. The climate establishment believes that as CO2 continues to rise in the 21st century, we will gradually see other climatic effects than a simple rise in average temperature, including more wild fires, hurricanes, floods, droughts, etc. Rising sea level is a biggee but very complicated. The climate establishment also tends to believe that we are already beginning to observe more wild fires, hurricanes, floods, droughts, etc. than in the past and as Roger has pointed out, has scared a gullible public into believing this without basis.

There is nowhere that I can find in all the literature that clearly and finally demonstrates that CO2 is indeed the cause of the known and proven temperature rise since the 1800s. There are popular phrases such as "CO2 forms an infrared thermal blanket" but this is incorrect for many reasons, mainly because energy transfer in the lower atmosphere is not primarily by IR and the CO2 bands are saturated anyway.. There is a pretty good explanation not known by most, but even that is qualitative and has not been quantified with detailed analysis. It goes like this: Increased IR transmission due to higher CO2 at higher altitudes raises the major region of the atmosphere where the earth radiates energy to space, and since that region is cooler, the earth is slightly less able to get rid of energy. I think that is basically correct. Even though rising CO2 is not the sole cause of climate change, it is a predominant cause. The point is that there is a very good theoretical reason (aside from data) to think that CO2 causes temperature increase.

Based on that, I think the climate establishment is right that as CO2 continues to increase in the 21st century, it will get hotter. It seems logical that fires will get worse. What about hurricanes, floods, droughts, etc.? I haven't seen any convincing evidence that these will get worse as CO2 increases but it doesn't tax my imagination to think that they might possibly get worse as oceans warm and ice melts.

Are we already experiencing these effects other than temperature rise? It seems that the climate establishment got the timing wrong and CO2 has to increase further before these effects might occur.

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Jul 22·edited Jul 22

Or to paraphrase Nate Silver/Progressives/Leftists: "SOMEBODY needs to do SOMETHING!" Never mind that doing nothing is in many cases better than doing something largely misguided because it is still misunderstood. Never mind that climate (hot and cold) periods in pre-industrial history happened BEFORE anthropogenic pollution and burning of fossil fuels; do we know those causes?

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Jul 22·edited Jul 22

I have finally decided to support Roger, because as a 'science historian' without the dubious confirmation of an academic title, but much published work, I have grown very suspicious of those that claim 'certainties' about the future based on analysis using mathematics they don't understand the limitations of. This dates back to the 18th century and the replacement of Newton's dynamic universe with one based on algebraic statics. Part of that, is the development of the idea of stochastic systems, systems that because of definite closure of the number of variables, were capable of analysis with strict algebraic rules. This came out of the desire to understand games of 'chance', to be able to predict reliable odds at the gaming table. A pack of cards has 52 members, it cannot be analysed if subject to unknown rules, it sometimes has 48 or, 56 cards. The idea that linear statistics is a valid approximation to the physical world and can be used to predict a future, has dominated Western society for the last 300 years. However, real systems are non-linear, they cannot be tied into such a neat closure. Systems based on the concatenation of a fixed set of variables have singularly failed to accurately predict the future - Claudius Ptolemy failed, as was obvious after 1500 years. To those who complain that Claudius Ptolemy was a simulacrum, not based on physics, must come to terms with the fact that what replaced it, the Sun centred system of Copernicus, was merely a rearrangement of the variables using similar mathematics. It took Kepler and Newton to try and find a physical explanation for the data of observation, but even this required the generation of an occult physical cause, 'universal gravitation' which, although it could justify the mathematics, was incapable of a physical explanation. Einstein, by means of a non-linear model, space-time, was able to equate a system explanation but failed to show how it could be stable and was forced to introduce, a 'cosmological constant' which he later admitted, was his greatest mistake. I know of only one successful mathematical prediction of the future in the history of science. That of John Harrison's prediction that a pendulum clock made on his principles, running at a large amplitude in air, 'would keep time to an accumulated error of 1 second in 100 days'. That claim has been substantiated by work carried out by the clockmaker Martin Burgess and myself. Harrison was using a non-linear conception of the action of the relationship between the variables perturbing the clock as early as 1730, by 1763 he was firm in his conception and was able to state not only the magnitude of the error, but that its very existence was essential to the observation of stability. In effect, a stable system where all the errors coincidentally summed to zero round a steady state, was a physical impossibility. He was of course, ignored and it was not until the 1970s was work started to investigate seriously his claims. Yet the assumption of such a 'steady state' lies at the heart of climate modelling - a single variable, the level of CO2 in the atmosphere and a fixed energy input from the Sun is deemed to explain all! Harrison, as a follower of Newton, analysed what was there, not what he thought was there. There is little sign of the 'closed' mathematics of Euler and Laplace in the 'Principia Mathematica's pages. The very idea of a defined equilibrium as a guaranteed solution to a problem was an anathema to Newton. One major discovery made in the 1980s by David Harrison, whose PhD thesis at Leeds university in 1988, clearly showed that the response of non-linear systems to perturbation could not be treated as the simple additive model used in linear algebra. Non-linear systems produced noise distribution under perturbation that displayed a tendency to increase with time, as part of a move to a new temporary 'steady state' - behaviour was markedly different in transient. Due to 'jumps' in the distribution of energy within the system. peaks and troughs in behaviour no longer were simply additive - this was known to John Harrison. Thus, the simplistic assumptions of stochastic systems and their mathematics had little chance of predicting accurate futures - they could predict a range of futures, but without the ability to fully quantify the non-linear relationship between all the variables and a defined outcome. The ability to recognise this difference in behaviour between linear and non-linear systems has been known for a long time - back to work carried out by Van der Pol in the 1920s. However, the classification of such behaviour as 'chaotic' is a mistake - it is really the result of real dynamics! Stochastic models are really an attempt to reduce a dynamic model to one of 'statics'.

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It’s embarrassing for me, as a scientist, to see academics studying instead of what do do about climate change- studying how to get people roused up via propaganda studies, as say Yale Climate Connections.. I think the first of the Climate 12 step program would be to “admit that changing the world’s energy sources will be difficult” and be open and transparent about choices and whether they are physically, economically and socially realistic. The second would be “consider that one country can ratchet down but no country can do the work by themselves, they need to consider what will make less-carbon intensive energy sources attractive to other countries”

Third is “target, based on history, appear to be meaningless”. I haven’t thought of the rest yet…

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“In fact, the IPCC currently concludes that we will not this century be able to detect with high confidence changes in the statistics of most weather events beyond internal variability”

And so everything and everybody is lying 24/7, like on so many other subjects. This is the Democratic Party Roger supports, inveterate liars, and 95% of the media.

And somehow, it’s Putin’s fault that we don’t trust media, politicians and institutions anymore.

Alex said it best.

“We know they lie.
They know we know they lie.
We know they know we know they lie.
And yet they lie.”

Aleksandr Solzhenitsyn

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Hi Roger - your article makes it seem like the IPCC is unambiguous in its position that there is no signal for extreme weather events. However, this is also what the IPCC states:

"It is an established fact that human-induced greenhouse gas emissions have led to an increased frequency and/or intensity of some weather and climate extremes since pre-industrial time, in particular for temperature extremes. Evidence of observed changes in extremes and their attribution to human influence (including greenhouse gas and aerosol emissions and land-use changes) has strengthened since AR5, in particular for extreme precipitation, droughts, tropical cyclones and compound extremes (including dry/hot events and fire weather). Some recent hot extreme events would have been extremely unlikely to occur without human influence on the climate system. {11.2, 11.3, 11.4, 11.6, 11.7, 11.8}"

https://www.ipcc.ch/report/ar6/wg1/chapter/chapter-11/

On the website, the first sentence in the above paragraph is actually bolded.

That is some strong language in the IPCC, so it's entirely possible for folks to come to this conclusion not by dismissing the IPCC findings but by actually reading it too. So that's a position that can be taken even by folks who ARE trying to read the best-available source of climate science... and it wouldn't be fair to lump them into an uninformed group.

Note: I know you're aware of that passage, and have an article outlining why you think that was incorrectly inserted. But I just want to make the point that one can't hold the IPCC up as the gold standard for passages that we're aligned with, while pointing fingers at it for passages that we disagree with, right?

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Hi Neville

I don’t see much of anything at odds in that passage with what I’ve written in this post.

That said, there are indeed some contradictions between WG1 and WG2 and the Synthesis report

In such situations I defer to the WG1

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The parts of your post I see at odds

QUOTE

- In fact, the IPCC currently concludes that we will not this century be able to detect with high confidence changes in the statistics of most weather events beyond internal variability

- Formal detection of change in the statistics of extreme weather beyond observed variability is highly unlikely for most metrics anytime soon, apart from those associated with temperature changes — according to the IPCC;

- Ubiquitous claims that hurricanes, floods, and drought (and various other extremes) have become more intense or frequent (regardless of cause) in the context of documented variability are simply wrong

UNQUOTE

These seem (to me) at odds with what the IPCC also seems to say, which I pasted above -- indicating "strengthened" evidence for both detection and attribution for temperature extremes, precipitation, droughts, cyclones and compound events.

That may well have been an incorrect insert. If the IPCC has internal contradictions and political meddling, that is a huge problem -- for without it we're left without a reliable source for interested minds who want to go beyond the popular media.

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Are the media claims "simply wrong?" or just not "formally detected?"

The Higgs bosom existed [to the extent that anything "exists" in quantum physics] before it was formally detected with 6 sigma confidence

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