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.

koonins case for yet another review of climate science - Koonin’s case for yet another review of climate science

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).

gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw== - Koonin’s case for yet another review of climate science

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.

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