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Unforced variations: Sep 2019

Filed under: — group @ 1 September 2019

This month’s open thread for climate science topics. A new two-part community assessment of tropical storms and climate change is online at BAMS: Knutson et al. (2019a ; 2019b). And for those interested in Arctic Sea Ice, there is always the NSIDC.


  1. T. Knutson, S.J. Camargo, J.C.L. Chan, K. Emanuel, C. Ho, J. Kossin, M. Mohapatra, M. Satoh, M. Sugi, K. Walsh, and L. Wu, "Tropical Cyclones and Climate Change Assessment: Part I: Detection and Attribution", Bulletin of the American Meteorological Society, vol. 100, pp. 1987-2007, 2019.
  2. T. Knutson, S.J. Camargo, J.C.L. Chan, K. Emanuel, C. Ho, J. Kossin, M. Mohapatra, M. Satoh, M. Sugi, K. Walsh, and L. Wu, "Tropical Cyclones and Climate Change Assessment: Part II: Projected Response to Anthropogenic Warming", Bulletin of the American Meteorological Society, vol. 101, pp. E303-E322, 2020.

278 Responses to “Unforced variations: Sep 2019”

  1. 251
    nigelj says:

    Al Bundy @226

    Mal Adapted: The WMO specifies a 30-year interval for establishing climate normals,

    AB: It’s amazing that rules of thumb continue to be given life long after the truism they rely on has been shatterered…..5 years seems about right to me, with the data cleaned up by subtracting ENSO, the sun, volcanoes, et al.

    Nigelj: I’m pretty sure they use 30 years because several ocean cycles like the PDO cycle have a long cycle of about 15 – 30 years, so we need to be sure such things are not behind a warming (or cooling) trend. This is why scientists were not flapping around too much over the so called ‘pause’. But the recent acceleration should still be getting our attention, ie it’s obviously a concerning thing.

    Sorry it I appear to be picking holes. Agree with the majority of your views.

  2. 252
    Killian says:

    Re #226 Al Bundy said Mal Adapted: The WMO specifies a 30-year interval for establishing climate normals,

    AB: It’s amazing that rules of thumb continue to be given life long after the truism they rely on has been shattered. As if 30-years is a short enough time to measure a climate normal. Like photographing a walker in the dark with a long exposure shot. One big smudge.

    5 years seems about right to me, with the data cleaned up by subtracting ENSO, the sun, volcanoes, et al.

    You’re thinking about this incorrectly, AB, getting it half right. I often talk about short-term events as being harbingers of change, and that is the use of short-term events: They indicate possible rapid changes/tipping points.

    However, one cannot dismiss the long-term trend as it is the confirmation that the short-term was what one thought it was. The error among the scienctific literati lies in dismissing the short-term too often and assuming the confirmation of the 30 years is necessary before stating a thing is what it is. In terms of risk, this may well be suicidal because tipping points/bifurcations are what they are, and when they shift, they do it suddenly. This means we must keep a very vigilant eye on them and be ready to run to high ground in a quick hurry.

    And so we end up back where I have long suggested we must start: Long-tail risk. That is defined by those short-term extremes. Ergo, they are actually vitally important to track and give weight to.

    I’ll remind all that this past January/Feb I noted some concern over the early high CO2 counts. It started with jsut two days. But they were anomalous, so I paid attention. This turned out to be a signal of a larger-than-expected increase in CO2 this year (which has since been confirmed as a now-multi-year acceleration/increase in CO2 emissions/concentration.)

    Yes, the extremes matter, and the short term matters.

    (The absence of info serves the same function at times. Before the IPCC IV(?) report in 2007, I read a comment by a cryosphere scientist – have never been able to find it again or remember who it was, but it was very much in the style and mein of J. Box – that ice dynamics were not included. It became a no-brainer that the estimate topping out at something like 39 centimeters by 2100 was absolute bullocks. Didn’t take much reading to conclude it would be much higher. At that time, Antarctica was still generally considered to be gaining mass or to be in balance. That couldn’t be right w/ what had already been happening in the Arctic for over 50 years.

    That turned out to be right and the teleconnections globally have since been found to be of shorter time frames than thought at the time. But, how could they not be? Looking at it systemically, they had to be shorter. And we had the Antarctic peninsula acting funny, etc.)

    We still cannot dismiss the long-term trend. Our short-term change may be part of a long-term trend slowly unfolding rather than the beginning of a rapid bifurcation. That every extreme event can be either is our great dilemma.

  3. 253
    Killian says:

    Re #209 nigelj said I suggest a new monthly thread called “Deliberate Ignorance: (Date) for most of the denialists stuff. It would un-clutter the UV and FR threads. Nobody likes being humiliated, so it might make the denialists improve. This is a simple workable plan.

    Principle: Least change for maximum effect.

    The Bore Hole already exists. As I suggesteed to AB, move *all* denialist claptrap there and open it to posting so those of you who still wish to can get down in the mud with them without the ongoing, significant reduction in the usefulness of this site.

    No need for moderation, so no time drain for whomever moderates.

  4. 254

    AB 226: As if 30-years is a short enough time to measure a climate normal. Like photographing a walker in the dark with a long exposure shot. One big smudge. . . . 5 years seems about right to me, with the data cleaned up by subtracting ENSO, the sun, volcanoes, et al.

    BPL: “seems about right to me” isn’t how they calculate such things.

  5. 255

    sh 227: Climate change is changing about the same rate as it always has

    BPL: No, it is changing much faster than usual. Don’t just make things up, homee, it’s too easy for people to check.

  6. 256
    Mal Adapted says:

    What impresses me most about Greta Thunberg is how she’s managed to get the public’s (or at least the media’s) attention, while it’s still on the last few years of record-breaking weather. A new encouraging sign is the “Covering Climate Now” initiative. As announced by the Guardian on Sept. 15th:

    This week, ahead of the UN climate summit on 23 September, the Covering Climate Now partners have pledged to increase the volume and visibility of their climate coverage in the first large-scale collaboration of the partnership. The Guardian is making a selection of its climate coverage available to partners for free to help publications without dedicated environment desks serve their audiences.

    In addition to the Graun, 250 media outlets including the likes of CNN and Nature are participating. I’m prepared to believe putting AGW above the fold more often will help. I’d just like it to go on for more than a week, lest climate reality sink below the din of denial again.

  7. 257
    nigelj says:

    Killian talks about the need for a better climate change risk analysis. I will give this challenge a go by quantifying the risks of climate change, and considering the possible solutions and their risks and benefits as I see it:

    First let’s summarise the basics, that are already well enough known to many people. If we keep burning fossil fuels many dozens of serious problems will eventuate according to the IPCC. For example by 2100 temperatures will almost certainly be at least 2 degrees higher than pre industrial, and could be 4 degrees c or more (according to the IPCC), sea level rise will almost certainly be at least half a metre, and could be 1 metre, even 2 metres or more in some other analyses, and significant parts of the world could very possibly be uninhabitable due to high temperatures. By 2200 – 2300 the probability of temperatures exceeding 4 degrees c becomes very high and the probability of multi metre sea level rise per century becomes very significant.

    It should be self evident to anyone that no amount of “CO2 is plant food ” will compensate for such problems. Ie, the upsides of climate change are rather limited and of course many formal analysis attests to this eg by NASA.

    Now the more nuanced stuff. Economists have tried to assess climate risks and put costs on them, and do cost benefits analyses of mitigation, eg Nordhaus. While they find climate change will cause significant costs, their estimates look too low because the focus has been narrow, and many things are left out completely or treated in a tokenistic way and they more or less ignore the possibility of abrupt and severe climate change. The following is a good critique:

    Given the effects of climate change are so huge and negative, and we only have one planet, even a small possibility of very serious problems takes on a considerable weight, much like with cancer. This point is largely ignored by the economics community.

    The probability of scientists being wrong about the seriousness of climate change does not seem high. A lot of work has gone into this thing, and much evidence suggests the IPCC is if anything a bit conservative in its findings, although this is understandable. Scientists have largely had a good track record in the past with assessing other problems and it is mostly the media that have hyped or misrepresented past problems. Many problems have been quietly solved behind the scenes, leaving a false impression with some of the public that they were hype (eg Ebola, The Bird Flu, Y2K, The Ozone Problem)

    The solutions to the climate problem include various well known alternatives of mitigation, adaptation, sucking emissions out of the air with fans, developing natural carbon sinks, geoengineering, or smaller population (essentially a type of both mitigation and adaptation). Sucking CO2 out of the air, geoengineering, adaptation costs and population trajectories involve considerable risks, or challenges or unknowns at this stage.

    Reducing use of fossil fuels by substituting renewable energy, lifestyle changes and use of natural carbon sinks are more known quantities with benign side effects and reasonable economics, so should be the primary focus (although not the only focus and getting population growth down is a powerful tool). Lifestyle changes do not have to be punitive, but if we fail to act within the next few years it will become increasingly punitive, all other things being equal. Wind towers etc do use a lot of resources, so the less energy we waste the fewer we will need.

    There is a known high probability risk that humanity will run out of economically recoverable fossil fuel reserves sooner than many people think, and middle range estimates are 50 – 100 years , and this will require developing alternatives, so right now we are only delaying the inevitable.

    There is a risk we are wrong about the potential seriousness and extent of climate change but this looks like a small risk to me. The price we will pay if we have got this thing wrong looks like some manageable personal sacrifices that could well turn into positives, and an electricity system that uses free energy sources like the sun and the wind and is estimated to cost about 2% of a countries gdp per year to develop, and electric cars which are nice to drive and cleaner, and perhaps a better public transport system. The oil reserves would still be there if we need them for whatever purpose. Of course some projects could turn out to be a waste of time and money but at face value it just doesn’t look like a hugely significant burden in terms of scale within the whole economy. So the price we will pay if things don’t turn out to be serious does not look too large enough to be much of an issue.

    This is a brief personal take on things, and I suspect I have missed some risks.

  8. 258
    Al Bundy says:

    AB 226: As if 30-years is a short enough time to measure a climate normal. Like photographing a walker in the dark with a long exposure shot. One big smudge. . . . 5 years seems about right to me, with the data cleaned up by subtracting ENSO, the sun, volcanoes, et al.

    BPL: “seems about right to me” isn’t how they calculate such things.

    AB: They? Seems like Foster and Rahmstorf took an approach similar to mine. Of course, those who don’t believe in the integration of various data streams, those who believe that ONLY surface temperature should be used to contemplate surface temperature norms and trends without any consideration for environmental and other factors, who deliberately places themselves in the dark, WILL have to consider a way long period of time to try to develop a picture. Of course, such a long exposure totally prevents an informative answer.

  9. 259
    Al Bundy says:

    Killian: Principle: Least change for maximum effect.

    AB: Principle: When a system was built with essentially zero thought or effort (the comments at RealClimate are surely whenever-it-was’s-freebee-default-comment-section), to use said “system” as a basis for a future release is dumb as dirt, especially when the effort involved for the development of said future system will be done by folks who are chomping at the bit and FREE. Yada yada yada “least change” is irrelevant.

  10. 260
    Al Bundy says:


    The issue is that the rate of change in the signal has increased so much that a significant change in the signal currently occurs in a shorter period of time than the period of time needed to smooth the noise. This is kinda the opposite problem that climate scientists used to deal with: that the signal hadn’t risen above the noise.

    The only reasonable approach is noise-cancelling “headphones”. The goal is to reduce the required period to determine a climate norm to one second. (We’ll take five years for now.)

  11. 261
    Al Bundy says:

    nigelj: Scientists have largely had a good track record in the past with assessing other problems

    AB: Why not use THIS problem as a metric? Scientists have failed dismally in the direction of rating climate change as being too benign (less devastating). “It’s worse than we thought” didn’t become a mantra because scientists have been doing grandly. They’ve obviously been tuned by some sort of bias or systemic error. Methinks it’s the psychological abuse administrated by the GOPpers.

  12. 262
    Chuck says:

    Weaktor “the Dumber” says – The debate is over and it’s been won by those most adept at influencing public opinion.”

    You can learn a lot more free of charge by accessing the “Look Inside” feature at the Amazon site.

    Chuck – Reality is most adept and influencing public opinion even though idiots like yourself choose to ignore it. Go sell your shit elsewhere. Nobody here is stupid enough to buy it.

  13. 263
    nigel jones says:

    Mal Adapted @259 says “What impresses me most about Greta Thunberg is how she’s managed to get the public’s (or at least the media’s) attention, while it’s still on the last few years of record-breaking weather.” Probably coincidence, but shes certainly impressive. Imho she’s getting peoples attention because she keeps the issues simple and facts based, points out the hypocrisy of the adult world, is young so isn’t tainted by politics, and has avoided politicising her own rhetoric.

  14. 264
    O. says:

    @BPL, #257: I appreciate your articles.
    But in the article, you mentioned, there are links that do not work.
    They work, if changing “bartonpaullevenson” to “bartonlevenson”, so it looks like you changed the Site-URL, and forgot to chnage the links in your articles.

  15. 265
    O. says:

    @BPL, #257, 2nd answer:
    I wonder if there is not even a problem with too long periods.
    The data is not constant value + noise. It’s a changing target.
    So, how can a changing climate be identified by an average over a possibly too long period of time?
    If I interpret your calculations correctly, you always started with the year 2008, then calculated the stddev backwards with 5, 10, 15 years intervall size and so on.
    Lowering of the stddev might come from a rather more or less constant value + noise between 1925 and 1975, compared to more or less linear trend + noise.

    What if shifting the middle point of the averaging interval as well as changing the width of the interval? How would the results look then?
    Would be interesting, I guess.

    The problem is that looking for the best averaging time-interval for detecting a settled climate would need to have a settled climate, and then look at typical stddev-values.
    But the moving target of a changing trend beyond the noise will make the results less precise. Something like the Schleppabstand (german term from control engineering; don’t know the english term), dynamic error of a control system.

    Possibly a smaller averaging-intervall would make sense then.
    Or calculating the trend out of the data before?
    Other idea: select the rather flat region I mentioned above, find the middle and then widen the averaging-interval until it stabilzes more or less.
    If the stddev at some point grows instead of shrinking, this could indicate either higher noise, or the beginning of a change in the underlying trend (e.g. warming trend).

    Not sure on the best way at the moment, just thinking loudly about it.
    Interesting problem to think about. But possibly would need some more math.

  16. 266
    Mr. Know It All says:

    Democrat Governor Bullock of Montana: “Global warming is over, the evidence is in, we are going into a new ice age.”/s


  17. 267
    Russell says:

    Mal, what in ther name of all things bipartisan could possibly go wrong with 250 science journals & newspapers of record, including Nature, Science, The Indy and The Graun lining up behind the lead climate gurus of Vanity Fair and the Nation Institute?

    Mark Hertsgaard is both:

  18. 268
    zebra says:

    #257 BPL,

    It depends, as always, on what the question is. I remarked to AB previously that the science has matured, which I think is his point about incorporating other factors and forcings in the analysis.

    So, if we start with the fact that the increase of CO2 causes an increase in the energy in the climate system, we can state conclusions with data that doesn’t exactly meet the statistical test, based on our current characterization of the system.

    If you compare a decadal GMST average to the previous decadal average, say, and the result is consistent with our expectations, I would say we can be appropriately comfortable that our modeling is sound (albeit not perfect).

    What would the question be if you said: “But wait, that doesn’t necessarily preclude natural variation.” ??

    Is it that “Maybe all the physics, and all the other measurements and observations are wrong, how can you be sure?” ??

    If, on the other hand, we saw a drop in GMST based on those decadal averages, it would be reasonable to put some time into further analysis… Tamino could do his thing, and others could check the other physical inputs to be sure we hadn’t missed something, as with “the pause”.

    But, that does not mean accepting the Denialist framing and cherry-picking. It would have to be made clear that such a result fits within the existing theoretical framework. That’s what we do in science when we have an established Theory.

  19. 269
    MA Rodger says:

    The climate denialist petition which gained 506 signatories of various dubious ilk from 13 EU countries (although if bonkers Boris has his way that will be from just 12 EU countries after 31/10/19) and 10 non-EU countries (again potentially requiring a Boris adjustment) was prompted by the formation of The Climate Intelligence Foundation (CLINTEL) by a couple of Dutch climate denialists.
    Not content with this level of denialist claptrap, the bunch now plan to form the Global Climate Intelligence Group (although this screed from Viscount Monckton says it is already ‘founded’). This group plans to set up their own on-line open-access journal called “Journal of Corrections” perhaps this name covering both bases – that they somehow manage to occasionally ‘correct’ the findings of the usual scientific process or (more likely) that it will feature work that will be the subject of innumerable corrections.
    There is also blather about holding national and international conferences where they can get their silly theorising into the media, and also of financial assistance for the denialists who find their views incompatible with the institutions/organisations that employ them. They even talk of setting up an on-line university and internet-based education for any youngersters (as young as 3) unfortunate enough to find themselves assocuated with this deluded flock. Of course, just in case this brain-washing of youngsters proves to be difficult to control:-

    “All teachers, lecturers, professors and students in the new network of schools and universities will sign a binding contract with the holding corporation. That contract will govern their conduct, and will in particular forbid them, on pain of expulsion, to interfere in any way with freedom of academic inquiry, research, thought, speech or action.”

    Now that would be an interesting set of principles to uphold, “on pain of expulsion.”

  20. 270
    Alastair B. McDonald says:

    BPL @222 You wrote:

    ABB 213: The short-wave radiation from the Sun only heats the surface of the Earth, not the air.
    BPL: No, there is plenty of absortion of sunlight by the atmosphere, though mostly by clouds.
    ABB: Back radiation only produces a small positive feedback; it is not the driver of the greenhouse effect.
    BPL: Yes it is. Stop spreading nonsense.

    Your slogans don’t deserve a response, but if I don’t then no doubt you will think you have won the argument, just as Hank did several years ago with his meaningless slogan.

    You can’t even get my initials correct, and it is obvious you have not read Saussure’s chapter. You are like the priests who refused to look through Galileo’s telescope, frightened of seeing the truth.

    The whole principle of the greenhouse effect is that it is the absorption of long-wave radiation from the Earth’s surface by greenhouse gases which warms the air. If solar radiation was absorbed by air it would not reach the surface, in fact, that is what happens to the UV radiation.

    Greenhouse gas molecules do not emit black-body radiation back to the surface. If they did then they would be unable to emit it to space and balance the energy flow at the TOA.

  21. 271
    Killian says:

    Dear Moderator(s)/Site Owners,

    I strongly encourage a new Forced Responses be opened ASAP. Last cycle we were left without a FR for a month or more and the quality of the Unforced Variations went through the floor.

    Maybe let’s not repeat that…?


  22. 272
    Rex Tasha says:

    The totalitarians are out in full force. Off to the borehole with you!

  23. 273
    James Charles says:

    “Sep 22, 2019, 12:00am
    No One Seemed To Notice Greta Thunberg’s Critique Of The Green New Deal

    Jeff McMahon Contributor “

  24. 274
    MA Rodger says:

    Another month, another 12-month CO2 increase to add to the data.
    So how are my grand projections of MLO CO2 increases stacking up? They are graphed out here (usually 2 clicks to ‘downlod yor attachment’) and tabulated below. (Model explained in August’s UV thread.)

    12-Month MLO CO2 increase.
    … … … … …Modelled… … … … ..Actual… … … .. ..Actual
    … … … .[Original,Smoothed]… ..[Unsmoothed]… ..[Smoothed]
    Jan19 … … … 2.74 … … … … … … 2.87 … … … … 2.85
    Feb19 … … … 2.92 … … … … … … 3.43 … … … … 2.95
    Mar19 … … … 3.13 … … … … … … 2.56 … … … … 3.02
    Apr19 … … … 3.10 … … … … … … 3.08 … … … … 3.02
    May19 … … … 3.16 … … … … … … 3.42 … … … … 3.21
    Jun19 … … … 3.24 … … … … … … 3.13 … … … … 3.20
    Jul19 …. … … 3.07 … … … … … … 3.06 … … … … 3.05
    Aug19 … … … 2.94 … … … … … … 2.96 … … … … 3.01
    Sep10 … … … 2.78 … … … … … … 3.00
    Oct19 … … … 2.66
    Nov19 … … … 2.44
    Dec19 … … … 2.13
    Jan20 … … … 2.07
    Feb20 … … … 2.06
    Mar20 … … … 1.87

  25. 275
    mike says:

    Troy Vettese argues that effective action to stop global warming will require fundamental changes in the way we use the land surface of the planet. Listen if you have an hour:

    How is it going on global warming? The warming is simply accelerating in response to the CO2e load we have established. It ain’t rocket science: More CO2e, more heat.

    September 22 – 28, 2019 408.32 ppm
    September 22 – 28, 2018 405.63 ppm
    September 22 – 28, 2009 384.73 ppm

    Those are the CO2 numbers from

    Warm regards,


  26. 276
    Richard Creager says:

    Moderators. Is there any bar to comment acceptance? By exactly what editorial criteria does 201 see print? Is this thread for advancing the discussion of “climate science topics”, or unadulterated personal denigration and character assassination. Regardless of the quality or lack thereof of Victor’s comments, there’s no place for that. Please! Just Borehole it.

  27. 277
    MA Rodger says:

    UAH has posted for September with a TLT anomaly of +0.61ºC, the highest UAH TLT anomaly of 2019 so far and by some margin. (They previously spanned from +0.47ºC down to +0.32ºC.)

    It is the warmest September on the UAH TLT record ahead of 2017 (+0.55ºC), 2016 (+0.46ºC), 1998 (+0.44ºC), 2010 (+0.38ºC), 2009 (+0.27ºC) and 2015 & 2005 (both +0.25ºC).
    It is the 8th highest anomaly on the all-month UAH TLT record, sitting behind three 1998 months, three 2016 months and (all El Nino boosted) & Oct 2017.

    Now with three-quarters of the year complete, 2019 sits in 3rd place for the year-to-date. To drop to 4th place by end-of-year behind 2017 would require Oct-Dec to average less than +0.30ºC which would be extremely unlikely. To gain 2nd place in the trend-defying UAH would require Oct-Dec to average +0.71ºC (which would have been seen as impossible prior to the high Sept anomaly being posted).

    …….. Jan-Sept Ave … Annual Ave ..Annual ranking
    2016 .. +0.56ºC … … … +0.52ºC … … … 1st
    1998 .. +0.56ºC … … … +0.48ºC … … … 2nd
    2019 .. +0.41ºC
    2010 .. +0.40ºC … … … +0.34ºC … … … 4th
    2017 .. +0.35ºC … … … +0.38ºC … … … 3rd
    2002 .. +0.24ºC … … … +0.22ºC … … … 7th
    2015 .. +0.22ºC … … … +0.27ºC … … … 5th
    2018 .. +0.22ºC … … … +0.23ºC … … … 6th
    2005 .. +0.20ºC … … … +0.20ºC … … … 8th
    2007 .. +0.20ºC … … … +0.16ºC … … … 11th
    2014 .. +0.16ºC … … … +0.18ºC … … … 10th

  28. 278
    CCHolley says:

    Alistair B. McDonald @273

    Greenhouse gas molecules do not emit black-body radiation back to the surface. If they did then they would be unable to emit it to space and balance the energy flow at the TOA.

    What? This is utter nonsense. Greenhouse gas molecules radiate heat in all directions equally. They have no idea of up down right or left. Thermal equilibrium occurs when the energy radiated into the earth system equals the energy radiated out. Per the Stefan-Boltzmann law knowing the solar constant and surface area giving the energy into the earth system this equilibrium occurs with the radiation generated from a temperature of 255 degrees Kelvin. Since greenhouse gases inhibit the radiation from escaping freely to space from the surface that temperature must move from the planet surface to somewhere up in the atmosphere where the density of greenhouse gases is such that the portion of the radiation emitted upward can then escape freely to space without reabsorption. This in turn results in a warmer surface from the portion of the radiation emitted downward.

    BTW, 16 per cent of solar radiation is absorbed by water vapor, dust, and O3 in the atmosphere. 3 per cent is absorbed by clouds. BPL knows what he is talking about. You do not.