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How good have climate models been at truly predicting the future?

A new paper from Hausfather and colleagues (incl. me) has just been published with the most comprehensive assessment of climate model projections since the 1970s. Bottom line? Once you correct for small errors in the projected forcings, they did remarkably well.

Climate models are a core part of our understanding of our future climate. They also have been frequently attacked by those dismissive of climate change, who argue that since climate models are inevitably approximations they have no predictive power, or indeed, that they aren’t even scientific.

In an upcoming paper in Geophysical Research Letters, Zeke Hausfather, Henri Drake, Tristan Abbott and I took a look at how well climate models have actually been able to accurately project warming in the years after they were published. This is an extension of the comparisons we have been making on RealClimate for many years, but with a broader scope and a deeper analysis. We gathered all the climate models published between 1970 and the mid-2000s that gave projections of both future warming and future concentrations of CO2 and other climate forcings – from Manabe (1970) and Mitchell (1970) through to CMIP3 in IPCC 2007.

We found that climate models – even those published back in the 1970s – did remarkably well, with 14 out of the 17 projections statistically indistinguishable from what actually occurred.

We evaluated these models both on how well modeled warming compared with observed warming after models were published, and how well the relationship between warming and CO2 (and other climate forcings) in models compares to observations (the implied transient climate response) (see Figure). The second approach is important because even if an old model had gotten all the physics right, the future projected warming would be off if they assumed we would have 450 ppm CO2 in 2020 (which some did!). Future emissions depend on human societal behavior, not physical systems, and we can usefully distinguish evaluation of climate models physics from paths of future concentrations.

Figure 2 from Hausfather et al (2019) showing the comparisons between model predictions and observations for a) the temperature trends (above) and b) the implied Transient Climate Response (TCR) which is the trend divided by the forcing and scaled to an equivalent 2xCO2 forcing.

However, it is not totally obvious how one should correct for the forcing assumptions because of subtle issues related to the different efficacy of different forcings and, of course, the remaining uncertainty in the real value of the actual forcings (driven predominantly by the aerosol component). For forcing projections that were close to linear, this didn’t make that much difference, but for scenarios that weren’t (notably scenario C in Hansen et al (1988)), the correction does not work well.

There are a few other results that stand out, notably the (infamous?) low sensitivity result in Rasool and Schneider (1971), which was mainly due to a lack of stratospheric adjustment and water vapor short wave absorption in their formulation. This was noted by Schneider (1975) and the calculation redone by Schneider and Thompson (1981) which turned out to be far more accurate. On the other hand, only Mitchell (1970) appears to have substantially overestimated the TCR – even while he predicted the temperature rise quite accurately (due to a compensation between a too large sensitivity and an underestimate of the forcings). [Amusing aside, both Manabe’s and Mitchell’s 1970 projections appeared in a special volume on the Global Effects of Environmental Pollution, reporting on an 1968 AAAS workshop and edited by (the now-notorious) S. Fred Singer before he went off the deep end].

It’s worth noting that this comparison includes two kinds of climate model – those published prior to 1988 which are energy balance models of varying complexity, and those published afterwards which are true GCMs and include atmospheric (and eventually, ocean) dynamics. Of the early models, the work of Sawyer (1972) stands out as being the most accurate in terms of both temperature trends and forcings, though this must be considered somewhat fortuitous.

The fact that both classes of climate model did so well in projecting future warming should increase our confidence that current climate models are getting things right for mostly the right reasons. While there are still real uncertainties in future warming associated with climate sensitivity, we can confidently state that the rate of surface warming we are experiencing today is pretty much what past climate models projected it would be.

Gosh, maybe we know something about climate after all!

Note: all the data and code for this study are available here.

References

  1. Z. Hausfather, H.F. Drake, T. Abbott, and G.A. Schmidt, "Evaluating the performance of past climate model projections", Geophysical Research Letters, 2019. http://dx.doi.org/10.1029/2019GL085378
  2. S.I. Rasool, and S.H. Schneider, "Atmospheric Carbon Dioxide and Aerosols: Effects of Large Increases on Global Climate", Science, vol. 173, pp. 138-141, 1971. http://dx.doi.org/10.1126/science.173.3992.138
  3. S.H. Schneider, "On the Carbon Dioxide–Climate Confusion", Journal of the Atmospheric Sciences, vol. 32, pp. 2060-2066, 1975. http://dx.doi.org/10.1175/1520-0469(1975)032<2060:OTCDC>2.0.CO;2
  4. S.H. Schneider, and S.L. Thompson, "Atmospheric CO2and climate: Importance of the transient response", Journal of Geophysical Research, vol. 86, pp. 3135, 1981. http://dx.doi.org/10.1029/JC086iC04p03135
  5. "Global Effects of Environmental Pollution", 1970. http://dx.doi.org/10.1007/978-94-010-3290-2
  6. J.S. SAWYER, "Man-made Carbon Dioxide and the “Greenhouse” Effect", Nature, vol. 239, pp. 23-26, 1972. http://dx.doi.org/10.1038/239023a0

197 Responses to “How good have climate models been at truly predicting the future?”

  1. 151

    Dan H. said:

    “Their scientific work regarding climate change should stand on its own.”

    This is repeated so often to the point of cliche but as Maya Angelou said: “When someone shows you who they are, believe them the first time.”

    Then we have the full-speed-ahead gospel according to E-P:

    “We have a serious game-changer in the pipeline. NuScale is going to be highly competitive if it can be built using electron-beam welding; 6-inch steel can be welded at at least 50 mm/min in a single pass, so a full-circumference weld on a 3-meter reactor vessel will only take about 3 hours. Production of 2 units/day (welding 2 end caps and 2 flanges per unit) from a single welder would appear feasible, running 3 shifts.”

    Wouldn’t testing of safety-critical products swamp out any time-savings during construction? Have one common-mode failure on a mass-produced product and that’s a chain-reaction disaster ready to happen.

    Presaging E-P saying this:

    “Rapid simplification won’t fix matters; it will actually guarantee that things continue to get worse. “

    What to make of “worse” in context? Well, when people tend to go with embracing less via a simplified lifestyle (as nigelj wrote), then the probability of massive failures tend to lessen as well.

    Then E-P said this:

    ” We’re not going to efficiency our way out of this problem; quite a bit more is necessary.”

    Jevon’s Paradox is obviously reduced with lifestyle changes, which I think makes sense in the context of Al Bundy’s statement “If efficiency doubles then by definition the amount of fuel burned for a task halves”

    What do others think of this kind of sloganeering? There really aren’t any easy answers to human progress and growth in a resource-constrained environment, and especially when possibly half the population follows a doctrine of dominionism.

    Al Bundy said:

    “And your discounting of E-P is an error. He knows his stuff. His “Please hate me” attitude is a disjoint issue.”

    I wouldn’t doubt it. Yet, a circular firing squad is also not optimal.

  2. 152

    David Young said:

    “One would note that Obama was able to accomplish virtually nothing on mitigation. The fracking industry gets credit for most of what little was accomplished. That process has continued under Trump.”

    This is an important point to debunk. The fracking industry (especially oil fracking in NoDak & Texas) benefited from the low-interest loans that the Obama administration introduced after the deep market recession of 2008. Obama was trying to jump-start the economy via investments in the alternative energy sector … and that the fracking industry also latched on to. Alas, although the flow of fracked oil did provide a boost to the economy, it also hasn’t done any good in the long run, as the industry is still in debt from the high-cost and low-return per well (and short lifetime of a well) characteristic of oil fracking. Moreover, the production of fracked oil is predicted to peak in the next several years.

    The insanity under Trump is that his administration claims that because of fracked oil that the USA is now a NET exporter of crude oil. Not surprisingly, this is a huge lie. Mathematically it is impossible for the USA which extracts just over 10 million barrels per day from oil reservoirs, while actually burning 20 million barrels per day to be a net exporter. For example, if the USA exported all the 10 million barrels it produces daily, it would need to import 20 million barrels per day to power the economy. So that “net exporting” claim is just nuts, yet watch how David Young will try to twist the facts if he decides to respond.

  3. 153
    Dennis N Horne says:

    The problem with Spencer’s judgement on climate science or evolution is not that Spencer is religious, the problem is only fools and cranks accept or value it.

    Unless one is an expert and able to publish science to the contrary in peer-reviewed journals of some note, any rational person, well-informed or otherwise, must accept the IPCC synthesis reports as our best view of reality, at least as a starting point.

    If people like Lindzen, Curry, Spencer, Christy … were right, they’d have received Nobel Prizes in physics, chemistry, physiology or medicine, peace, and economics — for the most important work in history.

  4. 154

    DY 140: Barton’s comments add nothing of scientific value and are wrong factually.

    BPL: Prove it. Show your work.

  5. 155

    DY, #142–

    Advocating against strong mitigation measures is a position that while unpopular with alarmists, does not imply ”denial” of any science. Policy is a matter of values and priorities, not science as Bertrand Russell convincingly argued.

    First, it is certainly true that “policy as a matter of values and priorites.” (I’ve had occasion here to point out the same thing.) But that does not mean that policy is thereby rendered infinitely malleable or arbitrary. There is such a thing as bad policy, and given that survival is a near-universally-acknowledged ‘good’, there is abundant evidence that “advocating against strong mitigation measures” may just be the worst of all possible policies.

    But, secondly, that is not what, for instance, Spencer does. He argues against the *need* for strong mitigation policy, claiming that warming will be minimal and its effects modest at best (or rather, worst). As I remarked previously, in doing so he is “in defiance a *whole* lot of evidence.” He is in that respect a textbook “lukewarmer.”

    One would note that Obama was able to accomplish virtually nothing on mitigation. The fracking industry gets credit for most of what little was accomplished.

    Obama did quite a bit more than nothing, nurturing the explosion of renewable energy which you apparently don’t wish to acknowledge, and implementing reforms such as the Clean Power Plan and the mileage standards, which are significant enough that the Trump Administration has been at great pains to undo them (a project still incomplete, by the way.) I suppose said undoing is the best argument that Obama “accomplished nothing”.

    But the “political smears” that were responsible for that were the ones emanating from the Koch- and Mercer-funded ecosystem of anti-science which put the Republican congressional majority in thrall to denial not only of Spencer’s kind, but of the crudest kind that denies the science completely.

    Natural gas is a logical first mitigation step albeit one that does nothing to feed the virtue signaling activist groups deep ideological delusions.

    There’s been mounting evidence that this is not true: that when lifecycle emissions are fully accounted for, natgas offers little mitigative effect. So if it were ever a “logical first mitigation step”, the time for that step is now past–particularly since wind and solar are now comparable or cheaper in terms of LCOE.

    I’d be quite curious to know what you think the “deep delusions” consist of. So far, you’ve failed to identify them.

  6. 156
    Dan H. says:

    #141

    You have listed several areas where the models have differed from the data. Tropospheric has been observed to be much lower than models have predicted, although the sign is in the same direction. Most research shows cloud feedback to be negative, not positive, unless you are claiming that cloud cover has been decreasing. That the models have not been more accurate is not a failing of the theory, rather just that the models are not accurately determining the outcome. They just need to be refined, that is all.

  7. 157
    David Young says:

    Another statement by Palmer and Stevens summarizes perfectly the cherry picking at the heart of the cartoon character’s deception.

    “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.”

    The papers cited by the cartoon character constitute the “blurry outlines” that Palmer and Stevens say have been settled. The cartoon character, like a skilled but deceptive lawyer, leaves out the other part of the picture.

  8. 158
    Mal Adapted says:

    David Young:

    Advocating against strong mitigation measures is a position that while unpopular with alarmists, does not imply ”denial” of any science

    OK, now we’re getting somewhere. Since science isn’t a popularity contest, it turns out we’re not actually arguing about science at all. With that in mind: if you want to defend your “unpopular” position, please tell us what it is, in sufficient detail to distinguish it from a more popular one! But you’re a denier until you recognize the social cost already being paid for the fossil carbon the global economy has transferred to the atmosphere in three centuries, and the reasonable certainty it will rise open-ended as long as you’re “free” to socialize your own marginal emissions costs. At the very least, you’re a non-expert denying that the lopsided consensus of actual experts is superior to your personal judgment. That may be forgivable (you decide, I can’t stop you), but it’s never respectable. Unless of course you’re proved right – hey, pigs might fly – but I’ll bet on Occam’s Razor in the meantime.

    You disclose your ideological lukewarmism by arguing against unspecified “strong” mitigation measures, and referring to strawman proponents of such measures as “alarmists”. Disregarding Steven Mosher’s efforts to claim the word, you demonstrate that lukewarmism is a species of denial: namely, of the tragedy (def. 1) of the climate commons. I acknowledge you may place little value on global biodiversity despite, for example, America’s “popular” collective valuation. What, though, is your best estimate of AGW’s aggregate cost in dollars, homes, livelihoods and lives to date, that would otherwise not be lost? Do you think it’s greater than zero? Is the loss of one harbor-side squatters’ boat, the family’s sole means of subsistence, a tragedy for you? If a single additional death from storm, flood, heatwave or wildfire is a tragedy, is a million deaths a mega-tragedy or just a statistic? How much aggregate extra tragedy would persuade you to support “strong” measures? An order-of-magnitude figure is acceptable!

    If you’re still with me (surprise): given that mitigation must be collective over the range of political scales, what sort of measure might be weak enough for you? Since you prefer weak collective measures, or none, how do you feel about using ever more public money for disaster relief, like Americans are already doing? How will you, Devil take the hindmost, “adapt” to inexorably rising GMST? Are you confident you won’t pay a high price yourself, perhaps far out of proportion to your lifetime emissions? Do you think you can buy enough insurance?

    Lastly, do you, or anyone else you care about, have children? Do you have any emotional stake in the future at all? Why else do you think we talk so much about this? Speaking for myself, it’s not because I’m a bleeding heart (OK boomer), don’t love Liberty, or want to punish anyone. I just want each of us to pay for our own marginal costs in the energy market, rather than foisting them on random involuntary third parties to include me, my brother, his daughter and her son, unto the nth generation. You know damn well that voluntary private efforts to eliminate one’s carbon footprint, no matter how strenuous, won’t be enough to cap the warming and thus the eventual net cost, nor will market forces free of collective intervention. Yet your explicit warrant is to cast doubt on climate science as a way of trying not to fool ourselves. Believe it or not, that’s a rhetorical tactic popular with unscrupulous professional deniers: I’ll name names if you will (public figures claiming scientific credentials only). Why do you suppose your position is unpopular here? Please, David, examine your implicit warrants!

    Take your time responding. I’ve got at least as much of it to spare as you do.

  9. 159
    Al Bundy says:

    jds: JDS 110: It will be interesting to see when the last time that Atomsk’s Sanakan, Al Bundy, Barton Paul Levenson or Kevin McKinney were

    AB: dayum, BPL, I made it onto a list that includes you! Happy, happy happy

  10. 160

    #144

    Your lashing out is noted, which is ironic given your previous (incorrect) whining about ad hominems. And, as I predicted, you addressed none of the evidence cited to you. That says a lot.

    Your further comments show you don’t know the basics on the topic you’re discussing. For example, the claim that models can’t predict the rate of future warming is debunked by Hausfather et al., the very paper being discussed in the RealClimate article. The temperature pattern point is also rebutted by Manabe + Stouffer 2017 (“Assessing temperature pattern projections made in 1989”), one of the very model-based papers discussed in Hausfather et al. I even cited this paper for you again in #141. At this point, it’s clear you are too busy ranting about cartoons (whatever that’s about) to read and understand the published literature.

    Palmer + Stevens’ paper does nothing to undermine the accurate predictions listed before, nor change the fact that non-quantitative predictions are useful (ex: for causal attribution of warming), nor change the fact that various contrarians screwed up on these non-quantitative predictions, etc. Cherry-picking one metric (absolute surface temperature) does not rebut decades of accurate predictions on numerous other metrics.

  11. 161
    Mal Adapted says:

    Dan H.:

    It matters not if someone is an anti-vaxer, anti-GMOer, or anti-evolutionist. Their scientific work regarding climate change should stand on its own. Similarly, ones religious views are irrelevant also (would you dismiss Einstein’s theories because of his religious views?)

    As expected, Dan H. denies denial, his own and others’. Current versions of Roy Spencer’s published work with satellite data have been good enough to enter the store of justified knowledge along with other temperature records since 1979, with the recognition they measure distinct phenomena. One more time, however: his “strong, professional opinion” that the Universe is intelligently designed and that most of the warming is natural, is exposed as sheer magical thinking by his signature under these words:

    WHAT WE BELIEVE

    We believe Earth and its ecosystems—created by God’s intelligent design and infinite power and sustained by His faithful providence —are robust, resilient, self-regulating, and self-correcting, admirably suited for human flourishing, and displaying His glory. Earth’s climate system is no exception. Recent global warming is one of many natural cycles of warming and cooling in geologic history.

    and

    WHAT WE DENY

    We deny that Earth and its ecosystems are the fragile and unstable products of chance, and particularly that Earth’s climate system is vulnerable to dangerous alteration because of minuscule changes in atmospheric chemistry. Recent warming was neither abnormally large nor abnormally rapid. There is no convincing scientific evidence that human contribution to greenhouse gases is causing dangerous global warming.

    Right, so much the worse for the multiple, consilient lines of evidence accumulated by generations of trained, genuine skeptics over two centuries, as redundantly verified by Spencer’s professional peers: an alleged Intelligent Designer with the power to suspend the laws of physics told Spencer global warming isn’t “dangerous”, and that’s good enough for him. Spencer’s religious faith, IOW, permits him to declare Truth by direct apprehension, leaving no room for skepticism. If I were asked to review for publication (not that I ever expect to be, of course) a paper on which he was first author, I’d start with the assumption he’s fooling himself. Would I be the only one? If he wants to escape that cloud of suspicion, he can start by repudiating his signature on the Evangelical Declaration on Global Warming. I wonder what it means that Spencer’s colleague and co-religionist John Christy has not signed the Declaration, although he’s proudly exhibited by the Cornball Alliance as another right-thinking climate scientist.

    Note that devout religious faith need not interfere with a scientific commitment to not allowing oneself to be fooled about the verifiable universe: I offer you Kenneth Miller on evolution and Katherine Hayhoe on climate change. Spencer complained on his blog that if climate realists were fair, we’d criticize Hayhoe for her religion too! Way to miss the point, Roy. Dan H. too, BTW.

  12. 162
    Al Bundy says:

    David Young: while unpopular with alarmists ::snip:: So, can we just dispense with the political smears?

    AB: Apparently you can’t

  13. 163
    William Jackson says:

    Is #144 meant to make sense?

  14. 164
    David Young says:

    #152, It is easy to show that US net imports of primary energy have been falling rapidly and are now close to zero.

    https://www.eia.gov/todayinenergy/detail.php?id=39392

    Since 2000 US natural gas production has increased by about 60%. Since conventional production has been on a long term decline for 30 years, this must be due almost totally to fracking.

  15. 165
    David Young says:

    #158. I’m not going to indulge in a policy food fight with you since it is a matter of priorities and not of science. My condolences on your long winded exposition that no one will read.

    The point which I guess you are acknowledging is that Spencer is NOT a science denier at all.

  16. 166
    David Young says:

    #147. The problem here is that this comment section is infested with anonymous non-scientists who never respond directly on any scientific point while attacking scientists in very vile terms. The cartoon character is particularly obnoxious. More like Wiley Coyote than like Sanakan though. I note Nijel that you too are anonymous and it would seem ignorant of science. Can you say anything that is remotely interesting or that points to something with scientific substance? If so I would be happy to learn from it. Otherwise, my condolences.

  17. 167
    David Young says:

    Wiley Coyote (aka Sanakan), I anticipated your response and it adds nothing. See #157. As to the pattern of warming, I don’t know where you pulled your paper, but I believe it is acknowledged by virtually everyone that SST patterns of warming are quite wrong in GCMs for the last 30 year period unless that pattern is prescribed as a boundary condition.

    From Palmer and Stevens: “Figs. 2 and 3 develop this point further by showing how, on the regional scale and for important regional quantities (7), these prob- lems are demonstrably more serious still, as model bias (compared with observations) is often many times greater than the signals that the models attempt to predict.”

    There are many papers on this SST pattern effect. Here’s a very recent example:

    https://www.giss.nasa.gov/meetings/cfmip2019/s2/5_nicholas_lewis_c.pdf

  18. 168
    Russell says:

    101: BP

    BPL: But [TTAPS] passed peer review, didn’t it? This is what I mean by saying for you, the issue is inextricably bound up with politics. Sure, Sagan used the results to push his political views. That’s completely irrelevant to whether the results were valid or not. In fact, it’s an ad hominem argument, and you can’t seem to stay away from those. MY point is, nuclear winter studies use an adequate plume height algorithm, and something is wrong with the nuclear autumn studies because they inevitably find a plume height three times lower, which is similar to the unit error I found at EIA in 1982.”

    BP, it’s hard to criticize TTAPS “plume height algorithm because the one dimensional model that gave rise to the term ‘nuclear winter’ didn’t have one– the model’s smoke magically materialized in the stratosphere because the systems programmer set the optical depth to e20 at T = 0. That oversight did not prevent ‘nuclear winter’ being advertised as a “robust” result of smoke soaring into the stratosphere as an ordinary result of large fires

    TTAPS gained accelerated publication in _Science_ not via ordinary peer review, but a closed DIY review conference with attendees chosen by the authors. Which is why the baloney alarms went off so loudly as soon as it was published.

    The invitees were evidently united in a disposition to ignore, in the name of the Precautionary Principle, the inability of convection to reliably propel aerosols past the tropopause, witness that wildfires transport smoke into the stratosphere only once in blue moon.

    It didn’t happen when test fires were set in Canadian forests to test that TTAPS hypothesis, and even the sooty Kuwait oil fires failed to do it. : it instead took another three decades for a forest fire and a stratocumulus thunderstorm to combine to produce such an exotic event. Please read the Los Alamos paper linked above to gain some insight into why realistic GCM models have failed to replicate the ‘nuclear winter’ result.

  19. 169

    David Young said:

    “#152, It is easy to show that US net imports of primary energy have been falling rapidly and are now close to zero.

    https://www.eia.gov/todayinenergy/detail.php?id=39392

    Since 2000 US natural gas production has increased by about 60%. Since conventional production has been on a long term decline for 30 years, this must be due almost totally to fracking.”

    I should have guessed that David Young would respond with natural gas, which is very expensive to export or import as it needs to be liquefied, thus the net on that is more of a tenuous balance. So grant the USA as a net exporter of NG — no big deal.

    But Young tops it off with a link to refined petroleum products, which means that if the USA imports crude oil and then refines it in the USA, it can count as an export! That’s a Trump-trick of double counting. Look at the unrefined crude itself and there is a huge net import need for oil — 20 million barrels per day consumed in the USA while only 10 million barrels extracted from native reservoirs.

  20. 170
    Dennis N Horne says:

    166. David Young says: The problem here is that this comment section is infested with anonymous non-scientists who never respond directly on any scientific point while attacking scientists in very vile terms.

    No, the problem here is you believe your judgement is better than experts like Gavin Schmidt and Zeke Hausfather, and the vast majority of climate scientists who trust their judgement, and will continue to do so until the evidence suggests otherwise.

    You prefer to pick out a few people who may be now or at one time qualified to comment as experts but who have been shown to be wrong. If such people refuse to admit error, then it is reasonable, on a blog, to discuss why.

    Because the problem humans face now is not so much science as human behaviour.

  21. 171

    DY 165: Spencer is NOT a science denier at all.

    BPL: You don’t think his creationism makes him a science denier? I do. Then there’s his idea that warming will be “minimal” and will not require any strong policy responses, which certainly flies in the face of what we’re already seeing. Spencer is an unusually well-educated science denier, but he’s still a science denier.

  22. 172
    Ray Ladbury says:

    David Young,
    Whether or not climate models are “fit for purpose” depends on the purpose to which they are being applied. Certainly, they are sufficient to demonstrate that adding more CO2 to the atmosphere carries with it significant risks that are difficult to bound. Indeed, the observable evidence even at present is sufficient to draw the same conclusion.

    Your assertion that the known issues with climate modeling justify inaction is simply perverse. It goes against every tenet of risk management. If the threat is known to pose severe risk and the models are inadequate to bound the risk, this argues for even more stringent action to avoid the threat, not less.

    Indeed, immediate action becomes all the more important not just to avoid the threat, but also to allow climate models time to improve so that they can be used to guide future policy. Thirty years of denial and delay have denied us the luxury of moderate action. Specious arguments like yours are why we are in this situation.

    So, if you have something that illuminates the current situation, by all means say it. If you have suggestions for how climate models can be improved. If you have suggestions for measures that can buy us time, I’m all ears. But to suggest that shortcomings in the models justify continued inaction is just flat wrong and irresponsible.

  23. 173
    Mal Adapted says:

    David Young:

    I’m not going to indulge in a policy food fight with you since it is a matter of priorities and not of science.

    The irony increases. It’s not really about science with you! While my preference for revenue-neutral carbon taxes is known, we aren’t talking about particular policies here. Our difference is down to some collective action to decarbonize, versus none. Adult citizens of any nominally democratic nation are wisely wary of political sausage making, but the need to act collectively is stark. AFAICT, your warrant in the climate blogosphere is to advocate against any collective action at all. There have been enough reports of clear and present climate crisis, and calls for collective action, in the pages of Nature and Science recently to show your position is contrary to the personal consensus of climate scientists, which is presumably informed by their scientific consensus. Whatever your deeper motive, it’s clear from your comments that you deny the tragedy of the climate commons. In my purely subjective evaluation, to deny the tragedy of AGW’s victims is vile.

    DY:

    My condolences on your long winded exposition that no one will read.

    It seems you read at least enough of it to misinterpret ;^). In any case, I don’t mind calling out your anti-social warrant at length. You’re not my only audience, you know. It appears at least some other RC commenters agree with me. Your peevish retorts suggest we’re getting to you. So as long as you’ve got the time to propagate pernicious nonsense, I’ve got the time to call it out in detail. If you want me to stop, all you have to do is keep your denial to yourself.

  24. 174
    David Young says:

    #170. What a baseless and silly comment. I agree with most scientists about climate models including Palmer and Stevens and virtually all CFD scientists who are courageous enough to be fully honest (Palmer and Stevens remove the veil on why most remain silent). If you have something scientific to say I’m interested, otherwise my condolences.

  25. 175
    David Young says:

    #150. JCH you waste keystrokes on another baseless and irrelevant comment. Of course Palmer and Stevens have to be “mindful” of their statements being misused, but that’s true of every thing ever written in a scientific journal. The real question is why do they feel the need to say this as every literature human being knows it? It’s odd to say the least since its not scientific. It’s related to their policy preferences of course. And why have their observations not been published before despite the fact that they are blindingly obvious? My condolences on not having anything scientific to contribute.

  26. 176
    Mal Adapted says:

    David Young:

    The problem here is that this comment section is infested with anonymous non-scientists who never respond directly on any scientific point while attacking scientists in very vile terms.

    David, I’ve been “Mal Adapted” everywhere on the Internet for 12 years now. Anything appearing on RC under that pseudonym is mine. I’ve had ample confirmation of the wisdom of pseudonymity, along with my reliance on blog owners to preserve it. How long have you been “David Young”? Can you prove you’re a real person? I’m skeptical!

    Never mind, I don’t want to know where you live. Your claims on this thread reduce to “coupled-GCM projections are too uncertain to justify ‘strong’ collective action”. They’re speciously scientific at best, not meriting substantive rebuttal. This much science is settled: the human cost, in money and tragedy, due to AGW is already greater than zero; the best models we can develop project increasingly severe impacts, and ever more costly adaptation, as long as net transfer of geologic carbon to the atmosphere continues; and while fossil-fuel, cement and livestock producers will enjoy short-term profits by socializing their carbon costs, billions of people will eventually suffer losses out of proportion to their private contributions to the problem. Contradictory claims are extraordinary, yet no extraordinary new evidence has been presented. IOW: consciously or not, you’re willing to go out on a scientific twig to deny other peoples’ tragedy. Once again, I think that’s vile.

    And of course you don’t agree magical thinking by trained scientists, about climate or anything else, is denial. Deniers deny!

  27. 177
    David Young says:

    Paul P, If you can point me to some documentation in a reliable source for your assertion about oil derived products from foreign oil not being correctly accounted for by the US government, I’d be interested.

  28. 178
    Jim Eager says:

    DY 165: Spencer is NOT a science denier at all.

    Hmmm, let’s see, creationism, also legally known as intelligent design, pretty much requires denial of not just evolution, but of paleontology, geology much of astronomy, and even substantial aspects of basic physics and chemistry.

    And to believe that “Earth and its ecosystems…are robust, resilient, self-regulating, and self-correcting, admirably suited for human flourishing” pretty much requires denial of any evidence of episodes of hothouse or snowball climate excursions in Earth’s past. And then there are those nasty consequences of the “minuscule changes in atmospheric chemistry” of the PETM.

    Nah, no science denial to see here. Not much, anyway.

  29. 179
    David Young says:

    I’ll just reprise something from Palmer and Stevens because it applies very well to Ladbury, Mal, Eager, Barton, Horne and several others who are driving down irrelevant tangents about policy and doing unsubstantiated personal attacks with no knowledge, no research, and little knowledge of the relevant science.

    “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.”

    There is plenty of strong substantiation of this conclusion in the literature. It’s not just climate science either but most fields that rely on CFD simulations.

    I don’t even read the long winded and substance free comments because they have no scientific content and there is no opportunity to learn from them.

  30. 180
    Ray Ladbury says:

    David Young, so I’ll take your #179 as saying, “I got nothin'”. Repeating what you’ve said before does not advance the discussion. And if you cannot be bothered to read 224 words, then I think we are safe to dismiss your monomaniacal screeds.

  31. 181

    R 168: wildfires transport smoke into the stratosphere only once in blue moon.

    BPL: Volcanoes transport aerosols into the stratosphere all the time.

  32. 182

    DY 279: I’ll just reprise something from Palmer and Stevens because it applies very well to Ladbury, Mal, Eager, Barton, Horne and several others who are driving down irrelevant tangents about policy and doing unsubstantiated personal attacks with no knowledge, no research, and little knowledge of the relevant science.

    BPL: I have little knowledge of the relevant science?

    You haven’t Googled any of us, have you? I’ll just use myself as an example, since I’m the one I know best. I have a degree in physics from Pitt (dual physics and computer programming major). I have three published papers in planetary astronomy in peer-reviewed journals, two of them on planet surface temperatures, and two more presently under peer review. You can download my essay on how to write radiative-convective atmosphere models from my web site. So where did you get the idea that I had “little knowledge of the relevant science?”

  33. 183

    #179, DY–

    You think that’s responsive to your critics here? I don’t.

    In particular, Palmer and Stevens’s ‘blurry picture’ is more than sufficient to support everything Ray pointed out:

    For certain, some things are settled. We know that greenhouse gases are accumulating in the atmosphere as a result of human activity and that they are largely responsible for warming of surface temperatures globally. We also are confident in our understanding as to why this warming is expected to be amplified over land masses and the Arctic. Likewise, we are confident in our understanding of how the hydrological cycle amplifies the effects of this warming and how warming amplifies the hydrological cycle. For these and other broad brush strokes of the climate change picture, we are also increasingly confident in our ability to usefully bound the magnitude of the effects. From this certainty stems the conviction that additional warming is best avoided by reducing or reversing emissions of long-lived greenhouse gases.

    …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. Rather, it stems from our ability to link observed changes in climate to changes derived from the application of physical reasoning, often as encoded in much simpler models or in the case of the water cycle, through a rather simple application of the laws of thermodynamics. Comprehensive climate models have been effective and essential to address the concern that such a basic understanding could be overly simplistic (i.e., missing something important, such as the existence of a mode of internal variability, which could, if it were to exist, explain trends in global mean temperature). The enterprise of making models more and more comprehensive through the incorporation of computationally expensive* but poorly understood additional processes has not so much sharpened our ability to anticipate climate change as left the blurry picture established by physical reasoning and much simpler models intact (1). When it comes to global climate change, it is what the present generation of comprehensive climate models do not show—namely, a sensitivity of global changes to either the vagaries of unpredictable regional or global circulations or effects of processes neglected in simpler models—which makes them such a powerful confirmation of inferences from basic physics and simple models.

    THAT is the setup to the bit you quote. IMO, you misrepresent the very researchers upon whom you rely.

  34. 184
    Mal Adapted says:

    David Young insists he’s talking about science. He quotes Palmer and Stevens:

    “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.”

    I suspect that sounds familiar to most experienced principle investigators. The authors do not claim to overturn the consensus of their peers for AGW. Nor do they offer comfort to lukewarmers (my emphasis):

    For certain, some things are settled. We know that greenhouse gases are accumulating in the atmosphere as a result of human activity and that they are largely responsible for warming of surface temperatures globally. We also are confident in our understanding as to why this warming is expected to be amplified over land masses and the Arctic. Likewise, we are confident in our understanding of how the hydrological cycle amplifies the effects of this warming and how warming amplifies the hydrological cycle. For these and other broad brush strokes of the climate change picture, we are also increasingly confident in our ability to usefully bound the magnitude of the effects. From this certainty stems the conviction that additional warming is best avoided by reducing or reversing emissions of long-lived greenhouse gases.

    As climate scientists, we are rightfully proud of, and eager to talk about, our contribution to settling important and long-standing scientific questions of great societal relevance. What we find more difficult to talk about is our deep dissatisfaction with the ability of our models to inform society about the pace of warming, how this warming plays out regionally, and what it implies for the likelihood of surprises. In our view, the political situation, whereby some influential people and institutions misrepresent doubt about anything to insinuate doubt about everything, certainly contributes to a reluctance to be too openly critical of our models. Unfortunately, circling the wagons leads to false impressions about the source of our confidence and about our ability to meet the scientific challenges posed by a world that we know is warming globally

    How can we can reconcile our dissatisfaction with the comprehensive models that we use to predict and project global climate with our confidence in the big picture? The answer to this question is actually not so complicated. 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…

    David may have found the above excerpt TL;DR, but I’ll be surprised if RC’s climate realists disagree with any of it. How many times does it need to be said: “all models are wrong, but some are useful”? Our confidence in the big picture is not primarily derived from the fidelity of the CMIP6 ensemble, in any event. No circling the wagons here! Palmer and Stevens’ conclusions still can’t be construed to support letting David Young socialize his marginal climate-change costs. Sorry, David, but no. If that’s not what you’re here to talk about, then stop misrepresenting doubt about anything to insinuate doubt about everything, and complaining about the unpopularity of your position!

    That’s my position, FWIW. Ain’t “free” (i.e. cheap) speech grand? Thankfully, you’re no more influential than I am.

  35. 185
    nigelj says:

    David Young @166, I have given you plenty that is interesting about “The Science”. For example my link on what Roy Spencer has said about “The Science” and how wrong he is, over and over again. I repeat it below, and it includes a huge list of his quotes, articles, blogs, and research etcetera, and hard evidence of why he’s consistently been wrong. Sort of a collection of his Greatest Non Hits:

    https://skepticalscience.com/skeptic_Roy_Spencer.htm

  36. 186
    nigelj says:

    David Young @179 says “I don’t even read the long winded and substance free comments because they have no scientific content and there is no opportunity to learn from them.”

    Yes neither do I, and as such I no longer bother with your comments.

  37. 187
    Paul Pukite says:

    David Young said:

    “Paul P, If you can point me to some documentation in a reliable source for your assertion about oil derived products from foreign oil not being correctly accounted for by the US government, I’d be interested.”

    https://www.eia.gov/tools/faqs/faq.php?id=727&t=6

    “In 2018, the United States imported about 9.94 million barrels per day (MMb/d) of petroleum from nearly 90 countries. Petroleum includes crude oil, hydrocarbon gas liquids, refined petroleum products such as gasoline and diesel fuel, and biofuels including ethanol and biodiesel. Crude oil accounted for about 78% of U.S. gross petroleum imports in 2018, and non-crude oil petroleum accounted for about 22% of gross petroleum imports.

    In 2018, the United States exported about 7.60 MMb/d of petroleum to about 190 countries and 4 U.S. territories, of which about 27% was crude oil and 73% was non-crude oil petroleum. The resulting net imports (imports minus exports) of petroleum were about 2.34 MMb/d.

    So the USA exports about 27% of 7.6 million barrels or ~ 2 million barrels a day derived from crude oil, while we all know that the USA economy consumes over 20 million barrels of oil a day. The lie of the Trump admin is that the USA has an inexhaustible reserve supply of crude oil, whereas the exact opposite is true.

    Eventually, because crude oil is a finite and non-renewable resource, this disinformation can only be presented for so long. Already, the latest solution to providing the USA a homegrown oil independence future — via shale oil from Texas and North Dakota is showing a depletion backside.

    https://www.wsj.com/articles/banks-get-tough-on-shale-loans-as-fracking-forecasts-founder-11577010600

    “Banks Get Tough on Shale Loans as Fracking Forecasts Flop
    Oil and gas companies face tightened credit after wells produce less than projected

    This was all well known by anyone that follows the production numbers. These fracked shale oil wells only last a few years on average and unless more are drilled than get depleted, a net decline will set in. The prime locations are being picked clean and the second-rate wells are not panning out.

  38. 188

    #187, PP–

    The lie of the Trump admin…

    Would that there were only one! But the biggest is that we can afford in any sense to keep burning FF.

  39. 189
    David Young says:

    Mal and Kevin quote from the “blurry outlines” part of Palmer and Stevens as if its important. These blurry outlines are not new and were known 40 years ago. Energy balance models also give us this quite approximate information. The important thing in Palmer and Stevens is the admission of what everyone who knows the mathematical details has known for 40 years (even Hansen knew it), namely that beyond what simpler models tell us, GCM’s are not fit for purpose. That is the import of the paper.

    ECS from models has a large range which implies that they cannot predict future warming even to within a factor of 2 or 3. That past warming seems to be somewhat predicted is due to tuning to TOA radiative balance.

    For Ladbury’s benefit, reading is a helpful skill that I would urge you to go back to high school to learn. I never said that action should not be taken. I said that Spencer didn’t think urgent action was needed.

  40. 190
    Mal Adapted says:

    David Young:

    GCM’s are not fit for purpose.

    Whose purpose? The current generation of GCMs leave no room for doubt there will be future climate change greater than there has been to date, the cumulative cost will grow higher, and it won’t be capped until we stop transferring carbon to the atmosphere. Palmer and Stevens agree that the current CMIP ensemble though “blurry”, provides sufficient certainty to support specific collective action:

    From this certainty stems the conviction that additional warming is best avoided by reducing or reversing emissions of long-lived greenhouse gases.

    They then impose a more stringent purpose:

    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.

    …for many key applications that require regional climate model output or for assessing large-scale changes from smallscale processes, we believe that the current generation of models is not fit for purpose.

    I understand they’re not good enough for a couple of dedicated professional climate modelers, or David Young. They’re plenty fit for my purpose, to wit: putting a cap on open-ended global catastrophe, within my great-nephew’s lifetime if not my own. I sympathize (maybe, a little) with politicians who want accurate year-by-year predictions for their districts. They’re just going to have to govern without that kind of precision. They can at least be sure the costs of AGW to their constituents are mounting while they wait for better GCMs. More confident, detailed predictions will never convince hard-core denialists anyway. Current GCMs are fit to justify a positive lower-bound estimate of the social cost of carbon. Or else the observed costs in the last 5-10 years can be used: “confidence in the big picture is not primarily derived from the fidelity of comprehensive climate models.” A carbon tax of some sort is only controversial with voters, not with economists. A low initial per-ton fee can be raised later, based on the progress of emissions reductions. What are we waiting for? Well, it might help if David stops “misrepresent[ing] doubt about anything to insinuate doubt about everything”. Not just him of course, but influential people as well.

  41. 191

    DY 189: I said that Spencer didn’t think urgent action was needed.

    BPL: Spencer was wrong.

  42. 192

    #189, DY–

    No, you quoted the ‘blurry outlines’ part. Repeatedly, in fact.

    What Mal and I quoted was the two preceding paragraphs that make it quite clear that if your ‘purpose’ is to discern the need for strong mitigative action, then climate modeling is quite “fit”. Not sure that any amount of highlighting, citing or repetition will be sufficient to help you understand something you are clearly determined not to grasp, but:

    Palmer and Stevens describe as “settled” or “certain” these things:

    –greenhouse gases are accumulating in the atmosphere as a result of human activity
    –they are largely responsible for warming of surface temperatures globally
    –this warming is expected to be amplified over land masses and the Arctic
    –hydrological cycle amplifies the effects of this warming and how warming amplifies the hydrological cycle

    Bottom-line conclusion:

    From this certainty stems the conviction that additional warming is best avoided by reducing or reversing emissions of long-lived greenhouse gases.

    IOW, Palmer and Stevens, whom you cite as support for the notion that climate modeling does not support mitigation, explicitly opine that climate modeling supports mitigation. In fact, in the last sentence I quote–and the last one, in full context, before the paragraph you cite goes so far as to call climate model results:

    a powerful confirmation of inferences from basic physics and simple models.

    That is why I call your citation “misleading”, and I fail to see any reason now why I was in any way unfair or incorrect in doing so. That you now double down on your characterization strains the power of disingenuity as an explanation. Palmer and Stevens quite simply do not propound the conclusion that you claim.

    Somewhat ironically, you are instead a textbook example of something else they say in that paragraph:

    …the political situation, whereby some influential people and institutions misrepresent doubt about anything to insinuate doubt about everything, certainly contributes to a reluctance to be too openly critical of our models.

  43. 193
    Ray Ladbury says:

    David Young: ” I never said that action should not be taken. I said that Spencer didn’t think urgent action was needed.”

    Yes, I’ve noticed you do that a lot–say nothing about what you think is required while highlighting the advocacy for inaction of a denialist who you then pretend is in not a crank. I don’t think the “I am too cowardly to advocate my own point of view” defense is going to help you particularly. Nor does it do you credit.

  44. 194
    Mal Adapted says:

    David Young:

    I never said that action should not be taken. I said that Spencer didn’t think urgent action was needed.

    Spoken like a politician, David. A while back you said:

    BTW, Advocating against strong mitigation measures is a position that while unpopular with alarmists, does not imply “denial” of any science. Policy is a matter of values and priorities, not science

    You may claim you were only defending Spencer, but we weren’t fooled: you, David Young, are here to advocate against “strong” mitigation measures. Your “science” is limited to strenuously hyping the uncertainty of current climate models, but your cited source isn’t helping you (my bolding):

    For these and other broad brush strokes of the climate change picture, we are also increasingly confident in our ability to usefully bound the magnitude of the effects. From this certainty stems the conviction that additional warming is best avoided by reducing or reversing emissions of long-lived greenhouse gases.

    Despite your refusal to say so out loud, your warrant on climate blogs is to advocate against “urgent” action. We claim that’s a matter of your anti-collective political values, not science. Prove us wrong: tell us what “weak” mitigation measures you advocate, against what “strong” ones, and give us quantitative arguments why you think they will, not might, forestall global climate catastrophe within my toddler great-nephew’s lifetime. If you can’t, then for the love of all we hold dear, would you please (trigger warning) STFU about models? It’s time to [bleep!] or get off the pot, David!

    BTW, Kevin McKinney (your bolding):

    Somewhat ironically, you are instead a textbook example of something else they say in that paragraph :

    …the political situation, whereby some influential people and institutions misrepresent doubt about anything to insinuate doubt about everything, certainly contributes to a reluctance to be too openly critical of our models.

    I agree but for the “influential” part!

    Moderators: it’s been kind of fun, and as long as David keeps flailing away, I’ve got time to hit him back. Now that we all know this admittedly tedious Internet slapfight isn’t about science, however, should it be moved to the FR thread?

    All: or, are we ready to drive a stake through the “models are unreliable” (because two guys said something that sounded like that in PNAS) meme’s undead heart, and content ourselves with eviscerating David’s comments on other threads? If you can’t get enough of him on RC, he occasionally appears with the same schtick on ATTP and Open Mind. Similar hilarity ensues ;^).

  45. 195
    Dennis N Horne says:

    @ Mal Adapted. You might just “correct” Cambridge professor Michael Joseph Kelly FRS; be appreciated if you could. Thanks.
    https://www.climateconversation.org.nz/2020/01/mike-kelly-cool-agile-under-bbc-4-climate-grilling/

    [Response: The page to correct him is right here. – gavin]

  46. 196
    Al Bundy says:

    David Young: ECS from models has a large range which implies that they cannot predict future warming even to within a factor of 2 or 3.

    AB: Yep, but the distribution isn’t mirror-image. It is highly unlikely that warming will be seriously less than what’s expected. So this half of the distribution is tightly constrained.

    However, the other half of the distribution is not well constrained at all, resulting in the “long tail” problem. The long tail does mean that future warming possibilities are widely distributed, but how does that even slightly affect the tightly bound short tail of the ‘less warming’ side? “Uncertainty is not your friend”, remember?

    Ain’t it a hoot how dishonest folks can twist durn near anything into an opposite conclusion? Then there are the parrots who spread said twist and the resulting conclusion far and wide. What’s your part in this, David? Where did you get that “factor of 2 or 3” stupid as Hell (but effective) argument?

  47. 197

    #157, Re: “Another statement by Palmer and Stevens summarizes perfectly the cherry picking at the heart of the cartoon character’s deception. […] The papers cited by the cartoon character constitute the “blurry outlines” that Palmer and Stevens say have been settled. The cartoon character, like a skilled but deceptive lawyer, leaves out the other part of the picture.”

    Your obsession with cartoon characters is noted. Also, as other people have pointed out (ex: #183, #184, #192), you’re abusing Palmer+Stevens’ work to manufacture false doubt on topics you don’t even understand, and to avoid policies you’re politically opposed to.

    #166, Re: “#147. The problem here is that this comment section is infested with anonymous non-scientists who never respond directly on any scientific point while attacking scientists in very vile terms. The cartoon character is particularly obnoxious. More like Wiley Coyote than like Sanakan though. I note Nijel that you too are anonymous and it would seem ignorant of science.”

    That’s just evidence-free complaining on your part. Whether someone is anonymous is irrelevant to the discussion and the points being made. Like your continuing references to “cartoon[s]”, it’s just you finding a red herring to lash out about (while you, ironically, complain about supposed ad hominems).

    #167, Re: “Wiley Coyote (aka Sanakan), I anticipated your response and it adds nothing. See #157. As to the pattern of warming, I don’t know where you pulled your paper […]”

    It’s cited in Hausfather et al., as I already explained to you, along with giving you the reference. So not only do you not bother to closely read the posts you’re responding to, but you likely didn’t even bother to read the paper this RealClimate post is about. Typical for you.

    #167, Re: “[…] but I believe it is acknowledged by virtually everyone that SST patterns of warming are quite wrong in GCMs for the last 30 year period unless that pattern is prescribed as a boundary condition.
    From Palmer and Stevens: “Figs. 2 and 3 develop this point further by showing how, on the regional scale and for important regional quantities (7), these prob- lems are demonstrably more serious still, as model bias (compared with observations) is often many times greater than the signals that the models attempt to predict.””

    You’ve shown you don’t even read much of the peer-reviewed literature, so your “belie[fs]” about what “is acknowledged by virtually everyone” are not to be trusted. You’re likely just repeating something Nic Lewis or Judith Curry said on their blog, without you bothering to check it aginst the literature.

    Your reference to Palmers + Stevens Paper again doesn’t help your case here; your’e just again using it to avoid the evidence cited to you. Also, please familiarize yourself with the distinction between temperature change (temperature anomaly) vs. absolute temperature.

    #167, Re: “There are many papers on this SST pattern effect. Here’s a very recent example:
    https://www.giss.nasa.gov/meetings/cfmip2019/s2/5_nicholas_lewis_c.pdf

    That’s not a peer-reviewed paper; that’s a bunch of PowerPoint slides from Nic Lewis. So thanks for again illustrating what I said in #141: “[…] your familiarity with climate science boils down to reading blog articles from Nic Lewis + Judith Curry, and only being familiar with a handful of papers they point you towards.”

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