Another CMIP6 climate sensitivity constraint

I thought I would follow up yesterday’s post with one that highlights another paper that looks at CMIP6 climate sensitivity. It’s a paper by Femke Nijsse, and colleagues, and considers [a]n emergent constraint on Transient Climate Response from simulated historical warming in CMIP6 models. The basic idea is to use the warming since the 1970s to constrain the transient climate response (TCR).

Credit: Nijsse et al. (2020)

The figure on the right illustrates the basic constraint. The light grey vertical band is the observed warming since 1975. The darker grey horizontal band shows the range of TCR values from models that satisfy this constraint. This result suggests a likely TCR range of 1.5K to 2.2K, with a best estimate of 1.8K.

Credit: Nijsse et al. (2020)

The figure below shows the TCR plotted against the ECS, for each of the models considered. Models with TCR values between 1.5K and 2.2K, can have ECS values that range from ~2K, to ~5K. So, although this analysis might suggest a better constrained TCR, it doesn’t particularly constrain the ECS.

Something I did wonder (which maybe someone else can clarify) is if this implied anything with respect to carbon budget estimates. Carbon budgets are typically estimated using the Transient Climate Response to Cumulative Emissions (TCRE). According to this paper (H/T Femke Nijsse) the TCRE for the CMIP6 simulations is 1.8K ± 0.4K per 1000 GtC. The reason this can then be used to estimate the carbon budget is that there is essentially no warming committment; global temperatures are expected to stabilise when emissions cease.

However, I think (although I’m not sure) that this does depend somewhat on the TCR-to-ECS ratio, which is typically thought to be about 0.6. However, if it’s possible that the ECS is more than twice the TCR, would we still expect global temperatures to stabilise when emissions cease? If not, would this then imply that carbon budget estimates could be too low? I don’t know the answer, so will stop there.

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139 Responses to Another CMIP6 climate sensitivity constraint

  1. Everett F Sargent says:

    So, at the end of the ECS day, WGI decides that it is likely that 2C < ECS < 5C or in their three conditionals format …

    (1) p <= 0.05 that ECS = 0.66 that 2C < ECS < 5C
    (3) p 5C

    Or some such.

  2. “would we still expect global temperatures to stabilise when emissions cease?” I know there is some math behind this expectation, but it always seemed like wishful thinking to me because there are too many positive feedbacks/tipping points that we will blow past before we get to test the theory that temps will stabilize with emissions. How many lukewarmist angels can dance on the head of a pin? Another question that we probably can’t answer with certainty. The emission question seems more important to me, but both seem quite hypothetical.

  3. Everett F Sargent says:

    Scratch that last comment due to formatting issues.

    So, at the end of the ECS day, WGI decides that it is likely that 2C < ECS < 5C or in their three conditionals format …

    (1) p less than 0.05 that ECS less than 2C
    (2) p greater than 0.66 that 2C less than ECS less than 5C
    (3) p less than 0.1 that ECS greater than 5C

    Or some such.

  4. Everett F Sargent says:

    One more time with gusto (everything moves up by 0.5C) …

    (1) p less than 0.05 that ECS less than 1.5C
    (2) p greater than 0.66 that 2C less than ECS less than 5C
    (3) p less than 0.1 that ECS greater than 6.5C

  5. John Hartz says:

    ATTP: Any chance you could edit the OP by blowing up the two graphics to full page width?

  6. Everett F Sargent says:

    JH,

    Open them up in a new window. Then you will see that both are uge, bigly uge.

  7. MarkR says:

    Back of the envelope maths for TCR:

    1) Fit a LOWESS to the global T series, get total warming ~1.1 C
    2) Work out how much CO2-equivalent we’re at right now. AR5 diagram says non-CO2 is 0.6 W m-2 or +35 %, equivalent to about +60 ppm right now.

    So let’s say we’re at 1.1 C warming after 470 ppm CO2 equivalent (410 ppm CO2, +60 equivalent from other stuff). Then make whatever other assumptions you want to guess the real world TCR. If everything else balances out and CO2 increases at 2.5 ppm/year, we hit 560 ppm CO2eq in 36 years. In that case, continued present warming rates take us to 1.8 C.

    So Femke’s numbers pass the sniff test. By contrast a number as low as 1.3 C doesn’t make too much sense unless some very surprising things happen.

  8. Steven Mosher says:

    while we shouldn’t overweight 1 study, there is this
    https://eartharxiv.org/me5uj/

    which also gives you a constraint

  9. David B. Benson says:

    I don’t understand this:
    https://m.phys.org/news/2020-01-rethinking-climate-hotter-temperatures.html

    What is he attempting to state?

  10. Steven Mosher says:

    ATTP the paper is a model of clarity in exposition.

  11. John Hartz says:

    Everett F Sargent: Thanks. I should have caught that feature.

  12. Chubbs says:

    Like MarkR, took a crack at checking the paper # using the same periods 1970-80 and 2008-18 and CMIP5 forcing data from Dessler and Forster (2018).

    Delta Forcing (period 2 – period 1) – 0.37 2xCO2

    TCR estimated by Delta T/Delta F (Delta T in paren below):
    GISS – 1.87 (0.70)
    BEST – 1.78 (0.67)
    Hadcrut – 1.69 (0.63)
    HadcrutCW – 1.79 (0.67)

    The estimates above line up well with the paper result. Also shows that the CMIP5 ensemble mean of 1.83 is in good agreement with TCR estimated from observed warming since 1970.

  13. John Hartz says:

    Is there a core set of GCMs that have been used in the ensembles created for each AR cycle?

  14. MarkR,
    Yes, something around 1.8K makes sense. Something around 1.3K is much harder to regard as reasonable (unless some very strange things are, or will, happening).

    Steven,
    That is a nice paper, but it’s constraining ECS, rather than the TCR. Is that what you were getting at?

  15. JH,
    I think there are a set of guidelines for those who would want their GCMs to be included. I don’t think that there is then another stage where GCMs are then excluded if they don’t satisfy some other constraints. Others probably know more about this than I do, though.

  16. David,
    I’ve only just glanced at that paper, but I think it’s to do with what will happen when we cease emissions. Something I’ve stressed quite a lot is that there probably isn’t much of a warming committment; when we cease emissions, global surface temperatures should stabilise. However, the land warms faster than the oceans. Hence, even though global temperatures will stabilise when we cease emissions, there will be some adjustments as the oceans continues to warm, and the land cools slightly. Hence, by focussing on global mean temperatures, we may be somewhat under-estimating the amount of transient warming that many will experience.

  17. David B. Benson says:

    aTTP — Thank you but I am still bamboozled.

  18. David,
    Why does it bamboozle you? I have just read the paper a little more and this bit explains it quite nicely.

    For most land areas of the world, the average boreal summer (June–August (JJA)) and winter (December–February (DJF)) temperatures are substantially higher in the transient climate relative to the equivalent quasi-equilibrium climate with strong model agreement. This is especially true in boreal summer over continental climate zones in the Northern Hemisphere (Fig. 2a,b). By contrast, over the Southern Ocean and the North Atlantic, there are large areas where a quasi-equilibrium climate is on average at least 0.5 °C warmer than the equivalent transient climate. In the quasi-equilibrium world, the passage of time has resulted in heat redistribution such that the land regions are cooler and the extratropical oceans are warmer14,18. This result aligns with previous research showing that ocean warming lags behind warming over the land surface19.

  19. Steven Mosher says:

    “Steven,
    That is a nice paper, but it’s constraining ECS, rather than the TCR. Is that what you were getting at?”

    yes. I think there is a strong argument to make ( al hansen) that paleo estimates ( in particular the LGM) are pretty hard to beat constraints on ECS: mainly because they include all physics, something we can only assume about models.

    It might be time to drop the democracy of models and adopt the meritocracy.

  20. Steven,

    yes. I think there is a strong argument to make ( al hansen) that paleo estimates ( in particular the LGM) are pretty hard to beat constraints on ECS: mainly because they include all physics, something we can only assume about models.

    Yes, I agree. As I read it, the study you highlighted also suggests a range from 2K – 4.5K. It does seem as though the CMIP6 GCMs that are suggesting an ECS above 4.5K are outliers.

  21. Greg Robie says:

    The assertion that there is no committed warming once [anthropogenic] emissions [hypothetically] cease assumes the omitting the cryosphere – as Solomon et al & Ricke/Caldeira & SR15 do – is a valid assumption [on a century time scale].

    Why are you are yet a ‘sock puppet’ for this?

    The latent heat of the annual Arctic sea ice loss is currently 5 x 10^21 J. Such will be an ongoing addition once that “stored” cold is not created on an annual basis. And this is only part of the cryosphere’s stored cold that is diminishing. And/or, it may be less clouds in the southern extatropics + increased seasonal Arctic refraction and twilight + … ?

    sNAILmALEnotHAIL …but pace’n myself

    https://m.youtube.com/channel/UCeDkezgoyyZAlN7nW1tlfeA

    life is for learning so all my failures must mean that I’m wicked smart

    >

  22. Tony McLeod says:

    MarkR says:
    So let’s say we’re at 1.1 C warming after 470 ppm CO2 equivalent…

    Is it only 1.1 C though. There is evidence of up to a -1C aerosol masking plus a potential lag of 10 years for the maximum effect of a given emission. I make that about 2.3C after 470 ppm CO2 equivalent…less than half way to a doubling.

    Shoot it down, please.

  23. Tony,
    I think that Mark’s calculation roughly takes that into account. The net change in forcing (CO2 + short-lived GHGs + aerosols) is probably around 2.5 W/m^2. If we’ve warmed by about 1.1K, then the TCR would be

    TCR = \dfrac{1.1}{2.5} \times 3.7 = 1.6K.

    A bit lower than Mark’s result. If the aerosol forcing is indeed a bit bigger, then this would go up a bit, but probably not enough to get it to 2.3K.

  24. Chubbs says:

    This is a very nice paper and I like using temperature response as the constraint. What could go wrong? Pattern effects come to mind. Several papers have argued that pattern effects have reduced observed warming vs model predictions. If the observed pattern is transitory then can’t use observations to rule out higher sensitivity..

  25. Steven Mosher says:

    “Yes, I agree. As I read it, the study you highlighted also suggests a range from 2K – 4.5K. ”

    CMIP5 models I recall were 2.1 to 4.4 or so. (maybe 4.5, memory fails me)

    basically I always looked at the model as uninformative about ECS, that you probably shouldn’t use then to constrain or expand the range, but if they fell outside the paleo ranges then something might be wrong with them, and that’s because of Hansen’s argument that paleo includes all the physics.

  26. JCH says:

    SM – there is this dismissal by frankclimate:

    Here is a history of the model’s various ECS’s and the IPCC range:

    This is their reference for the model they used.

  27. John Hartz says:

    ATTP: It is my understanding (possibly in error) that the number of GCMs included in AR6 is more than were included in AR1, If there is a core group of models that have been used in each AR iteration, is it possible to ascertain whether one has consistently performed better than the others and better then the ensemble over time? Perhaps such determinations can only be made with a Time Machine.

  28. Steven Mosher says:

    Im afraid models have become more than a heuristic tool used to gain understanding.
    If they take on more policy relevance, tighter controls would be the ordinary and standard thing to do. that would mean formal IV&V

  29. MarkR says:

    John Hartz,

    There are a set of institutes whose models have been in a bunch of IPCC reports. But the changes from one version to another can be so big that I’m not sure just how useful it would be to say something like “well we trust CESM2-CAM6 because CESM1-CAM5 did well at this”.

    I see these “emergent constraints” as close to what you’re describing though. They effectively give more weight to models that simulate one process better than the others. In CMIP5 most of the constraints kept picking the same set of (high ECS) models.

  30. John Hartz says:

    MarkR: Thank you for the explanation.

  31. John Hartz says:

    An example of how new research findings are incorporated into a GCM is nicely described in…

    Antarctic Waters: Warmer with More Acidity and Less Oxygen by Mari N. Jensen, UA News, Jan 6, 2020

  32. angech says:

    ATTP ” I think it’s to do with what will happen when we cease emissions. Something I’ve stressed quite a lot is that there probably isn’t much of a warming commitment; when we cease emissions, global surface temperatures should stabilize. However, the land warms faster than the oceans. Hence, even though global temperatures will stabilize when we cease emissions, there will be some adjustments as the oceans continues to warm, and the land cools slightly.”

    How does this square in with your assertion that warming will continue to increase for up to a millennium due to the persistence of CO2 in the atmosphere despite stopping emissions?
    Confused.

  33. angech says:

    According to this paper (H/T Femke Nijsse) the TCRE for the CMIP6 simulations is 1.8K ± 0.4K per 1000 GtC. Can anyone translate this into ppm CO2 for comparison?

  34. angech,

    How does this square in with your assertion that warming will continue to increase for up to a millennium due to the persistence of CO2 in the atmosphere despite stopping emissions?

    I’ve never asserted that. In fact, I’ve had numerous posts pointing out that global warming will roughly cease when we stop emissions. Global temperatures won’t go down, but the uptake of CO2 by the oceans will roughly cancel the continued warming.

    According to this paper (H/T Femke Nijsse) the TCRE for the CMIP6 simulations is 1.8K ± 0.4K per 1000 GtC. Can anyone translate this into ppm CO2 for comparison?

    Well, according to the same paper, doubling atmospheric CO2 from 280ppm would require emitting around 1100 GtC. So, 1000GtC is a bit less than doubling atmospheric CO2.

  35. dikranmarsupial says:

    Steven Mosher wrote “Im afraid models have become more than a heuristic tool used to gain understanding. If they take on more policy relevance,”

    IIRC the IPCC range on ECS is not based solely on GCMs, but also on paleoclimate work and other forms of estimate, none of which have more quality control/assurance applied to them than the GCMs do. It is fine to want more IV&V, but who is going to pay for it, and what could those funds support instead of IV&V? The development of GCMs by different competing modelling groups is already a form of IV&V, as are the *MIPS exercises.

    The policy problems have little to do with the science anymore, and haven’t for some time. The real problems are social, political and economic. If we really should have more IV&V it should be there (especially the politics).

    IMHO, of course ;o)

  36. angech says:

    ATTP.
    Thanks x2.

  37. Willard says:

    > that would mean formal IV&V

    The creators of DICE and FUND will be pleased to hear.

  38. Mal Adapted says:

    Steven Mosher:

    Im afraid models have become more than a heuristic tool used to gain understanding.

    That’s the thrust of the Dec. 2 PNAS Perspective by Palmer and Stevens I mentioned in the previous thread:

    Whereas present day climate models were fit for the purpose for which they were initially developed, which was to test the basic tenets of our understanding of global climate change, they are inadequate for addressing the needs of society struggling to anticipate the impact of pending changes to weather and climate.

    SM:

    If they take on more policy relevance, tighter controls would be the ordinary and standard thing to do. that would mean formal IV&V

    Heh. FWIW, I’m in favor of applying software engineering standards to GCMs that are intended to inform detailed policies. But Palmer and Stevens call for more than that, in rather “windy” terms:

    If climate science aspires to be relevant to societies dealing with climate change, a new strategy (17) is required (Box 2). A fresh wind, in the form of a step change in the physical content and fidelity of climate simulation systems, must be let loose to fan the flame of basic climate science to challenge our understanding of how global warming becomes manifest in regional climate and its subsystems. The stirrings of such a wind are beginning to be felt, as in different laboratories around the world, experimental efforts aimed at harnessing exascale computing to surmount roadblocks, known to limit the fidelity of existing simulation systems, are taking shape (18–21). However, if these stirrings are to grow to the gale required to give impetus to theory and observations and if society is to fully realize the ensuing benefits, these efforts must be scaled up through bold, sustained, and coordinated multinational initiatives.

    Whew! Of course, all that will take a lot of money. P&S again:

    Now that the blurry outlines of global climate change have been settled, the need to sharpen the picture (Box 1) has become more urgent (2). However, such sharpening is proving to be more challenging than anticipated—something that we attribute to the inadequacy of our models (3–5). Unfortunately, many in the community—notably those in charge of science funding—have no idea how significant and widespread these inadequacies are.

    A concurrent item on phys.org, bylined only “University of Oxford”, is titled A CERN for climate change. While I’m certainly in favor of that too, complaints about funding are no doubt familiar to all experienced investigators. IMHO we can’t wait for more accurate, detailed model results before taking collective action at the national level, to internalize at least a low-end estimate of the marginal social cost of carbon.

  39. Mal Adapted says:

    Lest I appear to make unsupported claims: once again, I’m reasonably certain we can’t wait for better models before acting collectively, because (Palmer and Stevens again):

    All one needs to remember is that confidence in the big picture is not primarily derived from the fidelity of comprehensive climate models of the type used to inform national and international assessments of climate change.

  40. John Hartz says:

    Mal Adapted:

    Spot on.

    The fact that the Earth’s biosphere is going to hell in a handbasket faster than anyone thought possible ought to be causing the human race to act swiftly, decisively, and collectively.

  41. Ben McMillan says:

    Actually, the funny thing is that places that the UK Met Office (which has a well-known GCM) is regarded as world-leading on stuff like IV&V, uncertainty quantification and so on. UK numericists in other fields regularly go and ask the Met Office how to do these things.

    They are paid a lot of money to produce and run reliable software with low and well-quantified errors because they are good at it.

    So the regular claims that climate scientists make poor predictions because they aren’t any good at software engineering is getting towards being maximally wrong.

    Maybe the level of uncertainty is because climate is a particularly gnarly problem?

  42. John Hartz says:

    Asking from a place of ignorance, what is “IV & V”?

  43. what JH said is logical:

    “The fact that the Earth’s biosphere is going to hell in a handbasket faster than anyone thought possible ought to be causing the human race to act swiftly, decisively, and collectively.”

    and I wonder why doesn’t that happen? I think it doesn’t happen because we don’t function as a race, we function as social groups with a long history of competition over various resources. This gamesmanship between social groups seems to be something that our species may not be able to overcome.

    The demonization of others promises big rewards for the winners. Building genocidal energy to wipe out other populations of our species has a lot of traction within modern human culture. Even the term you used, race, is fundamentally a social construct, not a biological reality, and that construct also has a lot of history and traction in the realm of competition and genocide over cooperative planning and coexistence.

    How do we overcome this history and programming? I think we talk about our collective possibilities if we cooperate and contrast those with our collective possibilities if we continue to choose competition and extermination of competitors. It’s a big hill to climb, but what else do we have to do with our time?

  44. The Very Reverend Jebediah Hypotenuse says:


    The fact that the Earth’s biosphere is going to hell in a handbasket faster than anyone thought possible ought to be causing the human race to act swiftly, decisively, and collectively.

    Fear not.
    The human race is on the brink of a econo-socio-cultural paradigm shift, and will be undertaking the required Herculean labours any decade now.

    Why, just this week, a growing list of celebrities have pledged to donate – including Chris Hemsworth, Elton John, Nicole Kidman, Pink, and Keith Urban.. Even the bad-boys of Metallica announced a donation on Tuesday night to a firefighting agency and emergency services agency.

    ‘Tis nothing that a few celebrity-sponsored water-bombers can’t handle.

  45. John Hartz says:

    A plausible explanation of why some people do not act on climate change is described in…

    How the bystander effect can explain inaction towards global warming by Gerdien de Vries, LSE Business Review, Jan 7, 2020

  46. Ben McMillan says:

    “Independent Verification and Validation”. The V&V bit is making sure the codes do what they are designed to do, and also that they produce correct output (because the specification might be wrong). The independent bit is making a third-party do the V&V.

  47. John Hartz says:

    Ben McMillan: Muchas gracias.

  48. Steven Mosher says:

    “While I’m certainly in favor of that too, complaints about funding are no doubt familiar to all experienced investigators. IMHO we can’t wait for more accurate, detailed model results before taking collective action at the national level, to internalize at least a low-end estimate of the marginal social cost of carbon.”

    I’ve bounced around on this idea.
    Today I think.
    We don’t need a GCM to set policy, goals, or trajectories. The technocratic dream is just that.
    I’d love to give Tim Plamer all the money he wants.
    But policy can’t and shouldn’t wait on his output.

  49. Everett F Sargent says:

    “So the regular claims that climate scientists make poor predictions because they aren’t any good at software engineering is getting towards being maximally wrong.”

    Yeah the Watties (and their ilk) do have quite a few computer science degree types. Thing is, other than having the word science in the title, a large fraction pretty much get by without much STEM training per se.

    Anyone can program, but it is the glue (e. g. STEM) you learn, that binds everything together.

    I comment all my programs with a disclaimer that the code is really messed up, which is mostly true, 🙂

  50. Chubbs says:

    A quote from the paper:

    “The radiative effects of the known increases in greenhouse gas concentrations are relatively well-known (Myhre et al.,2013), and are broadly similar in different ESMs. By contrast, the radiative forcing due to changes in anthropogenic aerosols,especially indirect effects via changes in cloud brightness and lifetime, are poorly constrained (Myhre et al., 2013).

    These uncertainties in aerosol forcing have hindered attempts to constrain TCR from the rate of warming, especially during the pre-1980 period when the burning of sulphurous coal led to increases in CO2 and increases in sulphate aerosols, that went up almost together (Andreae et al., 2005). As a result it has been difficult to distinguish, based purely on the observational record of global warming, between a model with high TCR and strong aerosol cooling, and a model with low TCR and weak aerosol cooling.

    In order to minimise the effects of uncertainties in aerosol forcing, we need periods in which aerosol radiative forcing changes relatively little compared to the change in radiative forcing due to CO2 and other well-mixed greenhouse gases. Fortunately, this applies to the decade after 1970 when total aerosol load from global SO2 and NH3 emissions were similar to values over the last decade (Stevens et al., 2017)”

    If aerosol uncertainty increases before 1980, and a good TCR estimate can be made from the period after 1970; why would you go back any further than 1970 to estimate TCR?

  51. Mal Adapted says:

    Steven Mosher:

    I’ve bounced around on this idea.
    Today I think.
    We don’t need a GCM to set policy, goals, or trajectories. The technocratic dream is just that.
    I’d love to give Tim Plamer all the money he wants.
    But policy can’t and shouldn’t wait on his output.

    You, at least, think. You’re really not a lukewarmer either.

  52. Mal Adapted says:

    Everett F. Sargent:

    Anyone can program, but it is the glue (e. g. STEM) you learn, that binds everything together.

    I comment all my programs with a disclaimer that the code is really messed up, which is mostly true,

    I arrived at my IT career via a doctoral program in Ecology and Evolution, when I discovered IT was an easier way to make a living. I learned how to write Fortran in a course I took as an undergrad. My one and only peer-reviewed publication involved simple models of butterfly mating behavior. At the beginning of my IT career, I wrote f77 code for a soil heat transfer component of a forest-succession model under, yes, climate change. Pretty much all I was able to do was encode the mathematics from a couple of key publications, and reality-check the results from basic physical principles. After giving up Biology for IT altogether, I took other structured programming courses on the way to an MS in Computer Science, and acquired multiple compiled and interpreted languages. I always tried to make my code look pretty, and document it thoroughly inline, but it was never an engineered product, nor was it ever published. That is, I wasn’t a scientist or an engineer: yet I made a pretty good living, chose my working conditions, and was able to retire a couple of years early.

    Bottom line: people who are both authentic domain experts and trained software engineers, are scarce and expensive.

  53. Mal Adapted says:

    Ben McMillan:

    Maybe the level of uncertainty is because climate is a particularly gnarly problem?

    Climate certainly is a gnarly problem, almost as gnarly as ecology and evolution, and assuredly too gnarly in the details for me. Gnarliness may account for a lot of residual uncertainty, but is it the only problem for GCMs? Can it be overcome by throwing exascale computing at it?

  54. David B. Benson says:

    Mal Adapted, as a retired computer science professor I’ll state that what you did for a living was software engineering.

  55. Mal Adapted says:

    smallbluemike:

    I think it doesn’t happen because we don’t function as a race, we function as social groups with a long history of competition over various resources.

    As a practical matter, we could function at the national level by enlisting “patriotism”, i.e. nationalism. A governing plurality of voters, not even a majority, is all it will take for the USA to make progress.

  56. Mal Adapted says:

    David D. Benson:

    Mal Adapted, as a retired computer science professor I’ll state that what you did for a living was software engineering.

    Thanks, but that’s subject to interpretation. In the mid-1990’s I learned about the Software Engineering Institute at Carnegie-Mellon University. Nothing I did would have met their most rigorous standards. I think SM is saying GCMs need to meet them to satisfy policy makers. I agree up to a point, but lukewarmers will set impossible requirements.

  57. I hope you are right, Mal. I would like to see that happen.

    My immediate reaction is I think it makes no difference if the social group is a “race” or a nationstate, the problem with competition over cooperation exists as long as we function as anything but a sentient, compassionate species that recognizes that continued existence depends on cooperation. Once a powerful group recognizes and commits to that kid of effort, other groups may follow and maybe our species could bring something new to the planetary situation. If a powerful nationstate (or two) and its/their patriots take their politics, aspirations, patriotic efforts to the global level and makes a big play to invite a cooperative global effort, then we might see real progress and change. That is asking and hoping for a lot. But, why not ask for what we really need?

    I think nations and patriotic groups are subject to the prisoner’s dilemma, the spirit of competition/demonization etc. The IPCC and UN efforts, the paris agreements etc are to a certain extent to persuade a sentient species to act cooperatively for continued existence. Those efforts may be the best we can do in this regard, time will tell if we can up our sentient species game and cooperate or if will engage in disastrous, competitive smaller group gamesmanship. Nash and game theory comes to mind. Now imagine Trump/Pompeo/Pence et al trying to absorb a different way to play the game. That is hilarious and tragic when I think about it. Who knows? Maybe it could happen. Pigs could surprise me and start flying tomorrow morning. I am ready to be surprised. Bring it on! as a recent political leader of my nation said.

  58. Ben McMillan says:

    Mal: “Can it be solved by throwing exascale at it?”
    You would expect the last 30 years of faster supercomputers to have made a big difference to narrow the error bars, if computer speed was the main problem. But I think the error bars haven’t got that much narrower.

    So unless there is some close-by threshold on computational power where GCMs suddenly all converge to each other (maybe you can throw away the parameterisation), it seems unlikely to me.

    I think ocean dynamics modelling and, as a result, decadal variability, got better recently (mostly just finer ocean grids?), but that doesn’t do much for ECS estimates.

    Think the problem is still mostly the science (all the complicated messy cloud physics etc) and not the computers. Still, exascale can and will be tried, obviously, and it will no doubt be useful.

    https://www.metoffice.gov.uk/research/approach/collaboration/spf/excalibur

  59. Mal Adapted says:

    sbm:

    I think nations and patriotic groups are subject to the prisoner’s dilemma

    Indeed, common pool resource problems may be thought of as Prisoner’s Dilemmas:

    Generalized to more than two participants (players), Prisoner’s Dilemma becomes a version of the so-called Tragedy of the Commons (Hardin, 1968).

    Game theory has broad application to evolutionary biology, too.

  60. angech says:

    My wife is giving money to the bushfire appeal because koalas.
    ABC Australia lovely documentary on a bush hospital.
    Very touching.
    Koalas live in eucalyptus forests.
    Sclerophyll forests.
    Prone to bushfires for Millenia.
    By choice??
    Sort of.
    Not really.
    But no choice.
    So they routinely go through a cycle of life and death at the stake.
    With or without human intervention.

    Some things in this world cannot be fixed by human intervention.

    Our reactions to them are shock horror pity and a desire to prevent them in future and help them now.

    Just like the people in Hurricane Katrina.

    It is not really money we are giving.
    It is just one way of trying to cope with the unfairness of life.
    Others suffer while we live.

    Is it a better world because people care?
    Definitely.

  61. John Hartz says:

    I suspect that most of you following this thread are part of the Boomer Generation. In that context, this one’s for you.

    Boomers: It’s not too late. You can be heroes in the story of climate change.

    You might not like to hear it, as many of you have long told pollsters you consider yourselves environmentalists, but collectively you have exacerbated the climate crisis more than any other generation.

    Fossil fuels were cheap as you came of age and you burned too much of them. Your lifetime carbon footprint is so high you’re forcing kids born today to emit eight times less than you just to hit a modest goal. And you’ve never taken climate change as seriously as the generations behind you.

    Boomers: You can still be heroes in the story of climate changeLaura McGann, Policy & Politics, Vox, Jan 8, 2019

    FWIW, I am of the Pre-Boomer Generation.

  62. Mal Adapted says:

    John Hartz:blockquote>FWIW, I am of the Pre-Boomer Generation.

    I am of the Boomer Generation. I know I speak for an entire generation when I say I’m between 56 and 74!

  63. David B. Benson says:

    Mal Adapted, most software engineering hasn’t been up to those rigorous standards. I am reminded of the account of a Mars orbiter which instead of orbiting plowed up the Martian ground. The problem turned out to be that the Small Forces module was written using English units and nobody informed JPL, which of course uses SI units

  64. David B. Benson says:

    However, applying IV&V to GCMs seems a ludicrous waste. There are many GCMs all solving the same problem and obtaining approximately the same answers. Putting the effort into understanding clouds and also permafrost is more to the point.

  65. Steven Mosher says:

    “You, at least, think. You’re really not a lukewarmer either.”

    the meaning of the term changed under my feet. such is the nature of language.

    I’d call myself a concernist but it’s not as catchy.

    in short, even if there is reason to panic, don’t panic. pick up the flag and carry on

  66. dikranmarsupial says:

    angech ” Some things in this world cannot be fixed by human intervention.”

    But that doesn’t mean that there aren’t problems that are made worse by human intervention that we should probably take steps to minimise our intervention. Part of the problem is that we care more about koalas than we do about people.

    Steven Mosher wrote “in short, even if there is reason to panic, don’t panic. pick up the flag and carry on”

    well, quite!

  67. Everett F Sargent says:

    angech sez …

    “Some things in this world cannot be fixed by human intervention.”

    Should be …

    Nothing in this world can be fixed by human ignorance.

  68. angech says:

    Agree with both of you

  69. dikranmarsupial says:

    Then why do you post on blogs criticising (often quite vituperatively) people who are actually trying to do something about it?

  70. angech says:

    I try not criticise people for trying to take sensible steps to reduce human caused problems.
    Here or at other blogs.
    Don’t laugh.

    I do criticise people whose efforts at actually trying to do something are done in the wrong way.
    I have consistently stated and try to stick to that position.
    I do get ( very) upset at some people who put up arguments that ( I feel) they know are wrong in the way that they are using them at other blogs.
    Trying to do something about it, as you do, involves explaining the problem perceived, coming up with possible solutions and trying to get people to implement them.

    There is also a medical imperative which is first do no harm.
    Paraphrased by Shakespeare in Hamlet “To act or not to act”
    Also in Wicked one remembers “ No good deed goes unpunished”

    Remember that I am a person with feelings too when you get aggrieved.
    I bleed in the same way when my views are belittled or challenged or people attack me vituperatively.
    Ruth Bader Ginsberg is reputed to have said that when she gets angry she tries to listen and not speak until the right time. I try but I am nowhere near her league.

    Happy to listen to you here, praise or attack your points of view if I can and be called out for any bad behaviour here. You have the runs on the board.

  71. JCH says:

    Mal: “Can it be solved by throwing exascale at it?”

    Tapir Schneider hints in one of his videos that we should ask the question in a few months, so maybe they are exascaling the clouds right now.

  72. JCH says:

    Spullin Chekka: SB Tapio.

    As for the koalas, pray more often for the stadium wave. It’s working great for the cute little bears so far.

  73. “Boomers: It’s not too late. You can be heroes in the story of climate change.”

    Boomers ( I am not one, I’m GenX) invented the modern solar panels, windmills and nuclear power plants, left the next generation the peace, wealth, and abundance of food necessary to implement either that works, and expanded the universities in the hopes the next generation would be smart enough to choose wisely.

    The most important thing Boomers can do for climate change right now is explain to younger generations that theirs are the most extraordinarily privileged in world history and they ought to use their unprecedented access to information, spare time, and wealth to actually learn how economies and energy infrastructure work if they really want to change them.

  74. Joshua says:

    angech –

    > I do criticise people whose efforts at actually trying to do something are done in the wrong way.

    Another decider.

  75. Mal Adapted says:

    angech:

    There is also a medical imperative which is first do no harm.
    Paraphrased by Shakespeare in Hamlet “To act or not to act”
    Also in Wicked one remembers “ No good deed goes unpunished”

    It is the nature of common-pool resource problems that to do nothing is to do harm. Furthermore, as prisoner’s dilemmas, commons dramas must be resolved collectively: private efforts, though they may contribute marginally to the solution, will ultimately be overwhelmed by individuals seeking private advantage. Open-ended global warming is death row, and there’s no get out of jail free card. We can only escape by cooperating. The question, therefore, isn’t “to act or not to act”, it’s “to act collectively, in the most mutually agreeable way that will cap the net cost as low as possible”, politics being the art of the possible. Responsible members of a nominally democratic society recognize that any collective action is a slippery slope. In the case of climate change, there are no win-win options: somebody’s ox will be gored! [“Block that metaphor!”] Nor does history reassure us that any collective choice we make will be optimal for everyone else. There may very well be better collective options, than to internalize some fraction of the marginal social cost of carbon in the energy market. All I know is that doing nothing is a really bad option!

    Doc:

    Remember that I am a person with feelings too when you get aggrieved.
    I bleed in the same way when my views are belittled or challenged or people attack me vituperatively.

    AFAICT you are sincere in a way that RickA, for example, is not. Yet your comments make me think you are a lukewarmer in the pejorative sense. I’ve made my opinion clear it’s immoral to abuse logic, deliberately or or otherwise, to deprecate the tragedy of AGW’s victims. I’m deeply saddened by the fate of so many koalas, but I for one place it in proportion to the growing global disaster. Some statistical proportion of Australia’s current fire season, and thus of koala deaths, is due to AGW. What proportion of global human deaths, before climate eventually stabilizes, seems preposterous to you? How many entire species driven to extinction? Why the Hell aren’t you alarmed?

    More objectively, assuming tragic statistics can somehow be converted to dollar value: it’s IMHO folly to argue that the aggregate social benefit of burning fossil carbon exceeds the aggregate social cost. I gather that’s something like a consensus view here, yet so much of what we say seems not to penetrate your thinking. I’m sorry Doc, but you can’t blame us for using emphatic language.

  76. Mal Adapted says:

    JCH, thanks.

  77. Mal Adapted says:

    jeffnsail50:

    The most important thing Boomers can do for climate change right now is explain to younger generations that theirs are the most extraordinarily privileged in world history and they ought to use their unprecedented access to information, spare time, and wealth to actually learn how economies and energy infrastructure work if they really want to change them.

    Yours is rather an exclusive message. Disclaimer: I don’t actually speak for everyone born between 1946 and 1964. Yet while I hardly discourage young folks anywhere from pursuing literacy in technical details if they have the intellectual and economic capacity, IMHO the rest of them just need to be scientifically meta-literate enough to trust the consensus of climate scientists. By the grace of information technology, that can be taught everywhere. All that’s further needed, is for it to inform their collective choices. I encourage scientifically meta-literate young people around the world to work the levers of politics on behalf of climate realism. I implore them to “Unite behind the Science“, IOW. How about you, jeffn’?

  78. Mal Adapted says:

    Anglophone youngsters, at least, need to understand this much science.

  79. dikranmarsupial says:

    “I try not criticise people for trying to take sensible steps to reduce human caused problems.”

    rubbish, I have seen your posts at WUWT.

  80. “I encourage scientifically meta-literate young people around the world to work the levers of politics on behalf of climate realism.”

    To get the politicians to do what? This is why economic literacy and a basic interest in what you really can and cannot use to power New York City is important. No change in the NYC power grid will happen as long as people are proposing to power it with unicorns at unlimited cost.
    Even when you assume universal agreement on climate science, you still have to take economics and technical feasibility into account before a single thing gets done.
    This isn’t too much to ask. Many climate campaigners in the US liken the task to mobilization for WWII. That mobilization required two things- agreement on the awfulness of the enemy and a realistic plan to do something about it. They mobilized and bought bonds to build tanks, ships and airplanes. They did not glue themselves to subway cars to create awareness.

  81. Mal Adapted says:

    jeffnsails850:

    Even when you assume universal agreement on climate science, you still have to take economics and technical feasibility into account before a single thing gets done.
    This isn’t too much to ask.

    I don’t assume universal agreement. Quoting myself, “A governing plurality of voters, not even a majority, is all it will take for the USA to make progress.” And once an effective carbon price is in place, I won’t have to take economics and technical feasibility into account except in my own household budget: I’m OK with leaving bigger investment decisions to the market. Good thing, because I don’t have time to master the predicted costs and benefits of one grid-scale carbon-neutral energy source over another.

    jeffn’:

    Many climate campaigners in the US liken the task to mobilization for WWII. That mobilization required two things- agreement on the awfulness of the enemy and a realistic plan to do something about it. They mobilized and bought bonds to build tanks, ships and airplanes. They did not glue themselves to subway cars to create awareness.

    More and more of us are agreeing on the awfulness of the enemy – don’t you pay attention to the news? The percentage of Americans who see climate change as a crisis has increased from 23% to 38% in 5 years. The problem is technological, economic and political in ascending hierarchical order. Along with a plurality of resolve, we need a cost-effective arsenal of technology to cap the net cost of warming, and every decrement in emissions helps as long as it doesn’t preclude any others.

    So mobilize. I think collective intervention to internalize some fraction of the social cost of carbon in the energy market can potentially help a lot, within a critical timeframe. But you mobilize your way and I’ll mobilize mine. While I wouldn’t glue myself to a subway car, I think it’s a clever stunt to draw media attention. Would you prefer the media ignore the looming climate crisis? Try demonstrating for that ;^)!

  82. Joshua says:

    > That mobilization required two things- agreement on the awfulness of the enemy and a realistic plan to do something about it.

    The second is a function of the first. By the standards of justification “skeptics” wish to apply to address climate change, the war effort mobilization would be deemed unrealistic.

    This is about downside risk of massive magnitude. With WWII, the high damage risks were immediate and obvious. In the case of climate change, the high damage risks are more abstract. Along a scale. Until they aren’t.

    But you should be more honest and stop playing your game about what is or isn’t “realistic.” You think it’s worth gbkinf on the future of low probability high damage risk. So be it. You’re entitled. But you haven’t, and” can’t, demonstrate that mitigation isn’t “realistic,” as that determination is a function of the will to get it done.

  83. Joshua says:

    “gbkinf” = gambling.

  84. “But you should be more honest and stop playing your game about what is or isn’t “realistic.””

    You too. In France and Germany, people who say reducing emissions is a urgent need, have set as their first order of business the closure of emissions-free power plants. And then joined with Russia to buy a new natural gas pipeline. That is not a realistic plan to reduce emissions. Neither is the Green New Deal in the US.

  85. Joshua says:

    What is “realistic” is subjective, and a function of will (which is predicated on the perception of risk).

    It’s a very basic concept. Why is it lost in you?

    Once again, absent the perception of immediate risk, the sacrifices made during the war effort would be deemed “unrealistic.” Americans in general would consider the South Koreans’ level of personal sacrifice for the sake of societal benefit post Korean War to be “unrealistic.”

    You should make a greater effort to differentiate your own opinions from fact.

  86. Joshua says:

    It’s “unrealisic” to think that millions of people would willingly march into war, sometimes in the face of near certain death, motivated by concern for future generations.

    It’s never happen.

  87. Mal Adapted says:

    jeffnsails850

    “But you should be more honest and stop playing your game about what is or isn’t “realistic.””

    You too. In France and Germany, people who say reducing emissions is a urgent need, have set as their first order of business the closure of emissions-free power plants. And then joined with Russia to buy a new natural gas pipeline. That is not a realistic plan to reduce emissions. Neither is the Green New Deal in the US.

    More strawman rhetoric. AFAIK, Joshua didn’t join with Russia to buy a new natural gas pipeline, nor did he author the GND. But never mind. What’s your realistic plan to reduce emissions? Don’t spare the details! I hope I don’t regret that ;^).

  88. Mark B says:

    No change in the NYC power grid will happen as long as people are proposing to power it with unicorns at unlimited cost.
    NYC might not be the best example. The New York State electricity grid currently is about 60% carbon-free (35% nuclear, 22% hydroelectric, 5% wind/solar). We also have have a 1.1GW pumped hydro peaker that load levels the nukes, which implies geography that plausibly supports more of the same. There’s a pretty straightforward path to expanding renewables.

  89. Ben McMillan says:

    An obvious way to think about how to reduce carbon emissions is to look around at other nations of a similar state of economic development and ask which ones have low per capita emissions, and if there are any doing much better than you, to try that as a model.

    US and Australian per capita emissions are at about 20 tonnes CO2/annum. EU and Germany at around 8. UK and France at around 6. Actually these rich countries are at about the world’s average emissions levels.

    You could also look at whether countries are doing a good job reducing their emissions recently. UK is a good model for rapid emissions reduction recently: almost all the coal is now switched off. But now that UK electricity is relatively clean, most of the emissions reduction has to come from other sectors. Pretty clearly transport is the biggest problem in the UK, and electric cars will make a big difference there.

    Note that there is not one true strategy! The electricity sector is also not the only factor.

  90. Chubbs says:

    Another coal shutdown announcement in the US. Would be easy to speed things up with some climate policy.

    :”Proposals for new renewable projects are coming “in at such a low rate” that Tri-State might be able to more quickly write off the costs of closing down the coal plants and mine, Highley added.”

    https://www.denverpost.com/2020/01/09/tri-state-coal-plants-closing/

  91. BBD says:

    Ben McMillan:

    But now that UK electricity is relatively clean, most of the emissions reduction has to come from other sectors. Pretty clearly transport is the biggest problem in the UK, and electric cars will make a big difference there.

    Not as sanguine as you about the relative cleanness of UK electricity generation nor (as previously discussed) the likelihood of deep decarbonisation in that sector, but to your point about the transport sector – this is discouraging:

    The average carbon dioxide emissions of cars sold in the UK rose for the third year in a row during 2019 as falling diesel sales and the rising popularity of SUVs dealt a blow to Britain’s hopes of reaching climate targets.

    Average CO2 emissions rose for the third year in a row, up 2.7% year on year to 127.9g of CO2 per kilometre, according to data from the car industry body. This is far above the newly introduced EU target of 95g per kilometre carmakers need to achieve over this year and next for all new cars. Cars account for just over 18% of UK emissions, according to government figures. Transport emissions as a whole account for a third of the UK total, with the sector viewed as vital contributor if the country is to achieve goals of cutting emissions to 51% of 1990 levels by 2025 and to reach net zero by 2050.

    Source: The Guardian 06/01/20.

  92. Ben McMillan says:

    Yep, the UK is not currently doing enough on transport, and cars in particular.

    That said, I’m not going to mourn the death of diesel.

    We had this discussion already, but I think there is too much emphasis on perfect energy systems, and not enough on quickly moving to something better. What matters is the area under the emissions curve, not getting to some target point.

  93. BBD says:

    I thought what mattered was total emissions.

  94. Ben McMillan says:

    Area under the emissions curve=cumulative emissions.

  95. “{What is “realistic” is subjective, and a function of will (which is predicated on the perception of risk).”
    30 years of refusing to realistically answer “the will to do what?” isn’t working.

    Mal “What’s your realistic plan to reduce emissions? Don’t spare the details! I hope I don’t regret that ;^).”
    Stop closing nuclear plants, it is your lowest priority. Focus on providing low-cost effective power generation technology that can be used in developing nations- where people are building new generation capacity right now rather than replacing sunk costs. Whatever that is will be what replaces western existing technology.
    IMO the developing world (and most of the developed world) has clearly said no to using any significant amount of renewables (other than hydro) so it’s time to be at least open to next gen nuclear, CCS and using the current gas glut as a bridge fuel. Advocates have beaten the solar/wind drum for 30 years and nobody’s marching. There are real reasons for that, Pielke, Curry, and Exxon aren’t the reasons.
    Prioritize the electrification of transportation in both the developing (a real opportunity as they don’t have the infrastructure for ICE vehicles) and developed nations. Accept that this means more electricity production not less (including per capita) and that cost and reliability matter.
    Take a new approach to COP and the IPCC- the next Assessment Report and meeting should be a scientific analysis of various options carbon free energy with attendant summaries for policy makers. It should have one sentence on ECS, that’s an academic debate that you already know is irrelevant to decision makers without viable options for action. The political left will not like the results of that technology analysis, but this never should have been a left/right thing to begin with. Correct that mistake.

  96. Joshua says:

    > 30 years of refusing to realistically answer “the will to do what?” isn’t working.

    Your repeated responses witihout engaging with what I write are banal and creative at the same time.

  97. BBD says:

    I think there is too much emphasis on perfect energy systems, and not enough on quickly moving to something better.

    […]

    Area under the emissions curve=cumulative emissions.

    Ben, if we design a system which isn’t going to decarbonise to zero, then we will fail.

  98. Joshua says:

    Beautiful irony:

    > The political left will not like the results of that technology analysis, but this never should have been a left/right thing to begin with. Correct that mistake.

    It shouldn’t be a left/right thing to begin with, and it’s “the left’s” fault.

    A variant on “If only those poopyheads would stop calling us poopyheads everything would be fine. “

  99. Joshua says:

    BBD –

    What about the argument that we should work on electrifying energy usage on a massive scale, under the logic that eventually there will be an electric pathway to zero, and the will to get there?

  100. BBD says:

    What about the argument that we should work on electrifying energy usage on a massive scale, under the logic that eventually there will be an electric pathway to zero, and the will to get there?

    The further down the ‘electrify everything’ route we go, the greater the demand for electricity and the more disruptive the consequences of supply shortfall. Since avoiding supply shortfall requires a substantial gas backup to W&S, the more firmly entrenched we get in infrastructure that cannot get to zero emissions.

    It’s a bugger.

  101. BBD says:

    I should add that decarbonising the electricity supply is – supposedly – the easy part. Decarbonising agriculture, construction, aspects of manufacturing and the shipping and aviation sectors of transport are going to be much harder. To tie this back to the topic, if sensitivity is higher than previously estimated then the consequences of failure to decarbonise rapidly and completely will be worse than estimated. So there may be even less room for bodging the design of decarbonisation pathways than we thought.

  102. Ben McMillan says:

    It is in fact perfectly possible for emissions to be always positive, but cumulative emissions to stay below a threshold forever.

    So if you reduce emissions by 5% a year (compounded), you never get to zero, but you only ever emit a finite quantity (20 years at current emissions rate). And it is cumulative emissions that matter.

    So you do need increasingly deep decarbonisation, but don’t need to go to exactly zero in, say, 2050 or 2070.

    I think “we are at 20% of 2020 emissions levels in 2050, but it will take another 30 years to get to exactly zero” would be a nice problem to have. The first 80% of emissions reductions are roughly four times more important.

    Strategically, having a pathway to meeting some relatively strict medium term targets seems like the most sensible way to get to the long term targets. It is nice to have a plan for an energy utopia in 2070, but it probably won’t turn out that way anyway. If it means we can avoid frying the earth, I’m OK with a plan that involves having some fossil infrastructure sitting around for a while.

  103. Nice analysis and overview on emissions, Ben! Of course, just cutting emissions does not assure us that accumulation in that atmosphere will drop in a linked fashion. We have potentially large problems with accumulation that could present as new natural sources of GHG come to life and as traditional natural carbon sinks degrade/change on a warmed planet. We are literally playing with fire as we burn fossil fuels today.

    I hear the good news on falling emissions on a regular basis. I can’t get very excited about reports of and plans for reduced emissions as I watch CO2 continue to rise in the atmosphere at an annual rate of 2.5 ppm or more. Carbon emission appears to be very easy for humans, it’s proving to be quite difficult for our species to convert itself to a carbon sink.

  104. BBD says:

    It is in fact perfectly possible for emissions to be always positive, but cumulative emissions to stay below a threshold forever.

    Can you unpack this a bit for me Ben? As SBM mentions, carbon cycle feedbacks and sink attenuation would seem to be potential issues here, but possibly I haven’t understood what you are saying.

  105. “Beautiful irony:”

    Nope. The last two decades of this “debate” has featured some variation of “wind and solar only” (witness the half dozen “100% Renewables” plans that will never be built), along with “economic transition” (witness Rep. Alexandria Cortes’ campaign manager who was surprised that people thought the Green New Deal was climate plan- they wrote it as an economic plan.).
    Those were political policy choices, not technical, and they were driven by partisanship. The people who wrote 100% Renewables plans will be saddened by a genuine technical analysis and the parties that campaigned on shuttering nuke plants will be angry. You guys made sure every media outlet made it crystal clear that only right-wingers opposed 100% Renewables and closing nukes. That was always a mistake.

  106. Joshua says:

    BBD –

    > Since avoiding supply shortfall requires a substantial gas backup to W&S,..

    It seems worth it to me to bet that is not a permanent state.

    > Decarbonising agriculture, construction, aspects of manufacturing and the shipping and aviation sectors of transport are going to be much harder.

    No doubt. But I’m increasing starting to think that within the frame of managing relative levels of risk, and political realities, we should be pushing hard on electrifying everything as the first order priority – taking on the inherent risks associated with the obstacles which that way lie.

  107. Joshua says:

    > . The last two decades of this “debate” has featured some variation of “wind and solar only”….

    The last two decades of this “debate” has featured some variation of “its a Chinese hoax perpetrated by one-world government fanatics and scientists lining their pockets with indifference to starving children in Africa and, of course, Lysenko.”

    And unfortunately, you can’t seem to ever get off your broken record if a political agenda – even to the point of writing a single response that is actually on topic with the comment you’re responding to.

  108. verytallguy says:

    “You guys made sure every media outlet made it crystal clear that only right-wingers opposed 100% Renewables and closing nukes.”

    Complete cobblers. Here from the very head of the snake:

    https://www.theguardian.com/commentisfree/2011/mar/21/pro-nuclear-japan-fukushima

    And that’s without even starting on the “you guys” idiocy.

    Need a better class of sceptic.

  109. Ben McMillan says:

    Well, I am basically just thinking of Zeno’s paradox: go forwards 1/2 a metre, then 1/4 a metre, then 1/8 a metre, and so on. You never quite get to the meter line.

    So ignoring complications like feedbacks/sinks, it is possible to emit 100 tonnes per person in the 2020s, 50 tonnes per person in the 2030s, 25 in the 2040s: the total is never quite going to add up to 200 tonnes.

    I think that the point I’m trying to make is that “we have to get to net-zero by 2050” is fine as an aspiration, but the goal is really preventing excessive climate change, which is about cumulative emissions. So there is a tradeoff between how fast you reduce emissions now and how deep you need to reduce them later. And perfection in 2050 would be great, but not the actual aim.

    Even ‘deep decarbonisation’ is not exactly zero: it is about 20x better than current electricity supply.

  110. Joshua says:

    Jeff –

    Everyone here knows that you don’t like lefties, and want to blame them for everything you don’t like related in any way to climate change, and perhaps anything else for that matter.

    From a communication standpoint, it really isn’t necessary for you to keep repeating the same thing over an over. We know what you think.

    The next time you’re about to put up a comment, ask yourself a question about what is really motivating your post. If the answer is that you want to communicate your antipathy about lefties, to lefties, ask yourself it its really worth it to post yet another comment in that vein yet again..

    My guess is that it feels like you gain some measure of satisfaction from expressing your antipathy. My guess is that at some level, it makes you feel good to express your antipathy towards people you identify as an “opponent.”. Maybe you think that you’re making an “other” feel bad, or annoyed, or attacked – and in a way that makes you feel good.

    You would not be remotely unusual in feeling that way. We can see easily see evidence of the ubiquity of that behavior pattern – particularly online. But I would suggest that it’s an empty sort of satisfaction * which may feel good in the moment but leads to no long term benefit. That’s why you repeat the same behaviors over and over – they don’t substantiate any kind of longer term change or growth.

    Shoot higher. Don’t sell yourself short if you doubt that you’re capable of a more substantive form of interaction.

  111. Joshua says:

    What Ben says makes sense to me.

  112. Mal Adapted says:

    jeffnsails850:

    Stop closing nuclear plants, it is your lowest priority.

    Stop putting words in my fingers! It’s dishonest, and it ensures this conversation can never move forward. I’m just going to keep calling out your strawman rhetoric. Is preventing a single nuclear plant from closing your highest priority? It isn’t my lowest, but it’s not my highest, either: quickly capping the net cost of AGW, by every politically possible means, is! I’ve made it clear I’m fine with many existing nuclear plants contributing carbon-neutral energy throughout their useful lifetimes. I’m not on the “side” of uninformed radiophobia in or out of the US Democratic Party, for cryin’ out loud!

  113. BBD’s formula is a right, but already a bit backwards. His concern is the use of fossil fuels as a secondary source with W&S as primary. Germany – where nobody thinks climate change is a hoax – already approved Volkswagen’s plan to replace their power plant with natural gas- so the real status is that gas is the primary energy source, W&S the secondary.
    This is because of economics and technical reality. They cannot power the factory with W&S alone. They need a half-billion-Euro natural gas plant with or without W&S. Nobody can spend that much money without using it, and for economic reasons they need to buy the gas on contracts rather than on the spot market at unpredictable times. Some wind and solar can nibble at the margins of daily gas use, but won’t be primary.
    The only objection the right has to the plan is the source of the gas, The left opposes the entire project and wants the factory powered by W&S. And that won’t happen.
    It’s further complicated. Volkswagen, like every other auto maker in Europe, has factories in Asia and North and South America. Order them to spend the money on solar panels and transition to a new economic structure in Germany and the only result is more coal burnt outside of Germany.
    IMO what irritates Joshua is that he thinks I’m gloating that the right “won” cases like this. I’m not, it’s just reality. Economically, I couldn’t care less if Volkswagen used its cash for a dam, wood, nukes, or gas. All would do the trick. Environmentally I’m glad they aren’t using coal. Gas will cut emissions, they could have cut more but nobody seems particularly concerned that they didn’t. If they were, they’d read up on what it takes to run a factory. The “hoax” myth (yes, it’s a myth) endures because every day and every dire warning makes it less excusable to fail to educate yourself on economics and technology.
    I don’t agree with them because I’ve been reading folks like you for a long time, but rational people can conclude that, at this point, this ignorance is intentional and political. FWIW, I just think it’s due to the fact that it’s really really hard to say you’re wrong, especially when your political life is tied up in it. I was wrong- I thought nukes were the answer, turns out it’s gas. In 2050 we’ll revive the W&S/Nukes debate.

  114. Mal Adapted says:

    Joshua:

    What Ben says makes sense to me.

    I find that about most of his comments.

  115. BBD says:

    It seems worth it to me to bet that is not a permanent state.

    Only if PHES displaces gas, which as Ben quite rightly points out isn’t likely to happen given that gas is easy and cheap whereas PHES will be expensive, slow to build out and controversially damaging to the environment (typically upland wilderness in the UK). But unless we do that, it’s extremely difficult to see how full decarbonisation of the electricity supply will be possible.

    No doubt. But I’m increasing starting to think that within the frame of managing relative levels of risk, and political realities, we should be pushing hard on electrifying everything as the first order priority – taking on the inherent risks associated with the obstacles which that way lie.

    Electrify everything is the only way to go, of course. But hopefully you can see why it brings its own set of issues in to play unless the decision is made to plan to displace gas over the next several decades. And there is no indication that this will happen because of the economic realities currently constraining decision making.

    Well, I am basically just thinking of Zeno’s paradox: go forwards 1/2 a metre, then 1/4 a metre, then 1/8 a metre, and so on. You never quite get to the meter line.

    So ignoring complications like feedbacks/sinks, it is possible to emit 100 tonnes per person in the 2020s, 50 tonnes per person in the 2030s, 25 in the 2040s: the total is never quite going to add up to 200 tonnes.

    Okay, thanks, that’s what I thought you meant, including the ignoring feebacks and sinks.

  116. mrkenfabian says:

    BBD – I see a lot of potential for gas plant to transition to Hydrogen and continue to function as backup to Wind and Solar using H2 produced by Wind and Solar. A lot of existing gas generators are capable of high H2 content fuel, they sit right where energy transmission converges and could produce and store Hydrogen on site. Hydrogen would not need to be compressed to high densities (with associated costs) required for transport or transportable fuel.

    The scale of the problem is huge – but whatever we do collectively cannot be anything other than at unprecedented scale. Including – and highly likely – mess things up. But I am not prepared to give up on optimism; the politics is at a tipping point that can see climate science denial lose all it’s mojo. Just removing the deliberate impeding and undermining of serious climate policy will make what we do more effective.

  117. I watch coal trains roll through town about a mile from my place and I know the coal trains are headed to the local “steam” plant. “We” stopped mining poor quality coal here a few years ago and upgraded the setup to use better coal delivered by rail. I guess I will assume that is a real improvement, but watching the coal trains roll by, knowing that we are all breathing coal dust and getting mercury dropping out of the exhaust, makes me wish that we would take the next step and stop burning coal and use natural gas instead.

    We, in this case, is the power company in the adjoining town that operates the steam plant. The State (WA) is leaning on the operator to give up the coal and I think that will happen eventually, but I wonder why it doesn’t happen sooner rather than later.

    Isn’t it pretty straightforward to convert a coal plant to a natural gas fired operation? It’s all about the economics of conversion and coincidentally, the tragedy of the commons.

    btw, lots of “good” local jobs were lost when the steam plant stopped operating the mine adjacent to the power plant. I think more jobs will be lost when the plant moves away from coal. How exactly do these decisions get made? Pretty straight forward economics that play out in a municipal or region level. Not much global thinking in play as long as there is no carbon tax.

  118. David B. Benson says:

    A new air conditioning principle:
    http://bravenewclimate.proboards.com/thread/697/power-world?page=4#post-6169

    Consumes half the power.

  119. Ben McMillan says:

    I agree that getting to exactly 100% renewables is hard, in the sense that current approaches require building pumped-hydro energy storage with several days of storage of average demand. You end up with something like one of Jacobson’s plans, which are physically possible, but look pretty ambitious/expensive.

    But if you are prepared to compromise a bit, a system with 90% wind and solar, and 5% of energy from conventional hydro, and 5% from fossil backup, then things look quite a lot easier. That is not perfect, but good enough for ‘deep decarbonisation’. You need quite a lot of fossil backup plant, but it runs at very low capacity factor.

    I’m thinking of the data from:
    ‘Geophysical constraints on the reliability of solar and wind power in the United States’
    https://escholarship.org/uc/item/96315051
    Which suggests, given a US-wide grid, 90% wind and solar is possible (average power is 100%, but 10% is curtailed) with 12 hours of storage.

    Even though it requires more energy, handling intermittency actually gets easier if you need to turn electricity into liquid/gas fuels to electrify shipping/aviation: the power-to-X plants can run only when there is excess power.

    But from a practical point of view, the main question is what to do right now. And I think the answer is to build the things that look like they will be required under essentially any strategy. That is, lots of zero-carbon generation. Also, getting started properly on electrifying transport and heating. And efficiency.

  120. Steven Mosher says:

    “A new air conditioning principle:
    http://bravenewclimate.proboards.com/thread/697/power-world?page=4#post-6169

    Consumes half the power.”

    scratches head.

  121. David B. Benson says:

    Steven Mosher, what is the problem?

  122. Steven Mosher says:

    air conditioners always confuse me

  123. verytallguy says:

    Steven,

    Not new technology, though maybe domestic application is. Similar systems are routinely used industrially where waste heat eg CHP is available.

    Some background

    https://en.m.wikipedia.org/wiki/Adsorption_refrigeration

    https://www.slideshare.net/mobile/piyushpatil12/adsorption-refrigeration-system

  124. Mal Adapted says:

    A news item about yet another new cooling principle, reported in Nature: The super-cool materials that send heat to space.

    These materials might not only save on electricity bills, say enthusiasts, but also reduce a surge in demand for power-hungry refrigeration and air conditioning as the world warms. “My belief is that in four to five years, daytime radiative cooling systems will be the number one technology for buildings,” says Mattheos Santamouris at the University of New South Wales in Sydney, Australia, who himself is working to improve such materials. “It is the air conditioner of the future.”

    Sounds promising, with a “but”:

    Dreams of using the super-cool materials for geoengineering to mitigate global warming seem further off, and unlikely from a practical perspective. Last September, Munday used “back-of-the-envelope calculations” to suggest that current rising temperatures could be balanced by covering 1–2% of Earth’s surface with existing materials that generate around 100 Wm–2 of cooling power in the daytime11. But because solar panels still don’t reach that level of cover after decades of development, it seems impossible that this nascent technology could do so in time to be useful, says Mark Lawrence, a climate scientist at the Institute for Advanced Sustainability Studies in Potsdam, Germany. As with any geoengineering proposal, Munday acknowledges the possible unintended consequences of disturbing precipitation patterns and local climates — which Ürge-Vorsatz agrees are likely to be a problem.

    Has everybody seen the Sorcerer’s Apprentice sequence from Disney’s Fantasia (1940)? Humanity is like Mickey Mouse, only there’s no sorcerer to save us.

  125. BBD says:

    BBD – I see a lot of potential for gas plant to transition to Hydrogen and continue to function as backup to Wind and Solar using H2 produced by Wind and Solar.

    Yes, I live in hope that this might be the elegant fix that gets around the storage / intermittency issue without a natural gas component we can’t get rid of. A rare but bright ray of something to be optimistic about 🙂

    Even though it requires more energy, handling intermittency actually gets easier if you need to turn electricity into liquid/gas fuels to electrify shipping/aviation: the power-to-X plants can run only when there is excess power.

    But from a practical point of view, the main question is what to do right now. And I think the answer is to build the things that look like they will be required under essentially any strategy. That is, lots of zero-carbon generation. Also, getting started properly on electrifying transport and heating. And efficiency.

    Agreed (as per KenF) and yes, we need to get on and build out capacity. Rather a lot faster than we are doing. I want to see the Keeling Curve get the droops during my lifetime.

  126. I want to see the Keeling Curve get the droops during my lifetime.

    I get an uneasy/ambivalent feeling when people indicate that they are looking for signs of hope/progress in “The Keeling Curve.” And many appear to.

    Think about it. If we manage to cut our CO₂ emissions back to where they were in 1960 (about a 65% cut from 2019), the Keeling Curve would still be be rising at the slope it had in 1960 (assuming no change in the “airborne fraction” (A. F.)).

    Now, I know, if we apply some statistical tests and trendlines, we’ll “see”/detect progress, but I sense many people are expecting something much more visually dramatic/encouraging to their eye. That is one of the particular appeals of the visualization – it is so simple and unequivocal to understand at a simple glance.

    Meanwhile, little old Keeling Curve just going to be keeping on keeping on being the familiar Keeling Curve… for a long time.

    If we were to begin cutting emissions this year sufficient to halve emissions by 2030, the change of slope or progression of the Keeling would be almost imperceptible. We would be emitting at about the same level as the mid-1970’s, and with a similar rises in the Keeling Curve as in that era.

  127. And it’s off-topic for the thread, but since I am on this point…

    I sometimes wonder what the psychologists and messaging gurus have to advise on “setting expectations.” Because it seems to me that we are a species – or at very least a culture – that expects near-term gratification and results in return for effort/cost/etc.

    And climate is anything but that.

    Look at the vertical lines reflecting global temperature in the plot below, for the 2020’s, ’30s, into the ’40s. There is scarcely a perceptible difference in the colour (temperature) from SSP3-7.0 to SSP1-2.6. Yet the effort and cost mitigation between the two is immense.

    We’re not used to this.

    We are going to be asking ourselves to analogously go on the most strict exercise and diet regime ever conceived, and celebrate/remain committed as we continue to rapidly gain weight.

    I know one of the reasons that ATTP keeps reinforcing the point that there is little further warming commitment after emissions entirely cease is to somewhat quell the “but inertia in the system”/hopelessness brigade. And some of the “Green New Deal” aspects – “ponies for everyone!” – also aims to provide near-term gratification/payoffs. But I actually think we’re going to need to convey to the public that observable physical payoffs are going to be grudging.

  128. https://www.theguardian.com/environment/2016/mar/10/co2-levels-make-largest-recorded-annual-leap-noaa-data-shows#img-2

    the keeling curve image changes quite a bit depending on the time frame that is included. The problem that can be disguised with looking at shorter chunks of time in the Keeling Curve is that the rate of growth of CO2 in the atmosphere has been accelerating. The Keeling Curve does not just keep on keeping on, it shows the rate of growth. Anyone who does not understand the inherent problem should get out and play in the next big snowfall. Roll a snowball and see how long you can keep on keeping on before you encounter problems.

    I dream of seeing the Keeling Curve get the droops as BBD put it. Just to see the rate of growth stop accelerating would be a wonderful thing.

    “The rate of growth in carbon dioxide concentrations in the atmosphere has accelerated since the beginnings of the Keeling Curve. The rate has gone from about 0.75 parts per million (ppm)/yr in 1959 to about 2.25ppm/yr today.” (from 2015)

    https://scripps.ucsd.edu/programs/keelingcurve/2015/02/12/is-the-rate-of-co2-growth-slowing-or-speeding-up/

    I think the rate of growth is higher than 2.25ppm/yr now, but if it is not, or if/when we change the way that CO2 is accumulating in the atmosphere, we should see the Keeling Curve start to look more like a straight line, then someday, it might look like a flat line, then even a falling line. The upward curve in the Keeling Curve is the problem.

    I might have some of that wrong, but I think it’s generally fairly accurate. Folks will let me know, I suppose.

    Keep on keeping on,

    Mike

  129. “I know one of the reasons that ATTP keeps reinforcing the point that there is little further warming commitment after emissions entirely cease is to somewhat quell the “but inertia in the system”/hopelessness brigade. And some of the “Green New Deal” aspects – “ponies for everyone!” ”

    Speaking of ponies for everyone! That is exactly the thought that comes to mind when anyone talks about what will happen when/after emissions entirely cease. Put a target date on when emissions entirely cease and then work backwards from there to develop a plan to hit the target date. Show your work.

    Absent some serious planning, the discussion about what happens when emissions hit zero is pie in the skies, ponies for everyone rhetoric imho. Let’s revisit that discussion when the the annual growth rate of emissions drops to something below 1 ppm/yr or even 1.5 ppm/yr At that point, I would actually be interested in knowing more about what can be expected when we hit net zero. Gonna get trampled by a herd of spherical cows, if I am not careful.

  130. Let’s say the current annual increase in atmospheric CO₂ is 2.5 ppm.
    And let’s say (A) emissions stay flat for the next decade or (B) we halve emissions by 2030.
    Assuming the airborne fraction stays constant, for (A), the atmospheric CO₂ increase is 10 * 2.5 = 25 ppm. And for (B) it’s roughly 10 * (2.5 + 1.25)/2 = 19 ppm.
    So, we would end the decade between 436 and 430 ppm.
    Now, you may be able to discern that 1% difference in the Keeling Curve during the decade as you look at the curve, but I doubt that is what people are generally expecting to “see.”
    And I am not guessing here. We know people get this relationship widely wrong. We ask them to plot concentrations given an emissions scenario and most are wildly wrong.

  131. I think it is true that a lot of people get the keeling curve wrong and might have trouble plotting it accurately, but I think BBD is not one of those people. When BBD says, oooh look, the Keeling Curve has got the droops, I am going to take a look. The early indications of a change in the curve will be buried in noise, the signal might overcome noise and be seen on a ten year time frame, maybe less, but not on an annual or biannaul number.

  132. BBD says:

    Perhaps ‘the droops’ was humour at the expense of clarity. ‘Reduction in the rate of growth from exponential to linear or below’ is a bit of a mouthful though 🙂

  133. I have no doubt that many (most?) people who have studied the dilemma for “get it”, but I have little doubt that most people don’t.

    “What the…??? Why is the Keeling Curve still going up?”-bewilderment seems worthy of a headline in the New York Times in 2017.

    Now, that article was written by an excellent, experienced climate journalist, and it does look at some issues that could ultimately lead to changes in the airborne fraction. But there also is (was) no “conundrum” about having emissions stop rising and simultaneously having the Keeling Curve rise at record rates. And this is never discussed in the article.

    Just saying…

  134. Willard says:

    > here also is (was) no “conundrum” about having emissions stop rising and simultaneously having the Keeling Curve rise at record rates

    There is a similar problem with Da Paws:

    https://andthentheresphysics.wordpress.com/2019/02/17/only-connect/

    I surmise that stocks and flows are as hard to master as Bayes’ theorem.

  135. Ben McMillan says:

    The derivative (smoothed over 5 years so seasons are removed) of the CO2 curve is actually not too noisy:
    http://www.woodfortrees.org/plot/esrl-co2/mean:60/derivative
    (actually this is just proportional to the difference between the value and the one 5 years previous)

    As long as there aren’t any major volcanic eruptions (I think the dip after 1990 was Pinatubo), an emissions drop by a factor of two should be easily visible in the Keeling curve within 5 years. And we clearly aren’t going to drop emissions that fast.

    I guess you could have an actual celebration once that difference drops to half its current value. Bit of a downer though: yay, pollution is getting worse significantly less rapidly than before.

  136. Chubbs says:

    Good illustration above of the drawbacks of gradual, slow, emission-reduction pathways. Now consider the improving learning-curve economics of non-fossil alternatives like wind and solar. Argues for a rapid and not a gradual transition from fossil fuels.

  137. Pingback: A couple of highlights | …and Then There's Physics

  138. Pingback: Can climate sensitivity be really high? | …and Then There's Physics

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