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.
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.
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:
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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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
I wonder who the peer reviewers were. I don’t suppose the experts like Dr Spencer were asked to review it. Pal review anyone?
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.
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/
REPLY: Thank you, I’ve added a link to the main body for you. – Anthony
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
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. …
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…
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.
Positive feedback at work:
http://upload.wikimedia.org/wikipedia/en/5/5c/TacomaNarrowsBridgeCollapse_in_color.jpg
If positive feedback is present in our climate, why didn’t this happen to our atmosphere billions of years ago ?
The preponderance of evidence indicates negative feedback.
For a detailed examination of cloud feedback see: http://www.appinsys.com/GlobalWarming/Clouds.htm
“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.
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.
About as clear as night and day.
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!
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
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?
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.
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.
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!
I agree with James Sexton. RC is a poisonous, selectively censorious and unacceptable platform for scientific discussion. Move it elsewhere.
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!
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.
Anthony / Mods: I suggest you X-out Dessler’s phone numbers.
The community is rightly blamed, because this atrocity passed peer review.
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………
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!