I’ve Looked at Clouds from Both Sides Now -and Before
by Roy W. Spencer, Ph. D.
…sometimes, the most powerful evidence is right in front of your face…..
I never dreamed that anyone would dispute the claim that cloud changes can cause “cloud radiative forcing” of the climate system, in addition to their role as responding to surface temperature changes (“cloud radiative feedback”). (NOTE: “Cloud radiative forcing” traditionally has multiple meanings. Caveat emptor.)
But that’s exactly what has happened. Andy Dessler’s 2010 and 2011 papers have claimed, both implicitly and explicitly, that in the context of climate, with very few exceptions, cloud changes must be the result of temperature change only.
Shortly after we became aware of Andy’s latest paper, which finally appeared in GRL on October 1, I realized the most obvious and most powerful evidence of the existence of cloud radiative forcing was staring us in the face. We had actually alluded to this in our previous papers, but there are so many ways to approach the issue that it’s easy to get sidetracked by details, and forget about the Big Picture.
Well, the following graph is the Big Picture. It shows the 3-month variations in CERES-measured global radiative energy balance (which Dessler agrees is made up of forcing and feedback), and it also shows an estimate of the radiative feedback alone using HadCRUT3 global temperature anomalies, assuming a feedback parameter (λ) of 2 Watts per sq. meter per deg (click for full-size version):
What this graph shows is very simple, but also very powerful: The radiative variations CERES measures look nothing like what the radiative feedback should look like. You can put in any feedback parameter you want (the IPCC models range from 0.91 to 1.87…I think it could be more like 3 to 6 in the real climate system), and you will come to the same conclusion.
And if CERES is measuring something very different from radiative feedback, it must — by definition — be radiative forcing (for the detail-oriented folks, forcing = Net + feedback…where Net is very close to the negative of [LW+SW]).
The above chart makes it clear that radiative feedback is only a small portion of what CERES measures. There is no way around this conclusion.
Now, our 3 previous papers on this subject have dealt with trying to understand the extent to which this large radiative forcing signal (or whatever you want to call it) corrupts the diagnosis of feedback. That such radiative forcing exists seemed to me to be beyond dispute. Apparently, it wasn’t. Dessler (2011) tries to make the case that the radiative variations measured by CERES are not enough energy to change the temperature of the ocean mixed layer…but that is a separate issue; the issue addressed by our previous 3 papers is the extent to which radiative forcing masks radiative feedback. [For those interested, over the same period of record (April 2000 through June 2010) the standard deviation of the Levitus-observed 3-month changes in temperature with time of the upper 200 meters of the global oceans corresponds to 2.5 Watts per sq. meter]
I just wanted to put this evidence out there for people to see and understand in advance. It will be indeed part of our response to Dessler 2011, but Danny Braswell and I have so many things to say about that paper, it’s going to take time to address all of the ways in which (we think) Dessler is wrong, misused our model, and misrepresented our position.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Reading along.
But, but, but – this work hasn’t been approved by The Central Committee on Climatology!
How dare you subvert the normal processes of ‘science’ and let the general public see it without their sanction. Surely there must be at least three yers of process to go through before anything like this comes into the public domain – if at all.
And to publish it at WUWT as well! You are a heretcic and an apostate and are hereby excommunicated from the One True Way. Cast into the outer darkness forever.
/sarc
The post looks great, and must be simple for those who are involved in this research and are familiar with all the language. Many of us, probably most of us, are not engaged in this particular discipline but as citizens of Earth we are interested to understand the “Big picture”.
When someone puts out a new new “revelation” about something, especially in such a controversial subject, it would be good if the “man in the street” could understand it, and understand why it never came up before. It is the simple ideas that make the biggest impact on the majority of people so I hope these ideas can be presented so that non-scientist types can get to grips with them. Science speak is great for scientists but this issue is not just about some accademic/scientific theory in a lab that has no effect on the outside world, it effects the whole planet and everyone on it.
For us that work in the weather we understand the “Cloud Effect” very well. From inside a climate controled enviroment through glass the effect is less. With no windows reality is realy out of perspective. When you take into account all the types of clouds and their microenviroments around the world at a given time to even think about any part being normal is out there. To even average over a period of time and call it normal climate leaves a lot.
Looks like it’s getting harder and harder to say that an increase in a trace gas is the cause of all climate ills…… Yet Australia’s dopey Labor Party is about to tax its entire population for producing it.
The Australian Labor Party….. The political party that taxed the air we breathe.
That’s a good cue for enjoying this cartoon by Josh once again…
http://wattsupwiththat.files.wordpress.com/2011/09/josh_spencer_teaching_dessler.jpg
Ha, Milk in coconuts at last.
Kindest Regards
Given that the list of matters it sounds like you intend to take Dessler to school on…I mean to rebutt him on…could it be possible to ask that you publish in installments? Say two or three a week for as long as it takes?
For us “interested but I’m not a PhD candidate” types, we can’t absorb the thing as fast as you can write it, and we need time to catch up. Besides, by stretching it out, you put Dessler in a real bind. He can’t cherry pick one or two minor items out of the whole paper and then claim he has debunked the whole thing (a favourite tactic of the Team I’ve noticed), he has to respond to each piece as it comes out…our look like he doesn’t have a response at all. Best of all though, when defending himself on Chapter 1, he has to respond with facts that very well may rob him of his defense in Chapter 4, and so on.
Besides, after having the media and the public at large at their beck and call for so long, watching a member of the Team twist in the wind for a few weaks instead of just one article…seems like justice.
Wolfgang Wagner, are you paying attention? The demigod you bowed down to has sent his flag bearer to do battle on his behalf, to defeat SB11, the task he assigned to you and which you failed to accomplish. You’re of little use to him now, you’ve lost credibility with the CAGW croud and the skeptics alike. Judith Curry has done the world a great service by moving from blind faith to crtitical but fair comment. You too can do some good and be remembered in the history books for doing the right thing. Or for being a patsy. Your call.
I think I’ve never heard so loud
The quiet message in a cloud.
===========
Temperature, humidity, clouds, atmospheric pressure,… etc. are the internal inter-dependent components of the climate system, with all feedbacks automatically factored in by nature, the laws of physics and the strong modulation by the annual insolation cycle.
Only the external factors can be the long term causes of the climate oscillations. CCL.
This looks like, REALLY important.
So important that it needs spelling out in ultra-simple laymans language, appealing to our common experience, plus graphics. So important that it needs clear c-y-a arguments too, to answer Skeptical Science etc.
Jo Nova? Mark Hendrickx? Minnesotans 4GW? Lord Monckton? Anyone?
One detail that piques my curiosity: although cloud-as-feedback is clearly vastly smaller, time-wise it seems to lead slightly. Is this an artefact of the graph’s imprecision? Or could this be in reality more evidence for Svensmark, that clouds are determined by cosmic ray input which correlates with solar output – which might cause a slight delay in cloud effects?
The big picture here is that it is only over the last decade that data specifically intended to accurately measure key climate values has become available, I am thinking of measuring incoming/outgoing radiation at top of atmosphere and ocean heat content.
So rather than the science being settled, it is only just getting started.
What Spencer is saying is that clouds are an important forcing in their own right.
i wait with baited breath. But when a scientist tells me that heat will travel, by whatever method, from cold to hot as Dr. Spencer told me in an email, I view all his work with suspicion.
Way ta go Doc Spencer! I got cha back, My silly little theory may explain why,
http://ourhydrogeneconomy.blogspot.com/2011/10/ipcc-down-welling-radiation-violates.html
More on the big picture;
With prior datasets not specifically intended to measure the key climate variables, the AGW crowd could argue that you have to look at long time series to see the climate change signal because the data is noisy.
Thats not the case with the new datasets and conclusions can be drawn from much shorter time series. Spencer draws his conclusions from 3 months of data.
BTW, I came to a similar conclusion from the Argo ocean heat content data. The month to month changes can’t be accounted for by the forcings the AGW crowd use and there has to be another forcing at work and that can only be clouds (more specifically something that affects the phase change from vapor to liquid droplets).
Writing a paper and getting published are two different things , the ‘Team’ will be on the case big style so it would not be a surprise to find this papers ‘review’ moves at pace suitable to keep it out of any IPCC consideration. And I would expect another record turn around in a answer to it.
I’m not sure, but I think Dallas is on to something. I saw Roy’s stuff and immediately thought of him. Check it out.
==============
go put your stuff on Roy’s blog, Dallas. Some person of discernment is eventually going to face the blackboard and look at it. I’ve mentioned previously that Good Cartoons drive out Bad Cartoons. I reason backwards that since Trenberth is missing something, maybe this is it.
=========================
I think we need to be careful with terminology, especially with what is meant by “forcing”. The IPCC describe forcing as a change in the radiative budget that is independent of the natural system (my interpretation – could be misunderstood). This would make the following causative events to be forcings by IPCC definition: CO2 buildup, changes in solar irradience, aerosols, changes in planetary albedo. These things are not held to be forcings: changes in cloud cover, changes in water vapour levels.
The IPCC say that these things are the result of forcings and are described as feedbacks. Prima facia, this seems reasonable if we assume that changes in cloud cover and water vapour are controlled totally by temperature which itself is the result of forcings. We could argue (as many have) that cloud cover is effected by factors other than temperature. Svensmark cosmic ray hypothesis is the best known example. In this case, cloud cover is effected by events outside the forcing-temperature-feedback cycle already mentioned. By any definition, this would make changes in cloud cover a forcing.
However, unless I am missing something, I can’t see how Dr. Spencer’s CERES graph has anything to say on cloud forcing as it is dealing with the net effect of many different causative factors. So I don’t think the question is settled.
I wish the folk who post `important’ posts on this blog would take the time to draft a simple, introductory paragraph, explaining in simple terms the significance of whatever it is their post is about.
This post is (with respect) another example of `in-house’ musing that fails to inform the generally interested follower of this blog.
Ok, if there is no intention to inform the educated general public, that’s fine. Just that the Bear thought that was one of the main aims of a popular blog, such as this.
Too whiny? Too much trouble?
M.A.Vukcevic says:
October 9, 2011 at 1:05 am
“Only the external factors can be the long term causes of the climate oscillations. CCL.
Does that mean in Cloud Capiche Land ???
“I view all his work with suspicion.”
good that is how all statements of this fact or that theory should be taken, it’s only when you start to do it to one side or one source that the trouble starts !
Thanks Kim, the word is out. All I need is one undergrad with a fresh mind, computer that works and is fluent in southern, I’m good to go!
I left the equation on Roy’s blog and asked for some emissivity information at 600mb, there seems to be a bump around -25 to -30C according to my calculations, ~0.71 ballpark. to fine tune the coefficients, e seems real close, don’t know about a and b, pretty complex PDQ relationship. Doable, if I had someone that hasn’t killed as many braincells as I have.
😉 Very interesting… I had never thought the clouds would have an impact on the Eco-system, even if they fly higher at night and lower during the day. I am curious about how you will address the paper and what the comments and opinions about the paper will conclude and how you will find a conclusion. Will you prove Dessler wrong or has Dessler proved right?! I am also interested in your response to this. I believe I have learnt more about clouds, storms and the CERES-measured global radiative energy balance charts then I ever learnt from Geology in school. I look forward to hearing more!
All the Best,
Ezzy 🙂