I’ve been having an interesting discussion with The Hockey Schtick and with Ronan Connolly on the new Gobal Warming Solved site (Archived here). What’s remarkable is the level of agreement. We agree that the atmosphere absorbs and emits radiation (mainly infrared). We agree that one can define an effective emission height in the atmosphere at which the temperature matches the equilibrium non-greenhouse temperature (yes, I realise that the actual emission is more complicated than this – see Eli Rabett’s post, for example). We agree that one can approximate the temperature gradient in the lower atmosphere (troposphere) using the adiabatic lapse rate (yes, I realise that the environmental lapse rate can differ from this – see Science of Doom’s post, for example). One can then estimate the surface temperature by working from the effective emission height (at which the temperature is known) down along the lapse to the surface (i.e., Tsurf = Teq + h dT/dz – using the absolute value of the gradient.)
Where we differ is what we call this process. I call it the greenhouse effect. I believe most others call it the greenhouse effect. The greenhouse gases set the effective emission height in the atmosphere, the lapse rate then sets the surface temperature. Ronan Connolly and The Hockey Schtick appear to call this something else and, consequently, conclude that the greenhouse effect is small, or negligible. An additional consequence of this is that they then conclude that since the greenhouse effect is negligible, adding more greenhouse gases to the atmosphere won’t warm the surface. This is where we differ greatly. Since I maintain that the greenhouse gases are setting the effective emission height in the atmosphere and that adding more will raise this height (which seems obvious, given that having none should mean that it’s on the surface of the planet), adding greenhouse gases should warm the surface.
What seems remarkable is that both The Hockey Schtick and Ronan Connolly seem to be a terminology away from being convinced of the greenhouse effect. They just don’t realise this yet. If they could recognise that the process they describe is actually the greenhouse effect, and if they could recognise the consequences of this realisation, it could be quite an epiphany. Wouldn’t it be great to undergo such an epiphany? The realisation that you now understand something better than you thought you had. Of course, I can’t really bring myself to continue my discussion with them as I’m no longer really sure what we disagree about. We disagree about the name, but it seems that overall we agree about the actual process. So, how does one have a discussion about the existence, or not, of the greenhouse effect when both sides are describing the same process?
...and Then There's Physics 
If doubling CO2 resulted in 0.0°C equilibrium surface warming, that would conflict with basic physics and 420 million years of paleoclimate evidence.
@DumbSci,
Indeed, that’s why I find it remarkable that people who seem to understand the processes quite well, are unable/unwilling to accept these basic facts.
ATTP
And then there’s paleoclimate.
This is what is so piquantly frustrating about these endless arguments about atmospheric physics. Step back one good pace and it is obvious that the GHE exists and GHGs are efficacious climate forcings. Otherwise paleoclimate behaviour tends towards the inexplicable.
Anybody who claims to be a GHE “sceptic” must deal with the mysteries arising or admit that they are arguing for something that flatly contradicts everything known about Earth’s climate behaviour in the past.
DS – sorry but we crossed. I spent too long editing my comment 😉
BBD,
Indeed and there are much easier ways (as you indicate) to show that the greenhouse effect exists than discussing atmospheric physics. For example, the surface is hotter than we expect, should really be good enough.
In the post, I was really just trying to highlight the irony of understanding the processes quite well, and yet still being unable to accept the existence of the greenhouse effect and the consequences of the existence of the greenhouse effect.
BBD,
Something I should probably do more of 🙂
ATTP:
And, when they realise, they will quickly backtrack and thank you for alerting them to just how close to the precipice they inadvertently got. 🙂
Witness the awesome power of denial 😉
See also Jason B, above…
The problem is the phrase ‘The Greenhouse Effect’ and all it stands for. And I’m sure they feel exactly the same about ‘The Hockey Stick’. They have so much invested in their denial that they have created a massive mental block. An amazing thing, the human mind. If you haven’t seen it watch this week’s ‘Horizon’: http://www.bbc.co.uk/programmes/b03wyr3c
Could you explain a little more? How can they *just* be arguing over the semantic use of `greenhouse effect’? Are you saying they actually accept the effect but won’t call it the same name? Or are they disagreeing that the components they’ve assembled all add up the same thing everyone else thinks they add up to? I mean, if they want to call it the “big bowl of spacefruit effect” but they’re talking about the same thing, that’s confusing for everyone but at least still accurate! I’m guessing that’s not what they’re doing…
Anders, if they don’t call the greenhouse effect, “the greenhouse effect”:
1) What do they call the greenhouse effect?
2) What do they describe when they describe what they call “the greenhouse effect”?
Dan,
I think my description is roughly what they think. They recognise that the atmosphere must absorb and emit radiation. They recognise that there must be a level in the atmosphere that matches the equilibrium non-greenhouse temperature. They recognise that the temperature gradient can be estimated from the adiabatic lapse rate. So, yes, they could simply call it something else and everything would still be accurate.
What seems to be the issue is that they’re unwilling to recognise that the effective emission height in the atmosphere is set by the GHGs. So, in a sense, it’s the next step where the disagreement comes in. The idea seems to be that they recognise that the GHGs play a role in absorption and emission, but not in setting the effective height in the atmosphere where the emission to space occurs. In fact, HS keeps arguing that increasing GHG concentrations will cool the surface because the negative lapse rate feedback from water vapour will change the lapse rate and hence decrease the surface temperature. What HS is essentially doing, however, is assuming that the emission height remains constant, which is incorrect. Increasing the GHG concentration moves the effective emission height up and that will typically compensate for any negative lapse rate feedback (I think).
Tom,
They don’t seem to call it anything, although the Connolly & Connolly papers are promoting a new process called pervection, that I still don’t quite understand.
This is where it’s interesting, because as far as I can tell, they’re essentially describing the greenhouse effect, and then concluding it doesn’t exist.
Hockey Schtick asked:
I think it is much more than not wanting to use the bad word greenhouse effect. Let’s look at the beginning of the discussion. Hockey Schtick claims that it would be much warmer without greenhouse gases. He fixes the effective emission height magically at 5 km and without the greenhouse gas water vapour does down to the surface with the dry adiabatic lapse rate. In reality without greenhouse gases the emission height would be at the surface and it would thus be colder at the surface.
As I commented at Global Warming Solved:
Victor,
Yes, you may well be right and maybe I’m being overly generous here. I live in hope 🙂
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I can understand not wanting to use the term “greenhouse effect” as it was more so a way to generally communicate the science to the public, however, the science of said “greenhouse effect” is pretty accepted. This is quite interesting.
So what possible explanations do we have? (1) Dunning-Kruger: “mistakenly rating their ability much higher than is accurate” while being unable to spot their errors. (2) the appearance of producing scientificy-sounding refutations of climate science will get you attention. (3) You’ve come up with a bunch of hypotheses that wil genuinely shake the scientific world up once they’ve been tested. For (3) to be true, they’d need to be testable. And – as it reads here – they’re still making some basic mistakes (and of course, the existing science *has* been corroborated from every which angle…)
Then there’s also (4), a relation of (2): you’re actually paid to use your knowledge to produce something that looks and smells like atmospheric science but can be used as the basis for a PR exercise claiming “the science isn’t settled”. I used to think that would be paranoid nonsense but I’m starting to wonder.
To the extent that’s true, ATTP, that presents a problem with arguing with them – or at least “being overly generous” as you put it. Personally, I think once it’s been shown that someone is repeatedly evading the known science and seems impossible to pin down on it, one’s generosity should cease and they should be called out for what they are. Not doing that risks playing exactly the “science isn’t settled” game a lot of people want by appearing to show there’s actual room for argument where none exists.
The Big Question: how do you tell someone who’s got a mental block that they’ve got a mental block, without hardening that mental block?
I am wonder whether research into how to get people out of sects can help with science communication.
Dan,
I would typically tend to agree, but I thought I would try something here that I think noone else has every tried. It’s essentially this : “you know that thing that you describe that you say isn’t the greenhouse effect – well, actually, it is!”.
It may not work, but it seems worth a shot.
ATTP, sorry – I certainly didn’t mean to belittle the fantastic work you’re doing. It’s great to take on a site like that and have a permanent record like this. And the question’s still open, as others have asked, how do you really manage to pin down when someone’s engaging with the science with good faith (and the correct assessment of their own capacities)…
Was worth a try, but failed: At my blog the Hockey Schtick wrote:
Dan
Thanks, but it’s alright. I hadn’t really taken your comment as a criticism. I was just clarifying the motivation behind the post.
Victor,
Oh well, it was worth a try. I have just pointed out on Twitter that 255K/[-g/Cp] is 25.5 km, not 5km, so we’ll see how that goes.
If they could recognise that the process they describe is actually the greenhouse effect, and if they could recognise the consequences of this realisation, it could be quite an epiphany. Wouldn’t it be great to undergo such an epiphany?
I was going to offer the old advice about not counting your chickens before they are hatched. Then I read through the comments and saw that the all-too-predictable outcome had already happened.
Magma,
Feel free to offer the advice you were going to offer. If you think you can convince me that the greenhouse effect doesn’t exist, though, I wouldn’t count your chickens before they hatch 🙂
The paleoclimate issue demonstrates one of the useful and interesting things about science, how everything is related. Thus a solution and investigation into one area is of use in others.
However this massively raises the bar for new explanations of how things work, and in the example on this blog post much time could be wasted trying to make the new theory explain the paleoclimate.
Guthrie,
I agree and I think this is something that many don’t realise. For example, why didn’t most climate scientists suddenly start studying the “pause”? Probably because all other evidence suggested that it was most likely some kind of transient variation rather than an indication of a fundamental problem with climate models or with our basic understanding of the climate.
Factor of five error? A mere trifle, easily discounted by great scientific minds. 🙂
I’m surprised that by now no one has referenced Lysenkoism, basically a form of D-K, wherein politics drives the science. Put a little state power behind such people and they have all sorts of fun.
As far as I know there’s no evidence for the Connollys or the HS proprietor being paid to do this stuff, but for the former especially I would point to the precedent of the Idso family.
Speaking of the latter, Anders, it might be interesting for you to have a look at Sherwood Idso’s “natural experiments” purporting to disprove the GHE on various levels. (Maybe SoD has at some point?) This stuff has a long history. .
guthrie
But it might be entertaining to watch. A bit like those competitions where people build “flying machines” and run them off the end of piers to see what happens next.
Oh wait, “Second Law of Thermodynamics revealed to be a hoax perpetrated by ecoterrorists”. All bets are off.
My personal guess, why scientists did not study the hiatus before, is that it is so tiny. I had never expected that we would be able to give an explanation for such a minimal deviation.
We had a temperature deviation of 0.6°C before science was more or less comfortable with stating that that was mainly due to greenhouse gases. Here science is supposed to make a statement about a deviation of about 0.1°C. I had not expected it to be possible to make somewhat confident statements about something so small.
Now that people realise it is possible, we get paper after paper on the topic. That is was, illustrates how much better our observations of the ocean and atmosphere are nowadays and how accurate the models are by now.
Anders, it occurs to me (without having read their comments), that THS and Ronan Connolly are using GHG to mean Well Mixed Greenhouse Gases, and that they would argue that the altitude of effective radiation is set by water vapour. That would be inconsistent, and should they seriously attempt to model such a system, would not give the results they expect – but if you keep things superficial enough might sound plausible.
That last is the key to all AGW “skeptic” theories. Keep things superficial. Sufficiently superficial that they lead to no further experimental tests than the observations that originally motivated the theory, and even then ensure those observations are described with a sufficient lack of detail as to ensure they are not an empirical test.
To get things going, here’s one of Sherwood Idso’s early contributions (from 1983):
Eerie, innit? In the immediate aftermath of the Charney report, when atmosphere physicists saw danger, one courageous plant scientist sensed a business opportunity.
@-“Uh, no, I’ve already explained dozens of times, as has Ronan Connolley, that the 33K “greenhouse effect” is entirely explainable by the basic physics of gravity, atmospheric mass, pressure, heat capacity and has nothing whatsoever to do with CO2.”
If the ‘explanation’ predicts the surface temperature on Venus, Mars and Titan without arbitrary modification they can collect a Nobel next year..
Tom.
They’ve never made that specific argument as far as I can tell. THS certainly thinks that water vapour cools because it produces a negative lapse rate feedback, reduces dT/dz, and hence reduces the surface temperature. What this seems to ignore is that increased water vapour would also produce a radiative forcing that should increase the effective emission height. It’s all rather confused – to be honest – although I will say that THS has remained pleasant for longer than most “skeptics” with whom I’ve had discussions.
Steve,
I’ll have a look at that. Would be interesting to see the argument.
Surely the point is not whether man made CO2 effects global warming but whether the minuscule amount of man made CO2 (<0.28% of all greenhouse gasses) is so insignificant it cannot measurably effect global warming..
Philip,
I’ve no idea if the 0.28% is right or not, or relevant or not, but the answer to your question is that most credible and relevant science suggest that it does indeed effect global warming. You’re getting sufficiently close to denial that you should probably be cautious about what you say in future comments.
Anders, this post has some context and links to the main thread of the arguments in the literature. Unfortunately, as most of this was pre-internet, very little is public access.
That’s a well-done blog, BTW, one that I had somehow missed and you appear to have as well. I see that it’s not even on Sou’s blog roll, which is a surprise.
andthentheresphysics says:
February 28, 2014 at 6:03 pm
Magma,
Feel free to offer the advice you were going to offer. If you think you can convince me that the greenhouse effect doesn’t exist, though, I wouldn’t count your chickens before they hatch
Oh, not at all. I was simply not optimistic about the possibility of an epiphany among those who have spent years denigrating climate science in such fashion. I have a strong suspicion that most are actually psychologically incapable of doing so. They have invested too much time, energy and venom and are too deeply committed to turn back now. And frankly, if they were evidence-based they would not be writing most of the nonsense that they do.
Eventually, I suppose, they’ll be relegated to the fringes of crankdom (admittedly the fringes can be large, if the example of evolution in the US is any guide) and their numbers will diminish with the passage of time.
Magna, oh sorry, I think I may have mis-interpreted your comment. Yes, you are almost certainly correct, but I still haven’t quite had all the optimism knocked out of me yet. It is close though 🙂
Philip: “the minuscule amount of man made CO2 (<0.28% of all greenhouse gasses)"
… or possibly more like 20%, not counting feedbacks? p.s. that’s No. 103 on the most-common skeptic argument list, well done for finding an obscure one!
Oo sorry – used to be 280ppm, now ~400ppm, makes man-made C02 a measly ~10%. Or, not far off a coupla orders of magnitude higher.
Dan, that is 20% of the effect, not 20% by particle count. By particle count (which is what Philip intends to refer to), anthropogenic CO2 represents about 5% of all greenhouse gases including WV, with WV representing about 80%, and “natural” CO2 about 12%. He probably gets <0.28% because "natural" CO2 represents .28% of the total atmosphere, and CO2 concentrations have not yet doubled; ie, he is probably assuming that all gases are greenhouse gases.
Of course, next Philip will be explaining to us what a small proportion of total gas through flow is provided by gasoline in internal combustion engines, and proving thereby that internal combustion engines would work almost as efficiently with no fuel 😉
How much influence 0.28% can have.
The term “non-condensing greenhouse gas” is used because water vapor establishes equilibrium relatively quickly (on the order of weeks) while CO2 stays in the atmosphere for centuries. Before the 1800s, there were roughly 4 kg of CO2 over every square meter of Earth’s surface. That ~4 kg/m^2 raised Earth’s average surface temperature by ~33°C. If somehow all water vapor were removed, the oceans would evaporate faster, restoring the balance within weeks. But if somehow that ~4 kg/m^2 of non-condensing CO2 were removed, Earth’s surface would cool by even more than ~33°C because the extra ice of a new Snowball Earth would reflect more sunlight.
We’ve raised CO2 from ~4 kg/m^2 to ~6 kg/m^2 at a rate that is unprecedented in at least the last 300 million years.
Anyone who seriously thinks that doubling CO2 would somehow cool the surface might want to explain how Snowball Earth(s) thawed. A frozen planet has a very high albedo and very little water vapor. Geothermal or volcanic heat isn’t enough, and the young Sun was dimmer. But since ice would cover the usual CO2 sinks in the oceans and rocks, volcanic CO2 would slowly build up in the atmosphere.
But if that CO2 somehow cooled the surface, how would Earth ever leave a Snowball state? Also, wouldn’t Venus’s surface be cooler than Mercury, which has no “cooling CO2” and is darker and closer to the Sun?
(After wasting time “discussing” Venus at WUWT, I must sadly point out that pressure doesn’t cause long-term equilibrium heating. Energy does. Otherwise basketball players would have to dribble with gloves because the pressurized ball would have to be very hot.)
@ Victor Venema:
That’s a great video from Dan Miller, with beautifully clear and simple exposition. It may have been around for four years but I’ve never seen it before.
In my experience debating this issue with denialists, there are two types of folks: folks with a very limited understanding of even basic Phys101 level material who are simply convinced that AGW isn’t happening because it’s politically inconvenient (it is, after all, the very definition of a collective action problem for which it seems the market isn’t providing a collective action solution on a fast enough pace), and folks with a bit more understanding who figure they can convince a bunch of the former types with classic Gish Gallop exercises.
In either case, I’m pretty skeptical there’s any reaching of either category, as their commitment to their political ideology is going to trump their ability to reason just about every time.
People like THS are probably somewhere in between the two categories, I suppose.
For obvious reasons my blogging efforts are directed at an entirely different subject, but this issue is simply getting too critical to ignore, and there simply isn’t a sidelines for any of us to sit this out upon.
“you know that thing that you describe that you say isn’t the greenhouse effect –well, actually, it is!”
This whole discussion reminds me of this exchange:
Owner: Good morning, Sir. Welcome to the National Cheese Emporium!
Customer: Ah, thank you, my good man.
Owner: What can I do for you, Sir?
Customer: Well, I was, sitting in the public library on Thurmon Street just now, skimming through Rogue Herrys by Hugh Walpole, and I suddenly came over all peckish.
Owner: Peckish, sir?
Customer: Esuriant.
Owner: Eh?
Customer: ‘Ee, ah wor ‘ungry-loike!
Owner: Ah, hungry!
Customer: In a nutshell. And I thought to myself, “a little fermented curd will do the trick,” so, I curtailed my Walpoling activites, sallied forth, and infiltrated your place of purveyance to negotiate the vending of some cheesy comestibles!
Owner: Come again?
Customer: I want to buy some cheese.
——–
It’s remarkably similar to denialists’ objections to the use of the word “acidification” to describe the lowering of ocean pH due to increased CO2 absorption.
It’s about time we had a contest to find a new phrase to describe that thing in the sky wot causes warming on the ground like.
Looks like people have been around the barn with Shtick before, and to no avail.
ATTP,
The Hockey Schtick asked (from Victor’s comment above):
“Would you agree that Earth’s surface temperature would be about:
255K without an atmosphere
288K with the current atmosphere
304K with an atmosphere of the same mass, without any greenhouse gases [approximated using the observed dry adiabatic lapse rate of 9.8K/km * 5 km = 49K + 255K = 304K]”
In reply you said, “Oh well, it was worth a try. I have just pointed out on Twitter that 255K/[-g/Cp] is 25.5 km, not 5km, so we’ll see how that goes.”
From Tsurf = Teq + h dT/dz which is Teq + h*[g/Cp] = Tsurf you get:
255K + 5km * 9.8K/km = 304K.
Why do you divide 255 by 10 to get 25.5 km?
This exercise indicates that Tsurf will be larger with an atmosphere of the same mass, without any IR absorbing gases compared to no atmosphere. Notice that using the “environmental” lapse rate of 6.6 K/km gives Tsurf = 288K. The environmental lapse rate is attributable to the addition of water vapour compared to the dry lapse rate. So, by extension, addition of IR absorbing gases to the atmosphere lowers Tsurf.
I think it would be worthwhile defining the “g-word” effect so that it distinguishes between these possibilities:
1) An Earth-like atmosphere without IR absorbing gases compared to no atmosphere.
2) An atmosphere with IR absorbing gases compared no atmosphere.
3) An atmosphere with IR absorbing gases compared to one of equal mass without IR absorbing gases.
4) A future atmosphere with greater amounts of IR absorbing gases (aka an enhanced effect).
Chic,
Because on a later Twitter exchange THS claimed the height was 255K/[-g/Cp]. Later corrected.
Here’s what you and THS don’t seem to be willing to accept. The are two properties that we can calculate easily. The equilibrium non-greenhouse temperature (255K) and the adiabatic lapse rate (-g/Cp). Of course we can agree that the environmental/average lapse rate is 6.6K/km. However, we still can’t define our atmospheric temperature profile because we need to also have a height associated with a temperature, which we don’t have. All we have is one temperature (255K) and the temperature gradient.
So, THS seems to think that the effective emission height can somehow be determined from what we already know, but it can’t. The effective emission height (the height at which the atmosphere is 255K) is set by the GHGs. Without them, the surface would be 255K and that would set the temperature at the base of the atmosphere. As we add greenhouse gases, the surface is unable to directly radiate to space and instead the energy is radiated from within the atmosphere. As we add more greenhouse gases, the altitude of this emission rises.
So, in our atmosphere, our effective emission height is about 5km. This is set by the GHGs and we cannot determine this height purely from thermodynamics. Then we can use the lapse rate (6.6K/km x 5km = 33 K) to determine how much warmer the surface will be.
David,
Yes, I should probably have guessed that people had tried, and failed. before.
ATTP,
The concept of effective emission height may be helpful for many but confusing to others. People who don’t know much on the real details seem often to interpret that something specific should be observed at that altitude in addition to the temperature of 255K, and that applies both to skeptics and those who are at early state of their learning without any skeptic preference. More specifically they expect that explaining the influence of extra GHG should be linked to some radiative change specific to that altitude. Such expectations are diffuse, but their prevalence may hinder more correct learning. It should be easy to accept that having 255K at a higher altitude means that the atmosphere is warmer, but that tells nothing on the role of GHGs in raising that altitude.
The more immediate consequence of adding GHGs is the resulting net forcing, and that should be somewhat easier to understand correctly. The main obstacle to many is to understand, how adding GHGs to the upper troposphere does not add but decreases the outgoing radiation. They note that those layers emit more without understanding, how tightly that’s linked to reduction in the radiation from below getting through, and that cold air above warmer air and a warmer surface of high emissivity leads unavoidably to reduction in outgoing radiation.
When it’s accepted that extra GHGs lead to a net forcing, it should be easy to understand that warming will take place until the temperature has risen enough to restore energy balance at TOA. Combine that with fixed lapse rate, the lowest order description is complete.
One potential source of confusion is the role of tropopause in this discussion. Whether the tropopause moves up, and to what extent, with added CO2 has little influence on the net forcing or on the warming of the troposphere needed to restore balance. It’s natural to expect that tropopause goes up during the warming, but the temperature profile near tropopause may change in a more complex way. The influence of that on the surface warming is, however, small. Most of the changes in height of point of emission of OLR occur within troposphere, but some in stratosphere. The IPCC definition of radiative forcing is defined for balance at tropopause. Thus stratosphere is handled differently from troposphere in calculation of radiative forcing, but both are included in further calculations of warming.
Pekka,
I agree that it’s much more complicated and that really it’s related to an increase in radiative forcing. However, I would argue that anyone with a basic understanding of science and maths should understand that one can’t draw a straight line on a graph if you only have a gradient and an x-value. You need the gradient and a data point (x, y). So, what I’m trying (and failing) to do is get some people to recognise that all they’ve actually worked out is a temperature (Teq) and a gradient (lapse rate). To actually determine the temperature profile, you need to be able to associate that temperature with a height, and that is where the radiative forcing comes into play.
“Tom.
THS and Ronan Connolly are using GHG to mean Well Mixed Greenhouse Gases, and that they would argue that the altitude of effective radiation is set by water vapour.
They’ve never made that specific argument as far as I can tell. THS certainly thinks that water vapour cools because it produces a negative lapse rate feedback, reduces dT/dz, and hence reduces the surface temperature. What this seems to ignore is that increased water vapour would also produce a radiative forcing that should increase the effective emission height.”
YET, the tropopause lowers over convective cells? An effect that has been measured (some time ago) locally, and regionally as well as seasonally in the tropics. Further studies would confirm it happens elsewhere, and it has been observed (quite dramatically, and some time ago) along weather fronts in the mid latitudes.
Is the increase in effective emission height associated with increased water vapour only “observable” in the climate models?
“The are two properties that we can calculate easily. The equilibrium non-greenhouse temperature (255K) and the adiabatic lapse rate (-g/Cp).”
“The equilibrium non-greenhouse temperature (255K)” Is that the bare earth model predicted surface temperature?
Has that been tested within the scientific method? If not, it is pseudo science. Shame it is relied upon so heavily then…
Derek,
I’ve seen your description of the greenhouse effect, and it is horribly flawed. I’m not really that interested in more discussions with people who think the greenhouse effect doesn’t exist. They’re wrong.
Derek,
If you measure the outgoing spectrum of the Earth, I believe that one can show that the amount of energy the Earth radiates into space averages to be the same as a blackbody with a temperature of 255 K. So, the answer to your question I, I believe, yes.
“Earth radiates into space averages to be the same as a blackbody with a temperature of 255 K.”
Err, obviously, correlation is not necessarily causation. I say obviously because earth is a grey body. Nor is the explanation you give testing the “theory” within the scientific method.
How can a bare earth have oceans, and their specific heat, ie, heat retention and later release? Slow to heat, slow to cool.
How can a bare earth have an unlit hemisphere at 0 degrees Kelvin????
Earth is not an imaginary black body, therefore the bare earth model, which is a black body model, can not be tested within the scientific method. QED it is pseudo science.
Derek,
I’m not going to start this kind of debate with you. It’s absurd. Nobody’s referring to a bare earth model in the sense that you seem to think. Go and read Stoat’s recent post about the the idealise greenhouse effect and its enemies. You might learn something.
ATTP,
I wrote
trying to imply much that you wrote in your answer. Furthermore I don’t think that this is the source of the disagreement as at least THS and Ronan Connolly seem to agree on this.
The rest of my comment was related to your stated difficulty and to your final sentence
What I was trying to offer is some thoughts on, how that message could actually be made understandable. To address your last sentence the link between the GHG concentration and the radiative heights must be made understood and difficult to deny.
My last paragraph was written to tell that it’s better not to discuss the altitude of the tropopause as that’s not an essential factor, but leads only to minor corrections to the result.
To present consistent arguments we must have a good understanding on what’s important and what’s not. Otherwise we may argue using wrong arguments even when the conclusion is correct. Using wrong arguments offers for the other opportunities to show that the arguments are weak. After that even the right arguments can be more easily dismissed. Good arguments may be explained in further detail, when needed. That’s not possible with weak arguments. The complexity of a fully detailed description leads easily to the selection of arguments that are not the best and most defensible ones.
People, who agree with the main stream science, have a wide variety of ideas on, how to explain GHE best. Most ideas are simplifications that miss some very essential factors. That makes them weak arguments in the sense of my above paragraph. Such arguments may be helpful for people willing to accept the argument knowing that it’s not complete, but they fail when presented to people who rather search for weaknesses in them. That happens even with people, who are ready to accept solid arguments. Those, who have many years of history of not accepting main stream thinking, cannot usually be influenced by any means.
Pekka,
And my answer was me telling you that, in the context of this discussion, I disagree with you. There are lots of ways we could discuss this. If it was people who accepted the basics, then we wouldn’t be having this discussion. We would all be happy discussing radiative forcings and how they influence the atmospheric temperature profiles and the surface temperatures.
Given that this post was motivated by a discussion with people who seem to deny the influence of radiative forcings, I don’t see how introducing them into the discussion helps – in this particular case. It seems fairly straightforward that there is a very basic inconsistency in their arguments. They’re either using the surface temperature to determine the effective emission height, or using the effective emission height to determine the surface temperature. There’s a circularity to their arguments. One would hope that they would recognise this circularity. One would, however, probably be mistaken. However, given that that is what motivated this post, that’s what I’ve trying to do.
Of course, you’re right that ultimately it’s about radiative forcings and that ultimately these people are unlikely to be infuenced by any of these arguments. That might, however, suggest that there really isn’t any good way to discuss this topic with such people. Hence, I’m trying this way for the moment. It will almost certainly be fruitless, but that’s not really the point.
ATTP,
When we have a situation, where no approach seems to work, it’s quite common that people trying to make the same point disagree on the most essential reason for the failure.
Different arguments are needed in different situations. When nothing works the choice doesn’t matter, but we have other cases, where the choice does matter and differently in each case. One is what we see in typical teacher – student case:
– The student trusts that the teacher is right, and the problem is in making the arguments understandable to the student.
Another case is that of convincing a somewhat skeptical person, who is, however, ready to listen to arguments, and to accept them, when he doesn’t find holes in them. There are quite a few such participants in the climate discussion. They are often well educated, and that makes them think that they can recognize valid arguments, when the see them. They wouldn’t perhaps think so about string theory, but the atmosphere appears to them simple enough to understand, or complex in such a way that scientists are not essentially more competent in drawing conclusions than they themselves.
My thoughts concern largely influencing people I discuss in the above paragraph. Influencing them may be quite important, because they influence often in turn other people in contact with them. They are typically capable of asking further questions, and it’s important that this has been anticipated in formulating the original arguments.
The long history of HST tells that he doesn’t belong to either of the above groups, on Ronan Connolly I don’t know, but I’m not really optimistic.
The easiest thing to figure out of the influence of additional GHGs is the immediate forcing. The assumptions are well defined and rather easy to explain. The full calculation of forcing is relatively straightforward. Therefore I consider it the best first step. It has also the advantage that estimates of forcing are readily available and not particularly controversial, at least when only forcing due to GHGs is considered.
Pekka,
I, too, am not that optimistic.
Again, I agree. Certainly, if I was trying to explain this to someone who was simply interested and did not know much about it, this is probably what I would do. Given that I don’t think I am, in this current circumstance, I’m simply trying something slightly different. I’m not optimistic that it will work, but it seems worth a shot 🙂
ATTP,
I haven’t had time to read the entire thread so apologies if this point has been raised before:
I think that talking about an “effective emission height of 5 km” obscures a really important detail, which is that the actual emission height depends on wavelength, and the efficiency with which various greenhouse gasses absorb/emit at that wavelength, and the concentration of said greenhouse gasses.
For visible light, for example, the emission altitude is ground level, unless clouds (and perhaps aerosols) get in the way.
At 15 microns, however, the emission altitude actually punches into the stratosphere (from memory) because CO2 absorbs very strongly at that wavelength. So an alien whose eyes were only sensitive at 15 microns would see the Earth as an uninteresting, fuzzy ball (much like Venus looks to us) and, were they to land, would find themselves wandering around in a dense fog. Whereas astronauts from space have no problem seeing the surface of the Earth between the clouds!
In fact, it was this exact problem that the US Air Force were trying to solve with their heat-seeking missiles 60+ years ago; there’s no point making a heat-seeking missile that can only see a couple of metres past the end of its nose because you made the mistake of making it sensitive to 15 micron infra-red light!
This same property is used by weather satellites to examine the atmosphere at different altitudes, explained nicely here.
So anyone whose “explanation” starts by assuming an emission altitude of 5 km and working their way down needs to explain not only why the effective emission altitude is 5 km, but why the actual emission altitude at different wavelengths depends on greenhouse gas concentrations!
JasonB,
Yes, I agree. That’s why I had included a link to Eli’s post in my post. So, yes, it does depend on wavelength, but I’m really just trying to illustrate that if you want to determine the temperature profile in the troposphere, you need a lapse rate, a temperature and the height at which it is that temperature, and that height is set by the greenhouse gases (although, as you rightly say, there isn’t a single emission height). So, I was keeping it simple so that those I was discussing this with elsewhere might recognise this subtlety – it hasn’t worked so far 🙂
Dan, Tom,
The figure of <0.28% came from the total amount of greenhouse gasses in the atmosphere including W V and man made contributions and adjusted for global warming potential.
Try eating 0.28% of your body weight in LSD and come back to us afterwards with your claims that miniscule amounts of stuff can’t have large effects …
BTW, Hardy, arguing from personal incredulity is a recognized logical fallacy.
As is argument from ignorance. We got a twofer here.
Philip Hardy:
No, it did not. You may think that it did. The GWP of Oxygen, however, is zero. Likewise that of Nitrogen, and Argon. That is 99.96% of the dry atmosphere with a GWP of zero. Of the remaining 0.04%, 0.012% is anthropogenic CO2, with a GWP of 1 (by definition of GWP). That means anthropogenic CO2 represents 30% of the GWP atmospheric composition of the dry atmosphere.
Tom,
Your numbers don’t seem right. Man made CO2 is about 4% of all CO2 in the atmosphere and about 0.2% of all greenhouse gasses including water vapour. These approximate numbers are often stated and seem to be generally accepted by climate scientists.
That’s not correct. Much more than 4% of the CO2 presently in the atmosphere originates from fossil fuels. Most of that has not been in the atmosphere all the time since the release, but alternated between the atmosphere, near surface ocean, vegetation, and top soil.
But the correct value for tha above is totally irrelevant, what’s significant is the anthropogenic contribution to the CO2 in the atmosphere, and that’s about 30% of the total present concentration.
In the last sentence one word is missing. It should read “.. to the amount of CO2 ..”
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Pekka Pirilä,
The main misunderstanding (or misconstrual) behind the strange ‘climate physics’ idea of a ‘real’ effective radiating level somewhere in the atmosphere from which to climb down (?) the lapse rate ladder to set the surface temperature, is simply this: There is a distinct physical temperature tied to Earth’s radiative flux being measured from space. There isn’t. The atmosphere is a dynamic, many, many kilometers thick volume of gas, not one solid black body surface with absorptivity/emissivity = 1. The planetary flux to space is a total flux, an accumulated, final flux made up of the contributions from ALL atmospheric layers AND the physical surface at the bottom. It is not tied to any real temperature. The temperature 255K is simply calculated from knowing the flux and applying the Stefan-Boltzmann equation to it. Only IF the Earth did have one solid black body surface where all energy were absorbed and from where all energy were emitted, would this connection bear any meaning. It doesn’t. Earth simply needs to rid itself of as much energy over a certain period of time (a day, a year) as it absorbs from the Sun to be at balance. 239 W/m^2 IN, 239 W/m^2 OUT, both fluxes through the ToA. And it regulates this through convective processes and hence tropopause height.
Kristian,
Really? You think it some kind of attempt to mislead? Yes, of course we’re not emitting as a single temperature blackbody. That’s why I linked to Eli’s post showing the actual outgoing spectrum and how different regions in wavelength space come from different heights. It’s just a way to explain the basic idea. If you’re one of those who sees ways of explaining things using simplifications as attempts to mislead, this could be your one and only comment here.
Er, ATTP, where precisely in my post do I write anything about there being an attempt to mislead?
If you’re one of those who build straw men to tear down as soon as they see an argument they perceive as ‘hostile’ and so reflexively want to dismiss it the simplest way possible rather than attempting to digest what it’s actually saying (you have not addressed at all what I’m pointing to – try reading it again and try for instance to ponder the following: Where does that iconic 33K GHE value come from? What specifically stated relationship is it based upon?), then yes indeed, this could very well be my one and only comment here.
Kristian,
You used the term “misconstrual” which may not immediately imply intent, but is not a term I would typically use if I was intending a good faith discussion. Plus, given how I actually linked to a post that illustrated the outgoing spectrum of the Earth, specifically to address issue that you raised, I find comments like yours somewhat irritating.
I think I have addressed your comment, in a number of places. If you’re genuinely interested in a serious discussion, why don’t you read some of the other posts, some of the comments that have been made and make another comment that tends to being more pleasant and conducive to an interesting discussion. If you can’t be bothered doing that, feel free to make these your only comments.
Just for the record I also initially read ‘misconstrual’ as implying a deliberate intent to mislead (or possibly to mislead oneself). The FreeDictionary definition is:
and the contrasting with ‘misunderstanding’ in Kristian’s post suggested an additional meaning, which would be the ‘deliberate’ part in my view.
Philip Hardy, although you have already been corrected by Pekka, allow me to use an example of the incorrect thinking. If not for you, then at least for others.
Suppose you own a shop that has an annual turn-over, after taxes, of 100,000 pounds. Your annual costs for stock, renting the shop, maintenance and salaries are also 100,000 pounds. Your shop’s bank account has a slight buffer of 10,000 pounds. Maintain this shop for a few years, and your bank account will continue to have 10,000 pounds on it.
Now you go into an agreement with someone who wants to place a slotmachine in your shop. You get 10% of its turn-over, which happens to be 3,000 pounds (again, after taxes). The rest is for the person who placed the machine there – he also has all the associated costs.
What will be on your bank account one year later? 13,000 pounds
(unless you increase your spending and do not sell more thanks to that slotmachine – let’s assume neither happens).
Another year later it is 16,000 pounds. Yet another year later you have almost doubled the amount on your shop’s bank account (19,000 pound).
When somebody then asks you how you managed to double the amount of money on that account, what will your answer be?
a) “Almost all of that is thanks to the turn-over of my shop”
or
b) “All of that increase is due to the slotmachine”
You can compare this to the CO2 in the atmosphere as follows: your annual turn-over of the shop is the CO2 coming from natural sources. Your annual costs of the shop is the CO2 being taken up by natural sources. The slotmachine’s contribution is the CO2 from anthropogenic sources.
What’s the effective radiative temperature? Where can it be seen or measured?
It has only one real meaning. It can be determined by measuring the overall OLR flux and solving for temperature from Stefan-Boltzmann law. Looking at the radiation in more detail and applying Planck’s law it has no role. It’s one measure of the total OLR flux, it’s not the temperature of any specific point, nor an average temperature.
What’s the effective radiative altitude?
It’s an altitude which has according to some formula the temperature of effective radiative temperature. That formula is some agreed formula that represents more or less correctly the average atmospheric profile.
To me it’s clear that such a doubly indirectly determined concept is confusing to many, while I know that many others like the concept even though probably only a fraction of the latter really understand what it is.
Pekka,
Agreed.
Quite possibly true. However, trying to go into more detail so as to make the definition clearer will then confuse another group of people. One thing I maintain is that we can spend all eternity discussing the best way in which to explain a complex topic. I’m certainly not claiming that the way I’ve chosen to do so here is the best way and I doubt it will be the only way in which I would choose to explain this topic. It just happens to be the way I’ve chosen to do so here.
Teaching inherently complex concepts and finding the right balance between simplification and “over”simplification will always be difficult. It can especially be difficult if you have to teach something you know is ‘wrong’, but where the more correct (but not necessarily quite right) is likely to lead to even more confusion for the not-so-well-informed. Then again, those who know a little bit more may well complain it is wrong.
Case-in-point: the structure of an atom, and in particular the “orbitals” of electrons. Imagine starting your explanation with wave functions for various orbitals, rather than with Bohr’s atom model…
ATTP,
Different people have different ways of thinking. What’s intuitive for one is not for another. Therefore difficult issues must often be explained in several different ways to help a larger number of people. Unfortunately a large number of alternative explanations is also confusing. They all are simplifications and thus not fully correct in all respects. I don’t think that this dilemma can be fully resolved, but recognizing its presence and taking that into account is surely helpful. It’s essential that we do not conclude automatically that another person is wrong, when (s)he thinks differently from ourselves. Only when the concrete conclusions differ from what we feel sure about, can we conclude that there’s an error somewhere in the logic.
Even when there surely is an error in the logic, it can be resolved only when the correct step is identified rather than another, where only a legitimate difference in the way of thinking is present.
Perhaps the following example clarifies a little, how added CO2 affects the height of emission of radiation that exits the atmosphere. (Referring to my previous comment, this might be helpful for some, but not for all.)
I made some calculations using my slightly modified version of SoD’s radiative transfer code implemented in Matlab. I calculated the altitude profile of the point of emission of radiation that that exits at the top of atmosphere. In this graph I show four results out of those calculations. Two of the curves represent a band in the short wavelength tail of the CO2 absorption peak, the other curves give the distribution for all IR. The influence of CO2 is most significant in the tails of the CO2 peak.
We can see that about 37% of all radiations originates at the surface. This high value is due to the properties of the 1976 U.S. Standard atmosphere, which I used in my calculation. It’s a clear sky case and the atmosphere is relatively dry. A tropical standard atmosphere would be quite different even for the clear sky conditions.
The U.S. standard atmosphere has an almost constant lapse rate up to 12 km, and a zero lapse rate in the range 12 – 20 km. Above 20 km the temperature starts to rise, but using the same temperature profile for both concentrations does not make sense as adding CO2 would lower the temperature there very rapidly. That change affects also the distributions shown on this graph a little as the share of the upper stratosphere is exaggerated in this plot for the 800 ppm curves.
From the two upper curves we see that 50% of the escaping radiation of the CO2 tail is emitted below 4 km with the present CO2 concentration, but only 37% with 800 ppm. To reach 50% with 800 ppm we must include all altitudes up to 6.7 km. Summing all wavelengths the change is smaller but still significant. It’s large enough to result in a forcing of 4.8 W/m^2 (determined from upwards flux at 15 km, to exclude the influence of the error in handling the upper stratosphere). The forcing is this large, because the clear sky U.S. standard atmosphere is not equal to the average case.
The effective radiative temperatures of the two cases are 260.5 K (for 400 ppm) and 259.3 K (for 800 ppm). Effective radiative altitudes are 4.26 km and 4.44 km. Again these values apply only to clear sky U.S. standard atmosphere.
The curves tell about the immediate change after a sudden increase in CO2 concentration before any change in temperature has had time to develop on the surface or in the atmosphere. That leads to warming until the OLR flux is in balance with SW warming. The effective radiative temperature changes only little due to the warming in the clear sky case. Thus a new balance would be reached when the temperature at 4.44 km is approximately as high as it was at 4.26 km before the addition of CO2. Thus both the surface and the troposphere would warm by approximately 1.2 K.
The reason I like analogies/metaphors is that they simplify the explanation you’re attempting to make and put it in a context with which others can identify; yet there’s no danger a genuine reader will confuse the simple analogy with the complexity of the real thing.
Of course, the pseudosceptics invariably use the tactic of pushing analogies to the point they break and then claiming it’s proof the real thing is broken too! But then the pseudosceptics are not the people the analogy is aimed at: they’re entrenched beyond hope. Luckily most people reading a pseudosceptic’s response will recognise the tactic.
ATTP, I realise the word ‘misconstrual’ might hold different connotations to different people; mine are not ones of malice or intent.
But that aside, I hope it’s possible on this site to discuss differences of opinion. And a difference of opinion is what I would like to discuss with Pekka Pirilä here (and/or you or anyone else).
I happen to think that the whole notion of an ‘effective radiating level’ (ERL) somehow controlling Earth’s surface temperature downward via the lapse rate is based on fundamentally flawed concepts of how the surface/atmosphere system actually operates.
It is purely a theoretical way of ‘explaining’ Earth’s mean surface temperature as being above what it should’ve/would’ve been without a GHG atmosphere. But this is a claim. Nothing else. We know Earth would’ve been a colder place without an atmosphere altogether (just look at the Moon), so the atmosphere surely does something. But we do not know that it would’ve been a colder place with an atmosphere, but without GHGs. That is only a claim. I can think of explanations that would make it hotter in such a situation. This would also be a claim. Both claims are based on what processes you choose to focus on, which processes you think are the most important.
So the whole ‘ERL + lapse rate controls/sets surface temperatures’ idea is a ‘writing desk hypothesis’. It looks good on the blackboard, on paper. But that’s it. There is no empirical backing anywhere to claim with any real scientific credibility that somehow because of something called an ‘elevated ERL’, the physical temperature of our planet’s solid surface is so and so. It is just a claim, backed up solely by theoretical arguments.
That is my opinion. You (and Pekka) most likely have another one. And so I am willing to discuss it. Am I allowed to?
Kristian,
Differences of opinion are fine. How one frames such a difference is the issue. I can’t write a longer response now, but will do so if Pekka or someone else doesn’t.
The radiative properties of CH4, CO2 etc are not “claims”.
Science does not deal in opinion or counterfactual claims.
Just an aside, but GHE denial – aka “sky dragonism” is even banned at WUWT.
Kristian,
Maybe you could explain – so as to avoid lengthy discussions that don’t go aware – how an atmosphere can warm the surface of an Earth-like planet, without the Greenhouse effect.
Kristian,
There are issues on which we all have our legitimate opinions. I would classify some parts of your writing to that. There are, however, also issues, which have been studied by science, and on which science can tell answers that are virtually certain (virtually, because all results of science can be contested, even those that are considered absolutely certain in normal parlance).
The essential role GHGs have in having an Earth that has a surface temperature about 33 K higher that that derived from intensity of solar radiation, albedo, and the Stefan-Boltzmann law belongs is an issue that is virtually certain based on the well known science of physics.
The albedo has been measured, it’s not based an theory, and calculating the value accurately from theory and locally measured properties of the Earth subsystems would be difficult. The temperature profile is also based on measurements. The basic mechanisms that lead to approximately such profile are known, but calculating exact profiles is extremely difficult due to the many factors that affect real profiles (time of day, condensation, clouds, horizontal mixing, and still some more). The IR absorption and emission properties of atmospheric gases have been both measured and calculated by quantum mechanical calculations. That implies also that the basic theory of emission and absorption in gases is theoretically well defined as well as thoroughly tested by experiments.
Calculations like to one behind my curves are fully based on the reliable input listed above, no further assumptions are needed. Concerning the GHE only one conclusion is possible:
The surface temperature is controlled by the requirement of
– the overall energy balance,
– the temperature profile of the atmosphere, and
– the absorption and emission properties of the atmosphere.
The last point includes both clouds and atmospheric gases, and calculations show the large role of GHGs in that.
My curves are the result of such an calculation for a specific clear sky case. The full calculations of climate scientists like Myhre include contributions from different parts of the globe and various states of cloudiness. Even the single clear sky case tells semi-quantitatively the result, but cannot give correct quantitative values.
Kristian writes:
and follows up:
To this the short response is, it is absolute unmitigated nonsense. Just because Kristian does not know the experimental basis of the theory does not mean it does not exist. And that he assumes scientists base so fundamental a theory on just theory shows an appalling arrogance. He pretends he knows better than the physicists because he has read (if typical), one or two blog posts by people with no demonstrated understanding of the science.
In this case the theory he has not bothered understanding is based on two aspects – ie, the existence of an environmental lapse rate governed by convection, and the release of latent heat by precipitation. I assume that even Kristian will not pretend there is no observational basis for the fact that the atmosphere gets cooler as you get higher within the troposphere. So, the question that remains is is the radiative physics well confirmed? I refer him to the 134,862 observations (a small fraction of all relevant observations) which I have previously mentioned. Those particular observations were made by satellite instruments, but similar observations have been made from aircraft from a large variety of altitudes, with both “look up” and “look down” instruments, and of course, from the surface with “look up” instruments.
Sorry, missing link :
http://www.skepticalscience.com/basics_one.html#76028
Lacking proof-reading again. The word belongs should be removed from the second para. On first line of 3rd paragraph an should be on. 4th paragraph to one should be the one (A couple of lesser ones in addition.)
When do I learn to proof-read the comments before submitting?
The same place I learn to head mine with the name of the commenter I am addressing 😉
Kristian says: “we do not know that it [Earth] would’ve been a colder place with an atmosphere, but without GHGs. That is only a claim. I can think of explanations that would make it hotter in such a situation.”
There certainly are reasons why a planet like Earth could have pretty much any temperature you choose for a short period of time. The scientific issue is in the steady state, with a certain amount of energy coming in from the Sun (and a tiny amount more from radioactive decay in Earth’s interior), and the same amount leaving, what will the temperature be?
The only way energy leaves the planet is through electromagnetic radiation. If Earth had an atmosphere “without GHGs”, that means all that outgoing radiation must come from Earth’s surface. Given the various physical parameters involved, those facts imply the average temperature must be equal to or LESS than 255 K.
Or do you dispute some of these facts? Whatever the atmosphere does, if it has no components that absorb and emit infrared (like GHGs) then it cannot radiate energy to space.
“But we do not know that it would’ve been a colder place with an atmosphere, but without GHGs. That is only a claim. I can think of explanations that would make it hotter in such a situation. This would also be a claim. Both claims are based on what processes you choose to focus on, which processes you think are the most important.”
And straight down the rabbit hole we go.
How very, very convenient it is to think that our GHG emissions aren’t doing anything important.
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BBD says, March 4, 2014 at 2:46 pm:
“The radiative properties of CH4, CO2 etc are not “claims”.”
I’m not talking about ‘the radiative properties of CH4, CO2 etc.’ Those are not claims. The claim that these radiative properties act to make the surface of the Earth warmer.
andthentheresphysics says, March 4, 2014 at 2:59 pm:
“Kristian,
Maybe you could explain – so as to avoid lengthy discussions that don’t go aware – how an atmosphere can warm the surface of an Earth-like planet, without the Greenhouse effect.”
Thanks. And yes, I will. But it will require some space and time. So a bit later.
Kristian,
It follows. That’s one of the fundamental aspects of the greenhouse effect. If you have radiatively active gases in the atmosphere, they act to trap outgoing radiation. That means that the surface cannot cool directly to space. In order for the planet to be in energy balance, the surface temperature must be higher than it would be in the absence of greenhouse gases.
The problem with this discussion is that the existence of the greenhouse effect is really not disputed and any discussion about it is largely pointless unless the goal is simply to understand it better. A discussion about whether or not it exists is really not worth the effort.
Tom Curtis says, March 4, 2014 at 3:20 pm:
Tom, your whole post reeks of the very arrogance you accuse me of. AND you link to SkS. Those two points alone make you a person I will not bother having a discussion with on this subject. I much prefer Pekka’s more equable tone.
andthentheresphysics says, March 4, 2014 at 9:26 pm:
“If you have radiatively active gases in the atmosphere, they act to trap outgoing radiation. That means that the surface cannot cool directly to space. In order for the planet to be in energy balance, the surface temperature must be higher than it would be in the absence of greenhouse gases.”
The atmosphere heats from below primarily through conduction>convection and evaporation. These processes occur regardless of any radiation. In other words, GHGs are not a prerequisite for a warm atmosphere. If there were no GHGs in the atmosphere, the atmosphere would STILL be warmed by the surface (energy would be transferred) through convective processes. BUT, it couldn’t cool radiatively to space. In other words. It’s not the GHGs that ‘trap’ energy from the surface. It’s the 99.5 % of the atmosphere that can’t emit IR at earthly temperatures that ‘traps’ energy from the surface – all the heat brought there through conduction/convection and evaporation.
The GHGs enable the atmosphere to cool. They don’t enable it to warm.
Pekka Pirilä says, March 4, 2014 at 3:16 pm:
Pekka, thanks for your reply. I will answer you later.
Kristian,
But here’s the fundamental problem. If there are no GHGs, the surface radiates directly to space. That means that the average amount of energy that the surface loses per square metre per second must be the same as a blackbody with a temperature of 255 K. If the average temperature exceeds 255 K, then the average amount of energy it radiates into space will exceed the average of a 255 K blackbody. Therefore the surface would cool. The only way the surface can avoid cooling down until it emits as much energy per second per square metre as a 255 K blackbody is because of the greenhouse gases in the atmosphere.
Convection and conduction can’t help you because if they were effective at cooling the surface (which they aren’t, I don’t think) the surface temperature would actually be even lower than an average of 255 K.
Actually, this may be wrong. If there are no GHGs then I think the surface has to settle to a temperature so that it radiates as much energy per second per square metre as a 255 K blackbody.
True, but this radiation can be achieved in different ways, resulting in different average surface temperatures. Arthur Smith placed the correct limit (255K) on Earth’s average surface temperature without greenhouse gases (keeping albedo constant as always) and also correctly noted that the average surface temperature could be less than 255K.
An atmosphere without greenhouse gases couldn’t warm Earth’s surface past 255K, but it could conduct heat from equator to poles, and from dayside to nightside. Even a pure N2 atmosphere would reduce these temperature extremes through conduction, and the Stefan–Boltzmann law’s nonlinearity would warm the average surface temperature up to a limit of 255K for a perfectly conducting atmosphere, where the equator, poles, dayside and nightside are all exactly 255K. Reducing temperature extremes by increasing the surface heat capacity results in a similar phenomenon (with a different albedo).
But again, an atmosphere without greenhouse gases couldn’t warm Earth’s surface past 255K. Anyone who claims otherwise should answer Arthur Smith’s question on March 4, 2014 at 6:59 pm.
Kristian:
“The GHGs enable the atmosphere to cool. They don’t enable it to warm.”
Not again. Please.
Kristian,
I’m not going to accept anymore comments on this thread that deny the greenhouse effect so think carefully before making another comment if you don’t want it deleted.
How could they not?
What dhogaza said.
[This comment has been removed by the moderator]
andthentheresphysics says, March 4, 2014 at 9:49 pm:
“If there are no GHGs, the surface radiates directly to space.”
True. But it cannot radiate as much to space as it receives from the Sun. And thus it gets warmer and warmer and warmer. In this situation it can never reach an equilibrium state.
“That means that the average amount of energy that the surface loses per square metre per second must be the same as a blackbody with a temperature of 255 K.”
No, because the Stefan-Boltzmann law does not include convective loss. It pertains to a purely radiative situation. But this is not a purely radiative situation. The surface will always lose absorbed solar energy through conduction > convection whenever there’s an atmosphere on top of it, it happens naturally and automatically, and hence this energy is transferred to the atmosphere rather than being radiated to space directly from the surface. In the atmosphere it cannot be radiated away. So it piles up.
OK, so I was not allowed to discuss my particular difference of opinions with Pekka on this site. Noted. You’re one of those sites.
Well, then there’s no more point for me staying, is there …?
Nope.
Kristian:
“OK, so I was not allowed to discuss my particular difference of opinions with Pekka on this site. Noted. You’re one of those sites.”
It is sort of like saying “you’re one of those textbooks. Physics textbooks. No point in my reading them, is there? Or taking upper-level physics courses. Or listening to physicists. The voices in my head are all I need”.
So, right, no point in your staying here. Go visit the perpetual motion “physicists” and the like. You’ll find kindred spirits. [Mod: Last sentence removed; disrespectful]
The Stefan-Boltzmann law does not include conductive loss. It pertains to a purely radiative situation. But this is not a purely radiative situation. The surface will always lose absorbed solar energy through conduction whenever there’s rock (or any substance other than a perfect insulator) under it, it happens naturally and automatically, and hence this energy is transferred to the rock rather than being radiated to space directly from the surface. In the rock it cannot be radiated away. So it piles up. And thus it gets warmer and warmer and warmer. In this situation it can never reach an equilibrium state.
Actually, this is why all planets just get warmer and warmer, never reaching an equilibrium state. One corollary is that life doesn’t exist.
Kristian: Listen to Steve Bloom.
In the mean time, I just want to let you know that I just built some optical energy absorption equipment for measuring green house gasses. You can pick up some excellent old text books on how to do this.
Not much has changes since Tyndall 1861. We’re just a lot more accurate about it.
Click to access tyndall-1861.pdf
“[Mod: Last sentence removed; disrespectful]”
Why does Kristian deserve respect?
Particularly after you made this statement:
“I’m not going to accept anymore comments on this thread that deny the greenhouse effect”
And yet, we find a statement from Kristian that implies just that, posted before you moderated my comment.
Don’t make empty threats. Either don’t accept such comments by Kristian, or don’t huff and puff and say that you won’t when you do.
dhogaza,
Why does Kristian deserve respect?
Because it’s in the comment policy to treat other commenters with respect.
And yet, we find a statement from Kristian that implies just that, posted before you moderated my comment.
Yes, I acknowledge this and thought about deleting it but I would also have to delete DumbSci’s comment now which is quite funny. Do people want me to do this? I will be diplomatic and go with the consensus on this 🙂
Thanks. I’d vote, but life doesn’t exist so why bother.
Life. Don’t talk to me about life…
You don’t get to vote, DumbSci as you have a conflict of interest.
There are no conflicts of interest in a lifeless universe.
And I don’t really mean to talk about life. Life is really just an incidental detail which doesn’t exist because all planets get warmer and warmer, never reaching an equilibrium state, until their rock vapor attains escape velocity. The same principle also applies to stars because they technically also absorb starlight.
Therefore only black holes, dark matter, and nebulae exist. No life as we know it (except possibly for Xeelee and photino birds), so no conflicts of interest.
dhogaza: Always offer respect no matter what you think of them. Let the comment policy weed out the silliness.
Dumb Scientist: I saw a great talk about space on Saturday night. This astrophysicist spends his entire life studying… nothing. Yup. What’s in all that empty space? And how big is it?
If a scientist tripped over a rock in the deep void, would anyone care?
Rachel (moderator?). My comment that you deleted was a reply to Pekka Pirilä. Would it not be a good thing to have him see it and answer it? (I can indeed go elsewhere to have this discussion with him, SoD for instance, which has a more sober comment policy than you do – discuss differences of opinion rather than just deleting the ‘wrong’ ones off hand. Much more educational for everyone.)
It simply looks very bad with direct censorship of all reasoned, but unwanted arguments. It makes this site look like an echo-chamber for the initiated just like so many other warmist sites (like SkS, Tamino and the like).
Kristian,
The problem is that the greenhouse effect exists and is why the surface of the planet is 33K warmer than it would be in the absence of an atmosphere with radiatively active gases. Even SoD doesn’t dispute this. If you don’t understand why, I (or others) would be happy to explain it. However, a discussion about whether or not it exists, really isn’t worthwhile. It’s not about opinion, it’s about science. You can call it censorship if you wish, but being prevented from posting incorrect science on my blog is not actually censorship as it doesn’t prevent you from posting it elsewhere. Also, using terms like “censorship”, “warmist” doesn’t really help to make me feel that we should be allowing you to post here. The sites you mention happen to do a very good job of explaining the science associated with global warming. That you don’t seem to understand this may well be quite telling.
ATTP,
Wow. Just wow! Echo chamber it is, then. Good luck with that …
ATTP, you’d be happy to explain, but not willing to discuss your explanation.
That is not science, ATTP. That is dogma. I’m sorry.
Kristian,
Absolutely happy to discuss the explanation. Not really willing to consider that there is no greenhouse effect. It doesn’t make sense and typically means that one party doesn’t understand what we mean by the greenhouse effect. Maybe you could at least illustrate that you have some self-awareness by recognising that an accusation of “dogma” followed by no longer being welcome somewhere is a reasonable outcome.
I have defended tolerance to differing views, and I have written that we should not conclude too eagerly that some specific comment is totally wrong, but I have also written that that approach has its limits. Most certainly I don’t like being picked by Kristian as supporting the presentation of such views on the basic nature of GHE. I don’t see any reason to continue discussing such ideas on a site like this, when they contain nothing more interesting than refusal to accept well known and indisputable facts.
When questionable or even very likely wrong ideas are supported in a novel way that’s not obvious nonsense discussing them makes sense, but discussing repeated old falsehoods is not of any value.
andthentheresphysics says, March 5, 2014 at 12:28 pm:
“Absolutely happy to discuss the explanation. Not really willing to consider that there is no greenhouse effect.”
Exactly. That means you aren’t willing to discuss it. You’re just telling. ‘This is how it is. Now hold your tongue.’
Not quite. The reality is that I have discussed this a number of times with people all of whom either deny the radiative influence of GHGs or describe the greenhouse effect without realising that they’ve just done so. I just don’t want to keep doing that. It’s a waste of my time. Also, was “no longer welcome” too subtle?
Oh look! A discussion about moderation. How unique!
Aargh! Rachel. Put everyone on moderation except DS (who just won the Internet, above). Then go and have a nice cup of tea.
😉
Kristian you are not being censored. You were given a chance to make your claim which was shown to be lacking. You provided no math evidence and were told to stop speculating unless you had some real science to show. If you can provide some actual scientific evidence of your claim then I think it should be allowed but simply repeating that everyone else is wrong is not evidence. Write it all up with a clear explanation and some math and I am sure everyone would love to read it. Until then you are just making unfounded claims that we have all heard before and proved to our own satisfaction to be incorrect.
prove us wrong.
I wholeheartedly approve of the “censoring” of anti-science graffiti.
Anymore complaints about moderation in this thread will be deleted. Compliments are fine though 🙂
BBD, tea is being drunk. Yorkshire tea too. The absolute best.
That’s the spirit, Rachel. Mrs BBD would agree with you about the Yorkshire tea, I should add.
Isn’t the 255 K limit being discussed based on the currently accepted value of 239 W/m2 emission rate? If there were no IR absorbing gases, there would be no snow or clouds and the SB black body temperature would be more like 278 K equivalent to the average solar insolation of 341 W/m2.
What Kristian is implying is the possibility that Earth would be hotter than 288 K without IR absorbing gases. Certainly, it would have greater diurnal temperature fluctuations. If there is any accumulation of heat due to conduction/convection, the average temperature could approach 288 K or greater.
The effect you are discussing should start with a clear definition of it and then end with an agreement to stop using the term “greenhouse” to describe it.
Chic,
Sure, we’re assuming an unchanged albedo. If there were no greenhouse gases, however, the surface may well gain more ice, the albedo would rise, and the equilibrium temperature would be even lower.
I agree that we should be willing to define what we mean. However, we should also be willing to acknowledge that this is a blog, not a peer-reviewed paper. I also see no reason to stop using the term “greenhouse” effect. It’s not perfect (greenhouses warm more because of a lack of convection) but it’s still just a term and changing it isn’t going to suddenly make everyone agree.
Not to comment on your moderation, Rachel, but I think you and Anders have moderated this thread quite well. Not that I’m commenting on your moderation, of course.
“What Kristian is implying is the possibility that Earth would be hotter than 288 K without IR absorbing gases.” I probably should have written 255K, not 288 K.
No. See Lacis et al. (2012). ATTP is correct: surface temperature would plummet.
Eh? Sometimes my fingers have minds of their own. That should be Lacis et al (2010).
ATTP,
“It’s not perfect (greenhouses warm more because of a lack of convection) but it’s still just a term and changing it isn’t going to suddenly make everyone agree.”
Precisely the problem. There is no lack of convection in our atmosphere. When the surface warms, the air above expands and rises. This is the most basic starting point regarding an atmosphere heated by a sun. The type and amount of IR absorbing gases is an additional consideration. Averages = simplification only complicates reality.
Chic,
I think you miss the point though. The surface warming is entirely a consequence of radiatively active gases in the atmosphere. These gas are often referred to as greenhouse gases. Convection, to a first approximation sets the temperature gradient (lapse rate), the greenhouse gases set the effective emission height. Given a height, a temperature at that height, and a lapse rate, you can determine the surface temperature and hence the amount of greenhouse warming.
Pingback: Effective emission height | And Then There's Physics
This is demonstrably false and I’ll have to let it go on that disappointing note.
I do commend you on your willingness to debate and for keeping your discussions polite. May the forcings be with you.
´Chic,
You have missed the point that convection works against your conclusion, not in support of it. As you describe, it cools the surface, but it cannot reduce the radiation from the surface for a given temperature. Thus it would result in a colder average surface than without convection. We need the back-radiation or DWIR from GHGs to fill the gap. We need also the emission of IR from upper troposphere to space to maintain the convection. Without GHGs you fall goth on surface and in the troposphere.
Pekka,
A meeting of the minds appears possible again. First, please explain which conclusion of mine does convection work against. Second, I agree that convection does not reduce radiation from the surface other than because of a lower surface temperature resulting from a reduction in DWIR from and conduction into the layer of air directly above the surface when it is replaced by a cooler layer from above. Third, I’m not sure what “it” refers to in “Thus it would result in a colder average surface than without convection.”
Fourth, convection will occur whenever an air pocket below is less dense than one above regardless of IR emission from the upper troposphere. Also, please restate the last sentence.
ATTP,
“The surface warming is entirely a consequence of radiatively active gases in the atmosphere.”
This is the statement I was saying is demonstrably false. Surface warming is due to SWIR from the sun and the fact that it isn’t all reflected away. How else would the surface warm in the first place? IR absorbing gases accelerate cooling during the day and impede cooling at night.
Lawyer Chic responds to ATTP as if the latter had said “The surface *temperature* is entirely a consequence of radiatively active gases in the atmosphere.” Meh.
As for the moderation, it’s polite to a fault. 🙂
Meh… And Then There’s Physics is saying that the Green House Effect is a theory… Just like Gravity. Good luck convincing the scientific community that this really old science is all wrong, and telling them to rewrite the text books. I’ll hold your coat.
http://en.wikipedia.org/wiki/Greenhouse_effect
Interesting Wikipedia makes mention of Tyndall 1861. Definitely a good read to get a basic understanding of the Green House Effect.
Steve,
At 8:17pm, March 5, ATTP said “The surface warming is entirely a consequence of radiatively active gases in the atmosphere.”
Surface temperatures are a consequence of the combined effects of insolation, conduction, convection, radiation, and evaporation depending on the time of day and where on Earth you are. The average global temperature cannot be attributed to any single factor.
The average surface warming above 255K (as per all the above comments) is entirely a consequence of radiatively active gases in the atmosphere.
Rachael:
“Yes, I acknowledge this and thought about deleting it but I would also have to delete DumbSci’s comment now which is quite funny. Do people want me to do this? I will be diplomatic and go with the consensus on this”
If you state that you’re going to delete person K’s comments if person K continues to repeat posts, then person K does so, and you don’t delete the comments, well, then …
Don’t bother ever saying you’ll delete/moderate such comments.
Either path is OK with me, I guess. Just be consistent. Don’t post empty threats. If you draw a line in the sand, enforce it. Either moderate, or don’t moderate … just be clear about it.
Meanwhile, I’m no longer spending much time here. The “GHE does not exist” crowd is tiresome, as are the perpetual motion people who keep trying to convince my that my car will continue running if I no longer put fuel in it.
AnOilMan:
“dhogaza: Always offer respect no matter what you think of them. Let the comment policy weed out the silliness.”
Since you posted that comment, I see four silly posts by Kristian and seven by Chic. Just sayin’.
Yeah, where’s Burl? I miss Burl.
dhogaza: I often wonder whether they agree to work together before they show up, and try to add some air of respectability to what is being said. I always feels as though they are working from some sort of identical strange play book. In the past, it seemed to point to silliness at Watts Up With That.
Chic,
The conclusion that I meant is that convection could somehow help in making surface warmer than it’s without. Only GHG’s and clouds may contribute to a warmer surface than that calculated from energy balance of Earth without atmosphere. If convection could be stopped keeping the GHG and albedo, the surface would be much warmer than it’s now (on the average, not everywhere).
Chic,
Maybe I phrased that badly, but in the absence of radiatively active gases in the atmosphere, the surface temperature cannot exceed that set by a basic energy balance calculation.
Hmmm, may as well ask here, though I doubt it will leave moderation, but why not?
ATTP, what do you think would happen if you removed 99% of the atmosphere, leaving only the CO2/H2O/less common gases.
Since your argument is that N2/O2 have no ability to raise the temperature on their own, removing them should not change the temperature, right?
ATTP has never denied the existence of pressure broadening and the associated enhancement of the greenhouse effect by N2/O2. ATTP also didn’t challenge my explanation that N2/O2 can raise the temperature of the Earth but only up to 255K (via “basic energy balance calculation” at fixed albedo).
Max, you are confusing the fact that the presence of O2 and N2 influences the strength of the greenhouse effect with the idea that there would be a greenhouse effect in a pure O2/N2 atmosphere. That is analogous to looking at a light tower at a football ground and assuming that because the lighting would not be as good if the actual lights were at ground level, therefore the tower itself could light the ground without any lights being installed.
Well, that is one way you could interpret what I said, Tom, but not what I meant.
I’ve gone back and forth with ATTP about this before, and he agreed that dumping a bunch of N2/O2 onto the moon until the surface pressure was the same there as it is at sea level here would at least temporarily raise the surface temperature.
He then thinks the atmosphere would cool until the surface temperature distribution could be averaged out to the black body equilibrium temperature (~270 K for the moon) and that all of the cooling by the surface would be radiative.
In fact O2 and N2 have infrared spectral lines and can indeed take part in radiative cooling–just not as well as CO2/Methane/other gases with available vibrational modes–along with conductive transport of heat from the surface. It seems to me that this presents a dilemma.
If ATTP is correct then the surface will be losing heat through conduction and that energy has to be lost somehow. If it is radiated to space then it will be done from a higher altitude and thus cooler source than the surface, if it is not radiated to space then the atmosphere will just keep heating up until what… it escapes entirely?
If an O2/N2 atmosphere can’t cool at all while it can obviously take part in cooling the surface through conduction, where do those conductive losses end up?
Points on the day side of the moon would heat up towards the peak of ~390 K, presumably the atmosphere would come into contact with this surface at some point, and presumably it would end up undergoing an increase in temperature, wouldn’t it?
If the newly heated air from the day side was not able to effectively cool by radiating it away into space, it would need to lose that heat by conduction after the surface cooled sufficiently for this to take place.
This temperature inversion and relaxation probably wouldn’t occur as rapidly as the surface normally cools overnight, as air is not the best source of conductive heat transfer, making the night time cooling a race between subsurface/atmospheric heat transfers to the surface and surface radiation to space.
Supposedly this would take place sufficiently rapidly for the night time temperature to wind up low enough that the day time heating would not lead to an increase from the black body equilibrium temperature, which means a rather thick blanket of N2/O2 would wind up being nearly indistinguishable from a vacuum?
If that is the case, then removing the N2/O2 from our atmosphere shouldn’t change the temperature much if at all, as their contribution is negligible, right?
Similarly, if the CO2/H2O in the atmosphere are all that matters, then dumping the 3 trillion or so tons of CO2 in our atmosphere and let’s say another 6 trillion tons of CO2–because trying to work out exactly how much water vapor there is and what all the interactions involved are is a pain–all given time to relax after the work was done of course, should give a temperature quite a bit higher than the over 5 quadrillion tons of N2/O2 (needed to give 1 bar pressure under lunar gravity) would, right?
Or swap our atmosphere with that of Mars, we end up with 25 trillion tons of CO2, Mars ends up with ~5 quadrillion tons of N2/O2 and ~3 trillion tons of CO2.
I’m pretty sure we’d be on the losing end of that trade, but apparently I’m confusing “lightpost” for the “lights” huh?
Max,
Adding an atmosphere of N2 and O2 on the moon cannot have much influence on the average of the T^4 (fourth power of the temperature). The effect is as small as the share of the radiation absorbed. Thus the main effect would almost certainly be a slight cooling due to absorption of UV in the atmosphere. About half of that absorbed energy would radiate to space from the upper atmosphere rather than warm the surface through any mechanism.
The atmosphere would reduce a little the temperature differences between different parts of the surface. Therefore the average temperature (average(T)) would increase a little, while the average(T^4) is constant. This effect is, however, very weak, because the atmosphere cannot warm much the cooler parts, and therefore cannot cool much the hotter parts either. It cannot warm much the cooler parts, because emission of IR is the only efficient way atmosphere can transfer heat downwards to a cold surface.
With a very weak (but nonzero) emission and absorption of radiation the atmosphere has a strong inversion near surface over most of the planet. Above that layer of inversion the lapse rate is close to the adiabatic lapse rate up to the tropopause, which would be at an altitude of something like 30 km, perhaps even higher. On the moon the adiabatic lapse rate would be about 1.65 K/km, and that combined with the relatively warm lower troposphere would result in such a tropopause height. On the other hand a relatively dense atmosphere would extend hundreds of kilometers up to produce the surface pressure of about 1 bar.
The lower tropopause just above the inversion layer would be much warmer than the average surface temperature as it would be warmed by convection from the warmest area, but cooled very weakly elsewhere.
All in all, the surface temperatures on the moon would not change much by such an atmosphere. not for the average, and not even locally or between night and day. (Another issue is that moon would start to lose gas from that atmosphere rather rapidly due to the weak gravity and heating of the top layers by UV.)
Max,
I think you’re treading a fine line here. You asked a bunch of questions, which I attempted to answer. You’re repeating them back in a way that doesn’t quite represent what I was trying to get across. The strength of the greenhouse effect depends on the radiative strength of the gases in the atmosphere. I’m sure N2/O2 are not completely radiatively inactive, but their impact – as Pekka indicates – on the surface temperature would be small.
Max,
Ignoring that we would no longer be able to breathe, without water vapour the GHE would be smaller. Also, without the other gases (as DumbSci pointed out) there be much less pressure broadening and so the greenhouse effect of the CO2 would be less than it would be in the presence of the other gases. Given that the CO2 on Earth contributes 20 – 30% of the greenhouse effect, this would mean that a Mars-like atmosphere on Earth would probably produce less than 8 degrees of warming. That’s just a quick guess though.
I know you think that there is no GHE on Mars, but I do not think this is quite correct. My understanding is that there is, but it is quite small. About 6 degrees.
Pressure broadening is a very important factor. I made two comparison runs with linewidths that were 10% and 1% of the real ones keeping otherwise the U.S. Standard atmosphere unchanged.
With 10% linewidth the OLR at TOA increased by 39 W/m^2 and with 1% lienwidth by 77 W/m^2. Changes in DWIR at surface where even larger reductions in the warming of surface.
Various sources on Mars temperatures list a range between 200 K and 220 K for an average, the black body temperature expected for Mars sits at 210 K. I will note that most of the higher values for Mars I found were older data, more recent sources give it as ~210 K, naturally this will depend on how you average, which sites you use, which data sources are incorporated, and so forth.
Not that it matters much but simply taking the min and max gives a mean of ~206 K for Mars, while Earth gives ~259 K and 210~220 K for the Moon.
More relevant, I think, is that the pressure around 30~35 km is similar to that on Mars, and the temperatures there seem to fall between 210 and 240 K everywhere I look.
Pure CO2 or not, dropping the air pressure to that found in the upper tropopause and maintaining a temperature over 260 K here would be quite a trick.
Hmmm, if the (N2/O2 @ 1 bar) atmosphere can not help cool the hotter sections of the Moon, wouldn’t that mean said atmosphere should be very close to the same temperature?
Conductive losses by solids immersed in a fluid are determined by temperature differences and distance. The distance drop off is significant, but poking around with a calculator gave me some values to work with:
Using the air conductivity value given and working with a 1 m^2 area at 117 C, assuming the air 1 cm above the surface was ~10 C the conductive losses would be 255 W/m^2.
Going the other way, if the air was at ~10 C and the night side dropped to -70 C the calculator spits out a number of -190 W/m^2, which may be outside the values where the assumptions work, though it is still using the same values for thermal conductivity of air.
So either the peak daytime surface temperatures could get the air warm enough that it no longer lost hundreds of W/m^2 through conduction, and said warmed air could apparently supply potentially hundreds of W/m^2 to the surface at nighttime lows… or for some reason the physics of air conduction wouldn’t apply any longer?
This is ignoring convection/pervection of course, but that is why I chose a height of 1 cm, to represent a boundary layer of air just above the surface being warmed during the day or warming the surface during the night.
Max,
Except I don’t think you’d do that. You average the energy lost (per square metre per second) and then convert that to an effective average temperature.
I’m not sure I get the rest of what you’re saying. I find similar temperatures to you (about 210K) for Mars and find that the actual average surface temperature may be around 215K, hence around 5K of greenhouse warming.
I don’t get the rest of what he’s saying either, but interaction is likely pointless. The linked site advanced the astroturfer hick hypothesis after I tried to explain the greenhouse effect.
Max,
Yes. It would mean that the temperature of the atmosphere just above the inversion layer would be close to the temperature of the warmest part of the surface. That warmest part would be the only place without an inversion layer.
I cannot tell, how thick that inversion layer would be far from the hot spot. Telling that would require a rather extensive model based calculation.
Assuming that the strength of the inversion is 0.1 C/m, the conductive flux is about 0.0025 W/m^2. As the convective flux of the hot region is easily tens of watts per sq meter, we see that 0.01% of the area could supply the heat that warms the remaining 99.99% really weakly. The implied 25 W/m^2 would be less than 2% of the power of the sun at zenith, and thus a rather small effect locally, while the heating by 0.0025 W/m^2 is really negligible.
Inversion of 0.1 C/m would mean that a temperature difference of 100 C would require an inversion layer of 1 km.
The above numbers are meant only to explain the basic idea. They are certainly significantly off from what the real values would be.
You’re calculating conduction across too large of a distance. Over distances greater than a meter you’re entering the realm where convection is going to dominate.
Conductive transfers are most effective over short distances, understandably, and they are driven by the difference in temperatures across said short distances.
Trapping a thin layer of warm air near your skin does a good job keeping you warm. Running around in a fabric bubble a meter across would not keep you very warm.
Air doesn’t have impressive thermal conductivity, but cold enough air close enough to your skin is going to wick heat away pretty quickly.
Now, the lunar surface heats up to 300~390 K during the day and drops to 100~200 K over night.
Using the assumptions that the atmosphere would not be heated through IR absorption, and for simplicity ignoring solar heating in the hypothetical N2/O2 atmosphere, we have some conflicting properties which need to fit together for ATTP’s position to hold up.
The atmosphere can’t be heated effectively by the surface, and it can’t heat the surface effectively.
If this is the case then the air at the surface should be pretty cold, and I can’t think of a reason why a situation which should dramatically increase the effectiveness of surface -> air conductive heat transfer could be compatible with the assumption that said atmosphere has a negligible effect on the surface temperature.
If it is not cold near the surface, then it must be due to conductive heating as it this is a “non-radiatively active atmosphere” being discussed, right?
If it can be heated through conduction, then it stands to reason that overnight whenever the surface began to dip below the temperature of the atmosphere–an atmosphere which does not readily shed heat through IR emissions–the surface would begin cooling the atmosphere, which I am pretty sure means it couldn’t cool at the same rate it would (radiating into a vacuum directly) while it is also acting as a heat sink for the atmosphere.
Just because an atmosphere has poor IR absorption, that does not imply that it is unable to engage in heat transfer, does it?
Max,
This isn’t my position. It’s mainstream science’s position.
I think this is roughly why you get inversion layers. If the surface can cool faster than the atmosphere above it, then the temperature profile can be shallower (less negative) than the lapse rate. In such a circumstance, the atmosphere would be convectively stable. The only way to change this is for the atmosphere to be heated by the surface. However, if there are no GHGs in the atmosphere then this becomes quite tricky as the surface would radiate its energy directly into space and the atmosphere would – I think – tend towards being isothermal.
I, however, don’t see much point in continuing this discussion. You don’t seem to believe the greenhouse effect exists. Most other scientists disagree. I disagree. We’ve discussed it in quite some detail without really get anywhere. I plan to call it quits.
Max,
The convection does not dominate, when there’s no convection. That’s the case in the inversion layer. Therefore strong temperature inversion can develop rapidly under suitable conditions. Such conditions are familiar for me from winter time Lapland north of polar circle. It’s common to have there the situation that the temperature is -25 C at low altitudes, but only -5 C just 100 m or 200 m higher on the hillside. Such conditions develop mainly at night but they may persist for much of the day.
Pekka,
My mother’s side of the family hails from Rovaniemi. I was under the impression that the only people foolish enough to brave the winter in Lapland were silly Japanese tourists. I guess I’ll have to add wayward physicists to the list 🙂
kippis!
I’m not discussing cold conditions where inversions develop when I speak of convection taking over. On the day side the temperature profile should start out at whatever the competition between radiative cooling and conductive heating allows the surface to reach, with the atmosphere temperature being determined by the ability for an inversion to set up overnight, cool the surface, and upward distribution of heat through convection above the developing inversion layer.
Once morning breaks you start getting energy pumped back into the system, the inversion formed overnight is no longer energetically favored and should tend back towards a convectively dominated profile as the temperature of the surface reaches and surpasses temperatures further up.
Once the surface temperature begins to increase significantly above that of the atmosphere it should begin losing heat more rapidly by conduction to the layer directly above the surface, which then heats up, expands, and begins convecting that heat upwards.
If there is no easy radiative route for the atmosphere to shed heat during the day, and there is no simple way to explain the surface temperature dropping below that of the atmosphere until evening approaches, then I’m not sure why the idea that the atmosphere should not heat up persists.
Note that this is not even taking into account the rather quicker form of mechanical energy transfer discussed by the Ronan and Michael.
Oh, isothermal states for dense gas columns in a gravity well have lower entropy than one where temperature decreases with height, as that profile is the one which natural moves towards an isentropic state.
When density/pressure fall below a certain level you start to see isothermal states emerge until they both drop too far or you get stratosphere/thermosphere development at altitudes where ozone or N2/O2 heating by sunlight (soft and hard UV respectively) dominates all other processes.
“determined by the ability for an inversion to set up overnight, warm the surface”
“the rather quicker form of mechanical energy transfer discussed by the Connollys”
Whoops.
Max,
I wrote a lengthy response to Ronan’s recent comment om Global Warming Solved and then lost it and can’t be bothered writing it again there. I’ll try to explain it here, but I am starting to lose both interest and patience.
One thing that Ronan is stressing is that the temperature profile depends on the thermodynamic properties of the gas and not on the presence of trace GHGs. This is roughly correct, so I largely agree with this. The problem, though, is that although the thermodynamic properties tell you what the profile should be (temperature gradient) they don’t allow you to determine an actual temperature.
So, how do we determine an actual temperature structure? We also know that on average the planet must radiate as much energy back into space as it receives. This is 240 Wm-2 (assuming the same albedo as now) and is equivalent to a blackbody with a temperature of 255K. Now if there’s no atmosphere, all of this energy must be radiated from the surface.
Now consider adding an atmosphere. As we’ve already agreed, I think, the thermodynamic properties of the atmosphere (in the troposphere at least) means that atmosphere must have a lower temperature than the surface. The presence of radiatively active gases in the atmosphere means that some of the energy must be radiated from within the atmosphere (and some from the surface). However, since the atmosphere’s temperature is lower than the surface temperature, the surface temperature must – on average – exceed 255K or else the total amount of energy radiated could not match that of a 255K blackbody.
The more GHGs there are in the atmosphere, the more energy that is radiated from within the atmosphere and the higher ths surface temperature must be. This is the greenhouse effect. It’s a combination of the thermodynamic properties of out atmosphere and the influence of radiatively active gases.
As far as I can tell, what Ronan describes is essentially what I’ve described above and what you say makes me think that your views aren’t dissimilar. Certainly Ronan is essentially describing the greenhouse effect, but somehow thinks that it’s all thermodynamics and that the radiatively active gases don’t play any role. Well, they don’t play much of a role in setting the temperature gradient, but they do play a role in setting how much energy is radiated from within the atmosphere and hence what the actual temperature is and, consequently, what the surface temperature.
Anyway, I think that’s the last time I plan to try and explain this, so if you want to believe the greenhouse effect doesn’t exist, carry on.
Max,
You introduced the case of atmosphere of N2 and O2 for the moon. That’s a case of extremely small but not exactly zero absorptivity/emissivity. The little absorptivity comes from the microwaves related to rotational states of O2, trace amounts of ozone and oxides of nitrogen, and other special cases. This little absorptivity is enough to maintain a troposphere that has over most of it a lapse rate very close to the dry adiabat. (With exactly zero absorptivity no real troposphere would be maintained and most of the atmosphere would become isothermal at a high temperature.)
With zero absorptivity and with the extremely weak absorption the only efficient heat transfer mechanism is convection. Convection from surface is initialized when the air at some point of surface has the potential temperature higher than the potential temperature in the nearby atmosphere. There are, on the other hand, no effective ways of cooling the atmosphere. Conduction is needed for the cooling. The weakness of such cooling is what the calculation I presented in an earlier comment tells, as an inversion is always present, when the atmosphere is warmer than the surface.
We have one effective mechanism to warm the atmosphere and no effective mechanism to cool it. That results in warming of the atmosphere until it’s so warm that the total warming flux is reduced to a value equal to the total cooling flux elsewhere. In this situation the air close to the surface (but above the inversion layer) must be almost as warm as the hottest spot of the surface with sun near zenith. With zero absorptivity most of the atmosphere gets isothermal at that high temperature. With nonzero, but very weak absorption and emission only the lowest atmosphere above inversion gets that hot, while the lapse rate is adiabatic up to the tropopause, and less than adiabatic above. Beyond some altitude (tropopause or higher) the temperature starts to increase due to heating by SW.
All those qualitative features seem clear to me, but the height of the inversion layer at various location is something that I don’t know. My guess is a maximum of the order of 1 km neglecting the influence of topography (mountains), but that’s only a guess. That could be determined by a model of the remaining weak circulation at low altitudes. That model should calculate also conduction, which an essential part of the heat transfer under those conditions.
Indeed, barring the isothermal bit (an edge case anyways which could only apply in unphysical gases that do not interact with radiation at all, though I still think isentropic rather than isothermal is the state that would emerge), this is what I was saying. assuming the reasoning there is sound, we can work out something else.
The situation on the night side should no longer resemble the vacuum scenario. The colder the surface becomes the more effective it becomes at cooling the atmosphere, which would prevent the surface from reaching the same lows overnight.
It would also reduce the equator to pole temperature gradients.
At this point, I’m not sure how to take this scenario and wind up at one which is very similar to the vacuum scenario temperature distribution.
Max,
While I agree that The colder the surface becomes the more effective it becomes at cooling the atmosphere, I think that it would remain so ineffective in cooling the atmosphere or being warmed by the atmosphere that it would stay almost as cold as it would be without any atmosphere at all. That’s the point of my simple calculation in a comment above.
Your inversion calculation is looking at the situation after the surface has already begun warming the atmosphere, is it not?
As you said, if there is a 100 K difference in temperatures and a 0.1 K/m gradient the altitude in question would be 1 km above the surface.
If this is the case then you’re already assuming the surface has warmed the air to nearly the same temperature.
If the surface is getting close to the 390 K peak, then the atmosphere would need to be near the same temperature in order for conductive losses to drop off to inconsequential levels.
If said < 390 K atmosphere is unable to cool by itself, then each night you get a very hot atmosphere sitting over a surface which is trying to dump heat into space.
If the surface is ineffective at keeping the night side warm, then the night side temperature will drop to a point far below that of the atmosphere, at which point you would need to postulate some mechanism to explain why something which normally improves the rate of conductive heat transfer (a large temperature difference over short distances, as is the case for a very hot atmosphere sitting on a very cold surface) instead has little to no effect.
Essentially you propose the same surface temperature profile with an atmosphere that remains at or near 390 K at all times, and is somehow unable to influence the distribution of surface temperatures at all.
I’m pretty sure if I were laying down during a calm night on the moon while the atmosphere all around me was even remotely near 390 K I would not fare too well, whether the surface was cool or not.
Max,
Yes, I’m really discussing an atmosphere that’s hot immediately above the surface and the inversion layer, where that exists.
What makes you think that such an atmosphere would not fare too well?
Nothing cools it much anywhere, nothing warms it much anywhere. There would be some winds due to the uneven thickness of the inversion layer, but the rate of remaining warming at the (moving) hot spot, the compensating cooling elsewhere, the circulation, and the thickness of the inversion layer will reach a stationary state. I cannot tell the quantitative properties of this stationary state, but I do believe that it’s calm with weak circulation, and the temperature profiles I have described.
When someone notifies you they checked the instruments to see if the atmosphere obeys Ideal Gas Law
and it still does
after people told you for twenty years, it still does,
when for that same twenty years people have also been telling you the atmosphere actually has it’s thermal profile assigned by Green House Gas Law/Theory of weighting it
that isn’t ”we’re almost on the same page.” That’s “You believed in magical laws that don’t actually exist, whereas the scientists who discovered you’re clueless about what determines atmospheric thermal profile continue on their
working scientific atmospheric chemistry
and you blog that you thought James Hansen and Michael Mann were honest men. Honest.
And that “you thought the basic science was sound.”
LoLoLoLoL.
No, you’re just now finding out about the first law of the simplest phase of matter
being the first one broken
by James Hansen’s “Infrared Global Warming” models.
The ones he switched on you for the real ones called by real science the “Infrared Global Cooling”
model.
That’s what the actual case is, Hansen’s own fellow employees warned us about it before Hansen ever became the head of G.I.S.S.
He said they had dementia.
The only ones it turns out, who have dementia,
are the ones furiously looking high and low for that Green House Gas Infrared Warming Law.
James,
I’m having some trouble understanding what you’re getting at in your comment.
and you say, “sure, why wouldn’t it. Would be quite remarkable if greenhouse gases in the atmosphere changed a fundamental law of physics.”
ATTP, looks like James is trying the “PV=nRT” line. That is, the earth is around 14/15 degrees Celsius because the pressure at the ground is around 1 atm, or so these people believe.
Marco,
Surely he can’t be suggesting something quite that silly, can he? 😉
Those two Irishmen checked instruments measuring the various known aspects of atmospheric disposition. As per orbital calculations for things entering and leaving the atmosphere, the atmosphere’s thermal profile, still obeys: The Ideal Gas Law.
Weighting the atmosphere otherwise is departure from the known fact that molarity matters not species within the atmospheric mixture, regarding thermal profile.
If you don’t know the story of Hansen’s fellow employees complaining about that very thing, that explains why you don’t recognize the term Ideal Gas Law.
PV=nRT is indeed the Ideal Gas Law new guys, the very people knowing James Hansen best accused him of precisely what you saw those Irish guys calculate and establish again for posterity: the thermal profile of atmospheric gas
is governed by Ideal Gas Law.
I was around and in Radiation Communications Electronic Engineering when Hansen [Mod : redacted] on tv, I watched him and Mann both, lie. Hansen claimed there weren’t adequate sensors to put through the tropopause –
that’s what the [Mod : redacted] was before you were around – the STORM system chuffing man made co2 up through the tropopause to have it re settle there and make a thicker blanketing effect.
You don’t know that obviously I can tell just by the way you conduct yourselves, you’re not working scientists you’re college or graduated bloggers talking about science.
Those Connolly guys are right about the Ideal Gas Law being known to govern thermal profile of the atmosphere, that’s all there is to it, and if you don’t like it that defines you as just another wannabe arguing with working atmospheric chemists telling you, atmospheric air’s thermal profile is governed by Ideal Gas Law.
Everyplace you check you’re going to be told that in real science.
In magic gas Hansen/Mann/Anthony Watts signts: not so much.
End of story it ‘s why all you believers can’t debate your way out of a paper bag in physics. You think the Global Infrared Cooling Model
is a Global Infrared Warming Model. “It’s just a matter of how much.”
It’s just a matter of you ever measuring CO2 added to air making it’s temperature rise once.
It’s been raging upward for 15 or 17 years, and temps are actually marginally lowering.
N.O.A.A. checked their own story of backerdistical association. They laid out detectors at ground zero for CAGW for fourteen years between 1996 and 2010,
14 years checking for that big correlation between the backerdistical glitterings and the magical, magical gas.
When NOAA whose STORY this is got through after 800 000 samples,
there was less backerdistical glittering than before they started.
Ideal Gas Law is what the atmospheric thermal profile is governed by, magic gassers.
No, your lack of ability to grasp the first law of the simplest phase of matter doesn’t mean you could have been kind of right and it’s almost the same.
You are and were so wrong you don’t have a Magic Gas Constant after a quarter of a century frantic search because of course it’s not there, but the IDEAL GAS LAW with it’s GAS CONSTANT still applies
in all the gas energy mechanics it ever and always has.
LoL. What a bunch of amateurs. Ideal Gas Law. Learn it.
Yeah my radiation communications Electonic Engineering and work in instrumentation and atmospheric energy transmitting, capturing and analyzing electromagnetic energy through the atmosphere and space and industrial compounds to make that happen mean I know everything you know about it like I did when I was watching Hansen lying on tv.
Were you born then? I was interested because I was thinking I would be applying at N.A.S.A. potentially. Were you listening and remembering what Hansen’s fellow engineers said about him?
And it’s eXACTLY like they said: it’s PERFECTLY OBVIOUS there’s NO CALCULATION for ASSIGNING ATMOSPHERIC TEMPERATURE by TRACE COMPOSITION.
PV=nRT is the law that establishes the thermal profile of atmospheric gas mixtures as can be
simply proven
by telling everyone listening to you whine it just aint true
go Google/Bing “the atmosphere obeys Ideal Gas Law” .
The R in that gas law represents ANY MIXTURE of TRACE GASES WHATEVER THEY MIGHT BE.
End of story except your fervent declarations you haven’t ever measured anything for money but you don’t think people who do, know as much about measuring things as you.
LoL Line up with Michael Mann and James Hansen and Keith Briffa and Tom Wigley and Phil Jones.
They thought they were going to mock reality and not have it mock them back. You’re fronting for frauds, kids face the equation : PV=nRT.
Worked for NASA who taught James Hansen about computer climate models which he then reversed and converted into Infrared Global Warming Models.
James,
Half of what you say seems to be conspiracy ideation.
Indeed, but this is precisely what one would expect from the greenhouse effect.
When I get a chance, I’m going to look through your comments and moderate anything that is libelous.
I have a challenge for you though. If your next comment includes a full and consistent calculation of how you can get the temperature profile and temperature (i.e., not just the gradient) given only our distance from the Sun and the thermodynamic properties of the gas in the atmosphere, I’ll post it and do my damndest to nominate you for a Nobel prize. Otherwise, I’ll just delete it.
Dear James. Explain the temperature of Venus. Love, Physics.
Ideal Gas Law, hick.
Not Magic Gas Law
LoLoLoL. What a f****ng hillbilly.
[Mod : I’ve trashed about 4 or so of your previous comments as they’ve all been of a similar style. I thought I would just post this one so that I could illustrate your commenting style and point out that I plan to save myself time by adding you to my “direct to spam” queue, and giving you the option to avoid wasting your time by trying to comment again. 🙂 ]
i’m surprised no one discusses DTR , this should be the ‘smoking ‘gun’ , i just watched one of those U of chicago lectures, re smoking gun ‘ no mention of DTR. I also think its foolish to deny there is warming as i can see myself where glaciers have melted, the key point is DTR, and there is think the evidence is weak
ziff, the change in DTR is indeed predicted under global warming, but the change observed is much larger than the predicted change, and is primarily to changes in cloud cover and WV concentrations. Because of the magnitude of the additional effect (ie, that due to changes in the water cycle) relative to the predicted effect, it is only very weak evidence that recent warming is caused by a greenhouse effect.
Tom , my point exactly
l”it is only very weak evidence that recent warming is caused by a greenhouse effect”.
what is needed is pure desert data. And there was the BEst ” study showing no change in US ,and other studies showing an increase in last decade just when Co2 is up.
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