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.
Actually Mr. Moderator, If you multiply the K&T DWLR, 321 by the TOA emissivity of 0.61, their budget will match and they will find the ~24Wm-2 missing in the atmosphere. Simple mistake. Using a surface frame of reference it is obvious, well, to me anyway. If K&T would check we could move move on to more exciting stuff 🙂
Lucy Skywalker says:
October 9, 2011 at 1:07 am
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?
What is also needed is a graph showing what the CERES data should look like if the IPCC/AGW feedback hypothesis was true. Having shown the hypothesis it can then be compared to reality and falsified.
This would also be an extremely powerful tool when dealing with ‘policy makers’. “Look – this is the graph that would be seen if the IPCC models were correct. But this is the actual measurements from the CERES satellite put up to measure the real world data. The CERES real world measurements do not match the model predictions – therefore the IPCC models are incorrect as are any decisions based on those models.”
The simpler this can be done the better – preferably in a one page executive summary to the larger paper.
I may not have understood Dr. Spencers paper but if I am being told that Long Wave radiation accumulates under clouds and is then somehow forced back down to the surface of the earth and this radiation results in an increase in the temperature at the surface, I’m sorry but I just don’t believe it, however,
The albedo, i.e. the amount of solar radiation reflected back out to space, of the earths surface is given as 30% of total solar radiation. Increased cloud cover decreases solar radiation reaching the earths surface, that’s a given. Increased cloud cover also increases the amount of solar radiation (reflected from the surface) ‘trapped’ by clouds. This in turn causes solar radiation ‘trapped’ by the cloud to be reflected back towards the surface of the earth. The result is an increase in the amount of Solar radiation absorbed by the earth when clouds are present, meaning that the albedo of the troposphere is reduced when clouds are present. As reflected solar radiation is equal to solar radiation directly from the sun there is a possibility that this reflected solar radiation could travel back down, however, until evidence to prove that the Second Law of Thermodynamics is wrong, Long Wave radiation, being energy lower (colder) than Short Wave (hotter) cannot travel from an area of lower energy, i.e. the cloud to an area of higher energy, i.e. the surface of the earth.
As a member of the general public I agree with other comments that to get the facts across to more people explanations in simple English are needed.
John Marshall says:
October 9, 2011 at 1:53 am
i wait with baited breath. But when a scientist tells me that heat will travel, by whatever method, from cold to hot
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You mean the way that Travesty Trenberth says that heat travels from the cold deep ocean to the warm shallow ocean? And he didn’t say it just to me, as Dr. Spencer apparently communicated just to you.
As a few have commented, could we have a summary in layman’s language? As I read it Roy is saying outgoing radiation bears no correlation to surface temperature so some other factor like clouds is affecting matters.
But is there any evidence that cloud cover is changing, is any change correlatable to radiation, what is causing such change and is cloud cover increasing or reducing temperatures?
Regarding the “second law” arguments being made here against Spencer, they are off topic. My suggestion for those who disagree with him on that is to read the appropriate thread at SkS: http://www.skepticalscience.com/argument.php?a=164 and if you have a point of disagreement with a comment in the thread or a new argument, then add it to the thread. Please read the thread first although it is long and somewhat repetitious. Or read the Judy Curry thread http://judithcurry.com/2010/11/30/physics-of-the-atmospheric-greenhouse-effect/ But in event, try to refrain from bringing it up any time Spencer writes a post on a different topic.
“John Marshall says:
October 9, 2011 at 1:53 am
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”
John, you know that matter radiates photons as a function of its temperature and emissivity.
Cold objects radiate less energy than hot objects, if they have the same emissivity.
Take two equally sized nearby objects with the emissivity, one at 100K and one at 400K, They will both emit photons and both absorb photons, the cold object will receive photons from the hot object and the hot one will receive photons from the cold one.
In terms of the overall exchange of energy, heat, in the form of photons, will travel from the hot body to the cold body. This heat transfer is the sum sum of the fluxes, energy input – energy output. The hot body loses more heat than it gets from the cold body and the cold body gains more heat than it transfers to the hot body.
Heat is transferred in both directions, but the overall transfer is in one direction.
Dr. Spencer,
It looks to me that the graph you show here is a combination of the graphs 1A and 1C in Dressler’s 2010 paper, in your graph delta-Ts is just multiplied by the constant lambda. Dressler says about this delta-Ts: “Also plotted is an ENSO index (23), and the close association between that and delta-Ts verifies that ENSO is the primary source of variations in delta-Ts.” and
“Obviously, the correlation between delta-Rcloud and delta Ts is weak (r2 = 2%), meaning that factors other than Ts are important in regulating delta-Rcloud.”
It seems to me that you’ve reached the same conclusion as Dressler, in that there is a low correlation between the radiative forcing at the TOA and the delta-Ts. Am I correct ?
TBear Said: “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.”
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Absolutely. I very much appreciate the hard work of Dr. Spencer and others who open their minds to the possibility that the “consensus science” view is far from the final answer.
Since the matter of “global warming” has become very much a political matter that has engaged the minds of non-scientific people across the globe, it is incumbent upon the reporters of new climate science achievements – such as WUWT – to cast the technical scientific discussion in language the common man (ladies, too!!) can understand.
Many thanks for all you do, Good People.
I am afraid that I agree with Lucy Skywalker when she says This is “So important that it needs spelling out inultra-simple laymans language…”
Those here at WUWT can probably figure out what is meant by this VERY important statement by Dr. Spencer.
“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.
To me, and I certainly maybe wrong, this says the IPCC models predict radiative feedback. However the actual radiative feedback measured by CERES does not come anywhere close to matching ANY of the climate models predicted radiative feedback.
The conclusion is that the models have got it wrong. In fact they have it SO wrong there is absolutely no correlation at all.
If I screwed that up how about someone correcting it in SIMPLE language.
A lot of confused comments here, and one guy even advertising SKS; so here’s an SKS antidote.
http://wattsupwiththat.com/2010/08/05/co2-heats-the-atmosphere-a-counter-view/
And another one, Dr. Spencer’s Box experiment, for the LWIR backradiation non-believers.
Roy Spencer, The Box, measuring back radiation
http://www.drroyspencer.com/2010/08/help-back-radiation-has-invaded-my-backyard/
Looking at the big picture since the 1950s with two major shifts at around 1975 and 2000 I think the primary cause of changes in the amount of solar energy getting into the oceans is variability in the behaviour of the global surface air pressure systems under combined solar and oceanic influences.
That makes the jet streams either:
i) Move towards the poles and/or become more zonal for reduced global cloudiness.
ii) Move towards the equator and/or become more meridional for increased global cloudiness.
That is how the system input varies to the extent observed.
The potential feedbacks are effectively overwhelmed by those changes in system forcing.
Vince Causey says:
Excellent summary of the issue.
I’d add that science is about competing theories. Introduce new evidence and you shift the relative likelihood that any theory is correct.
So I’ll take issue with your last paragraph. Producing evidence that an existing theory is incorrect is unrelated to that evidence supporting a competing theory.
What lies between is ‘we don’t know’.
“So important that it needs spelling out in ultra-simple laymans language, ”
Try this:
The changes in input (forcings) to the system (represented by variations in the amount of solar shortwave getting into the oceans) are far larger than ALL the feedbacks combined and so completely overwhelm the feedbacks.
Thus the feedbacks have no climate significance. By the time the feedbacks get their collective acts together the changes in forcings have already moved on with THEIR direct effects on the system.
So anyone who thinks that feedbacks caused by human activity can affect the system significantly are wrong. That includes every climate model ever constructed and the entire climate establishment.
And all one needs to have such a profound effect on the system energy budget is to alter global cloudiness via a redistribution of the surface air pressure systems. That seems to be a natural cyclical consequence of an interplay between top down solar and bottom up oceanic variations.
Sadly, if it weren’t for the billions of dollars spent on climatology (regarding global warming etc.) and the trillions of tax dollars in play, this is a subject that not only would I care nothing about but I would pay it even less attention.
In fact, acknowledging that clouds act as a brake on a warming planet and that they serve to moderate insolation effects is of key importance. That the established climate crowd will refute this until the cows come home, goes without saying.
Great good luck, Dr. Spencer, for you diligent pursuit of the truth in the face of near-insurmountable odds and unjustified criticism. No matter what your personal beliefs, the truth will set us all free. 🙂
Roy Spencer writes:
“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.”
Warmista cannot break free from their “radiation only” models of climate. They treat clouds and all such natural phenomena as epiphenomena of radiation. In other words, clouds can only be affected by climate changes and cannot affect climate. They must learn to respect the natural phenomena and create physical hypotheses that describe them.
By the way, at some point we are going to get to real science and we will do away with charged metaphors such as “forcing” and “feedback” which are multiply ambiguous. In real science, such terms are replaced by universal generalizations that describe the flow of cause and effect among the objects under study.
Thanks again for your good work.
I completely agree with what Ian W (at 4:39 AM) says:
“What is also needed is a graph showing what the CERES data should look like if the IPCC/AGW feedback hypothesis was true. Having shown the hypothesis it can then be compared to reality and falsified.”
I don’t know if there would be a statistically significant falsification of the models in this case, but that is the wrong way to look at the issue. You don’t assume the models are right if reality doesn’t falsify at the 95% confidence level. You start with the assumption that reality is right, then you see how different the models are, in my view. What we need is the side by side comparison.
Thanks Dr. Spencer. You have made very clear to me that although clouds are a response to surface temperature, they are more of a cause of surface temperature. So much more, that if one was to oversimplify, it would be less of a mistake to consider clouds as just a forcing instead of as just a feedback.
As to what modulates clouds, ask Svensmark, I think he knows.
Dr Roy,
“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.”
Really? I wish you’d give a quote to back that up, because I don’t believe it is true. He’s just saying that you can’t identify a strong feedback. That doesn’t mean that ergo there is forcing – it may be something else. He spells that out in the 2010 paper:
“Obviously, the correlation between ΔR_cloud and ΔT_s is weak (r2 = 2%), meaning that factors other than T_s are important in regulating ΔR_cloud. An example is the Madden-Julian Oscillation (7), which has a strong impact on ΔR_cloud but no effect on ΔTs. This does not mean that ΔTs exerts no control on ΔR_cloud, but rather that the influence is hard to quantify because of the influence of other factors. As a result, it may require several more decades of data to significantly reduce the uncertainty in the inferred relationship.”
Semantics —————- often viewed as trivial, and are, that is, until it gets in the way of communication. Feedback vs forcing? Obviously there are other forces (heh) that change cloud cover other than an increase in temps. And, obviously, clouds effect our temps. I suppose it would be more correct to say energy transfer as opposed to temps. Wouldn’t that meet the explanation of a forcing? But, then, wouldn’t all factors meet that criteria, save for the external forcing, to whit, the sun?
Maybe our friends Tbear, Pete, et al are on to something. Perhaps a primer with simple explanations of terms would be of some use. Though, I’m not sure anything would actually suffice for all. The problem is that none of us entered the discussion at the same time, and, each of us has a different level of understanding when we entered. Then, we all have different perspectives, as well.
John Marshall says:@ur momisugly October 9, 2011 at 1:53 am “……..”, well nothing other than to slide a snide, yet, cryptic comment into the discussion.
Ask why is it so? October 9, 2011 at 5:25 am
“…however, until evidence to prove that the Second Law of Thermodynamics is wrong, Long Wave radiation, being energy lower (colder) than Short Wave (hotter) cannot travel from an area of lower energy, i.e. the cloud to an area of higher energy, i.e. the surface of the earth.”
Radiation travels in any direction it wants; from hot to cold and cold to hot. It does this all the time. I believe you meant to say that the simultaneous net of the radiation from the cold surface to the warm surface and from the warm to the cold is dominated by the latter because of radiations dependence on an objects absolute temperature raised to the 4th power. Yes?
@Roy A web page with definitions of terms would help. Your definitions, others definitions. That way you can just link to it if people want to know what you’re talking about in any particular discussion. It seems like the argument always gets cluttered up with an inadequate definition of terms.
I am lost without definitions.
Re: DocMartyn says:
October 9, 2011 at 6:09 am
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It is not really appropriate to get into this debate since it is O/T to the Spencer article.
I envisage that everyone accepts the statement that “…you know that matter radiates photons as a function of its temperature and emissivity. Cold objects radiate less energy than hot objects, if they have the same emissivity….”
The problem is with your further statement “Take two equally sized nearby objects with the emissivity, one at 100K and one at 400K, They will both emit photons and both absorb photons, the cold object will receive photons from the hot object and the hot one will receive photons from the cold one.” That statement may be correct but then again, it may not be. I have never seen an experiment proving the correctness of that assertion and I consider that it is mere supposition albeit it I can understand the reason why someone may conclude that it is correct. However, I consider that we know and understand and have insufficent understanding of photons to be certain that you are correct.
For example, lets consider that I have a room with an open door. I have a very powerful fan say 3 feet from the door aimed at the door. This very powerful fan blasts air at 400mph out through the door. Now outside that room say some 50 feet away from the open door I set up a similar but less powerful fan aimed at the door. This blasts air at 100mph ained towards the open door. What proportion if any of the air molecules blasted by the less powerful fan find their way through the door and into the room?
My point is this. Merely because a low temperature object radiates energy, it does not follow that that energy can pass the threshold and get absorbed by a warmer object which is radiating energy at a higher state. may be it can, but may be it does not and this can be clarified only by properly constructed experimentation which to my knowledge has not been undertaken such that we simply do not know the answer to what is a very important issue in the climate science field.