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ClimateDialogue: Exploring different views on climate change

Filed under: — group @ 15 November 2012

This is a guest posting from some Dutch colleagues on a new online experiment in fostering dialogue on climate change. Bart Verheggen has asked us to host this quick introduction. We are interested to hear if you think this is a good idea.

Guest Commentary by Bart Strengers (PBL) offers a platform for discussions between invited climate scientists on important climate topics that have been subject to scientific and public debate. The goal of the platform is to explore the full range of views currently held by scientists by inviting experts with different views on the topic of discussion. We encourage the invited scientists to formulate their own personal scientific views; they are not asked to act as representatives for any particular group in the climate debate.

Obviously, there are many excellent blogs that facilitate discussions between climate experts, but as the climate debate is highly polarized and politicized, blog discussions between experts with opposing views are rare.


The discovery, early 2010, of a number of errors in the Fourth IPCC Assessment Report on climate impacts (Working Group II), led to a review of the processes and procedures of the IPCC by the InterAcademy Council (IAC). The IAC-report triggered a debate in the Dutch Parliament about the reliability of climate science in general. Based on the IAC recommendation that ‘the full range of views’ should be covered in the IPCC reports, Parliament asked the Dutch government ‘to also involve climate skeptics in future studies on climate change’.

In response, the Ministry of Infrastructure and the Environment announced a number of projects that are aimed to increase this involvement. is one of these projects.

We are starting ClimateDialogue with a discussion on the causes of the decline of Arctic Sea Ice, and the question to what extent this decline can be explained by global warming. Also, the projected timing of the first year that the Arctic will be ice free will be discussed. With respect to the latter, in its Fourth Assessment Report in 2007, IPCC anticipated that (near) ice free conditions might occur by the end of this century. Since then, several studies have indicated this could be between 2030-2050, or even earlier.

We invited three experts to take part in the discussion: Judith Curry, chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology; Walt Meier, research scientist at the National Snow & Ice Data Center (NSIDC) in Boulder, Colorado; and Ron Lindsay, Senior Principal Physicist at the Polar Science Center of the University of Washington in Seattle.

Future topics that will be discussed include: climate sensitivity, sea level rise, urban heat island-effects, the value of comprehensive climate models, ocean heat storage, and the warming trend over the past few decades.

Our format

Each discussion will be kicked off by a short introduction written by the editorial staff, followed by a guest blog by two or more invited scientists. The scientists will start the discussion by responding to each other’s arguments. It is not the goal of ClimateDialogue to reach a consensus, but to stimulate the discussion and to make clear what the discussants agree or disagree on and why. 
To round off the discussion on a particular topic, the ClimateDialogue editor will write a summary, describing the areas of agreement and disagreement between the discussants. The participants will be asked to approve this final article, the discussion between the experts on that topic will then be closed and the editorial board will open a new discussion on a different topic.

The public (including other climate scientists) are also free to comment, but for practical reasons these comments will be shown separately.

The project organization consists of an editorial staff of three people and an advisory board of seven people, all of whom are based in the Netherlands. The editorial staff is concerned with the day-to-day operation of researching topics, finding participants for the discussion and moderating the discussions between the experts. The main task of the advisory board is to guard the neutrality of the platform and to advise the editorial staff about its activities

The project leader is Rob van Dorland of the Royal Netherlands Meteorological Institute (KNMI), a senior scientist and climate advisor in the Climate Services section and is often active at the interface between science and society. The second member is Bart Strengers. He is a climate policy analyst and modeler in the IMAGE-project at the PBL Netherlands Environmental Assessment Agency (PBL) and has been involved in the discussion with climate skeptics for many years. The third member is Marcel Crok, an investigative science writer, who published a critical book (in Dutch) about the climate debate.

We welcome comments here and are happy to answer any questions regarding this project. You can also send an email to info [at] climatedialogue [dot] org.

282 Responses to “ClimateDialogue: Exploring different views on climate change”

  1. 251
    Toby Thaler says:

    Dan H—(ref: #243, #244, #245, #248)

    This dialogue is absurd:

    1) As flxible points out, in response to me you made another conclusory assertion without citation. And the assertion you made concerns not just Arctic sea ice (“both sea ice and mountain glacier losses are reversible”), which I thought was the sole topic of the CD dialogue at issue here.

    2) When pushed by flxble, you provide a citation to a conference talk (not a published paper as far as I can tell). The abstract for the conference does not support your conclusion; it simply poses the question. And the conference only addressed Greenland ice, not Arctic sea ice.

    3) You assert with minimal (and IMO facile) argument that the cited reference supports your conclusion, and you shouldn’t have to post references since “I was not aware that common knowledge required substantiation”!

    4) Engaging in a dialogue about technical issues without argument or citation to data is absurd enough, but doing so with non-scientists (neither you nor flxble have asserted relevant expertise) is not likely to result in any agreement on highly technical issues worth the electrons they’re printed with. (But that never stopped any of us bloggers before.)

    Nevertheless, I’m a decent policy analyst (and a competent lawyer), and your reference did give me enough to find more relevant material, so I’ll have a go–

    Using as my initial search term the key phrase in the conference title you referenced, “reversibility of Greenland ice sheet melting in a warming climate,” I found one paper with Huybrechts as an author that is directly relevant to the reversibility question, a second paper that is a bit less relevant, and also a summary of the talk he gave at the 2004 conference. Full text of both published papers is readily available at the links included here. To save you the trouble, here are the abstracts of all three items in reverse order with some key phrases in bold:

    MILMO (Modeling the Evolution of Climate and Sea Level over the third Millenium) workshop: Brussels, 16-17 November 2004 – ABSTRACTS
    “Volume changes of the Greenland and Antarctic ice sheets have the potential to significantly increase the rate of global sea-level rise in future warmer climates. Crucial aspects are how climatic changes will affect the ice sheet’s mass balance and how ice dynamics will react to the imposed environmental forcing. This is in addition to the longer-term background trend from adjustments as far back as the last glacial period. These questions are addressed with 3-D thermomechanical ice sheet/ice shelf models which have been fully interactively coupled with climate models of varying complexity. A first series of experiments considers the coupling between models of the Antarctic and Greenland ice sheets with the LOVECLIM model for the period between 1500 and 3000. Whereas changes in the polar ice sheets are found to be small over historic times, important changes are expected for the next 1000 years. It is found that for SRES scenario A2 kept constant after the 21st century, the Greenland ice sheet almost completely disappears within a period of about 1000 years. Together with significant shrinkage of the Antarctic ice sheet and the contributions from mountain glaciers and thermal expansion of the world’s oceans, this may cause a global sea level rise in excess of 10 m by the year 3000. A second series of experiments investigated the issue of reversibility of Greenland ice sheet melting once ice sheet disintegration has been initiated. For that purpose, the Greenland ice sheet model was inserted in the HadCM3 atmosphere-ocean general circulation model. In this experiment, the Greenland ice sheet is found to disintegrate to less than 5% of its current volume within 3000 years under constant 4xCO2 conditions. With the ice sheet removed, the model shows that it would not regrow to its present state for present climate conditions, indicative of hysteresis. It was found that there exists a point-of-no-return once ice sheet disintegration has set in beyond which complete removal of the ice sheet becomes irreversible, even if climatic conditions were to revert to present-day conditions. This point may already be reached after 250 years of ice-sheet melting under a non-extreme greenhouse warming scenario.”

    Toniazzo, T. , Gregory, J. and Huybrechts, P. (2004): Climatic impact of a Greenland deglaciation and its possible irreversibility , Journal of Climate, 17 (1), pp. 21-33
    “Warmer climate conditions persisting for a period of many centuries could lead to the disappearance of the Greenland ice-sheet, with a related 7 m rise in sea-level. We address the question of whether the ice-sheet could be regenerated if pre-industrial climate conditions were re-established after its melting. We use the HadCM3 coupled atmosphere-ocean GCM to simulate the global and regional climate with preindustrial atmospheric greenhouse-gas composition and the Green-land ice-sheet removed. Two separate cases are considered. In one, the surface topography of Greenland is given by that of the bedrock currently buried under the ice-sheet. In the other, a readjustment to isostatic equilibrium of the unloaded orography is taken into account, giving higher elevations. In both cases, there is greater summer melting than in the current climate, leading to partially snow-free summers with much higher temperatures. On the long-term aver-age, there is no accumulation of snow. The implication of this result is that the removal of the Greenland ice-sheet due to a prolonged climatic warming would not be reversible.”

    Ridley, J. , Huybrechts, P. , Gregory, J. and Lowe, J. (2005): Elimination of the Greenland ice sheet in a high-CO2 climate , Journal of Climate, 18(17)3427, 3409
    (I’ve removed this abstract; this paper does not address the reversibility issue.)

    Now I understand why you think CD “is offering useful dialogue to those interested in climate change;” you don’t have a clue about basic research and construction of a logical argument in support of a conclusion. Perhaps you’d like to take the references from this post and put them up at CD and ask Dr. Curry what she thinks of Toniazzo (et al.) and Huybrechts’ analysis and conclusions; they at least impliedly contradict her assertion quoted in my post above. (Conclusions about Greenland are not necessarily applicable to the issue of reversibility of Arctic sea ice loss; please let us know when you find relevant references on the latter.)

  2. 252
    Hank Roberts says:

    > nothing to do with his claim

    Well, he still needs a cite for his step two.

    He points to a paper that says it’s not going to happen,
    and, …
    and proclaims the cite proves it could happen.

    It’s logical if you think about it.

    Except for step two.
    He needs to be a little more explicit there.

  3. 253
    flxible says:

    Thanks for the link Dan H, it’s comforting to know that someone is considering the condition of the GIS 3,000 years hence, but the link[s] required are to your handwaving: “The old line of thinking that once the summer sea ice is gone, it is gone forever, is outdated and not widely accepted anymore.” If that’s “common knowledge” you should have half a dozen links handy.

    I agree with SA that your posts generally belong in a deep hole.

  4. 254
    Dan H. says:

    Do you any scientific data to support otherwise?

  5. 255
    flxible says:

    Dan, that’s about as lame a response as you’ve ever made – you made the unsupported statement, support it, modify it, or disavow it.

  6. 256
    Jim Larsen says:

    253 flxible,

    I don’t see the controversy you see in Dan H’s claim.

    It is common knowledge that sea ice can recover if conditions change back to the previous regime, even after September sea ice is completely gone.

    It is also common knowledge that GIS is a relic which relies on its height to maintain itself. If it melts, then only something akin to an ice age will restore it. I suppose lots of work is being done to quantify how much of a loss Greenland can sustain without entering an unstoppable meltdown. That’s somewhat academic to the more important fact that every decade is a bit warmer and the GIS is a bit lower, so melt is increasing.

  7. 257
    SteveF says:

    Bart, if you are reading this is there some sort of filter you can put in place that automatically blocks any comment containing the terms “warmist” and “CAGW”?

    I’m generally in favour of this experiment but there are too many comments getting through from common or garden loons of the Curry commenter ilk.

  8. 258
    Radge Havers says:

    Ugh. Dan H. weaseled, “if conditions merit.”
    Time Cube!  (if conditions merit)

    Anyway, re debate…What has been clarified? Who has been engaged?

    Science writing: how do you make complex issues accessible and readable?

    The Secret, Subtle Power of Graphic Design

  9. 259
    dhogaza says:

    “I don’t see the controversy you see in Dan H’s claim.

    It is common knowledge that sea ice can recover if conditions change back to the previous regime, even after September sea ice is completely gone.”

    The controversy is that Dan H tried to back up his claim about SEA ice by pointing to a paper discussing the Greenland Ice Sheet.

    Thus flxible’s comment at 253. It’s classic Dan H, refer to a paper that is either unrelated to his claim or contradicts it. Repeated dozens of times.

  10. 260
    Hank Roberts says:

    > can recover [Step One]
    > if [a miracle happens and] [Step Two]
    > conditions change back [Step Three]

    In the cited paper, they model changing instantaneously from high CO2 to 1x CO2.

    How could that happen?

    Be more explicit there in Step Two

  11. 261
    Jim Larsen says:

    259 dhogaza said Dan H made a claim about sea ice and linked to a Greenland paper.

    Seems like an unmentionably small issue. Dan H mentioned both sea ice and Greenland and misinterpreted which half the “demand for a cite for glaringly obvious common knowledge” was for.

    Doesn’t change the fact that Dan H was 100% correct and the request for cite was unwarranted, and a tad puzzling, as I have little doubt that flxible already knew that:

    “The Arctic sea ice, for instance, has timescales of around 5 years to a decade, and so a collapse of summer ice cover could conceivably be reversed in a ‘cooling world’ after only a decade or so (interactions with the Arctic ocean stratification may make that take a little longer though). ”

    In any case, I’m sure that most regulars knew that Dan H was correct, yet none stood up for the truth. Which brings us back on topic. If the regulars here are more concerned with personality than truth, then productive dialogue is going to be very hard indeed.

  12. 262
    Hank Roberts says:

    Jim, you’ve fallen for “let’s all talk about Dan H.” ploy. An optimistic claim, a citation that doesn’t support it, then blah, blah, blah, blah, Dan H., blah, blah, blah.


  13. 263
    Toby Thaler says:

    Now I’m confused, but at least I think I see where I went off the logical track.

    Judith Curry:
    “A number of recent studies find that in models, the loss of summer sea ice cover is highly reversible.” CD article

    Dan H:
    “Unlike Greenland, which is a remnant left over from the last ice age, both sea ice and mountain glacier losses are reversible.” #244

    Jim Larson:
    “It is common knowledge that sea ice can recover if conditions change back to the previous regime, even after September sea ice is completely gone… If GIS melts, then only something akin to an ice age will restore it.” #259

    In my response to Dan H I was addressing the GIS issue. Now I see all speakers appear to be in agreement on that statement (that once gone, it will take another ice age to reconstitute GIS), and the papers I found are redundant of that understanding.

    The question here concerns Arctic sea ice. If there is any dispute it is not about recovery “under a previous regime” (that everyone agrees is likely) but whether or not recovery is even possible under actual current and likely future conditions. I.e., with 400 ppm CO2e and climbing. Curry’s statement is ambiguous, and Dan H also was less than clear. Hence my confusion.

    So, my question is: Does Curry accept that CO2e is not dropping anytime soon, and thus that the “previous regime” is not likely to return soon (centuries if not millenia)? As I noted before, it is clear Curry has accepted at least a major part of the A in AGW, so how could the “previous regime” possibly occur anytime soon?

    My conclusion: Curry’s statement about reversibility is either irrelevant (about an unlikely return to the “previous regime”) or it’s denier nonsense (“previous regime” can return soon because CO2e is not the cause of current ice losses). At the least this somewhat useless dialogue confirms to me that Curry is not very good at making her positions clear. At least not to me.

  14. 264
    Dan H. says:

    Thank you for your show of integrity. I know that I am not the most popular poster here, and as result, my claims seem to require a higher burden of proff than others. Consequently, many of my post get bore0holed, or worse. Your last post was quite refreshing.

    Your last post may have cleared up the issue. Under a warming scenario, the summer sea ice would not return. Should conditions change and cooling occurs, then the sea oce would regenerate, as outlined in Jim’s previous post. With regards to the “previous regime,” what the future holds is largely up to us, and it could occur on a timescale longer or shorter than you entailed. (Funny that captcha should say “years”.”

  15. 265
    Hank Roberts says:

    > as a result … require a higher burden of [proof]

    “Dan H.” mis-states cause and result.

    That account’s “popularity” grows from the record: posting claims “… twisted from the actual facts. Just enough as to allow for some reasonable claim of misreading, but misleading enough to actual give the casual reader a completely wrong impression.”


    AGU’s week preoccupies the attention of the real scientists. Climate blogs fill up with comments spun to mislead casual readers during the annual AGU week. There’s lots of real science news.

    Take a break. Read some science.

  16. 266
    sidd says:

    To return to climate dialogues: I have found that many of the staunchest deniers will agree about mitigation measures such as 1)decreasing CH4 N20, black carbon emission 2)reforestation 3)decrease fertilizer runoff 4)xericulture to name a few. Working with them on projects addressing these issues is more helpful than screaming matches about fossil carbon. I work with some who regarded the notion of AGW as a communist ploy, yet after a few seasons of working with them on reforestation/conservation projects, are more amenable to my arguments. Planning a campaign for a few hundred trees, selecting species and sites with an eye to USDA hardiness zone changes, selecting conservation strips, stabilizing streambanks and hillsides, sweating together in fair and foul weather, manhandling tons of dirt and vegetation, have convinced many more people than lectures on details of climate sensitivity to CO2. And if you must lecture at all, a quiet one on one conversation over a cold beer at the local pub, AFTER you have demonstrated that you don’t mind getting down and dirty will do more to win hearts and minds. Men go mad in groups but come to their senses one at a time.

    Complaints that these are small works, that we require huge, immediate and draconian measures are all very well, but the fact remains that in order to enact draconian measures you must convince a majority of the necessity for action; i submit that small works that include the opposition will convince them much quicker than screams of doom. This may be too slow for some.

    Lastly:it is not the case that unpopular posters bear a heavier burden of proof, or are more often boreholed. The reason for the unpopularity is the same as the reason for the latter two. Posters who have a history of lies (in omission and commission), will be unpopular, will not be believed and will have their comments discarded. Oddly enuf, this happens in real life as well.


  17. 267
    Dan H. says:

    Those with a history of lies, should be treated as such. I am referring to comments which oppose the views of other posters here. There is a difference. I suggest you read some of the threads to see what comments are allowed, and by whom.

  18. 268
    SecularAnimist says:

    Dan H. wrote: “Those with a history of lies, should be treated as such.”

    Note to moderators:

    Given Dan H’s history of lies, please treat him as such, per his request.

  19. 269
    sidd says:

    I must mention a project that has given me a great deal more traction than most others. Over the last few years I have been helping in the installation of solar hot water projects. This is really a no-brainer, yielding immediate savings in both money and fossil carbon output. When you show up and help cut someone’s energy bill, you instantly gain credibility, and are much more likely to be listened to when you suggest other possible changes.

    I think that helping your neighbours in their lives does much more than publishing long screeds on blogs, so I’ll stop here. I have holes to dig, and plumbing to install.


  20. 270

    #269–Sidd, thanks for some very sane and helpful comments.

    On the solar hot water–got any good DIY-oriented links? It’s something I want to put in, and the more sweat equity the better.

  21. 271
    flxible says:

    “I suggest you read some of the threads to see what comments are allowed, and by whom.”

    Like maybe this thread, where Dan H represents about 15% of what’s not allowed by the “whom” that matter here. ;)

  22. 272
    Jim Larsen says:

    262 Hank said, “Jim, you’ve fallen for “let’s all talk about Dan H.” ploy. An optimistic claim, a citation that doesn’t support it, then”

    So point me to the optimistic claim. I only saw a blatantly obvious piece of common knowledge, and since then nary a peep showing anything but total support for the initial contention.

    In a dysfunctional social pattern, when one participant deviates from the norm, the other will often misinterpret the first’s actions and intents to conform to the pattern. People will use any error to force the interaction back into the “proper” mold. Misinterpreting which half of a statement to defend is no-big-deal, yet we’re back into same-old same-old.

    263 Toby T, reverting to [hopefully approximate] the previous regime means geoengineering. So yeah, in this context it’s just fantasy speculation. But that’s just our opinion. To a very low climate sensitivity guy, things could cycle on down naturally.

  23. 273
    sidd says:

    Re: solar hot water
    I shall post a comment on the unforced variations thread as time allows


  24. 274
    Hank Roberts says:

    For Jim Larsen: the 2mm/year claim (at the link given) is one such.

  25. 275
  26. 276
    Hank Roberts says:

    Rebunking is boring.
    Climatedialogue needs better skeptics.

  27. 277
    Jim Larsen says:

    274 Hank R,

    Yes, the standard Dan H posting policies are well known. I’m just saying that in this particular instance they don’t apply. If you want your opponent to learn and grow*, then good results for good behaviour is warranted.

    Ahh, I can see the pseudo-apology… “We’re sorry we treated you like you even though you weren’t acting like yourself.”

    * And if you just want to bash your opponent, then you (and I) have some Jesus or Ghandi stuff to incorporate.

    276 Hank R said, “Climatedialogue needs better skeptics”

    LOL. We all do. It’s tough to meet standards when the group is limited to folks who believe we’re full of ****. But that’s the underlying current. Our opponents TRULY BELIEVE just like we truly believe. Their motivations are generally pure. Absolutely no evil involved. Until we realize that, climate dialogue will just be a big fight with Nature finally ending the squabble, probably via an ice-free arctic ocean and a serious El Nino…

    Can you say 2017? (Just a guess..)

    Captcha says: vanquished psoeexp

  28. 278
    Hank Roberts says:

    “… the fear of crossing a dangerous threshold can turn climate negotiations into a coordination game, making collective action to avoid a dangerous threshold virtually assured…., but uncertainty about the location of the threshold turns the game back into a prisoners’ dilemma, causing cooperation to collapse….”

    Q: What — precisely — is provably dangerous CO2/warming?
    A: Delay is the deadliest form of denial.

    The delay game is a longtime favorite. There are many, many examples. Here’s one current
    How delay works.

  29. 279
    LESacks says:

    From what I can see, this is a very one sided view of the popular debate, i.e. challenging mainline climate science. And that’s been done to death in many fora.
    I’d like to see a balanced debate, with dispassionate moderation, like this to discuss other key issues such which often come up in the online world as:
    – what evidence do we have that the UN is striving towards One World Government?
    – What evidence is there of a wide ranging conspiracy between climate scientists to distort the facts to keep jobs / get grants / support the UN in striving for world domination, given the above is provable.
    – Why, given the number of inquiries and time which has passed, do people insist that the ‘climategate’ email prove anything evil is going on?
    – What makes people think that defamation, threats, and hounding in the courts is an appropriate means of debating science?

    I’m sure Judith et al would be happy to contribute.
    I would be happy to contribute other key questions based on discussion I’ve seen.

  30. 280
    Ray Ladbury says:

    LESacks, Pity the poor denialists. As their position lacks any evidence, and indeed is opposed by mountains of evidence, all they can hope to do is discredit the source of that evidence. Some have made the mistake of thinking that scientists are the source, and so they resort to ad hominem attacks. Others have rightly identified their enemy and have aimed their attacks at reality. You laugh, but Conservipedia carried an entry on “reality” for months that claimed reality had a liberal bias. These intrepid souls can often be found using state-of-the-art computers and high-speed Internet to proclaim loudly that science doesn’t work. Alas, being irony impaired, they find no humor in their actions.

  31. 281
    Jim Larsen says:

    278 Hank asked, “What — precisely — is provably dangerous CO2/warming?”

    I’d say it’s the amount of warming where about half of the population seriously considers geoengineering. (Since we all agree that geoengineering is dangerous, right?) We’re at 0.8C and the oceans aren’t in equilibrium (for sea ice it will get worse as the oceans warm even if we halt the surface temp rise), but the sea ice is dying, so 1C ought to be plenty.

    That 2C limit isn’t about roses and softness and purity at 1.9C, but fuglier and fuglier as you approach 2C.

  32. 282
    Hank Roberts says:

    > what — precisely

    That’s the delay-and-denial question.
    You missed the point of the study I linked to.
    An answer, a precise answer, is — arguable.
    And that works how?

    “… uncertainty about the location of the threshold turns the game back into a prisoners’ dilemma, causing cooperation to collapse….”

    I’m saying, don’t fall for the trick of trying to answer that question. Falling for that question and answering it honestly, instead of realizing that it’s the wrong question, puts off dealing with the problem; delay is denial.