David’s Dirty Hippies

David Roberts, who has gotten a lot of leftie blogosphere traction with his dirty hippie post, is at it again.

Here’s David, describing the point he made on a conservative talk show (“one of the B-list Limbaughs”) yesterday:

The IPCC is one of the most rigorous scientific processes ever developed, and its new report pegs it at greater than 90% confidence that humanity is driving recent warming.

Here’s David a couple of weeks back defending his willingness to abandon the consensus:

Yes, we have to leave science to the scientists. But science is not a priesthood that can or should impose quietude on the rest of us. Our informed gut feelings about how things will turn out are legitimate. People make statements beyond what’s strictly supported by the peer-reviewed evidence all the time. For some reason, internet wonks seem to hold public advocacy on global warming to a strangely prudish set of standards. We don’t impose these kinds of strictures in other areas.

Hey, what if my gut tells me that the effect of solar variability is greater than the climate models suggest, or that land use changes are really a bigger player than acknowledged (both of which, like hurricanes, are areas where the major consensus documents acknowledge significant uncertainties)?
As soon as one endorses one’s “gut feelings about how things will turn out,” then Katy bar the door. The entire nature of the scientized public debate on these questions (climate change, genetically modified foods, radiation risks) is that public advocates follow their gut rather than the scientific consensus. As Dan Sarewitz explains, that’s to be expected, and is what creates gridlock on these issues.

But Roberts, as a journalist, has a different obligation than ordinary advocates – even more because of the sort of advocacy journalism he does. Grist as a whole has a tendency to feed its audience’s biases, but that is precisely what Roberts should not do on questions like this. This is one of those climate science questions where reasonable scientists have a genuine disagreement, and for Roberts to pick sides is to ignore his obligation to explain to Grist readers the nature of that genuine disagreement and its implications.

As I’ve written elsewhere about journalists’ obligations:

Here’s what you should expect from us, as a smart consumer of news, but also as an attentive citizen. You should expect us to explain what’s reasonable about your opponents’ arguments. You already know your own arguments. You don’t need us to help you there. You need us to help you listen to the people on the other side of the debate. (And of course, you should expect us to present your arguments well to the other side.) And people who aren’t on either side should expect to get an explanation of both sides’ positions.

I don’t expect Roberts to do the same thing at Grist that I do in a mainstream newspaper. But I what I also don’t expect of him is to, in his words, “ally ourselves with respected scientists like Kerry Emanuel and Tom Wigley who believe there is a strong connection between hurricanes and climate change” without also explaining to Grist readers why equally respected scientists on the opposite side of the hurricane issue have come to different conclusions.

If all Roberts is doing as a journalist is feeding his readers’ biases, and his own, there’s frankly not much point. He’s obviously talented and passionate, and he has a terrific audience that would be better served by good science journalism than cheap advocacy, which is why I expect better.


  1. Let’s see, John: Emanuel, Holland, Webster, Wigley, Trenberth, Anthes, Knutson etc. So who exactly are the “equally respected scientists on the opposite side of the hurricane issue”? Is there anything like a similar list? Any way you look at it (cvs, Rossby Medal count, etc.), this is not even close to an even split.

    Regarding your main point, here’s my two cents: The consensus states that there’s a range of responsiveness to AGW (dependent on sensitivity and the course of further emissions). The low end arguably would not result in dangerous climate change, while the high end would. Looking at this range of outcomes, I think an intelligent lay person can review the science and decide that the high end is far more likely than the low end. I think David has that perspective, and I think it’s entirely defensible. Obviously he should still make reference to the uncertainty, but I think he does so sufficiently.

  2. BTW, I noticed that David’s “informed gut” somehow became just plain gut. Did you assume thet “informed” had no meaning?

  3. Steve -

    The participants in the World Meteorological Organization’s 6th International Workshop on Tropical Cyclones – including Emanuel and Holland, who chaired the committee whose work led to this statement: “A consensus of 125 of the world’s leading tropical cyclone researchers and forecasters says that no firm link can yet be drawn between human-induced climate change and variations in the intensity and frequency of tropical cyclones.”

    I mean, really, don’t you think if someone on the other side was making an argument so obviously at odds with such a clear consensus statement, y’all would be all over them? I just don’t get why y’all won’t acknowledge the fundamental intellectual inconsistency here. And, obviously per my comments above, I think it’s especially egregious of David, whose position as a journalist imposes special obligations.

  4. “Looking at this range of outcomes, I think an intelligent lay person can review the science and decide that the high end is far more likely than the low end.”

    Depends what you mean by high end versus low end, but if you assume that the presentation is intended to be an unbiased one according to the approximate consensus of a large number of experts then your “intelligent lay person” is simply claiming that these experts are all wrong, with no apparent justification for such an assertion.

    If someone puts up some argument as to why the science is wrong, that’s another matter entirely. Most likely such a person would be a scientist with some demonstrated understanding of the area, although in principle anyone could do it. Even so, I’d not expect policy-makers to pay much attention until the bulk of the scientists are convinced.

  5. James, IMHO the science isn’t wrong, it’s incomplete. I have no disagreement with the view that given present knowledge 3C or so is the most likely sensitivity, but I also believe there is a reasonable basis to think that “known unknowns” (sink saturation, permafrost melt, etc.) will tend to cause the sensitivity range (and thus its mid-point) to be revised upward. Aren’t there plenty of climate scientists who hold this view? Of course the foregoing just winds up in a debate over what amounts to speculation, so for myself I prefer to simply argue that the consequences of business as usual given even mid-range sensitivity present an unacceptable risk. Nonetheless I think the first view is entirely legitimate.

  6. Aha, John, you shifted the ground. I was just responding to your “equally respected scientists on the opposite side” remark. Now you’re saying that the WMO statement shows that there aren’t two sides, or rather that everyone who signed it is on one side?

    I seem to recall an identical discussion over last year’s WMO statement (either with you or Chris Mooney). I described it at the time as something like a temporary papering-over of disagreements until after the next round of papers. Jeez was I right about that. This latest one is more of the same. But don’t just take my word for it: Judy Curry (very much an insider on this debate) responded here that “it is premature to accept the WMO statement as any kind of a broad consensus on this subject.”

  7. Clarification re my response to James: I keep forgetting that carbon feedbacks aren’t included in sensitivity, and IIRC both of the factors I mentioned are carbon feedbacks (and so would have the effect of increasing actual warming even if the sensitivity range remains unchanged.)

  8. “people who aren’t on either side should expect to get an explanation of both sides’ positions.” — J Fleck

    Not if one side is clearly wrong.

    When it comes to the geology of the earth, should we expect to get an explanation of the Flat Earther’s position?

    This is the same tired “balance” argument that we hear so often. It has no place in science journalism — period.

    “You need us to help you listen to the people on the other side of the debate.”

    You who? Why does a scientist, engineer or anyone else who knows something about science need a journalist (who may know very little) to help him/her listen to the other side?

    Chances are good that anything that is understandable to a journalist with no formal training in science is probably also within the grasp of most intelligent people — particualrly to those who do have formal education in the sciences.

    Intelligent people can do their own research and make their own decisions about whom they should listen to.

  9. Steve -

    You already know who the scientists are on the other side, and you’ve read their work, and you’ve decided who’s right and who’s wrong, and you’re trying to drag me into a scientized debate. I won’t go there. I’ve already explained my view of the role of expert panels in determining the state of the science on contested questions, and you’ve expressed yours, and a debate over people’s cv’s seems a priori pointless given that we’ve got an expert panel statement to go on.

    I repeat my astonishment at your willingness to engage in *precisely* the rhetorical tactic that you so rightly criticize your opponents for – invoking outliers in the face of a clearly articulated consensus.

  10. LJ -

    We’re not talking about flat earthers, or people who deny evolution. I give no credence to people who are, as you so knowingly put it, “clearly wrong.” I have a long and public body of work. If you think I’m giving undue credence to people who are “clearly wrong,” please cite some examples. We’re talking about scientists publishing in the peer reviewed literature, where the scientific discussion is rich and robust. At the risk of repeating my labored words over on Grist, let me cut and paste my explanation of what I think my journalist’s responsibility is by invoking scientists I believe are nibbling interestingly at the edges of the consensus.

    The first would be Roger Pielke Sr., whose continued niggling on the effects of land use changes has my attention. The consensus, as expressed by the IPCC and NAS reports, suggests that the effect is probably negligible enough relative to greenhouse forcing as to be ignorable for policy purposes. But the consensus also clearly acknowledges significant uncertainty, leaving room for interesting discussion.

    The second would be Kerry Emanuel, whose hurricane work has my attention. The consensus, as expressed by the IPCC and more recently the WMO, suggests that the effect is probably negligible enough relative to other climate change problems as to be ignorable for policy purposes. But the consensus also clearly acknowledges significant uncertainty, leaving room for interesting discussion.

    The literature is regularly full of examples like this: James Annan’s work suggesting upper limits on climate sensitivity (OK, it’s not in the literature, but I’m willing to treat it like it is); Petr Chylek’s work questioning the Greenland temperature trend; the various teams reporting accelerating Greenland ice cap melting; the Mann, Cane, Zebiak, Clement work raising the possibility of serious drought where I live because of climate change; Marty Hoerling’s amazing paper using the IPCC climate runs to suggest dramatic decreases in Colorado River flow over the next century (eek!); the various analyses suggesting more El Ninos and therefore greater southwest precipitation.

    Those that are of relevance to my audience (New Mexicans), I write about, trying to explain both what the new research suggests, and how it fits into or conflicts with the consensus. When the new work suggests things will be “worse than we thought,” I get beat up by the “Limbaugh hordes”. When the new works suggests things will be “not as bad as we thought,” I get beat up by the “dirty hippies”. This is the classic response one would expect based on the work of Sarewitz – that people with strongly held views on a subject will pick and choose among the science, tending to believe that which supports their views and dismissing that which conflicts. Journalism isn’t much good in reaching those people. Instead, I’m hoping to communicate to those in fat middle of the bell curve of public opinion, helping those who chose to actually read the work to better understand what the science actually says.

    There’s good evidence from the literature on the public understanding of science that what I’m attempting here is futile, that the “cognitive misers” out there won’t take the time to seriously read about the science, instead taking their cues from the various opinion leaders. But I’m in denial about that, as I’ve got no other marketable skills.

  11. Steve-the problem is that if you’re going to put that entire group on one side, I’m not what that side is and why you’re excluding other people. A primary question seems to be how far back the observational database can be used to look for temporal changes in number and intensity in the North Atlantic. (Wu et al (2006) in EOS seem to have rather definitively shown that trends can’t be detected in PDI or ACE or fraction of major hurricanes in the Western North Pacific by using the three different best track databases that exist and finding different signs of the trends depending on which database is used.) Holland believes the Webster et al. conclusions are robust with respect to the best track data back to the beginning of 20th century. Emanuel doesn’t think the data can be trusted before 1958. Knutson seems to agree with Landsea that the data are of insufficient quality to draw conclusions on trends.

    Knutson and Tuleya’s work has suggested a ~5% increase in maximum winds for a 1-2 C SST increase, which Webster et al. apparently don’t agree with, given that their 2005 paper suggested an increase about 8X that. Landsea, on the other hand, would much more closely agree with Knutson and Tuleya.

    If you’re going to throw a net wide enough to include Holland and Knutson on one “side”, Landsea’s on that side as well. The only person who might not be is Bill Gray.

    My take is that there’s no one on your list, with the exception of Knutson and Emanuel, who appreciate the difficulties of working with the best track data prior to the satellite era. (Emanuel got around it by explicitly choosing not to use it.) At the AMS meeting last week, Holland seemed to be invoking changes in the locations of formation of tropical cyclones in the North Atlantic that took place at the same time as the biggest changes in the dataset collection (beginning of aircraft recon and satellite observation). Landsea showed that the fraction of reported North Atlantic storms that made landfall or near landfall (within 60 mi) has been relatively consistent during the satellite era (~58%). Prior to aircraft recon, that fraction is in the 80s%, with several years having all storms in the landfall/near-landfall category (the highest since satellite has been 70%). To me, it would be a remarkable coincidence to argue that the location of formation changed, so that the fraction of landfalls changed, at the same time as the reporting system had a big change. Landsea showed that, if you assume the satellite era fraction should have held in the pre-recon era, that would lead to an average of 3-4 more named storms per year in the pre-recon. The satellite era mean has been 10.6 per year, so the addition of 3-4 in the old days dramatically reduces any trend. That doesn’t take into account the tropical storm per year from 2001-2005 identified in the record based on technology not available in the analysis in 1999 (e.g., QuikScat and the AMSU temperature sensor).

  12. “We’re not talking about flat earthers, or people who deny evolution.”

    I am not familiar with what you have written, but I will remark that there have been those who have denied any significant AGW — in direct conflict with the IPCC scientific consensus — and some of these have been given positive exposure (sometimes even equal time) by “journalists” writing about the issue.

    My main point was that when a journalist decides to present “both (or all) sides” of an issue, he/she may be presenting ideas that have been rejected by most scientists. This does the public no favors.

    If the IPCC says something about AGW, science journalists should report that (and only after they have said it, not before — All this speculation on blogs and elswhere about what the soon-to-be-released IPCC report is going to say is just unmittigated rubbish.)

    Journalists should be very careful about reporting claims that conflict with the scientific consensus for the simple reason that journalists are usually not in the best position to decide whether such claims are accurate.

    You may not be, but some journalists are guilty of creating (sometimes unwittingly) the false appearance of an equivalence between opposing scientific claims when there is no such equivalence (indeed, not even close to an equivalence).

  13. LJ -

    “Journalists should be very careful about reporting claims that conflict with the scientific consensus for the simple reason that journalists are usually not in the best position to decide whether such claims are accurate.” That is exactly what I have been trying to say all along. The trigger for this entire discussion was David Roberts’ defense of those in the political arena who argue for a global warming-hurricane link, an argument which is conflict with the current scientific consensus on the issue.

  14. John, I appreciate your statement of a journalist’s [ideal] modus operandus (which I hadn’t read before). Even if the media talked about something where I might be an expert, my ears are still open. Science and engineering – particularly the flavours I practice – don’t operate exclusively in technical circles. The thrust of my personal technical interests are driven by social needs, and the media is one of the avenues of hearing these needs. Furthermore, journalists are more prolific writers than me, and I can learn a lot from how they mould concepts and compose a narrative. For example, among other things I’m a modeler, and Andy Revkin once compared climate models to impressionistic paintings. That’s an excellent analogy, and one that I have built on in my technical presentations.

  15. The problem with Sr’s land use obsession is twofold. First, two thirds of the earth is water, and there is not much land being used there, incresingly less.** Second, he only looks at one side of the ledger. In this he suffers from a disease caught by his co-authors Michaels, Knappenberger and Landsea

    **Indeed if you look carefully, even on the remaining third there is not that much change, and what there is forces the climate pretty much here, but then there.

  16. Eli, land use change (of which there has been plenty on the remaining third) has a significant effect on climate, but we know far too little about the linkages. Whether it plays as significant a role as RP Sr cliams is another matter.

    Two quick examples of non-C02 forcings on regional climate change (from authors other than RPSr, even though Marland et al., Climate Policy, 2003 is satisfactory review): Chagnon and Bras, GRL, 2005; Gordon et al., PNAS, 2005. Furthermore, what of talk about potential feedback in the form of diminished snow/ice and subsequent drop in albedo? This is a type of effect land use change can have. Then comes the CO2 forcings of land use change – changes in the stores of C in above/belowground biomass.

    We really don’t know enough about how these factors add up. Perhaps your footnote was to suggest that regional changes average themselves out – I would find that surprising.

  17. John:

    Perhaps I focussed too much on your statement of “journalist’s obligations” which does not seem to be entirely consistent with your call to report the consensus (and looks more than a little like the old “journalistic balance” argument”).

    My mistake.

  18. John, regarding RP Sr., you are way less obtuse than he is, so who can say where the balance is struck?

    I’d have a little more respect for him if he devoted less time to dodging questions about his assertions. Most recently, he had criticized a European AGW reduction plan (IIRC) for devoting insufficient attention to land use vs. GHGs. I asked if it could be reasonably asserted that *going into the future* there were steps that could be taken re land use that would mitigate AGW on anything like the same scale as GHG reductions (a question which is quite distinct from the one of the relative contribition of each to current warming). He chose instead to answer a question I hadn’t asked. Eh.

  19. Hi Harold! It’s nice to hear from you. I was thinking of you a couple of weeks ago when that big ice storm was making itself a little too available for analysis by your operation. :) I’m sorry you haven’t been able to comment over at RC lately, but hopefully that will change. In particular, your thoroughness everywhere you comment is much appreciated.

    Just to clarify regarding TCs, my point was not to try to present a full-blown analysis of the current lay of the land of the TC-AGW debate (which I agree can’t be done very well without attending the meetings), but simply to point out that John’s assertion that the WMO statement is very definitive or a consensus at all was incorrect. I think I presented sufficient evidence regarding that.

    As Eli points out, Chris Landsea has staked out a qualitatively different position than Knutson and Webster, even though you’re right that quantitatively it’s a different story. I think Knutson’s web site makes it pretty clear where he stands; i.e., that there is an unresolved discrepancy between KT 2004 and Webster et al (and now some others), which he pointedly does not characterize as likely to be resolved in favor of KT 2004, vs. his characterization of MKL as being completely wrong.

    Regarding the best track data, note that Judy Curry says that her team is doing a lot of work on that now. She says that her grad students have already spotted a number of mistakes in HURDAT, which is interesting considering how recently Landsea considered it reliable (although maybe the caveman business was by way of an apology for that). Judy seems to think that the comprehensive satellite-era re-works will eventually result in some sort of canonical product, although it sounds like the pre-satellite data will always be a problem.

    Back to Knutson, I just now visited his web page for the first time in a while and read this very significant (in my lay opinion) submitted paper. The next iteration of this effort plus the European forecast model results (if they’re ever actually published) should serve to cast a whole lot more light on this subject, since after all the issue of how much of an AGW signal is present in TCs now is really just a proxy for the dispute over how they’re likely to behave over the next decade or two.

  20. I hope to do a back of the envelope about human land use changes soon. I do not doubt that they are large. I do not doubt that there are many different types of land use change. I do doubt that they are uniform (in one direction). I do doubt that they are large as compared to greenhouse gas forcing in the last 50 years, and I have no doubt that they were the major human driver in the 19th century.

    Further, I am not exactly sure how you would characterize albedo changes due to ice disappearing. At first glance it is not a forcing but a response to other forcings such as greenhouse gas and solar.

    I apologize if this appears to be coming on too strong, but just remember John, you are a journalist, I am but a dumb (although cute) bunny.

  21. Steve-If you take the definition of a consensus as being something that the largest number of people can agree to, then the WMO statement is consensus. Probably everyone on the list would want stronger language on something, but this is the common ground.

    Chris Landsea has never thought HURDAT was reliable, although I have to admit I’m not sure what that word means in this context. If he did, he wouldn’t have started the reanalysis project years ago at AOML.

    Jim Kossin’s work on an objective Dvorak analysis of the globe back through the satellite era is probably the best hope for a uniform look at things over that era. I’m not sure how long it will take him to finish, but I believe he’s worked back to ~1990 so far.

  22. Harold, as an outsider to all of this I probably tend to over-emphasize the politics (broad sense) behind things like the WMO statement. I think my reaction to the use of the term “consensus” is the perhaps unintended but nonetheless unavoidable comparison to the IPCC, which I think we can all agree constitutes a whole different level of consensus. Last year’s WMO statement was also promoted as a consensus, but subsequent events showed it to be anything but that. We shall see how this one works out.

    My point about Landsea was that he and others at NHC/HPC considered HURDAT sufficiently reliable to make the natural cycle causation claim included in Goldenson et al (2001). Add to that the poor reaction many of them had (recalling e.g. Landsea’s histrionic IPPC resignation, Goldenson’s public statement that the new work is “voodoo”, and last but not least certain administrative shenanigans such as with this article).

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