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Koonin’s case for yet another review of climate science

We watch long YouTube videos so you don’t have to.

In the seemingly endless deliberations on whether there should be a ‘red team’ exercise to review various climate science reports, Scott Waldman reported last week that the original architect of the idea, Steve Koonin, had given a talk on touching on the topic at Purdue University in Indiana last month. Since the talk is online, I thought it might be worth a viewing.

[Spoiler alert. It wasn’t].

The red team issue came up a few times. Notably Koonin says at one point in the Q and A:

The reports are right. But obviously I would not be pushing a red team exercise unless I thought there were misleading crucial aspects of the reports.


But in over an hour of talking, he doesn’t ever really say what they are. Instead, there are more than a few fallacious arguments, some outright errors, some secondhand misdirection, a scattering of dubious assumptions and a couple of very odd contradictions. I cannot find a single instance of him disagreeing with an actual statement in the reports.

First, the fallacies

Three examples:

Until you explain variability on all the scales relevant to the alleged human warming, you haven’t really nailed it down.


Nope. This is basically claiming that until you know everything (an impossible task), you know nothing.

33:00. Apparently, Koonin “doesn’t think” rapid sea level rise is going to happen in the future because it hasn’t happened over the last 100 years at the Battery in NYC.


35:40. Koonin skips his slide on why Arctic sea ice trends aren’t anything to worry about, but his point was going to be that people noticed warming in the Arctic in 1923. This is of course another fallacious argument (and we’ve dealt with it before).

Contradiction Central

There are two glaring sets of contradictions in the talk, first, involving attribution of past change and secondly, his stance on normative judgements in discussing science. Starting around 7:29 he discusses attribution of recent trends and states:

You had better have [natural influences] under control before you can attribute what you see to human influences.

This is fair enough (assuming he means that one should have a good handle on natural variability rather than ‘controlling’ it), and one might read this as a statement that attribution is complex and deserves careful attention – an opinion with which I fully concur. But this is illustrated with the most useless kind of pop attribution. He makes a blanket statement that any changes prior to 1950 must be purely ‘natural’ without any analysis at all (a stance completely at odds with the literature, for instance, Hegerl et al., 2018), and supports it with an uncredited graph from, of all people, Bob Tisdale, a frequent blogger at WUWT, showing running 30 year trends of the (now obsolete) HadCRUT3 data. That’s an interesting choice of metric because it is the longest trend period you can use that allows the ~1940 rise to almost match the more recent decades. With 35 year, or 40 year, or 50 year or 60 year trends, the exceptional nature of the recent change is obvious.

His second contradiction concerns his statements about normative values. He, of course, claims to make no normative statements, while implying others (unnamed) are perverting their science to do so. And yet, not only is his talk filled with his opinions, he has a remarkably different approach to the climate science results than to the results from economic modeling. For the former, he is hyper-critical (mostly without any valid cited reasons), while for the latter he appears naively credulous. This, at best, is incoherent, since the economic projections are rife with embedded normative values.

For instance, he uses a standard contrarian argument that future damages associated climate change will be a small fraction of the expected economic growth and therefore do not need to be mitigated. But the models that produce that result simply assume that no amount of damage from climate change can effect the exogenous growth rate. Additionally, they assume that damages themselves are simply proportional to the square of the temperature anomaly. You can judge how credible these assumptions really are. Of course, if we are to be ridiculously better off in the future without any effort, then the estimated costs of mitigation (also a few % of GDP) are also irrelevant.

Koonin gives his summary around 47:00, after spending a fair bit of time correctly describing the size of the challenge involved in stabilizing climate. But then he just shrugs and assumes that it is too big to ever be dealt with. This is not a conclusion that “just comes from the numbers”. He clearly has a normative preference for adaptation (seemingly oblivious to the point that it is very hard and very costly to adapt to a continuously changing, and even accelerating situation). Whether or not mitigation will be too hard, it is undoubtedly a normative decision to give up trying.

Errors galore

Some of these are trivial, some are more consequential, but all are illustrative of someone who is not well-versed in the topic.

At 14:40, he claims that climate models take time steps of 6 hours. It would be a little hard to resolve the diurnal cycle with that. The correct value is more like 15 to 30 min for the column physics, and more like 2 or 3 minutes for the advection routines. Curiously, even the slide he is talking to says this.

18:45. he says that Figure 9.8 in IPCC AR4 (2013) was ‘misleading’ because it showed anomaly temperatures alongside the range of absolute mean global values. This is odd. If the sensitivity of the model is not dependent on the base state, this is a good result.

20:34. he claims that the CMIP5 models were tuned to 20th Century trends, which is why without anthropogenic forcings they show no trend. This makes no sense at all. First, it is just untrue that all the models were tuned on the trends. And second, if there is no big trend in the natural forcings, you just aren’t going to get a big long term trend in the response. Nothing to do with tuning.

21:06 Another graphic borrowed from Bob Tisdale. This one makes the classic error of confusing the forced trend (as estimated from the mean of model ensemble) with the actual trend (which includes the actual forced trend and internal variability). For someone who claims to be interested in how internal variability is represented in models, that’s an odd lacuna.

26:00. His slide 25 is just BS from start to finish. Note there are no actual quotes from any specific case – everything is a strawman argument.

28:05. He quotes me! This is not an actual error, but I find it funny that my views on how the media treats extremes (at least in 2013) are worthy of inclusion, but not, say, my views on climate modeling or attribution (you know, my job).

31:00. Satellite records of sea level rise (since 1992) “are commensurate” with the tide gauge estimates (roughly 2mm/yr). Sure, but Koonin mysteriously neglects to mention they are 50% higher than the long term trend from those gauges. Also missing from his commentary on longer term records is that even the modern tide gauge-derived rate is more than twice the Holocene trends since 6000 BP (see for instance, Ashe et al., 2018).

34:10 “If you get all your climate information from watching CNN or reading the New York Times or Washington Post [the data on hurricanes] is a surprising statement”. Apparently, these outlets report on hurricane trends so frequently and so erroneously that no reference to them actually doing so is needed. Ok then.

50:02. “I would do more when the signal has come out of the noise, which it has not yet”. This is complete rubbish. The signals of temperature change, sea level, sea ice loss, intense precipitation, heat waves, phenology, permafrost loss, Greenland melt, ocean heat content etc. have all clearly ‘come out of the noise’. What is he really waiting for?

Is there anything new here?

This is what I don’t really understand: There is absolutely nothing new here. Every argument, point, and even some graphics, are old, stale, and previously rebunked. These points could have been made (and undoubtedly were) in official reviews of assessment reports going back years. The people making these points have undoubtedly been told this and shown responses. In Koonin’s case, I know this for a fact (for instance). And yet, they persist. There is no development of the arguments, no counter-points, no constructive back and forth, just the same arguments that they appear to have thought up once and never examined.

Personally, I like taking on smart criticisms. They help hone the science, clarify the arguments and point to areas of needed research. But there isn’t a single thing here worth taking on.

Two thumbs down.


  1. G.C. Hegerl, S. Brönnimann, A. Schurer, and T. Cowan, "The early 20th century warming: Anomalies, causes, and consequences", Wiley Interdisciplinary Reviews: Climate Change, vol. 9, pp. e522, 2018.

61 Responses to “Koonin’s case for yet another review of climate science”

  1. 51
    MA Rodger says:

    Keith Woollard @46,
    It is bad enough that we have the cloth-eared nonense from Dan DaSilva entered on these threads but for you to say “So DDS @ 17 was correct in his statement” is something that needs challenging.
    Dan DaSilva @17 continues from Dan DaSilva @12, a comment that manages to present multiple errors.
    The “30-year average chart” is presumably the blinky chart above in the OP which has a 30 year version. It does not show “the temperature rise from 1895-1930” or “the temperature rise from 1955-2010” as it obviously plots trends – the rate of change in temperature in ºC/dec. (For the record, the 30-year average in GISTEMP rose 0.23ºC 1895-1950 (a rate of 0.042ºC/dec) and 1955-2004 rose 0.58ºC (a rate of 0.118ºC/dec). The reason the 1955-2004 temperature rise is calculatedis because the data required to calculate the 30-year average rise 1955-2010 will only be available in 2025.)
    The blinky chart in the OP presumably calculates trends using OLS. What it shows is the trend rose slightly more over the period 1955-2004 (+0.23ºC/dec) than the period 1895-1931 (+0.21ºC/dec), so their relative magnitude cites @12 is the wrong way round: even the values cited from the graph (+0.12 & +0.14) are flat wrong.
    So the entirety of #12 is wrong and #17 continues in the same vein.
    The assertion that “Temperature reconstructions proxies show no indication of the temperature rise form 1895-1930 (see hockey stick)” is a little strange. Of course the hockey stick shows the 1895-1930 rise. They all do!! How else would they be calibrated?
    The assertion that “the rise was just as large as the current rise from 1955-2010 (according to the 30-year chart of this article)” has already been shown to be entirely false.
    The assertion that “1895-1930 warming has not been explained” is untrue. While it remains true to say that a complete explanation is work-in-progress, that work-in-progress does explain the warming and within that, half the warming has already been explained entirely.
    And the assertion that asking the question “Could it be the same reason as the current warming?” is “somehow an affront to science” is only correct if the enquiry is not coupled with attention to the resulting answer.
    So Keith Wollard @46, if DDS was correct “in his statement”, which bit of “in his statement” were you referring to?

  2. 52
    Keith Woollard says:

    MA @ 51,

    I feel it is clear which bit. DDS made a number of statements. Windchaser asked for a citation for one. I provided that citation. Pretty damn simple in my opinion.

    This tribal mentality is so counterproductive.

  3. 53

    NS 29: there is no 333 W/m^2 GHG energy up/down/”back” loop to “warm” the earth. (TFK_bams09)

    BPL: The back-radiation can be easily measured with a device called a pyrgeometer, available since at least the 1950s. Or you can just point a camera with infrared film toward the night sky, or during the daytime sky as long as you don’t point it toward the sky. So any theoretical argument against the existence of atmospheric back-radiation is out of court from the beginning; you might as well argue against the existence of sunlight.

    “When you see a rainbow, you don’t stop to argue the laws of optics. There it is, in the sky.” -Robert A. Heinlein, 1958.

  4. 54

    Sorry, I meant, “as long as you don’t point it toward the sun,” of course. That would overexpose the IR film.

  5. 55
    MA Rodger says:

    Keith Woollard @52,

    Thank you for clarifying the situation, in that it is now a little clearer but I fear still far from clear.

    My take on it is this:-
    We have Dan DaSilva @12&17 presenting a pile of eye-bulgingly silly nonsense within which he states “Yet many climate scientists make the claim that the current rise is UNPRECEDENTED for the last 10,000 years.”
    In reply we have Windchasers @27 asking “Mind providing a citation for this (statement)?” which then leads to your intervention @36 where you describe your search for such a citation to show “many climate scientists make the claim.” But you fail to find such a citation. All you find is ‘hints’. “There are certainly many other parts of the document that hint at the same thing without actually claiming it.”
    Yet then I read Keith Woollard @46 stating “Regardless, I am still giving the citation (even though it isn’t exactly the right wording) that Windchaser @27 is looking for. So DDS @ 17 was correct in his statement.”
    But you didn’t find a citation. So surely that would suggest (concerning this isolated assertion about there being such a “citation”) that Dan DaSilva @17 was incorrect!!!

    Of course, there may well be such a citation.
    This first citation I present does involve the “many climate scientists” but perhaps not enough “years.” The Union of Concerned Scientsts must include “many scientists” and here we have then citing the IPCC AR5 SPM Section B. Observations in the Climate System which is authored by “many climate scientists,” begins saying:-

    “Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased.” [My bold]

    But we are here looking for ten-or-more ‘millennia’ while the IPCC quote could mean no more than two millenia, and that for just part of its ‘unprecedentedness.’ So is it “millennia” for ☻ Warming atmosphere, ☻ Warming oceans, ☻ Shrinking snow, ☻ Sea level or ☻ GHGs?

    ☻ In reverse order, for GHG levels, it is far more than just a few millennia. The IPCC AR5 Synthsis Report SPM puts the level of GHGs causing AGW to be “unprecedented in at least the last 800,000 years.” And it’s unprecedented for the rate of change as well – “The extreme speed at which carbon dioxide concentrations are increasing is unprecedented. An increase of 10 parts per million might have needed 1,000 years or more to come to pass during ancient climate change events.” (Robert Munroe, Scripps Inst, 2013.)
    ☻ Sea level is also “millennia” but probably not as long as “10,000 years.” Lambeck et al (2014) finds SLR dropped to not-much-more-than 1mm/year from 6,700yr bp and well below 1mm/yr from 4,200yr bp. Prior to that they find SLR running at 6mm/yr at 8,000yr bp and 13mm/yr at 9,000yr bp – thus the claim that SLR is faster than at any time for 6,000 years. And as this is all upward sea level change, global sea level is higher than it has been for 100,000 years.
    ☻ As SLR through the final stages of the deglaciation were driven by the melting of left-over ice rather than warming, the SLR appears a good proxy for ice & snow melt. More directly, the NSIDC do use the word “unprecedented” and “5,000 years”, but again that isn’t a full Banzai!!
    ☻ The warming oceans do show rates of warming “unprecedented for the last 10,000 years” according to Braddock Linsley of Columbia University and a co-author of Rosenthal et al (2013) ‘Pacific Ocean Heat Content During the Past 10,000 Years’. Apparently, “in a reconstruction of Pacific Ocean temperatures in the last 10,000 years, [these] researchers have found that its middle depths have warmed 15 times faster in the last 60 years than they did during apparent natural warming cycles in the previous 10,000” [years]. Fifteen-times faster – that’s pretty impressive!!
    And also regarding the ‘impressive’ rate of change in our oceans, “The current rate of ocean acidification appears unprecedented at least over the last 300 million years,” according to a WMO statement.
    ☻ Finally, to the actual issue discussed by Dan DeSilva, the rate of increase in surface temperature (which is greatly modulated by ocean temperature). This does show an increase unprecedented in the last 5,000 years, according to Marcott et al (2013), “Global temperature, therefore, has risen from near the coldest to the warmest levels of the Holocene within the past century, reversing the long-term cooling trend that began ~5000 yr B.P.” And this study shows nothing like the last century’s warming in the 5,000 years prior to 5,000yr bp, so I think a Banzai!!! is in order.
    And of course, that rate of warming continues apace. So 6 years on from this 2013 paper, it is likely that we have now topped the Holocene Thermal Maximum.

  6. 56
    Romain says:

    Wind chaser, 27
    You will find a few claims of unprecedented warming in 10,000+ years on this very RC site, but many RC commenters are not scientists.
    I took part in the discussion Keith Woollard mention. Because this claim was made and I challenged it. Worth a read.

    Otherwise, by googling it, i came across Joe Romm.

    But yes I think you are right, it does not look that this claim is made by “many climate scientists”. And that’s good, because it is a very bold claim.

  7. 57

    A plus-one to BPL’s post at #53, in which he points out that down-welling IR is measured all the time, and can easily be demonstrated by anyone with a brain, mobility, and a few dollars to spend. I’d only add that DWR has been measured, on and off at least, since the early years of the 19th century–with measurements even preceding Fourier’s work on the Terrestrial heat budget, done in the 1820s.

    See, for instance, my article on William Wells and his Rumford Medal-winning paper, “On Dew”:

    I recap Wells, and trace some subsequent research on the topic here:

    Heck, it’s even got pictures of pyrgeometers!

  8. 58
    Dan DaSilva says:

    After reading the posts here, reviewing google searches, and the hockey stick graphs I have come to the regrettable conclusion that 10,000 years is wrong and the time period should have been 1,000 years. Also the phrase “some climate scientists” should be substituted for “many climate scientists”.
    As a form of self disipline, I will refrain from comments for a period of 1 month.

  9. 59
    MA Rodger says:

    The poor old Red Team appear to have been led away for a spell in the long grass while the 2020 Presidential Campaigns take centre stage, according to this E&E News report. That denialist plans to stifle AGW science have been poleaxed by real-politic is good to see. In past years in UK I encountered many politicians shying away from supporting calls to act properly on the findings of AGW science for fear of losing votes and possibly their seats to denialist right-wing opponents. So it is good to see the impact of real-politic is now acting the other way.

  10. 60
    Hank Roberts says:

    Sorry to misplace this, the appropriate thread appears not to be taking comments.

    Is it possible to enjoy both economic growth and environmental sustainability?

    This question is a matter of fierce political debate between green growth and post-growth advocates. Considering what is at stake, a careful assessment to determine whether the scientific foundations behind this decoupling hypothesis are robust or not is needed.

    This report reviews the empirical and theoretical literature to assess the validity of this hypothesis. The conclusion is both overwhelmingly clear and sobering: not only is there no empirical evidence supporting the existence of a decoupling of economic growth from environmental pressures on anywhere near the scale needed to deal with environmental breakdown, but also, and perhaps more importantly, such decoupling appears unlikely to happen in the future.

    ‘Decoupling debunked’ highlights the need for the rethinking of green growth policies and to complement efficiency with sufficiency.

  11. 61
    Al Bundy says:

    The problem is that “economic growth” is used as a metric for “human welfare” when there is little linkage between the two. If you do things more efficiently you degrade economic output while increasing human welfare. Laborism focuses on utility and longevity. Capitalism focuses in creating the most landfill.

    You want a logical answer, use logical terms – and logic is anathma to GOPpers.

    Please try to use logical definitions instead of drinking the always wrong’s definitional Kool-aid

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