On being alarmed

The Climate Change National Forum has a new Fact Checker section. I think the idea is to post news articles about climate change and allow the scientists involved in the Climate Change National Forum to comment. It sounds like a good idea, but I know that some (myself included) have some reservations. One issue is that there are some articles that should probably just be ignored, so giving them exposure on a credible climate science site may well do more harm than good. Another problem I can see is that the typically vocal pseudo-skeptics will probably insist that the scientists criticise any article that is remotely alarmist (in their view at least) while finding reasons to excuse mistakes in articles they support. Although I don’t have much respect for the vocal, online, pseudo-skeptics, I can’t fault their enthusiasm and commitment.

One of the first articles they’ve included is one by David Roberts called If you aren’t alarmed about climate, you aren’t paying attention. David Roberts is, I think, having a years break from writing and I can see why he would want such a sabbatical. I hope he’s having a relaxing time. Andreas Schmittner comments to say

Here is the first problem: “We know that 2 degrees C is where most scientists predict catastrophic and irreversible impacts.”

This is an assertion and it is wrong. Climate scientists don’t predict catastrophic impacts. They project impacts.

Of course, I suspect he’s completely correct that scientists simply predict impacts. Whether or not these are catastrophic is a judgement and not some kind of scientific fact. However, journalistically, it seems fine to ascribe an adjective to these impacts. Partly, that’s the point of journalism. Journalists are meant to interpret what’s being said. Maybe he could have made it clearer that it’s his judgement that the impacts are likely to be catastrophic (although, I suspect he wouldn’t be alone in this judgement). Also, does Andreas Schmitter mean that he’s wrong that they will be catastrophic, or does he simply mean that he’s wrong to suggest that scientists have specifically predicted catastrophic impacts. I suspect the latter, but it’s not completely clear.

Andreas Schmittner then goes on to comment further and acknowledges that there is scientifically valid information in this article and finishes this comment with

There is reason for concern, but not for panic. I think we can still resolve the issue and avoid the worst impacts.

This is actually the reason I wanted to write this post. There seems to be quite a lot of this type of rhetoric going around at the moment : “don’t worry, everything will be fine”. Matt Ridley and Bjorn Lomborg are another pair who are presenting this type of message (in addition to incorrectly claiming that adapting will be cheaper than mitigating).

Here’s my issue with this rhetoric. What do such people think others are alarmed about? Do they think that people are alarmed because they’re worried that the climate will magically change in a way that’s catastrophic. No, the alarm is about the possibility that we will continue to change our climate in a way that produces catastrophic impacts. How is “don’t worry, everything will be fine” in any way a suitable argument against being alarmed. If anything, it makes it worse. I’m not concerned about climate change per se, I’m concerned that we will continue to increase our emissions and follow a pathway that leads to catastrophic impacts. People saying “don’t worry, everything will be fine” while we continue to increase our emissions, just makes me think they’re burying their heads in the sand and hoping for the best. I’d also have much more confidence in these views if they were typically accompanied by suggestions as to what we should do, rather than suggestions that we shouldn’t really do anything now.

So, essentially, I’m concerned that our policy makers will listen to those (like Lomborg and Ridley) who’s basic argument is (paraphrasing) “don’t do anything now, and don’t worry because our future selves will find a way to solve any problems they face in the future”. Yes, I’m sure our future selves will find ways to solve the problems they face, but it’s going to be a damn site harder if we don’t bother starting to think about it today. We are an incredibly resourceful and innovative species and we’ve solved many complex problems in the past. However, typically we’ve solved them by actually doing something, rather than simply hoping that someone will come along in the future with some kind of brainwave. If I’m alarmed it’s not specifically about climate change, it’s about the possibility that there are people out there who think that “don’t worry, everything will be fine” is a sensible policy option. It might make a fun song, though.

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124 Responses to On being alarmed

  1. As usual, something I’ve said has ended up more controversial than I had intended. It seems this

    Whether or not these are catastrophic is a judgement and not some kind of scientific fact. However, journalistically, it seems fine to ascribe an adjective to these impacts. Partly, that’s the point of journalism.

    has provoked some discussion. My thinking was as follows. The sentence We know that 2 degrees C is where most scientists predict impacts, doesn’t really say anything. Therefore, if a journalist is going to write a section about the future impacts of some level of warming, they’re going to want to describe that in some way. My point was not that the journalist is suddenly correct to use the term “catastrophic”, my point was that criticising them because scientists didn’t specifically use the term catastrophic (because they probably can’t) doesn’t really make sense. Part of the job of a journalist is to report on the significance of some scientific result. If you’re going to criticise the journalist, criticise them because their judgement is poor (it won’t be catastrophic) not because they haven’t precisely used the phraseology that scientists would use.

  2. Rachel M says:

    Your reasoning is similar to Peter Hadfield’s in his latest video:

    I’m not alarmed by a problem that our intelligence will allow us to mitigate; I’m alarmed at our ignorance and gullibility that leads us to wilfully ignore it.

    And I agree!

  3. Perhaps it’s useful to make a distinction between alarming and alarmist – interesting article on this by James Risbey – from 2008 – but still rings true http://www.sciencedirect.com/science/article/pii/S0959378007000465 He writes at the end: “The ‘alarming’ discourse takes a firm view in regard to both problem and solution. While climatologists may be divided about the degree of urgency that should be reflected in the climate discourse, the stakes are high. Shooting the messengers is not going to solve the problem. We need to develop as good a sense of the threat as we can get in the limited time available and choose a discourse that sets the appropriate course.”

  4. Rachel M says:

    On the use of the word catastrophic, I think scientists tend to use very conservative and often quite technical language, so I don’t think it unreasonable for a journalist to use different words.

    I think the word catastrophe is appropriate in some circumstances. If we lose the Great Barrier Reef because of ocean acidification then catastrophic is appropriate.

  5. Rachel M says:

    That’s a great article, Brigitte and worth quoting more of:

    This article reviews evidence to support claims that climate change can be viewed as ‘catastrophic’, ‘rapid’, ‘urgent’, ‘irreversible’, ‘chaotic’, and ‘worse than previously thought’. Each of these terms are imprecise and may convey a range of meaning. The method used here is to assess whether the conventional understandings of these terms are broadly consistent or inconsistent with the science, or else ambiguous. On balance, these terms are judged to be consistent with the science.

  6. Brigitte,
    Thanks, that is a good point.

    Shooting the messengers is not going to solve the problem. We need to develop as good a sense of the threat as we can get in the limited time available and choose a discourse that sets the appropriate course.

    I do think that there is an awful lot of this going on (maybe I do a bit myself 🙂 ). It’s probably one concern I have about CCNF’s Fact checker, because it could end up simply criticising articles that are generally good.

  7. johnrussell40 says:

    Andreas Schmittner uses double standards when he says

    “Climate scientists don’t predict catastrophic impacts. They project impacts”

    and then goes on to say,

    “I think we can still resolve the issue and avoid the worst impacts.”

    So as a climate scientist he doesn’t make predictions… except for the prediction that we’ll be able to deal with it. You’re right to be critical, ATTP.

  8. I’ve been having a rather confusing Twitter debate with Chris Shaw (not helped by him implying that I somehow support state-controlled media) about my comment regarding journalism. I think I’ve now worked out the issue. I think Chris’s issue was that he’s read my post as endorsing the statement

    We know that 2 degrees C is where most scientists predict catastrophic and irreversible impacts.

    which wasn’t really what I was trying to get at. My very simply point was that if you’re going to criticise an article, simply saying “scientists don’t predict what impacts will be catastrophic” doesn’t really seem good enough, especially as science will never really do this (given that catastrophic isn’t really a well-defined scientific term). I think, and Chris is welcome to correct me if I’m wrong, Chris’s issue is that the 2 degree limit is really arbitrary and in fact ignores that many will face severe impacts well before we reach the 2degree limit – hence it is a rather elitist limit given that the wealthy countries will be both able to cope better and will be less affected than the developing world.

    To be clear, I agree and I wasn’t intending to suggest that I endorse the statement made by David Roberts. My very simple point was that if you’re going to critique articles, then do a better job than simply saying “scientists don’t specifically predict catastrophic impacts”. To a certain extent, this may actually illustrate why the CCNF Fact checker will do more harm than good. How does it help to pick on some factual issues if you can’t address the broader, and often more important, points as to how we should evaluate the significance of the impacts of climate change.

  9. Surely in order to be an effective communicator you have to use adjectives that convey the seriousness of the situation. of course science can’t make any value judgement, but the communicator can.

    Here’s some very eminent and respected scientists and economists using alarming adjectives to communicate the science…

    “We are in a planetary emergency”- Prof. James Hansen, former Director of the NASA Goddard Institute for Space Studies

    “Virtually all of us are now convinced that global warming poses a clear and present danger to civilization.” – Prof. Lonnie Thompson, director of the Byrd Polar Research Centre

    “Climate change is accelerating more rapidly and dangerously than most of us in the scientific community had expected or that the IPCC 2007 Report presented” – Prof. Sir. John Houghton, former co-chair of the IPCC

    “Avoiding dangerous anthropogenic interference in the climate – is in fact unattainable, because today we are already experiencing dangerous anthropogenic interference. The real question now is whether we can still avoid catastrophic anthropogenic interference in climate.” – Prof. John Holdren, US Presidential Science Advisor, Former President of the AAAS

    “There is a widespread view that a 4°C future is incompatible with any reasonable characterisation of an organised, equitable and civilised global community. A 4°C future is also beyond what many people think we can reasonably adapt to. Besides the global society, such a future will also be devastating for many if not the majority of ecosystems. Beyond this, and perhaps even more alarmingly, there is a possibility that a 4°C world would not be stable, and that it might lead to a range of ‘natural’ feedbacks, pushing the temperatures still higher” – Prof. Kevin Anderson, former director of the Tyndall Centre for Climate Change Research.

    “We have reasons to believe that if the world doesn’t do anything about mitigating the emissions of greenhouses gases and the extent of climate change continues to increase, then the very social stability of human systems could be at stake” – Prof. Rajendra Pachauri, head of the IPCC.

    “Thinking through the implications of 4 degrees of warming shows that the impacts are so significant that the only real adaptation strategy is to avoid that at all cost because of the pain and suffering that is going to cost.” – Prof. Neil Adger, University of Exeter.

    “The current burden of greenhouse gas in the atmosphere is in fact more than sufficient to cause catastrophic climate change,” – Prof. Tim Flannery former Chief Commissioner of the Climate Commission

    “The two degree guardrail is somewhere around or above the tipping point. So two degrees is not a good compromise! It is the dividing line between dangerous and catastrophic climate change’.” – Prof. Hans Schellenhuber Director of the Potsdam Institute for Climate Impact Research.

    “There is a growing sense of panic in those who really understand what a 4°C world might be like”- Prof. Will Steffan, Director of the Australian National University Climate Change Insitute.

    “With current policies in place, global temperatures are set to increase 6 degrees Celsius, which has catastrophic implications,” – International Energy Agency Chief Economist Dr.Fatih Birol

    “The failure of our generation will haunt humanity until the end of time”- Prof. Ross Garnaut, Author of the Australian Government’s Climate Change review.

    “Do the politicians understand just how difficult it could be? Just how devastating four, five, six degrees centigrade would be? I think not yet. Looking back, the Stern review underestimated the risks and underestimated the damage from inaction.” – Lord. Prof. Nicholas Stern

    “In the face of an absolutely unprecedented emergency, society has no choice but to take
    dramatic action to avert a collapse of civilization. Either we will change our ways and build an
    entirely new kind of global society, or they will be changed for us. ”
    – Gro Harlem Brundtland, Paul Ehrlich, Jose Goldemberg, James Hansen, Amory Lovins, Gene
    Likens, James Lovelock, Suki Manabe, Bob May, Hal Mooney, Karl-Henrik Robert, Emil Salim,
    Gordon Sato, Susan Solomon, Nicholas Stern, MS Swaminathan, Bob Watson

    Click to access Blue-Planet-Laureates-Environmental-and-Development-Challenges-The-Imperative-to-Act.pdf

    You get the idea. And I could just have well quoted army generals or world leaders etc.

    Surely, if such a broad range of leading experts on climate science, who are in the best position to judge the weight of evidence, deem it appropriate to say that we must take ’emergency’ action if we are to avoid potentially ‘catastrophic’ consequences then we should listen to what they have to say!

  10. ‘For every complex problem there is a simple answer. And it is always wrong’.

    Thanks for the clarification – the point is about it being fine for journalists to apply their own adjectives to the science, which is what you write. It is not fine because they are all repeating the two degree dangerous limit theme. If that is fine, I will stop worrying about melting Arctic ice, shifting jet streams and increase in extreme weather events. They are obviously not the result of climate change because the Earth has warmed by only 0.8 degrees and there will be no impacts to be concerned about until 2 degrees.

    I believe climate change to be a crisis. I would like to ground our responses in some form of shared value system. The 2 degree is the dangerous limit meme prevents that process from being manifest. It is a top down discourse which underplays climate risk, does not lead to effective mitigation policy, and will be abandoned for a four degree limit as soon as the 2 degree limit becomes inconvenient.

  11. verytallguy says:

    In the recent debate on the IPCC AR5 reports, the degree of alarm seems to have been influenced by the timescale.

    There seems to be a line of argument, which I’ve seen more or less explicitly from Tol, Curry, Lomborg which goes like this:

    (1) Climate sensitivity might be as low as 1.5degC/doubling. If it is…
    (2) Catastrophic impacts by 2050 are inconceivable
    (3) Catastrophic impacts by 2100 are unlikely

    Therefore… we should do nothing

    The truth is much more alarming. WG3 SPM:

    Baseline scenarios, those without additional mitigation, result in global mean surface temperature increases in 2100 from 3.7 to 4.8°C compared to pre‐industrial levels10 (median values; the range is 2.5°C to 7.8°C when including climate uncertainty, see Table SPM.1)11 (high confidence).

    WG2 Box SPM1 judges the risk as between moderate and very high with even a 2-3 degree warming against all five of

    Unique and threatened systems:
    Extreme weather events
    Distribution of impacts:
    Global aggregate impacts:
    Large-scale singular events:

    In other words, the *best* case scenario without mitigation is a high risk in almost all impacts by 2100. That’s the *best* case (2.5 degrees)!. The worst case (7.8 degrees) is literally off the scale (See WG2 Box SPM1 Fig 1), and the median (3.7-4.8) is devastating; the threshold for near complete loss of the Greenland ice sheet is judged by WG1 to be less than four degrees.

    Plus, I’m not really sure why, but the IPCC in general focus on impacts to 2100. If, of course, we get to 2100 with a four degree rise already and still more will be in the pipeline then the worst impacts would be yet to come.

    Should we be alarmed?

  12. verytallguy says:

    ATTP said

    However, typically we’ve solved them by actually doing something, rather than simply hoping that someone will come along in the future with some kind of brainwave

    This strikes a real chord with me, and I might have a little rant.

    We know, and understand the laws of f****ing physics. They provide absolute constraints we cannot escape from. Future solutions to climate change which violate the laws of thermodynamics are not going to happen.

    Humanity didn’t put a man on the moon by assuming that future humans would invent antigravity machines. We understood the constraints and cleverly and urgently designed machines which operated within those constraints.

    Likewise, we know, right now what the possible solutions to climate change are; we need to urgently implement them.

    Rant over.

  13. Joshua says:

    Anders –

    Climate scientists don’t predict catastrophic impacts. They project impacts..”

    Could it be that those two sentences are intended to draw the distinction between “predict” and “project,” not to question whether the impacts scientists project will be “catastrophic?”

  14. I also just had an article about the “Fact Checker”. My main peeve is that the nonsense articles are posted on CCNF initially undisputed without comment. Then the scientists have to scramble and quickly put some response up. A great way to make scientific commentary as bad as journalistic comments. Furthermore, the comments of the scientists are below the fold and thus automatically less credible as the main article and many people do not read comments in the first place.

    That problem now seems to be solved. CCNF has promised to put the science response above the fold.

    That also alarmist articles are put up for critique is actually the main think I like about the “Fact Checker”. The lower limit of climate change is much better restrained as the upper limit. And the pseudo-skeptics do not make much of an effort to present a credible case. Thus it is much easier to clearly show that an article of a pseudo-skeptic is wrong as an article of an alarmist. Forcing scientists to get out of their comfort zone and also critique those is not bad. That critique will automatically be more nuanced in most cases, because it is hard to rule out something at the upper limit.

  15. Chris,
    Thanks for the comment. Much easier than Twitter 🙂

    Firstly, I agree with you. When I said “fine”, I was really just meaning that journalists will use adjectives that one would – typically – not find in scientific papers. So, the really simple point I was making was that criticising something because it uses an adjective that one wouldn’t find in a scientific paper seems simplistic. As you say, that doesn’t mean that every time they use one that they’re right to do so. However, if one is going to criticise what’s been said, then one should do more than simply suggest that they’ve used an adjective that wouldn’t be found in paper.

    FWIW, I completely agree with what you say and my intent wasn’t to suggest that the 2 degree limit is the right limit. To a certain extent what I was getting at at the end of the post was not far off what you suggest at the end of your comment. The idea that we can just expect future generations to somehow be clever enough to solve this problem without us starting to do something now seems absurd and is just a form of burying our heads in the sand.

  16. Johsua,

    Could it be that those two sentences are intended to draw the distinction between “predict” and “project,” not to question whether the impacts scientists project will be “catastrophic?”

    It’s certainly possible that Andreas Schmittner was trying to distinguish between predict and project which is a valid point. I do think, although could be wrong, that he was also highlighting that scientists can’t define an impact as catastrophic, but happy to be proven wrong if that wasn’t the case.

  17. Victor,
    To be fair, the CCNF Fact Checker may work very well. I’ll be very pleased if it does. My concern would be that it ends up promoting articles that are largely nonsensical and quite hard to rebut; the only sensible response being this. Also, there could be a tendency to nit-pick at what are essentially quite good articles.

  18. Yes, one the good comments was that many articles do not contain facts that could be checked, but some want to act as if they are science and are thus forced to make checkable facts.

  19. VeryTallGuy: “Humanity didn’t put a man on the moon by assuming that future humans would invent antigravity machines.”

    Genius! I completely stole it (with acknowledgement of course)… hope that’s OK.

  20. Dan,
    Need a tweet button on your posts 🙂

  21. verytallguy says:


    not only stolen, but improved. Truly you are standing on the shoulders of leprechauns.

  22. ATTP: I need to get off Drupal, it’s not very good for that kind of thing!

    “Truly you are standing on the shoulders of leprechauns.”

    On their heads, actually. I’ve got one tied to each foot.

  23. AnOilMan says:

    VIctor said: “My main peeve is that the nonsense articles are posted on CCNF initially undisputed without comment. Then the scientists have to scramble and quickly put some response up.”

    Its called Nerd sniping;

  24. nnoxks says:

    I am extremely confused as to how the phrase “worst impacts” is any less a value judgment than the phrase “catastrophic impacts.” “Better” and “worse” are the very definition of unscientific value judgments. Yet many of the Very Serious Scientists who reject uses of the word “catastrophe” as entirely unscientific seem happy to use terms like “worst” or “beneficial.” Language – how does it work?

  25. Steve Bloom says:

    Here’s a non-paywalled copy of the article Brigitte quoted. Although it appeared six years ago, it’s well worth a read.

    Brigitte having raised her head above the parapet once again, I’ll note that the article thoroughly trashes the views of Mike Hulme, beloved of the Making Science Public crowd, and ask how, having taken the article on board, one can reasonably not only continue to promote Hulme but e.g. choose to feature the likes of Ben Pile (who is 100% about opposing what he sees as “alarmism”).

    I would suggest that the present academic debate about climate change has a lot in common with the debate that Korean ferry captain had with himself before deciding to have his passengers stay below-decks. I’m sure his defense will be to note what a big surprise it was that the ferry capsized so quickly. After all, he’d never seen it do such a thing before.

  26. AnOilMan says:

    nnoxks: No. Better and Worse are very technical and very scientific. Sometimes it can be hard to identify the metric, but afterwards it works just fine.

    This kind of better/worse analysis is absolutely done in oil and gas.

    I’m currently evaluating various algorithms for mud pulse telemetry with the result, Better or Worse than existing telemetry. My metric is ability to absolutely decode correct values, and standard deviation with respect to the confidence of the decode.

    Everything you own and do is dependent on this kind of analysis performed by people like me.

    Have a great day.

  27. Steve Bloom says:

    CCNF may be able to fix the way they handle the fact-checking section, but it appears that they lack a defense mechanism against aggressive cranks like Judy Curry.

  28. nnoxks says:

    AnOilMan: I detect a note of anger that is a little confusing as well. You are using jargon that I do not entirely understand, due to my lack of scientific training. But it sounds, from what you are saying, that you are seeking to answer the question whether a particular algorithm is “better” or “worse” in the sense of “more accurate” or “more efficient.” Clearly “better” and “worse” have technical and scientific meaning in that context. But using the phrase “worst impacts” of climate change is not at all the same thing. Andreas Schmittner says: “The valuation is up to the reader. Is melting of the Greenland ice sheet catastrophic? Is a longer growing season desirable? Those are difficult questions that climate science has little to contribute to.” Then he says: “There is reason for concern, but not for panic. I think we can still resolve the issue and avoid the worst impacts.” Do you think he is using “worst” there in your highly technical sense, or is it the very kind of value judgment he was decrying? I suggest the latter, but I am happy to hear why you think otherwise.

  29. Steve Bloom says:

    Let me try a paraphrase: “The valuation is up to the reader. Is human extinction catastrophic? Is a diverse and thriving global ecology desirable? Those are difficult questions that climate science has little to contribute to.”

  30. As much as I agree with AOM that “worst” can be defined, I think I see what nnoxks is suggesting. If scientists can’t have a value judgement with respect to the impacts, then why do we have to “avoid the worst impacts”? By saying this, I can see that Schmittner is making some kind of value judgement about these impacts, which then seems to slightly contradict his suggestion that scientists only “project impacts”, not whether they’re catastrophic or not.

    There was a related issue that I was considering. If scientists who study the impacts of CC have to remain objective, then presumably they should have no view as to whether or not an impact is likely to be catastrophic or not. This would seem to mean that they should have no view as to whether or not it’s appropriate for a journalist to use a term like catastrophic, as they should have no view either way. If they object to it’s use then that implies that they think the impact will not be catastrophic which would then seem to contradict the idea that they should remain objective with respect to an impact being catastrophic or not.

  31. nnoxks says:

    ATTP, thank you, that is exactly what I was suggesting. I certainly agree with AOM that “better” and “worse” are not unscientific value judgments when it comes to determining whether a particular method is “better” or “worse” for achieving a particular goal.

  32. Eli Rabett says:

    Schmittner and Bouldin are engaged in tutt trolling

    “Half the people in the world will die” is a perfectly value neutral statement.

  33. Eli,
    Indeed, it does seem that way. I feel that I should maybe apologise to you for not allowing Brad to carry out his “Dana libels Lindzen” theme here. It seems to have moved onto your site, although it did produce an impressive comment thread, and Willard appears to have had some fun. 😉

  34. Steve Bloom says:

    I’m pretty sure David Roberts was referring to the Copenhagen Diagnosis when he wrote “We know that 2 degrees C is where most scientists predict catastrophic and irreversible impacts.” The concluding paragraphs of the executive summary:

    Delay in action risks irreversible damage: Several vulnerable elements in the climate system (e.g. continental ice-sheets, Amazon rainforest, West African monsoon and others) could be pushed towards abrupt or irreversible change if warming continues in a business-as-usual way throughout this century. The risk of transgressing critical thresholds (“tipping points”) increases strongly with ongoing climate change. Thus waiting for higher levels of scientific certainty could mean that some tipping points will be crossed before they are recognized.

    The turning point must come soon: If global warming is to be limited to a maximum of 2 °C above pre-industrial values, global emissions need to peak between 2015 and 2020 and then decline rapidly. To stabilize climate, a decarbonized global society – with near-zero emissions of CO2 and other long-lived greenhouse gases – needs to be reached well within this century. More specifically, the average annual per-capita emissions will have to shrink to well under 1 metric ton CO2 by 2050. This is 80-95% below the per-capita emissions in developed nations in 2000.”

    OK, that’s pretty strong. They don’t resort to the “C” word, although they appeared to endorse its use when discussing (albeit minimizing the prospect of) a possible large-scale methane hydrate release leading to a PETM-like climate excursion. Even so, I don’t think a journalist can be blamed for using it after reading the quoted passage. In terms of its ordinary meaning, Google has “an event causing great and often sudden damage or suffering.” Sounds about right to me.

  35. Steve Bloom says:

    Apparently Eli will tolerate any amount of Brad, unless the latter starts resorting to nonsense doggerel. Although, come to think of it, somebunnies might say that’s already happened.

  36. Tom Curtis says:

    Anders, quoting the full first comment by Schmittner would avoid some confusion. It makes clear that he objects both to the word “prediction” and to the word “catastrophic”. The former because the pojections are conditional on certain human activities (and assumptions about a lack of tipping points) and hence by changing our behaviour, we can change the outcomes. The second because he thinks scientists cannot make the call as scientists on whether something is catastrophic, or even not desirable. For him, scientists qua scientists have an olympian objectivity that cares no more, nor less for the extinction of the human race than they would for the extinction of Plasmodium falciparum.

    Scientists, however, are citizens as well, however. Many are also mothers or fathers, or uncles or aunts (or will be). As such, they are entitled to a less olympian view. As it happens, Denis Bray and Hans von Storch have published a recent survey of the opinions of climate scientists (“A survey of the perceptions of climate scientists 2013”). In it they ask (question 28, page 57), “How convinced are you that climate change poses a very serious and dangerous threat to humanity?” Of the 286 valid responses to the survey, 280 answered this question – indicating perhaps that only 2.1% of climate scientists maintain that the objectivity of a scientist trumps even their view as a citizen of the implications of their work.

    Of those that responded, 18.57% (52) responded with a 4 or less. That indicates that 81.43% (228) are substantially convinced that climate change “… poses a very serious and dangerous threat to humanity”. Of respondents, 41.79% (117) were “very much” convinced of the threat.

    The phrasing of the question is itself of interest. A threat to “humanity” is not just a threat to humans individually, but to the some of humans as a whole. A “dangerous threat to humanity” is strictly speaking, an extinction level, or near extinction level threat. I suspect many respondents did not so parse it, however. It certainly represents a catastrophic threat, however, by any reasonable definition.

    It follows that in the view of most climate scientists (>80%), the impacts they objectively predict as scientists are, overall catastrophic in their view as citizens. Schmittner is, therefore, wrong (or at best, pointlessly pedantic) in his criticism of the article. Being pedantic myself, he is also wrong in his criticism of the word “prediction” rather than “projection” in that Roberts tied the catastrophic impacts to a particular temperature increase (>2 C).

  37. BBD says:

    From Hansen (2007) Scientific reticence and sea level rise:

    I suggest that ‘scientific reticence’, in some cases, hinders communication with the public about dangers of global warming. If I am right, it is important that policy-makers recognize the potential influence of this phenomenon.

    Scientific reticence may be a consequence of the scientific method. Success in science depends on objective skepticism. Caution, if not reticence, has its merits. However, in a case such as ice sheet instability and sea level rise, there is a danger in excessive caution. We may rue reticence, if it serves to lock in future disasters.

    Barber (1961) describes a ‘resistance by scientists to scientific discovery’, with a scholarly discussion of several sources of cultural resistance. There are aspects of the phenomenon that Barber discusses in the ‘scientific reticence’ that I describe, but additional factors come into play in the case of global climate change and sea level rise.

    Another relevant discussion is that of ‘behavioral discounting’ (Hariri et al 2006), also called ‘delay discounting’ (Axtell and McRae 2006). Concern about the danger of ‘crying wolf’ is more immediate than concern about the danger of ‘fiddling while Rome burns’. It is argued in the referenced
    discussions that there is a preference for immediate over delayed rewards, which may contribute to irrational reticence even among rational scientists.

  38. Tom,
    Yes, I agree that he was also trying to illustrate the distinction between prediction and projection.

  39. Tom Curtis says:

    I was going to post the following in the public comments section on the Climate Change National Forum. I find, however, that you need to log into Facebook to comment. I despise facebook, and will not sign up to it just to permit comments at a third site. Anybody who wants to post at the Climate Change National Forum (which I recommend) should feel free to quote me.

    “First, and pedantically, Schmittner is wrong to criticize the use of the word “projections”. A projection is a prediction conditional on certain events. It is most often used of model projections, in which the predictions are conditional on a certain forcing scenario. If the forcing scenario actually transpires but the projections do not pan out, the projections would be falsified. In the article, however, Robert states the impacts are conditional on a particular temperature. Because he includes the conditional, he correctly uses the term “predictions”.

    Second, a journalist reporting on science is not bound by olympian principles of objectivity that care no more about the extinction of Homo sapiens than the extinction of Plasmodium falciparum. Therefore, they are entitled to describe the impacts predicted by scientists as catastrophic. The sentence to which exception was taken can be as easilly interpreted as saying that “Scientists predict impacts I consider catastrophic” rather than “Scientists predict impacts they take to be catastrophic”. Consequently, Schmittner’s and Bouldin’s criticism of the word catastrophic is a tacit attempt to impose on journalists the standards of objectivity. If principled, there criticism of the article should have argued that Roberts should have been less ambiguous about who considered the impacts catastrophic.

    Third, scientists are also citizens, and people. Their obligations as people to be ethical, and as citizens to be good citizens are a higher calling even then their calling to be scientists. And as citizens, and ethical people they have an obligation to consider whether or not the impacts are catastrophic. As such, Roberts may be correct in his statement, even interpreting it to mean that the scientists consider the impacts to be catastrophic. That is, at “… 2 degrees C is where most scientists predict … irreversible impacts” that as citizens they consider to be catastrophic.

    Indeed, that is likely true. A recent survey by Bray and von Storch showed that 81.43% of scientists are more convinced than otherwise that “…climate change poses a very serious and dangerous threat to humanity”, with 41.79% being “very much convinced” (the strongest option available). Even Schmittner lapses into his views as a citizen above when he indicates the the findings are “reasons for concern, not for panic”, and that we can resolve the issue and avoid the “worst impacts”. “Reason for concern” and “worst impacts” both indicate value judgements that have taken him of his olympean peak that he criticizes Roberts for falling from. I assume they are his judgements as citizen rather than a scientist, and that he would fall among the 82% of climate scientists significantly concerned about climate change.

  40. John Mashey says:

    I hate the unadorned word “catastrophic” since it is ill-defined. It would be nice to have agreed-on scales, as for hurricanes.

    Someone may call their house burning down catastrophic, whereas they may not care about a similar fire halfway around the world. Sometimes time-duration seems to matter, where the same damage down slowly does not seem as bad as that which happens quickly.
    For instance, if a really big hurricane hits Miami causes much damage, does that rise to catastrophe? That might or might not happen.
    How about if sea level rise in a flat-area on porous limestone erases Miami and big chunks of S. Florida? Is that catastrophe, or just expensive? Likewise, same question for Bangladesh.

    Is it catastrophe if Oklahoma and big chunks of Southwest get back into dustbowl status for long periods, or just expensive?

  41. Rachel M says:

    … that you need to log into Facebook to comment.

    This makes me cross. On the whole I quite like the idea behind CCNF and I explained why on Victor’s post about it but I really dislike websites that force you to use Facebook. I despise Facebook too and I no longer have an account there so CCNF are effectively locking out people from commenting. And good people like me and Tom 🙂

  42. Tom,
    I think you mean “criticise predictions” in line 2, otherwise a good comment. I’d post via my facebook account, but that might just give me away 🙂

  43. John,
    Sure, I agree that we could be more careful about what we mean by these terms, and maybe simply using “catastrophic” isn’t particularly informative. That doesn’t mean, however, that journalists shouldn’t describe what they think the significance of the possible impacts are.

  44. This blog is a group of old conservative people. 🙂 The reason I wrote a blog post on CCNF was that I could not comment without having a facebook account. 🙂

  45. Rachel M says:

    Make that four good people who can’t comment!

  46. Rachel M says:

    I decided that if my mother is using Facebook (and she is), it probably isn’t the right thing for me. 🙂

  47. BBD says:

    Make that four good people who can’t comment!


  48. BBD says:

    John Mashey

    I hate the unadorned word “catastrophic” since it is ill-defined.

    Often it has a yellowish hue, like straw.

  49. Tom Curtis says:

    John Mashey:

    “I hate the unadorned word “catastrophic” since it is ill-defined.”

    Is this clear enough for you 😉

    catastrophe (n.)
    1530s, “reversal of what is expected” (especially a fatal turning point in a drama), from Latin catastropha, from Greek katastrophe “an overturning; a sudden end,” from katastrephein “to overturn, turn down, trample on; to come to an end,” from kata “down” (see cata-) + strephein “turn” (see strophe). Extension to “sudden disaster” is first recorded 1748.”

    By that definition, the Great Depression was a catastrophe, as also was the Global Financial Crisis of 2008. Global Warming, however, is not a catastrophe on human time scales, although it will bring catastrophes to individual localized areas. It is too slow in terms of the political cycle to be catastrophic, and always will be. On the other hand, on a human timescale, the Permian extinction was not a catastrophe either, but on a geological timescale global warming may shape up as the worst catastrophe yet experienced by life on Earth.

    However, as it stands, global warming with BAU is likely to be worse than the largest global catastrophe experienced by humans to date (whether you count that as the black death, European exploration of the globe with its consequent devastating spread of European diseases of World War 2), but not itself a catastrophe because it is to long in the run up.

  50. Eli Rabett says:

    ATTP, it may seem catastrophic, but Eli follows Muhammad Ali’s strategy with the Brads of the world. Seems to mostly work.

  51. nnoxks says:

    Tom Curtis: I’m not sure what you mean by “not a catastrophe on human time scales.” Do you mean, as you say later, the timescale of “political cycles”? That may be true, since political timescales are (wildly speculating an acceptable average) maybe 5-10 years. But not a catastrophe on human time scales? Surely a 6 foot sea level rise by 2100 would be a global (not localized) catastrophe on a human timescale – certainly some people born today will still be alive then.

    It seems to me that part of the problem is that our massive fossil fuel releases are speeding up a process (climate change) that ordinarily occurs in geological time to the point where the change can, in fact, be observed on human timescales. And that increased rate of change is part of what is so, if I may say, alarming. There are certainly a lot of “unknown unknowns” as our beloved former Defense Secretary/Torturer in Chief might say. And, from that excellent paper you pointed out, it seems like over 80% of climate scientists might agree.

  52. Tom Curtis says:

    nnoxks, the post you are responding to was in part facetious. Never-the-less, in the event of a 6 foot sea level rise by 2100, that represents a rise over three generations. In terms of human life spans, that is a slow rise. Even in historical terms it is not that rapid. My point, however, was that introducing time scales into the equation rather than absolute level of harm puts us into the position of lobsters saying the warming of the pot in which they sit is of no concern because it is a slow warming. By strict definition, it appears, global warming may be no catastrophe while still being the worst crisis life on Earth has ever experienced. Fussing about a strict definition, therefore, seems pointless. Understanding that when people refer to the potentially catastrophic effects of global warming, they do mean a real risk of very serious harm to humans (or humanity) seems more appropriate. I think we agree on that.

  53. Steve Bloom says:

    New and topical:

    Natural climate variability and future climate policy

    Large ensemble climate modelling experiments demonstrate the large role natural variability plays in local climate on a multi-decadal timescale. Variability in local weather and climate influences individual beliefs about climate change. To the extent that support for climate mitigation policies is determined by citizens’ local experiences, natural variability will strongly influence the timescale for implementation of such policies. Under a number of illustrative threshold criteria for both national and international climate action, we show that variability-driven uncertainty about local change, even in the face of a well-constrained estimate of global change, can potentially delay the time to policy implementation by decades. Because several decades of greenhouse gas emissions can have a large impact on long-term climate outcomes, there is substantial risk associated with climate policies driven by consensus among individuals who are strongly influenced by local weather conditions.

  54. John Mashey says:

    Maybe we’re getting somewhere.
    Consider 3D graph, log-log and plot kinds of events:
    X: timescale, from a few seconds (earthquakes) to thousands of years, at least
    Y: geographic locality, ranging from “my house” to Earth
    Z: some measure of effect, like cost, number of people, number of other species affected

    Hence, each kind of event is an (X, Y, Z) tuple and people can draw surfaces that separate catastrophe from non-catastrophe.

  55. Steve Bloom says:

    This too. Can human society reason itself out of something it didn’t reason itself into?

  56. izen says:

    It is only meaningful to describe an event or process as catastrophic if it significantly degrades or destroys something that has value to the person (or group) making that judgement.

    For those who place no value on human civilisation beyond the benefits they directly recieve AGW is too slow a change to degrade the value they measure to be called catstrophic.

    For those who value the continued use of fossil fuels, either because of personal gain or a belief that abandonding the benefits of a cheap energy source is detrimental to human society the move to constrain CO2 emissions might be viewed as a catastrophe.

    There is no external, independent or absolute measure of ‘catastrophic’.

    Facebook = a Granfalloon

  57. Steve Bloom says:

    Eli, in what way does rope-a-doping the likes of Keyes work for you given that so many of your regular commenters, me included, have told you it discourages their participation?

  58. Tom Curtis says:

    I wrote an email to the Climate Change National Forum objecting to the inability to post except by registering with face book. This was the response:

    “Mr. Curtis,

    I too find it objectionable. But until CCNF gets funding, there’s not much I can do about it. When we created the site, I didn’t know of any other plug-in. I have the replacement identified, but that takes a programmer, which takes money.

    We are raising funds here: https://ioby.org/project/climate-change-national-forum (fundraising page is in need of an update).

    Very Respectfully,

    Michael Quirke”

  59. Rachel M says:

    I wonder why they need a programmer if the plugin is already made? Most plugins are free. Or so I thought. It’s looks like they’re using WordPress too which is open source.

  60. The reason for being able to move the “Fact Checker” was also because they would need a programmer and thus funding.

  61. AnOilMan says:

    I think scientists can say whatever they like in public. If its not in a journal, its not a concern. That means you can and should see their human side in public.

    I think that all measurement interpretation and understanding is relative to something else. If you had to hold your breath all the way to the moon, could you? If you had a warp drive, could you?

    I think ‘catastrophic’ as a means of understanding could be confusing. I’d interpret that to mean ‘damaged to the point of no return’.

    In real life I think that could be subjective, but there is the collapse of the Atlantic fisheries;

    Great quotes on that wiki… “What this alludes to is the unfortunate paradox that often accompanies open-access resources and is known by most as the Tragedy of the Commons: what is in the individual’s best interest is not always in the best interest of a society at whole.”

    Climate Change is said to cause this kind of damage, and it may well be irreparable. We have no real experience with how the new earth’s ecological systems will be altered. Experience so far has been ‘worse’ than before. ‘Catastrophic’ is what eventually follows ‘worse’.

    Are there examples of what might be in store?
    “But the reason why has puzzled bird experts for years. It’s a particularly important question because the species which are not migrating earlier are declining in numbers.”

    If the species with declining numbers are important to the food chain, you’ll see catastrophic damage.

  62. John Mashey says:

    Although as far as I know this isn’t a global climate change effect, how about bees?
    If bees disappear, maybe GDP will rise, given all the great new jobs using pollen-laden paintbrushes for fruit trees, as started in China already.
    Of course, birds do their share as well for various plants.

  63. dana1981 says:

    Unfortunately the CCNF fact checker is very naîve. It requires people to read the article with the myths before debunking them – that’s a backfire effect no-no. They really need to read the Debunking Handbook. They also brought Judith Curry on board, who’s already reinforcing myths and misinformation too.

    Apparently they don’t have the technical capabilities or knowledge or budget to fix these problems, but until they do they’re doing more harm than good.

    As for the article in question, Roberts could have phrased the ‘catastrophic impacts’ bit more carefully, but it’s all pretty nitpicky.

  64. The Fact Checker is now structured a lot better.

  65. Steve Bloom says:

    Anything would have been better, but a 5 year old video seems like an odd choice given that there’s been much subsequent research re the Pliocene.

    I am not amused that Andreas identifies himself as a paleo guy but doesn’t seem to know where the WG1 assessment of Pliocene sea level went wrong.

    And in the public comments, n-g’s house troll weighs in with what appears to be a complete fabrication. No fact-checking there!

  66. Steve,
    I’m not a paleo guy, and I don’t know what you mean by WG1 going wrong.

    The most recent paper I have seen is in the latest issue of Nature (Rohling et al). They write:

    We note that the international ‘Pliocene Maximum Sea Level’ (PLIOMAX) project currently estimates ESL at 12–32m for the period 3.3–2.9 Myr ago (M.E. Raymo, personal communication), similar to the Pliocene range of 9–31m used in ref. 4. [Foster, G. L. & Rohling, E. J. The relationship between sea level and climate forcing by CO2 on geological timescales. Proc. Natl Acad. Sci. USA 110, 1209–1214 (2013).]

    IPCC WG1 writes in Chapter 5.6.1 Mid-Pliocene Warm Period

    Estimates of peak sea levels during the MPWP (Table 5.1, Section 5.3.1) based on a variety of geological records are consistent in suggesting higher-than-present sea levels, but they range widely (10 to 30 m; Miller et al., 2012a), and are each subject to large uncertainties. For example, coastal records (shorelines, continental margin sequences) are influenced by GIA, with magnitudes of the order of 5 m to 30 m for sites in the far and near fields of ice sheets, respectively (Raymo et al., 2011), and global mantle dynamic processes (Moucha et al., 2008; Müller et al., 2008) may contribute up to an additional ±10 m. Consequently, both signals can be as large as the sea level estimate itself and current estimates of their amplitudes are uncertain.
    [..Two paragraphs of more detailed discussion of evidence ..]
    In summary, there is high confidence that GMSL was above present, due to deglaciation of GIS, WAIS and areas of EAIS, and that sea level was not higher than 20 m above present during the interglacials of the MPWP.

    Could you explain, what you mean by your comment, and how it’s related to the above excerpts.

  67. BBD says:


    Must admit I’m not clear what you mean either, unless you are thinking about the over-estimates of mid-Pliocene sea level derived from a misinterpretation of the Orangeburg Scarp (Rowley et al. 2013)?

  68. Judith Curry responds to the CCNF affair, a bit late, now that problem is more or less solved. Curry-like (i.e. long) quotes from my post.

    See also my response at Climate Etc. They really did not like the sentence: “Climatology is a mature field and new finding will more likely change the complete picture only little.” 🙂 Still dreaming of Galileo showing that the Earth is not warming.

    The comment:
    Thanks for the plug, even if it is a bit late, because the problem is solved by now. I was complaining about the format of the Fact Checker at CCNF. They were more positive about my input and have now changed the system. The scientists are now responding above the line and are not demoted to responding below the line in the comments. Comments which many people do not read.

    Otherwise I am quite happy with the CCNF. It is a forum with some science that can lead people back to reality, people that would most likely never visit RealClimate and Co. For the same reason Like I like your blog, you cite from the scientific literature and I have some hope that this lets people see the difference in quality of argumentation between WUWT and the literature.

    My comment about 30 to 1 was a response to Mann calling for balance. I was only pointing out that that would be difficult. The fraction of dissenters with blogs is way higher as the fraction of mainstream scientists with blogs. That creates an imbalance that CCNF cannot solve.

    JC: It only takes one such argument, and one person making it That is theoretically true for the scientific literature. I am sure you understand that this is not true for blog-science. Isn’t that why so many dissenters are blogging?

    In praxis it will likely take more than one Galileo or study. Also the refutation of classical mechanics by quantum mechanics and relativity did not change many thinks we already understood at the time. It allowed us to study new things and ask new questions. That was the revolution.

    Climatology is a mature field and new finding will more likely change the complete picture only little. The most uncertainty is in the impacts, improving our understanding there will have to be done one impact at a time. And more likely, one aspect of an impact at a time.

  69. The uncertainty scale may be set from two different perspectives:

    – from the point of view of science forgetting all applied use of the knowledge
    – from the point of view of decision-making

    Both allow for a range of opinions, but I have found many of the views of Judith Curry more in agreement with the perspective of pure science. This is somewhat paradoxical as she has emphasized on many occasions the connection to decision-making, but on the other hand she is a climate scientist and therefore interested in the science itself. From the point of view of pure science the uncertainties of climate science are large. Many essential issues are known really poorly. That includes much of the mechanisms of internal variability. It’s perfectly reasonable to conclude from the point of view of poor science that climate science is far from mature.

    From the second point of view the question is: Do we know enough to act? It’s not, whether the field is a mature science.

    People do disagree on the sufficiency of the present knowledge as basis for acting. Many agree that we know enough for some decisions, but disagree, when the choice involves strong policies. That’s where much of the real disagreement is, but neither those who favor strong policies nor those who accept only some minor action seem particularly willing to argue on the specifics. They seem to feel that they should not give up their principles by agreeing to look for compromises.

  70. BBD says:


    They seem to feel that they should not give up their principles by agreeing to look for compromises.

    What sort of compromises did you have in mind, exactly?

  71. By compromise I don’t mean anything specific, only something that could be found acceptable by more people.

    I didn’t really think as much as the outcome as the process. That would necessarily involve arguing on specifics, presenting arguments, and trying to compare their strengths. It’s important to have long term issues in mind, but the first decisions determine only, what’s done first. Therefore the making them should not be prevented by longer term uncertainties or disagreement on what’s likely or virtually certain in the long term.

    The main point is that discussing the need to act brings nowhere without fully concrete decisions that are implemented without much further delay. Some development will happen anyway, the question is, what to do on top of that. Agreeing on such practical decisions is very likely to involve compromises.

  72. Pekka,

    That includes much of the mechanisms of internal variability.

    Even though this may be true, I’m unconvinced as to its relevance. I was thinking of writing something about this, but since you’ve commented about this I’ll comment briefly here. Internal variability is only really relevant for long-term (multi-decade) climate change if one can find some mechanism by which it can produce some kind of change in radiative forcing. If not, then it simply acts to perturb the system from it’s equilibrium that’s set by the radiative forcings. As I understand it, there is no real evidence for internal variability doing anything other than acting as some kind of short-term variability. So, maybe there is much that we don’t understand about internal variability, but unless there’s a chance that it could be contributing to some of the longer-term warming and hence producing more warming than anthropogenic influences alone, it doesn’t seem as though uncertainty about internal variability is all that important.

  73. Pingback: Critically analysing horse shit | And Then There's Physics

  74. ATTP,

    What do you mean by “relevance”?

    From the point of view of climate science itself AGW is just an application, understanding climatic processes is, what’s essential, internal variability is a major part of that.

  75. Pekka,
    I just meant relevant to long-term climate change. Unless internal variability can produce some kind of radiative forcing, then surely it will only ever be a perturbation about the anthropogenic trend. Maybe I’m thinking too globally here and that even though internal variability is unlikely to produce any change in radiative forcing, it could still influence how our climate will change in response to the changing anthropogenic forcings. It’s, of course, also interesting to understand in itself. I was really just suggesting that not understanding it all that well doesn’t really suggest that – globally at least – climate change won’t proceed broadly as expected.

  76. The point I tried to make in my first comment on this issue is that what’s important or relevant depends strongly on the question. For a scientist interested in the science rather than in climate policy it’s very different from what it is for those who use science only as a source for the needs of policy.

    Many of the controversial arguments of Judith Curry are not controversial at all, when considered purely from the point of view of science.

  77. Pekka,
    I agree that it depends on the question being asked. I’m not sure that I agree that Judith’s arguments are not controversial. The questions she asks aren’t, but from what I’ve seen, the arguments she seems to make (related to variability, for example) show a significant lack of understanding of basic radiative physics, which I would regard as then making them rather controversial.

  78. Can you give an example of such ignorance. I haven’t observed that.

  79. Pekka,
    The Stadium Wave idea seems to suffer from this. How can one have aulti-decade oscillations that produce warming without that being associated with a change in radiative forcing. Admittedly, from what I read of the paper it seemed to present a more balanced picture than one might get if you read just the blog posts. To be clear, I don’t know if Judith understands radiative physics or not. My point was simply that pushing that idea that internal variability could play a big role without discussing the physical mechanism would be, by itself, an illustration of what I’m suggesting. From what I’ve seen, Judith does seem to think internal variability is important, and I don’t see how this is possible unless one can also find some way in which it also produces a change in radiative forcing.

  80. Furthermore I didn’t claim that she would not have presented controversial ideas of scientific content. Whether there’s enough justification for the stadium wave might be an example of that. I write only that many of the arguments that are controversial from the policy perspective are not that as purely scientific statements.

    Furthermore science proceeds often through controversial ideas.

  81. Our commenting overlapped. I have reservations on some parts of the stadium wave idea, but I don’t think that radiative processes are an essential issue in that.

  82. Pekka,
    Ahh, but my point was not that questions are controversial, but that the arguments presented are controversial. Asking what role internal variability plays is a perfectly fine question. Suggesting that it could produce more than half of the warming since 1950 (as I think Judith has) is what I would regard as controversial.

  83. Pekka,
    We’re crossing again.

    I don’t think that radiative processes are an essential issue in that.

    I think it depends what you mean. It’s certainly possible that there could be multi-decade oscillations in our climate may not be surprising. What would be surprising if these could produce long-term warming. Certainly there are some (including Judith I think) who seem to think that the stadium wave can do exactly this. I don’t see how this is possible without producing a change in radiative forcing. So, if one is going to propose that the stadium wave could be contributing to our long-term warming, then one should be willing to discuss how this is physically possible.

  84. I have argued on Climate Etc several times that the IPCC conclusion on the share of AGW is supported by the evidence, but then I have considered that conclusion as an input to decision making. What we can extract from science to decision making goes like that.

    The questions of climate science itself are somewhat different. That might allow for other and somewhat conflicting descriptions of the issue.

  85. Pekka,

    The questions of climate science itself are somewhat different. That might allow for other and somewhat conflicting descriptions of the issue.

    I don’t quite understand what you mean. My point is that if you’re going to suggest something that appears to violate some fundamental physics, either show that it doesn’t, or show that the physics is wrong.

  86. Fundamental physics tells only so much about climate. Oceans are a badly known part of the Earth system. Many phenomena related to oceans persist for decades, some might persist for longer. What’s going on in oceans is a scientific question that cannot be answered properly.

    When the question is asked in the typically scientific fashion on the behavior of the oceans it cannot be answered well.

    The question about climate change is very different. It starts from the knowledge that CO2 is increasing and that CO2 causes warming. Then it’s asked, how strong is that warming. That’s asked without regard on, what else is going on. Various evidence is looked at from the point of view of this single question. The approach is (or at least should be) Bayesian. The general agreement of the warming of recent decades supports certain values of the TCR. Paleoclimatic studies add their support, and so do climate models. Furthermore policy is not dependent on high level of certainty, but should be essentially the same with quite a lot uncertainty on the lower side as without.

  87. Pekka,
    Yes, I agree, but my point was much simpler.

    Many phenomena related to oceans persist for decades, some might persist for longer. What’s going on in oceans is a scientific question that cannot be answered properly.

    Even so, if the surface temperature is above equilibrium, we should lose the excess energy quickly. If an increased temperature is to persist, it would normally require a change in radiative forcing. I guess there is a chance that the oceans can continue to resupply the energy as it’s lost, but that – too – seems quite implausible. So, although I agree that there is much we don’t understand, I still think there are some basic checks that one can make using basic physics to see if an idea is plausible or not.

  88. BBD says:

    If there is a net flux of energy from the oceans to the atmosphere, OHC should be falling. It is rising.

  89. BBD,
    Indeed, that would be another simple test that one could apply. Again, basic physics – energy conservation.

  90. Heat capacity of the atmosphere is less than that of 5 m of water. There cannot be much heat transfer from oceans to the atmosphere, when changes at TOA are excluded.

    That’s perhaps not a fair comparison, as the atmosphere should perhaps be combined with a layer of surface ocean and compared with the rest of ocean mass.

    Qualitative arguments of this type are not sufficient, more quantitative calculations are needed. The coverage of the empirical data is also insufficient for answering many of the questions.

    I feel that I must repeat that I’m not arguing against IPCC estimates of strength of AGW, but on the state of the scientific understanding of the dynamics of the Earth system on multidecadal time scale. These issues are related but not so strongly that the rate of warming could not be estimated while the further scientific knowledge is lacking.

  91. Pekka,

    Heat capacity of the atmosphere is less than that of 5 m of water. There cannot be much heat transfer from oceans to the atmosphere, when changes at TOA are excluded.

    Yes, that’s what I thought I was suggesting. There can be heat transfer, but the energy won’t stay for long.

    Qualitative arguments of this type are not sufficient, more quantitative calculations are needed.

    I think we’re probably talking slightly at crossed purposes. If anything, I would argue that without an attempt at some physical mechanism, stadium-wave like ideas are largely qualitative. I’m suggesting that one can do some basic (and quantitative) calculations to assess if some analysis makes sense.

  92. ATTP,
    You speculate that one can do some quantitative calculations assess an analysis. Have you done that? Do you know, how much such an assessment can tell without additional assumptions that have little solid support.

    The case seems to be that we have a different view on, how much such an assessment can tell.

    I haven’t done any serious attempts of such an analysis either, but perhaps the evidence should be presented by the one who believes that it works.

  93. Pekka,
    Okay, I think we’re kind of getting into a discussion where we’re talking at cross purposes. You said,

    Heat capacity of the atmosphere is less than that of 5 m of water. There cannot be much heat transfer from oceans to the atmosphere, when changes at TOA are excluded.

    I agree, and this is what I was trying to get at in the first place. If someone is going to argue that some kind of internal variability can produce long-term warming, then I would expect them to attempt to explain how this variability can influence the radiative forcing. I can do a basic calculation that shows (as you’ve implied here) that simply heating the surface and atmosphere is not likely to produce long-term warming because of the low heat content of the system. Similarly, BBD has pointed out that if you want internal variability in the oceans to be warming the surface, you’d expect the OHC to be dropping, not rising. So, all I’m really suggesting is that one can do some basic things to check if a particular idea makes physical sense. I’m not seeing this as being particularly controversial and I’ve become rather confused as to what you’re actually suggesting.

  94. ATTP,

    The ocean is the only part of the Earth system that has a sufficient heat capacity to drive multidecadal variability. For that we need appropriate dynamic properties of both storage capacity and persistence of states. Oceans satisfy those requirements. Significant variability is known to exist and something more may be unknown. These are not totally wild guesses, at least the orders of magnitude are right.

    A lot is going on in the oceans, and much of that is variable. That far we know for sure. We also know that the observed properties of the oceans cannot be explained by models. All this is factual.

    Who can tell, why we have had the unusual state of the equatorial pacific over the latest decade. Scientific papers have proposed that the plateau might be due to upwelling of cold water in Eastern Equatorial Pacific, and there are many other papers related to AMO, PDO, AOC etc by respected scientists. These effects are an a comparable scale.

    We have important poorly known phenomena. As long as they are not better known, the dynamics of the oceans cannot be considered understood.

  95. Pekka,

    Significant variability is known to exist and something more may be unknown. These are not totally wild guesses, at least the orders of magnitude are right.

    I’m not disputing this. I’m simply trying to point out that it if one wants to suggest that this could drive long-term warming then one would need to try and explain how this variability can influence the radiative forcings. I fail to see how this is a particularly controversial suggestion.

  96. ATTP,
    Oceans can certainly not drive really long term warming, but telling where’s the limit is a quantitative question. To answer that question the dynamics of the oceans must be known on the relevant time scales. The measurements of OHC set additional constraints, but the coverage of those measurements may be insufficient. The power of simple energy balance arguments is rather weak. At some point they can give answers, but just guessing, what’s the point is not sufficient.

    I like the approach of going through simple physics based arguments, but my experience has so far been that they are not sufficient for many final conclusions. More detailed and realistic models are needed for that, and we know that the models have their own limitations and uncertainties.

  97. Pekka,
    Yes, I think we’ve essentially agreed. I wasn’t suggesting that it’s easy to quantitatively answer a complex question like that that you’ve posed. I was suggesting it may be straightforward to quantitatively show when a question is ill-posed or when a suggestion is unlikely to be physically plausible.

  98. BBD says:


    Do you think the MCA was a consequence of internal variability?

  99. BBD,
    I don’t have any strong opinions on what really is internal variability. What I have argued about is that we don’t know enough about that. If we would know more about internal variability we would know also more accurately what’s the climate sensitivity.

    My impression is that the whole climate history of the last 2000 years is not understood well at all. I don’t know about realistic estimates on the maximal plausible internal variability on the time scale of a few hundreds years. Perhaps some ocean modes may persist that long and have such an influence, I really don’t know. Volcanism has evidently contributed something, but is that enough? These are questions whose understanding might be valuable as it might help also on projecting to the future.

  100. BBD says:


    If we would know more about internal variability we would know also more accurately what’s the climate sensitivity.

    Reading this inevitably reminded me of Kyle Swanson’s remarks at RC:

    It first needs to be emphasized that natural variability and radiatively forced warming are not competing in some no-holds barred scientific smack down as explanations for the behavior of the global mean temperature over the past century. Both certainly played a role in the evolution of the temperature trajectory over the 20th century, and significant issues remain to be resolved about their relative importance. However, the salient point, one that is oftentimes not clear in arguments about variability in the climate system, is that all else being equal, climate variability and climate sensitivity are flip sides of the same coin. (see also the post Natural Variability and Climate Sensitivity)

    A climate that is highly sensitive to radiative forcing (i.e., responds very strongly to increasing greenhouse gas forcing) by definition will be unable to quickly dissipate global mean temperature anomalies arising from either purely natural dynamical processes or stochastic radiative forcing, and hence will have significant internal variability. The opposite also holds. It’s painfully easy to paint oneself logically into a corner by arguing that either (i) vigorous natural variability caused 20th century climate change, but the climate is insensitive to radiative forcing by greenhouse gases; or (ii) the climate is very sensitive to greenhouse gases, but we still are able to attribute details of inter-decadal wiggles in the global mean temperature to a specific forcing cause. Of course, both could be wrong if the climate is not behaving as a linear forced (stochastic + GHG) system.

  101. BBD,

    Of course, both could be wrong if the climate is not behaving as a linear forced (stochastic + GHG) system.

    I guess this would be interesting if possible, but it does seem unlikely. Not that it shouldn’t be considered, of course,

  102. I restate in a few words, the idea that I have tried to defend:

    1) For the strength of AGW the estimates presented by IPCC are justified. IPCC tells also what else is known about the effects of AGW. Climate policy should be based on the best existing knowledge described well enough by IPCC. Climate policies are basically AGW policies, but preparing against damages from extreme weather has also benefits independent of AGW.

    2) For climate science itself there are many open questions worth studying. Speculating on what this research might reveal should not affect much the discussion on climate policies. Only when the best scientific understanding actually changes, must that be considered also in the policy process.

  103. Pekka,
    I agree. I certainly wasn’t intending to argue against those points.

  104. Pingback: Another Week of Climate Disruption News, April 27, 2014 – A Few Things Ill Considered

  105. John Mashey says:

    Neither the MCA nor the LIA were wholly natural, see Bill Rudidman’s AGU 2014 Tyndall Lecture. or even better, the book. I think evidence has accumulated enough to say Earth’s climate has not been entirely natural for 8,000 years, and I think Bill has pretty good explanations for some of the century/multi-decadal-scale jiggles of the last 2,000 years.

  106. Steve Bloom says:

    Pekka, the difficulty with your first point is that as stated it’s a formula for being bitten by unknown knowns and especially unknown unknowns.

  107. John,
    I have read some of Ruddiman’s articles. He presents interesting hypotheses and presents some evidence to support them, but far too little to convince me. Many major questions are left fully open. My reading of AR5 references to his work tell me that IPCC authors have similar views.

  108. Steve,
    Again I have no idea of what you mean by your sentence.

  109. Steve Bloom says:

    Pekka, my problem with the WG1 Pliocene SLR figure is right there in the passages you quote. If the PLIOMAX range goes up to 31 meters, what’s the basis for WG1 cutting it off with high confidence at 20 meters? Looking at the referenced studies, my conclusion is that it was an effort to make the ice sheet models look less bad.

    Thanks BTW for the pointer to the new Rohling et al. paper, which I had missed. I’ve requested a copy.

    BBD, WG1 didn’t cite Rowley et al. 2012. Possibly it wasn’t available by the deadline, but in any case it doesn’t seem to have been used to support their analysis.

  110. Steve Bloom says:

    Sorry to have waxed Rumsfeldian on you, Pekka. 🙂

    “Climate policy should be based on the best existing knowledge described well enough by IPCC.”

    Until such time as we’re confident we have a good handle on the behavior of the climate system, it’s likely that we will keep finding new aspects that will (or should) inform policy. A good post-AR5 example of this is permafrost melt, which based on a number of recent papers looks to be much worse. Another is ice sheet response. The best policy will make room for such things.

  111. BBD says:


    I think the point is that once the Orangeburg Scarp is reinterpreted taking uplift into account, it sets an upper bound on mid-Pliocene MSL highstands that is *lower* than the IPCC upper bound.

    It looks like the EAIS may have contributed less than the dynamicists (eg. Francis and Hill) argue, and that the stabilists (eg. Denton) are more correct.

    * * *

    Full pdf of Foster & Rohling (2013) here.

  112. BBD says:

    Sorry – I should have said that it’s possible that this is a trend in expert opinion that informed the IPCC’s high confidence in ~20m MSL highstand.

  113. BBD says:


    See also Chandan & Peltier (2014 EGU paper abstract):

    Our analysis suggests that the entire [Orangeburg] scarp has undergone significant and continuing uplift since its formation. After correcting field observations of the present scarp height for dynamic uplift, we find that the sea-level during mid-Pliocene time was no higher than 12-14m above the present level. This estimate is within the error bounds of Miller et al (2012) and implies the complete absence of the Greenland ice-sheet (known not to exist at that time), as well as the West Antarctic ice-sheet, which is understood to be very unstable. Furthermore
    our results imply no significant mass loss for the East Antarctic ice-sheet during the mid-Pliocene. Our analysis differs significantly from that of Rowley, in that the magnitude of the correction required for the degree of present day glacial isostatic disequilibrium is entirely insignificant.

    Which supports Rowley (2013)’s results but applies a different methodology. This is suggestive that different lines of evidence are converging and it looks increasingly as though the stabilists were more correct than the dynamicists.

    Also have a look at Rovere et al. (2014) which supports a MPWP MSL of <20m.

  114. Steve,

    I picked these two paragraphs thinking that allows for concluding:

    1) It’s possible to find support for two ranges of values (in particular for the upper limit).
    2) IPCC authors are well aware of that and present their conclusion on that background.

    PLIOMAX results are clearly consistent also with a lower upper limit, if that is supported by some information not part of the PLIOMAX analysis.

    It’s impossible for me to judge the objectivity or proper balance of views presented in the AR5. I do, however, have the general attitude that good and well supported arguments are needed to present claims of significant bias in the conclusions of IPCC AR5 WG1 main report. I wondered, whether you can present such arguments.

    I looked at the comments presented on the 2nd order draft and found this

    Comment text: Miller et al 2012 are being misrepresented by the statement that MPWP peak sea level estimates “range widely (5-40 m) (Miller et al., 2012”. They present data and an error analysis from which they conclude that it is extremely likely peak sea levels lay in the range 12 to 32 m above present (see abstract). Their data comprise 33 sets from 9 separate highstands between 2.74 and 3.20 Ma. 13 sets come from field-based estimates from NZ, Enewetak Atoll and Virginia, thus widely spread but subject to GIA uncertainties, and 20 sets are based on joint Mg/δ18O analyses that are not. The mean sea level estimates range from 9.3 to 22.3 m; the younger 6 range from 9 to 15 m (SD ranging from 3 to 13 m) and the older 3 range from 21 to 22 m (SD ranging from 3 to 5 m). Section 5.6.1 begins with the words “Estimates of peak sea levels during the MPWP based on a variety of geological records are consistent in suggesting higher than present sea levels,..” You might continue with words like “Miller et al. (2012) have reported that the highest three of these (3.07, 3.16 and 3.20 Ma) lie around 21+5m above present sea level, but they also noted that benthic foraminiferal δ18O values provided an upper limit of ~21 m”. [Peter Barrett, New Zealand]

    The authors responded

    Taken into account in the revised MPWP sea level section.

    The earlier formulation was weaker, but seems to explain better the logic.

    In summary, there are multiple lines of evidence that global mean sea level during MPWP was higher than today, but low agreement on how high it reached. The most robust lines of evidence come from proximal sedimentary records that suggest periodic deglaciation of the WAIS (Naish et al., 2009a) and from ice-sheet models that suggest near-complete deglaciation of GIS, WAIS and some contribution from the EAIS. We have therefore medium confidence that sea level was 10 ± 10 m above present during the warmest periods of the Pliocene, with an uncertainty that brackets the range of most estimates from various methods. We have low confidence that sea level was more than 20 m above present.

    The number of rounds of the IPCC process is not sufficient for allowing the final formulation to be subjected to open commenting. Changes made based on a comment on SOD might well lead to further comments from somebody else, but the authors know that, and should take that into account.

    Another problem is the limitation on the allowed length of the chapters. That makes it impossible to present many clarifying explanations and may be the reason for the shortness of the final summarizing paragraph. The preceding longer paragraph present references to original research, but is difficult to interpret without digging into those.

    IPCC WG1 reports are good lists to original research, but many chapters are barely intelligible to non-specialists by themselves. That’s one reason for my view that it’s time to find a new approach. A database of publications with assessment could be maintained on a continuous basis, and state of art summaries written as separate tasks emphasizing readability more, but keeping still within the science itself as opposed to more general summary reports. (How such state of art summaries would differ from normal textbooks is a further question:)

  115. Steve Bloom says:

    Maybe re expert opinion, BBD, but if so I would have expected that to be reflected in the current PLIOMAX estimate. TBC I’m fine with 20 meters as a central estimate; it’s the lopped-off upper part of the range I’m questioning.

    F+R 2013 has 22 +13/-12 meters for the Pliocene. TBC Pekka was quoting from a different, more recent paper. F+R seem to place an upper limit of 10 meters on a possible EAIS contribution, but IIRC some very recent work has pointed to the possibility of more than that.

    The Orangeburg Scarp seems especially tricky given how much it’s moved. But there are other scarps to be analyzed, and the new Rohling et al. paper, based on a completely new (and very striking-looking) Mediterranean location, sounds very interesting.

    See also this new paper discussing the scarps. Note that MR is second author (first was her post-doc). Their upshot is “we might infer that a Pliocene ESL <20 m is the most consistent with data" but that remains a much weaker statement than WG1.

  116. Steve Bloom says:

    Pekka, that exchange does not bolster confidence in the process. 10 +/-10 meters is absurd given the indisputable GIS and WAIS melt. Who was allowed to get close enough to the draft to write such a thing?

    I agree entirely with your comments about the limitations of the current process, but I don’t think they excuse the error.

  117. BBD says:


    TBC Pekka was quoting from a different, more recent paper.

    So he was. Sorry and thanks for the article link. Looks interesting, but then Rohling’s work is always interesting. Re: “striking looking location” – yes, the 41ka obliquity cycle that can control sedimentation but not (in combination with precession and eccentricity) trigger deglaciations, according to some, but not, you may be sure, to me…

    See also this new paper discussing the scarps.

    I think that’s Rovere et al. (see link at end of my previous). We are both doing it today 😉

    TBC I’m fine with 20 meters as a central estimate; it’s the lopped-off upper part of the range I’m questioning.

    I can only follow the unfolding scientific exploration, not question it. Don’t know enough. If the experts seem to be saying that ~20m is looking more likely to be the upper bound for MPWP MSL, then so be it.

  118. BBD says:

    Pekka, that exchange does not bolster confidence in the process. 10 +/-10 meters is absurd given the indisputable GIS and WAIS melt.

    Agreed – this is, as they say, bizarre.

  119. Steve Bloom says:

    BBD, how does the C+P abstract support Rowley (2013)? The latter point to +25 meters, although with big caveats. Did you mean it supports Miller (2012)?

    Also, C+P say their results are “within the error bounds of Miller et al (2012)” but that’s a thin, thin claim (taking 14 meters as their upper limit).

    As a general matter, based on today’s reading I’m prepared to discount almost any results based solely on the Orangeburg scarp.

  120. BBD says:


    I haven’t been entirely clear. What I should have written is that all the recent work incorporating improved tectonic corrections is pointing to a MPWP MSL of ~20m or less and away from values above ~20m. Which is presumably why AR5 is favouring ~20m as the upper bound.

    Earlier you said:

    I’m fine with 20 meters as a central estimate; it’s the lopped-off upper part of the range I’m questioning.

    The preceding comments were simply an attempt to answer that question.

  121. Steve Bloom says:

    Sure, BBD, I understand your general point but, but I just don’t see enough justification for that in the literature.

    I’ll repeat that the evidence we have from the drafting process is that 20 meters was selected as the upper bound because someone(s) thought 10 meters was a good central estimate and 0 is as plausible as 20. To me that looks like an attempt to get a central estimate within the upper error bar of the cited DeConto+Pollard (2009) ice sheet modeling paper (which IIRC they don’t think is valid any longer because of the lack of EAIS melt — I’ll see if I can track down that reference).

    I just got the new Rohling et al. paper, so more on that later. Did you see in the abstract where they assert that all of the d18O-based results are questionable? If so, that’s quite a monkey wrench in the gears.

  122. BBD says:


    Sure, BBD, I understand your general point but, but I just don’t see enough justification for that in the literature.

    Well, let’s see what the next year or two brings. I suspect we will see a further convergence on ~20m but time will tell. You may be right about what you say wrt AR5 and DeConto & Pollard09, but I am reluctant to speculate about that.

    What is clear is that there *is* evidence for localised EAIS instability during the early-mid Pliocence – see Cook et al. (2013) (was this what you had in mind?).

    I have no problem at all with a composite picture of no GIS, complete WAIS collapse and several metres additional contribution from areas of the EAIS like the Wilkes Subglacial Basin. I’d be rather more surprised if there were *no* contribution from the EAIS, which seems implausible.

    * * *

    Did you see in the abstract where they assert that all of the d18O-based results are questionable? If so, that’s quite a monkey wrench in the gears.

    I’m not sure that Rohling et al. made quite so strong a statement but you have the paper and I don’t, so please say more when you have had a chance to look through it.

  123. Steve Bloom says:

    Cook et al. is one, but there’s another I have to find that IIRC points to another major chunk of the EAIS (the bit immediately east of the WAIS) as being vulnerable to loss at a relatively low level of warming, although as yet there are no sediment cores available.

    Cook et al. having been submitted in January 2013, it seems like the WG1 authors would have known about it before finalizing the text.

    Anyway, they get 10 meters for Wilkes Land (media quote from the lead author, not the paper, so I don’t know what the error bars are), which puts things at no less than 22 meters even if no other part of the EAIS had significant loss.

    Four in-prep follow-up papers are noted, which Cook expects to shed light on the speed of the ice sheet loss, so this will only get more interesting.

    I’ll wade into Rohling et al. this evening. It looks to be thick going.

  124. BBD says:

    It’s good for the soul, Steve.


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