Arnold Kling  

Some Denialist Arguments

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From David Evans.


The signature of an increased greenhouse effect is a hot spot about 10km up in the atmosphere over the tropics. We have been measuring the atmosphere for decades using radiosondes: weather balloons with thermometers that radio back the temperature as the balloon ascends through the atmosphere. They show no hot spot. Whatsoever.

The way I look at it, the whole issue in global warming is to find the smoking gun, so to speak, that links carbon dioxide to global warming. This "greenhouse signature" sounds like it would have been a real smoking gun.

Of course, one can argue that by the time we find the smoking gun it may be too late. Perhaps in the meantime we'd better play it safe and act as if the global warming thesis is true. That would not be my position, though.

UPDATE: In the comments, Tim Lambert writes,


The signature of an increased greenhouse effect is not a hot spot 10km up. That effect is a predicted consequence of surface warming, whether from greenhouse or the sun.

The signature of greenhouse warming is stratospheric cooling. Which is what we're seeing. Which is why Evans doesn't mention it.


More Denialism, from dissident and peer-disdained physicists, here and here


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COMMENTS (22 to date)
Gary Rogers writes:

I am not sure even a smoking gun is enough. A proven solution also needs to be included.

Max M writes:

That seems a bit too strong of a requirement. Like all good sciences, shouldn't we expect either a smoking gun or a host of mutually supporting evidence that triangulates upon the "best explanation" being global warming? That seems to be the way we do it in every other discipline, and I believe if scientists are heading in a certain direction on this one, its towards the triangulating mutually supporting evidence.

~Max M

Ned writes:

The evidence outlined in the original article seems like a pretty big deal. Arnold, why don't you e-mail this to Greg Mankiw (his blog doesn't accept comments any more) - he should probably disband his 'Pigou Club' :-)

It's too bad about the article's title. Something like "The Global Warming Scare Over" would seem more appropriate.

Mr. Econotarian writes:

Perhaps in the meantime we'd better play it safe and act as if the global warming thesis is true.

The question is whether we should play it safe by carbon taxing the planet into maintaining large amounts of poverty, or just letting all the poor people get rich by extending them economic freedom so they might be able to buy air conditioners, DDT, and other things to fight the symptoms of global warming. (My take on public choice is that the latter is more likely, though both take a lot of effort).

BTW, Al Gore again said he was still in the Pigou Club, even to the extent of reducing payroll taxes!

"He again called for a carbon tax to compensate for a reduced payroll tax."

http://www.bloomberg.com/apps/news?pid=20601087&sid=aORYKLlpOoKA&refer=home

dearieme writes:

This article backs up my suspicion that Global Warming started off as inept science, and descended into mere crookedness.

jb writes:

AGW didn't start with inept science. It started with sensible science - the more CO2 in the air, the more sunlight would be reflected back on the Earth's surface. This is a fact, that no sensible person denies.

What sensible people deny is the magnitude of the change, as well as the concept that a relatively small change in CO2 levels will set off a series of other, larger changes.

When you don't know the answer, as the original climate researchers did not, it's not unreasonable to extrapolate the worst-case scenario - CO2 increases will possibly increase the amount of water vapor in the air, and water vapor is a very powerful greenhouse gas.

So James Hansen ran his models, and tweaked and tweaked and tweaked them, until they seemed to be able to properly model the past, and then he set them loose on the future.

And his models showed a lot of warming. And Dr. Hansen, seeking more grandeur for himself, more funding, perhaps also holding a significant antipathy towards the free market and the business world, ran with his models to the UN, to whoever would listen, and he told his story, and pointed to the upswings in his graphs.

And people listened. Dr. Hansen is a well-regarded scientist. He had models and charts and 30 year predictions of dangerous warming.

A lot of people were attracted to the predictions because they helped them legitimize political arguments around constraining businesses and the free market. A number of other people were attracted to the predictions because they were fashionable. But many people were attracted because they needed an enemy to rally against. With the death of communism, the failures of planned economies, the US lacked a meaningful challenge.

But here was something, that was huge, deadly and, best of all, altruistic. Fighting for a "better managed" world was the height of selflessness. I will have to give up my baubles and primitive conveyances... yes, I will suffer, but it will be for a good cause.

Self-sacrifice in the name of a grand vision is highly romantic, highly motivating.

And so it escalated. And more research was done, and more discoveries were made.

Peat bogs give off methane! Melting ice reduces albedo! Cow farts are greenhouse gasses! Each new discovery seemed to make the situation worse.

But what I believe all the AGW adherents failed to understand was that every new discovery undermined the accuracy and worthyness of Hansen's models. If Hansen's models did not take methane and albedo into account, they were not good models.

And it also begged the question - what else do we not know?

Since 1988, we've learned a lot - cloud behavior in a warmer world is still puzzling, but the Pacific Decadal Oscillation is now understood, the role of the variability of the Sun is better understood, and measurement after measurement has shown that the warming that has been predicted for the last 20 years seems to have spiked in 1998, and dropped significantly since then.

So, we have known for some time that the models were wrong. Now, we also know that the predictions are wrong.

But like communism, the AGW adherents are not going to give up their concerns lightly. They invested tremendous amounts of themselves into caring about CO2 levels, caring about the Earth, caring about the pollution and negative externalities of markets.

They will not let these things go anytime soon. Someday, someone will write a book 'The Warming that Failed' or somesuch, interviews with AGW adherents who eventually realized that they were wrong, and that they had wasted much of their lives caring about the wrong things.

But it will not be anytime soon. 10 years or more, is my guess. And for some, it will never happen.

William Newman writes:

Harsh.

I'm not enough of an expert in the field to say "yep" with any great confidence. But I am very happy to see a high-profile specific challenge close to one of my main points of curiosity, so I'll at least say "hear, hear."

I did modelling in intractable messy systems for a while (biomolecules in solution). I have been very unhappy about the fancy climate models that are supposed to be mature and reliable enough to base policy on. Complex models in hairy systems are OK with me: even models that left me theoretically queasy (density functional theory, e.g.) have been very successful. And advocates are OK with me. But I want to see fancy model advocates trumpeting their record of successful detailed predictions not matched by competing models, especially simpler competing models.

I find plenty of crisis-AGW advocates energetically stomping on the particular model of the no-warming, no-CO2-rise, no-nothing superduperdenialists. That energy is understandable, but not particularly relevant to my concerns. I find hindcasts, and I find forecasts of the overall climate with such wide unclear specifications and wide spreads that they're not clearly distinguished from dumb models.

For a denialist earth-hater ex-modeller like me, what would be more convincing would be sharp comparison of a few chosen (by the modeller) particularly-sensitive "fingerprint" values (e.g., the temperature anomaly at 10km discussed by Evans) to all popular alternative simple-minded models. (An example of a simple-minded model: "linearly extrapolate from fits to the climate over the past N years," corresponding to the vague theory that clearly the climate has long-term fluctuations, and this seems to be one, but we're agnostic about the cause.) And, of course, I'd like to see impressively good fit between the old predictions and recently measured data.

Of course, a good fit of predicted policy-relevant values (climate properties in various regions, mostly) would be even better. But in many fields that can be much harder and slower than the modelling fingerprint-ish values, so good fit of the modeller's choice of fingerprints can be an important first step toward a technical consensus.

Now that Evans' criticism has been published, I look forward to surfing to advocacy websites connected to IPCC report authors, and expecting one or more articles endeavoring to refute him. And if the models really have been usefully mature for as long as the debate has been going on, I expect many of those refutations should be prominently pointing to the designed-to-be-clear designed-to-be-verifiable fingerprint-ish recorded predictions of old consensus computer models, and the recent data which sharply distinguish the success of those old predictions from the lesser success of the plausible simple-minded models.

frankcross writes:

I would like to say this is a strawman, but it's not, alarmists have exaggerated warming. But the real issue isn't contemporary warming. The evidence suggests that a total doubling of CO2 produces a 1C increase in temperature. The problem should be viewed as one that is decades out. There's no need for immediate dramatic action but there is a legitimate concern for potential quintupling or more in the future, which won't show up until then, by which time it would be too late

bartman writes:

the more CO2 in the air, the more sunlight would be reflected back on the Earth's surface. This is a fact, that no sensible person denies.

I am a sensible person denying your "fact." That is not how he greenhouse effect works.

CO2 does not "reflect" anything. It is transparent and at a very low concentration. What it does do is absorb short-wavelength radiation that has been reflected back towards space from the earth's surface, causing the lower troposphere to warm, with that warmth conducting to lower layers of the atmosphere.

BTW, I stopped reading your opus at the above-quoted sentence. Demonstrating basic scientific illiteracy in your first paragraph is a surefire way to lose the discerning reader.

Les writes:

I'm not a climate expert, but I do understand multivariate statistics. From what I have read, there is no credible evidence of global warming in the past 100 years. Average global temperature has changed only about one degree Centigrade in 100 years.

It seems that all projections of disastrous global warming are simply based upon predictions and/or computer models. Given the breathtaking lack of validity for predictions and/or computer models, it appears that so-called "global warming" should be viewed with a large grain of salt.

Tim Lambert writes:

The signature of an increased greenhouse effect is not a hot spot 10km up. That effect is a predicted consequence of surface warming, whether from greenhouse or the sun.

The signature of greenhouse warming is stratospheric cooling. Which is what we're seeing. Which is why Evans doesn't mention it.

Josh writes:

I disagree with Tim Lambert. The IPCC report has a nice picture that shows what they expect to be the temperature response by latitude and altitude for all the different forcings (solar and GHG being two of them). See:

http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter9.pdf

Figure 9.1 on page 675 (or pg 13 in the pdf).

It is also faithfully reproduced here:

http://www.aps.org/units/fps/newsletters/200807/images/figure4.gif

They clearly show a hot-spot from 8-12km for GHG (c), while no such hot-spot exists for solar forcing (a).

Adam writes:
The signature of an increased greenhouse effect is not a hot spot 10km up. That effect is a predicted consequence of surface warming, whether from greenhouse or the sun.

I'm confused. If this is a predicted consequence of surface warming from greenhouse, shouldn't we be seeing it as well? Is the surface not warming from greenhouse gasses?

Tim Lambert writes:

Josh: There isn't a hot spot from natural solar forcing but there isn't much surface warming either. If you plug enough solar forcing into the models to produce observed surface warming then you get a hot spot.

I've put some pictures here.

Kit writes:

Tim Lambert: The models tell us we should be seeing a hot spot from the greenhouse effect. So are you saying the models are wrong?

Paul writes:

Tim Lambert, as usual, doesn't know what he's talking about. The earth is at radiative equilibrium at 10 to 12 kilometers above the earth. That is the point at which greenhouse gases exert the most influence because that is the point where convection becomes unimportant and radiative heat transfer become dominant. That's why David Evans makes the argument he does.

Not only is there no smoking gun for global warming. There's isn't even any evidence that the warming we have seen (if you can trust the temperature data, a very big if) isn't entirely natural in origin.

pj writes:

Tim Lambert is quite wrong, and not only for the reasons the other commenters point out.

One observation to note is that the stratosphere has been warming, not cooling, since 1995. This fits with the observation of decreasing global temperatures since 1998. On the other hand, CO2 has been rising continuously. This timing is consistent with other causes for stratospheric cooling besides greenhouse gases. For instance, the sun's radiation, whether measured by its magnetic field strength, the solar wind, radio or ultraviolet-X-ray radiation, was increasing 1875-1995 and has been decreasing since. This is also one of the hypothetical influences on global temperatures. It should be noted that no one believes we have a satisfactory model of stratospheric temperatures, so these empirical data may constitute the bulk of the trustworthy evidence.

But even if we suppose that stratospheric cooling is a marker of an enhanced greenhouse effect, that doesn't mean it's brought about by CO2. Indeed, rising temperatures increase the amount of water vapor in the atmosphere, and the greenhouse effect from this added H2O is stronger than the greenhouse effect from rising CO2. So the observed greenhouse effect may just be an effect of rising temperatures, not the cause. Again, the models are not solid enough to distinguish based on magnitudes.

Now, Lambert argues that the models focusing on 10K temperatures as the best marker are mistaken, and it's possible to make this case, but models focusing on stratospheric cooling as the best marker are on even shakier ground. The fact is the stratosphere has such a low heat capacity that small changes in model parameters can make huge differences in stratospheric temperatures. Stratospheric temperatures are just not understood.

So Lambert is just blowing smoke.

William Newman writes:

I Googled [stratospheric cooling "IPCC WGI Third Assessment Report"] to try to target the consensus 10 years ago. I Googled ["stratospheric cooling" ipcc] to target more current stuff. It appears that Tim Lambert is correct that advocates are choosing politically convenient oversimplifications here. The phrase "stratospheric cooling" seems to typically show up with something like "tropospheric warming." And in the models of 10 years ago, it seems to be tropical tropospheric warming. From the written history of the period Evans and Lambert are describing, it looks as though the two claims typically travelled together, even though each advocate prefers to focus on one.

The first hit on the first search is a draft of Chapter 9 IPCC TAR,
http://clima.casaccia.enea.it/ipcc/focalpoint/wg1/Documenti_preparatori/Ch09_draft3.pdf . (W00t, I hadn't known there TAR text online, I thought I had to buy it or borrow it from a major library, and that I couldn't use a computer to search its text.) I searched that chapter for "stratosphere." From this time capsure, doesn't look to me as though in 2000 AD people thought "the signature of greenhouse warming is stratospheric cooling." "Signature" and "fingerprint" don't appear in the main text. "Stratosph" appears various places, notably the summary figure on page 102. There, both troposphere warming and stratosphere cooling are given the same three-asterisk code indicating "virtually certain."

The chapter draft has many predictions starting on p. 4, but avoids quantitative predictions with confidence intervals. Good luck convincing technically-trained fencesitters that way. And thanks a lot for not writing down what the technically trained people of the time found particularly convincing or particularly imminently testable, so that only people who heard the informal conversations know what happened, and we end up doing he-said-she-said oral history a few years later.

Lambert's version of what he heard might be plausible if there was some technical or historical reason why stratospheric temperatures are much better known than tropospheric temperatures. Evans' simplification might be plausible given that humans considering a positive change are commonly more impressed by a positive-change bullet point. Or I can sorta reconcile both their reports by imagining a hallway conversation like this: "Look, we've nailed that the troposphere will warm with rising CO2 concentration. Nailed it." "Dude. The earth's temperature can warm on a long timescale for all sorts of reasons. Looks like that's happening now. So the troposphere is going to warm too, duh." "The troposphere is going to warm *and* the stratosphere is going to cool. Find another reason that explains *that*." In that case Evans' recollection seems OK, and Lambert's attempt to rectify Evans' incorrect version is not absolutely incorrect, especially if he walked in late or didn't really grasp the significance of the first part of the conversation.

Phil writes:

Cool. I read the post, and the update, decide to look up the various details (largely from Climate Audit et al. - isn't there a Douglass paper relevant to this? tropos/stratos, they all sound like aftershaves) and find I've been pre-empted in some detail by a whole bunch of other sceptics. And we haven't even got into the Lomborg variations yet.

Ben Kalafut writes:

Tim Lambert pwns so I don't have to. A rule of thumb that would serve Arnold Kling well is to stick to peer-reviewed papers. If someone has to publish a novel argument in The Australian instead of in the Physical Review, there's very clearly something wrong.

I'm happy to see Monckton publishing in something scientists read, even if he's not quite a scientist himself and it's not a peer reviewed journal. Give it a few months and see what reactions turn up.

And I'm still curious as to Kling's motives. How much reading has he done, that he can take a strong position contra the IPCC consensus instead of saying "that's over my head, I don't know"? In the absence of any scientific reason for his position, what else could be "making him tick"?

Ben Kalafut writes:

Most curious, though, is Kling's apparent lack of shame, in that he refuses to make a distinction between totally meritless and borderline meritorious "dissent".

Tim Lambert thoroughly discredits Evans's argument on his own Deltoid 'blog. That should have been the end of the story. Why knowingly spread nonsense?

Dan Weber writes:

The question is whether we should play it safe by carbon taxing the planet into maintaining large amounts of poverty,

We don't need to put economy-crushing carbon taxes into place. We could just replace income taxes with carbon taxes. At least in the United States, the economy as a whole would do better, since we would be taxing consumption instead of production.

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