Clouds and Climate Confusion


I see a climate computer model - what do you see?

Clouds have bedeviled scientists' efforts to figure out how much warming might result from adding carbon dioxide to the atmosphere. Science is publishing today a new study by Texas A&M atmospheric scientist Andrew Dessler that finds that clouds contribute to future warming. As Science's press summary describes Dessler's results:

On a global scale, clouds presently influence climate in a way that cools the planet. But, they will lose some of that cooling capacity as climate warms, according to a study that supports current ideas about how atmospheric carbon dioxide affects global temperature. Clouds can potentially have both positive and negative feedback effects on climate, and this is responsible for much of our uncertainty about the amount of warming that will be caused by increasing concentrations of carbon dioxide in the atmosphere. It's generally agreed that overall this feedback is positive, with warming being exacerbated as clouds trap larger quantities of outgoing infrared radiation, but so far we have only a general idea of this effect. Andrew Dessler has estimated the actual magnitude of the feedback effect by analyzing ten years of satellite data on the flux of radiation through the top of the atmosphere. He concludes that the feedback effect is indeed positive and of a value that agrees with the canonical range of estimates of how much warming will occur for a doubling of atmospheric carbon dioxide.

This study contradicts the findings of University of Alabama in Huntsville climate researchers Roy Spencer and William Braswell published earlier this year in the Journal of Geophysical Research. Intirguingly Spencer and Brasswell used the same data as Dessler: Spencer stands by their results and responds:

What is the new evidence of positive cloud feedback that Dessler has published? Well, actually it isn't new. It's basically the same evidence we published in the Journal of Geophysical Research earlier this year,…

Yet we came to a very different conclusion, which was that the only clear evidence of feedback
we found in the data was of strongly negative cloud feedback. But how can this be? How can two climate researchers using the same dataset come to opposite onclusions?

The answer lies in an issue that challenges researchers in most scientific disciplines – separating cause from effect.

Dessler's claim (and the IPCC party line) is that cloud changes are caused by temperature
changes and not the other way around. Causation only occurs in one direction, not the other.
In their interpretation, if one observes a warmer year being accompanied by fewer clouds,
then that is evidence of positive cloud feedback. Why? Because if warming causes fewer clouds, that would let in more sunlight which then amplifies the warming. That is positive cloud feedback in a nutshell.

But what if the warming was caused by fewer clouds, rather than the fewer clouds being caused by warming? In other words, what if previous researchers have simply mixed up cause and effect when estimating cloud feedbacks?

What we demonstrated in our JGR paper earlier this year is that when cloud changes cause
temperature changes, it gives the illusion of positive cloud feedback – even if strongly negative cloud feedback is really operating!

I cannot overemphasize the importance of that last statement.

We used essentially the same satellite dataset Dessler uses, but we analyzed those data with
something called 'phase space analysis.' Phase space analysis allows us to "see" behaviors in the climate system that would not be apparent with traditional methods of data analysis. It is like using an MRI to spot a type of tumor that X-rays cannot see.

What we showed was basically a new diagnostic capability that can, to some extent, separate
cause from effect. This is a fundamental advance.

he Dessler paper is like someone publishing medical research that claims the tumors do not
exist because they still do not show up on our latest X-ray equipment … even though the new
MRI technology shows that they do exist!

We even replicated the behavior seen in the satellite data that was analyzed with phase space
analysis — our MRI for the climate system – by using a simple forcing-feedback climate model containing a negative feedback component. We demonstrated that the satellite data Dessler analyzed are actually showing negative cloud feedback, not positive feedback.

Let's hope that further research will some day soon resolve this crticial modeling issue.

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  1. Settled science!

    1. Ever see that scene in “Scanners” where that dude’s head exploded?

  2. Of course they see the causality as going one way. They have to. That is what their tenure and their grants and their entire careers depend upon. It is called confirmation bias.

    1. But the government funds it, therefore it is completely unbiased research. The only research we need to be suspicious of conflict of interest is that which is funded by private groups that are not left-leaning.

    2. John,

      Look at the name again:

      Roy Spencer

      Does that name look familiar?

      Perhaps it is time you apologized for all the nasty things you have said about him and his work measuring global temperatures using satellite data.

  3. Awesome post, Ron… It’s been seven years since I got my masters in atmospheric science and then left the field for the dark underbelly of law school, but I’ve always felt that you can’t really rely on long-term climate models until you understand cloud feedback. I’ve emailed my friends still in the field to get their take on it but this could be the most significant research to come out on the subject since, well, since we thought the globe was cooling.

    1. What was the name of that (Danish?) scientist who had a heart attack on film during a discussion at Copenhagen? Anyway, as I recall, his focus is on possible solar contributions to warming, and is therefore naturally concerned with cloud effects.

      Okay, I just stopped being lazy and hit up the google for you: his name is Henrik Svensmark.

  4. atmospheric scientist Andrew Dessler that finds that clouds contribute to future warming

    At least he didn’t find that they contribute to past warming. So he’s probably on the right track.

    1. Bless you, Tim.

  5. If Gregory House has taught me anything, it’s that you don’t automatically trust what the MRI tells you any more than you should the results of an X-ray. The clouds probably have lupus.

    1. Its never lupus.

      1. Ha ha! Fight lupus!

      2. its idiosyncratic lupus!
        in medicine putting “idosyncratic” in front of something is the equivalent to the economist’s ‘one the one hand, on the other.’
        For me, I just say I don’t know.

    2. You moron. It’s sarcoidosis.

    3. Parasite.

    4. The clouds are probably lying about their medical history so as not to piss off their girlfriend.

  6. Look! That cloud looks like Al Gore!

    1. Speaking of climate confusion and the Goracle, do what I do– Go get all the free carbon offsets you want:

      Then you can go about your life guilt free!

    2. Aye, very like a whale

  7. You say critical modeling issue, I say pfftt. Can we please defund all of these studies before someone decides it’s possible to centrally plan the climate?

  8. This is illustrative of my broad argument against radical “crash fixes” including economic curtailment and geo-engineering. PhDs at a couple of respectable universities can’t even agree on what direction the feedback loop is based on the same data-set. Maybe we shouldn’t rush off tilting at multi-trillion dollar windmills just yet.

    1. I still think it’s hilarious they are trying to model a system that is literally a textbook example of an inherently chaotic system.

      1. Eh. There are lots of examples of chaotic systems that have emergent order. When you don’t know the direction of your feedback, though, control systems are useless.

  9. did not, did so, did not, did so, did not, did so, did not, did so,did not, did so, did not, did so, did not, did so, did not, did so,


  10. The climate change circle jerk gravy train will never end, will it.

    1. circle jerk gravy train


    2. Is that why the gravy is lumpy?

  11. I saw a rocket fly through the clouds yesterday. Not that that’s relevant to anything posted here.

    1. I shot an elephant in my pajamas.

      1. Did you shoot him for wearing your pajamas?

        1. Of course. How he got into my pajama, I’ll never know.


  13. he Dessler paper is like someone publishing medical research that claims the tumors do not
    exist because they still do not show up on our latest X-ray equipment … even though the new
    MRI technology shows that they do exist!

    You mean a “mainstream” climate scientist, publishing shoddy work that serves to confirm his own views of AGW?

    I am shocked, SHOCKED!

  14. I must say that Spencer’s explanation of the differing results of his colleague was not the most diplomatic.

    Kick ‘im again, Spence!

    1. I believe ‘poopy do do head’ is well established in the literature, and prefaced with ‘regret’ as in ‘I regret my esteemed collegues disageeing with reality, but he is a poopy do do head.’

  15. Let’s hope that further research will some day soon resolve this crticial modeling issue.

    You need to go back and read what Spencer wrote and reread his study.

    The issue has already been resolved…just some poeple do not want to admit it.

    also: typo correction “crticial” should be “critical”

  16. Somebody better tell NASA, I just sat thru an 18 minute TED lecture on how positive cloud feedback is going to doom us all.

  17. Something that makes the Cost savings of Obama Care look like settled science.

  18. Something that makes the Cost savings of Obama Care look like settled science.

  19. Let’s see, two scientists say negative cloud feedback and one scientist says positive cloud feedback. Gosh, according to AGW standards, that means the consensus is for negative cloud feedback and the science is settled. (And that’s without resorting to any Aggie jokes.)

  20. Before man invented walked the earth it was much colder and it was much warmer.

    So how is it that man is the determining factor in the direction climate change?

    And why is warmer worse than colder? Or do the AGW types erroneously think climate never changes on its own.

  21. I’ve looked at clouds from both sides now, cause and effect and still somehow, it’s clouds delusions I recall. I really don’t know atmospheric science at all.

    1. damn niffty Carol King…uh, no. Hmmmm …Joan Collins? ….
      Well, anyway, nice songplay

  22. Time for more self-important libertarians and conservatives to claim global warming is settled science! oh, how is that going for you Mr. Bailey….

  23. Cue Joni Mitchell, pioneering climatologist:

  24. One more reason why climate models are currently severely inadequate as a basis for any real world decisions. Of course that should have already been painfully obvious, when those models failed miserably to hind cast current climate data.

  25. New NASA model: Doubled CO2 means just 1.64?C warming…..s_warming/

  26. “It is like using an MRI to spot a type of tumor that X-rays cannot see.”

    That’s really a shockingly bad metaphor given that his alleged improvement isn’t in data collection but in how the data was analysed. More like finding a clever new way to process the X-ray data and thereby make them reveal more detail.

    I’ll be interested to read what other scientists have to say about this phase space analysis of his. It didn’t come up much as far as I recall in the email exchange between Dessler and Spencer that is linked to from Real Climate.

  27. Whatever happened to Chad?

    Shouldn’t his punk ass be showing up about now?

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