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The Alsup Aftermath

The presentations from the Climate Science tutorial last month have all been posted (links below), and Myles Allen (the first presenter for the plaintiffs) gives his impression of the events.


Guest Commentary by Myles Allen

A few weeks ago, I had an unusual — and challenging — assignment: providing a one-hour “tutorial” on the basic science of human-induced climate change to a Federal District Court in San Francisco. Judge William Alsup had requested this tutorial to bring him up to speed on the fundamental science before proceedings begin in earnest in a case brought by the cities of San Francisco and Oakland, on behalf of the people of California, against a group of major fossil fuel companies, addressing the costs of climate change caused, they argue, by products those companies have sold.

The format was straightforward — two hours each for the plaintiffs and the defendants, and the judge had provided us with a series of questions on the essential physics that he wanted addressed, as well as requesting a timeline of how our understanding of climate change has evolved over the past 150 years. My presentation was followed by Professors Gary Griggs, showing detailed projections of sea-level rise and its impacts on California, and Don Wuebbles, presenting key findings from the latest US National Climate Science Special Report (also speaking for the plaintiffs). Between Gary and Don, the Court heard from Theodore Boutrous, a lawyer speaking on behalf of Chevron, one of the defendants.

The case was fairly widely covered, (here’s an example) and most of the attention was, understandably, on what the oil companies had to say: the fact that Gary, Don and I agreed with the IPCC was hardly ever likely to be newsworthy. But I’ve had a few requests since about what I presented — including from some students who spotted that a carefully compressed summary of climate change science might be quite handy revision material. So, with exam season nearly upon us, here it is — or at least, here is what I would have presented if I’d got through it all: in preparing this material, I had completely failed to anticipate the number and depth of Judge Alsup’s questions, so we only got as far as the Charney Report.

Prior to the hearing, Andrew Dessler on Twitter, Gavin Schmidt at RealClimate and Oliver Milman at the Guardian all had a crack at the judge’s questions:

I was definitely more ambitious and I go into more detail than Gavin, Andrew and Oliver on how attribution works, partly because that’s what I do, but also because just telling the judge “the IPCC says the warming is pretty much all human-induced and 80% of that is CO2” would have been a bit circular, having been involved myself in those IPCC assessments since the 1990s.

My contribution had its ups and downs — a low point was definitely when Judge Alsup declared “your chart sucks” in response to a powerpoint slide (right) which showed an artist’s impression of the Nimbus 4 satellite at the expense of a graph of how the spectrum of outgoing long wave radiation changed in response to rising greenhouse gases between 1970 and 1997. Frustratingly, the chart he wanted (from John Harries’ 2001 paper) was hidden under the pretty picture, but we were already late and I chickened out of breaking open the powerpoint to move figures around in a live courtroom. But the high point came just a few seconds later, when he asked “so, how much did the temperatures [of carbon dioxide molecules emitting energy to space in those critical wavelengths of the infrared] fall over those 27 years?” — showing that, after only half-an-hour, and despite my obscure charts, he had already got a better grasp of the basic mechanism of the enhanced greenhouse effect than many.

I’ve restored that spectrum to its rightful place in the version below, as well as adding some more material on molecular dipoles at the beginning, since Judge Alsup (and others since) had questions about how it was that carbon dioxide molecules could act on infrared radiation over a much larger volume than the molecules themselves actually occupy. I’ve also added some more material later on to address other questions that came up. The material I actually covered at the time is all available on the court record.

The edited presentation runs for just under 45 minutes, and I’ve broken it up into five segments. I’ve also put up the powerpoint in case you want to use some of the graphics in your own teaching. I hope it’s useful.


Tutorial: The basic science of human-induced climate change

Part 1
Part 2
Part 3
Part 4
Part 5

Presentation: The basic science of human-induced climate change

Text adapted from original post at ECI with permission.

132 Responses to “The Alsup Aftermath”

  1. 1
    Marc Cotnoir says:

    Wow! What a great set of resources for those of us who are always being asked about climate science and who are always looking for opportunities to educate people who are interested!!

  2. 2

    Excellent effort. My own efforts will be giving talks on climate change (and its reasons)over the past 500 million years to local folks in this very rural region of upstate New York (before showing them the changes occurring recently and the reasons behind them). But I haven’t heard yet what the global mean temperature was for 2017. Has that been determined? And, if so, what was it?
    C. W. Dingman

  3. 3
    mike says:

    Alsup has produced a meaningful contribution to the law and climate change with the request for production of the science. It’s good to have this in the legal record.

    April 15 – 21, 2018 411.07 ppm
    April 15 – 21, 2017 409.53 ppm

    I think we are in the trough of a LN following a pretty large EN event. Next EN event is going to make a lot of headlines.

    see you there!

    Mike

  4. 4
    Tony Loman says:

    Faithful reader of Real Climate for many years now. This is one of the most useful posts ever published on this site in my opinion. Clearly presented, great graphics. Spend 45 minutes and get educated about an immense problem. The St. Louis University Climate Summit ended yesterday. Great presentations but these would have been a nice set of videos to present there. Will send the link to anyone I think might have the patience to spend a little time learning the science and its historical development.

  5. 5
    William says:

    Question – Alsup asked for the other oil companies to file their own responses so that there would not be post hoc differences with Boutrous’ presentations that emerged.
    Perchance any links to those filings and any comments on their content and possible intent??

  6. 6
    Susan Anderson says:

    @Mike or someone: I have you can define LN and EN. I’m more of a layperson than most of your audience, but have been following weather/climate events. In the US northeast, we are particularly gobsmacked by recent weather – our series of northeasters and the cold, along with some rather obvious sea level rise in Boston. I’m deeply curious about the broader significance of the current short-term (say, since winter just past) in the context of the broader picture. I’ve seen the blue blobs of temperature anomalies and read – as far as I am able to comprehend – the materials on the breakdown of the AMOC, along with following cryosphere melting.

    also @mike: the link on your name is broken.

    back on topic, thanks for the update and links to information. If I may presume, nice work!

  7. 7
    Hank Roberts says:

    for CW Dingman, LMGTFY:
    https://www.google.com/search?q=global+mean+temperature+for+2017

    Click the “tools” button then click “all results” (the default) and instead choose “verbatim” so you find pages containing all the words in your search string, not just any one of them.

  8. 8
    John Mashey says:

    For those unfamiliar with Judge Alsup, he is well-known in SF Bay Area & is not exactly your average judge.

    See THE JUDGE’S CODE

    “The judge spent almost an hour explaining this particular program to me, going over each of the various inputs that can change shortwave radio propagation, as well as the science behind it. The interview turned into an impromptu physics tutorial as he patiently explained the solar flux, K-index, and the ionosphere to me.”

  9. 9
    Hank Roberts says:

    … [Judge Alsup] asked “so, how much did the temperatures [of carbon dioxide molecules emitting energy to space in those critical wavelengths of the infrared] fall over those 27 years?” — showing that, after only half-an-hour, and despite my obscure charts, he had already got a better grasp of the basic mechanism of the enhanced greenhouse effect than many.

    Thank you Judge Alsup.

    And thank you Dr. Allen and the RC Group for giving us more information about what happened there.

  10. 10
    Hank Roberts says:

    Repeating the pointer from the previous thead to the site that collects the court documents:

    Hat tip to WC (Stoat) for the pointer to the court document files:

    http://climatecasechart.com/case/people-state-california-v-bp-plc-oakland/

  11. 11
    Eli Rabett says:

    Without tooting Eli’s horn too much, and although it was only an answer to one of the questions, here is all you need to know about question 2, the role that O2, N2, etc play with links to a three parter

    http://rabett.blogspot.com/2018/03/dear-judge-alsup-tldr.html

    Since the Judge is a ham radio operator, IEHO the thing to have played on that is included in part two of this is that the mechanism is very similar to a dipole antenna (or in the case of N2 and O2 to a quadrupole)

  12. 12
  13. 13
    James Wilson says:

    The students protesting gun violence were able to crystallize their vulnerability to gun culture in a way that adults (including President Obama) have been unable to do.
    Can we somehow ask for their help and leadership on climate? Remember many of us older people will be long dead before the difference between the business as usual pathway and whatever path the world takes makes itself evident. Climate is our failure but their problem. Once again they are in the bullseye of people who do not care enough for their grandchildren to examine their ideological commitments to lying. No meeting of scientists nor avalanche of TED talks will have the impact of young people speaking their truths about climate.
    Any ideas???
    Chuck

  14. 14
    Myles Allen says:

    Thanks, Eli. I like your movies of the CO2 molecules bending and stretching — if only I’d spotted these earlier they would have been in the powerpoint for sure (and might have saved me having to do a chicken-dance, which may have rather undermined my credibility). Can I put them into an update? Is there a source, or are they just yours?

    Myles

  15. 15
    Mack says:

    This Myles Allen, right at the very start, right at the heading of the “basic science” lecture…says….”Both temperature and density of absorbing CO2 molecules decrease with height”… and shows a nice little coloured diagram with red molecules closer to the ground and fewer, blue, colder molecules further up in the atmosphere.
    What’s wrong with this bloke, Myles Allen? He’s purported to be an atmospheric physicist, but doesn’t he know the temperature profile of this Earth’s atmosphere? Hasn’t he heard of the thermosphere? The molecules may thin out further up, but they certainly don’t get colder. In fact, with an active sun, these molecules can get upwards of 1500deg C…they can actually be seen to glow with heat (along with waste nitric oxides), by newer outer satellites…SABER study.
    So this “basic” science is not so basic after all. What is basic, as observed in the SABER study, is that the upper atmosphere acts as a thermostatic shield….keeping us, cooler, from that hot blazing ball in the sky.
    This Myles Allen chappie, with his “basic greenhouse” science, obviously doesn’t want to consider anything further than the tropopause….either that, or he’s just intent on treating the Judge and the rest of us, like unthinking fools.

  16. 16

    Mack, #15–

    This Myles Allen chappie, with his “basic greenhouse” science, obviously doesn’t want to consider anything further than the tropopause….either that, or he’s just intent on treating the Judge and the rest of us, like unthinking fools.

    Or–just a random thought here–maybe he’s not discussing parts of the atmosphere completely irrelevant to the question in hand?

    A radical suggestion, I know, but Prof. Allen is a smart guy and you never know what these smart ones get up to. I’ve even heard whispers that there’s this thing called ‘scoping’ that academics do sometimes when they just have, say, 45 minutes to speak. Maybe it’s in the Climategate emails somewhere?

  17. 17
    Jon Kirwan says:

    I also enjoyed the talks and the slides. (The slides alone almost speak for themselves. So that was very good.)

    I particularly enjoyed the slides that, when combined (1) provided an overview of hotter and cooler CO2 molecules as it relates to how they are seen from outer space and from profile — because this will make it easier for me to explain this process to others; (2) walked through the volcanic and solar activity vs assigning importance to CO2 changes — because this another way to help make it clearer, too, but in another way; (3) discussed CO2 induced warming and ocean rise vs different choices we might make — because this helps point out why every day’s delay matters; and (4) showed Figure 1 from William Nordhaus’ “Strategies for Control of Carbon Dioxide” and then super-imposed upon that the global mean temperature in colors showing pre-paper and post-paper periods — because this helps to show just how far back it was possible to make reasoned projections without the aid of a more nuanced and modern understanding.

    Thanks for taking the added time to put this together for “the rest of us.” Appreciated.

  18. 18

    Great compilation Miles – congratulations!

    Two small comments on the carbon cycle history:

    The ocean buffering chemistry was already worked out by Arrhenius (actually by a colleague of Arrhenius, Högbom). The key insight provided by Roger Revelle was that it takes time to mix anthropogenic CO2 into the ocean’s interior. He and Hans Suess tried to quantify this by analysis of measurements of radiocarbon in the ocean (Revelle and Suess, 1957).

    The “need for zero CO2 emissions”, at least for stabilising atmospheric CO2, was well known already in the 1970s (e.g. Siegenthaler and Oeschger, 1978).

  19. 19
    Hank Roberts says:

    > Mack wrote:

    … thermosphere … The molecules may thin out further up, but they certainly don’t get colder….

    > Myles Allen wrote, op. cit.:

    … [Judge Alsup] asked “so, how much did the temperatures [of carbon dioxide molecules emitting energy to space in those critical wavelengths of the infrared] fall over those 27 years?” — showing that, after only half-an-hour, and despite my obscure charts, he had already got a better grasp of the basic mechanism of the enhanced greenhouse effect than many.

    I’ll believe Judge Alsup, not Mack, got it right on this point.

  20. 20
    Hank Roberts says:

    PS for “Mack” — I looked for a basis for your “SABER study” comment.
    Odd what Google finds. Is this the source for your information?

    Global warming debunked: NASA report verifies carbon dioxide …
    https://www.naturalnews.com/040448_solar_radiation_global_warming_debunked.html

    and

    Global warming debunked | Apocalypse – End of world?
    endoftherworld.blogspot.com/2013/06/global-warming-debunked.html

    May 22, 2013 – “Carbon dioxide and nitric oxide are natural thermostats,” says James Russell from Hampton University, who was one of the lead investigators for the groundbreaking SABER study. “When the upper atmosphere (or ‘thermosphere’) heats up, these molecules try as hard as they can to shed that heat back …

    Good little molecules, I hope they keep trying as hard as they can.

  21. 21
    Nick O. says:

    Professor Allen, this is terrific, thank you. Thank you also for putting in the effort to make the case in court. Thanks also of course go to Profs Griggs and Wuebbles. I have had the pleasure of meeting Don a couple of times – a few years ago now – and we had some interesting discussions about the hydrosphere and land-hydrosphere interactions.

    Regarding #15 above and Mack’s comments, well yes, the thermosphere does indeed get hot, but its temp. fluctuates across a wide range, changing diurnally and with the activity of the Sun and so on. It also amounts to only a very small proportion of the mass of the atmosphere. I am not fully up on the figures but it’s something like 0.002%, which is pretty small. So there is likely to be only a very small interchange between the thermosphere and the layers below it. An analogy I have seen on a NOAA (or it might have been NASA) website is that it’s a bit like a small candle in a very large room: the candle is certainly hot, but the size of the flame is so small any heating effect in the room is overwhelmed by the other factors affecting the system. ‘Small’ here refers to the mass of the flame relative to the air in the rest of the room. Not a perfect analogy, I know, but I think it makes the main point well enough.

  22. 22
    Eli Rabett says:

    Myles, if Eli may be informal, the gifs came from https://scilearn.sydney.edu.au/OrganicSpectroscopy/?type=Infrared at the University of Sydney

    by way of
    https://uvachemistry.com/tag/asymmetric-stretch-of-co2/

    They were created by Adam Bridgeman.

  23. 23
    Eli Rabett says:

    Mack,

    Eli thinks you may just have had your Marshall McLuhan moment, but it was quite creative.

    Your argument if quite the flowers that bloom in the spring have nothing to do with the case, just as the temperature in the thermosphere and ionosphere have nothing to do with the greenhouse effect but the decline of temperature with altitude in the troposphere is determining.

    Best
    Eli

  24. 24
    Mac says:

    Mack, #15-
    You’ve obviously completely missed the point. Try watching the videos again to learn something, instead of to fabricate critiques with no basis in science or reality.
    -The original Mac

  25. 25
    Dan DaSilva says:

    Is judge Alsup a climate scientist? If not how can he make a technical judgment on the subject? A non-scientist cannot possibly form an independent valid opinion by technical judgment on this sacred subject. (Sorry for the “sarcasm” but this is the opinion and operating mode of the left so it is really not sarcasm )

  26. 26
    Eli Rabett says:

    Dan,

    Like it or not that is what judges do all the time as part of their jobs. You are railing against the system.

  27. 27
    Hank Roberts says:

    DDS:

    this is the opinion and operating mode of the left so it is really not sarcasm

    The people you are arguing with are not here.

  28. 28
    jgnfld says:

    @25

    As in the recent Minnesota case, Judge Alsup’s opinion need not be “independent” nor “technical”, it merely has to judge the likelihood on the balance of probabilities which side of the parties before him made the better, more backed up case.

    That is a pretty straightforward decision, actually. Politics really doesn’t override reality always, as you appear to think.

  29. 29
    Jon Kirwan says:

    #25
    Is judge Alsup a climate scientist? If not how can he make a technical judgment on the subject?

    Judges are required to make judgments. It’s what they do. Preferably, we hope, after being informed by the available facts and knowledge (scientific or otherwise) at the time.

    A technical subject within a case doesn’t prevent a judge from being competent to make decisions about that case. DNA evidence is, for example, quite technical and relies upon countless theories and experimental results that are only thoroughly understood well by just a few among us. As with DNA evidence which is only a part of a case, I’m sure the judge will take the scientific evidence as just that — evidence that is part of a case.

    This particular judge has also followed a path that does him credit. He sought a dialogue to find out a degree of agreement. Finding that degree of agreement avoids wasting time where it isn’t needed; helps to unearth presumptive agreements that don’t actually exist; and may also focus everyone’s time where it is needed. This suggests the judge is genuinely interested in addressing the remaining questions.

  30. 30
    Ray Ladbury says:

    Dan DaSilva,
    Pray. Where did anyone say anything that would suggest that a layman cannot form a valid opinion on a technical matter? You really should work on your reading comprehension…maybe have someone help you with the bigger words.

    A layman can look at what the true authorities say on the subject. They can look at the consensus of authorities on the subject. They can even learn a whole helluvalot about the subject so that they can see which authorities are most insightful. Argument from authority is only a logical fallacy if the authorities cited lack relevant expertise.

    They will not, however, budge the needle one iota on the subject until they publish peer-reviewed research on the subject that the experts find useful. If their opinion contradicts the scientific consensus, and they do not have relevant expertise themselves, then they are cranks.

  31. 31

    Note how Dan conflates “the left” with scientists.

  32. 32
    Dan DaSilva says:

    I missed something let me rephrase “a layman cannot form a valid opinion on a technical climate matter” (add following) “unless it is in agreement with the scientific consensus.”

    In the history of the science, the consensus has always been totally accurate . If by chance you are not really sure of what facts are, use the word “denier” (because it is an easy code word to get approval from your tribe).

    Call that person a denier even if they deny nothing and agree with consensus but they think there is uncertainty about some claims (because you must defend your tribe from all outside forces).

    Now don’t get me wrong all tribes (even my tribe and me personally!) behave like this, it’s just that in the case of “climate change” the “left tribe” is doing it. Could I be wrong in my opinions about “climate change”? Yes of course but the above points are still valid (only in my opinion of course).

    For more information on the root of this very human behavior refer to the work of Jonathan Haidt.
    https://www.youtube.com/watch?v=uogEbb0WOJE

  33. 33

    DDS 32: In the history of the science, the consensus has always been totally accurate

    BPL: Why do you hate Ray Bolger?

  34. 34
    Radge Havers says:

    DDS @ ~ 32

    Metaliteracy has been discussed here enough that you should understand how you can use knowledge of how science works and reason to help sort out the issues that you pretend to worry about. Instead you lecture from generalities, hypotheticals, and what seem to be deliberate, irony-challenged mischaracterizations.

    BTW, I’m not seeing where soft social scientist Haidt attempts to refute the hard science on climate change. He does however seem to point the finger at pretty much everybody when it comes to blocked progress on addressing climate change.

    Perhaps you should spend some alone time contemplating the phenomenon of false balance in pop discourse as well as the difference between rhetoric and reason.

  35. 35

    In the history of the science, the consensus has always been totally accurate…

    Er, no, since the consensus obviously changes with new information/analysis, and the essential underlying reality–or so we assume, at least–does not. I know you know that. Now you know that I know it, too.

    And yes, that includes climate science specifically: for example, IPCC Assessment Reports reflect changing information and perspectives throughout the entire sequence of five reports, as in estimates of SLR, hurricane frequency and intensity, loss of Arctic sea ice cover, drought, and of course climate sensitivity, to name but a few.

    Signing off in the light of a flaming strawman, I remain,

    Your humble and obedient servant, etc., etc…

  36. 36
    Dan DaSilva says:

    28 jgnfld

    “Politics really doesn’t override reality always, as you appear to think.”
    What I think is that it does many times. How many depends on how much politics is invested in the decision.

    In my opinion “climate science” is highly invested in politics. But I have no problem with a judge deciding it.

    I was just wondering what the opinion would be of turning all important decisions which involved some technical judgment over to a panel of the SCIENTISTS with a PEER REVIEW? I think this is a very bad and awfully terrible idea but the readers of RealClimate may have other opinions.

  37. 37
    Hank Roberts says:

    DDS: If by chance you are not really sure of what facts are, use the word “denier”

    I think you mean “use the word ‘leftist'” there.

  38. 38
    Jon Kirwan says:

    #32
    let me rephrase “a layman cannot form a valid opinion on a technical climate matter” (add following) “unless it is in agreement with the scientific consensus.”

    There is a long discourse on this topic in the Michigan Law Review, March 1994, “Objectivity in Legal Judgment.” It is available for free, so don’t complain about costs. And it’s only one person’s view, but it is still worth reading, if only to see the mental machinations on the question.

    I believe the following selection is fair-use here:

    Another lesson learned from the scientific and moral-rationalist conceptions of objectivity is that objective judgments, on whatever conception, are constrained judgments. Constraints upon judgment can take different forms. On the scientific-ontological conception, the natural world as it is – independent of scientists’ beliefs, goals, desires, or representations of the facts – constrains which judgments count as objective. Only those that correspond to the world as it is qualify. On the scientific-methodological and the dialogical moralrationalist conceptions, procedures supply constraint. Only judgments that survive certain processes can count as objective. The method may be individualist (as in the individualist scientific-methodological conception), collective (as in the socialist scientific-methodological conception), dialogical (as in the dialogical moral-rationalist conception), or hypothetical (as in the monological moral-rationalist conception). Constraint guards against arbitrariness, whimsy, and idiosyncrasy; it ensures that not just any old judgment qualifies as objective. — Heidi Li Feldman, Michigan Law Review, March 1994, “Objectivity in Legal Judgment,” page 1227

    All of us, and that includes you and me and pretty much everyone else in the world, cannot ever live long enough, nor have enough memory for, nor have the wisdom and insight required to personally know all things and every level of detail. Even the use of so much as a voltmeter to measure a voltage requires thousands (perhaps millions) of assumptions. Yet we use the voltmeter to good effect without having personally performed every experiment to the best of our abilities, comprehensively testing every idea ever proposed to explain them, and arriving at our own personal certainty that the number we are reading is within the stated accuracy and precision for the voltmeter we are using.

    We simply use the voltmeter, trusting that companies with profit, legal, and a host of other unknown motives; together with all of the many scientists and engineers who have supplied their lifetimes to this area; have provided a tool that we can reasonably apply as an end-user with some rational expectations.

    Of course a layman relies upon the work of others that have gone before. But what you fail to realize, or at least recognize here, is that we can prod and poke into that body of work. For example, I’m no expert on voltmeters, but I have personally performed my own experiments regarding the ideas of magnetic flux and its rates of change on conductors; Faraday’s law. And I’ve personally performed experiments creating batteries from chemicals. I’ve personally constructed large-scale “crystals” and irradiated them with a Klystron in order to demonstrate to myself the idea of diffraction. And I can, if I choose to do so, pick almost any idea that is within my means to perform and then go out and test what I’m being told.

    I can assure you that so far as my own experiences have shown me, and some of my instrumentation has been part of everything from measuring re-entry temperatures on the Space Shuttle to research studying the effects of small temperature changes on types of brain cells, that I’ve rarely found anything that made me question the theories I was taught. In general, poking here and there, I’ve found that the modern state of science knowledge is rather robust and soundly reasoned, if not always intuitive.

    Finally, as I wrote earlier, technical evidence is just that — evidence. Other considerations flow into forming a legal opinion.

    You seem to propose that an entire case only boils down to some scientific technicality where you claim the judge (whom you call a layman) cannot

    There is much more to a case than just one bit of technical evidence. So you are wrong to suggest the judge must be an expert on this, or any other highly specialized, technical subject. No one claims the judge will base their decision entirely on the point of a single line of evidence.

    I think you are trying overly hard to make a mountain out of what is really a mole hill here. There seems to have been substantial agreement between the parties about this “technical climate matter” you seem so focused on. So I’ve no idea why you are pressing so hard. Even if they disagreed about it, judges can and do make judgments on cases where technical evidence is presented. But that’s not even the case here. The parties agree, broadly speaking, on those points. So even if there were an argument to be made, you picked the wrong horse.

    I suspect the judge will focus efforts on the disagreements, not the areas of agreement. The parties both accept the well-supported science results and conclusions. You need to move on, too. And in moving on, why don’t you go read through the article I mentioned at the outset? It gives you one person’s thoughts for you to mull over. Might broaden your perspective a little.

  39. 39
    Ray Ladbury says:

    BPL: “Note how Dan conflates “the left” with scientists.”

    Probably due to reality’s well known liberal bias.

    DDS: OK, who do you think is more likely to be right
    -thousands of experts, familiar with the data, methods and models of a field, with combined experience into millennia, actively working each day to understand and advance the field and who all agree based on the evidence-
    -or-
    Some random jerkwad on the Intertubes who doesn’t even know the difference between a statistical and a physical model?

  40. 40
    AndyG says:

    @32, no, a layman could form a valid opinion that the subject was unsettled, if the evidence to date appeared to support more than one interpretation. That’s not the case with the overwhelming consensus of evidence that informs climate change. It is the case in (plucking an example) dark matter’s MACHOS vs WIMPS debate.

  41. 41
    Dan DaSilva says:

    31 Barton Paul Levenson
    The two (“the left”, “scientists”) were in the same paragraph if that is what you mean by “conflates”. If you still think that, there is no remedy.

    Once went to a debate between Teller and Pauling on nuclear power and Edward Teller was not a lefty. I have read no study on the percentage of scientists who are on the left. If you have a link to one I will read it.

    Thanks

  42. 42
    Dan DaSilva says:

    30 Ray Ladbury

    “Argument from authority is only a logical fallacy if the authorities cited lack relevant expertise.”

    Yes, climate scientists definitely have the relevant expertise. Is expertise enough for trust? Well, it can be used, but it does not appeal to me.

    “budge the needle” The needle is not the truth. How many times in history has the needle been wrong? Oh but wait we have PEER REVIEW and this MODERN science, it can not be wrong. This is THE argument from authority which I reject. Each person is allowed there own needle, at least in our current form of government.

    If we lived in the dictatorship the needle could rule. Would that be better?

    While we are on the subject of Arguments. My favorite is the “Argument from Reason” by CS Lewis

    Thanks

  43. 43
    Mac says:

    Re #32, DDS:

    “a layman cannot form a valid opinion on a technical climate matter” (add following) “unless it is in agreement with the scientific consensus.”

    That is a falsehood.

    How about: A layman can form a valid opinion on a technical climate matter, if they can support it with sound logic and evidence, irrespective of the scientific consensus. The trouble for you is, the scientific consensus is the consensus precisely because the logic and evidence have been widely evaluated and generally considered sound, until a new discovery can upend it.

    And there’s no shortage of cases of this. In the 1980’s, Dr. Barry Marshall intentionally ingested an H. pylori broth, and overturned the medical consensus that the bacterium was unrelated to peptic ulcer disease. Dr. Marshall was no layman, but any layman who did his same degree of work and analysis, and applied the same degree of rigor, could have accomplished the same feat of science.

    The problem today is, most “deniers” do not care to do the work that is necessary to overturn the consensus. Or when they do, they find themselves joining the consensus, instead! (Dr. Richard Muller comes to mind, possibly?)

    I actually have no problem with someone saying, “I accept that the experts have reached their conclusions based on sound evidence and reasoning as we best understand it today, but it’s not enough to convince me because I think further research will overturn it.” But deniers today don’t say that. Instead, they say, “The underlying theory is wrong. The data is unreliable. The logic is unsound. The researchers are unethical. Therefore the conclusions are invalid.” — And that is the tribal approach.

    So there is nothing stopping your proverbial layperson from forming a valid, contrary opinion. Except, of course, the fact that they should first do some science to support their point.

    That’s how science is supposed to work. So rally your “Dr. Marshalls” to the denier cause, and show the climate community your revolutionary evidence!

  44. 44
    nigelj says:

    Dan DaSilva @32

    “I missed something let me rephrase “a layman cannot form a valid opinion on a technical climate matter” (add following) “unless it is in agreement with the scientific consensus.”

    This isn’t always correct, and only you are claiming this strawman argument Dan. Nobody is censoring criticism of some theory or consensus. But valid means “having a lot of sound logic, basis in fact, cogent argument, and consistency with accepted, long established scientific laws”. Not once have you done this, and instead you resort to insinuation, irrational claims, selective use of facts, generalisations, and political comments and the bottom line is you aren’t persuading anyone here. Your claims don’t stand up to scrutiny by the experts.

    Victor is similar but without the overt politics, and just ignores what people say, doesn’t understand complexity, and raises red herrings. And lets be honest, history shows complete laypeople seldom have genuinely new scientific insight.

    “In the history of the science, the consensus has always been totally accurate . If by chance you are not really sure of what facts are, use the word “denier” (because it is an easy code word to get approval from your tribe).”

    Sarcasm again. Consensus has sometimes been wrong, (eg risks of saturated fats are not as high as once thought), however the agw consensus is based on far more research over a longer time period than on saturated fats, and consensus theories have a much better record than crank theories.

    “Call that person a denier even if they deny nothing and agree with consensus but they think there is uncertainty about some claims (because you must defend your tribe from all outside forces).”

    Your problem is you don’t agree with the consensus. The agw consensus is that human activity is the main or dominant cause of climate change since the 1970’s and you don’t subscribe to this to my knowledge, and disagree about almost anything else as well. That’s what you have been posting. Rarely have you stated what you actually agree with.

    Prove me wrong and state unequivocally that you think humans are at least the main cause of recent climate change, – or even just a large part of the cause. Bet you won’t.

    “Now don’t get me wrong all tribes (even my tribe and me personally!) behave like this, it’s just that in the case of “climate change” the “left tribe” is doing it. Could I be wrong in my opinions about “climate change”? Yes of course but the above points are still valid (only in my opinion of course).”

    This tribal theory applies to peoples political affiliations such as liberal or conservative, or membership of other social groups, and we know liberals do tend to accept climate science more than conservatives from polls by Pew Research etc, although its not black and white. However there’s a difference between peoples politics and their jobs. The scientific community comprises a mixture of political beliefs, and as I have explained the scientific method and peer review process works and competition among scientists does well to stop beliefs of any kind intruding on science, but you just don’t learn. In other words there’s a demonstrable difference between peoples voting preferences and beliefs, and social groups, and how they do their various jobs.

    Its also important to realise the extremes of political belief we see in the media are not representative of ordinary people, as the media becomes dominated by people with extreme agendas and attention seekers. Most people are rather nearer the “centre” politically, and that often the tribal behaviour is more related to occupational classes, personal interests, and where people live rather than politics. However this is based on my reading in a general sense, and clearly America is more divided politically than most countries.

  45. 45
    Dan DaSila says:

    Is MIT Professor Richard Lindzen a denier? This is an honest question because I find him very convincing. If you want to call a denier then I am in great company, thanks for the compliment. Call him a stupid hack and I will know who the stupid hack is. He has videos all over youtube and his arguments are measured and thought out.

    One thing I am sure of is that India and China may voice support for carbon use reductions but they want US and Europe reductions and will not reduce their own until it fills their economic interest.

    So let the “war” continue and let the truth come out. How will this whole argument end? I think it will end in a slow whimper and not a bang. The truth will be in the middle somewhere where both sides will declare victory. I personally think that middle is Lindzen and not Mann but we will see. For climate science will never be decided in “peer review” it will be decided when the earth gives us the answer and that will take many years after many if not all of us have passed.

  46. 46
    Dan DaSila says:

    42 nigelj, quote
    “Prove me wrong and state unequivocally that you think humans are at least the main cause of recent climate change, – or even just a large part of the cause. Bet you won’t.”

    I think/guess the range is between 25 and 50 percent. So why do you think I would disagree will this? I am not saying this to prove you wrong.

    Just because I challenge almost everything presented here at RealClimate does not mean I know for sure what that valve is. For all, I really know it could be 150 percent and we would have cooled without CO2. I just object when someone says they KNOW that the value is 100 percent.

    So what is the problem? The problem is that I am “right wing” and that is the only real problem, I am not in your tribe not on your team. But that’s OK I can live with lefties and even like them. Just as I have enjoyed these discussions.

    PS: If any of you are right-wing true believers I apologize for the generalization.

  47. 47

    Thanks to all of you who work every day to provide us on the political front lines of this fight with the strength and ammo we need!

  48. 48
    izen says:

    @-nigelj
    “Consensus has sometimes been wrong, (eg risks of saturated fats are not as high as once thought), …”

    In that case the consensus was at least partly skewed by the efforts of private enterprise with an economic interest in providing a refined energy source. There was an attempt to minimise and divert any blame for harm caused by its own product.

    By both funding scientific research, and influencing the reporting in public media the industry cast doubt on suggestions the product it was supplying might be a more significant factor in morbidity.
    Sugar.

  49. 49
    Ray Ladbury says:

    DDS, The problem is that you don’t understand scientific consensus. It is not a bunch of scientists coming together and figuring out what they believe. It is a question of what they have to believe (in terms of facts, models techniques…) to be productive in their field.

    A climate scientist might not like that there are positive feedbacks that raise the climate sensitivity above 2.0. He or she might fervently wish it were otherwise. However, a model that yields a sensitivity less than 2 is very unlikely to yield insight into the climate because it simply doesn’t look like Earth. So, they construct a model that looks like Earth, and a moderately high sensitivity is a consequence.

    The way a scientific consensus gets overturned is with evidence–be the overturner a layman or a scientist. And the more successful a theory has been (in terms of verified predictions), the more difficult it is to overturn. The consensus model of climate has a long track record of successful predictions–that makes it very unlikely that it is fundamentally wrong.

  50. 50

    Ray Ladbury says:
    27 Apr 2018 at 12:46 PM
    BPL: “Note how Dan conflates “the left” with scientists.”

    Probably due to reality’s well known liberal bias.

    It’s the Jacobin bias that I worry about.

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