What we don’t know about Earth's energy flow

Roger Tattersall (aka Tallbloke) writes on his blog of a WUWT comment. Unfortunately WUWT gets so many comments a day that I can’t read them all (thank you moderators for the help). Since he elevated Dr. Robert Brown’s comment to a post it seems only fair that I do the same.

I saw this comment on WUWT and was so impressed by it that I’m making a separate post of it here. Dr Brown (who is a physicist at Duke University) quotes another commenter and then gives us all an erudite lesson. If Nikolov and Zeller feel they need to take any of the complaints on WUWT about the way  they handle heat distribution from day to night side Earth seriously, they probably need to study this post carefully. this is also highly relevant to the reasons why Hans Jelbring used a simplified model for his paper, please see the new PREFACE added to his post for further elucidation.

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I can’t speak for your program, but I will stand by mine for correctly computing the ‘mean effective radiative temperature’ of a massless gray body as a perfect radiator. Remember, there is no real temperature in such of an example for there is no mass. It takes mass to even define temperature. (but most climate scientist have no problem with it and therefore they are all wrong, sorry)

I’d like to chime in and support this statement, without necessarily endorsing the results of the computation (since I’d have to look at code and results directly to do that:-). Let’s just think about scaling for a moment. There are several equations involved here:

P = (4\pi R^2)\epsilon\sigma T^4

is the total power radiated from a sphere of radius R at uniform temperature T. \sigma is the Stefan-Boltzmann constant and can be ignored for the moment in a scaling discussion. \epsilon describes the emissivity of the body and is a constant of order unity (unity for a black body, less for a “grey” body, more generally still a function of wavelength and not a constant at all). Again, for scaling we will ignore \epsilon.

Now let’s assume that the temperature is not uniform. To make life simple, we will model a non-uniform temperature as a sphere with a uniform “hot side” at temperature T + dT and a “cold side” at uniform temperature T – dT. Half of the sphere will be hot, half cold. The spatial mean temperature, note well, is still T. Then:

P’ = (4\pi R^2)\epsilon\sigma ( 0.5*(T + dT)^4 + 0.5(T – dT)^4)

is the power radiated away now. We only care how this scales, so we: a) Do a binomial expansion of P’ to second order (the first order terms in dT cancel); and b) form the ratio P’/P to get:

P’/P = 1 + 6 (dT/T)^2

This lets us make one observation and perform an estimate. The observation is that P’ is strictly larger than P — a non-uniform distribution of temperature on the sphere radiates energy away strictly faster than it is radiated away by a uniform sphere of the same radius with the same mean temperature. This is perfectly understandable — the fourth power of the hot side goes up much faster than the fourth power of the cold side goes down, never even mind that the cold side temperature is bounded from below at T_c = 0.

The estimate: dT/T \approx 0.03 for the Earth. This isn’t too important — it is an order of magnitude estimate, with T \approx 300K and dT \approx 10K. (0.03^2 = 0.0009 \approx 0.001 so that 6(0.03)^2 \approx 0.006. Of course, if you use latitude instead of day/night side stratification for dT, it is much larger. Really, one should use both and integrate the real temperature distribution (snapshot) — or work even harder — but we’re just trying to get a feel for how things vary here, not produce a credible quantitative computation.

For the Earth to be in equilibrium, S/4 must equal P’ — as much heat as is incident must be radiated away. I’m not concerned with the model, only with the magnitude of the scaling ratio — 1375 * 0.006 = 8.25 W/m^2, divided by four suggests that the fact that the temperature of the earth is not uniform increases the rate at which heat is lost (overall) by roughly 2 W/m^2. This is not a negligible amount in this game. It is even less negligible when one considers the difference not between mean daytime and mean nighttime temperatures but between equatorial and polar latitudes! There dT is more like 0.2, and the effect is far more pronounced!

The point is that as temperatures increase, the rate at which the Earth loses heat goes strictly up, all things being equal. Hot bodies lose heat (to radiation) much faster than cold bodies due to Stefan-Boltzmann’s T^4 straight up; then anything that increases the inhomogeneity of the temperature distribution around the (increased) mean tends to increase it further still. Note well that the former scales like:

P’/P = 1 + 4 dT/T + …

straight up! (This assumes T’ = T + dT, with dT << T the warming.) At the high end of the IPCC doom scale, a temperature increase of 5.6C is 5.6/280 \approx 0.02. That increases the rate of Stefan-Boltzmann radiative power loss by a factor of 0.08 or nearly 10%. I would argue that this is absurd — there is basically no way in hell doubling CO_2 (to a concentration that is still < 0.1%) is going to alter the radiative energy balance of the Earth by 10%.

The beauty of considering P’/P in all of these discussions is that it loses all of the annoying (and often unknown!) factors such as \epsilon. All that they require is that \epsilon itself not vary in first order, faster than the relevant term in the scaling relation. They also give one a number of “sanity checks”. The sanity checks suggest that one simply cannot assume that the Earth is a ball at some uniform temperature without making important errors, They also suggest that changes of more than 1-2C around some geological-time mean temperature are nearly absurdly unlikely, given the fundamental T^4 in the Stefan-Boltzmann equation. Basically, given T = 288, every 1K increase in T corresponds to a 1.4% increase in total radiated power. If one wants a “smoking gun” to explain global temperature variation, it needs to be smoking at a level where net power is modulated at the same scale as the temperature in degrees Kelvin.

Are there candidates for this sort of a gun? Sure. Albedo, for one. 1% changes in (absolute) albedo can modulate temperature by roughly 1K. An even better one is modulation of temperature distribution. If we learn anything from the decadal oscillations, it is that altering the way temperature is distributed on the surface of the planet has a profound and sometimes immediate effect on the net heating or cooling. This is especially true at the top of the troposphere. Alteration of greenhouse gas concentrations — especially water — have the right order of magnitude. Oceanic trapping and release and redistribution of heat is important — Europe isn’t cold not just because of CO_2 but because the Gulf Stream transports equatorial heat to warm it up! Interrupt the “global conveyor belt” and watch Europe freeze (and then North Asia freeze, and then North America freeze, and then…).

But best of all is a complex, nonlinear mix of all of the above! Albedo, global circulation (convection), Oceanic transport of heat, atmospheric water content, all change the way temperature is distributed (and hence lost to radiation) and all contribute, I’m quite certain, in nontrivial ways to the average global temperature. When heat is concentrated in the tropics, T_h is higher (and T_c is lower) compared to T and the world cools faster. When heat is distributed (convected) to the poles, T_h is closer to T_c and the world cools overall more slowly, closer to a baseline blackbody. When daytime temperatures are much higher than nighttime tempratures, the world cools relatively quickly; when they are more the same it is closer to baseline black/grey body. When dayside albedo is high less power is absorbed in the first place, and net cooling occurs; when nightside albedo is high there is less night cooling, less temperature differential, and so on.

The point is that this is a complex problem, not a simple one. When anyone claims that it is simple, they are probably trying to sell you something. It isn’t a simple physics problem, and it is nearly certain that we don’t yet know how all of the physics is laid out. The really annoying thing about the entire climate debate is the presumption by everyone that the science is settled. It is not. It is not even close to being settled. We will still be learning important things about the climate a decade from now. Until all of the physics is known, and there are no more watt/m^2 scale surprises, we won’t be able to build an accurate model, and until we can build an accurate model on a geological time scale, we won’t be able to answer the one simple question that must be answered before we can even estimate AGW:

What is the temperature that it would be outside right now, if CO_2 were still at its pre-industrial level?

I don’t think we can begin to answer this question based on what we know right now. We can’t explain why the MWP happened (without CO_2 modulation). We can’t explain why the LIA happened (without CO_2 modulation). We can’t explain all of the other significant climate changes all the way back to the Holocene Optimum (much warmer than today) or the Younger Dryas (much colder than today) even in just the Holocene. We can’t explain why there are ice ages 90,000 years out of every 100,000, why it was much warmer 15 million years ago, why geological time hot and cold periods come along and last for millions to hundreds of millions of years. We don’t know when the Holocene will end, or why it will end when it ends, or how long it will take to go from warm to cold conditions. We are pretty sure the Sun has a lot to do with all of this but we don’t know how, or whether or not it involves more than just the Sun. We cannot predict solar state decades in advance, let alone centuries, and don’t do that well predicting it on a timescale of merely years in advance. We cannot predict when or how strong the decadal oscillations will occur. We don’t know when continental drift will alter e.g. oceanic or atmospheric circulation patterns “enough” for new modes to emerge (modes which could lead to abrupt and violent changes in climate all over the world).

Finally, we don’t know how to build a faithful global climate model, in part because we need answers to many of these questions before we can do so! Until we can, we’re just building nonlinear function fitters that do OK at interpolation, and are lousy at extrapolation.

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long pig

Excellent – a true reality check. A much-needed antidote to back-of-envelope AGW Arrhenius complacency. Yes it is a complex system and no it is not understood or in any way settled. Thank-you Dr Brown!

Amen to some common sense.

I agree with Roger 100%
I know of him from the early Beowulf days and we used his code for monitoring nodes.

P.F.

Is there any doubt that WUWT is the hands-down best science blog on the Internet? One simply does not see this kind of insight and reason on any of the AGW/climate change sites.

FijiDave

Excellent!

TerryS

In the text.
\pi = π
\approx = &approx;
\epsilon = ε
\sigma = σ

NavarreAggie

Wow. That was a very good piece. Thanks!

Bloke down the pub

Nice piece of work. I can’t pick fault with it, though of course that doesn’t say a lot.

Talking about complexity and issues that we do NOT know, the greatest uncertainty appears to be in the impact of clouds. There is an excellent lecture on clouds by:
Graeme L. Stephens, JPL Climate Change – A Very Cloudy Picture (or link via: A21G Charney Lecture, Moscone West Rooms 2022-2024, AGU FALL Meeting 2011
I found particularly interesting his observations that climate models strongly differ even on the sign of the feedback. e.g. See:
Cloud feedback versus total feedback

“Conclusion: Differences in cloud feedback are again the largest single source of uncertainty of all feedbacks (range from -0.5 W/m^2/K to + 0.7 W/m^2/K)” – Andrews et al. 2012 (at 18’20”-19’00”)

Stephens commented that cloud effects are so varied and complex and have so many variables (at least three major ones) that they will always remain the greatest uncertainty in modeling.
I also found it interesting how clouds very strongly change the climate response to water:

“The ‘thermal absorbent’ character of water is greatly enhanced when in condensed phase. On a molecule by molecule basis, water in either solid or liquid form in the atmosphere absorbs more than 1000 times more strongly – a relative small amount of liquid or solid water disproportionally influences the flow of radiant energy through the Earth system.” (24’55” – 26’12”)

Willis Eschenbach has been exploring the diurnal impact of clouds, from night to day, and their feedbacks etc.
From Greame Stephens comments, I would not at all be surprised if Willis’ findings on day/night cloud variations have a similar order of magnitude impact as the day/night calculations in the above post.

John West

Lot’s of letters and symbols. I guess it’s good from the comments. Guess i shoudln’t have skipped math afterall.
[Or grammmar and punctuation.☺ ~dbs]

R. Gates

This is an excellent post, and this quote in particular:
“Until all of the physics is known, and there are no more watt/m^2 scale surprises, we won’t be able to build an accurate model, and until we can build an accurate model on a geological time scale, we won’t be able to answer the one simple question that must be answered before we can even estimate AGW:
What is the temperature that it would be outside right now, if CO_2 were still at its pre-industrial level?”
_____
Is quite outstanding, and right on target, but misses the point of climate models. Of course, we’ll never be able to tell you exactly what the temperature would be outside “right now” from a model of the climate. Everyone in the business, from Trenberth on down will tell you that models will never be right, are never “right”, and will never tell every little detail, especially daily temperatures for you’re dealing with two vastly different scales. But this isn’t the point of models, nor the reason for constructing them or studying them. Models don’t have to be 100% accurate to be useful. The power of a model is if it is useful enough to tell us things that we couldn’t have known without them. Models are essentially maps– albeit dynamic maps. Maps won’t tell you every little detail of the actual territory, every little side street or crack in the side walk, but they can be useful enough, giving you enough of the major features of a territory to allow you to know something useful about that territory.
Could a climate model ever tell you exactly how much colder (or warmer) it might be outside right now if CO2, N20, CH4, and water vapor were at such and such a level? Never. Could a model tell you the probability that it would be colder (or warmer) outside on a given day when comparing two different sets of greenhouse gas concentrations and holding all other variables constant? Absolutely…and that is precisely what they are meant to do.

The processes of evaporation/condensation and freezing/thawing are the factors that are controlling the rate of energy loss to space. Radiative energy transfer is essentialy “fast as light and line of sight”. The rates of these controlling processes are much slower. For example, In the arctic in winter,conductivity thru the sea ice is the rate controller. The “greenhouse effect” is insignificant by comparison. At the South Pole in winter, it is the rate of energy being delivered through the atmosphere and snow rate that are controlling. Of course, clouds are a barrier blocking the line of sight. Also, they transport energy.

Russell Seitz

And in conclusion, when physicists find they have gotten nowhere by writing down Boltzmanns equation while setting thermal mass to a non-physical value , they put down the chalk, and begin to think about breaking the problem down into its component parts , which may be iteratively arranged to produce a computational scheme capable of incorporating the mass elements of the system, and the optical depth integrals of the components of the atmosphere
This is known as a model.
Absent one , the algebra cannot save you from talking nonsense,* or generating something you wouldn’t dare scribble as a comment in a physics blog.
[snip. Try to have a little more class. ~dbs, mod.]
* paraphrase in memoriam John McCarthy

kalsel3294

An excellent post. The alarmists who confine themselves to the simple physics are lacking in the ability to comprehend the far more complex logistics. Places like SkS can’t see the forest for the trees, cherrypicking the logistics to support the very basic physics rather than using the physics to support the mind blowing logistics.
The pro AGW crowd may well make faithful postmen, able to deliver a single previously sorted letter from their local post office to the correct street address, but it takes the sceptics to appreciate the logistics involved that enables all deliveries to happen on a global scale under all conditions.

J. Snow

R. Gates says:
“Could a climate model ever tell you exactly how much colder (or warmer) it might be outside right now if CO2, N20, CH4, and water vapor were at such and such a level? Never. Could a model tell you the probability that it would be colder (or warmer) outside on a given day when comparing two different sets of greenhouse gas concentrations and holding all other variables constant? Absolutely…and that is precisely what they are meant to do.”
OK… but… if the model is not calibrated with reality then what’s the point. If you create a model that relates GHG concentration to temperature and the correlation is always positive then the model will show that increasing CO2 concentration increases temperature, i.e. AGW. Models that don’t or can’t account for all the physical variables are worthless unless you are trying to force a specific answer.
The physical universe is the ultimate guru.

Tom G(ologist)

A.W. What do you mean we don’t know when the Holocene WILL end. It WILL end a couple hunderd years AGO (see http://suspectterrane.blogspot.com/)
And we thereby see that pure science types must continue to propose preposterous ideas to keep the gravy train rolling.

Frank K.

R. Gates says:
January 6, 2012 at 9:28 am
“Could a model tell you the probability that it would be colder (or warmer) outside on a given day when comparing two different sets of greenhouse gas concentrations and holding all other variables constant? Absolutely and that is precisely what they are meant to do.”
Yes, but will that predicted probability be correct? What if, instead of a predicted 50% chance of increased average temperatures over a given period of time given a certain initial condition, the real answer is 5%? Or 0.5%?
My personal opinion is that the climate models are not mature enough to provide any reliable predictions. While it’s of academic interest to do what-if scenarios with models, I would NOT base any important economic decisions on their output…
(Of course, we could also discuss how the climate models are constructed, the numerical methods, boundary/initial conditions, source terms and feedbacks, well-posedness etc. but no one ever wants to get into that, and it would distract from the current thread).

Elftone

R. Gates says:
January 6, 2012 at 9:28 am
Could a climate model ever tell you exactly how much colder (or warmer) it might be outside right now if CO2, N20, CH4, and water vapor were at such and such a level? Never. Could a model tell you the probability that it would be colder (or warmer) outside on a given day when comparing two different sets of greenhouse gas concentrations and holding all other variables constant? Absolutely…and that is precisely what they are meant to do.

Quite so – but as we don’t seem to even know what all the significant variables are, how they interact or what impact each actually has, models approach the usefulness of the Drake Equation. They appear to be too-simplistic approximations of complex systems… more like thought-experiments, with a bunch of so-far baseless (sorry) assumptions made to fill in the blanks.

D Snyder

Is it fair to sum this up as: The average temperature is a useless parameter? or only mostly useless?

Disko Troop

R. Gates:
“and holding all other variables constant”.
Variables? Constant?
Exactly……..Garbage in.

Willis Eschenbach

R. Gates says:
January 6, 2012 at 9:28 am

This is an excellent post, and this quote in particular:

“Until all of the physics is known, and there are no more watt/m^2 scale surprises, we won’t be able to build an accurate model, and until we can build an accurate model on a geological time scale, we won’t be able to answer the one simple question that must be answered before we can even estimate AGW:
What is the temperature that it would be outside right now, if CO_2 were still at its pre-industrial level?”

_____
Is quite outstanding, and right on target, but misses the point of climate models. Of course, we’ll never be able to tell you exactly what the temperature would be outside “right now” from a model of the climate. Everyone in the business, from Trenberth on down will tell you that models will never be right, are never “right”, and will never tell every little detail, especially daily temperatures for you’re dealing with two vastly different scales. But this isn’t the point of models, nor the reason for constructing them or studying them. Models don’t have to be 100% accurate to be useful. The power of a model is if it is useful enough to tell us things that we couldn’t have known without them. …

Thanks, R. Couldn’t agree more, and someday climate models may actually reach the point you mention, where they can tell us things we wouldn’t have known without them.
Don’t hold your breath while waiting for the climate models to come up with their first useful result, however …
w.

stevenlibby

Whenever I hear “it’s basic physics” mentioned by the CAGW crowd I growl to myself, “which of the dozens if not hundreds of ‘basic physics’ processes affecting climate are you referring to and how sure are you about their interactions, scales, sign or even if we know we’ve found them all yet?” The devil is rarely in any one ‘basic physics’ process but in how all of them work together in this amazing planet we live on to keep us alive and thriving!
Great article.
BTW – WUWT has single-handed changed my mind on the benefits of blogs. I would consider it to be one of very few blogs that has actually achieved what blogs were intended to do and it’s a delight to observe. Thanks to all who make this possible!

Viv Evans

Reality checks about what we do and mostly do not know are always welcome.
Doing research in an ‘unsettled ‘ science subject is far more interesting to keen, young minds than having to follow a ‘settled’ science track where only tiny details are allowed to be looked at and where dissent is discouraged.

jim hogg

At last: honesty, high intelligence and appropriate knowledge that admits how little we know, and how much more we need to know if we’re to make sense of climate variation. Thank you Mr Watts for making space for this.

D. J. Hawkins

R. Gates says:
January 6, 2012 at 9:28 am
… Could a climate model ever tell you exactly how much colder (or warmer) it might be outside right now if CO2, N20, CH4, and water vapor were at such and such a level? Never. Could a model tell you the probability that it would be colder (or warmer) outside on a given day when comparing two different sets of greenhouse gas concentrations and holding all other variables constant? Absolutely…and that is precisely what they are meant to do.

And that is precisely what they CAN NOT do. And why they also shouldn’t be used as the basis for policy dealing with the supposed effects of CAGW, most especially since the proposals involve significant disruption to national economies.
Look at it this way. If I hold a 5 pound weight 4 feet above my foot and let go, common experience, Newton’s laws of motion, and the laws of gravity all support the prediction that my foot will be very unhappy in +/- 0.5 seconds unless I move it out of the way. We’re not there yet with climate science. Until we are, we should husband our resources to deal with any putative “climate catastrophies” as they occur rather than waste them on measures that we have no idea if they will mitigate such alleged forthcoming catastrophies.

Gary Pearse

I believe Dr. Robert Brown’s outstanding and very readable commentary on how energy flows brings climate science literally out of its Dark Ages. Oh its nothing particularly new in the world (but quite new to mainstream climate science, it would appear). Everyone knows that a school boy can calculate marvelous things by memorizing formulae and without the necessity of understanding the least thing about the meaning of it all. Climate scientists, I fear, have demonstrated the ‘school boy’ mentality everytime we have been treated to a lecture on the LWIR radiative transfer of heat. Otherwise they wouldn’t make the mistake of thinking an average temperature can be used in their “Energy Budgets and Imbalances”. They would have realized that the bigger the variability of temp, the bigger the radiative heat loss purely using the Stefan-Boltzmann law simply because of the exponential power of 4.
Tallbloke, may I recommend you add to the post the very poetic follow-up comments made by Dr. Brown in the “Feedback about feedbacks and suchlike fooleries” December 30, 2011 By Christopher Monckton of Brenchley: describing the brewing of beer worts and convection in the mash and the atmosphere at:
Robert Brown says:
January 2, 2012 at 10:05 am
It, too, is a beautiful treatise on how things work in the atmosphere and the determination of energy to do work and dump that heat into the 3K temp regime of space. Dr. Brown I would love to sit in on your lectures at Duke, maybe spiced up with a fine bitter homebrew.

A Little Voice

Ahhh….the age old problem of linearizing everything (sometimes it is a poor approximation and gets you in trouble) and assuming those terms are “neglible” (ditto). I learned this as an undergraduate engineer and as a practicing engineer. But even if the models are “robust” you need data to initialize them (yet another problem).
The mark of a good scientist/engineer is knowing when NOT to apply linearization or simplifying assumptions.
I would like to point out the handful of comments Dr. Brown made that I think are particularly insightful other than the lecture on the Stefan-Boltzmann Law::
1) “a function of wavelength and not a constant at all” – gave me chills reading that
2) “one should use both and integrate the real temperature distribution (snapshot) — or work even harder.”
My thoughts exactly, I would be very interested in seeing what this result looks like. The latitude 6*dT/T^2 is almost two orders of magnitude larger!
3) “When heat is concentrated in the tropics, T_h is higher (and T_c is lower) compared to T and the world cools faster.”
This highlights the role Antarctica plays in the geologically recent ice ages. Having a continent at the South Pole results in two strong forcing events 1) high albedo over a large area and 2) impenetrable weather system that results in little mixing (high dT).
4) “We don’t know when continental drift will alter e.g. oceanic or atmospheric circulation patterns “enough” for new modes to emerge ”
When Antarctica drifts away from the South Pole, the effects on climate, ocean levels, etc. will be so dramatic that this worrying over AGW will seem pointless. However, we can rest comfortably more many years to come (depending on your perspective I guess). Because I think one takeaway from Dr. Brown’s comment is that the Earth’s weather is somewhat extreme right now as a result of Antarctica. Lots of very hot and very cold places with little mixing that is resulting in high rates of cooling. These high rates of cooling make the Earth’s climate more sensitive to changes in the Sun’s radiation and perhaps more sensitive to changes in the Earth’s atmosphere as well (I am just speculating here)? But I am certain when Antarctica moves off the South Pole the climate will be less extreme and more mild (that’s saying nothing about whether it is colder or warmer).
Dr. Brown asks the interesting question: What is the temperature that it would be outside right now, if CO_2 were still at its pre-industrial level?
Is it reasonable to assume it would be colder? How about the question regarding “extreme weather”? I suppose one could argue that by raising the temperature somewhat, say 1K, could result in increased extreme weather events because of the faster cooling that Dr. Brown outlines. But, to me this is a co-opting of a description of the Earth’s current weather that has nothing to do with human activity.

Septic Matthew

R. Gates: Is quite outstanding, and right on target, but misses the point of climate models. Of course, we’ll never be able to tell you exactly what the temperature would be outside “right now” from a model of the climate.
There is more than one point to climate models. They do systematically assemble knowledge, and the comparison of model output to measured values provides tests of the accuracy of the knowledge, and its completeness. Model outputs are also used to inform policy decisions. That we can not know what the spatio-temporally averaged temperature would be today implies that we can not use the knowledge encompassed by the model to make inferences about future CO2 change or to make policy recommendations.
Models don’t have to be 100% accurate to be useful.
To be useful, the models have to have a record of being accurate enough to be useful. No such record exists. Since you mention Trenberth, there are two “travesties” concerning the “missing heat”: (1) first that it can not be explained and (2) major policy advocates in the field of climate science act as though the the lack of explanation does not matter for policy purposes. It clearly shows that a policy of reducing CO2 might be futile, which would be self-defeating.

“Alteration of greenhouse gas concentrations — especially water”
CO is not a greenhouse gas; it’s an energy converter that converts heat to IR in both directions. At night CO2 and water vapor are serious energy leaks, converting heat energy to IR. During the day, it’s a relative wash.
It is O2 and N2 that cannot cool themselves by emitting IR. That would make them greenhouse gases (heat-trapping) and CO2 and water vapor would be the same as drilling lots of small holes in the roof of a real glass greenhouse. The holes decrease the greenhouses effectiveness, serving to cool it.
“We can’t explain why the MWP happened (without CO_2 modulation). We can’t explain why the LIA happened (without CO_2 modulation).”
Sure we can, if we admit that the Sun is a big player here. It was not the LIttle Ice Age that caused the Maunder Minimum. There is very cogent evidence of a correlation between solar activity and climate. The recent elegant work showing the role of the comic vs solar wind in cloud formation can easily explain the Medieval Warm Period and Little ice Age. Let’s not pretend to know less than we know even though we do indeed no know everything yet.
By the way, sediment studies clearly show that the Gulf Stream actually ramps up during warm times and slows during cool. This contradicts nicely the warmest claims that warming would stop the Gulf Stream conveyor belt. Think about it: warmer water is less viscous and flows more easily; colder water would be more viscous and thus be sluggish. ‘Works for me.

Steve Keohane

R. Gates says:January 6, 2012 at 9:28 am
[…]
Models are essentially maps– albeit dynamic maps. Maps won’t tell you every little detail of the actual territory, every little side street or crack in the side walk, but they can be useful enough, giving you enough of the major features of a territory to allow you to know something useful about that territory.
Could a climate model ever tell you exactly how much colder (or warmer) it might be outside right now if CO2, N20, CH4, and water vapor were at such and such a level? Never. Could a model tell you the probability that it would be colder (or warmer) outside on a given day when comparing two different sets of greenhouse gas concentrations and holding all other variables constant? Absolutely…and that is precisely what they are meant to do.

An interesting unsubstantiated position, care to rectify with David L. Hagen says:
January 6, 2012 at 9:23 am
in regards to Stephen’s paper’s conclusion:
“Conclusion: Differences in cloud feedback are again
the largest single source of uncertainty of all feedbacks
– Andrews et al. 2012 (at 18’20”-19’00”)

For that reason and what all else we do not know, I have to agree with Willis @ 10:20am Don’t hold your breath while waiting for the climate models to come up with their first useful result, however …

Bill Illis

The day versus night argument (made by some) is based on a misjudgement of what the actual data says.
During the daytime, the peak in-radiation from the Sun is about 960.0000 joules/second, yet the surface temperature only increases by a miniscule 0.0007 joules/second. At night, now there is no 960 joules coming in per second (virtually none) and the temperature is only declining by 0.0007 joules/second.
That is for the surface. For the tropopause and in water, the changes are only +/- 0.00005 joules/second in daytime and at night. The OHC numbers from Schuckmann that we reviewed last week translate into an absorption rate by the oceans of just 0.00000002 joules/second.
As I’ve said, we need to incorporate time into the equations. A Watt/m2 is actually a Joule/second/m2.

Justin K

@stevenlibby says:
Whenever I hear “it’s basic physics” mentioned by the CAGW crowd I growl to myself, “which of the dozens if not hundreds of ‘basic physics’ processes affecting climate are you referring to and how sure are you about their interactions, scales, sign or even if we know we’ve found them all yet?” The devil is rarely in any one ‘basic physics’ process but in how all of them work together in this amazing planet we live on to keep us alive and thriving!
Great article.
BTW – WUWT has single-handed changed my mind on the benefits of blogs. I would consider it to be one of very few blogs that has actually achieved what blogs were intended to do and it’s a delight to observe. Thanks to all who make this possible!
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That is exactly the point I was making to R. Gates in another thread about the application of physics on small vs. large scale objects. We use different physics for each one as they work in conjunction with each other, but we still do not know all the pieces and it will be a long, long time, if ever, before we do. Someone arguing for simple physics hasn’t taken a physics class.
I second your last comment. It truly is an amazing blog. And I, for one, look forward to the contributions of those like R. Gates and “a physicist”, as infuriating as they may be to others, because they keep the debate going and present sides that I think only makes all of us better observers and thinkers.

First year University physics was a long time ago, but this is a wonderfully clear explanation. Thanks Dr Brown for writing, Roger for highlighting and Anthony for re-posting.

Kev-in-UK

I think R Gates is still expecting too much out of a ‘model’ – in the purest sense, a model is a good representation of the real ‘thing’ (whatever it may be) – the accuracy of the model is not only in its overall reflection of the ‘real thing’ but the behaviour of the ‘real thing’ – in climate models this is simply not even remotely possible due to the complexity of the system. The map analogy is quite good (especially if you consider ‘knowledge’ and scientific understanding as the ‘scale’) – but if you stop and think about what ‘scale’ of map(knowledge) we have regarding climate – we are probably around the small globe with continents scale! (i.e. picture a childs bedside globe light!) – in other words the detail simply isn’t known. Now, think about the same small scale globe with some cyclones or other imaginery climate or weather on it – and realise that if your measurement from the model is a millionth of an inch ‘out’ – this would translate to hundreds of miles in ‘real’ life! Now, think about how you would ‘predict’ the track of that ‘weather’ from your climate model ‘accurately’, even with the best supercomputers.
My point is that the ‘model’ can never be truly representative and the simpler a model is (say based on 10 or 20 ‘variables) the less useful it actually is if the ‘real thing’ is much more complex. I think the term ‘useful’ is a little dubious when considering a non linear semi chaotic system which is our climate system – and then if you try and use it to make predictions, you are simply more hopeful than scientific! I suppose the ultimate extraction of urine comes from the AGW so-called ‘predictions ‘based on such models and the policy decisions made thereon??

TedK

Bravo! Bravo! (Standing applause)
Encore! Encore! (holding my fossil fuel burning CO₂ emitting lighter on high)
In spite of the RG’s attempts at sidestep with his climate prediction isn’t weather prediction delusion; this article does an excellent job of laying out basic physics hurdles for science to address before anyone can state “We know what is happening to earth’s energy balances”.

Dave D

Wow, I read it twice then thrice and it’s possible even a limited, middle aged chemical engineer, not mathematically blessed, can follow along! This guy has a gift for communicating complex issues.

Paul Murphy

umm?
This article seems to offer a nice semi-numerate argument supporting the unstated but obvious conclusion that the concept of a global average temperature cannot be realized (i.e. have its value measured) with the information we have.
More interestingly it strikes at the heart of what is missing from the Nikolov and Zeller paper: speculation on causation – specifically on what drives the differences they see as driving weather. Essentially they say change in A is related to change in B, and here’s how; but don’t say what causes change in B (local pressures)
A highly speculative possible answer can be derived from the loose couplings between atmosphere and earth, and between atmosphere and solar wind – and that idea nicely reduces the measurement problem this article is about oo.

It seems that the only part of the science that’s settled is that the climate models are right in the opinion of the modellers. The more that the models are shown to deviate from reality, the less likely they are to be right, hence the modellers’ strong desire to keep any reality away from the media and their government paymasters (and themselves of course).
That’s another reason why WUWT and similar sites are so vital. They shine the light of reality into the murky depths of the modellers’ models and minds, and display what they find to public view.

Great to see this one getting the WUWT megaphone as well, and apologies to Anthony for snaffling it. It was just so relevant to the debate we were having at the time on the talkshop I just posted it after asking Dr Brown for permission. I’ll alert Anthony to comments of this quality I come across while doing moderation work for WUWT in the future.
Two specific criticisms arose on Tamino’s blog in regard to this post. I’d be interested to see what the response is from people here on WUWT:
Patrice
“I’ve read this “article” and there is many, many things wrong. The first and the very basic is that Brown is using same albedo (or emissivity) for both IR and visible spectrum and thus, he is getting base Earth temp wrong (288 K, correct result is 255 K). From there on, any calculation and conclusion is meaningless, since the very basic assumption is wrong.”
Kevin McKinney
“One example would be the bit where he claims a 10% change in the “the rate of Stefan-Boltzmann radiative power loss,” then miscalls that the “radiative balance,” then says that this can’t possibly (“no way in hell”) result from a doubling of CO2 concentration, especially since it’s a “concentration of less than .1%.”
He’s confusing different parts of the process, neglecting others altogether–to wit, all feedbacks except the primary S-B feedback–and making a really naive physical/logical error besides–the concentration of GHGs isn’t of primary importance; the partial pressure is.”

cui bono

Superb! Plaudits to Dr Brown, Tallbloke & Anthony. On several recent threads at Dr Currys blog some of us have argued that what Dr Brown calls the “complex, nonlinear mix” of climate factors makes the reductionist GHG argument look very dodgy. I wish I’d read Dr Browns comments at the time. One day the current climate ‘paradigm’ (ugh!) is going to look so damn silly.

HankHenry

Interesting post. I always wondered about the proposition that the hotter something is the faster it cools because it seems like an object doesn’t cool in straight line fashion but rather along some kind of exponential curve. If I am interpreting things correctly this means that more slowly rotating objects will be cooler on average because it will have time to achieve higher temps and higher temperatures mean greater cooling. On the other hand this doesn’t seem quite correct because one could conversely say that a more slowly rotating object can achieve cooler temperatures on the dark side and hence there should be slower cooling. My intuition based on the commonplace experience of blowing on hot soup wants to believe that a faster rotating body would be cooler.
BTW, on the subject of earth’s albedo, it has been observed to be variable by monitoring earth shine hitting the moon. http://www.sciencedaily.com/releases/2004/05/040527233052.htm

Josh Halpern ( Eli rabbett) is quite helpful here in untangling a misconception:
“The statement that “The point is that as temperatures increase, the rate at which the Earth loses heat goes strictly up, all things being equal.” is where the good Doctor Brown goes GIGO. It is correct that the rate at which the Earth’s SURFACE loses heat goes strictly up, but the surface is NOT where most of the thermal IR is emitted to space.
That is rather high up in the atmosphere, which can be seen by comparing the emission to space with the Planck distribution of thermal emission from the surface (here for example, but there are plenty of accurate measurements and models). The point at which the emission curve matches a blackbody curve tells you what the temperature of the effective altitude at which emission is occurring to space. Raising the greenhouse gas concentration raises the level at which the emission to space occurs to a colder level, and thus one where emission is slower. To make up for that the surface has to warm in order to push more energy through the open window directly into space”
I dont know why people dont get this. GHGs increase the opacity of the atmosphere to IR.
The earth system loses energy back to SPACE one and only one way: via radiation. There is no conduction back to space, and no convection back to space. When you add more GHGs you increase the effective radiating height of the earth system. Raising that height results in a system that radiates from a colder place. That means the radiation loss will be slower as Brown argues.
Its the SLOWING of the rate of radiation loss at the TOA that drives the surface temperature UP.
Its not that back radiation warms the surface. Its a direct consequence of what Brown notes.
GHGs create a system that radiates from a higher colder place. Hence, it loses heat at a slower rate. hence the surface must “warm” or cool more slowly.
Rather than disprove AWG, brown has provided you all with the basic physics to understand it.
Finally, pushing heat “past” the GHG blanket at the surface, doesnt really get the job done.
why? because its the C02 in the stratosphere ( which is dry) that really matters.

Fernando (in Brazil)

Maybe one day.
I will be a personal friend of Tallbloke
after several beers.
I can say:
Our math is bad.
On the other hand.
The physics is essentially correct. (Under discussion)
It is evident that the mass of a body changes the radiation emitted by this.
Two bodies the same surface temperature emit different wavelengths if their masses are different (but this is not the case).
About N / Z:
A question? The Venusian atmosphere complete one rotation in 96 hours ?????

Love this article, which is a game-winning homer that I have saved to my hard drive.

Steven Mosher says:
January 6, 2012 at 11:46 am
Finally, pushing heat “past” the GHG blanket at the surface, doesnt really get the job done.
why? because its the C02 in the stratosphere ( which is dry) that really matters.

Good to see the warmateers in full retreat to points beyond the tropopause. 😉
Hey! You! Get off of my cloud!
Lol.

R. Gates

← Even with a busy tornado year, still no upward trend in tornadoesAmanda Carey: Green Movement Dead In The Water →
What we don’t know about Earth’s energy flow
Posted on January 6, 2012 by Anthony Watts
“Roger Tattersall (aka Tallbloke) writes on his blog of a WUWT comment. Unfortunately WUWT gets so many comments a day that I can’t read them all (thank you moderators for the help). Since he elevated Dr. Robert Brown’s comment to a post it seems only fair that I do the same.
“I saw this comment on WUWT and was so impressed by it that I’m making a separate post of it here. Dr Brown (who is a physicist at Duke University) quotes another commenter and then gives us all an erudite lesson. If Nikolov and Zeller feel they need to take any of the complaints on WUWT about the way they handle heat distribution from day to night side Earth seriously, they probably need to study this post carefully. this is also highly relevant to the reasons why Hans Jelbring used a simplified model for his paper, please see the new PREFACE added to his post for further elucidation.”
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I would like everyone to conduct a little thought experiment that illustrates several key points in climate, weather, chaos, and the difference between large forces and small forces, and how sometimes we only need to know the big picture to have a useful model of a system, without knowing details.
Imagine that you have a piece of glass that is as close to horizontal as possible, virtually parallel to the ground, like a table top would be. On this glass, in the center, you place a large drop of water. Assuming this glass was reasonably horizontal, the drop of water would stay right where you put it, as the intermolecular forces between the water molecules and the glass (mainly Si02) would be greater than the the pull of gravity in any one direction from the drop of water. Now imagine that you had a "model" that told you that as you tip the glass off of horizontal toward one direction, the water drop would begin to run toward that direction with the speed of the movement to be proportional to the degree of tilt off of horizontal. The speed and path of that drop across the glass would also be influenced by very minor changes in intermolecular bonding between the water and glass, and the path across the glass would be chaotic, but still deterministic in that very specific forces are controlling that path, but they are not measureable by any method we currently have. But your model is actually not concerned with the "natural variations" in the path of the water drop across the sheet of glass, but rather the relatively simple predition of the direction and relative speed of the drop as you tip ths glass more and more off the horizontal. Ultimately, your model predicts the drop of water will fall off the edge of the glass to the ground.
This simple thought experiment shows that we don't need to know the details of a process to understand a great deal about it and to make useful predictions. All current global climate models tell us that the additonal greenhouse gases humans have added since 1750 tip the glass off of horizontal and are causing movement in global temperatures. They vary in how much the glass has been tipped (sensitivity) and of course the exact path the water drop will take (natural variation) but they all say the glass is tilted and the drop of water should be moving.

Kelvin Vaughan

Can anyone help me? I have a problem with my heating radiators. They are not radiating. All the heat is being convected away from them towards the ceiling. The floor 6″ below the radiators is cold.
What can the problem be?

stevenlibby said @ January 6, 2012 at 10:20 am
“Whenever I hear “it’s basic physics” mentioned by the CAGW crowd I growl to myself, “which of the dozens if not hundreds of ‘basic physics’ processes affecting climate are you referring to and how sure are you about their interactions, scales, sign or even if we know we’ve found them all yet?” The devil is rarely in any one ‘basic physics’ process but in how all of them work together in this amazing planet we live on to keep us alive and thriving!
Great article.
BTW – WUWT has single-handed changed my mind on the benefits of blogs. I would consider it to be one of very few blogs that has actually achieved what blogs were intended to do and it’s a delight to observe. Thanks to all who make this possible!”
Yes, a most informative article. Now I know why I was so uncomfortable with Oke’s Boundary Layer Climates. Not that Oke is “High School physics” as CAGWers claim.
Not sure what “blogs were intended to do”. Jerry Pournelle was arguably the first with his Daynotes on BIX, the Byte information exchange. “[It] preceded the Web by a lot, and I also had a daily journal on GE Genie. Both of those would have been considered blogs if there had been any such term. All that was long before the World Wide Web.” The early Daynotes Gang members (http://daynotes.com/index20041001.html) mainly were communicating how we solved computer problems and sharing that info with the world. Naturally, we also wrote about our other interests as well. And argued with each other and our readers.
Certainly Anthony Watts deserves a medal for what he has achieved and I deem it a great privilege to have met him; especially since he went out of his way to visit Tasmania, a place that is so often left off the map.

R. Gates,
Since you ignore negative feedback, your ‘simple thought experiment’ is nonsense.