By Christopher Monckton of Brenchley
Reed Coray’s post here on Boxing Day, commenting on my post of 6 December, questions whether the IPCC and science textbooks are right that without any greenhouse gases the Earth’s surface temperature would be 33 Kelvin cooler than today’s 288 K. He says the temperature might be only 9 K cooler.
The textbook surface temperature of 255 K in the absence of any greenhouse effect is subject to three admittedly artificial assumptions: that solar output remains constant at about 1362 Watts per square meter, taking no account of the early-faint-Sun paradox; that the Earth’s emissivity is unity, though it is actually a little less; and that today’s Earth’s albedo or reflectance of 0.3 would remain unchanged, even in the absence of the clouds that are its chief cause.
These three assumptions are justifiable provided that the objective is solely to determine the warming effect of the presence as opposed to absence of greenhouse gases. They would not be justifiable if the objective were to determine the true surface temperature of the naked lithosphere at the dawn of the Earth. My post of 6 December addressed only the first objective. The second objective was irrelevant to my purpose, which was to determine a value for the system climate sensitivity – the amount of warming in response to the entire existing greenhouse effect.
Since Mr. Coray makes rather heavy weather of a simple calculation, here is how it is done. According to recent satellite measurements, 1362 Watts per square meter of total solar irradiance arrives at the top of the atmosphere. Since the Earth presents a disk to this insolation but is actually a sphere, this value is divided by 4 (the ratio of the surface area of a disk to that of a sphere), giving 340.5 Watts per square meter, and is also reduced by 30% to allow for the fraction harmlessly reflected to space, giving a characteristic-emission flux of 238.4 Watts per square meter.
The fundamental equation of radiative transfer, one of the few proven results in climatological physics, states that the radiative flux absorbed by (and accordingly emitted by) the characteristic-emission surface of an astronomical body is equal to the product of three parameters: the emissivity of that surface (here, as usual, taken as unity), the Stefan-Boltzmann constant (0.0000000567), and the fourth power of temperature. Accordingly, under the three assumptions stated earlier, the Earth’s characteristic-emission temperature is 254.6 K, or about 33.4 K cooler than today’s 288 K. It’s as simple as that.
The “characteristic-emission” surface of an astronomical body is defined as that surface at which the incoming and outgoing fluxes of solar radiation are identical. In the absence of greenhouse gases, the actual rocky surface of the Earth would be its characteristic-emission surface. As greenhouse gases are added to the atmosphere and cause warming, the altitude of the characteristic-emission surface rises.
The characteristic-emission surface is now approximately 5 km above the Earth’s surface, its altitude varying inversely with latitude: but its temperature, by definition, remains 254.6 K or thereby. At least over the next few centuries, the atmospheric temperature lapse-rate (its decline with altitude) will remain near-constant at about 6.5 K per km, so that the temperature of the Earth’s surface will rise as greenhouse gases warm the atmosphere, even though the temperature of the characteristic-emission surface will remain invariant.
It is for this reason that Kiehl & Trenberth, in their iconic papers of 1997 and 2008 on the Earth’s radiation budget, are wrong to assume that (subject only to the effects of thermal convection and evapo-transpiration) there is a strict Stefan-Boltzmann relation between temperature and incident irradiance at the Earth’s surface. If they were right in this assumption, climate sensitivity would be little more than one-fifth of what they would like us to believe it is.
So, how do we determine the system sensitivity from the 33.4 K of “global warming” caused by the presence (as opposed to the total absence) of all the greenhouse gases in the atmosphere? We go to Table 3 of Kiehl & Trenberth (1997), which tells us that the total radiative forcing from the top five greenhouse gases (H2O, CO2, CH4, N2O and stratospheric O3) is 101[86, 125] Watts per square meter. Divide 33.4 K by this interval of forcings. The resultant system sensitivity parameter, after just about all temperature feedbacks since the dawn of the Earth have acted, is 0.33[0.27, 0.39] Kelvin per Watt per square meter.
Multiply this system sensitivity parameter by 3.7 Watts per square meter, which is the IPCC’s value for the radiative forcing from a doubling of the concentration of CO2 in the atmosphere (obtained not by measurement but by inter-comparison between three radiative-transfer models: see Myhre et al., 1998). The system sensitivity emerges. It is just 1.2[1.0, 1.4] K per CO2 doubling, not the 3.3[2.0, 4.5] K imagined by the IPCC.
Observe that this result is near-identical to the textbook sensitivity to a doubling of CO2 concentration where temperature feedbacks are absent or sum to zero. From this circumstance, it is legitimate to deduce that temperature feedbacks may well in fact sum to zero or thereby, as measurements by Lindzen & Choi (2009, 2011) and Spencer & Braswell (2010. 2011) have compellingly demonstrated.
Therefore, the IPCC’s assumption that strongly net-positive feedbacks approximately triple the pre-feedback climate sensitivity appears to be incorrect. And, if Mr. Coray were right to say that the warming caused by all of the greenhouse gases is just 9 K rather than 33 K, then the system sensitivity would of course be still lower than the 1.2 K we have determined above.
This simple method of determining the system climate sensitivity is quite robust. It depends upon just three parameters: the textbook value of 33.4 K for the “global warming” that arises from the presence as opposed to the absence of the greenhouse gases in the atmosphere; Kiehl & Trenberth’s value of around 101 Watts per square meter for the total radiative forcing from the top five greenhouse gases (taking all other greenhouse gases into account would actually lower the system sensitivity still further); and the IPCC’s own current value of 3.7 Watts per square meter for the radiative forcing from a doubling of atmospheric CO2 concentration.
However, it is necessary also to demonstrate that the climate sensitivity of the industrial era since 1750 is similar to the system sensitivity – i.e., that there exist no special conditions today that constitute a significant departure from the happily low system sensitivity that has prevailed, on average, since the first wisps of the Earth’s atmosphere formed.
Thanks to the recent bombshell result of the Carbon Dioxide Information and Analysis Center in the US (Blasing, 2011), the industrial-era sensitivity may now be as simply and as robustly demonstrated as the system sensitivity. Dr. Blasing has estimated that manmade forcings from all greenhouse gases since 1750 are as much as 3.1 Watts per square meter, from which we must deduct 1.1 Watts per square meter to allow for manmade negative radiative forcings, notably including the soot and other particulate aerosols that act as little parasols sheltering us from the Sun.
The net manmade forcing since 1750, therefore, is about 2 Watts per square meter. According to Hansen (1984), there had been 0.5 K of “global warming” since 1750, and there has been another 0.3 K of warming since 1984, making 0.8 K in all. We can check this by calculating the least-squares linear-regression trend on the Central England Temperature Record since 1750, which shows 0.9 K of warming. So 0.8 K warming since 1750 is in the right ballpark.
The IPCC says that we caused between half and all of the warming since 1750 – i.e. 0.6[0.4, 0.8] K. Divide this interval by the net industrial-era anthropogenic forcing of 2 Watts per square meter, and multiply by 3.7 Watts per square meter as before, and the industrial-era sensitivity is 1.1[0.7, 1.5] K, which neatly and remarkably embraces the system sensitivity of 1.2[1.0, 1.4] K. So the industrial-era sensitivity is near-identical to the low and harmless system sensitivity.
Will the IPCC take any notice of fundamental results such as these that are at odds with its core assumption of a climate sensitivity thrice what we have here shown it to be? I have seen the first draft of the chapter on climate sensitivity and, as in previous reports, the IPCC either sneeringly dismisses or altogether ignores the growing body of data, results and papers pointing to low sensitivity. It confines its analysis only to those results that confirm its prejudice in favor of very high sensitivity.
In Durban I had the chance to discuss the indications of low climate sensitivity with influential delegates from the US and other key nations. I asked one senior US delegate whether his officials had told him – for instance – that sea level has been rising over the past eight years at a rate equivalent to just 2 inches per century. He had not been told, and was furious that he had been misled into thinking that sea level was rising at a dangerous rate.
Having gained his attention, I outlined the grounds for suspecting low climate sensitivity and asked him whether he had been told that there was a growing body of credible and robust evidence that climate sensitivity is small, harmless, and even beneficial. He had not been told that either. Now he and other delegates are beginning to ask the right questions. If the IPCC adheres to its present draft and fails to deal with arguments such as that which I have sketched here, the nations of the world will no longer heed it. It must fairly consider both sides of the sensitivity question, or die.
Couple of things here.
First, the Earth’s albedo is not 0.3, it is 0.37 as has been measured multiple times by NASA. However, this is a planetary average as is Chris’s measurement of the average watts/m2.
http://www.asterism.org/tutorials/tut26-1.htm
It still bothers me, trying these simplistic assumptions about what the temperature of the Earth on average would be without any GHG’s. These assumptions are not really any more accurate than a Phil Jones, James Hansen, or Mike Mann calculation.
Unstated assumptions of the model here are that the Earth is a uniform sphere, that the short wave absorption spectra have little effect (it has a much larger effect than most people realize), and that winds distribute temperature evenly.
How about we do something in the physical sciences to measure the differences today in the atmosphere and the measurements that were taken half a century ago by the USAF in their upper atmospheric research program?
It is in the physical sciences where the answers to the effect of a modest increase in CO2 can be quantified, everything else is just arm waving. Chris is going to get trapped into fighting a battle on the enemy’s chosen field of battle, not where it should be fought, with measurements, with data, and with an understanding of the underlying physics involved.
“Monckton of Brenchley says:
December 29, 2011 at 2:50 am
CBA suggests one should take the temperature of the cloud tops into account when determining the characteristic-emission temperature. However, the characteristic-emission altitude is well above nearly all cloud tops, whose significant influence on the Earth’s albedo must nevertheless be taken into account”
Simply put, “characteristic-emission altitude” is nonphysical and is a meaningless concept. Cloud top emission of continuum along with surface continuum emission combined with some sort of measure of overall atmospheric absorption is about as simple as one can get before losing all concepts of the physics involved.
“Reed Coray says:
December 29, 2011 at 11:02 am”
Ghgs enter into the realm of things because 288k results in around 390 W/m^2 emission from the Earth’s surface. Since only about 239W/m^2 is absorbed from the Sun on average by the Earth system, there would be a serious imbalance if the Earth system radiated out 390W/m^2. That means there is 390-239 = 150 W/m^2 emitted by the surface that doesn’t make it out of the atmosphere. Calculations indicate that about 100 W/m^2 of this is due to GHGs like co2 and h2o vapor while the balance must be due to clouds and other non gas materials in the air.
A few further answers, particularly directed at those who seem to be trying needlessly to complicate a simple argument.
First, the characteristic-emission altitude is – by definition – that altitude, varying inversely with latitude, at which incoming and outgoing radiative fluxes balance. It is, therefore, a reality with a physical meaning, and asserting that it is not, as CBA tries to do, will not change the definition, or the reality.
Secondly, in Kiehl & Trenberth’s table 3, the 86-125 Watts per square meter that I have used in the calculations is stated to be the radiative forcing from the top five greenhouse gases – not, as Joel Shore ingeniously but disingenuously persists in trying to maintain, the forcing together with any consequent feedbacks. The warming of 33 K arises after nearly all feedbacks triggered by the base forcing of 86-125 Watts per square meter have operated, but is from the base forcing, not the forcing plus feedbacks, that the climate-sensitivity parameter and hence the climate sensitivity to the base forcing are determined.
Thirdly, Reed Coray wonders where the influence of greenhouse gases is to be found in the calculations that determine the Earth’s characteristic-emission temperature of about 255 K. Since the characteristic-emission temperature is invariant, it should be obvious that it does not change as greenhouse-gas concentration changes. The characteristic-emission altitude changes, but the characteristic-emission temperature does not, which is – of course – why there is no contribution of greenhouse forcings to its determination. The influence of 86-125 Watts per square meter of greenhouse gases is manifest in the 33 K difference between the characteristic-emission temperature of 255 K and today’s mean global surface temperature of 288 K.
Fourthly, I really should not have to repeat what I have plainly and often stated before: the characteristic-emission temperature is not – and is consciously not intended to be – a representation of what the actual surface temperature of the Earth would be in the absence of greenhouse gases. I have explained the basis and purpose of the three assumptions which lead to the value 255 K, and I have stated that that value is not, and is not intended to be, the actual surface temperature of the naked lithosphere in the absence of greenhouse gases.
Fifthly, the Earth’s bond or spherical albedo has been measured by numerous authorities, and is generally agreed to be 0.3, not 0.37 as one correspondent has tried to suggest.
Sixthly, the system-sensitivity calculation implicitly takes account of the fact that over the billions of years since the atmosphere first formed most temperature feedbacks will have operated. For powerful reasons, these feedbacks are far more likely to be net-zero or even net-negative than they are to be as strongly net-positive as the IPCC imagines. My calculations suggest that feedbacks are indeed net-zero or very close thereto. One should certainly not assume, as one correspondent has done, that merely because the water-vapor feedback is thought to be positive it actually is as strongly positive as the IPCC would have us believe, still less that because one feedback is positive the sum of all feedbacks must be net-positive.
To all correspondents who want to wander off into various byways, however engaging, I say “respicite finem”. Remember the purpose of these calculations, which is to gain some idea of the system sensitivity and the industrial-era sensitivity to a doubling of atmospheric CO2 concentration, based on the well-established scientific concepts and data that the IPCC itself and its supporters rely upon. It is easier to convince delegates at climate conferences that climate sensitivity may be low if one adopts as many as possible of the methods and parameter values that the IPCC uses. Whether those values are right or wrong, they are the values that the debate centers on, and if even with those values the climate sensitivity is low one does not need to complicate matters by arguing that climate sensitivity ought really to be still lower.
As best I can make it out, climate sensitivity is about one-third of the IPCC’s central estimate. The few trolls who are still trying to maintain that my argument is in some measure dishonest should understand that I have made every detail of the calculation plain, and whatever is plain – however disagreeable and inconvenient the trolls may find it – is likely to be honest.
Most of the correspondents who have thought they were questioning my calculations have in fact questioned the long-established climatological physics that I have used. In almost every instance, if they were right the climate sensitivity would be well below the already very low values I have demonstrated. And it is that low sensitivity – now increasingly supported by measurements published in the peer-reviewed literature – that is the main point. If I am right, it is unlikely that 21st-century warming will even reach the IPCC’s minimum projection of 2 K. Progress in the first one-ninth of this century: zero warming.
cba says: December 29, 2011 at 12:49 pm wrote:
“Calculations indicate that about 100 W/m^2 of this is due to GHGs like co2 and h2o vapor while the balance must be due to clouds and other non gas materials in the air.”
Calculations may indeed show what you claim, but Lord Monckton’s algorithm doesn’t. As I have said from the outset, greenhouse gases may in fact introduce a 33 K temperature difference, but Lord Monckton’s algorithm, which I believe is commonly used to justify the 33 K temperature difference, fails to make the case.
Monckton of Brenchley says:
The point is that the 86-125 W/m^2 that you quote includes the forcing due to water vapor. However, if water vapor is a feedback rather than a forcing, then it is not correct to account for its contribution the forcing. You have created the perfect circular argument: If one consider everything to be a feedback rather than a forcing, then the climate sensitivity that you derive will necessarily be the no-feedback sensitivity. I have explained it well with the analogy to the Bill Gates feedback. I suggest you read that and understand it rather than continuing to fool yourself and others here.
This divide it by four stuff for solar insolation is absolute rubbish. There is empirical evidence it is rubbish – the day temperature on the moon is not ~ 278 K or ~5 degrees C as predicted by this nonsense – it is over 381 K or 107 degrees C.
Why does everyone talk all this greenhouse nonsense ?
Doesn’t the majority of the atmosphere, Nitrogen and Oxygen, become heated by convection and contact with the warm surface of the Earth ? And like everything else they emit IR because their temperature is within the range where IR is the characteristic radiation ?
Doesn’t the temperature of the atmosphere explain downwelling longwave radiation ? If not – why not ?
If they do the radiation from IR absorbing gases – especially CO2 – is reduced to trace amounts. Even the concentrations of water vapour are trace.
Besides every gram of water vapour has absorbed enough energy – latent heat – to heat a gram of CO2 to ridiculous temperatures if the Engineering Toolbox tables of specific heat are right.
If the IR absorbing gases will heat the atmosphere theory is correct then I ask how ? They say Nitrogen and Oxygen are transparent to radiation so I guess they’re saying they don’t get hot.
Obviously 99% of the atmosphere becomes heated during the day and cools at night – what matters is the rate of cooling because as the temperature drops the Earth spins and the energy begins to flood in to your location next sunrise.
I’ve seen dissertations which claim a reverse greenhouse effect – higher concentrations of IR absorbing/emitting gases provides more heat transport mechanisms to release energy to space hence reduced warming.
I personally don’t think radiation has that much to do with energy transport in our atmosphere compared to convection.
I also find no anomaly in the “effective” temperature of the Earth at 254 K several kilometres in the air.
This is simply a construct of the geometry of the initial “radiative balance” equations – to balance incoming solar radiation of ~936 W/sq m over a disk 234 W/sq m is all that is needed to radiate over the surface of a sphere.
In fact the fact that Earth radiates 234 W/sq m over a sphere proves beyond doubt the incoming solar radiation over the disk CANNOT be a quarter of the solar constant unless there is another energy source somewhere. The Earth’s surface must acquire the energy from somewhere because it provides the energy that heats the atmosphere – anything else is “perpetual motion” type nonsense.
Lord Monkton, whilst I am not seeking to question one of my climate heroes, can you also apply your mathematics so eloquently expressed above to the case of, say, Venus ?
Lord Monkton, when I said “can you”, I of course meant “I would be grateful if you would”.
For it seems that there is now some fundamental difference in approach and theory about how an atmosphere insulates.
In the course of just 12 months I have moved from being an ignoramus tree hugger, to lukewarmer, to thinking that the effect of co2 upon Earth’s temperature is a big fat zero.
There are other things I find puzzling is the reinforcing effect claimed for the greenhouse effect.
The Earth’s surface is heated to the point where it emits some 390 W/sq m – more than the 168 W/sqm provided by solar power. This radiation presumably provides the bulk of the heating effect on the atmosphere which in turn provides 324 W/sq m “back radiation”. And everything nicely adds up.
If an object emits radiation does it not cool and enter a less energetic state ?
Surely this applies to both the Earth’s surface and the atmosphere. Each quantum of energy absorbed is lost in emission so the is no net energy increase in absorbing and emitting a quanta of energy unless you believe in perpetual energy.
I will continue to believe the Sun is the principal source of energy at the Earth’s surface and that climate “science” theories and scientists understate its effects by this factor of four nonsense.
If it is true – the factor of four thingie – it fails to explain daytime temperatures on the moon – or nightime ones as well.
If it is true – the factor of four thingie – why do the IPCC use this statement in AR4 –
“Between 1902 and 1957, Charles Abbot and a number of other scientists around the globe made thousands of measurements of TSI from mountain sites. Values ranged from 1,322 to 1,465 W m–2, which encompasses the current estimate of 1,365 W m–2.”
Shouldn’t they have measured something like 341 W/sq m ?
If the sun can heat the Earth’s surfaces and atmosphere to more than the minus 18 degrees C implied by the factor of four reduction in solar insolation there is no anomaly – the Earth heats up during the day, cools at night and because the rotation is a 24 hour cycle the heating beginas again.
As summer starts from a cool base day by day the heating increases until the onset of fall and winter again.
Our Sun is called a variable star so it can easily be responsible for slowly increasing temperatures over a couple of hundred years. What we need to fear is a reduction of incoming energy which history suggests will occur again.
Don’t forget that the Earth is a rather large heat source, too.
Internal temperatures increase with respect to increasing depth into the Earth’s interior. Away from tectonic plate boundaries, it is 22.1°C per km of depth (1°F per 70 feet of depth) in most of the world.
Rosco says:
We are not talking about daytime temperatures. We are talking about average temperatures. That is the relevant quantity for which one can apply total energy balance arguments. (Or, to be more accurate, what is constrained is the average of T^4 over the surface.)
To determine the full range of temperatures on a planet (or moon), one needs to work a lot harder, by considering various other means of transport and storage of thermal energy on the planet.
Monckton, this seems to be basically an expansion on your 2006 Daily Telegraph article: the main point being, that by THEIR OWN maths, IPCC’s sensitivity postulates are wrong.
Discovery of this article, Gavin Schmidt’s response to it (amplified by Monbiot), Monckton’s response to Schmidt, and Schmidt’s unmentioned but significant non-response to Monckton’s response, was a key find for me, proving (a) IPCC’s mendacity (yes, fraud); (b) Real Climate’s mendacity by omission; (c) the non-case for alarmism actually proved by the maths at the heart of the IPCC cyclone – if one knew how to look.
“Monckton of Brenchley
First, the characteristic-emission altitude is – by definition – that altitude, varying inversely with latitude, at which incoming and outgoing radiative fluxes balance. It is, therefore, a reality with a physical meaning, and asserting that it is not, as CBA tries to do, will not change the definition, or the reality.”
This is a variant to the Hansen 1993 National Geo. Research and Exploration paper where Hansen tries to make something of the altitude where the temperature is what is required for a blackbody continuum to match what is absorbed by the Earth system. He too assumes that the lapse rate will remain unchanged with added CO2.
The lapse rate exists because of conservation of energy and the transfer of energy in and out of each layer from all methods of heat transfer in and out define it. Changing the composition of the atmosphere with CO2 will affect the absorption rates, emission rates, convection rates, and conduction rates, and the mass of the layer. That would suggest that the lapse rate will change as the atmospheric composition changes.
While the definition may be solid, I don’t see this concept as meaningful – NOR necesssary to determine the warming due to the atmosphere’s presence with ghgs as being an average of 33 deg C above what the balance would be without an atmosphere. I also see Hansen’s effort as being just a red herring. Note that some of this warming is due to the presence of clouds, most is due to water vapor and a tiny fraction will be due to a co2 increase and a relatively small amount is due to the current level of co2.
@Bomber_the_Cat
“Geothermal heating, averaged over the surface of the Earth, amounts to about 0.08 Watt/m2 This is very small compared to the solar radiation absorbed into the Earth’s climate system ( 240 Watt/m2 ). In terms of climate therefore, geothermal heating can be considered to be insignificant.”
What I do not understand is how this tiny figure was determined (0.08Wm-2) and how on earth (no pun intended!) that can result in the high temperatures we see in bore holes and mine shafts. The most interesting question, and the one I think should be the starting point, is what would the surface temperature be as a result of only the earth’s internally generated heat in the absence of the incoming solar and the absence of the “blanket” of the atmosphere. Why is it hot in mine shafts and why is that real and sizeable heat ignored in all these clever thought experiments?
In my limited google survey I found that the guesses of the amount of heat and even what causes the heat are very immature. The raw value of the heat flux across the surface boundary ranges quite a bit with that 0.08Wm-2 being in the lower range. Some say the internal heat is residual heat from planetary formation, plus ongoing radiactive decay, plus losses in the earth’s electrical dynamo and then some even say that the ongoing gravitational effects of the moon and sun (and to a far lesser extent the gas giants) cause the hard inner core to wobble around in the viscous inner mantle generating significant frictional heat.
All of these effects are almost completely unquantified and I have failed to find a reasonable explanation of how the “average” flux of 0.08Wm-2 was determined. Anyone point me in the right direction please?
In addition to what has already been written about the differences between the earth and the moon, while the moon takes 27.32 days to rotate once, it is only 1/4 as large as the earth. So while the equator on earth moves at 1669 km/h, the equator on the moon moves at 16.7 km/h, or about 100 times slower. In physics, it is often very helpful to think of an extreme case to see what effect something may have on the surface temperatures. In this case, compare a moon spinning once per minute and a moon with one side permanently facing the sun. It is then obvious that the slower something rotates, the more extreme the temperature difference. And due to the T^4 rule, the more extreme the temperature difference, the more meaningless is an arithmetic average.
In addition to what has already been written about the differences between the earth and the moon, while the moon takes 27.32 days to rotate once, it is only 1/4 as large as the earth. So while the equator on earth moves at 1669 km/h, the equator on the moon moves at 16.7 km/h, or about 100 times slower. In physics, it is often very helpful to think of an extreme case to see what effect something may have on the surface temperatures. In this case, compare a moon spinning once per minute and a moon with one side permanently facing the sun. It is then obvious that the slower something rotates, the more extreme the temperature difference. And due to the T^4 rule, the more extreme the temperature difference, the more meaningless is an arithmetic average.
This is incorrect. The Apollo 15 and 17 temperature data tracks very well with the cosine angle with a preciptious drop at the terminator. The only thing that the slow rotational effect influences is the release of heat from the Moon that was gathered during the day.
We are not talking about daytime temperatures. We are talking about average temperatures. That is the relevant quantity for which one can apply total energy balance arguments. (Or, to be more accurate, what is constrained is the average of T^4 over the surface.)
This is what I don’t like about these kinds of calculations. For example CO2 has a temperature dependency to its absorption spectrum and this kind of calculation ignores variables like that.
I hate simplistic assumptions when we have the technology to obtain the real data.
To: Monckton of Brenchley
Christopher, following my remarks above at: December 29, 2011 at 12:20 am I wish to make an apology for previously not comprehending where you were coming from, and I think that others here are also mistaken and have wandered off-topic, interesting though much of it has been!
Put in a few words, it now seems to me that you have used a simple argument to show that the “consensus” treatment of global average temperatures and feedbacks and whatnot, do not really add-up to a good sensitivity assessment etc. I strongly think that it does not necessarily mean that you agree with say the Trenberth/IPCC stuff, and that you were trying to keep it simple in order to reveal issues within the current dogma. If you were to throw-in the complexities that have been raised here, (some of them I think to be valid in reality), your simple message may have become too complicated to follow for an “average audience”.
Damned if you do, and damned if you don’t!
Someone up above critiqued you for implying that lapse rate is unaffected by GHG’s, but without giving any substantiation. Well, I support you in that lapse rate must exist, with or without GHG’s, and it becomes speculative as to the importance of GHG’s as far as I’m aware. If we are to believe the latest Trenberth depiction, the relevant heat transfers (net thermal energy loss) from the Earth’s surface in W/m^2 are:
Thermals = 17, Evapotranspiration = 80, Surface radiation directly to space = 40, Surface radiation absorbed by atmosphere = 23.
Thus, the radiative heat transfer from the surface involving absorption by GHG’s is only about 14% of the total, according to Trenberth, whilst ignoring the mystery 0.9% of “missing heat”. Thus, it would seem to be difficult to demonstrate that GHG’s have a substantial effect on the lapse rate.
I believe the non-greenhouse, 255 degree K equivalent temperature that Lord Monckton mentioned is just a simplified artificial construct. The problem I see here is that too many people are taking this to be a supposedly accurate prediction of the absolute temperature of the Earth. It is no such thing. As radiant energy flow is proportional to the fourth power of the *absolute* temperature, this value is, in effect, a very special average: It is equivalent to the fourth root of the global average of the fourth powers of absolute surface temperatures over the entire surface of the Earth. I believe this also assumes a constant global surface albedo, but that does not need to be the case.
Christopher;
You say, “Robert of Ottawa asks what the surface temperature of the Earth with an all-nitrogen atmosphere would be. In the absence of any greenhouse gases, the answer is 255 K or thereby.”
I think here we have a crux issue to test (or examine) the ‘Unified Theory’ hypothesis, because as I understand it, only the mass of the atmospheric overburden matters, so assuming the same mass, their answer would be 288 (surface, where the weight and pressure are at maximum, not at TOA, or even “characteristic emission level” necessarily). Only mass changes affect temps in their system.
Rosco,
The factor of 4 nonsense is geometry, not science. The amount of solar power hitting Earth amounts to the equivalent of a disk with Earth’s radius. That is spread over a hemisphere (half a sphere) since the Earth is essentially a sphere. The other half of the sphere at any one time is in total darkness. However, for the emission of power radiating from the Earth, it is happening all of the time over all of the Earth. Surface area of a disk = Pi* R^2. Surface area of a sphere = 4 * Pi * R^2. Since one is trying to compare what is radiated out from the Earth to the total incoming solar power, it is necessary to use averages for solar power since it varies from the 1362 W/m^2 at high noon to effectively nothing at midnight (assuming we’re talking about the equator and not the arctic circle region). Note that even this 1362 W/m^2 is an averaged value because Earth’s orbit is not a circle but is an ellipse which places us nearer and further away from the Sun at different times of year. Right now, we’re about as close as we get to the Sun and the incoming power is going to be more like 1400 W/m^2 at present. Around July, we’ll be furtherest away from the Sun in Earth’s orbit and the solar power there will be around 1320 W/m^2. As a quick reminder, seasons are due to Earth’s tilt, not orbital distance to the Sun and despite the Earth receiving more power in our winter and less power in our summer in the northern hemisphere, it tends to get hotter and colder here than in the southern hemisphere – and that is substantially due to the Pacific ocean covering a substantial portion of the southern hemisphere while most of the land mass is located in the northern.
Oh well, lets see if Monckton can work this up to a full paper, and if a reputable journal will publish it. Somehow I doubt it.
Talking about warming caused by industrial era CO2, and warming since 1750, is incorrect (of the IPCC). The industrial era, when mankind may have made more CO2 started in 1950, not 1750. Therefore, only the warming from 1950 to today need be taken into account. Otherwise, one must show that in the 200 years from 1750 to 1950, mankind made a lot of CO2, can this be shown? If not, than the warming is said to only be 0.3C from industial era man made CO2, according to the IPCC, hence, the sensitivitie is even lower, about half of what they claim. We know that it warmed some 2C or so since 1750, and that most of this warming happned prior to 1950 (actually, prior to 1850), thus we see that a LOT of warming happened prior to any industrial era CO2.if we subtract the warming from 1750 to 1950, how much warming is left over? Answer, at least 1.7C, which dwarfs the paltry 0.3 the IPCC claims. The natrual warming is thus seen to be greater than 5 times the industrial era warming, which puts things in perspective.
Second, it definatly warmed from 1750 to about 1850, what caused that warming? Since it was not industrial CO2, it must be natural. If we do not know what it was, then we cannot be said to understand the climate well enough to seperate out the natural warming from the anthropogenic. Also, we know that warming includes the ocean, and that a warming ocean outgasses CO2, so how do we know how much increase in CO2 is caused by a warmer ocean as compared to industry?
Once again, I realise that you arwe simply showing that even the IPCC’s own figures show them wrong, yet I hope I have shown that it can easily be shown that even these figures can easily be shown to be, frankly, impossible. If they continute to use the 1750 date, they prove by that date that they cannot be right, simply by including that date. Keep bringing up the contrat between the dates 1750 and 1950, when industry really got rolling, and you can show that the IPCC is not being honest in their use of 1750. Basically, you want anyone who believes in the IPCC to wince whenever they hear the date 1750.
http://apod.nasa.gov/apod/ap970110.html
Here’s a nice IR photo of the moon during a lunar eclipse that shows that without atmosphere the moon’s surface does not heat uniformly – nor I suppose hold heat uniformly. I am guessing that both variable albedo and variable emissivity of surface rock are at play in making the moon look like a speckled, imperfect blackbody radiator.
Respice Finem? I think “Bring knowledge to life” is a better motto for any blog.