The Dessler Cloud Feedback Paper in Science: A Step Backward for Climate Research

How’s this for “rapid response“? This rebuttal comes out at exactly the same time the press embargo lifts in Science. We were able to obtain advance copies of the Dessler paper, plus Dr. Spencer had seen it as a poster at the recent A-Train satellite symposium. – Anthony

Update: Dessler responds here at Real Climate and makes the full paper available here at his TAMU website.

Screencap - As the article appears in Science Magazine, note embargo

2PM EST, December 9th, 2010 by Roy W. Spencer, Ph. D.

How clouds respond to warming – the ‘cloud feedback’ problem – will likely determine whether manmade global warming becomes either the defining environmental event of the 21st Century, or is merely lost in the noise of natural climate variability.

Unfortunately, diagnosing cloud feedback from our global satellite observations has been surprisingly difficult. The problem isn’t the quality of the data, though. The problem is figuring out what the cloud and temperature behaviors we observe in the data mean in terms of cause and effect.

So, Andy Dessler’s (a Texas A&M climate researcher) new paper appearing in Science this week is potentially significant, for it claims to have greatly closed the gap in our understanding of cloud feedback.

Dessler’s paper claims to show that cloud feedback is indeed positive, and generally supportive of the cloud feedbacks exhibited by the IPCC computerized climate models. This would in turn support the IPCC’s claim that anthropogenic global warming will become an increasingly serious problem in the future.

Unfortunately, the central evidence contained in the paper is weak at best, and seriously misleading at worst. It uses flawed logic to ignore recent advancements we have made in identifying cloud feedback.

In fact, the new paper is like going back to using only X-rays for medical imaging when we already have MRI technology available to us.

What the New Study Shows

So what is this new evidence of positive cloud feedback that Dessler has published? Well, actually it is not new. It’s basically the same evidence we published in the Journal of Geophysical Research.

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 conclusions?

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, it lets in more sunlight, which then amplifies the warming. That is positive cloud feedback in a nutshell.

Table 1 from Dessler's paper, publsihed in Science Dec 10th.

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 feedback?

A Step Backwards for Climate Science
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 can not 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 see a type of tumor that X-rays cannot reveal.

What we showed was basically a new diagnostic capability that can, to some extent, separate cause from effect. This is a fundamental advancement – and one that the news media largely refused to report on.

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

Sound strange? Welcome to my world.

We even replicated that behavior see in the satellite data analyzed with phase space analysis — our ‘MRI for the climate system’ – by using a simple forcing-feedback climate model containing negative cloud feedback. It showed that, indeed, when clouds cause temperature changes, the illusion of positive cloud feedback is created…even when strongly negative cloud feedback really exists.

Why Dessler Assumed We Are Wrong
To Dessler’s credit, he actually references our paper. But he then immediately discounts our interpretation of the satellite data.

Why?

Because, as he claims, (1) most of the climate variability during the satellite period of record (2000 to 2010) was due to El Nino and La Nina (which is largely true), and (2) no researcher has ever claimed that El Nino or La Nina are caused by clouds.

This simple, blanket claim was then intended to negate all of the evidence we published.
But this is not what we were claiming, nor is it a necessary condition for our interpretation to be correct. El Nino and La Nina represent a temporary change in the way the coupled atmospheric-ocean circulation system operates. And any change in the atmospheric circulation can cause a change in cloud cover, which can in turn cause a change in ocean temperatures. We even showed this behavior for the major La Nina cooling event of 2007-08 in our paper!

It doesn’t mean that “clouds cause El Nino”, as Dessler suggests we are claiming, which would be too simplistic and misleading of a statement. Clouds are complicated beasts, and climate researchers ignore that complexity at their peril.

Very Curious Timing

Dessler’s paper is being announced on probably THE best day for it to support the IPCC’s COP-16 meeting here in Cancun, and whatever agreement is announced tomorrow in the way of international climate policy.

I suspect – but have no proof of it – that Dessler was under pressure to get this paper published to blunt the negative impact our work has had on the IPCC’s efforts.
But if this is the best they can do, the scientists aligning themselves with the IPCC really are running out of ideas to help shore up their climate models, and their claims that our climate system is very sensitive to greenhouse gas emissions.

The weak reasoning the paper employs – and the evidence we published which it purposely ignores! – combined with the great deal of media attention it will garner at a time when the IPCC needs to regain scientific respectability (especially after Climategate), makes this new Science paper just one more reason why the public is increasingly distrustful of the scientific community when it comes to research having enormous policy implications.

===============================================================

Abstract:

Clouds and Climate:
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.

Article #10: “A Determination of the Cloud Feedback from Climate Variations over the Past Decade,” by A.E. Dessler at Texas A&M University in College Station, TX.

Contact: A.E. Dessler at +1-979-862-1427 (office phone), +1-979-220-4513 (mobile phone), or adessler@tamu.edu (email).

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124 thoughts on “The Dessler Cloud Feedback Paper in Science: A Step Backward for Climate Research

  1. Positive feedback?! For sure, that’s why we’ve seen skyrocketing temperatures for the last 15 years and ocean heat content since 2003 going through the roof!

    /sarcasm off

  2. I wonder who the peer reviewers were. I don’t suppose the experts like Dr Spencer were asked to review it. Pal review anyone?

  3. So -let me get this straight.
    Dessler says that when it’s hot, that causes the clouds to vanish, and so the increased heat causes it to be a sunny day.
    Spencer says that when there are no clouds, it’s sunny, and so more likely to be hot.
    I’m not sure we need peer review to decide on this one.

  4. I believe….

    Even though no tipping points have ever been reached in the past, and
    elevated CO2 levels were immediately followed by rapidly falling temperatures,
    and there has never been run away global warming no matter how high CO2
    levels have been….

    …I believe

    Man made CO2 is different. It might look exactly like a “C” and two “O”s,
    but it’s different. Only nature can tell, and you can’t fool Mother Nature.

    This time it’s different, because it’s man made.

    ….I believe

  5. Most of us here at this site know the alarmists are wrong. A graph posted a few days ago compared temperatures in the last few decades versus number of weather stations. The graph echoed something we heard at the 4th International Climate Symposium held in Chicago, sponsored by the Heartland Institute. One of the presenters was a climate scientist desirous of furthering the science and wanted the basic data to build on our [mis]“understanding” of global warming and climate and so on. He noticed the deleted weather stations, and observed that the deleted ones were always the coldest ones. That of course turned him into a skeptic.

    The WUWT graph showed minor bouncing around of temperatures in the 70’s and 80’s along with a stable number of weather stations. Then in 1990, the number of stations dropped, and more were deleted the following few years. At that time, the was a sudden jump in reported temperatures.

    There was no real warming in the 20th century. But there was promotion of ethanol that drove up world grain prices and starved poor people, mostly in Africa, to death, emissions controls on US cars that resulted in flimsier cars that killed thousands of people in accidents and immense harm to the world economy (including the decline of the American auto industry). The fraudsters are murderers, and should be jailed.

    But then there is the vast climate “science” community, most of whom were simply duped, and have a REAL job to do to find out what actually does drive El Ninos and other weather phenomena. While Man cannot adjust the climate YET, by the end of this century, and probably much earlier, we WILL. It is important that we get it right. Calling life-creating gases “pollutants,” and going 180 degrees on what are optimal temperatures will not cause the Life of Earth to thrive. Only true beliefs can do that.

    We need to get the actual climate science community, including disciplines such as biology, ecology, geology, able to face and deal with truth. And that requires a miracle called TACT. Tact is how you tell somebody they have been screwing up such that you mostly make them right and they end up happy with themselves. Thus they have the strength to make the corrections that will make them better.

    UNtactful–your stupidity and dishonor makes you a murderer.

    Tactful–you have learned a lot about science, including its self-adjusting nature. Now you can help us determine optimums. A good scientist is cautious in his Discussion section, and we want to be careful that we understand what we are doing before we make policy recommendations. …

  6. The staging of the release of this paper–and the scientific shortcomings within it–are indicative of why more “mainstream” scientists are questioning exaggerated AGW claims and are pillorying the IPCC…

  7. lol, I agree, if this is the best they can do, put a fork in them, they’re done.

    Earlier this summer, I felt a cool breeze and it chilled the sweat on my body. So much so, I got a bit cooled, fortunately, a cloud came between me and the sun and I started to warm again.

  8. Positive feedback at work:

    If positive feedback is present in our climate, why didn’t this happen to our atmosphere billions of years ago ?

  9. “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.”

    That confuses me. Isn’t positive feedback a circular process? So they are saying cloud changes cause temperature changes which cause cloud changes which cause temperature changes…(higher temps => fewer clouds => even higher temps => even fewer clouds => what, it’s still getting hotter? => not a cloud in the sky this year…) You can start at any point in the circle and you’ll end up in the same place – a hot planet with no clouds.

    Even negative feedback, a resistance to further change in once direction, has causation in “both directions”. Clouds affect temps and temps affect clouds. But with negative feedback your circular process has you bouncing around a stable equilibrium point. (higher temps => more clouds => temps fall a bit => clouds dwindle a bit => temps rise a little => a few clouds come back…). Start at any point in the circle and you’ll end up, eventually, bouncing around that same equilibrium point, which will be different for different environments.

    Are these cloud studies (including yours) attempting to state that cloud feedbacks are net positive/negative for the entire globe, or in every climate region, period? I can understand summing up all of the global regions for a net positive/negative, but if the studies are stating that the feedback is the same for every region then that is counter-intuitive to me. A temperature increase to a desert surrounded by mountains would have the same cloud feedbacks as a temperature increase to a Brazilian rain forest, or the arctic circle, or the antarctic? How much water are you heating up along with earth/air? How does the water flow through that local region of the hydrosphere? How does surface albedo change? Deserts have high barriers to cloud formation, while rainforests generate clouds (the transpiration highway). I really don’t see how cloud feedbacks could be shown as always positive/negative in every temperature increase scenario.

  10. Let’s publicly invite Andy Dessler to come here and have a polite conversation with Roy Spencer about the science.

    It’s a reasoned public forum, Andy, frequented by perhaps millions of intelligent interested people. We’d all appreciate the clarity such a conversation would bring.

  11. Like Willis’ post, this one suggests to me that these climate geniuses are simply adding to their publication lists by rehashing their stale ideas, while ignoring new findings that are contrary to theirs. That ain’t science, BTW.

    Anyway, it probably makes little difference. As noted by Lord Monkton (yesterday?):

    “Many worshipers in the Church of “Global Warming” here in Cancun have begun to realize that the game is up, the science is in, the truth is out, and the scare is over.”

    What a great statement!

  12. Andrew Dessler says:
    December 9, 2010 at 11:26 am

    For an alternative look at Roy’s comments, see my response at: http://www.realclimate.org/index.php/archives/2010/12/feedback-on-cloud-feedback/
    +++++++++++++++++++++++++++++++++++++++++++++++++++++++

    Andrew, first, please don’t take offense to the familiar term of address, it’s simply that I don’t know the appropriate formal term, such as Dr. or Prof, or Mr…….

    Secondly, I’ve been to RC. I’ve attempted to engage in a few discussion there. They either heavily edit my statements and questions or simply don’t post them at all. Please use a more open forum to post rebuttals and engage in discussions.

    Many thanks,

    James

  13. Andrew,

    First, let me congratulate you on the “cordial exchange” with Dr. Spencer. I think science would benefit greatly if there were more exchanges in this manner.

    I’ve read your response and I’ve only a couple of points to make.
    1) Models don’t predict anything. Modelers do the predictions expressed by the models.
    2) In your version of cloud dynamics as far as retaining more heat the hotter the planet gets, the more heat retained by clouds…….where is the stopping point? Obviously, there is no run away heating up, or we would have already achieved melt down by now. It isn’t plausible to think it hasn’t ever been warmer than today. If it has, what changed the dynamics of heat retention? Why do you think it won’t occur again?

  14. So Dessler is claiming that warm weather causes clouds to go away, whereas the common experience is that clouds going away causes warm weather. Indeed, when Dr Spencer showed this exact point, my reaction was: well duh!

    If we lived in normal times, Dessler’s claim would be laughed out of academia. Alas, we do not live in normal times – Kafkaesque at best.

  15. The IPCC are right because they have to be right, therefore because the IPCC are right we know that the statement that the IPCC is right, is right because the IPCC said it!

    So we have conclusively proved that the IPCC are right and so anyone who argues with the IPCC must be wrong.

  16. Dr A Burns says: “If positive feedback is present in our climate, why didn’t this happen to our atmosphere billions of years ago ?

    It’s man-made positive feedback silly!

  17. I agree with James Sexton. RC is a poisonous, selectively censorious and unacceptable platform for scientific discussion. Move it elsewhere.

  18. Some people are claiming that Spencer is wrong because his theory does not fit the global climate models…

    Neither does the actual real earth!

    I ventured to the realclimate blog to take a look-see and, even as my finger hovered over the mouse button, I hesitated as I knew I would lose an IQ point or two reading their comments.

    Oh dear, they were worse than I thought. Ad homs, “he goes against the model”, “he is not a scientist” etc…

    All very predictable and all very wrong. At least there are less comments on that blog, than on this one.

    It is obvious to anyone with a neuron firing that clouds create a negative feedback to surface temperatures. I have never been roasting hot on a sunny day and thought, OH NO A CLOUD! NOW I’LL BURN!

    Sheesh!

  19. Lemme see: cosmic ray enthusiasts claim that more cosmic rays cause more clouds that cause cooling by increasing the albedo. So it seems that all bases are covered, we can have any which way we want, just pick your [current] fave.

  20. Anthony / Mods: I suggest you X-out Dessler’s phone numbers.

    To Dessler’s credit, he actually references our paper. But he then immediately discounts our interpretation of the satellite data.

    Why?

    Because, as he claims, (1) most of the climate variability during the satellite period of record (2000 to 2010) was due to El Nino and La Nina (which is largely true), and (2) no researcher has ever claimed that El Nino or La Nina are caused by clouds.

    This simple, blanket claim was then intended to negate all of the evidence we published.
    But this is not what we were claiming, nor is it a necessary condition for our interpretation to be correct. El Nino and La Nina represent a temporary change in the way the coupled atmospheric-ocean circulation system operates. And any change in the atmospheric circulation can cause a change in cloud cover, which can in turn cause a change in ocean temperatures. We even showed this behavior for the major La Nina cooling event of 2007-08 in our paper!
    ……………………
    The weak reasoning the paper employs – and the evidence we published which it purposely ignores! – …, makes this new Science paper just one more reason why the public is increasingly distrustful of the scientific community when it comes to research having enormous policy implications.

    The community is rightly blamed, because this atrocity passed peer review.

  21. with warming being exacerbated as clouds trap larger quantities of outgoing infrared radiation
    =========================
    More incoming energy than outgoing….

    No clouds during the day, and clouds at night would do it.

    I guess timing really is everything

    Wonder why this has never happened before? not ever, never, nada………

  22. ONe thing that worries me about climate science is the frequency with which results are reported that are smaller than the error term. When I studied my physics, 0.54 plus or minus 0.74 would not have been regarded as indicating anything. I heard a similar reaction form an old lag in Antarctic science who remarked that they should have thrown out the hockey stick at the outset because none of the variation in the graph exceed the error bars provided. Could a practising scientist please explain to my why a result smaller that the error term merits a scientific publication!

  23. I was moderated out at RealClimate.. I wanted clarification, thats all, as it was not clear to me what the e-mail exchange between Dessler and Spencer actually said, since what is presented is an abridged version(apparently). Here is what I asked for:

    Ed_B says:
    Your comment is awaiting moderation.
    9 December 2010 at 4:26 PM

    “We assumed it was clear that this was short a paraphrase of the much longer chain of email exchanges linked to”

    I was under the impression that the link above(in RC) gave me a full reading of the e-mail exchange. Could Mr Dessler provide 100% of what was said by both parties?

  24. Good exposition, Anthony. At least the warmers are attempting to explain the effects of cloud on climate, and not just human carbon emission, although they will say that there is positive feedback always. And they will always invite ridicule and skepticism from the independent minded researchers and scientists.

  25. Wait, really? The response to a new method for determining a feedback is/was:

    1 – most of the climate variability was due to El Nino and La Nina.
    2 – no researcher has ever claimed that El Nino or La Nina are caused by clouds.

    Really? That’s not a response, that’s a straw man the size of the wicker man put in the wrong place with fake fire painted on. It’s like they just don’t want to learn any new math so their science gets better for it.

    C’mon climatologists, math isn’t that friggin hard, go learn some linear algebra and statistics.

  26. The ONLY way to characterize complex feedbacks is through analyzing the data phase space. Any paper that claims to make any statement regarding complex feedbacks that does not employ phase-space analysis, does so to be deliberately misleading.

  27. Dr Spencer, there was a paper by a team of IPCC faithful and Jouzel/Le Treut colleagues Cattiaux et al. 2010 in GRL that is supposed to explain why winters should be colder but are not because of global warming. This paper uses NAO flow-analogues at 500hPa levels and compare them to statistically correlated surface temperatures and O miracle, detects the sugnature of GHG global warming!
    This acrobatic pseudo-demonstration was just released ahead of Cancun and finished that fact that 2009/2010 European winter would probably be the coldest to be experienced in the 21st century… of course until winter 2010/2011 they should have added but that was going against the script… But it does not stop Jouzel or any Meteo France propagandist to quote this paper to try deflecting the bitting cold off their warmists’ shoulders.
    So there is plenty of bad science opportunistically published…

  28. The warmistas are basically afraid of that we live in an unstable regulator.

    Nature has proven again and again that the regulator is very very stable.

  29. Looks like Real Climate is using Dessler to light up a counter fire to the huge blow the refutation of Steig et al. 2009 has dealt the Team and the IPCC zealots…

    BTW: Notice how “Maple Leaf” is commenting right off the bat at RC? A stalwart at deepclimate… Yep, instead of working at finally getting his PhD in an institute paid for by a retired Canadian oilman, this student keeps insulting scientists on blogs, as he did with Judith Curry recently…

  30. Interesting comments at Fenton Communications,

    Eli Rabett (Joshua Halpern) says:
    9 December 2010 at 2:56 PM

    Hi Andy,

    This is but another example of how climate scientists are being played by the denialists. You attempted to discuss the issue with Spencer as if he were only doing science. But he is not. He is doing science and politics, and he has no compunction about sandbagging you.

    There is no gain to you in trying to deal with people like Spencer and Lindzen as colleagues. They are not trustworthy.

    …People such as Lindzen and Spencer have to be shown a cost to their two faced behavior, and the first step is to stop treating them as honest colleagues.

    What a nice guy Mr. Halpern is.

  31. u.k.(us) says:
    December 9, 2010 at 2:16 pm

    This all seems to be rather unsettling.
    =======================================================
    How so? Please note the points made here and the lack of response. (Crickets chirping)
    Eyes Wide started with a great comment, (albeit a bit sarcastic) Nothing.
    Steeptown asks about the review process.
    David C…..pretty much the same.
    At that point Andrew Dessler pops by to redirect the conversation or the lack thereof to RC.
    latitude pipes in with his usual witted insights.
    Lady Life Grows gives us a different, but not incorrect, view.
    danj questions the timing of the release.
    I added more sarcasm but hopefully a point not lost………
    and so it went….. several more by several others. Good points, biting sarcasm, invitations to engage……..nothing.
    Respectful questions were asked, salient points made, Leif even popped by to give his 2 cents.
    Others even tried to engage at RC……..how’s that working out Ed_B?
    Apparently, a character named Robuk only had a pejorative to add to the conversation and couldn’t think of anything else clever.
    Nothing………. more cricket chirping. They’ve lost. Receding back into the cocoon. Sure, they’ll emerge again after yet another metamorphosis, but the current one is done.

  32. Sorry, I had to laugh…at this in the RC comments:

    This hilarious pronouncement about “honest colleagues” is from people that can’t even bring themselves to use their own names when pontificating on the honesty of others that do.

  33. Anyone that thinks heat causes clouds to disappear has never lived in the tropics.

    When there is sufficient moisture, heating produces clouds, which produces cooling. Otherwise the tropics would be the hottest place on earth, which they are not. The hottest places are in the subtroppical zones.

    Feedback appears positive only when water is restricted.

  34. During an eclipse the sun is blocked and the umbra undergoes noticeable cooling.
    Why not measure the rate at which the temperature drops and then rises during an eclipse, along its track, and compare the two rates of change to the amount of clouds?
    If clouds do cause a positive feedback that cloudy skys will cool more slowly and return to their previous level quickly.
    If clouds have a negative feedback then the cooling will be more rapid and re-heating will be slow.

  35. I have tried and tried to understand the logic in this paper by Dessler. I failed.

    My observations are that when a cloud obscures the sun it gets colder. At night when it is cool, clouds usually mean it keeps warmer, but as it is warmer Dessler tells me the clouds should not be there, so it will get cooler or warmer, or perhaps both at the same time, who knows! I give up!

  36. The question is simply do clouds cause warming or cooling? I don’t think we have to answer the question of whether clouds are a “feedback” or an “initial driver”.

    Overall cloudiness (world average) does increase slightly when it is warmer. This is just a very small change, less than the climate models assume (and one has to ignore the ISCCP cloud project data to reach this conclusion).

    But Temperature versus Cloudiness is a monster scatterplot. In the old days of proper statistics, the professor would say this a random plot. Chart of Hadcrut3 versus all the measures of cloudiness back to 1901. Noone should be able to say clouds cause the temperature or temperatures cause the clouds.

    Do clouds cause warming or cooling is the question. I think if you take locations which receive the same amount of solar radiation at the TOA, one would find the more humid, more cloudy locations are cooler than the dryer, less cloudy locations.

    The dryer, less cloudy locations have more variation from night to day but on average they are warmer. The Sahara versus tropical rainforests is an example.

    Low, thick, convection clouds block more solar radiation than they hold outgoing longwave radiation in.

    High thin clouds, hold more radiation in than they block incoming solar radiation.

    On average, the majority of clouds are the lower, thicker type and thus, on average, they produce a net cooling. But it is not a large amount.

  37. I’m afraid I simply dont understand the thinking.
    In the summer in the UK, the mornings often start out sunny and warm(ish).
    As the day goes on, it gets hotter. Late morning, clouds start to build up. Now by the reasoning given, surely this is impossible? Yet it something seen every sunny day in the summer period here.
    Presumably we’ve all been hallucinating the cloud all these years???

    Or maybe things are completely different in the part of the world they come from?

  38. Dr A Burns says:
    December 9, 2010 at 11:40 am

    Positive feedback at work:

    Incorrect. The structure is a negative feedback system, otherwise it would be self-exciting and breakup without any particular forcing. But, the negative feedback via structural damping is weak, leading to a high Q factor at the resonant frequency. When excited by the winds at that frequency, the oscillations grew exponentially, until they reached a point great enough to induce structural fatigue and failure.

    “If positive feedback is present in our climate, why didn’t this happen to our atmosphere billions of years ago ?”

    Because there is a much stronger negative feedback overall, at the very least from T^4 radiation. In such a system, an internal minor positive feedback produces amplification rather than instability.

  39. Anthony Watts says:
    December 9, 2010 at 4:08 pm

    Sorry, I had to laugh…at this in the RC comments:……….
    ========================================================

    lol, well there is a bit to laugh at……..“…..If Dr. Dressler does nothing else than this it will be as if he did nothing.”…………. hard to argue, but kinda humorous.

    As far as the insult to the integrity of Lindzen and Spencer, that’s sad and pathetic. I’m curious as to what inconsistencies either have shown that either anonymous commenter thinks it warrants name calling. It shows the emotional maturity of a 5 y/o, but then I’ve never considered Eli nor Grant peers of Spencer and Lindzen, much less colleagues. Dr. Dressler, OTOH, has shown a willingness to engage in civil discourse(albeit, not here) without engaging in name calling. As they say, good on you, Dr. Dressler.

    In my estimation, Tamino and Eli are nothing but faceless, nameless, commenters, much like myself, except I’ve the eggs to put my name behind my writings. I’ve gone to every alarmist site I can think of, only to be denied a full voice to my thoughts, they won’t even come here knowing they won’t be denied a voice. They think they are peers to Lindzen and Spencer? Tami and Eliane can’t even find the intestinal fortitude to engage laymen and laywomen! As far as I know, neither Lindzen nor Spencer has ever shrank from adversity. But Tami and Eliane won’t come and play with the rest of us here. Anthony always gives a fair shake to alarmists and ensures their points can be made; no matter how inane the points are. I’ve much more respect for the alarmists that come here willing to exchange thoughts and ideas than ones that supposedly are experts but shrink from challenge. It makes one wonder if they ever really got through college.

  40. …he claims, (1) most of the climate variability during the satellite period of record (2000 to 2010) was due to El Nino and La Nina (which is largely true), and (2) no researcher has ever claimed that El Nino or La Nina are caused by clouds.

    This simple, blanket claim was then intended to negate all of the evidence we published.

    But this is not what we were claiming, nor is it a necessary condition for our interpretation to be correct. El Nino and La Nina represent a temporary change in the way the coupled atmospheric-ocean circulation system operates. And any change in the atmospheric circulation can cause a change in cloud cover, which can in turn cause a change in ocean temperatures.

    Another possibility, consistent with your idea, is that:

    El Nino and La Nina change cloud cover, then changed cloud cover changes temperature.

  41. Andy Dressler: Just in case my comment gets lost over at RealClimate, I’ll reproduce it here.

    http://www.realclimate.org/index.php/archives/2010/12/feedback-on-cloud-feedback/comment-page-1/#comment-194119

    *************
    Bob Tisdale says:
    Your comment is awaiting moderation.
    9 December 2010 at 8:12 PM
    Andrew Dessler: Your email correspondence with Roy Spencer included the following discussion of ENSO: “First, people have been studying ENSO for decades and my sense is that the basic theory that it is caused by changes in surface winds driving changes in ocean circulation seems to be quite successful and explains almost all of the details of the observations (e.g. the evolution of thermocline depth).”

    The increase in trade wind strength associated with La Niña events decreases total cloud amount over the tropical Pacific east of the Pacific Warm Pool, which, of course, results in an increase in DSR.

    You continued, “Second, I did a quick back of the envelope calculation and in order to get 1°C of warming in a 50m column of water in one year you need about 7W per square meter of heating. That seems a bit high. And if the warming occurs in just a few months (which it can, then the required radiative heating would be correspondingly larger).”

    Pavlakis et al (2008), in part, write in their abstract, “A clear anti-correlation was found between the downward shortwave radiation anomaly (DSR-A) time-series, in the region 7° S–5° N 160° E-160° W located west of the Niño-3.4 region, and the Niño-3.4 index time-series. In this region where the highest in absolute value DSR anomalies are observed, the mean DSR anomaly values range from −45 Wm−2 during El Niño episodes to +40 Wm−2 during La Niña events.”

    An increase in DSR of 40W per square meter far exceeds your annual requirement of 7w per square meter from your back-of-the-envelope calculation. Link to Pavlakis et al:

    http://www.atmos-chem-phys-discuss.net/8/6697/2008/acpd-8-6697-2008-print.pdf

    Regards

  42. Well I found the e-mail exchange quite satisfying. Nice to see a couple of hard working scientists trying to convince each other of their take on the data. You know, how science is supposed to work.

  43. FTA: “Phase space analysis allows us to “see” behaviors in the climate system that would not be apparent with traditional methods of data analysis.”

    Indubitably. Actually, phase space analysis is very traditional in the larger scientific community. Dr. Spencer’s phase plane analysis was elementary for a control systems engineer to read. Assuming clouds drive temperature, the counter-clockwise rotation in the Spencer-Braswell plots immediately indicates negative feedback.

    It DOES NOT MATTER if you plot the two items against one another and find that you have a positive or negative slope – that only gives you information on what the relative phase is. You can get either result with positive or negative feedback. This is the gist of Dr. Spencer’s argument, and he is inarguably correct. The weakness of Dessler’s argument is he makes no accounting for phase lead or lag. He treats the data as if the response were instantaneous. His analysis is therefore fatally flawed.

  44. ge0050

    Good on you sir. I believe your point is fundamental to understanding cloud feedback and is one of the many issues that continues to confound us when we study climate. Feedbacks are neither temporally nor spatially constant. On a blog post at a neutral site Gavin made the case that the positive feedback could be inferred from back calculating an implied feedback following the Younger Dryas. One of the issues I have with that argument is that it ignores the issue you raised. It would not surprise me at all if net water vapor feedback is positive when exiting an ice age, but this tells us little about what it is NOW.

  45. Incidentally, I posted a link to my post at 5:47 PM at RealClimate. Guess what? It’s gone. What a surprise.

  46. Thanks for you interest in my work. One thing I’d like to comment on is the question of whether clouds warm or cool. Of course clouds cool. That’s not the question. The question is whether clouds cool more or less as the climate warms. A mathematical analogy would be: we know the function is negative, what we’re trying to determine is the sign of the first derivative. What I find is that while clouds cool, and will continue to cool, they will cool less as the climate warms.

    Since there’s a bunch of criticism about my methodology, I’d like to point out that Lindzen uses basically the same approach as I do (although there are differences, e.g., he only looks at 20N-20S). Thus, I contend that, if you don’t believe my approach, then you must also not believe Lindzen. In fact, I would go so far as to say that Spencer and Lindzen cannot both be right. So who do people here believe?

    Bob Tisdale: You’re probably right about that. I put that into the e-mail without spending much time thinking about it.

  47. I was taking a walk the other morning, it was still foggy out, but I ventured on anyway. Boy did that burn! The IR bouncing back and forth from the ground to the fog was quick and intense!

  48. Anyone with any engineering experience would know that the positive feedback hypothesis is junk, as it would mean that the Earth would have fried just after birth. it clearly hasn’t.

  49. Robert of Ottawa says:
    December 9, 2010 at 6:24 pm

    “…it would mean that the Earth would have fried just after birth. it clearly hasn’t.”

    We are wasting too much space on such comments by neophytes – no offense that, I made the same mistake when I was new to the topic, too. It’s meant in a different sense than you are used to. See my comment here.

  50. Robert of Ottawa says:
    December 9, 2010 at 6:24 pm

    Anyone with any engineering experience would know that the positive feedback hypothesis is junk, as it would mean that the Earth would have fried just after birth. it clearly hasn’t.
    =======================================================

    Well, yah, but that’s not what the models told us!!!! Well, ok, it is, but we didn’t have models back then so it didn’t count!

  51. Andrew Dessler says:
    December 9, 2010 at 6:11 pm

    Dr. Dessler: I am not familiar with Dr. Lindzen’s analysis. But, as I pointed out here, your analysis is flawed. You MUST take account of the phase difference between your variables. As it is, you have produced nothing of a conclusive nature.

  52. Andrew Dessler says:
    December 9, 2010 at 6:11 pm
    What I find is that while clouds cool, and will continue to cool, they will cool less as the climate warms.
    ==========================================================
    Andrew, that seems to fly in the face of observations and temperature reconstructions.

    Most reconstructions show a fairly sharp rise, a peak, and a rapid jagged decline.

    If clouds “cool less” as the climate warms, what is your opinion as to why the planet has never had run away global warming before?

  53. Andrew Dessler says:
    December 9, 2010 at 6:11 pm

    …….. Of course clouds cool. That’s not the question. The question is whether clouds cool more or less as the climate warms. A mathematical analogy would be: we know the function is negative, what we’re trying to determine is the sign of the first derivative. What I find is that while clouds cool, and will continue to cool, they will cool less as the climate warms.

    …….. In fact, I would go so far as to say that Spencer and Lindzen cannot both be right. So who do people here believe?
    ======================================================

    Wow, Dr. Dressler, thanks for dropping by with more than a link to a place where we can’t comment. It is greatly appreciated!

    Yes, Lindzen and Spencer have different approaches. This is known. The answer to your question, for me, at least, is both and neither. I respect both for their candor and willingness to share, educate and engage. Sometimes I agree, other times, not so much. It isn’t as if people believe either are infallible. As you probably know, Dr. Spencer posts here from time to time. Often, it is simply a report of his satellite data, which is often met with many jeers. It’s natural. He comes here anyway, knowing that he will be challenged and tasked to answer questions.

    Skeptics come in all shapes, sizes and colors. For instance, I’m a bemused skeptic. I’m one that believes a bit of warming would be beneficial to the earth, and would be more than happy to show where history tells us it is. I also don’t think we’re effecting the climate much either, but its a bit of a side point for me. I tend to look beyond science but the policies enacted, well, I get a bit animated…..enough of that….

    To the science……doesn’t more heat cause more evaporation, which in turn, causes more clouds? (I’m sorry, but I like to start at the start of premises. This way there isn’t much misunderstanding.)

  54. Bob Tisdale says:
    December 9, 2010 at 5:23 pm
    Andy Dressler: Just in case my comment gets lost over at RealClimate, I’ll reproduce it here.

    ====================================

    Your comments got snarked by one of the mods over there, Bob. I hope you will publish a retort.

    Best,
    Chris

  55. 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
    ============================================================Andrew Dessler says:
    December 9, 2010 at 6:11 pm
    What I find is that while clouds cool, and will continue to cool, they will cool less as the climate warms.
    ============================================================
    So who do people here believe?
    ============================================================

    You’re making that choice a lot easier………………
    In your abstract you claim that the feedback from clouds is positive.
    In your words, you say that clouds will continue to cool, only cool less.

    Since when is cooling less a positive feedback?
    Unless you guys have re-written the English language along with climate science,
    positive feedbacks are not what you would call doing negative feedbacks less.

  56. savethesharks says:
    December 9, 2010 at 7:34 pm

    Your comments got snarked by one of the mods over there, Bob.
    ========================================================
    Shocker. Hard to imagine Bob will get to retort in any manner. Let me know if they let us start playing there, ……..after several years.

  57. So warmer air makes the clouds go away. If we heat the planet too much, it will be like Venus, full of clouds.

  58. latitude: I think Bart gave a good response to your question. While clouds provide a positive feedback that increases climate sensitivity, sigma T^4 is the fundamental stabilizing feedback that keeps the climate from running away. Of course, if a feedback is stronger than sigma T^4, then the climate will indeed runaway, but the feedbacks in our climate system are far weaker than that.

    Bart: There are good physical reasons to expect clouds and water vapor to be controlled by surface temperature w/o any lag (in monthly data). Thus, the lag zero correlation is expected to be the most appropriate. In support of this, I’ve looked at other lags and the correlations are all weaker than lag zero.

  59. latitude: If clouds cool less as the climate warms, then that is indeed a positive feedback. Remember, the feedback is a derivative, dR/dT, where R is heat trapped by clouds and T is the temperature. I’m saying the derivative dR/dT is positive … the fact that R is negative does not preclude dR/dT from being positive.

  60. latitude says:
    December 9, 2010 at 7:12 pm

    If clouds “cool less” as the climate warms, what is your opinion as to why the planet has never had run away global warming before?
    ======================================================
    Maybe we’re wording the question wrong. IDK, it seems to me, if his posit is correct, then before we were even imagined, humanity would have long been wiped from the face of the earth. Maybe he doesn’t have an answer to the question or maybe we’re not understanding his posit correctly……….Dr. Dressler?

  61. Andrew Dessler says:
    December 9, 2010 at 8:00 pm

    “There are good physical reasons to expect clouds and water vapor to be controlled by surface temperature w/o any lag (in monthly data). “

    You do not have to go on faith. YOU’VE GOT THE DATA. Go to your control systems department (the best control systems people are typically in EE) and tell them you need to perform a system identification analysis. They will explain it all to you.

  62. Before signing out…

    “I’ve looked at other lags and the correlations are all weaker than lag zero.”

    I frequently see this. You are using inappropriate analysis tools for a dynamic system. Take my advice, if you want to know the truth. Consult the experts in system ID who have been about it for decades before you climate guys ever came along.

  63. And… I assure you, there are significant lags. All I have to do is look at the Spencer-Braswell plots to see it staring me in the face.

  64. Bart says:
    December 9, 2010 at 8:22 pm

    Before signing out…

    “I’ve looked at other lags and the correlations are all weaker than lag zero.”

    I frequently see this. You are using inappropriate analysis tools for a dynamic system. Take my advice, if you want to know the truth. Consult the experts in system ID who have been about it for decades before you climate guys ever came along.
    ======================================================
    Heh, now Bart, as correct as you may be, you know how the “appeal to authority” is viewed. Some, if they can put their personal beliefs aside for a while, can ID systems on their own. Of course, it wouldn’t hurt to ask some experts along the way, but that’s the easy way!

  65. I’m surprised that nobody has commented on the scatterplot in the main figure (2). Both visually and from the r^2=2% (ie 0.02), and a slope failing a signicance test, the proper conclusion is that there is no evidence either way. Roughly from the r^2, 98% of the variance is unexplained by the regression, which explains only 2%.

    The scale in Figure 2 has negative values of T(K). Is it because of this breakthrough that it was published by Science? I think we should be told.

  66. If Spencer’s work was dismissed as he used the period 2000 – 2010 which was full of natural variability and no obvious co2 induced warming – why than does Dessler not dismiss his own analysis???

  67. Please let me cite Prof. Joni Mitchell, pioneering climatologist, who did valuable early work on clouds:

  68. Dr. Dressler,

    Congratulations on your prominent publication–pretty good for an Aggie!

    I agree with your contention that authors have no control on the precise dates of publication of their articles. Dr. Spencer was quite ungracious to suggest that there was some funny business on your part about the issue of Science in which your paper appeared. However, I’m sure that you would agree that the staff at Science was keen to get it out in the timeframe of the Cancun meeting, and the fact that it was embargoed means that they expected a rather large splash.

    My question for you: Did Science solicit your submission? In my area, it is common for Science and Nature to request submissions of work that their editors become aware of–often with the notion that they might be published to correspond with major meetings. It doesn’t mean that there’s some conspiracy afoot–it’s merely the practice of these “high impact” journals like to maximize visibility.

  69. I would think this is a pretty easy problem to solve. If there is more moisture for clouds, there is more cloud cover. If evaporation increases from forcing, there is more moisture for clouds, and there is less forcing from the sun. When evaporation decreases from less forcing because of more clouds, there is less evaporation, and so there is less cloud cover. Which leads to more forcing from the sun. Which leads to increased evaporation and more cloud cover. And so on.

    Of course, it would be nice to have some paleo-cloud data handy. Anyone know of a good dataset for paleonimbus?

  70. From Realclimate:
    ***Short paraphrase:

    Spencer: ENSO is caused by clouds. You cannot infer the response of clouds to surface temperature in such a situation.

    Dessler: ENSO is not caused by clouds, but is driven by internal dynamics of the ocean-atmosphere system. Clouds may amplify the warming, and that’s the cloud feedback I’m trying to measure. ***

    I do not see where Spencer states this explicitly.

  71. Negative feedback implies clouds will increase as the earth warms. If clouds are decreasing while the earth is warming, that would rule out negative feedback as the dominant process, even if it doesn’t prove positive feedback.

  72. Jim D, “dominant” is problematic in that context. First, you ignore lag. Second, obviously if the earth is warming all immediate negative feedbacks are being dominated at least temporarily. That doesn’t tell us anything about individual feedbacks.

  73. savethesharks says: “Your comments got snarked by one of the mods over there, Bob. I hope you will publish a retort.”

    I replied.
    &&&&&&&&&
    Bob Tisdale says:
    Your comment is awaiting moderation.
    10 December 2010 at 5:07 AM

    raypierre replied: “Sorry, not even close, and no cigar. You are ignoring the fact that to determine the effect of clouds on SST you can’t take just the downward shortwave effect and ignore the cloud greenhouse effect. The cloud greenhouse effect nearly compensates at the top-of-atmosphere, but it works its way into the surface budget through warming the atmosphere. But take heart — you are in good company in being confused about this. It was the basis of Ramanathan’s confusion in his famously wrong ‘thermostat hypothesis.’”

    Interesting. In a reply to my same comment over at WUWT, Andrew Dessler wrote, “Bob Tisdale: You’re probably right about that. I put that into the e-mail without spending much time thinking about it.”

    http://wattsupwiththat.com/2010/12/09/the-dessler-cloud-feedback-paper-in-science-a-step-backward-for-climate-research/#comment-547536

    Additionally, if memory serves me well, Pavlakis et al addressed your concerns in the paper linked above and in their earlier companion paper:

    http://www.atmos-chem-phys.org/7/2013/2007/acp-7-2013-2007.pdf

  74. Andrew Dessler says:
    “What I find is that while clouds cool, and will continue to cool, they will cool less as the climate warms.”

    Maybe in a hypothetical model. In reality, clouds are constantly moving, any slight change in the balance you are modelling is far outweighed by movement of the clouds either towards, or away from the equator.

    Please correct me if I am wrong.

    Sir, thank you for taking the time to engage in the conversation in a venue which allows free speech, it really is appreciated.

  75. So now, Spencer says he isn’t claiming that clouds are the cause of El Nino. His statement is,

    ” El Nino and La Nina represent a temporary change in the way the coupled atmospheric-ocean circulation system operates. And any change in the atmospheric circulation can cause a change in cloud cover, which can in turn cause a change in ocean temperatures. We even showed this behavior for the major La Nina cooling event of 2007-08 in our paper!”

    This statement means that clouds are a feedback mechanism in the classic sense. If clouds are to be regarded as a feedback mechanism, then Dessler’s data , showing that when temperature increases, trapping of radiation by clouds increases, shows that behavior of clouds add to the increase in temperature. This is positive feedback.

    It is true that clouds are complicated, as Spencer says, but that statement doesn’t negate the data and its interpretation by Dessler, if clouds are regarded as a feedback phenomenon. There is no logic in Spencer’s objection.

    The objection to the publication date of Dessler’s paper seems beside the point.
    It seems like whining on the part of those who don’t like the data and conclusions, and wish it would go away.

  76. Each increment of increased Clouds in a warming world provides a feedback of -5, -4, -3, …. and so on.

    In the unusual world of climate science trying to prove the theory right, this series of negative feedbacks turns into a positive feedback because -3 is not as negative as -4.

    Nope, each increment of more clouds is still a negative feedback.

    Clouds increase as it gets warmer. Clouds provide a net cooling. Therefore, clouds are a negative feedback even if they are less negative as the warming increases.

    Dessler’s formulae need to be rewritten because there has been some mistake in the mathematical transforms. It is probably because he is mixing and matching deltas with absolute values which can lead one astray if you don’t keep in context what you are actually plotting and the signs of what you are plotting.

    For example, Cloud forcing is say -40 watts/m2 but declines to -39 watts/m2 in the 2007-08 La Nina when temperatures fell to -0.3C. If you correlate the change in cloud forcing of +1 watts/m2 (a delta) against the -0.3C (which is now a simple absolute value) the correlation starts to looks like a positive feedback when it is in reality a negative one.

  77. Wayne Richards says:
    December 9, 2010 at 9:28 pm
    Citing Dr. Mitchell; so it’s finally “settled”: “ice-cream castles”, “rain & snow”, yep clouds=negative feedback. Too bad she was never peer-reviewed, ah…the ‘team’ would have never allowed this landmark work through their ‘process’. ;-)

    On a more serious note:

    Andy,
    Thank you for posting your e-mail exchange with Roy at RC. I found it encouraging that the discourse was, well, amicable, intelligent, and professional. On reading this post (and not Spencer’s blog) I didn’t get the impression that he was accusing you directly (although you deny being on the receiving end of ‘being pressured’ on the RC thread), but rather alleges that the review and publishing process (or powers that be) wanted this in time for Cancun. If you discovered that somewhere the process had been “messaged” to expedite your work being published sooner than would normally be expected, for political ends, what would your response to that be?

    I was disappointed at your “slapdowns” of Spencer on the RC thread: specifically the Cancun comment and the dismissal of his work. It gives the positive, professional tone of your email discourse a disingenuous “flavor” and denegrates your position. As a result (IMO) Spencer’s position of your method being likened to “…using only X-rays for medical imaging when we already have MRI technology available to us.” is bolstered. They also seemed as an intentionl mechanism to flagellate the regular RC crowd, and were successful.

    After reading some of the research (from IPCC, you, Spencer, Cheng, et al) on clouds as feedbacks I come away with the impression that a definitive answer is still “out-there” but stacking up in the direction of general negativity/cooling depending on region, altitude and type of clouds involved (still many unanswered questions). The arguement for causation: chicken or the egg (temp/clouds) will only eventually be answered by continuing the work, through collaboration, cooperation, and amicable discourse between researchers.

  78. Dressler states:

    “It is important to note that while a slight negative feedback cannot be ruled out, the data do not support a negative feedback large enough to substantially cancel the well-established positive feedbacks, such as water vapor, as Lindzen and Spencer would argue. ”

    Yes, water vapor is a well established positive feedback, but why does the cloud feedback have to be negative enough to cancel it out? Since Wentz showed that the models were only able to reproduce one-half to one-third of the precipitation increase (a negative feedback), it is not even clear that the water cycle viewed in total, not just the water vapor component, is a net positive or net negative feedback. Since even Dressler grants that his work doesn’t rule out a slight negative feedback, he is basically acknowledging that all the model based projections with correlated high positive cloud feedback and high total net positive feedback, might well be wrong.

    A net negative or neutral feedback leaves the well mixed greenhouse gas hypothesis accounting for less than a third of the recent warming, and contributing only about one degree C of warming over the next century. One degree C is less than the natural variation, so a decade or even thirty year period 100 years from now might well be cooler.

  79. Andrew Dessler says:
    December 9, 2010 at 8:04 pm
    latitude: If clouds cool less as the climate warms, then that is indeed a positive feedback.
    ==========================================================
    Andrew, what is the magic number then?
    Since CO2 has nothing to do with this, it’s temperature only.
    After your research, you must have found a magic temperature where clouds
    are no longer negative and they switch to positive.

    If there is no magic temperature, that can only mean that as temps go up, clouds
    become more positive, making it harder for temps to go back down.
    That would be the run-away global warming.

    Since we know that temps have always gone back down, then that would mean that
    clouds have very little, if any, effect. Or it could mean that clouds were never positive in the first place.

    What temperature would you think is that point?
    At what temperature would you consider clouds no longer negative but positive?

  80. Since anything I post at RC is removed (or never makes it) almost immediately I have to make my comment here.

    I read this statement by Dr Dressler in his comment at RC, “A positive cloud feedback loop posits a scenario whereby an initial warming of the planet, caused, for example, by increases in greenhouse gases, causes clouds to trap more energy and lead to further warming. Such a process amplifies the direct heating by greenhouse gases. Models have been long predicted this, but testing the models has proved difficult. ”

    I don’t believe he is correct in stating that “models have long predicted this (positive cloud feedback)”. I think the models are constructed with positive cloud feedback ‘built in’. The models can hardly be said to ‘predict’ something that is built into the equations as an assumption. That would be like saying the ‘model’ that contains the equation ‘2+2 = 4′ ‘predicts’ that 2+2 = 4 isn’t it?

  81. Climatologists are amazing. They talk about positive feedback as if it was just an other measure of something. But positive feedback has consequences. Amplifiers saturate, servomechanisms speed up, reactors blow up, temperatures run away, things break.

    Where are the consequences of positive feedback on the earths climate. The earths climate is stable. Even huricanes end in a whimper not a bang. There has never been a thermal runaway. Ice age yes but thermal runaway no. Untill climatologists can demonstrate the consequences of positive feedback, they should go back to school and study servomechanisms.

  82. I’m sorry for my simplicity, but isn’t it true that the suns energy being centrally located in a area of earth causes a high radiation and convection system stacking up into the atmosphere to become a high pressure area. No clouds.

    The lower pressure areas allow water vapor to form and condense into clouds. Lots of clouds.

    So when the high pressure collapses and allows a lower pressure system to move in, the heat transfer to the atmosphere is slowed and trapped as water vapor(clouds). There is always water vapor in the air and when the sun is at it’s minimum in winter water vapor will form into ice crystal in the air with clear sky’s. A lowering of atmosphere allow nuclei to enter and form as a rain drop or a snowflake.

    Clouds can temporarily trap earths radiant heat on its surface AND block out the heating energy reaching earths surface from the sun.

    El Nino or El Nina is just a easy out to explain wrong predictions from a flawed CPU model. I`m sick of this BS (bad science). Man made/almost all natural CO2 is a flea on the suns back when influencing the warming on earth. Your explanation/modeling is just as wrong as the others saying the opposite. Water vapor is the 99.999% main GHG, what else influences earth more? Pfft.

    Claiming you can model clouds when you have absolutely zero knowledge of how they are created is beyond belief. Modern science has become a GIS modeling program, how sad.

  83. Bill Illis says:
    December 10, 2010 at 4:55 am
    Nope, each increment of more clouds is still a negative feedback.
    Clouds increase as it gets warmer. Clouds provide a net cooling. Therefore, clouds are a negative feedback even if they are less negative as the warming increases.
    =======================================================
    Thanks Bill, that’s what I was working towards.

    Andrew seems to be looking at each cloud. Where as temps increase, each cloud
    has less negative feedback.
    Warmer will create more clouds.
    Where each cloud could possibly be slightly less negative, according to Andrew, but the accumulation of more clouds would have a greater net cooling.

    It could be a possibility that the entire surface of the planet becomes covered in one big cloud.
    Would that be positive, as Andrew likes to call it, or negative?

  84. Dr. Dessler, Apologies for misspelling your name above. I hope you continue to participate here, since realclimate is highly censored. Regards.

  85. 85-90: ENSO avg. 0 >> cloud cover unchanged.
    90-00: ENSO positive >> cloud cover reduced
    After 00: ENSO avg. 0 >> cloud cover unchanged

    How can that be positive feedback?

  86. Dr. Dessler,

    “Of course clouds cool. That’s not the question. The question is whether clouds cool more or less as the climate warms. ”

    In what way is this statement not self-contradictory? “Less cooling,” however awkward the language, means a net increase in temperature, inarguably. By positing a theory that clouds cool less as the climate warms, and then failing to explain why we would not inevitably have arrived at a cloudless hot planet very shortly after the first day warmer than the previous day, you have contradicted yourself. If these two phenomena were coupled with unchecked amplification, life could not exist. In other words, we all better hope and pray that clouds cool at least as much, if not more, when “climate” warms.

    Do one of Einstein’s “thought experiments” about this. Automatic Control is well-understood, well-documented, and easy to study. Every engineer who reads this will say the same thing, at least to himself or herself.

    Keep this up and I am going to start in with the Aggie jokes…

  87. I’ve been using Real Climate to try to persuade Andrew Dessler to provide information that would enable a reasonable comparison to be made between his paper and Spencer and Braswell 2010, but it has been very frustrating. Although a couple of my questions were accepted, I felt that the responses were deliberately evasive. I persisted, and although I was polite and staying focused on the scientific issues, my posts were repeatedly rejected. Meanwhile, Real Climate supporters continued to successfully post offensive character assassinations against both Spencer and Lindzen. This is the first time I’ve tried posting there, and frankly I find it difficult to understand what the people running Real Climate believe they achieve by this kind of behaviour.

    In any case, here is my rejected question, just in case Andrew is still hovering around here:

    Andrew Dessler:

    Thank you for your response to my question #43 – I very much appreciate your answers. You suggest that SB 2010 argues that it is not possible to identify a climate feedback from the observed variations. But from my reading, what they say is that you are likely to obtain an incorrect answer with the method used in your paper. Instead, they suggest that a better approach is to use a phase space plot in which linear striations represent the feedback. They also provide a simple theoretical model that demonstrates why this should be so.

    I apologise for persisting with this issue, but I want to understand better and I think this difference in calculational approach is important. As far as I can tell, the difference in approach has nothing particularly to do with clouds or ENSO variations – it is simply that there are two different ways of analysing the satellite data in order to obtain an estimate of feedbacks. Would you explain please, why you prefer the method of analysing the data used in your paper to the method described in SB 2010?

    Although I haven’t had an answer to this yet, I did notice that Andrew provided a reply to Fred #56, which I think is relevant:

    Fred: I would not categorize Spencer’s 2010 paper as an approach; it’s more of an argument. Basically, he’s saying that if you don’t know what’s causing the temperature change, determining feedbacks is impossible. My argument with Roy is not over whether that’s correct, but over my contention that, with ENSO, we know what’s causing the temperature change. Spencer is not describing a new or different way to determine the feedback.

    As far as I know (please correct me someone, if this is incorrect), the substantive parts of Andrew’s reply to Fred are both untrue:

    [1] Andrew says that SB 2010 is “saying that if you don’t know what’s causing the temperature change, determining feedbacks is impossible.” But my understanding is that SB 2010 is suggesting you can estimate feedbacks by examining the phase space plot and that the paper provides a theoretical reason why that should be so.

    [2] Andrew says that SB 2010 is “not describing a new or different way to determine the feedback.” But again my understanding is that SB 2010 is doing precisely that by using the phase space plo

  88. Once again – we get models and studies on individual components of our climate and attempt to control for them by refusing to acknowledge either how they interact or that we don’t know.

    Amazing. The logic of Dr. Dresler’s theory does indeed suggest a hot cloudless planet, which should have already been achieved, long, long ago, if we accept as fact that the earth has been warmer than today within the last 10,000 years.

  89. The summary to all this is really very simple. Whatever controls the energy content of the ocean on such a planet as our earth is the primary driver of climate. And the answer is SWR from the sun, either increasing or decreasing at the ocean surface, is the primary driver of our planets energy budget. To assume that an effect which increases the LWR in the atmosphere at the expense of a reduction in SWR entering the oceans, controls the climate and earths energy budget, is to claim that a small puff of wind can reverse the direction of an ocean liner under throttle. Besides the seasonal changes, it is changes in cloud cover and location that primarily affect how much or how little SWR enters the ocean. An increase in LWIR can cause a short term increase in atmospheric heat content, but over a longer term the reduction in SWR heating the ocean will produce mitigate as negative feedpack to the increased hydrologic cycle.

    It is a curious thing, the more the CAGW crowd tries to state that the hidden heat is in the oceans and it just takes an ever longer time to manifest, the more they diminish the role of CO2 and LWR relative to SWR. If the energy within the oceans residence time is very long, then any change in the energy most capable of heating the oceans, SWR, will have a far greater effect then the short term energy of LWR within the atmosphere. The residence time of energy within a system is in direct relationship to its heat sink capacity.

  90. A comment I left at Dr. S’s site on this:

    Andy asks, “… what is the limit that Global Temperatures could hit assuming co2 continues to increase at the predicted rate? Or will temperatures rise indefinitely?

    I am of course writing this from the UK which currently resembles a large Popsicle.”

    Well, best estimates are that we could barely reach 1600 ppm CO2 if we burned all the fossil fuel on the planet at once.

    Dr. S, Lindzen & Choi, and others are converging on a sensitivity around half a degree C per doubling. So:

    400 ppm — 0 (now)
    800 ppm — +0.5
    1600 ppm — +1.0

    Answer: About one degree C. more than now. Hardly enough to melt a popsicle. If the sensitivity turns out to be 0.7, then a degree and a half.

    And for an idea of how dangerous 1600 ppm of this dreadful pollutant is, that’s less than a quarter of the US Navy’s limit for CO2 concentration in a submarine.

  91. What level of evaporation was assumed? I am referring to Dr Lindzen’s presentation to Congress. The GCM’s assume 1-3% per degree F. The observations suggest a much larger 5.7% per degree (Wentz, et al.). Surely, this value is fundamental to determining the sign of the feedback term. I believe, Dr Dessler’s paper is using empirical data and making no assumptions about this value. However, this data would be skewed BECAUSE the observations occurred over La Nina waters IMHO. Surely, the initial temperature of the oceans would effect whether warming resulted in more or fewer clouds because this would effect the local adiabatic lapse rate. This could be investigated by checking the apparent feedback versus local SST.

    Another comment, you can have positive feedbacks without runaway warming. A net positive feedback can still exist without a closed loop gain greater than one. However, significant positive feedbacks would result in an unstable output response. It is a valid point to observe that that is not reflective of the planet we live on. I believe this fact is the source of Lindzen’s statement that it is “intuitively implausible” that the earth’s climate is dominated by positive feedbacks.

  92. Bill Illis says:
    December 10, 2010 at 4:55 am
    “Nope, each increment of more clouds is still a negative feedback.
    Clouds increase as it gets warmer. Clouds provide a net cooling. Therefore, clouds are a negative feedback even if they are less negative as the warming increases.”

    No. Feedback is a sensitivity parameter, a partial derivative, rather than a direct quantity. Think of an easy feedback system in your home: the toilet. Within the tank is a float, which senses the level in the tank, and progressively applies greater pressure as the level rises, eventually closing the valve and keeping the water at a set level. This is a negative feedback – the closing valve counteracts the inrush of the water by applying increasing valve resistance to the flow.

    Now, consider a case where this is reversed, and the float actually opens the valve more as the level rises. At every level before it is fully open, the valve is partially closed, so it is impeding the water all the time (same as your saying the clouds are cooling all the time). But, this is a positive feedback, because as the level rises, the valve’s resistance to the flow decreases.

    Eventually, this will lead to overflow, unless perhaps you have a bigger float which acts to close the valve once the level reaches beyond a certain level. This would be a very strange design for a toilet, granted, but that is an analogy to how the larger negative feedbacks in the climate system would prevent a positive feedback from causing instability (or overflow, in this analogy). But, the level would undoubtedly reach a higher level with the positive feedback of the first float than with the negative feedback from it. In such a way, we see that positive feedback internal to a larger negative feedback acts to amplify the output.

  93. A quote from the paper to help everyone get their head around this:

    ” … the net effect of clouds is to reduce the net flux of incoming energy at the top of the atmosphere (TOA) by ~20W/m2, as compared to an otherwise identical planet without clouds. The cloud feedback refers to changes in this net effect of clouds as
    the planet warms. If, as the climate warms, cloud changes further reduce net incoming energy, this will offset some of the warming, resulting in a negative cloud feedback. If, on the other hand, cloud changes lead to increases in net incoming energy, then the change will amplify the initial warming, resulting in a positive cloud feedback.”

    So, Dessler’s conclusion is that as the planet warms, the clouds will let in more incoming solar energy (even though the same paper shows they increase as the planet warms).

    I guess they thin out by a larger percentage as the planet warms. Which is something that Dessler should have proven/shown rather than rely on CO2-based climate model results.

    And I have to question Dessler’s number of -20 watts/m2 above because clouds represent more than half of the planet’s Albedo or let’s say at least -55 watts/m2.

    That alone means there is a serious error in the paper and how the data was processed.

  94. Interesting article from the arXiv blog

    http://www.technologyreview.com/blog/arxiv/26105/?p1=Blogs

    Essentially, Dallas and Vassilicos are saying that micrometer scale turbulence accelerates cloud formation and triggers rain showers.

    That’s an interesting, although not entirely unexpected result that should lead to better weather forecasts. Perhaps more significantly, it could also have a big impact on climate models. Clouds have a big effect on the amount of light Earth reflects back into space. Being able to better calculate when they form is important.

    And it plugs an embarrassing hole in our understanding of one of the most basic atmospheric phenomena.

    Wonder how much this finding affects the climate models people like Dr Dessler use. If this really is a “new” piece of information, then the GCMs are (obviously and always) wrong.

  95. “Amazing. The logic of Dr. Dresler’s theory does indeed suggest a hot cloudless planet, which should have already been achieved, long, long ago, if we accept as fact that the earth has been warmer than today within the last 10,000 years.”

    “Dessler”, the man has a name of his own of course.

    Why, yes. This apparently is a problem of language. What exactly do these climatatologists understand the word “Feedback” to mean? Anyone in a junior high auditorium experiencing the awful trill/scream of auditory “feedback” knows firsthand what it means. What is the the other meaning? Seems to have something to do with the “Climate Sensitivity” being larger or smaller than 2.0 degrees C, but in what way exactly?

    Terms are important. Is Climatology a science at all???????????????????

    In my business, these people would be laughed out of the room as rank amateurs, not allowed to speak after the first idiotic thing they said….

  96. It means the same thing thought their use of positive and negative is inconsistent with the actual theory as well as function. Few acually demonstrate even basic understanding of how it works.

    Mark

  97. when you look at the basics of thermodynamics the electron is what is moving.

    A cloud is nothing more than a resistor in a circuit. it can only react to changes of polarity, EMF, and it works in both directions. Clouds are a result of not the reason for the change.. but can result in a slower change to equilibrium.

  98. However, Clouds can become a factor if excited by other forces… Galactic rays… which ionize water and form clouds can enhance the cooling by thickening the clouds and increasing the reflective properties..

  99. I admit being in an area with which I am technically unfamiliar. But the discussion, while interesting and educational, sounds more like an argument about the question: which came first, the chicken or the egg? Even moreso, it sounds like Dessler is taking the same data as Spencer is using and putting his own personal spin on it. Which is more evidence that the science remains quite unsettled. It also proves that two scientists are very much like two attorneys: when you talk to them, they give you at least three different opinions.

  100. CORRECTION:
    original=Clouds are a result of not the reason for the change..

    Corrected= Clouds are normally present and act as a buffer of changes in drivers.

    when i reread my previous post i had made an error in description. the only result of outside factors on clouds is increasing or decreasing the coverage and intensity of buffering. clouds are an intermediary in the energy transfer and can act as a positive or negative feedback mechanism.

  101. Re Bill Illis says:
    December 10, 2010 at 5:32 pm

    Bill, even more important then the amound of energy reduced is the wavelength. Clouds and water vapor induce tremendous solar spectrum modifications, water vapor on a clear day reduces the SWR by 20%, and considerably more in the tropics on clear day. At its most basic only two things can effect the energy content of any system in a radiative balance. Either a change in the input, or a change in the “residence time” of some aspect of those energies within the system. Residence time of energy correlates to heat capacity. The greater “residence time” of the oceans allows a far larger increase or decreases relative to any change in input then an equivalant change in the shorter road of the atmosphere. A simple traffic analogy will work to illustrate this.

    On a highway if ten cars per hour enter the highway, and the cars are on the road for ten hours before exiting, there will be 100 cars on the road and as long as these factors remain the same the system is in balance. If you change the INPUT to eleven cars per hour, then over a ten hour period the system will increase from 100 cars to 110 cars before a balance is restored and no further increase occurs. The same effect as the increase in INPUT achieves can be realized by either slowing the cars down 10% or by lengthening the road 10%. In either case you have increased the energy in the system by ten percent by either increasing the residence time or the input.
    3. Now lets us take the case of a very slow or long road with the same input. Ten cars per hour input, 1000 hours on the road, now you have ten thousand cars on the road. Now lets us increase the input to eleven cars per hour just as we did on the road with a ten hour residence time. Over a 1,000 hour period we have the same 10% increase in cars (energy) How ever due to the greater capacity on that road the cars, (energy) have increased 100 times, (1,000 verse 10 ) Any change in the input or the residence time on this 1,000 hour road will have a 100 times greater effect then on the 10 hour road.

    This is cogent to climate in that the 10 hour road is the atmosphere, and the 1000 hour road is the oceans. Any change into the ocean input is going to have a FAR GREATER long term effect then an equivalent change in the residence time of energy in the atmosphere. The reduction in SWR induced by clouds will, over time, overwhelm the increase in LWIR clouds induce within the atmosphere.

    Share your thoughts on this please. Thanks

  102. Clouds are a result of not the reason for the change..

    Which highlights the fact that they are not a positive feedback. Clouds are a result of evaporation, block the incoming SWR, which results in less evaporation, and then less clouds, which results in more evaporation, more clouds, blocking incoming SWR, resulting in less clouds…

    Still, I would say that Spencer’s point that this could appear as a positive feedback is understandable, wouldn’t you? If you start looking in a year where there is less evaporation, you would see that there is more heat, and so more clouds, and be confused.

    If, however, you were to study cloud behavior over the poles or deserts, it’s pretty obvious that clouds thrive on evaporation. Also clear from studying the tropics is that evaporation and cloudiness will, after a turn, lead to less clouds. So, again, where does Dessler separate the chicken from the egg?

  103. To highlight what I mean by referring to poles or deserts, the dryness of air in these places means very few clouds, moisture seems the dominant condition. A fact that is freckled onto the shoulders I left in the Mojave sun a bit too long. Still, that is why I referred upthread aways to paleonimbus data. It would solve quite a bit, but I fear it goes in the logical direction that clouds seek to regulate forcings in order to maintain the liquid state of water, and no more or less. How’s that for a thought? You’re both right, under the right circumstances.

  104. Check the inverse relationship between low level, and medium level clouds. If you see their functions in terms of low level clouds keeping cold nights warmer, and medium level clouds reducing daytime maximums, it makes good sense of observations in terms of the response to changes in solar forcing :-

  105. As Aynsley Kellow (Dec 9th, 1:43 PM) noted the uncertainty given by Dessler is so high as to make his results virtually meaningless.

    Quoting from Dessler 2010, “The slope of this scatter plot is the strength of the cloud feedback, and it is estimated by a traditional least-squares fit to be 0.54 [+/-] 0.72 (2s) W/m2/K (the slope using the MERRA [data] is 0.46 T 0.75 W/m2/K).”

    The scatter plot looks like a shotgun blast. The fact it has any measurable trend at all is astonishing.

    Dessler showed that there might be a very small positive feedback, at some times and in some places). But there also might not be. Or the feedback could be negative.

    dT

  106. Orchestrated public relations.
    As stressed in Crichton’s ‘State of Fear’ so long ago.
    Silly plot line and characters. But I immensely respect anyone who attempts to offer rational thought to the masses beyond the blogosphere.

    jc

  107. I’ve been following Spencer, Lindzen and others on this crucial topic with great interest so when I heard of this paper by Dessler, I was quite interested. As noted by others, the extremely poor correlation in Dessler’s paper corresponding to Figure 2A with an r^2 of only 2% seems to really discredit this work. Any slope at all seems to be driven by a few points on the left. It seems that this work is a house of cards. The almost zero correlation suggests that the assertions and conclusions about cloud feedback and sensitivity are virtually worthless. The poor correlation seems to lead me back to the conclusion that Spencer’s work is on the right track and that the phase space and lags he shows provide a much better explanation. This coupled with the questions as to why we haven’t seen a runaway to a cloudless hot planet really puts Dessler’s work in doubt. The reliance on the blackbody radiation term to keep this from occuring seems like a desparate attempt to cover up the serious problems here. I have to wonder why Science did not include Spencer as a reviewer. Spencer as a reviewer could have asked Dessler to use his phase space technique to see if a better correlation of this data could have been obtained. This would have helped compare the two explanations much more effectively and, if there is any merit to Dessler’s claims, this would have helped make his case much more effectively.

    Why Science did not include Spencer as a reviewer is a big question mark and suggests to me, after climate gate, Briffa gate and the hockey stick fiasco, we still do not have a fair peer review process and that there is a strong bias for keeping the AGW hypothesis alive no matter what. When will we be able to trust these people. I fear never. I will continue to watch developments and see how this ends up but right now, Dessler’s work looks like another red herring that has been promoted by the AGW orthodoxy in academia and the media.

  108. Dessler says his analysis technique is the same as that used by Lindzen and Choi. Can somebody explain how they arrived at very different conclusions if Dessler’s claim is true? I don’t see it.

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