BBC interview: global warming pause, climate sceptics, long timescales

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I was interviewed by Matt McGrath from the BBC last week, as were several other Dutch climate spokespeople (including PBL’s senior scientist Arthur Petersen and skeptical science writer/journalist Marcel Crok). Short parts of these interviews have appeared on the web  and on Radio 4 (“The World Tonight”, 26-09). Below I try to provide a bit of context to my quotes.

Both pieces are centred, as is fashionable these days, on the apparent smaller rate of surface warming in the past 15 years. The web piece is entitled “Climate sceptics claim warming pause backs their view”. Of course they claim it does. What sceptics did achieve –credit where credit is due- is to put this so-called “pause” on the agenda of mainstream media, until it got so fashionable that they all feel forced to use it as an anchor for any reporting on climate. But, as Gavin Schmidt is quoted as saying:

focus on a global warming pause over the past 15 years is a “misplaced” distraction that misses the big picture. He said, “The IPCC and the issue of climate change is not about the weather next year or the next five years; it’s about the long-term climate change that we are engendering.”

See also this useful figure from Stefan Rahmstorf, underscoring the silliness of drawing all too strong conclusions from 15-year trends.

giss2012c - Rahmstorf - Global temp with two silly trendlines

Figure showing NASA GISS global average temperatures with trendlines from 1992-2006 (light blue) and 1998-2012 (green) as well as the most recent 30-year trend in red. Naturally, starting in a very cold volcano-influenced or very warm El Nino influenced year will inflate or deflate the trend. (source: Stefan Rahmstorf)

I am quoted in the BBC piece as follows:

Bart Verheggen is an atmospheric scientist and blogger who supports the mainstream view of global warming. He said that sceptics have discouraged an open scientific debate.

“When scientists start to notice that their science is being distorted in public by these people who say they are the champions of the scientific method, that could make mainstream researchers more defensive.

“Scientists probably think twice now about writing things down. They probably think twice about how this could be twisted by contrarians.”

The discussion was about to what extent climate science isn’t open/transparent enough, as contrarians routinely claim. Matt also asked to what extent skeptics actually play a positive role in making science more open/transparent and more self-critical. I said ideally they would. People who are critical usually have a good influence that way. But many climate contrarians don’t just stop at raising partly valid criticism, but go on to distort the science. That has the opposite influence, as scientists noticing this behavior become more careful and more defensive, and(have to) think ahead how their words might get twisted by contrarians. So they may become less open and less frank, and more careful in how they chose their words.

That is the opposite of what contrarians claim they want to achieve, so it’s quite ironic (though entirely logical) that this is the more likely effect of their behavior. It shows quite a lack of self-awareness on their part that they don’t see how their actions and their behavior affect the dynamics of the public debate. For the worse, in most –though not all- cases.

There may also be some lack of self-awareness among the mainstream that they respond in a way that’s not conducive to a long-term open and frank dialogue with society. From an older comment of mine:

If the valid criticisms wouldn’t be packaged in such conspiratorial/accusative/exaggerated (c/a/e) ways, they would be welcomed much more than they currently are. The art that mainstream scientists and their defenders must learn is to take the valid parts of the criticisms and deal with/respond to them, and leave the c/a/e packaging for what it is. That is increasingly difficult because the critics and their supporters will try to keep the c/a/e in (presumably because this packaging is what is most effective at decreasing the scientists’ credibility and sowing doubt). That dynamic needs to be broken. It needs effort from both sides, as difficult and unfair as it sounds.

As I wrote in my earliest (and still rather positive) reflection on the Curry-turn:

There is a tendency of ‘circling the wagons’ within the scientific community, in response to the continuous attacks on the science. Attacks that are mostly based on smear and insinuation rather than solid arguments. (…) I think the ’us-versus-them’ feeling amongst many scientists and their supporters is understandable (as a reaction to the contrarian c/a/e attacks on the science), but counterproductive in the long run.

In the Radio 4 show (at ~33:50 min in; earlier in the downloadable mp3 version), I am saying a few things about the timescale of the problem and of the solution. I brought this up when the discussion was about whether we now have more time to respond to climate change. This is a vastly underappreciated point in the climate discussion:  The climate system will take much longer to cool down than it did to warm up. This is a consequence of how the carbon cycle works. In this context, I said the following:

We’re going somewhere, and if we don’t like where we’re going, we have to turn that wheel in time.  As when you’re on a giant supertanker on the ocean, you can’t say “oh, I’ll wait until I can feel the iceberg with my pinkie and then I’ll turn the wheel”. Then you’re a bit late, so you have to start doing that in time. That’s the other side of the coin. But if you keep banging the drum saying “it’s five to twelve! It’s five to twelve!” doesn’t work either. And that could be counter-effective to engage those who are a bit more skeptical.

Global warming is a problem in slow-motion, hence the “five to twelve” line is not the most useful one to get people on their feet, because if it remains five to twelve for too long, they will tune you out. That’s what happened in the aftermath of COP15 in Copenhagen for example (where the 5-to-12 line was used a lot, and not much has changed in the years since). The supertanker analogy is more appropriate I find, since that makes clear that even though the problematic situation that’s on your path isn’t in close proximity yet, it is necessary to change course, if you wish to avoid it.

Supertanker

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13 Responses to “BBC interview: global warming pause, climate sceptics, long timescales”

  1. David Young Says:

    I think Bart you are missing the point about the pause that is being made by skeptics. It is the same point made by Von Storch and others in the “consensus”, viz., that the GCM’s seem unable to predict it, calling into question their prominent role in climate science and policy discussions. GCM’s also seem incomsistent with recent observationally constrained estimates of climate sensitivity.

    I think you have a larger problem. You choose to focus on the more extreme skeptics and fall into the very trap you discuss above. You should address the valid part of any skeptical argument. Climate scientists are supposed to be the grown ups here and claim an authoritative role. That role requires special responsibilities as well.

    I also don’t understand this fear that something you say will be distorted by someone who doesn’t like you. Welcome to the adult real world!

  2. cynicus Says:

    David Young,

    Climate modellers (nor the IPCC for that matter) have never claimed that models would be able to predict the timing of internal variability. And they don’t really need to for the purpose of solving long term climate.

    Predicting the timing and extent of internal variability is an initial value problem (requiring the model to be initiated with very detailed and up to date observations) while climate models are focussing on long term average weather which is more like solving a boundary value problem to constrain climate over long periods.

    When you’re primary goal is to look at the long term you don’t need to solve the difficult initial value problem in an attempt to acurately predict timing and duration of short-lived internal variability (ask any weather modeller how difficult it is to get the current state of ocean and atmosfphere and input it into the model asap). This chaotic random internal variability will average out for longer timescales.

    Pointing at the lack of accuracy in climate models solving the initial value problem as a shortcoming of these models while they’re only supposed to solve the boundary value problem, one might think, is rather missing the point.

  3. David Young Says:

    cynicus, I know that is the standard Schmidt doctrine. I’ve yet to figure out exactly what this “boundary value problem” is. The climate is an initial value problem with varying forcings, in mathematics these are known as forcings, i.e, right hand sides. They are not boundary values in the technical sense.

    The only way this boundary value problem idea makes any sense is to claim that the attractor is so strong it eventually sucks in all trajectories, no matter how large the intervening errors. For climate models, of course these trajectories are totally wrong, but the argument is at least plausible. But we know, for example, that the Lorentz attractor is complex. To say that the attractor is the “climate” is to gloss over the issue. The attractor itself can have very high dimension. Which “dimension” you end up at is highly sensitive to initial conditions.

    Summarizing, the doctrine of the attractor is little more than a communication gloss on a much more complex truth.

    In any case, computational evidence shows that GCM’s are too dissipative, i.e., dynamics is damped over time. This is caused by the numerical viscosity which is large and in fact artificially enhanced by something known as eddy viscosity, which is used to “average” turbulence. Eddy viscosity is always too dissipative. And then there is the viscosity caused by the grid spacing. This is something every 1st year graduate student in numerical PDE’s learns. Yet, it is never discussed in the context of GCM’s. Why do you think that is the case?

  4. cynicus Says:

    David, perhaps not understanding the difference between predicting the exact future state of chaos based on accurate observations now and predicting climate boundaries over long time scales is the problem. Climate is average weather therefore the initial value is not relevant, climate models don’t have to accurately predict chaos in timing and extent, it just has to predict the boundaries of the possible chaos.
    This thought is not, as you seem to think, ‘a standard Schmidt doctrine’ (your framing suggests that this in itself would be a problem?), it is a fundamental part of climate modelling. Even early papers on climate models by e.g. Syukuro Manabe or Stephen Schneider from the 60s and 70s show that they understood the difference.

    Anyway, Von Storch and others are unfortunately setting up a straw man, claiming that climate models -used to predict climate over long timescales- should be able to predict the actual state of short timescale chaos at any given time when no-one ever claimed that those models would be able to do that.

    I agree that it would be strange when climate models did not address a significant problem that every ‘1st year grad student in PDE’s would learn’. For a long time there are plenty of models around, created by many different people with different backgrounds. It would be a strange coincidence that none of these studied There’s also a large body of paper on implementing eddy turbulence in models. So instead of crying wolf I would first assume such basics are long solved which is why this particular problem is not discussed much.

    But I could be wrong and you seem very sure of your case, so it would be great if you could provide links to the literature pointing out the eddy viscosity problem in climate models, what it’s implications would be on the GCM results and whether it drastically changes the conclusions we draw from them?

  5. cynicus Says:

    Whoops, one sentence got mangled.

    I meant to say: It would be a strange coincidence that none of these studied eddy turbulence in 1st year.

  6. cynicus Says:

    Whoops II, this is not what I should have said:
    “it just has to predict the boundaries of the possible chaos.”

    Excuse my confusion, I was talking about configuration, so I should have said:
    it just has to be configured with the correct boundaries, like (changing) incoming solar radiation or (changing) greenhouse gas concentrations).

  7. David Young Says:

    Cynicus, I haven’t forgotten about your request but need more time to assemble references.

  8. cynicus Says:

    Great, thanks :)

  9. David Young Says:

    OK, I still am time constrained. Can I ask you to look at James’ I think in the “more on that sensitivy paper” thread. I do give some references there that at least will be a starting point. Wish I had more time. :-(

  10. Viktor Says:

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  11. deminthon Says:

    “you are missing the point about the pause that is being made by skeptics”

    This is quite ironic as DY misses the point of this article and of all of climate science: AGW is real, as demonstrated overwhelmingly by numerous lines of evidence, not least of which is the long term trend line. “scepticism” based on attacking just one of these lines of evidence is not valid, it isn’t genuine “scepticism”, it isn’t science, it doesn’t reach toward the truth or lead to the truth.

  12. BrianD Says:

    When you said conspiratorial/accusative/exaggerated I assumed you were talking about the Al Gore Environmentalists.

  13. Bart Verheggen Says:

    BrianD,

    Interesting. I had climate contrarians in mind, but of course the general dynamic works in both directions, and communication between people with very different opinions is improved if a) conspiratorial/accusative/exaggerating packaging is minimized in speaking and b) ignored as much as possible in listening. The animosity between different “camps” make both very difficult.

    If the valid criticisms wouldn’t be packaged in such conspiratorial/accusative/exaggerated (c/a/e) ways, they would be welcomed much more than they currently are. The art that mainstream scientists and their defenders must learn is to take the valid parts of the criticisms and deal with/respond to them, and leave the c/a/e packaging for what it is. That is increasingly difficult because the critics and their supporters will try to keep the c/a/e in (presumably because this packaging is what is most effective at decreasing the scientists’ credibility and sowing doubt). That dynamic needs to be broken. It needs effort from both sides, as difficult and unfair as it sounds.

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