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Comments 1 to 50:

  1. IPCC special report to scrutinise ‘feasibility’ of 1.5C climate goal

    Digby Scorgie @6: To the best of my knowledge, the authors of the IPCC's Summaries for Policymakers are a  combination of scientists and non-scientists from throughout the world. They do not all speak English so translations are required throughout the drafting process. The fact that the reports read as well as they do is a tribute to all involved. 

  2. New study undercuts favorite climate myth ‘more CO2 is good for plants’

    Red Baron @38, you are correct.  Thanks for picking up my slip.

  3. IPCC special report to scrutinise ‘feasibility’ of 1.5C climate goal

    Red Baron @5

    Thanks for your information. I have had a read of your more detailed summary on carbon capture in the soil, and the way to promote this, and what you say is quite compelling with a long list of research links.

    However I don’t have any real specialist soil knowledge. The only soil science I have ever done is stage 1 (introductory) physical geography at university, long time ago but interesting paper that had a component on soils.

    I would agree carbon capture is probably more acceptable to both conservatives and liberals than taxes or kicking the oil companies too directly.

    I agree oil subsidies are absurd, given oil companies are profitable and established without the need for any additional help. Ideally subsidies should be switched to more useful things like carbon capture.

    However this would still be a hard sell politically. It’s a case of favours to campaign supporters, something both democrats and conservatives are tied into. In other words it’s part of the American system where elections are funded by private sector donations. The democrats have tried to put a cap on this, or some limits, but it has been struck down by the courts as unconstitutional to limit donations, so its hard to see what the answer is. Of course some presidents are self funding like Trump, but that guy brings a whole lot of other problems. It's unlikely we would see a self funding president that’s universally admired, but hope springs eternal.

    Back to soil capture. All quite promising practically and could possibly be sold politically despite my reservations, so good luck to you. However the problem is also time related. It would take a long time to make such a proposal have a tangible effect. However I'm being a "contrarian" on the issue here! If such systems also have other benefits as you claim, then that alone makes it worthwhile.

  4. IPCC special report to scrutinise ‘feasibility’ of 1.5C climate goal

    Having studied the last SPM, I conclude that the IPCC didn't use any technical writers to create it, or if they did, the writers were not very skilful.  (In case you're puzzled: BrE "skilful", AmE "skillful")

    As a retired technical writer, I know that a small team of skilled technical writers would've created an SPM that was easily understood by politicians of all kinds, including those with little knowledge of science.  Not only that, but such an SPM would have had a far greater impact.

    This is not to denigrate the efforts of those who did write the SPM.  It's just that very few scientists are good at writing for lay readers.  Nor should one expect anything different, for this is the province of the technical writer, not the scientist.  The job of the technical writer is to "translate" the science into language the lay reader can understand.

    (My technical writing, incidentally, entailed "translating" engineering-speak into technician-speak!)

  5. New study undercuts favorite climate myth ‘more CO2 is good for plants’


     You said, "any negative slope a deceleration, and a zero slope represents constant temperatures."

    I believe you should have said, "any negative slope a deceleration, and a zero slope represents a constant rate of change."

    Since in this case that constant rate of change is above zero, this repesents warming.

  6. IPCC special report to scrutinise ‘feasibility’ of 1.5C climate goal

    @4 nigelj,

     Yes there is an upper limit to the amount of carbon stored this way. Fortunately that upper limit far exceeds all the Carbon in the atmosphere. So it is plenty large enough to lower CO2 and meet the IPCC panel's stated goals.

    Yes such a system requires changes in farming methods, and the agricultural infrastructure that supports farmers. Those do have some short term costs. Fortunately the short term profit increases largely offset those short term costs, and the long term profit potential to both the farmers and the larger economies, both national and international, far exceed any temporary short term costs, and that's even without trying to measure the economic costs associated with ecosystem services losses. Include those and the cost benefit analysis shows a positive outcome immediately.

    Yes there are extremely powerful lobbies resisting the change, and not just agricultural lobbies, but also financial lobbies because of the huge vested interest in the status quo at the commodity markets, banking, insurance, and international trade level. So yes there is a question of political viability.

    I believe I know of a way to break that deadlock. Unlike my previous statement about there being unequivocally the technological ability to do what is needed, this objection I am far more cautious about. I have made a rather detailed practical summary of how I believe that deadlock can be cracked. here But actually breaking the deadlock is another matter.

    I believe that plan would need to be brought before a high level think tank to flesh out and be peer reviewed before it would be acceptable to the IPCC. Since I posted it, I myself already found a few things I would word slightly differently in order to meet the IPCC request for communicating well to policymakers and the public. But you are more than welcome to add your ideas.

  7. New study undercuts favorite climate myth ‘more CO2 is good for plants’

    Red Baron @34, Tamino shows the following graph of 15 year trends of the GISS LOTI:

    The dashed lines are the 95% error limits.

    Because this is a graph of trends in the data rather than the data itself, any positive slope in the graph is an acceleration in the data itself, any negative slope a deceleration, and a zero slope represents constant temperatures.  Very clearly there has been accelerations, eg, from 1900 to 1930, or from 1950-1970, but for the period from 1975-2015 , while there has been some variation above and below the line, the slope has been a close approximation of zero.  Ergo, no acceleration, and certainly no acceleration within error.

    My claim of no acceleration was limited to the period post 1975, so I consider this conclusive evidence.

  8. New study undercuts favorite climate myth ‘more CO2 is good for plants’

    michael sweet @35, consider the OLS trend of the temperature data from 1975 to 2013.  if you take the residual of the temperure data relative to that trendline 1998 to 2013, it has a negative slope over that period.  That negative slope is not an artifact of measurement error.  It is genuinely a feature of the data, and genuinely shows the variation, not the underlying trend, in temperature over that period.  It follows that the measured trend over the 1998-2013 period, ie, the 1975-2013 trend plus the trend in the residual from 1998-2013 is less than the 1975-2013 trend.  In short, there was a slowdown in the measured trend.

    Is the period 1998-2013 cherry picked?  Yes!  Is the slowdown (not hiatus) in the measured trend from 1998-2013 an artifact of short term variation rather than an alteration in the underlying trend?  Yes!  Eoes 1975-2013 trend better show the underlying trend, and therefore is likely to have a smaller residual as projected into the future?  Yes!  

    All of this was known, or should have been known in 2013 to anyone who payed attention to either the statistics or the actual changes in ENSO over the period.  But simply saying that there was no change in the trend without distinguishing between the underlying and the measured trend looks like a denial of the flatening of the graph in that period that is easilly visible to the eye.  I thought I could clarrify that by introducing more specific terminology, but I am beginning to despair of that possibility.

    Just once more.  If you take the OLS trend from 1975-Aug 2016 in GISS LOTI the result is 0.181 +/- 0.035 C/decade.  That is the measured trend over that interval*.  We do not know precisely the underlying trend in that interval, but with close to 0.95% probability it will lie within the error margins of the central estimate.  If we take the OLS trend from 1998-2013 (inclusive) on the same data we get a measured trend of 0.098 +/- 0.128 C/decade.  Again the underlying trend will lie within the error margins with close to 0.95% probability.  Further, the measured trend of the second interval (even though cherry picked).  That is just a matter of mathematical fact.  But the underlying trend in the second interval is very likely to have been included in the error margins of the first interval as well, ie, to be within the 0.146-0.216 C/decade range.  Sometimes in asserting that last fact, defenders of climate science give the appearance of denying that there is a difference in the measured trends of the intervals, but the difference in measured trends is just a matter of mathematical fact.  On the other hand, some scientists, in acknowledging the difference in measured trend, and that it has been longer than similar differences in measured trends in other short intervals within the interval 1975-2016 appear to be denying that there has been no change in the underlying trend.  It is my belief that that is a matter of appearance only, following only from a failure to distinguish clearly between the underlying and measured trends.

    (*Note, the measured trend is the central estimate, but has much smaller error margins, being a function of measurement error only.) 

  9. IPCC special report to scrutinise ‘feasibility’ of 1.5C climate goal

    Red Baron @2 

    Sequestration of carbon in soils does have some appeal to me, but you are up against two big challenges. Firstly there would be an upper limit on how much carbon can be stored this way.

    Secondly such a system requires a lot of changes in farming methods that have some short term costs in some cases. Farming lobbies are notoriously powerful, ask the EU or the United States. So how politically viable is it? 

    So even assuming some uptake of the idea, carbon capture looks like a partial answer to me.

  10. IPCC special report to scrutinise ‘feasibility’ of 1.5C climate goal

    The charts in the article do indeed show some significant differences in impacts between limits set at 1.5 degrees versus 2 degrees. In fact the impacts are pretty sobering even at 1.5 degrees. However presumably you would say 1.2 degrees would be better still.

    The point is limiting emissions to 1.5 degrees is a monumental task. Even limiting emissions to 2 degrees is a huge challenge, so is there much point considering lower goals? You are in danger of generating a mindset in the public where they respond that the whole thing is practically impossible, so we might as well give up on any goal.

    There has to be a viable path forwards, even if it does require some significant sacrifices, but they have to be sacrifices that preserve a reasonable basic quality of life or people will say the solutions to global warming are worse than the problem. Their perception may or may not be correct, but our political systems are democratic, and this means we have to convince the public.

    2 degrees seems a more achievable target. Yesterday I read an article in a current affairs magazine, reporting on Antarctic ice loss. Apparently Rob DeConto has written a report in 'Nature' with some evidence that 2 degrees is fundamental in terms of Antarctic ice. The report basically suggests Antarctic ice would remain reasonably stable if temperatures are limited to 2 degrees, (I take that to mean a very slow rate of ice loss) but once you get above 2 degrees there is a fairly sudden acceleration and much more ice loss. This appears to suggest 2 degrees is the number we should worry most about.

  11. IPCC special report to scrutinise ‘feasibility’ of 1.5C climate goal

    Well I have stated multiple times this statement is flat out unequivocally wrong.

    “We will need negative emissions on a large-scale and for a long period of time to bring global temperatures back down to 1.5C. This isn’t possible with current technologies.”

    Biological carbon capture and storage is possible with current technologies. Will we have the strength of character to use it? Doubtful. But it most certainly is possible.

    To be policy-relevant, the report will need to spell out what’s to be gained by limiting warming to 1.5C, as well as the practical steps needed to get there within sustainability and poverty eradication goals.

    That too! BCCS is also helpful in both those goals as well. In fact moving beyond a meager "sustainable" to actually regenerative, and moving beyond a meager "low cost" to actually profitable. And moving beyond a meager "profitable to overall economies" to specifically the most profit increases to the lowest earners living below the poverty line.

  12. IPCC special report to scrutinise ‘feasibility’ of 1.5C climate goal

    Does the IPPC have a position on where we stand now in terms of degrees of warming?

    (This SkS post is pretty sobering if 1.5C is the goal.)

  13. New study undercuts favorite climate myth ‘more CO2 is good for plants’


    Perhaps I misunderstand you.  When I put my straight edge on the Lowess curve I get the same result you did: there is no trace of a leveling off or decrease of increase in the temeperature record after 1975.  There is a hint of increase at the very end due to the extreme values we see currently.  There is no trace of a "hiatus".

    Calculating slopes to 1998 while suggesting that current extreme values are due to El Nino is cherry picking.  You are taking a noisy record and claiming it is a trend.  If that is the remaining argument I stand on my claim that El Nino is responsible for the entirety of the claimed "hiatus".  

    There was no "hiatus".  There are people who falsely argue that the high record in 1998 generated interesting data.  2016 shows that is incorrect.

  14. New study undercuts favorite climate myth ‘more CO2 is good for plants’


    hmmm I honestly don't see it. To me all those graphs, to one degree or another seem to transition from an accelerating rate of temperature increase to a steady (or more steady) rate of increase. So I don't understand why you said,

    "Contrary to Red Baron, I would not have characterized the temperature series from 1975-1998 as accelerating."

    Maybe it just depends what endpoints you choose? I have seen that exact same data graphed by rate instead of temps so as to make it appear horizontal flat and incorrectly used by climate deniers to "prove" the hiatus means no warming happened during the hiatus, when actually a closer inspection shows increases in temp. When you plot rates instead of temps the graph appears completely different and fools a lot of people.

    Anyway I bow to your expertise.

  15. 2016 SkS Weekly Digest #39

    This time of year (late Sept) usually means the CO2 levels have hit a seasonal bottom at Mauna Loa. This year it bottomed comfortably above 400ppm. Last month of observations show that every day the average were within 400-402 while only some hourly averages notched below. So, almanac collectors, get an ampule of air from Aug 29 (which by a statistical fluke ended with 399.5ppm) if they still have it! Otherwise you won't get it: other stations that might still hit 400ppm extremum next year, (eg. Cape Grim inTas) may not be selling them, Antarctic stations definitely do not.

    I still remember from primary school that CO2 should constitute 0.035% of the atmosphere. It was still 0.039% when I first started to learn climate science. Even that is an ancient history already.

  16. 2016 SkS Weekly Digest #39

    Thanks Bob. Gavin on RC just expertly clarified what is also my concerns about this study. Nothing to add.

  17. 2016 SkS Weekly Digest #39


    There is a post on this paper over at RealClimate:

  18. 2016 SkS Weekly Digest #39

    This new paleo study in Neture:

    Evolution of global temperature over the past two million years

    creates some spin in the media. Particularly the sentence in the abstract:

    This result suggests that stabilization at today’s greenhouse gas levels may already commit Earth to an eventual total warming of 5 degrees Celsius (range 3 to 7 degrees Celsius, 95 per cent credible interval) over the next few millennia

    results in claims (e.g. in smh here wrong IMO) that we may be already committed to 7 degree warming.

    I don't have access to the full text to form my opinion about that claim. Anyone who has, or who has found a better op-ed can explains how this new study relates to, and how it changes the constrains on ESS estimates? Thanks.

  19. New study undercuts favorite climate myth ‘more CO2 is good for plants’

    Red Baron @31, when I lay a straight edge against the Lowess smooth in the figure at 30, it is essentially a straight line from c1974 to c2010, after which it diverges slightly upward (accelerates).  The divergence of the high values in 2016, and is probably an artifact of the fact that Lowess smooths given greater weight to final values than to intermediate values in determining the end point.  To see that, compare the endpoints of this comparison of the spline, Lowess, and modified Lowess (ie, the smooth used by Tamino) by Tamino:

  20. New study undercuts favorite climate myth ‘more CO2 is good for plants’

    michael sweet @, I repeat:

    "I think you need to carefully distinguish between the rate of change of the instrumental record (ie, the trend with error based only on the error in determination of the anomaly values) and the climatological trend (ie, the trend with the error based on the actual fluctuations in the temperature record, as with the SkS trend calculator)."

    My comment about there clearly being a reduction in trend refers to the trend, "with error based only on the error in determination of the anomaly values".  With respect to the climatological trend, that Tamino discusses I state:

    "[G]iven that for all periods longer than 5 years, the trend error includes the trend from 1975-1998 within its values, there has been no statistically significant reduction in trend, and hence no compelling evidence of any such reduction."

    That is clearly in agreement with Tamino.

    I am inclined to think your misunderstanding is due to the poor way in which I expressed myself.  So to start with, in determining the trend in GMST, there are two sorts of noise - climatological noise, in which the GMST varies from the underlying trend due to short term influences such as ENSO and volcanoes; and measurement noise, in which the observed data varies from the actual GMST due to limits in accuracy of measurement and/or coverage.  Corresponding to these two sorts of error are two sorts of trend, the "underlying trend" corresponding to the former, and the "measured trend" corresponding to the later.  The later form or erro generates an uncertainty in the trend determination approximately equal to 2*measurement error/decades in Degrees C/decade, or about 0.06 C/decade for the period 1998-2016.  

    As it happens, GISS LOTI trend from 1998-2016 is 0.026 C/decade less than the 1975-1998 trend, so that if that was all the data we had, we could not determine that the change in measured trend represented an actual change or simply an artifact of measurement error.  As it happens, however, the difference between the 1998-2013 trend and the 1975-1998 trend is 0.065 C/decade.  That tells us the change in trend between the two is a real change in the measured trend, ie, not just an artifact of measurement error.  It tells us nothing about whether or not there is a change in the underlying trend.

    IMO, a lot of the confusion on this topic comes from talking at cross purposes.  Defenders of AGW discuss the underlying trend in which there has been no determinable slowdown, while "Skeptics" discuss the measured trend, in which there has undeniably been a slowdown, but then often confuse that claim with a claim that the underlying trend has slowed down (or even fallen to zero).  I think this confusion has also made its way into the scientific literature, with Fyfe et al accepting the reality of a slowdown in the measured trend and then discussing the reasons for that slowdown in the measured trend; and others insisting there has been no slowdown in the underlying trend (and giving reasons).

  21. The Madhouse Effect of climate denial

    Sounds like an excellent book. Clearly we are altering the climate at considerable cost to future generations, so this begs the question of why the climate change denialism?

    I can think of 100 reasons for climate change denialism, but I think it boils down to people being worried about costs of moving away from fossil fuels, and being rather selfish about this in ignoring future generations. If the climate problem could be fixed for free I doubt there would be many denialists left.

    Some people also dislike taxes on ideological grounds and conservative parties seem particularly sceptical about climate science. This ideology is put above almost every other concern it seems.

    The denialists rationalise their position by claiming the science is wrong or global warming could prevent an ice age (which it cant). Or that C02 is plant food, which is a massive over simplification of the issues.

    However some countries have substantial renewable energy already, and it hasnt bankrupted them, and electric cars are becoming more affordable, and are very cheap to run. The costs of the transition are being exaggerated by the denialists.

  22. New study undercuts favorite climate myth ‘more CO2 is good for plants’

    @Tom #29,

    You said, "Contrary to Red Baron, I would not have characterized the temperature series from 1975-1998 as accelerating. Considering measurement errors only, it has been characterized by periods of lesser and greater trends of various length. None of those periods have been sufficiently long to be statistically significant when error from short term temperature variations have been included."

     I don't know Tom, that graph just posted by Michael #30 sure appears to be an acceleration of increasing temps (curved) that leveled off to a steady increase of temps (straight line). I guess it just depends how long a time frame we need to declare it significant?

    Either way the important thing in my opinon is that no thinking person can deny that temps are increasing, The finer points of accelerating increases or steady increases and at what time periods those increases are significant are important for prediction future climate, but not really needed to show AGW exists. And most pertinent to this thread; While the CO2 fertilization stabilizing feedback is real, it isn't large enough to halt AGW.

  23. CO2 was higher in the past

    Until the Faint Young Sun Paradox is resolved we cannot claim that the geological record agrees with holocene climate models.

    Moderator Response:

    [PS] You need to tell us more about what you mean. The faint young sun paradox concerns solar output billions of years ago and irrelevant to the holocene. Greenhouse gases give us a good resolution to the paradox from what can be construed about past atmosphere so what is that you think is unresolved of relevance here?

  24. 2016 SkS Weekly Digest #39

    here we have an erroneous link:
    [...]Something went wrong at WUWT. Is Anthony Watts ceding his title? by Sou (HotWhopper)[...]

    here is the correct url:


    Moderator Response:

    [JH] Thank you for bringing this glitch to our attention. The correct url has been inserted.

  25. New study undercuts favorite climate myth ‘more CO2 is good for plants’

    Tom at 29,

    You state that "clearly there has been a reduction in trend in the 21st century".  Tamino's recent post on August temperature showed this graph:

    recent temperature graph

    I do not see any decrease in the temperature increase through the 21st century.  I see a very slight decrease if you start at 1998, an obvious outlier that is not included in the 21st century.  I think the discussion of a "hiatus" has devolved into a cherry picked argument of a change from 1998-2013.  Since that itme period is too short for statistical significance, and starts with a strong El Nino and ends with a strong La Nina, for me there is no "there" there.  El Nino patterns explain any change.


    There is a great deal of dispute about the "hiatus".  Song et al are incorrect when they presume that a hiatus occured.  Tamino and others, some cited by Song and others not, have shown no significant hiatus occured.  There is some continuing discussion of the temporary factors that caused the temperature to temporarily increase slower, now countered by rapid increase back to the mean over the past three years.  Song is a late addition to this discussion.

  26. How climate science deniers can accept so many 'impossible things' all at once

    Glen Tamblyn @16

    Very true. For centuries people believed certain thngs were fixed and absolute, particularly moral beliefs. Science has shown nothing is fixed except the laws of physics and speed of light. It sure pulls the rug out, and leaves us making decisions on the basis of what seems best for most.

  27. How climate science deniers can accept so many 'impossible things' all at once

    Why do some people deny climate science? There are clearly several possibilities including religion, but I do think the main one is as follows:

    Some people are driven by strong personal greed, worries about costs being imposed on them, so they deny the science and gravitate to small government / conservative leaning parties. (Which creates a strong political dimension to the whole issue that can't be avoided. Polls show a preponderance of climate denialism in conservative leaning parties)

    Proof: If climate change could be fixed at no cost, there would be almost no denialists. 

  28. How climate science deniers can accept so many 'impossible things' all at once

    There are other dimensions to denial, falling under the umbrella term 'implicatory denial'. The one that gets most attention is rejection of the responses to AGW - regulation, government roles, shutdown of the FF industries that have obvious consequenses that can disturb people.Call this world-view implications of the responses

    But there is another dimension that gets less attention. The impact for various peoples world-views that AGW is possible at all. This is often seen in ideas like 'It is arrogant to think that humanity can impact something as big as the climate', or 'God wouldn't make a world where that is possible' etc. etc...

    It is easy to think that this second type of denial is actually a cover, a rationalisation for the first type. When quite possibly this second dimension may actually be the stronger world-view driver for denial. How does the old saying go, 'Man does not live by bread alone'? Surely there could be many people who have deep-seated world-views, such as religious ones, that are profoundly challenged by the implications of AGW even being possible.

    This is just the latest in a long history of discoveries in science that deeply challenge traditional, millenia old, perhaps even genetically based world-views.

    • Stars aren't on celestial spheres with the earth at the centre
    • No evidence of the existance of Gods.
    • We don't need Creation to explain us, our minds and origins, just physics.
    • We aren't the centre of the universe, just a few oversized Australopithicenesliving on an insignificant speck of dust.
    • We are descended from other species, ultimately from bacteria.
    • The position of s few stars in the sky can't influence your life (except when you influence yourself by believing that they can)
    • etc. etc.

    We often don't grasp just how science has disconnected us from our historical roots. In not much more than 1 century, 2 at most, we have become aliens on our own planet compared to all the 1000's of generations of our ancestors before then. A Neanderthal, a early Australian Aborigine, the builders of the Great Wall of China, an ancient Sumerian, a jew from the time of Christ, a Mayan farmer, a medieval blacksmith, an 18th century miller, still much of the world today. All of them would utterly understand each other and their shared sense of the world vastly more than they could ever understand Homo Scientensis.

    Not surprising really that some people don't react very well or rationally. Science keeps pulling the entire carpet of meaning out from under them.

  29. How climate science deniers can accept so many 'impossible things' all at once

    I think the article makes a very good point. If the root of denial is a strong distaste for any measure that might mitigate climate change, then it doesnt matter to the denier really what the argument is, so long as it prevents any action. Many deniers are happy to take "its not happening; its not us; its not bad and its too hard to fix" positions simultaneously.

  30. New study undercuts favorite climate myth ‘more CO2 is good for plants’

    martin @27, I think you need to carefully distinguish between the rate of change of the instrumental record (ie, the trend with error based only on the error in determination of the anomaly values) and the climatological trend (ie, the trend with the error based on the actual fluctuations in the temperature record, as with the SkS trend calculator).  With regard to the former, clearly there has been a reduction trend in the 21st century.  With regard to the later, given that for all periods longer than 5 years, the trend error includes the trend from 1975-1998 within its values, there has been no statistically significant reduction in trend, and hence no compelling evidence of any such reduction.

    Contrary to Red Baron, I would not have characterized the temperature series from 1975-1998 as accelerating.  Considering measurement errors only, it has been characterized by periods of lesser and greater trends of various length.  None of those periods have been sufficiently long to be statistically significant when error from short term temperature variations have been included. 

  31. How climate science deniers can accept so many 'impossible things' all at once

    Art Vandelay @10, the issues you raise are discussed in the paper explicitly under section 1.4.  In that section the authors point out that they have documented instances of incoherence in the positions  of several individuals in Table 2, including Plimer (3 examples), Christy (1 example), Watts (2 examples) and Monckton (3 examples).  Their table 2 is certainly not exhaustive in the cases of Plimer, Watts and Monckton, and is from my experience not exhaustive as to individuals demonstrating this sort of incoherence.

    Further, they argue that even if the incoherence were within the group, but not within particular individuals, "...there are several reasons why this would not be reflective of “healthy debate” or “scientific diversity”".  They go on:

    "First, as we noted at the outset, science strives for coherence (e.g., Douglas 2013; Laudan 1984; Roche 2014; Thagard 2012) and there is little room for incoherent theories in science (and any incoherence contains within it an impetus for reconciliation). ...  It follows that if climate denial were to constitute scientific reasoning—as is its purported purpose (e.g., Solomon 2008)—then it would exhibit coherence notwithstanding the presence of multiple agents and actors. The fact that it fails to achieve this and that incoherence is manifest at the aggregate (Table 1) as well as at the individual level (Table 2) leaves little doubt about the non-scientific nature of denial.

    Second, the theoretical coherence of consensual climate science does not prevent robust debate. ... No such corrective processes can be observed in denialist discourse which focuses entirely on its opposition to mainstream science and does not entail any debate among the incoherent positions we have revealed in this article.

    The absence of any corrective resolution process among climate contrarians raises the question to what extent incoherence is perceived or recognized as a problem by people who hold contrarian views. This question is difficult to answer with any degree of certainty, although one can attempt to make an inference by examining the “revealed preferences” (cf. Beshears et al. 2008) of contrarians. In the context of climate change, one way in which preferences might be revealed is by the willingness to incur financial risks to back one’s position in a bet. Bets have a long history as a tool to reveal people’s preferences.


    It is notable that although contrarians readily claim that the Earth will be cooling in the future, most are unwilling to bet on their stated position (Annan 2005). ... The unwillingness to bet is thus indicative of the over-arching rationality of denial, notwithstanding its argumentative incoherence and non-scientific nature."

    Obviously you should read the full text in the original rather than my quote alone, as I have ellided much of the text for brevity.

    For myself, I have often noted within the "skeptical" community a tendency by individuals to comment appreciatively on any claim purported to refute AGW, even when such claims contradict the favoured theory of the individual.  That indicates fairly clearly to me that the purpose of the theories advanced is not to vindicate those theories, but to "refute" AGW.  If in fact the proponents of the diverse theories of AGW denial were primarilly motivated by the science, those who thought warming was caused by the rise in GHG, but that climate sensitivity was low would have as much of a problem with those who thought the warming was primarilly due to the Sun as do proponents of AGW, and similarly with those who thought the recent temperature increase was due to the PDO or AMO.  Instead, there behaviour clearly indicates that they reject AGW, and will give a favourable reception to almost any theory that similarly rejects AGW, even when that theory is as incoherent with, or more inchorent with their own theory than it is with AGW.  (This might be considered an aspect of the authors second point quoted above, but I think it is different.)

    All that said, there are two fuzzy divides within the AGW denial community.  First, there is that between those who reject the possibility of an enhanced greenhouse effect altogether, and those who do not.  This is illustrated by another of Anthony Watts incoherences, for while he rejects the label "denier" as applied to himself as being a deliberate, and odious moral comparison with holocaust deniers (rather than an indication that his doubt is based on pseudoscience), he is happy to call the "dragon slayers", ie, those deniers who reject an enhanced greenhouse effect entirely deniers).  The weaker barrier is between deniers who reject any possibility of AGW being either significant or harmful, and those who merely insist it will be moderate (ie, that the mean Equilibrium Climate Sensitivity lies between 1 and 3 C, and that increased damage with increased GMST is low).  These categories are fuzzy because not all deniers accept that one or either category represents a significant division in the community, and because a number of those in the second category deliberately misrepresent their position by labelling it as belonging to the third category.  It should be noted in passing that not all members of the third category, the "luke warmers" are in fact deniers, ie, those whose rejection of AGW shows the hallmarks of pseudoscience.

  32. How climate science deniers can accept so many 'impossible things' all at once

    We have this particular radio talkback host / radio broadcaster in my country who is an extreme climate change sceptic. He holds all the following contradictory arguments and new ones are added quite regularly: Climate change is a socialist scam, climate change is political correctness (whatever this means), climate change is all due to solar activity, we are probably altering the climate but only slightly, we could be altering the climate quite a bit, but theres nothing we can do about it.

    There are many more but I have forgotten. I'ts just amazing and yet this guy is basically reasonably intelligent, although he does admit he is weak on science.

    The only conclusion I can draw is that this person has determined he simply doesn't believe we are altering the climate on "gut reaction" and trusts his "gut" above all else. 

    He also has deep political suspicions of the green movement, and sees the whole climate issue as an ideological war. And in ideological wars rationality and consistency is the first victim.

  33. How climate science deniers can accept so many 'impossible things' all at once

    Art Vandelay @10

    Fair enough in general. However there is simply no homogenous collective implied and Chriskoz has summed it up. It is just a tendency for some sceptics to engage in conspiratorial thinking like "climate change is a socialist scam" and Trumps absurd claims that climate change all originated with the Chinese as a way to destroy American industry.

    However I agree there are many reasons for climate scepticism including vested business interests, ignorance about science, a contrarian nature, genuine doubts about the science, a desire to be different and get noticed, loving your car, and political ideologies. Its a complex interplay of things, that probably varies from individual to individual.

    We are of course looking for one core underlying reason for climate change scepticism, because thats what humans do. We look for reasons and we try to simplify and usually a chain of actions has some important core driving function, with other factors superimposed.

    Political ideologies may be the core underlying reason for climate scepticism, but Im not 100% sure. I mean conservatism and small government, versus liberalism and an acceptance that economies need to be regulated, especially relating to environmental issues.

    I have read Plimers book "Heaven and Hell". It is indeed contradictory, and also has several graphs that form the core feature of his argument. It's intereting that the graphs have no sources noted, and seem to show temperature trends and other trends quite different from the mainstream material I have seen.

  34. New study undercuts favorite climate myth ‘more CO2 is good for plants’

    @27 Martin,

    I can't answer for Tom. And BTW Tom is the real expert, not me. My field is one of the closely related fields. But I have taken courses on this and how to communicate it effectively to laymen. So I will give it a shot in simplified form. I am sure Tom can add his more expert POV when he gets a chance.

    I see no major difference between Song, Tang and Wang and the majority of climate science research. It is more of a refinement than anything that goes against the consensus.

    Yes global surface temp has a noisy signal because the biosphere is a highly nuanced complex system with many stabilizing and reinforcing interactions between it and the atmosphere, the sun, the moon, the magnetic fields, the core, mantel and crust, etc etc etc. There are hourly cycles, daily cycles, monthly cycles, yearly cycles, decades long cycles, thousand year cycles and on and on. All these cycles interact with each other to make predicting surface temps difficult. But we can over time pull out long term trends from the noise.

    Warming has not slowed down. Surface temp increases have not slowed down either. The acceleration of warming of surface temps paused for a short period of time. Too short a time to be sure if the acceleration will pick back up and cancel out the hiatus or not. But either way warming of surface temps never stopped. Surface temps are increasing as rapidly as they ever did. Song, Tang and Wang does not claim it stopped. You think they claim that because you misunderstood the wording they used.

    Increasing rate of increase stopped temporarily, (acceleration towards an even higher rate of increasing surface temps) but it is too short a time frame to consider this a long term climate trend, or just noise. If it should continue past 30 years at a steady rate of increasing surface temps instead of an accelerating rate of increasing surface temps, then maybe the hiatus might mean a fundamental change in AGW is happening.  Until that happens though, and it hasn't yet, it can probably be better explained as short term variations having no effect on long term climate trends.

    I hope that helped instead of confusing you even more.

  35. New study undercuts favorite climate myth ‘more CO2 is good for plants’

    First, I would like to thank both Tom Curtis and RedBarron for patiently explaining these issues.

    Yes, surface temperature and global warming are not identical and slowdown would be a better term than hiatus.

    Even so, do I correctly understand you both that

    1) You do not agree with Song, Tang and Wang that there has been a slowdown in surface temperature, merely no acceleration?

    2) The global surface termperature is a noisy signal and within the error bands the surface temperature has continued to increase through the nineties of the previous century right up to the present just as it has in the decades before that?

  36. How climate science deniers can accept so many 'impossible things' all at once


    I also think it's a bit dangerous to refer to "deniers" as a homogenous collective.

    Which part of the article talks about climate science deniers as "homogenous collective"? I think your opinion does not apply to this study. To quote the OP, this study only tries to find the reason for climate science denial by claiming that:

    [examples of] “incoherence” only hold together in the minds of the deniers if you apply types of glue known as “conspiracist ideation” and “identity-protective cognition”.

    i.e. this is the study about the cognition machanisms behind the examples of denial and not the classification of the types of denial. Your suggestion about deniers being treated as "homogenous collective" is obviously groundless IMO, therefore there is no "danger" here.

  37. New study undercuts favorite climate myth ‘more CO2 is good for plants’

    @24 martin re: @RedBaron #12

    Your quite right, my quote from the paper’s introduction does indeed refer to a slowdown of global warming.

    No martin, you missed it again. global warming has not slowed down, the rate of increase of surface temps appears to have slowed. That's a very different thing.

    I'll make a very simplified analogy to something you are probably more familiar with so as to better explain the flaw to you. As a thought experiment consider a car accelerating to maximum top speed. When you start the car and begin accelerating, pedal to the metal, you have two factors happening. First your actual speed is increasing, but also your acceleration is increasing. As you accelerate through the gears and go through the mid range speeds your acceleration levels off to a steady acceleration but your speed continues to increase. As you approach top speed your acceloration drops to zero, and your speed becomes steady at top speed. You cant increase speed or acceleration any further due to friction and wind resistance, but you are still traveling very fast. Your speed hasn't slowed at all.

    Now just substitute global warming for speed in the above thought experiment. Instead of wind resistance, substitute CO2 fertilization effect, ocean currents, etc. for your stabilizing feedbacks. Then you should be able to understand that much like a car traveling near top speed is still traveling rapidly once the acceleration drops to zero, so also global warming is still rapidly ocurring during the so called "hiatus". In fact surface temp increases due to global warming have not slowed at all. They just are not accelerating as they were earlier. They probably will start accelerating again as there is a new "top speed" at every higher CO2 level. But during the "hiatus" acceleration dropped to zero. Speed didn't drop to zero, acceleration did. Surface temp warming didn't drop to zero, rate of increase in surface temp dropped to near zero. It is still warming, and still warming at an alarming rate, but for a little while at least that rate hasn't accelerated out of control. It's a good thing too. Because of the haitus in part, we still have time to hit the brakes on AGW.

    I agree with Tom, the term "hiatus" is very misleading. Hopefully that analogy as a thought experiment will help you to no longer be misled.

  38. How climate science deniers can accept so many 'impossible things' all at once

    Nijelj @9 "Where did the article suggest a global conspiracy?"

    Nigel, no it doesn't state that directly but it does appear to imply that Deniers are a collective that present an incoherent message. 

    Obviously, a structured and organised denier 'collective' doesn't exists, but I also think it's a bit dangerous to refer to "deniers" as a homogenous collective. Within the denier camp, to use the popular label. there exists a diversity of opinion, reflective of the large number of individuals and their personal views. 

    Of course I comletely agree that it's valid to single out prominent individuals whose messgae is inconsistent, such as Plimer. 

  39. 375 top scientists warn of 'real, serious, immediate' climate threat

    How many more times do scientists have to warn of a real, serious, immediate climate threat before politicians commit to doing something about it?  Politics in science can be trouble, but adding science to politics might result in useful change.  For many, political arguments are about emotion rather than facts, and the climate change "debate" is used as a tool of manipulation at the expense of the evidence.

    Unfortunately, the facts aren't good enough by themselves.  We need to be wise to the political games that garner far more attention than cold, hard facts.  If we can use political lobbying as a means to educate and to actually do something about the problem, then we should.  The thermometer isn't partisan, but the outside world is.

  40. How climate science deniers can accept so many 'impossible things' all at once

    Art Vandelay @4

    Art says "The first point to question is whether climate denial is really a global conspiracy. Unbless this is provable then the study is itself indulging in conspiratorial thinking"

    Where did the article suggest a global conspiracy? It didn't and only referred to conspiratorial modes of thinking. Your comment is a classic strawman argument. This is interesting as climate change sceptics constantly use strawman arguments. For example "the warmists said the world would be underwater by now, and it isn't so clearly AGW is a hoax". Of course they never said the world would be underwater by now, but seeds of confusion have been sown.

    Climate sceptics have no interest in the truth, only in muddying the waters and spreading doubt. We need honest scepticism that keeps everyone on their toes, not misleading sludge.

  41. How climate science deniers can accept so many 'impossible things' all at once

    Pity most deniers don't have a little more science in their quiver.  It is good to have someone to keep us on our toes.  For the most part, their arguments are too easily shot down.  Mind you, look at how many people believe in a kindly old gentleman sitting on a cloud and knowing our (all 7b of us)every thought.  Talk about cognitive dissonance.  Climate change denial hardly even rates against that level of self dillusion.

  42. How climate science deniers can accept so many 'impossible things' all at once

    Art Vandelay - No conspiracy required for a group with common outlooks to engage in similar arguments, including similar disconnects between contradictory claims due to the result being more important than the reasoning...

  43. How climate science deniers can accept so many 'impossible things' all at once

    One of the "best" examples of the incoherence found in climate science denial - and Graham Readfearn mentions it briefly - is Ian Plimer at odds with himself even within the same book and often just a few pages apart. We have a page at Skeptical Science just for that and it's too good not be shared here. So, check out "Plimer vs. Plimer"!

  44. How climate science deniers can accept so many 'impossible things' all at once

    A revenue-neutral carbon fee,such as the one being proposed by Citizens' Climate Lobby, will allow the free market to decide how to cut emissions without increasing the size of government.

  45. How climate science deniers can accept so many 'impossible things' all at once

    The first point to question is whether climate denial is really a global conspiracy. Unbless this is provable then the study is itself indulging in conspiratorial thinking. 

    Moderator Response:

    [JH] Your comment is on the cusp of being nonsensical sloganeering which is prohibited by the SkS Comments Policy.   

  46. New study undercuts favorite climate myth ‘more CO2 is good for plants’

    martin @6, @11, and @24:

    1)  Song, Wang and Tang (2016), to which you linked @6 above states:

    "The rate at which the global average surface air temperature (Ts) increases has slowed down during the past few decades1. This so-called hiatus, pause, or slowdown of global warming has inspired investigations into its potential causes worldwide1,2. Although some researchers doubted the existence of a global warming hiatus because of coverage bias3,4, artificial inconsistency5, and a change point analysis of instrumental Ts records6, it is now accepted that a recent warming deceleration can be clearly observed1. There are two primary hypotheses to explain the recent slowdown of the upward trend in Ts7. Both hypotheses attempt to explain the contradiction between the trendless Ts variation and the intensifying anthropogenic greenhouse effect resulting from the steadily increasing emission of greenhouse gases (GHGs)."

    a) Taking an analogy from formula 1 racing, if a driver finds themself in the unfortunate position of needing to conserve fuel, commentators will be universal in saying that they have slowed down.  They will not say that the driver has "paused", or "taken a hiatus".  This universality of expression will be because they are competent speakers of the English language, in which a "pause" or "hiatus" requires "a short period in which something such as a sound or an activity is stopped before starting again".  As the period 1998-2013 has not been a period with a stop in the increase in GMST, the terms "pause" and "hiatus" are false descriptors of the phenomenon.  They have come into usage because of deliberate attempts of climate change deniers to deceive, and intruded into the scientific literature as the result of climate scientists not being careful with their language.

    b)  Whether or not there is a reduction in the Global Mean Surface Temperature (GMST) trend from 1998-2013 relative to the trend from 1975-1998 depends on what you count as noise.  The trend estimate is, of course, the best estimate of the linear trajectory of the data on the assumption of no noise.  It is because of the no noise assumption that it makes sense to tell people to pay attention to the trend rather than the variation in projecting future states.  That being the case, whether or not there has been a "slowdown" depends in part on what is counted as noise.  If you are interested in likely change in the mean climatological state, noise includes volcanoes, short term oceanic fluctuations such as ENSO, etc.  If we are only interested in the specific trajectory of GMST, then noise includes measurement error, including error due to incomplete and/or uneven distribution of meteorological stations.  Whether or not you consider there to have been a slowdown may depend crucially on which you are interested in, and that has varied between different studies of the issue.  In general, while there was reason to think there was a reduction in the trend in GMST (considered as such) from 1998 to 2013, there has been no substantive evidence of a reduction in the rate of change of the mean climatological state with regard to GMST over the same period.  In fact, as several studies have shown, quite the contrary.

    c)  Song et al cite Fyfe et al (2016) as proof that there has in fact been a "hiatus" (strictly, slow down) in GMST, and as establishing a consensus on that point.  However, only one author of Fyfe et al (ie, Ed Hawkins) was also an author of one of the papers Song et al cite as being shown to be obsolete by Fyfe et al.  Clearly the authors of those papers may still disagree on that point; and equally clearly Song et al's claim that Fyfe et al's conclusions are now "accepted" is not evidenced merely by citing Fyfe et al.

    d)  Finally, on this point, Song et al's claim that the period between 1998 and 2013 (ie, the period discusses in Trenberth (2015), which they cite) is "trendless" is clearly misleading.  Specifically the NOAA trend from 1975-1998 was 0.160 +/- 0.084 C per decade.  That from 1998-2013 was 0.086 +/- 0.148 C per decade.  While the 1998-2013 trend was clearly within error of a zero trend, it was in fact closer to, and within error of the 1975-1998 trend.  Therefore it is less accurate to call the trend "trendless" than it is to say that it was the same as that in the prior period.  In fact, neither claim should be made from that data if we are considering the trend in GMST alone (ie, considering measurement and coverage errors alone).  In contrast, if we are considering change in mean climatological state, we should note that the period 1975-1998 goes from the strongest La Nina event in the late twentieth century, to possibly the strongest El Nino event on record; and that 1998-2013 goes from that same El Nino to a La Nina (2011/12) that was as strong as that of 1974/75.  Both, therefore are perturbed from the trend in mean climatalogical state with regard to temperature, and in opposite directions.  The clear conclusion is that the trend in mean climatalogical state is unlikely to have been perturbed over that period, and if so - by very little.

    To keep this in convenient post sizes, I will discuss the other, more interesting aspects of Song et al in another comment. 

  47. How climate science deniers can accept so many 'impossible things' all at once

    Red Baron @2

    I think the article is basically right. Small government free market ideologists are often climate change sceptics in my experience. Conservatives and Republicans do tend to be small government and against regulation. Remember Ronald Reagon?

    Of course they can also be hypocrites, and happy to subsidise things or support certain types of regulations when it suits. Your post has only really proven they are hypocrites.

    However I agree about oil subsidies. This is totally unjustified policy, as the oil industry does not need subsidies! And both Democrats and Republicans appear guilty of supporting these. As you say it’s too do with campaign financing and repaying favours and this is all most unfortunate.

  48. How climate science deniers can accept so many 'impossible things' all at once

    Because cutting GHG emissions requires interventions – such as regulation or increased taxation – that interfere with laissez-faire free-market economics, people whose identity and worldview centres around free markets are particularly challenged by the findings from climate science.

    Oh really? Fossil-fuel consumption subsidies worldwide amounted to $493 billion in 2014, with subsidies to oil products representing over half of the total. Those subsidies were over four-times the value of subsidies to renewable energy. That proves 2 things. 1 is that the whole "free market" thing is already a complete myth. 2 There is not necessarily any need for increased taxation. Just take the EXACT same subsidies already being spent and put them on renewables instead. Theorectically if you were a die hard "free market" guy you could even just lower taxation by eliminating Fossil-fuel consumption subsidies. Lower taxes to promote renewable energy seems quite an easy sell to Conservatives IMHO. It's way better than subsidizing fossil fuels, so should go over pretty well with Liberals too.

    The mistake of course being the premise is wrong. It's got nothing to do with conservative or liberal. It only happens because corrupt politicians need to repay the campaign contributions they received. quid pro quo.

    It is true that conservatives SELL  this as their attempts to keep taxes and regulations down. The liberals SELL this as a needed increase in taxation and regulation. The truth is it is EXACTLY the opposite. The ONLY  difference is which side of the aisle the spin doctors who write this kind of propaganda are working with. Liberals like to hear liberal slanted spins, and conservatives like to hear conservative slanted spins. Nothing more than confirmation bias from both sides.

  49. How climate science deniers can accept so many 'impossible things' all at once

    Good points. I have seen climate change sceptics make these contradictory arguments in books and articles, and they are dumbfounding.They either dont have the wit to see they are being contradictory, or they just don’t care. It’s war by throwing as much mud as possible hoping enough will stick.

    The basic climate scepticism may have various origins. As the article says, some people promote small government and are anti government regulation almost by instinct, and this possibly colours their views against emissions taxes etc, and so they try to discredit the science. I think their unconscious world view is colouring their immediate reactions to the science.

    However anti government regulation agendas have a political, business and ideological basis only. Economists mostly accept markets dont adequately self regulate, to protect the environment and that laws are needed. Even Nixon sensibly introduced environmental laws.

  50. Climate inertia

    Climate Noob @9, @5 above I discuss the differences between the Transient Climate Response (TCR), Equilibrium Climate Sensitivity (ECS), and Earth System Response (ESS).  I also have a detailed discussion of the likelihood estimates of the values of the ECS in the IPCC AR5.  Looking at it in detail is very interesting, for it shows that according to the IPCC the most likely result is an ECS below 3 C, and indeed that the most likely single value (mode) may be below 2 C.  That is important if you are prone to give in to councils of despair given the plethora of bad climate news around.

    Importantly, however, the mean values of the ECS estimate are almost certainly just above 3 C.  In cost benefit analysis, it is typically the mean value that is the best indicator of the likely cost of the scenario.  If costs increase more than linearly with increasing temperature, the best indicator in a cost benefit analysis woud be from values above the mean.  It is somewhat like Russian Roulette.  The most likely value from a single round of Russian Roulette is no bullet in the head, but that one in six chance of blowing your brains out pretty much always makes Russian Roulette a round of Russian Roulette a stupid play.  Likewise with global warming, the most likely result has a moderate ECS and a reasonable probability of moderate harm; but the significant (if small) probability of truly catastrophic harms means if we are smart, we don't play the game, ie, we cease GHG emissions as quickly as is technically and economically feasible.

    What distinguishs the ECS estimates of the more reasonable climate skeptics is that they have a PDF which cuts of near 1 C as sharply as does the estimated IPCC PDFs, but also cuts of almost as sharply at or near 3 C.  That it, what distinguishes these skeptics is that they are far more certain of their result than are the IPCC.  That extra certainty is obtained by excluding a large number of emperical methods of determining the ECS, including all comparisons with past times, all assessments of modern temperatures except those by energy balance models; and of course, by excluding the non-emperical estimates based on the climate models.  In addition, they seem to use a number of controversial assumptions, all of which reduce the estimated ECS.  In short, what distinguishes them is a biased dogmatism most noteworthy for the quantity of information excluded from their estimates.   

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