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Unforced Variations: Apr 2018

Filed under: — group @ 1 April 2018

This month’s open thread for general climate science discussions.

321 Responses to “Unforced Variations: Apr 2018”

  1. 201
    Toni Massari says:

    I just wanted to ask what the general consensus is on THIS article and the data contained therein?

  2. 202

    TM 201: I just wanted to ask what the general consensus is on THIS article and the data contained therein?

    BPL: That it’s right-wing political propaganda and you’d do better to get your science from the science literature.

  3. 203
    Ric Merritt says:

    For Toni Massari currently #201:

    That Forbes article is garden-variety denier doofusity. The scattered bits of temperature data mentioned in the article don’t even pretend to support the “Global Cooling” of the headline.

  4. 204
    Ray Ladbury says:

    Toni Massari,
    Pray, why are you asking for commentary on a 5-year old article by a non-climate scientist–particularly one which looks so freaking silly now in the aftermath of several back-to-back record warm years, a very warm 2017 (despite no El Nino) and the general failure of the author to understand the difference between weather and climate.

    Granted, schadenfreude has a certain entertainment value, particularly when an utterly clueless author is so thoroughly discredited by subsequent events. However, given Mr. Ferrara’s association with the Heartland Institute, he ought to be used to looking silly.

  5. 205
    Douglas says:

    Thanks again to all that have responded to my inquiries regarding if several extremely rich folks (billionaires) got behind some climate initiatives, what should they focus on? Nobody really mentioned something that I did a lot of research on yesterday, which was pushing for a carbon tax. I am convinced now that this is one of the most useful things we could do. So, I may very well try the herculean task of trying to get some very rich people behind the idea of a carbon tax-people that fund the major political parties (This is because where the money is, politicians follow).

    I am very well aware that several of these big donors benefit from the energy mix we have currently, but I am convinced that few of them (perhaps by choice) don’t really understand what we are facing regarding global warming. So, I am going to make an attempt to figure out how to contact these folks, educate them, and hope that they will fund political efforts to implement a carbon tax. Like I said, it is a herculean task, and I know what I’m up against, but I’m going to give it a real shot. I checked out what Tom Steyer is doing with climate and it appears funding efforts to implement a carbon tax is not even on his radar. Of course, we would have a better chance of success if we had some Democratic control in Washington-perhaps after this year.

    I would be very open to anyone’s opinion how I can further this cause I am attempting. Thanks again everyone.

  6. 206
    Hank Roberts says:

    Toni, the general consensus on THIS article is that it’s been disproved by subsequent experience.
    I trust that you did notice you’re rebunking a piece dated May 26, 2013? So you can look up the subsequent five years to check what he said would happen.


    and page down a bit past the links to the original story to see followup information.

    You probably know how to look this stuff up for yourself. Please do.

  7. 207
    Douglas says:

    Regarding my previous comment, to have any hope of being taken seriously, I believe I will need to have some certification in climate science. Perhaps even a class or two, would “get me in the door”. I’ve been reading climate science media daily since 2009, and have spent a lot of time on this site. I do not have scientific, mathematic, or a technical background. I did start to take an online class with Richard Alley a few years ago, but didn’t complete it. Does anyone here know of some online classes, free or otherwise where I could take a few classes on climate science-preferable with some kind of certification at the end? I believe demonstrating that “I know what I’m talking about” will be the first step in attempting my effort to help to get a carbon tax eventually passed.

    Thanks again.

  8. 208
    Hank Roberts says:

    PS for Toni — when you google, use the Tools button and select “verbatim” so your search results include everything you looked for, not just any of the words. You can also put quotation marks around a string like “peter ferrara” in the search to find that string.

  9. 209
    Marco says:

    Toni, why do you want a comment on a 5 year old article? One that announces “global cooling is here” and then has the same year end up as the 7th warmest year in GISTEMP, and the subsequent years ranked 4, 2, 1, and 3, respectively. Quite the cooling!

    I guess the general consensus is “deniers being wrong – what else is new?”.

  10. 210
    Hank Roberts says:

    PPS for Toni Massari: here’s the five year average (to compare to that 2013 bogus claim of cooling you asked about)

  11. 211
    Hank Roberts says:

    PS, for those who enjoy curve-fitting, an amusement:

    Did you know that one can implement Hello World with Fourier transforms? I did not, but now I do.
    Click the Evaluate button at and prepare to be amazed.

  12. 212
    Hank Roberts says:

    Oops. in case I needed that.

  13. 213
    JCH says:

    A RealClimate article about Hay’s sea level study:

    A New Sea Level Curve

    Look at the zero line on the graph that shows the various rates of rise found in the studies included in the graph.

  14. 214
    Jtr says:

    198,199. Things do seem to have gone downhill fast since the introduction of the internet. I suspect the reason is the same as for why there’s so much road rage. Where there’s a certain amount of anonymity, people, who are so inclined, feel free to vent. Makes you wonder what’s really in our hearts and genes. What would people do if they thought they could get away with it.

    Not to be just another cynic. There are also plenty of good people out there struggling to keep things positive and constructive.

  15. 215
    Victor says:

    199 jgnfld

    “One way of not making one’s self a magnet for “mean” responses is not to accuse professional people on their own board of engaging in unprofessional, dishonest, and even outright criminal activities while at the same time purporting that one’s confused and amateurish “science” completely overturns the findings of said professionals.”

    Even if it does? Or don’t you care?

    The “mean responses” are your problem, not mine. In fact I relish them, as they only confirm the juvenile nature of so many of the self-appointed “experts” posting here. If you really want to defend “the science” of Rahmstorf and his colleagues then defend it, if you can, with cogent arguments rather than tossing out crude insults and ad hominems.

  16. 216
    Victor says:

    200 Barton Paul Levenson says:
    V 191: : the FACT that CO2 emissions could have had NO appreciable influence on sea level for roughly 70 years
    BPL: Did they have an appreciable influence on temperature in that time?

    According to most climate scientists, no. Some examples from the literature regarding the temperature rise during the 1st half of the 20th century:

    Spencer Weart: “The scientists who brushed aside Callendar’s claims were reasoning well enough. (Subsequent work has shown that the temperature rise up to 1940 was, as his critics thought, mainly caused by some kind of natural cyclical effect, not by the still relatively low CO2 emissions. . .)” from “The Discovery of Global Warming,” by Spencer Weart (

    Here’s another: “Nearly 30% of the global warming since 1900 occurred between 1910 and 1940, when increases of human-produced CO2 played a relatively minor role in global climate change.” (

    One more: “Interdecadal 20th century temperature deviations, such as the accelerated observed 1910–1940 warming that has been attributed to an unverifiable increase in solar irradiance (4, 7, 19, 20), appear to instead be due to natural variability. The same is true for the observed mid-40s to mid-70s cooling, previously attributed to enhanced sulfate aerosol activity (4, 6, 7, 12).” ( No mention at all of CO2 or greenhouse gases in the above.

    As for the following period, from ca. 1940-ca. 1979, there was a period of abrupt cooling followed by a leveling off of temperatures. This “hiatus” is accepted by just about all climate scientists. Regardless of the cause, which some have attempted to explain as due to industrial aerosol cooling, one can’t accuse CO2 emissions of raising global temperatures during a period when there was no such rise.

  17. 217
    JRClark says:

    @207 Douglas, his previous comments and the responses made to him all belong in the Forced Responses thread, don’t they? May be a good idea to transfer those comments where they belong. Here is March’s thread.

    There is no April thread? This may be why Douglas didn’t use it because he didn’t know. May be a mitigation political solutions thread isn’t wanted.

  18. 218
    Mr. Know It All says:

    190 – Douglas

    I think a good, solid, pro climate change, 3rd party candidate is the way to go if you want to do anything on CC in the USA. If that candidate has good name recognition, that would be a big plus. Let’s see, can we think of anyone? I think Jill Stein would be awesome – she’s smart as whip, well known because she’s run before, and she took on Trump and his cheating in the vote counts in those 3 states in 2016. And she could break that glass ceiling that is so crucially important.


  19. 219
    JRClark says:

    Some science perspectives and research.

    The development of subjective group dynamics: When in‐group bias gets specific
    According to a subjective group dynamics model of intergroup processes, intergroup differentiation and intragroup differentiation co‐occur to bolster the validity of in‐group norms. The hypothesis that this process develops later than simple in‐group bias was confirmed. All children expressed global in‐group bias, but differential reactions to in‐group and outgroup deviants were stronger among older children.

    The Development of Subjective Group Dynamics: Children’s Judgments of Normative and Deviant In‐Group and Out‐Group Individuals
    Children of all ages expressed intergroup bias. Differential evaluation against in‐group deviants and in favor of out‐group deviants strengthened with age. Understanding of targets’ relative acceptability (differential inclusion) among in‐group and out‐group members mediated the effects of age and intergroup bias on intragroup bias

    Group Identity and Social Preferences Abstract
    We present a laboratory experiment that measures the effects of induced group identity on social preferences. We find that when participants are matched with an ingroup member, they show a 47 percent increase in charity concerns and a 93 percent decrease in envy. Likewise, participants are 19 percent more likely to reward an ingroup match for good behavior, but 13 percent less likely to punish an ingroup match for misbehavior. Furthermore, participants are significantly more likely to choose social-welfare-maximizing actions when matched with an ingroup member. All results are consistent with the hypothesis that participants are more altruistic toward an ingroup match.

    The authors argue that people derive a sense of self-worth and social belongingness from their memberships in groups, and so they are motivated to draw favorable comparisons between their own group and other groups.

    The group-value model proposes that fair procedures matter because they communicate two symbolic messages about group membership: (1) whether individuals are respected members of a group and (2) whether they should feel pride in the group as a whole. These messages are conveyed by 3 relational aspects of the actions of authorities: actions that indicate neutrality, trustworthiness, and status recognition

    Sometimes scientific research only confirms the already obvious facts of the matter. But what is obvious to one person is sometimes not obvious to everyone. Which begs the question of how to make the knowledge found in peer reviewed science more readily accessible to, and able to be applied by all people including genuine scientists, amateur scientists, and blog fora commentators?

  20. 220
    JRClark says:

    A common concern people have, scientists included, are over the issue of climate models.

    While Stefan raises issues about the AMOC based on 2 recent papers, barely 5 years ago now the IPCC AR5 WGI SPM stated: “There is no observational evidence of a trend in the Atlantic Meridional Overturning Circulation (AMOC), based on the decade-long record of the complete AMOC and longer records of individual AMOC components.” Pg 8

    Now, suddenly, there is? I think it it reasonable for reasonable people to be somewhat shocked and surprised by such massive shifts in a scientific consensus to at least be asking questions about who or what is right or more right, and why X evidence is suddenly superseding Y evidence, or why previously accepted global climate models, regional or ocean models no longer are accepted.

    When climate scientists themselves keep arguing and disagreeing on this study, that model, that data and math versus this data and this math, including on this ‘science’ forum, it is obvious to me that those less educated and less involved in the details would also be asking some pretty serious questions about notions of credibility and reliability of the science outputs and claims from one day to the next.

    Here’s an example of what several scientists have said in a few quotes starting with 4. MODELING OF FUTURE ARCTIC SEA ICE CHANGE
    “Given the estimated trend and the volume estimate for October–November of 2007 at less than 9,000 km3 (Kwok et al. 2009), one can project that at this rate it would take only 9 more years or until 2016 ±3 years to reach a nearly ice-free Arctic Ocean in summer.” page 639

    When at almost the same time other publications were saying a nearly ice-free Arctic Ocean in summer will not occur until 2037 and not until 2100. Outputs like this from the same body of climate scientists and IPCC and other bodies demand questioning and being explained to the public with clarity in a way they can understand the answers offered.

    Other selected comments from The Future of Arctic Sea Ice, 10.1146/annurev-earth-042711-105345 , Wieslaw Maslowski, Jaclyn Clement Kinney, Matthew Higgins, and Andrew Roberts, Department of Oceanography, Naval Postgraduate School, Monterey, California 93943; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309;

    1) Abstract “Such changes could have significant ramifications for global sea level, the ocean thermohaline circulation, native coastal communities, and commercial activities, as well as effects on the global surface energy and moisture budgets, atmospheric and oceanic circulations, and geosphere-biosphere feedbacks. However, a system-level understanding of critical Arctic processes and feedbacks is still lacking.”

    2) Such processes and feedbacks directly control regional Arctic climate variability and indirectly exert control on global climate variability.

    3) However, a system-level understanding of critical Arctic processes and feedbacks is still lacking. Fully coupled global climate models (GCMs) have large uncertainties and limited skill in simulating and predicting the Arctic ice cover

    4) The majority of regional Arctic models use higher resolution compared with global models, but they do not account for important feedbacks among various system components.

    5) Model limitations are hindering our ability to predict the future state of Arctic sea ice.

    6) There are still insufficient observations of ice thickness to quantify the basin-wide and long-term rate of ice-volume change over the past several decades.

    7) The summer of 2007 is a prime example of the influence of this type of forcing. (follow the paragraph)

    8) Given the importance of atmospheric circulation in forcing sea ice growth, melt, and transport, how well do current state-of-the-art GCMs simulate the Arctic circulation?
    Although these models are useful for many aspects of climate research, based on the results presented below, we believe that further improvements are possible and needed to correctly represent the atmospheric circulation in the Arctic.

    9) In many GCMs, there are large biases in atmospheric circulation, and it seems probable that these biases will have major impacts on the ability of these models to accurately predict changes in sea ice.

    10) Part of the CMIP5 era of GCMs, the recently released Community Climate System Model version 4 (CCSM4) shows major circulation biases as compared with ECMWF 40-year reanalysis data.

    11) Over the past decade, various studies have attempted to estimate the future trajectory of Arctic climate and have proposed a wide range of projections of seasonal Arctic sea ice cover. We summarize most of these projections below to emphasize that more work is needed to minimize confusion, identify uncertainty, and advance the prediction of Arctic sea ice change. ….. Unfortunately, the majority of GCMs, including those participating in the IPCC AR4, have not been able to adequately reproduce observed multi-decadal sea ice variability and trends in the pan-Arctic region.

    12) We have analyzed results from eight of the CMIP5 models that have become available. Results for the mean September ice-thickness distributions during the time period of 2000–2004 are shown in Figure 7. Four of the models have quite unrealistic distributions of sea ice thickness for this period.

    13) The inability of climate models to adequately reproduce the recent states and trends of Arctic sea ice diminishes confidence in their accuracy for making future climate predictions. Another issue is that sea ice extent and area are parameters that only partially account for the loss of sea ice volume.

    14) The above overview of model predictions … and their limitations leads to an important conclusion. It suggests a great need for improved understanding and model representation of physical processes and interactions specific to polar regions that currently might not be fully accounted for or are missing in GCMs.

    There are many Arctic climatic processes that are omitted from, or poorly represented in, most current-generation GCMs.

    These OMITTED/POORLY Represented processes include the following: oceanic eddies, tides, fronts, buoyancy-driven coastal and boundary currents, cold halocline, dense water plumes and convection, double diffusion, surface/bottom mixed layer, sea ice–thickness distribution, concentration, deformation, drift and export, fast ice, snow cover, melt ponds and surface albedo, atmospheric loading, clouds and fronts, ice sheets/caps and mountain glaciers, permafrost, river runoff, and air–sea ice–land interactions and coupling.

    16) There are also a number of important limitations in the way sea ice and ocean models are coupled in current-generation GCMs.

    17) Sea ice is undergoing rapid decline; however, the skill in multimodel averages is relatively poor, the uncertainty in multimodel ensembles is large, and both are subject to model selection. Simple extrapolation from hindcasts sheds little light on the problem.

    18) Overall, these different modeling methodologies and results point to the ongoing need for a hierarchical approach to better understand the past and present states and estimate future trajectories of Arctic sea ice and climate.


    The IPCC AR5 WGI SPM pg 9 says in 2013: The annual mean Arctic sea ice extent decreased over the period 1979 to 2012 with a rate that was very likely in the range 3.5 to 4.1% per decade (range of 0.45 to 0.51 million km2 per decade), and very likely in the range 9.4 to 13.6% per decade (range of 0.73 to 1.07 million km2 per decade) for the summer sea ice minimum (perennial sea ice).
    The average decrease in decadal mean extent of Arctic sea ice has been most rapid in summer (high confidence); the spatial extent has decreased in every season, and in every successive decade since 1979 (high confidence)
    There is medium confidence from reconstructions that over the past three decades, Arctic summer sea ice retreat was unprecedented and sea surface temperatures were anomalously high in at least the last 1,450 years.

    There is high confidence that permafrost temperatures have increased in most regions since the early 1980s. Observed warming was up to 3°C in parts of Northern Alaska (early 1980s to mid-2000s) and up to 2°C in parts of the Russian European North (1971 to 2010).

    What seems to be so often neglected in discussions is an open admission that GCMs, from reconstructions and such are based upon guesses and assumptions that of themselves rely upon limited degrees of accurate observational evidence and further assumptions made about those observations.

    Yes, sure, they are ‘educated’ and ‘well-informed’ ‘scientifically based’ guesses and assumptions by ‘experts’ in their field however they are still only guesses. They are not definitive nor provably accurate across the board.

    Such estimations would never have put a man on the moon, except by sheer luck. Admitting this repeatedly would increase the credibility and trustworthiness of climate scientists across the board in the eyes of the public, of global policy makers and political parties in general.

    Meanwhile some policy making circles have for 30 years being demanding of scientists answers to questions that are impossible to answer accurately. The Tail keeps wagging the dog to come up with ever more definitively accurate statements as to the state of the science – in a world where the evidence is simply not available – bar an educated Guess with a degree of ‘confidence’ attributed to those guesses.

    Once some new data is found and analyses to provide a better answer immediately the ‘policy makers’ ask ever more difficult unknowns to be delivered. The climate dog keeps chasing it’s tail hoping to please it’s ‘Masters’!

    I am not saying that such research and analysis is not useful, not good or should be stopped. The point here is that what may be much more effective is to first acknowledge the serious limitations of the present outputs and to instead focus more heavily upon First Principles grounded in Philosophical Truths and Basic Logic – then communicating that is simple plain English that anyone could understand given half a chance.

    Climate Scientists, the IPCC process and the UNFCCC need to step up and say providing a definitive answer to X latest questions of how, when, why is a total waste of time, energy and resources.

    For the key answers are already self-evident in the basic science – and as such any predicted time-frame is in and of itself Moot and fundamentally irrelevant – given corrective action is already 30 years behind what should have been.

    If there were not already huge holes in the available science outputs and the huge holes in data they are based upon then people like Judith Curry et al they would not have a leg to stand on in the first place.

    Repeated attempts to publicly Minimize and discount the inherent flaws, shortcomings, assumptions and guesses in Climate Models and Observational Data summaries is no solution to gaining near global public acceptance of ones work.

    Repeatedly applying First Principles instead while using simple language is capable of short-cutting the rhetoric which points out the most obvious flaws/errors and haughty claims of the latest paper pushing their latest Climate Model supremacy.

    It’s a no win situation when science can so easily be used to undermine itself. Honesty should be the best policy. That should mean not pretending that any GCM or any model or any data set is anywhere near accurate and reliable – let alone the final conclusions and judgments based upon them that can make it through Peer Review.

    How about a healthy dose of common sense and simple logic much more often instead?

    Naturally TL:dnr is an excellent handy out to thinking about holistic first principles and considering logical responses to what is a big picture issue. It’s just the way it is.

  21. 221
    MA Rodger says:

    Toni Massari @201,
    You get responses up-thread that pretty-much go not further than call your referenced piece in Forbes ‘To The Horror Of Global Warming Alarmists, Global Cooling Is Here’ out-of-date (from 2013) and denialist clap-trap. I feel you deserve a little more explanation.

    A read of the article gets you very quickly asking ‘Who is the author of this drivel?”
    The answer is that ‘Peter Ferrara – Contirbutor’ turns out to be a denialist from the Heartland Institute. Of course, that does not stand as proof that all he writes is denialist nonsense, but it does explain why he he begins his piece writing so insistently on the subject of the Little Ice Age (a subject that is not as well-understood as Ferrara makes out) and why much of what he does present on the Little Ice Age are unsubstantiated assertions and plain wrong.
    Ferrara continues making a rather poor fist of his following bold assertions in that he sets out a solar-caused Little Ice Age but then continues with an ocean-current-cause for the late 20th century warming. Had the warming of the late 20th century been caused by a wobble in ocean currents as Ferrara insists, such a wobble would be plainly evident within palaeoclimate records. There is no such wobble evident. (Indeed, the rationale behind the ‘Hockey Stick Graph’ [which denialists find so annoying] was to identify the size of such wobbles.) The wobbles through the Little Ice Age are far far too small to provide support for denialist Ferrara.
    And then by resorting to referencing the ranting lunacy of Christopher ‘swivel-eyed-loon’ Booker, Ferrara pretty much ensures his account is destined for the dustbin.
    Indeed Ferrara even attempts to emulate Booker’s stupidity in his closing paragraphs (which do seem to end rather abruptly), beginning with his assertion that “Human emissions of CO2 are only 4 to 5% of total global emissions, counting natural causes.”
    If you talk ‘gross’ emissions this “4 to 5%” is roughly correct but the important quantity is not ‘gross’ emissions but the ‘net’ emissions. Man-made ‘net’ emissions are running at about +4.8Gt(C)/year making mankind a net emiter. Natural ‘net’ emissions are running at something like -6.4Gt(C)/year making nature a net absorber, and of course making Ferrara’s final paragraphs no more than bare-face lies.

  22. 222

    V 216: BPL: Did they have an appreciable influence on temperature in that time?
    According to most climate scientists, no.

    BPL: Specify the starting and end dates you want and I’ll check it mathematically.

  23. 223
    CCHolley says:

    Victor @206

    According to most climate scientists, no. Some examples from the literature regarding the temperature rise during the 1st half of the 20th century.

    The question was whether CO2 had an influence on temperatures not “temperature rise”. Nice deflection by Victor. I don’t think most scientists wouldn’t answer “no” to that question.

    As stated many times, the period before 1940 remains highly uncertain due to a lack of good data. This study shows CO2 likely played a role, albeit perhaps modest-or maybe not.

    Simulation of Early 20th Century Global Warming

    Factors which could contribute to the early 20th century warming include increasing greenhouse gas concentrations, changing solar and volcanic activity, and internal variability of the coupled ocean-atmosphere system. The relative importance of each of these factors is not well known.

    Since the model includes no forcing from interdecadal variations of volcanic emissions or solar irradiance, this suggests that the observed early 20th century warming could have resulted from a combination of human-induced increases of atmospheric GHG and sulfate aerosols, along with internal variability of the ocean-atmosphere system.

    Assuming the simulated variability and model response to radiative forcing are realistic, the results of the present study demonstrate that the combination of greenhouse gas forcing, sulfate aerosols, and internal variability could have produced the early 20th century warming, although to do so would take an unusually large realization of internal variability. A more likely scenario for interpretation of the observed warming of the early 20th century might be a smaller (and therefore more likely) realization of internal variability coupled with additional external radiative forcings.

    However, if most of the warming of that period was the result of natural variability, it does not cast doubt on the role of CO2 in the current warming of the planet. “Natural variability” goes up and down — not just up. Natural variability cannot continue in one direction indefinitely because the heat associated with it is already in the system and is limited. This is basic physics. The current warming trend cannot be due to “natural variability” because at present both ocean temperatures and land temperatures are warming which requires an external forcing and land temperatures are warming faster than ocean temperatures which cannot occur with internal variability of the ocean-atmospheric system.

    If the period prior to 1940 was mostly due to “natural variation” then climate sensitivity to forcings must be higher than expected and CO2 warming will actually be worse than expected.

    Per the Swanson et al paper, Long-term natural variability and 20th century climate change referenced by Victor:

    Quantifying whether there is a large role for long-term natural variability in the climate system is important, as such variability could exacerbate or ameliorate the impact of climate change in the near future. Further, large magnitude variability may require revisiting the types and magnitudes of imposed forcings thought to be responsible for the observed 20th century climate trajectory. More ominously, a climate with large magnitude natural long-term variability in general is a climate very sensitive to imposed forcings, raising concerns about extreme impacts due to future climate change).

    As for the following period, from ca. 1940-ca. 1979, there was a period of abrupt cooling followed by a leveling off of temperatures. This “hiatus” is accepted by just about all climate scientists. Regardless of the cause, which some have attempted to explain as due to industrial aerosol cooling, one can’t accuse CO2 emissions of raising global temperatures during a period when there was no such rise.

    Once again the question wasn’t whether CO2 raised temperatures it was: Did they have an appreciable influence on temperature in that time?

    And the answer to that questioner the second period is an unequivocal, yes. Without the CO2 forcing, temperatures would have been much lower.

  24. 224
    JCH says:

    The early 20th century warming: Anomalies, causes,and consequences


    Longer records including recently digitized old records, together with reanalyses and large ensembles covering the entire20th century provide new and important insight into the climatic anomalies during the early 20th century. These are not onlyinteresting historically, but provide important evidence for events and anomalies that can occur and challenge climate modelsto explain or at least, sample them. Key events and anomalies include anomalously poor monsoon years around the turn ofthe century, the rapid Arctic warming into the 1920s, the Dust Bowl drought and heat waves in North America in the 1930s,and, approximately coincident with World War II, drought in Australia, and cold winters and hot summers in Europe in the1940s (see overview schematic in Figure 10). These anomalous events occurred during a period of strong global-scale warm-ing, which can be attributed to a combination of external forcing (particularly, greenhouse gas increases, combined with ahiatus in volcanic events) and internal decadal variability. The exact contribution of each factor to large-scale warmingremains uncertain, largely due to uncertainty in the role of aerosols in the cooling or stabilization of climate following themiddle of the 20th century.

  25. 225
    CCHolley says:

    Douglas @205

    I suggest you look at CITIZENS’ CLIMATE LOBBY

    Carbon Fee & Dividend Plan

    As for the science a good start would be this very recent RealClimate article.

    The Alsup Aftermath

    I would also suggest Spencer Weart’s: The Discovery of Global Warming

  26. 226
    mike says:

    Mayer Hillman feeling a little less-than-cheery about our collective situation:
    We’re doomed

    Ouch! It’s only 412 ppm. chill out. what is the worst that could happen?

    I hope some cooler heads will get in touch with Dr. Hillman and let him know that the reality is scary enough, this kind of presentation is of no value. Let’s just stick with reality which is scary enough, right?

    Is this guy, Mayer Hillman, an idiot or what?


  27. 227
    MA Rodger says:

    Victor the Troll @191,
    While the trail of nonsense you spin turns to attribution of early 20th century warming, which is hardily for the first time, I note you object to my comment @174 on account of yet more of your ridiculous reasoning.
    Whatever the vacuous twaddle you are attempting to explain as being some sort of AGW-busting truth, whether or not discussion of the flaws within it makes mention of CO2 is an irrelevance. These flaws which you are continually ignoring, they do not all involve CO2. So why is there a necessity to always mention CO2? Indeed, if it were a requirement to mention CO2, how many of your own twaddle-filled posts down this comment thread would have to be dismissed as “nothing to do with evidence regarding the alleged [sic] influence of CO2.”

    And it would be good to know what it is you are blathering on about, rather than having to guess.
    For a second time @191 (& a third @215) you cite some work-or-other by one of our hosts as being wrong (@156 “embarassing”, @191 “misleading to say the least,”). You made reference way-up-thread @81 to a graph of Church & White tidal gauge data presented in a Rahmstorf video presentation, so it is more Church & White than Rahmstorf, but is it what you mean? Also way-up-thread, @97 there was a link to Vermeer & Rahmstorf (2009). Perhaps that what you cite! Or is it Rahmstorf (2007) you are attempting to cite?
    And @156 you talk of Rahmstorf and “the embarrassing graph posted by Rahmstorf, which shows no sea level decline in the wake of 40 years of cooling.” But where is this “sea level decline” you talk of? In what data set does it appear? Or is it some denialist version of reality you are relying on? Or, possibly more likely, are you talking twaddle by confusing SL with SLR when you suggest we should see “a lowering of sea level”?
    Also for the record, talk of Hay et al (2015) upthread (presumably specifically referring to its Fig 1) would not be accessing “more accurate sources” as you wrongly assert @156.

    You blather-on yet your silly assertion that SLR somehow is incompatible with the influence of CO2 forcing on climate and your denial that CO2 is the main driver of recent temperature rise (including the +0.3ºC rise in global average temperature over the last 15 years that you are apparently in denial over): your blather is still at the stage of ‘Look! Wobbles here! No wobbles there!’ which was actually where we were 3½ years ago when you first pitched up here.

  28. 228

    Speaking as we were of climate forcings, this one may threaten to become significant:

    Hadn’t heard of this before. Potentially worrisome (or significant, at least), but with lots of work ahead to really know?

  29. 229
    CCHolley says:

    JCH @224

    The early 20th century warming: Anomalies, causes,and consequences

    Very good and very current paper.

    If Victor had any interest at all in the science he would read and study it. Not likely.

    Interesting excerpts:

    What caused the long-term warming from 1900 to 1950? The global temperature rise during the ETCW implies a change in the energy budget of the Earth’s atmosphere, which in turn suggests either an external forcing (volcanic, solar, greenhousegases, tropospheric aerosols), changes in clouds, or ocean heat release (Brönnimann, 2015b). Figure 4 shows that changes in several external forcings over the ETCW could be important, such as: a greenhouse gas increase, a small change in solar irradiance, and a reduction in stratospheric aerosols associated with reduced volcanic activity.

    Tropical volcanic eruptions, which were frequent in the 19th century (e.g., Tambora in 1815, and Krakatoa in 1883), became much rarer after the Santa Maria eruption of 1902 and the 1912 Katmai eruption. The relative muting of eruptions between this period and the eruption of Mount Agung in 1963/1964 thus implies a positive forcing, although volcanic emissions during this period are not well known (Neely III & Schmidt, 2016). Epoch analyses suggest that periods without volcanic forcing show warming as the climate relaxes back into a less volcanically cooled background state (Hegerl, Crowley,Baum, Kim, & Hyde, 2003; Schurer, Hegerl, Mann, Tett, & Phipps, 2013), and climate models show long-term climatechange in response to changes in the statistics of eruptions (Gregory, 2010; Schurer et al., 2014).

    The CO2 concentration increased from the beginning of industrialization in the 18th century, continuing to increase over the early 20th century and then accelerating more recently. Since CO2 forcing is logarithmic with concentration, early forcing is dis-proportionally important. Callendar (1938) already attributed the ETCW to increased CO2 concentration in the late 1930s. Some of the effect of CO2increases should have been counteracted by an increase in anthropogenic aerosols, which were important already over this period (Undorf, Bollasina, & Hegerl, 2018; Undorf, Polson, et al., 2018), and alone should have caused a sub-stantial cooling effect. However, even by 1900, reconstructions of hemispheric temperatures show evidence for a detectible warming driven by increases in greenhouse gases, particularly relative to slightly reduced CO2 during the Little Ice Age (Abramet al., 2016; Schurer et al., 2013) consistent with attribution of a substantial fraction of the ETCW in temperature reconstructions to greenhouse gas increases (Schurer et al., 2013). This is in addition to the warming over much of the 19th century that wasdriven by the recovery from an active volcanic period early in that century (Brönnimann & Krämer, 2016; Raible et al., 2016).

    The analysis is conducted by finding a combination of model derived time–space patterns of response to greenhouse gas, other anthropogenic and natural forcing (so-called fingerprints) that best matches the observations over the entire instrumental period (see Supporting information for more detail). The amplitude of each fingerprint that is consistent with data is estimated as a distribution of “scaling factors” (top panel in Figure 5), which when multiplied by the raw model results yields a distribution of the contribution of each forcing to the total observed anomaly (middle panel) and a residual variability notexplained by forcings (bottom panel; see also Figure 1, bottom panel and Hegerl & Zwiers, 2011 for more detail). The analysis indicates that both external forcing and internal climate variability contributed to the observed warming, with a strong green house warming contributing substantially to the ETCW, natural forcings contributing as well, and other anthropogenic forcing agents such as aerosols counteracting the warming. The natural signal is, at least in climate model simulations, largely due to a hiatus in volcanic eruptions (see Figure S4). Overall, about a half (40–54%;p> .8) of the global warming from 1901 to 1950 is estimated to have been forced. Forcings can, however, not fully explain the warming (indicated by the histogram of observed, positive, residual trends, Figure 5; compare also Figure 2 top panels with Figure S2). Note that the residual from a proxy-based global reconstruction is much smaller (Crowley et al., 2014), raising questions if the strong bias of observed data toward the Atlantic sector enhances the residual warming. This residual warming is, however, not extraordinary relative to samples of 50-year trends in climate models.

  30. 230
    Arvid says:

    226 mike

    here’s another really negative loon

    A growing cadre of climate glitterati ratcheting up its rhetoric to align with its rocketing emissions.

    Meanwhile journalists remain unwilling or ill equipped to call time on this catalogue of subterfuge.

    It’s twenty-seven years since the IPCC’s first report and a quarter of a century since the Rio Earth Summit, but still our carbon emissions are rising.

    Whether the latest depressing data signals that humanity was only ever set to be a destructive aberration is still not clear.
    (comment – aha, he’s prevaricating and hedging his bets the cheapskate lackig the courage of his convictions there)

    Indeed we may yet discover the moral fortitude to wrestle a decarbonised phoenix from the fossil-fuelled flames.

    But delivering such a fundamental transformation demands we reject rhetoric, dishonesty and fear and embrace the challenges and opportunities posed by clear thinking, integrity and courage.

    from Personal reflections on the 23rd COP in Bonn-Fiji – Nov. 2017
    Kevin Anderson (@KevinClimate), CEMUS. Uppsala University, Tyndall Centre, MACE. University of Manchester.

  31. 231
    Victor says:

    227 MA Rodger

    Your response is so full of assumptions, confusions, straw man arguments, nit picks and the like that I hardly know where to begin. I can only think of Alice’s red queen who must run full speed just to remain in the same place. I assume that by now you are totally out of breath. Keep it simple, sez I. (A word to the not-so-wise-as-he-thinks-he-is.)

    “But where is this “sea level decline” you talk of?” This one question speaks volumes for your inability to grasp even the most straightforward argument. Read my post one more time, slowly, to find your mistake.

  32. 232
    Victor says:

    223 CCHolley

    [F]or each accepted explanation of a phenomenon, there is always an infinite number of possible and more complex alternatives, because one can always burden failing explanations with ad hoc hypotheses to prevent them from being falsified . . . (

  33. 233

    Victor, please give me the start and end dates you want for the time period in question. I’ll check to see if CO2 correlates with temperature over that period. If it does, we have the likely causal sequence CO2 => temperature => sea level.

  34. 234
    MartinJB says:

    Victor (@231), one of the reasons you run into trouble here is that your arguments are often non-physical. Thus, when people who actually understand the physical model of how CO2, temperature and other phenomena (e.g. SLR) relate read your arguments, your arguments don’t necessarily make sense and can be misinterpreted.

    Take your (incorrect) argument about mid-century temperatures and SLR. You implied that the cooling should have led to a decline in sea level, and that the absence of a decline in sea levels shows a flaw in the model. That’s not actually correct (think about how long it takes changes in sea level to reach equilibrium with a new temperature), but I think I understand why you made the argument. It’s not at all surprising that someone might have misinterpreted your argument, since it is based on a fundamental misunderstanding of the physical model.

    (@232) “Adding” complexities that really exist is actually a good thing. Abandoning a good model because it is not perfect (none are) actually creates far more complexity, since you are forced to create non-existent physics that are inconsistent with physics as understood.

    You seem to have learned nothing of real substance since your first forays onto this board, with your fundamental misunderstanding of how regressions and correlation work in a complex physical system. All you’ve gathered are more nits to pick.

  35. 235
    JB says:

    The charade is nearly over:
    I’ve been saying for 20 years now that the IPCC overestimates climate sensitivity by about a factor of 2. Looks like that was right (ECS ~ 1.66K in the linked paper vs IPCC 3K). Time for the alarmist industry to get real jobs.

  36. 236
    mike says:

    Look at this! A backwards day. A drop in CO2 sats in yoy comparison. It’s a noisy number, but it’s still a startling thing to see. I have not looked back at 1998-2000 numbers to see how often this happened after that big EN event. My guess is that it did and that this downward number is not unique in the record and of course, finally, 412.63 ppm on April 26, 2017? That’s a number from hell.

    Daily CO2

    April 26, 2018: 411.32 ppm
    April 26, 2017: 412.63 ppm

    I would love to see a downward number in a week on week comparison. I have not seen that yet in the years I have been looking at these numbers.



  37. 237
    CCHolley says:

    Victor @232

    [F]or each accepted explanation of a phenomenon, there is always an infinite number of possible and more complex alternatives, because one can always burden failing explanations with ad hoc hypotheses to prevent them from being falsified . . .

    lol, Victor cannot dispute the actual science so he somehow invokes Occam’s Razor and also claims the science is “ad hoc”. Of course he does not explain how Occam’s Razor actually applies in this situation or which theory is least complex while still fitting the the evidence and remains within the possibilities of physical laws. I would suspect Victor is actually clueless when it comes to the actual meaning and application of Occam’s Razor. As for “ad hoc” he does not explain how attempts at explaining these periods using our knowledge of how climate works is somehow compensating for weaknesses in climatic theory.

    None of this is a surprise because none of the discourse by Victor has ever been in the spirit of learning, rather it is to arrogantly proclaim superior knowledge in areas for which the evidence actually shows he has little or no knowledge or expertise. Repeatedly.

    Once again he never makes any attempt to understand the science and what the evidence actually tells us. He would rather call legitimate science “ad hoc” instead of attempting to understand it. The science and evidence that is presented to show the stupidity of his arguments is simply just disregarded and ignored. Yet Victor thinks he makes strong arguments. What a deluded nut case.

    This recent article in Skeptical Climate: The Denial Personality fits Victor to a tee, except he is completely clueless as to any aspect of the science.

  38. 238
    nigelj says:

    Victor @232 provides a link to occams razor which says “Occam’s razor is the problem-solving principle that, when presented with competing hypothetical answers to a problem, one should select the one that makes the fewest assumptions.”

    We have competing hypothetical answers to why the climate has warmed since the 1970s (volcanic activity, cosmic rays, solar activity, etc, and CO2 emissions) and CO2 emissions involves making the fewest assumptions, and is the simplest most cogent evidence based explanation, and the most consistent with the full range of evidence but Victor just can’t work it out, because he doesn’t understand anything he reads.

  39. 239
    Arek says:

    In response to questions by Douglas some suggestions were made @158

    Douglas subsequently made comments about what he saw as the barriers to a 3rd political centrist party especially in the US. however the suggestions I made were meant to be considered as an integrated whole and not as a list of options.

    Each nation’s situations and systems are different but the core issue is the same. The dominant parties no longer represent the core values and needs of a majority of voters or the people, even those who still Vote for them anyway.

    3rd parties specifically are hollowing out support for major parties already. some US centric examples:

    In the 16 states and DC where comparable data is available, Independent voter enrollment surged by 28.4% since June 2008. By contrast, Democratic and Republican enrollment grew by 6.6% and 3.6%, respectively.

    Independent enrollment in Colorado, Florida, Iowa, Nevada, New Hampshire, North Carolina, and Pennsylvania jumped 34.5% between June 2008 and June 2016. Democratic enrollment—up 3.7%—and Republican enrollment—up 6.6%—barely budged by comparison.

  40. 240
    MA Rodger says:

    Victor the Troll @231.
    I appreiciate you are mind-numbingly stupid but in posing you a few very simple questions @227 I provided you the opportunity to indicate what you can and cannot understand and to respond accordingly. My mistake. All you can manage is a mind-numbingly-stupid non-answer.
    Of course I can re-visit your comment @156 as you ask and set out succinctly what you say there on this “sea level decline” you mention. You will probably still be oblivious to the stupidity you achieve but setting out your comment succinctly will demonstrate to others how very foolish your comments are.

    @156 within a single paragraph:-
    ♥ You make bold assumptions about an SLR study you evidently have not read.
    ♥ You refer to “the embarrassing graph posted by Rahmstorf” although you fail to indicate properly to which graph you refer (not for the first time).
    ♥ You then speculate about this “sea level decline,” seemingly assuming it would/should be apparent in the SLR study you evidently haven’t read.
    ♥ You suggest that “sea level decline” would be a logical result from “a long period of atmospheric cooling” but fail to link this suggestion to any specified time period or any specific evidence within global temperature or SL records.
    ♥ You then describe the same time period as being when “CO2 emissions, which were skyrocketing while global temperatures either fell or remained steady. Over 40 years!” yet this unspecified “over 40 years” is unlikely to be characterised as “a long period of atmospheric cooling” if “global temperatures either fell or remained steady.” And it is probably not 40 years in length.

    Of course we all make mistakes and errors. But Victor you do manage to be perpetually mistaken and in error. Well done you!! That is quite an achievement.

  41. 241
    nigelj says:

    JB @235

    “The charade is nearly over:

    I’ve been saying for 20 years now that the IPCC overestimates climate sensitivity by about a factor of 2. Looks like that was right (ECS ~ 1.66K in the linked paper vs IPCC 3K). Time for the alarmist industry to get real jobs.”

    Seems ridiculous to assume one new paper is correct. Especially when you have have this recent research:

    “One of the most important parameters in climate science is the equilibrium climate sensitivity (ECS). Estimates of this quantity based on 20th-century observations suggest low values of ECS (below 2 °C). We show that these calculations may be significantly in error. Together with other recent work on this problem, it seems probable that the ECS is larger than suggested by the 20th-century observations.”

    So I think I will wait and see what the next IPCC report concludes, rather than jumping to concusions, like you clearly do. I am not climate expert, but it seems to me unwise to base conclusions purely on some historical time frame unless its really long, hundreds of years.

  42. 242
    CCHolley says:

    I’ve been saying for 20 years now that the IPCC overestimates climate sensitivity by about a factor of 2. Looks like that was right (ECS ~ 1.66K in the linked paper vs IPCC 3K). Time for the alarmist industry to get real jobs.

    I wouldn’t be so sure.

    New Lewis and Curry paper is out! Unfortunately for them, it’s already shown to be wrong! Our recent paper showed that the methodology produces answers that can deviate significantly from reality. … 1/

  43. 243
    sidd says:

    In paleo reconstruction (this interglacial) models, do any use Ruddiman’s ideas ?


  44. 244
    MA Rodger says:

    There is an article in the Economist ‘The methane mystery: Scientists struggle to explain a worrying rise in atmospheric methane’ that should give the skyrocketeers some food for thought, although I would suggest they take due note of the statement “But methane-rich Siberian air shows no sign of rising any faster than the rest of the world.”

  45. 245
    Ray Ladbury says:

    Occam’s Razor is merely one of many heuristics that apply to scientific theories–and the statement you give is merely one statement. My personal favorite is Akaike’s Information Criterion, which is not ad hoc, but related to a fundamental quantity in statistics. And, sure enough, Occam’s Razor is more applicable to statistical models than it is to physics-based models.

    A more important heuristic is the predictive power of a theory–how many verified predictions has it made. Here, climate models have a long, and successful track record.

    Fortunately, the criterion for scientific success is not that it be understandable by imbeciles.

  46. 246

    I recently pointed out that the idea that cutting fossil fuels would hurt the poor has lost any validity it may have had, citing renewable energy cost parity (or even cost advantage), as well as the externalized costs of fossil fuel use.

    Now there’s news of a study doing an apparently pretty rigorous estimate of the Chinese case. A group out of MIT finds that if China enforces existing policy, reaching peak emissions no later than 2030, the result will be nearly 100,000 premature deaths avoided, several hundred billion dollars of economic savings, and a net benefit/cost ratio of four to one.

    A more stringent policy would have greater benefits.

  47. 247
    mike says:

    March CO2

    March 2018: 409.46 ppm
    March 2017: 407.18 ppm

    2.28 ppm increase yoy comparison.

    what can you say, it’s an upward-sticky number.

    Should be fine, no reason to worry. Same with methane: No worries, doing great. Just ask Victor if you need confirmation.

    Don’t feed the trolls. Just tease them occasionally and laugh them off.



  48. 248
    Victor says:

    238 nigelj says:

    nj: Victor @232 provides a link to occams razor which says “Occam’s razor is the problem-solving principle that, when presented with competing hypothetical answers to a problem, one should select the one that makes the fewest assumptions.”

    We have competing hypothetical answers to why the climate has warmed since the 1970s (volcanic activity, cosmic rays, solar activity, etc, and CO2 emissions) and CO2 emissions involves making the fewest assumptions, and is the simplest most cogent evidence based explanation, and the most consistent with the full range of evidence but Victor just can’t work it out, because he doesn’t understand anything he reads.

    V: Glad you brought up this issue, nigel, which does seem reasonable, up to a point. From my book:

    “We’ve seen, from the tutorial we’ve been examining [], that the physics of climate change, regardless of how sound each step in the process might seem, is far too complex to satisfy Occam’s Razor — we have no way of knowing whether a simpler explanation might account equally well or better for the known physical interactions. And if the physics of climate change as outlined in this tutorial is too complex to satisfy Occam’s Razor, then what is? Looks to me like the much simpler argument that CO2 is a greenhouse gas; greenhouse gases enhance atmospheric warming; enormous amounts of CO2 are now being emitted via the burning of fossil fuels; and according to various measurements, the temperature of the atmosphere appears to be steadily increasing as a result. Simple. Easy to understand. And in fact the most commonly invoked sequence when the issue is argued publicly.

    Who needs all that complicated physics when the burning of fossil fuels is such an obvious factor in the warming of the planet? So obvious, and so simple, that even many climate skeptics are willing to accept the argument — up to a point. The physics is necessary to justify the hypothesis scientifically, but need not be part of the argument itself, which can be, and almost always is, made in much simpler terms. So what is wrong? Why do I continue to be a skeptic if the mainstream view satisfies good old Occam’s Razor?”

    What’s missing in many definitions of Occam’s Razor is the all important notion of “necessity.” Entities should not be multiplied beyond what is necessary. Necessary, that is, in order to account for ALL the evidence. Contrary to popular opinion, it’s not the simplest explanation, but the simplest explanation capable of accounting for ALL the evidence, that is necessary to satisfy Occam’s Razor. In my book I make the point that “climate change” advocates have focused on the simplicity of the basic CO2 forcing argument while ignoring all the many pieces of evidence, as outlined in the book, that it is unable to account for. Thus a simplistic notion of “simplicity” has misled both scientists and laymen into assuming that CO2 emissions are causing out of control global warming despite the preponderance of evidence to the contrary.

    Of course climate scientists are well aware of the problem, which is why we see so many studies directed almost exclusively to explaining away at least some of the discrepancies. In doing so, however, they add complications of the sort that Occam’s Razor was deliberately constructed to discourage.

    Once again, from my book:

    “In order to account for the discrepancy represented by the “hiatus,” there has been a wide variety of different “explanations.” But once again Occam’s Razor presents a barrier:
    “. . . [F]or each accepted explanation of a phenomenon, there is always an infinite number of possible and more complex alternatives, because one can always burden failing explanations with ad hoc hypotheses to prevent them from being falsified . . .
    Put another way, any new, and even more complex, theory can still possibly be true. For example, if an individual makes supernatural claims that Leprechauns were responsible for breaking a vase, the simpler explanation would be that he is mistaken, but ongoing ad hoc justifications (e.g. “and that’s not me on the film; they tampered with that, too”) successfully prevent outright falsification. This endless supply of elaborate competing explanations, called saving hypotheses, cannot be ruled out — but by using Occam’s Razor. (Occam’s Razor – Wikipedia)”

    In the field of climate change there have been no shortage of ad hoc “saving hypotheses”; however, according to Occam, “plurality should not be posited without necessity,” and, as with the Ptolemaic epicycles, that is precisely what the climate scientists are doing. Which is not to say that some sort of formula that satisfies Occam isn’t possible — but its necessity as a fully adequate explanation would have to be demonstrated, and that has, as yet, not been done. In fact most if not all of the posited explanations look very much like arbitrary efforts to explain away the difficulties by filling in certain gaps with ad hoc, retrospectively derived, models.”

  49. 249
    Victor says:

    245 Ray Ladbury says:

    “. . . And, sure enough, Occam’s Razor is more applicable to statistical models than it is to physics-based models.”

    Occam’s Razor is a fundamental principle applicable to scientific research of any sort, employing any type of methodology, statistical or otherwise. You are betraying your ignorance.

    “A more important heuristic is the predictive power of a theory–how many verified predictions has it made. Here, climate models have a long, and successful track record.”

    So did the Ptolemaic epicycles. It’s always possible to fine-tune one’s predictions to get the desired results (as did the school of Ptolemy) or come up with “corrections,” “data adjustments,” etc. that could account for discrepancies (as did the school of Ptolemy), a procedure that has become routine among climate “scientists.”

    >Fortunately, the criterion for scientific success is not that it be understandable by imbeciles.


  50. 250
    nigelj says:

    Keven McKinney @246, adding to your comments about cutting fossil fuels not hurting the poor, and reductions in health care costs with less use of fossil fuel use in China, this is a pretty astonishing article:

    “The missing maths: the human cost of fossil fuels. We should account for the costs of disease and death from fossil fuel pollution in climate change policies”

    “A recent study estimates that the health co-benefits from air pollution reductions would outweigh the mitigation costs of staying below 2°C by 140–250% globally (!)

    “Historical evidence paints a similar picture. The EPA estimates that the U.S. Clean Air Amendments cost $65bn to implement, but will have yielded a benefit of almost $2tn by 2020 in avoided health costs.”