Off for a couple of weeks

I’m leaving for a meeting early tomorrow morning and then heading out on holiday as soon as I’m back, so posting – from me, at least – will probably be light for a couple of weeks. To be quite honest, I’m somewhat at a loss for things to say. I have some thoughts about Michael Tobis’ recent posts, but haven’t even started drafting anything and, once I have, I want to run it past Michael before I do post it.

I’m feeling a little worn out, so am looking forward to a couple of weeks away (the first week is a work trip, admittedly). I’m also finding myself more and more discouraged by the level of discourse. I’ve been observing some of the conflict between those who support nuclear and those who support renewables. Mostly more heat than light, in my view. I had a brief discussion with someone who is pro-nuclear who seems to think that those who are anti-nuclear are evil, and we also recently had a case of someone refering to those who support nuclear as deniers.

I’ve also been slightly discouraged by the whole saga surrounding David Wallace-Wells article (I’ve linked to the annotated version, so you can check his sources and how he has responded to the criticism). I think there were aspects deserving of criticism, but I also think he was trying to do something interesting; highlight the possible severe outcomes if we do end up continuing to emit CO₂ into the atmosphere. I might disagree with how he framed the issue, but I still think it is an aspect that we do need to consider. It’s also led to a lot of discussion, which is itself good. Some of the criticism could – in my view – have been a bit more charitable.

To be fair, some of the criticism of those who approach this from an alternative perspective might also be lacking in charity (and this may include some of my criticism too, to be honest) and I’m starting to be a little concerned that there is a fairly narrow region of parameter space that is regarded as acceptable. I’m somewhat worried that I’ve allowed myself to be too influenced by this; I think I may be too careful and cautious about what I say. As a scientist this can be a good thing; try to only say what you think you can justifiably defend.

On the other hand, this is a blog, not a scientific publication. There are aspects of this topic that are worth exploring, even if they are uncomfortable and not everyone agrees about whether to do so, or not. Avoiding these thing can mean not having to deal with some of the more vitriolic responses, but it does feel a little safe and maybe a bit cowardly. I’m going to have to have to give this a bit more thought. Anyway, it’s time for dinner, but then I need to pack and try to get an early night.

Doomsday scenarios

There’s been a bit of a furore over an article called The Uninhabitable Earth by David Wallace-Wells. The goal was clearly to investigate some of the extreme scenarios, but – unfortunately – the article got a number of things wrong and was rightly criticised in this Climate Feeback response.

However, I think this is all rather unfortunate, as I do think we should be able to discuss the more extreme scenarios; it’s a pity that the article wasn’t more careful when doing so. Although much of the criticism was indeed valid, I do think that some was a little uncharitable, given that the intent of the article wasn’t specifically to be alarmist, but was to try and present some of the more extreme possible outcomes. In that vein, David Roberts has a response that is worth reading.

Okay, I’m struggling to put together a post that is coherent, so I’ll try to make a point about presenting doomsday scenarios. I think it’s fine for them to be discussed, but my view is similar to what Joe Romm presents here. A key point is that we are doing this to ourselves. This isn’t really the same as, for example, the possibility of an asteroid strike in which we’re trying to determine how big it is and whether it’s going to strike the Earth, or not. In the context of climate change, the possibility of these extreme scenarios depends entirely on what we do; we essentially have complete control. Climate change is happening because we’re emitting CO₂ into the atmosphere and the impact will depend on how much we choose to emit.

Of course, this doesn’t mean that dealing with this is easy; there are also potentially severe scenarios associated with what we might do to avoid the impacts of climate change. However, that still doesn’t change that we are in control and we can choose – if we wish – to minimise the possibility of severe climate impacts. So, I think discussing these severe scenarios is fine, but I do think it’s important to recognise that these will only materialise if we really do choose to simply continue emitting increasing amounts of CO₂ into the atmosphere.

Maybe there will be some point where we’ve really left things so late that there will be little we can do to avoid some very severe/catastrophic outcomes, but we’re certainly not there yet and I think it is important to make this clear.

Reconciling climate sensitivity estimates – part III, or IV?

I mentioned in a recent post that there was a new paper that claims to reconciles climate sensitivity estimates. The basic issue is that observationally-based climate sensitivity estimates have a range of about 1.5^oC to about 3^oC, while climate model estimates tend to range from about 2^oC to about 4.5^oC. However, if you use climate models to estimate something equivalent to an observationally-based climate sensitivity, you get something consistent with these estimates.

However, to the surprise of noone, Nic Lewis has already claimed that their analysis is wrong. His argument appears to be that they made an error (I don’t know if they have) and that the equivalent observationally-based estimates you would get from climate models is higher than they claim. Also Nic Lewis claims that the range for the actual observationally-based estimates is lower than they claimed in the paper. Therefore their claim that these different estimates have been reconciled is wrong.

I don’t know if Nic Lewis has really found an error. That it would appear impossible to publish a paper that reconciles these climate sensitivity estimates without Nic Lewis claiming to have found some kind of fundamental error might suggest caution. However, based on some tweets from Kyle Armour, even if there is an error, it would seem not as obvious as Nic is claiming (not the first time that has happened). Since, however, I don’t have the time to really work out whether he is right, wrong, or somewhere inbetween, I thought I would make some general comments.

• A key point is that there are indications that observationally-based estimates for equilibrium climate sensitivity are biased low. This is essentially because they assume that the feedback response in the future will be the same as in the past (linear). There are lots of reasons why this is unlikely to be the case. As mentioned in this Isaac Held post, we know that some regions warm faster than others. This will manifest itself as warming faster during the final stages of approaching equilibrium, than during the early stages. There are also indications that the pattern of sea surface warming has lead to a cloud feedback response that is smaller (more negative) than what we might expect to be typical. Therefore we should treat observationally-based climate sensitivity estimates with caution; they may well be biased low.
• In Nic Lewis’s criticism he appears to decide that what should be compared are the best estimates, rather than the ranges. He recomputes the model best estimate and claims it is higher than suggested in the paper, and then compares that to the best estimates from observationally-based estimates (which he claims is between 1.6^oC and 2^oC). This itself seems statistically questionable, but there are also potential issues with how some of the observationally-based best estimates are determined. Nic Lewis, for example, uses a Jeffrey’s prior in his analysis. The Jeffrey’s prior potentially allows for climate sensitivity values that are unphysically low and, consequently, could shift the distribution so that the best estimate is biased low (I think he uses the median, but I can’t quite remember). We had a lengthy discussion of this issue in this post.
• What about some ballpark estimates? We’ve already warmed by about 1^oC. If we continue increasing our emissions, we could double atmospheric CO₂ by the middle of the century. The long-term warming trend suggests that we could easily have warmed by 1.5^oC at that stage. Given the thermal inertia of the oceans and estimates for the planetary heat uptake rate, it seems highly unlikely that the TCR-to-ECS ratio could be larger than 0.8. Hence, if the TCR is around 1.5^oC, that would probably mean the ECS is at least 2^oC, which is right in line with the kind of minimum we’d expect, based on our understanding of the various feedback processes.
• There is also an interesting potential irony to all of this. On the one hand, we sometimes see arguments that we can’t trust climate models because the climate system is non-linear and, hence, chaotic and therefore we can’t make predictions about the future. On the other hand, Lewis’s position is essentially that the system is so simple that we should trust linear models over more complex climate models.

Ultimately, I think that the observationally based estimates, some of which have been done by Nic Lewis, are very useful ways of estimating climate sensitivity. However, they are quite simple and are not really inconsistent with the other estimates (ranges from 1^oC to 3^oC compared to other estimates that have ranges from about 2^oC to 4.5^oC). Searching for errors in any attempt to further reconcile the various estimates doesn’t really make the low climate sensitivity values suggested by these observationally-based estimates more credible. To do that would really require showing that they’re consistent with our understanding of physical climatology. I would argue that there are indications that they are not.

Proposing A Non-Cynical Red Team Exercise

(Guest posting by Michael Tobis. Opinions expressed here are mt’s only.)

Some people who dismiss the climate change issue like to call it “the CAGW hypothesis” for “Catastrophic Anthropogenic Global Warming”.

The name is quadruply irritating, inasmuch as 1) a noun is not a hypothesis, 2) the lack of definition of the hypothesis allows one using the name to rule specific claims in or out for purely rhetorical utility  3) it conflates several ideas and 4) it injects jargon into the debate that the climate-related professions do not use, thereby obfuscating rather than clarifying.

Nevertheless, I think it is fair to say that, um, those people mean SOMETHING by CAGW. They know a CAGW proponent when they see one.

It is true that the consensus is making a claim that on first hearing seems utterly radical and implausible: that very large energetically viable fossil fuel resources must remain untapped.

But that’s not a hypothesis!

The proposition that “catastrophic climate change due to fossil fuel emissions is sufficiently likely that very large energetically viable fossil fuel resources must remain untapped” is in a sense a hypothesis. To be more precise it needs a precise definition of catastrophe. I’ll propose “mortality-driven decline in global population” as a definition of catastrophe.

This leaves us with proposition P: “Mortality-driven decline in human population attributable to large anthropogenic climate change is sufficiently likely to justify urgent and stringent efforts to eliminate fossil fuel energy long before reserves are depleted.” 

That’s a mouthful, and while I’d prefer to call this by some other name, I’m willing to concede the rhetorical point at least for present purposes. I’ll refer to P as the Precise Catastrophic Anthropogenic Global Warming Hypothesis, or PCAGWH.

(It’s pronounced exactly as it’s spelled. I am a genius with acronyms.)

PCAGWH is in a Popperian sense a testable hypothesis. One can fail to restrain fossil fuel consumption and see if catastrophe (as defined above) ensues. The trouble with this test is obvious – the consequences of the test are catastrophic. Avoiding that test is exactly what we are arguing for.

Because the policy we are arguing for is so extreme and unusual, though, the desire for a thorough and responsible review of PCAGWH is a reasonable goal. This brings us to the “red team” proposal.

While many criticisms can be directed at the current administration of the US, which is proposing the exercise, most are not relevant to the idea that PCAGWH should be tested in some other way than simply ignoring it and waiting to see if catastrophe ensues. Regardless of what else you may think about its proponents, this claim is on its face more than reasonable.

Some criticisms of the administration, however, are very relevant.

The administration has expressed vocal hostility and suspicion of advocates of the hypothesis, and its congressional allies have habitually called upon a few credentialed scientists of dubious skill and questionable objectivity to justify such hostility and suspicion. In this context it’s hard for the very community that has been the subject of attacks based on  systematic misattribution and outright fabrication to participate with enthusiasm.

Indeed, more of the same is quite likely to be the intent – fringe characters will hurl accusations as though they were prosecuting attorneys, and legitimate scientists will be forced into a defensive stance rather than allowed to construct a coherent case.

Nevertheless, refusal to participate encourages the view that we are arguing from baseless authority. People inclined to disbelieve the argument for our surprising and, if wrong, very expensive proposition, will have their misapprehension reinforced. This we do not have an ethical right to allow, even if the motivation of those proposing the exercise is entirely disingenuous.

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Again, testing PCAGWH directly amounts to taking no action until global catastrophe emerges, which is exactly what the proposed policy intends to prevent. So since we would rather not test PCAGWH directly let’s look at the reasoning that supports it.

Here’s my initial attempt to simplify it to five key points.

1) Global sensitivity to greenhouse gases is unlikely to be much below 2 degrees C per doubling with a best estimate around 3 C

2) Economically valuable (in an unchanged regulatory environment) fossil fuel reserves provide enough fuel for at least two doublings of CO2 background

3) Consequent changes in excess of 2 C over less than a few centuries are very rapid compared to earth’s past, except possibly in a couple of extremely catastrophic extinction events

4) Economic, social and environmental losses climb rapidly and nonlinearly with temperature change , and may already overwhelm the short-term benefits of fossil fuels, and will very likely do so in the near future. UPDATE for clarification: Costs of a unit of emission aggregated over time may already overwhelm the benefits, which appear immediately. This balance shifts further against the value of emissions as geologically rapid climate change proceeds.

5) Environmental concentration of CO2 emissions is to a good approximation cumulative. CO2 does not naturally vanish from the system on time scales of policy interest.

The conclusion is that, consequently CO2 emissions must cease as quickly as practicable.

Since I’m just a guy on a laptop, I may have missed some points or expressed some poorly. I welcome  suggestions for improvement.

I’d say that each of the points is very robust, each extremely unlikely to be false, and together constitute a strong basis for PCAGWH.

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It’s not a “house of cards” argument, either. Each of these claims is robust, with small but perhaps measurable uncertainty., We are in a risk management scenario. As long as each of these points is as likely as not, we are left in a situation of unacceptable risk.

I’d argue they’re all well established, but I also would like to emphasize point is they don’t have to be to justify a policy response.

Now, when the administration proposes a “red team” exercise, they are not doing so because they care about the state of science itself. They are not comparably interested in herpetology or particle physics. Clearly, their interest is in the policy implications of the science.

So, arguments ad hominem, arguments about specific statistical nits or personalities, arguments about specific excessive claims by overzealous individuals, arguments that this or that person has been ill-treated by this or that community or institution, all the nitpicking about this or that graph are beside the point. The first thing we must expect of a fair red team exercise is that it will eschew all the marginal noise that exists mostly to reflect on the morality of the community of relevant scientists (justifiably or not!).

A legitimate red team exercise would look at the component arguments and establish whether any of them is so grossly unlikely to be true as to overturn the claim that fossil fuels must remain untapped.

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Insofar as the red team is examining the role of climate science in the PCAGW hypothesis, this limits questions of interest specifically to some narrow topics. In my own formulation, these would be #1 and #3:

1) Global sensitivity to greenhouse gases is unlikely to be much below 2 degrees C per doubling with a best estimate around 3 C

3) Consequent changes in excess of 2 C over less than a few centuries are very rapid compared to earth’s past, except possibly in a couple of extremely catastrophic extinction events.

===

These are consensus claims in climate science. Each of these is quite amenable to a fair-minded red-team exercise.

My interest would be in a fair assessment of point 1 which addresses physical climatology, but point 3 (paleoclimatology) is also important and I’ll address it briefly.

I think point relatively 3 is easy to address, insofar as it is a question to which expertise in geological science can be applied. One could easily assemble a red team from branches of the earth science that are not closely involved in climate who would be competent to address the evidence. The proposition that the realistically anticipated changes would be very large compared to events in the natural history of the planet can be fairly evaluated by people without a dog in the hunt, beyond the desire to get the answer right.

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Let me get back to the physical climatology question, point 1.

What all this is leading up to is a challenge I’ve meant to address to those claiming that climate science is weak and that climate modeling doesn’t provide any evidence worthy of note.

I strongly believe, to the contrary, that general circulation modeling, which is the common core of climate models and weather models, is an extraordinary triumph of science.

This is because GCMs produce model weather which is sufficiently and so sustainably analogous to the actual weather of the world that a realistic climate emerges. Climate is not an input to theses systems. (They are unlike economists’ Integrated Assessment Models in this way!) What the models are told about the world is the constitutive small-scale phenomenology, and realistic approximations to boundary conditions and forcing. Storms and dry zones form in the models in the right places. The models explicitly represent the radiative transfer of the planet among the small-scale phenomenology. So the greenhouse effect is itself not explicit – it’s an emergent property of the radiative transfer.

There’s a lot to argue about in this effort, and I have been close enough to the field that I can attest that healthy and skeptical arguments do occur constantly and vigorously.

It’s important to understand that climatology exists as an independent discipline, studying many phenomena outside the domain of policy interest, and these models are crucial tools in that effort. But there’s no denying that projection of future climate change is a key objective, and that this application presents a number of interesting challenges.

But for the purposes of testing PCAGWH, the issue at hand boils down simply to this: if the sensitivity is low enough not to worry about, why is there not a single working CGCM that produces a respectable climate simulation with such a low sensitivity?

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It’s not as if the petroleum industry lacks the skill or resources to produce such a model if it were possible. Nor, obviously, do they lack the motivation. Indeed, I am acquainted with a PhD climate modeler who worked for many years for a major petroleum corporation in their oil exploration department, modeling the carboniferous climate to identify places where oil deposits might have formed! That is, at least one oil company had climate modeling experience in house!

Those determined to claim that we don’t need to stop emitting CO2 are being utterly illogical if they don’t assert a sensitivity to CO2 doubling well lower than the IPCC low end with confidence.

They also claim the evidence of models is negligible, in that models in their view can be tuned to produce a “desired” result. (That we don’t actually desire the result we are getting escapes their imagination altogether!)

Well, the Hungarians have a lovely word, tessek (pronounced tesh-shake), which means, by all means, please, help yourself. Sometimes it is meant politely, and sometimes sardonically. But by all means, go ahead. I’m sure somebody would provide you with CGCM code. Go fix it so it has a low sensitivity without breaking the model climate.

===

There are several reasons to think of this as a fair exercise, in a way that the usual bluster from the usual suspects would not be.

For one thing, any member of the ordinary climate modeling community could easily participate. It’s a legitimate form of research – find the lower bound for plausible CGCM Charney sensitivity. Call me up, I’d probably pitch in.

Also, the otherwise inevitable vexing question of whether Dr X or Dr Y who is now clamouring to be on the “Red Team” is or is not a legitimate source of climate expertise becomes moot. Either they can help to build a working climate model or they can’t.

This also moots the question of whether the models are in any sense “good” or “bad”. The objective of the Red Team would be only to produce a version of a CGCM that is *as good* on various metrics as extant models. If that isn’t very good, so be it, it just leaves them a lower bar to hurdle.

Finally, until and unless they meet this challenge, I think we have an objective basis to claim that the critics do not have a grip on the state of the science as embodied in the models.

===

Please note that a single model with low sensitivity would be a very long way from establishing the proposition that low sensitivity is certain enough to moot the problem. But I think the absence of such a model to date constitutes very strong evidence that a low sensitivity is not possible.

Again, the motivation, skill and resources are all available. Yet nobody, and specifically none of the oil majors, has done so.

Why not?

If they want to red team the models, I say we try very hard to help them. Anyone willing to take this challenge seriously would learn something, and they might teach us something as well.

As long as they don’t have a red team GCM, all they have is bluster and hostility. If they want to be taken seriously as a team, let them play the game.

 

Hawking is wrong

I guess the big alarmist news at the moment is that Stephen Hawking has been quoted as saying:

Trump’s action could push the Earth over the brink, to become like Venus, with a temperature of two hundred and fifty degrees, and raining sulphuric acid.

Well, this is simply not true. As this Climate Feedback says:

It is not possible for Earth’s climate to become as extreme as Venus’ climate in the foreseeable future. And even extreme global warming would not be linked to sulfuric acid precipitation, which occurs on Venus because of volcanic emissions of sulfur gas.

As Chris Colose mentions in the Climate Feedback article, it is theoretically possible to make modern Earth hot enough such that the upper atmosphere becomes quite wet and conducive to substantial water loss to space. However, even this would not be a Venus-like runaway and it is also extremely unlikely (probably, virtually impossible).

On Twitter, Robert Grumbine made the point that a Venus-like runaway is far less likely than something like an extinction-level asteroid strike, and we don’t exactly go around worrying about something like that (we do, however, commit some resources to keeping track of asteroids).

As Ken Caldeira also pointed out, unrestrained fossil fuel burning likely leads to nasty climates, but not as nasty as Venus. I think this is a key point; we don’t need to invoke extremely unlikely (virtually impossible) catastrophic scenarios in order to argue that continuing to pump CO₂ into the atmosphere might be a really bad idea.

So, one of the obvious problems with what Hawking has said is that it is simply wrong. The other is that this is an important issue and we really should be discussing the real consequences of continuing to emit CO₂ into the atmosphere, not having to deal with high-profile people making alarmist claims. Of course, in the grand scheme of things, this is probably just another blip along the ever complicated climate communication highway, but it would be nice if people who should know better didn’t keep scoring these kind of own goals.

Links:
Stoat on Hawking radiation.

Temperature targets

I realise Michael Tobis is planning a follow-up to his post, but I thought would quickly pen this post about temperature targets, for example the Paris target of

keeping the increase in global average temperature to well below 2°C above pre-industrial levels [and] to aim to limit the increase to 1.5°C.

Many people argue that such target are purely political. Of course, a decision to try and achieve some goal will always be political, but that doesn’t mean that one can’t find some kind of justification for that choice of target.

Credit: Schellnhuber et al. (2016)

On that note, I recently came across a paper by Hans Joachim Schellnhuber, Stefan Rahmstorf and Ricarda Winkelmann called Why the right climate target was agreed in Paris. It includes the figure on the right which shows the surface temperature through the Holocene, the instrumental record, and future projections. The grey band is the Paris range, and the colored bars show various tipping points (defined as major subsystems of the climate being destabilised).

What this shows is that if we exceed the Paris target, then coral reefs will almost certainly pass a tipping point, and Arctic summer sea ice, Alpine glaciers, the West Antarctic Ice Sheet, and Greenland may also be destabilised. Other tipping points will probably only be triggered if we fail to keep warming below 4^oC, but that is roughly where we’re heading with current commitments.

So, even though deciding on a target is clearly a political decision, there can still be justifications for choosing certain targets. The Paris target will at least give us a chance of not destabilising a major climate subsystem. Something to bear in mind, though, is that the carbon budgets associated with these temperature targets only give us a 66% (or, sometimes, 50%) chance of achieving this target. Even if we do reduce emissions in line with the Paris target, we may still not achieve the target. Similarly, our current commitments are in line with keeping warming below about 3.5^oC, but even if we do follow this pathway we may still not keep warming below 3.5^oC. One might argue that we should really be doing more, rather than less. Given this, maybe one way to frame proposals for a Red Team exercise is to insist that those who support this, acknowledge that delaying action could significantly increase the chance of passing a number of these tipping points.

Anyway, to finish this post I’ll simply highlight that there is another paper suggesting that observationally based climate sensitivity estimates are biased low. I’ve also added a video below, by Stefan Rahmstorf, that discusses the figure I’ve put in this post.

The Only Way Not To Lose Is to Play

(Guest article by Michael Tobis; opinions are mt’s only)

There’s a lot of talk about a “red team” critique of climate science from the quarters that have aligned themselves as critics of the mainstream. This has recently been taken up by the secretary of the US Department of Energy, Rick Perry, so suddenly the idea has legs.

All too often, extraordinarily harsh criticisms are aimed at physical climatology, a field which is much maligned and, partly as a consequence, woefully underestimated.

Look, the earth is many things, but one of the things it is is a physical object in space with physical properties. As such it is well-observed and extremely interesting. Admittedly, it’s also very complex, but there’s no fundamental reason that physical science would fail to grapple with the earth as an object. And it hasn’t.

The knowledge of the earth, as an object that responds dynamically to the physical laws governing its properties, is deep and rich and admirable. It’s not the fault of the science that it has a result of consequence to deliver.

In fact, were it not for climate disruption (a.k.a. “global warming”) there’s a good case to be made that climatology would be taking over from physics as queen of the sciences in the computational era.

While there’s a sound foundation for climatology that (barely) predates the computational science era (essentially the basics of physical climatology were codified in a 1967 monograph by Ed Lorenz) it’s the progress that has been made since the first successful general circulation models that makes the field so exemplary of modern, computationally driven science.

All of this is buried under all the ridiculous noise. Climate disruption is a problem, and there are those who seek to obscure that fact for selfish reasons. So they malign the science, even though the core of it is a triumph that should be celebrated.

I’m not under any misapprehension that the impetus for the “red team” isn’t very much under the influence of this malice. The revulsion of the climate community (“we’ve been red-teaming each other for decades!”) is therefore understandable.

I’d like to advocate that we resist this visceral response and embrace this as an opportunity.

First, there’s an obvious disadvantage to eschewing the effort. And second, there’s an advantage to participating in it. In a subsequent essay I will propose a specific strategy. For now, I’ll just explain why I think we should play.

(via Peter Jacobs on Twitter)

Let’s make no mistake about whom to expect on the “Red Team” as implemented by the current US administration: the usual hacks whom the Republicans call to testify before congress, i.e., people of modest competence whose claims happen to align with what Republicans want to hear. (It’s a career strategy after all – whether this is a matter of conscious hypocrisy or incompetence or some complex combination of the two is a matter of relative indifference. The point is that these people don’t constitute a credible red team).

Rejecting this plan out of hand, however, has the very severe disadvantage that it can be used as evidence for the most extreme claims about climate science – explicitly that we argue from authority and have no significant evidence behind our claims; implicitly that we have no substantive science at all and exist only to advance an agenda.

Standoffishness on our part results in an immediate win for our most  irresponsible opponents. It looks as if we can’t bear criticism, even if what we are having trouble bearing is stubbornly obstinate irresponsible attacks.

Embracing the red team idea requires that we insist on fairness.

We must make a case that if the “red team” is constituted by people we consider hacks, we should have as much opportunity to critique them as they do us. What we need is some impartial, scientifically competent referees, or else an intellectually uncommitted, scientifically competent red team. If the “red team” is the likes of Curry, Christy, Happer etc., they’ll be doing the usual thing – presenting an incompetent muddle as a reasonable alternative to a mature science. They may honestly not know better, but the scientific community does, and we need some way to objectively make that case.

Or, we could be happy with a conventional red team, where people of extraordinary competence and no axe to grind were brought in to revisit the evidence.

As long as we could ensure participation by somebody other than the usual NIPCC gang, whether as the red team or as adjudicators of the exercise, we could make lemonade out of these lemons.

Of course, we aren’t really talking about science, but about politics hiding behind science’s skirt.

As Gavin Schmidt points out:

(via Gavin Schmidt on Twitter)

I don’t suppose there is a final victory over the forces of denial in prospect.

But I think we can hardly do worse than boycott this exercise. What’s more, I suspect we can do even better than to merely defang this effort and make yet another mainstream report.

I suggest we can frame this in a way that the truth can’t really lose at all.

The short version is this: why can’t they build a decent climate model with low sensitivity? If they could, that would be a real red team effort, not just a bunch of posturing hacks. If they can’t, well then, there is no meaningful red team critique possible.

I’ll expand on this in another essay soon.