Guest essay by Robin Pittwood, Kiwi Thinker
Abstract
The core of the human caused global warming proposition is that an increasing level of greenhouse gases acts to reduce heat loss from the planet making the atmosphere here warmer. The amount of warming anticipated by the IPCC models is from about one to several degrees C for a doubling of CO2 concentration. But a conundrum has arisen lately: While CO2 has continued rise significantly the temperature has not. There has been no global warming since about 1997. Scientists on both sides of the debate have noticed this and have offered something like 55 explanations as to why this could be so. Some of those explanations lock into the dogma built into the IPCC models, taking for certain that the greenhouse effect is increasing, but because there is no atmospheric temperature rise, they then have to explain the retained heat is somewhere else.
But is the greenhouse effect occurring as the IPCC models propose?
This study analysed two important factors directly associated with the greenhouse effect; atmospheric temperature and outgoing radiation, and finds that outgoing radiation has not declined. The missing heat has gone back to space as usual. But more importantly the (lack of a) trend observed in an empirical derivation of the Stefan Boltzmann relative emissivity factor directly contradicts the greenhouse theory built into the IPCC models.
Article
Regular readers at any of the main climate change blogs will be aware that since about 1997 there has been nearly no global temperature rise. And they will know too, that this is despite atmospheric CO2 concentration continuing to rise. To date there are some 55 ideas to explain this slowdown in global warming. Some of the ‘explanations’ presume the so-called ‘greenhouse effect’ must still be increasing as the IPCC models calculate; it’s just that the heat has hidden elsewhere, maybe deep in the ocean.
This study, based on 34 years of satellite data; outgoing longwave infrared radiation (OLWIR) and temperature, demonstrates otherwise.
I used three data sets, OLWIR from NOAA, and the average of both UAH and RSS for global temperature.
I obtained monthly average OLWIR (W/m2) for each 2.5 degree latitude by 2.5 degree longitude area of the globe. After converting the netCDF files to Excel, I scaled each 2.5*2.5 area’s OLWIR to account for the varying size of its area, resulting in a global average OLWIR. (There was some missing data mid 1994 to early 1995. I populated this by a linear interpolation). The resulting annual average OLWIR is shown in the graph below for the years 1979 to 2012. While there is some variation, OLWIR has generally increased over the period, maximising lately at around 233 W/m2.
The temperature data is also plotted on the graph below.
It is noted that while there is some variation, temperature also has generally increased over the period, maximising lately at around 0.2 oC.
The relationship between temperature and emitted radiation should follow a universal law of physics. Stefan Boltzmann’s law states the emitted radiation is the product of the fourth power of absolute temperature and an emissivity factor. A reduction in the emissivity factor means less outgoing radiation for a given temperature, and that would indicate a stronger greenhouse effect. An increase in the emissivity factor means more outgoing radiation for a given temperature, and that would indicate a more transparent atmosphere. The study derived earth’s emissivity factor for each of the 34 years and the results displayed.
Using an average global temperature of 287 Kelvin added to the temperature anomaly, the relative emissivity has been derived for each year using the formula:
RE = j / (k*T^4)
where RE is the relative emissivity, j is OLWIR, k is the Stefan Boltzmann constant, and T is the temperature.
If the greenhouse effect was increasing, relative emissivity should be declining. A quick look at the graphs shows clearly this is not the case. Our planet’s relative emissivity has been flat-lining, despite increasing CO2 concentration over the study period. The derived emissivity factor, being basically constant, directly contradicts all of the IPCC models. No increased greenhouse effect is observed.
Findings:
The two primary findings of this empirical study are:
· Outgoing radiation has not declined over this period as expected by IPCC models. In fact it has increased. The missing heat has gone back to space – as usual and in the quantity as per Stefan Boltzmann’s law, via OLWIR, and
· The increasing greenhouse effect expected by IPCC models, is not evident in the measurements. It appears there has been no increased greenhouse effect over this period. [A closer inspection of the relative emissivity trend shows the atmosphere is even becoming a little more transparent – though little should be made of this given the variability of the data] and the scale.]
Conclusion:
The core of the human caused global warming proposition is that an increasing level of greenhouse gases acts to reduce heat loss from the planet making the atmosphere here warmer. But is the greenhouse effect occurring as the IPCC models propose? This study analysed two important factors directly associated with the greenhouse effect, atmospheric temperature and outgoing radiation, and finds that the trends observed, along with an empirical derivation of the Stefan Boltzmann relative emissivity factor directly contradicts the greenhouse theory built into the IPCC models.
The original post on this study may be found here.
Robin is confusing emissivity with the greenhouse effect. Emissivity isn’t power (W/m2); it is a dimensionless ratio. Dimensionless ratios don’t warm anything; energy (power*time) does. So Robin’s analysis of emissivity can’t tell us anything about the GHE or AGW! Greenhouse gases slow down the rate at which radiation (energy) emitted by the surface escapes to space. For this reason, climate scientists sometime define the greenhouse effect (G) using the following equation:
OLR = oT^4 – G
where OLR is infrared radiation escaping to space, o is the S-B constant, and T is surface temperature. All three terms in this equation involve energy (per area per time), not dimensionless ratios. If Robin had used this equation, he might have presented something useful about the GHE.
QUESTION: Why isn’t OLR decreasing as GHG’s have been increasing? ANSWER: T may have gone up enough to compensate since 1979 – leaving OLR unchanged.
QUESTION: If OLR didn’t drop between 1979 and 1997, why did temperature rise during this period? ANSWER: Warming isn’t caused by a DROP in OLR; it is caused by a CONTINUING radiative imbalance (SWR – TOA OLR). A radiative imbalance grew during the first half of the 20th century and then probably remained approximately constant as the earth began to warm as heat from the imbalance accumulated.
QUESTION: Why hasn’t temperature gone up since 1997? Unforced variability can be high. If surface temperature can go up 0.5 degC in 1997 and down 0.5 degC in 1998, we can’t draw ANY unambiguous conclusions about the greenhouse effect from the absence of the smaller SURFACE warming (0.15-0.2 degC/decade) expected during the hiatus. ARGO has shown that the ocean – unlike the surface and troposphere – has warmed at a steady rate appropriate for a radiative imbalance of about 0.5 W/m2 for the last decade. This ocean warming is evidence that the greenhouse effect has been operating during the hiatus. The energy associated with ocean warming is much larger than the energy missing from surface warming.
What happened in ’97-’98? Upwelling of cold deep water in the eastern equatorial Pacific and downwelling of warm water in the western equatorial Pacific both slowed. The resulting warmer Pacific warmed the rest of the surface and troposphere. When normal rates of upwelling and downwelling were re-established, the temperature returned to “normal”. It is POSSIBLE that after the 97-98 El Nino, upwelling and downwelling may have been greater than before – carrying Trenberth’s “missing heat” into the deeper ocean. Unfortunately, ARGO isn’t sensitive enough to detect this “missing surface heat” in 2000 m of ocean. Multi-decadal patterns such as the AMO and PDO may be associated with differences in upwelling and downwelling.
FINAL QUESTION: Is the IPCC right after all? ANSWER: Of course not! The IPCC’s climate models over-predicted the amount of warming and under-predicted variation in warming rate. Their estimate of aerosol cooling appear to be too big; making the over-warming problem more serious. Their future projections are therefore dubious at best. The IPCC discounted the importance of unforced variability (such as the 1925-1945 warming), so that they could over-interpret the similar 1978-1998 warming. They incorrectly attributed all of the 1960’s hiatus to aerosols, opening the door for the current hiatus (which is similar so far) to really damage their credibility. However, ARGO shows that the current hiatus in surface warming hasn’t disproved the greenhouse effect.
He calculated a dimensionless ratio (the RE) and, broadly speaking, he is correct that this ratio should reduce as the GHE increases. He, effectively, calculates RE thus
RE = OLR/ Surf_Rad
If the enhanced GHE causes the Surface Temperature to rise then the Surf_Rad increases and RE reduces. If the enhanced GHE results in no rise in surface temperature (e.g. there is a pause) then OLR should fall and, again, RE reduces.
John Finn: Climate scientists sometimes define the greenhouse effect (G) to be the amount of radiation (heat) that does not make it through the atmosphere. (Other times they calculate 33 degC of warming.)
G = oT^4 – OLR_TOA
Doing some algebra gives:
emissivity (e) = OLR/oT^4 = 1 – G/oT^4
In other words, the emissivity of the atmosphere is not determined by G alone and vice versa. If both G and oT4 increase at the same rate, the greenhouse effect can strengthen without ANY CHANGE in emissivity.
Rearranging the terms differently:
G = oT^4 * (1 – e)
G can go up if oT^4 increases (the surface warms) or if emissivity gets smaller or some combination of both occur.
Rearranging the terms one more time:
OLR = oT^4 – G
Warming is caused by a radiative imbalance:
imbalance = post-albedo SWR minus OLR at TOA.
When increasing GHGs increase the G term, OLR goes down and the earth begins to warm. That makes the oT^4 term begin to increase and radiative balance begin to be restored. The IPCC tells us that aGHG’s have increased G about 3 W/m2 since 1750. The rate of ocean warming measured by ARGO tells us that the CURRENT imbalance is only about 0.5 W/m2. 0.7 degC of surface warming would account for the other 2.5 W/m2.
Use the right equation; get the right answers.
davidmhoffer November 9, 2014 at 1:24 am
“The increased heat capacity in the atmosphere would be predicated upon the amount of heat trapped by the increased number of CO2 molecules. At a concentration of just 280 ppm (pre-industrial) and doubling them to 560 ppm , we’re still talking about a tiny, Tiny, TINY percentage of the molecules in the atmosphere with a heat capacity that is miniscule and may as well be considered zero. That’s why I get all bent out of shape when the MSM yammers on about heat trapping gas. Technically true but at a value so small it may as well be rounded off to zero.”
CO2 has a lower specific heat capacity than O2 and N2.
http://www.engineeringtoolbox.com/specific-heat-capacity-gases-d_159.html
The specific heat of air should decrease with added CO2.
CO2 has a lower specific heat capacity than O2 and N2.
Sure. But they have different absorption spectra:
http://upload.wikimedia.org/wikipedia/commons/7/7c/Atmospheric_Transmission.png
(sorry, don’t have a link that includes N2, but this give you the idea)
So CO2 temporarily captures photons and their associated energy in a frequency band that literally sees O2 and N2 as “invisible”.
davidmhoffer November 9, 2014 at 9:37 am
‘So CO2 temporarily captures photons and their associated energy in a frequency band that literally sees O2 and N2 as “invisible”.”
David,
without thermalisation, you have captured nothing, temporarily or otherwise. The best you can achieve without thermalisation is instant absorption and re-emission at light speed, like scattering or reflection.
If you believe that 15µm radiation can be thermalised anywhere in the troposphere you may want to check that: http://www.calctool.org/CALC/phys/p_thermo/wien
The effectiveness of the GHG effect must depend on the probability of the excited molecule emitting a photon before transferring the kinetic energy to other atmospheric gases. Trace gases like CO2 must have a very low chance of warming the surface.
The chance of radiating a photon increases with the concentration of GHG since the potential to radiate can be retained if collision is with a GHG of the same type. A trace gas like CO2 is never going to make much difference.
Water, on the other hand, is not only present in our atmosphere in much higher concentrations, but in clouds the concentration is massive, guaranteeing that downwards radiation has a noticeable effect.
This is why cloud coverage retains heat at night, the GHG effect is lacking in the desert and trace GHG has virtually no effect.
@joel O’Bryan
My Climate mea culpa came 12 months (or so) ago.
I am a PhD scientist (not a physicist, but a BS CE and a PhD in Bio-med, and 4 years of ME EE work), and I KNOW this one thing………………..
An entire Climate Science Mea culpa for Climate Change protagonists is coming.
Alas, Dr Joel, you may be well versed in Bio-Medics and Engineering, but you seem less competent in Sociology and Socio-Psychology.
Though it is common for the ‘hard’ sciences to sneer at the soft ones, and in many cases this is justified, there are still some truths and understanding to be cleaned from a study of human social interaction en mass. Charles Mackay’s “Madness of Crowds” is a good example.
The scientific establishment has been wrong many times before. As, indeed, have most established sectors of humanity – the military, the politicians, etc… Each time they pick themselves up and go on as if nothing had happened, joining in an unspoken conspiracy not to mention the error again. Anyone who draws attention to the mass delusion that made sane humans think that marching troops forward into machine guns is a good way to win a war, that appeasing a dictator would ensure peace, or that a tea-stained mix of human and orangutan skulls proved that early man developed brains first is at first politely ignored, then thrown out of the club if they persist in pointing out the lack of clothes on the Emperor…
In this case we will probably stick with the belief – too many people have built careers on it. Only when they have gone will a new tranche of climate researchers be permitted to say what is currently not able to be uttered if you want to keep a job in climate science.
Hmm…All IS vanity… Oh, sorry,went to parochial school.
Sadly, I’m afraid your socio-psychological analysis is absolutely right…
But maybe mother nature might help quickening the acceptance of the “aha-effect” by some cooling in the next decades…
It doesn’t really make any real difference, but my understanding was that CO2/GHGs don’t reduce the heat leaving the earth, but trap more in the atmosphere than the atmosphere could move into space. Disrupting the balance. And the hiatus heat can’t be on the deep ocean because heat won’t flow in that direction. Bottom line is that CO2/GHGs simply don’t have the horsepower to overcome all the other factors, i.e. ocean evaporation, clouds, precipitation, solar thermal heating, etc. in the earth’s natural heat flow/balance.
IPCC AR5 TS.6 Key Uncertainties is where climate science “experts” admit what they don’t know about some really important stuff. They are uncertain about the connection between climate change and extreme weather especially drought. Like the 3” drought that hit Phoenix. They are uncertain about how the ice caps and sheets behave. Instead of gone missing they are bigger than ever. They are uncertain about heating in the ocean below 2,000 meters which is 50% of it, but they “wag” that’s where the missing heat of the AGW hiatus went, maybe. They are uncertain about the magnitude of the CO2 feedback loop, which is not surprising since after 18 plus years of rising CO2 and no rising temperatures it’s pretty clear whatever the magnitude, CO2 makes no difference.
http://www.writerbeat.com/articles/3713-CO2-Feedback-Loop
I recently read an article by Hansen et al 2013 on Assessing Dangerous climate change (I’m not all the way through it yet!) and it is pertinent to this argument to take values from its very first set of graphs (less easy for CAGW believers to dispute) that show total fossil fuel CO2 emissions have gone from @ur momisugly1.5GT/pa in 1950 to @ur momisugly10GT/pa now a six or even sevenfold incease and yet the only other pertinent quantifiable measure – the Mauna Loa CO2 record – shows an increase from @ur momisugly 1.5 ppm to at best 3ppm now.
If the global warming camp is to be believed then surely this ppm reading should have increased by the same amount and should be at least 9ppm now as both amounts are factual and entirely quantifiable.
By their own readings therefore there must be (and I mean MUST BE) a negative feedback of 6ppm as compared with the 1950s. Where has this gone. Forget the heat hiding! an average of 4GTpa since the 1950s has just disappeared, some 250GT – I dont recall anybody ever noticing that. Perhaps that too has hidden in the oceans……..oh but wait that would mean that Global warming cant be happening at the expected rate – thats not right…….or perhaps this ‘pocket’ of CO2 will suddenly reappear in some monstrous upwelling and asphyxiate us all!!
Actually I reckon it is in the oceans mostly – due to a biological negative feedback response – but thats a personal opinion. But where else has it gone!
Have you forgotten the biosphere?
mwh- all apologies… I did not read your second response, wherein you spoke of the biosphere.
Good point. The reason is that there are carbon sinks. One is physical,,the oceas vianHenry’s Law and Le Chatellier’s principal. The other is biological, evidenced by the greening of the Sahel (as more CO2 enhances C3 photosynthesis) and the white cliffs of Dover (ocean sequestation as planktonic (diatoms, coccolythophorids) calcium carbonate ‘shell’). All limestone deposits evidence biologically sequestered CO2. It is presently thought that the biological sink is roughly 50% terrestrial and 50% oceanic. See the climate chapter in The Arts of Truth ebook.
It is obvious that neither the physical nor the biological sinks are saturated, nor can be given Earths history. So the net atmospheric residual is much less than emissions. Keelings curve gives some sense of the met present carbon sink imbalance.
Your figures seems not completely right, as since 1960, when the accurate measurements at the South Pole and Mauna Loa started, all players: human emissions, increase in the atmosphere and net sink rate increased a 4-fold. The ratio between increase in the atmosphere and human emissions remained quite constant over the past half century:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1960_cur.jpg
For the current 4.5 ppmv released by humans, some 2.25 ppmv remains in the atmosphere, 0.5 ppmv is absorbed by vegetation, about 0.25 ppmv by the ocean surface layer (the upper few hundred meters) and the rest of the difference, some 1.5 ppmv got into the deep oceans. All in mass amounts, not the original emitted molecules…
This was an over simplification that did not include possible change in albedo (from clouds, or changes in large scale organic sources from CO2 increase). Mixing albedo change with emissivity is not valid.
But…….even with all the caveats, this appears to work better than the repeatedly readjusted computer models. Now ain’t that strange…….
The “emissivity” as calculated here should not be confused with a true emissivity as defined in the context of the Stefan-Boltzmann law. Instead, it is a relative measure of the resistance put up by the whole atmosphere, with greenhouse gases, clouds, convection, and all, to the transport out to space of IR that is emitted at the ground level. While this parameter should probably have been named differently in order to avoid confusion, it would seem that it should indeed change in response to a significant, uncompensated increase in the greenhouse effect.
It is of course a very crude approximation to treat the entire earth as a single emitting body with homogeneous temperature. However, most of this crudeness should cancel out when pseudo-“emissivity” is compared between different time points.
Very good post, lots of clueless comments about basic physics. Just to take one, Nick Stokes wrote:
” The earth is not a black body. The outgoing spectrum has a very big dip in the CO2 absorption region. This reflects that the emission there is from high altitude. So there is no constant (over frequency) emissivity factor. This matters.”
The author treated emissivity as a variable, why the straw man about a black body? That is just poor. What CO2 absorption “region”? CO2 absorbs at specific frequencies, and those frequencies were saturated at pre-industrial levels. That has nothing to do with the altitude, you haven’t the slightest idea what you are talking about. The author did not say there was constant emissivity, either, that is two pathetic straw men in one post.
Yes, Mr. Stokes often resorts to straw-men in defense of his religious beliefs.
“The author treated emissivity as a variable”
I said, constant over frequency. He is assigning a single number emissivity which varies over time.
It matters because most of the GHE involves that variation within the frequency spectrum. The GHG bite becomes deeper, because that part of emission is from higher altitude. But solar incoming still has to be emitted, so other parts of the spectrum have to emit more. These come from lower altitudes; with the atmospheric window, it comes from the surface. To emit more, emitting regions have to become warmer.
You can’t get any of this with a black body spectrum.
Nick is again, correct. If we’re going to be skeptics, let’s be skeptics on the basis of the correct science.
OLR at TOA is a net of everything. GHG scattering, water vapor feedback, clouds, aerosols,… So there is no direct connection to SB. And SB cannot be used in the pure simple form here because Earth is a grey body, which among things says the SB approimation cannot be applied to global average temperature, at best only to zonal latitude averages by season. Which is how the rigourous 1.0C per doubling of SB becomes 1.2C in grey Earth approximations accepted by Lindzen as starting points for his analyses.
Thanks for this. Real data, real science and a real explanation of our world’s temperature regulation mechanisms.
I have long suspected that if CO2 is effective at increasing energy absorption it would also increase emissivity. This does not exactly prove it but sure indicates some connection. As is mostly the case a new answer raises new questions but this is progress toward understanding the mechanisms of climate and “Greenhouse Gases”.
Let us search and research for facts before we leap to conclusions. Saves money, effort and embarrassment.
Apart from Nick’s points, another severe problem with the analysis is that even if the S-B law is valid in this situation, it says the OLR is proportional to the fourth power of the temperature. That means if you are doing any averaging then you must take the instantaneous temperatures to the fourth power before averaging them to compare them with the average OLR. The one thing you cannot do is to average the temperatures and then take the fourth power, because you have lost a huge amount of relevant information by doing this.
The reason for this is explained below.
Take two days of the same average temperature, averaged over the normal 24 hours of midnight to midnight. Assume the temperatures during both days are sinusoidal. The averaging method used in this post would say the OLR from both days was the same.
But what if one day had twice the range of the other (both have the same average remember) – say it was 20 degree peak to trough instead of 10 degrees about an average of say 300K (27 C). The fourth power of the S-B law will emphasise the peak temperatures of any day and de-emphasise the troughs in the OLR average for the day. So the first day should have a significantly higher OLR than the second day, but the calculation in this article assumes they are the same which is false.
When Kiwi thinker went half way and worked out the effect of average monthly temperatures then the emissivity oscillated by month with a peak to trough of 0.024. There was no easy way to do it by day, but doing this will produce daily oscillations of a similar magnitude superimposed on top of the monthly oscillations in emissivity. So the peak to trough emissivities which he is averaging over a year will be around 0.048.
Bear in mind that the change in emissivity you are looking for to prove or disprove AGW is of the order of a reduction of 0.003, and you have oscillations of 0.048 – sixteen times as much. The standard error for the trend on a straight linear regression analysis is based on the standard deviation of the individual values about the calculated regression line, and it is fairly clear that with daily variation figures this is going to give you a trend standard error much higher than 0.003.
There may be sophisticated techniques available which give a reduced value of the standard error in the trend.
Of course all this is really just saying that you should not use the straight averaging of temperatures over individual years when trying to evaluate whether emissivity figures based on OLR prove or disprove the standard IPCC AGW projections.
Dodgy Geezer said “I wish someone with more intellectual capability/specialist expertise/time on their hands than I would look closely at the tropospheric hot-spot (or lack thereof)” I think you should read the debate at the American Physical Society in January this year. http://www.aps.org/policy/statements/upload/climate-seminar-transcript.pdf . Ban Santer’s comments were rather apposite; Lindzen’s rather pointed.
The answer is simple, people, just call it DARK HEAT like the astronomers do with matter & energy, although thermodynamics was there first with “entropy” which is the gap between observed heat and modelled heat. Maybe dark heat is just entropy in a different guise.
On the apparent use by Trenberth and IPCC of Stefan Boltzmann (SB) with emissivity = 1 for Earth surface.
Kiel and Trenberth, 1997; IPCC AR4 WG1, 2007:
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/fig/faq-1-1-figure-1-l.png
Surface Temperature ST from SB:
Surface Radiation (SR) = 390 [W/m2] = 5.67*10^-8 * ST^4
ST = 288.0 K = 15 Celsius
Trenberth et al, 2009:
http://www.cgd.ucar.edu/cas/Topics/Fig1_GheatMap.png
ST = (396/5.67 * 10^8)^-4 = 289.1 K = 16 C
The alleged energy imbalance in the latter cartoon amounts 0.9 W/m2 which is small relative to the Outgoing Longwave Radiation (OLR) of 238.5 W/m2. OLR/SR (the author’s “emissivity”) amounts ~0.602 in both cartoons, and less than 0.605 if the imbalance would be added to OLR in the second one.
The biggest unknowns in the energy budget are most likely the thermal and latent heat fluxes. Evapotranspiration (latent heat) is found to vary 6 percent per degree Celsius (K) of ST, based on satellite estimates; see Wentz et al, 2007 as referenced by Kininmonth, 2010 (p. 76 of pdf, p. 234 of E&E issue):
http://www.eike-klima-energie.eu/uploads/media/EE_21-4_paradigm_shift_output_limited_3_Mb.pdf
6 percent of 78 W/m2 – the latent heat in the 1st cartoon – amounts 4.7 W/m2, not the 2 W/m2 difference with the 2nd cartoon. This alone outweighs the presumed imbalance by a factor 3. As such, response of evapotranspiration to surface temperature delivers a much larger negative feedback than assumed by the IPCC in Global Circulation Models (GCM’s). This results in a climate sensitivity of less than 1 degree C, based on otherwise similar assumptions such as constant relative humidity with atmospheric temperature rise (see Kininmonth, referenced above).
“Ferdinand Engelbeen November 9, 2014 at 1:54 am
I have already problems with the first sentence:
The core of the human caused global warming proposition is that an increasing level of greenhouse gases acts to reduce heat loss from the planet”
#########################
when they get the theory wrong in the first sentence that is a good clue that more rubbish will follow
Atmospheric carbon dioxide, excited by IR radiation from the warm earth, is much more likely to pass on its excess energy as kinetic energy to non GHG molecules than to emit an IR photon in a random direction. In other words, the GHG is much more likely to promote convection than to radiate IR energy back to the earth. The reason for this is that the rate of photon emission is very slow compared with the rate of probable collision with other atmospheric molecules.
The real back radiator is clouds. The water in the clouds absorb the IR from the earth and radiates it in all directions as any warmed body will so do. Given the huge water content of clouds, this is a significant effect. Each water droplet is associated with water vapour saturated air, so this provides a huge localised mass of greenhouse gas capable of absorbing and re-emitting IR photons of the appropriate wavelength. These molecules also collide with their neighbours but in this case a very high proportion of the adjacent molecules are also water vapour so the excess kinetic energy can still be converted to IR radiation.
All of this suggests to me that clouds are the major source of back heating by IR radiation by a combination of general radiative warming and GHG warming. I am suggesting that this is the major source of back heating. I am also suggesting that lone molecules of GHG have little chance of avoiding collisions long enough to emit their energy as photons. The chances of passing their excess energy to another GHG molecule of the same type are very low for water vapour and tiny for a trace gas.
If the dominant GHG radiation is from clouds then one can understand why there can be no catastrophic positive feedback since clouds also act as earth’s sunshade by controlling incoming solar radiation. There is stability and elegant simplicity.
The magnitude of the GHG effect is based on a comparison of observed temperature compared with implied S-B temperature at equilibrium with solar radiation. This is not affected by whether the GHG radiation is from clouds or lone molecules. The radiative properties of GH gases are not in question. It is just that in the real world, many collisions with non-greenhouse gases are much more like likely in the time it takes to emit that photon.
The chances on average of a CO2 molecule hitting another GHG molecule of course depend upon where in the atmosphere the carbon dioxide is located. As you note, in a cloud there are a lot more H2O molecules than on average. But looked at on a larger scale, an exited CO2 molecule is on the order of 1000 times more likely to hit an H2O molecule in the moist tropics than the dry air above the poles.
If the global average of water vapor be around 30,000 ppm & other GHGs be considered too rare for inclusion, then the odds of a CO2 molecule bumping into a fellow GHG water molecule are one in 33, but of an inert argon atom one in 108, of an effectively non-GHG oxygen molecule 21% & non-GHG nitrogen molecule 78%. So a long shot, indeed.
Heat transfer in the system ‘the Earth’s surface – the atmosphere – open space’ is multimodal. It cannot be solved by handwaving about ‘radiative balance’.
http://pmm.nasa.gov/education/sites/default/files/article_images/components2.gif
A very useful concept of electrical cicuit analogy and thermal resistances can be used for analysis and solution. This is the circuit model with some assumption and simplifications:
http://file.scirp.org/Html/3-9801007/2786aedf-f5fe-470c-8af9-4710598bf569.jpg
And the paper:
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=1539#.VF_Hnsk4QxE
From the conclusions:
“The decreasing of the cover (atmospheric) temperature causes the decreasing of the core (surface) temperature. Anti-greenhouse effect realizes on this way, and the decreasing of atmospheric transmission causes global cooling. It is found as the additional result that the radiative heat transfer qr has small influence on the integral heat balance.
Greenhouse effect in it traditional interpretation real-izes when one of the following conditions is satisfied: qs > 50 W/m2; εs > εa; γ < 0.4.
It is found that trends of the climate change caused by the increasing of the carbon dioxide emission depends on the whole set of parameters realized actually nowadays. There is the great interest to determine the values of the parameters as reliably and quickly as possible. Small changes of the basic parameter values established after 12 years [7] don’t influence on our results."
So, increasing atmospheric CO2 cools the atmosphere and therefore the Earth's surface, just as some of us skeptics suggested. However, it's very likely insignificant.
Inasmuch as the premises of the simplistic “radiative greenhouse” paradigm have been drilled into the minds of true believers and skeptics alike, getting people to recognize how heat transfer, which indeed is multi-modal, actually operates in the climate system is a real challenge. Good luck!
While I applaud the effort, I find the results of the analysis quite puzzling. Several issues.
First, the author says that the average outgoing longwave infrared (OLWIR) is on the order of 230 W/m2 … but every other estimate I’ve ever read is on the order of 240 W/ms. This includes the CERES data, the Kiehl/Trenberth energy budget, and many more. At a minimum, the author needs to explain this huge 10 W/m2 discrepancy.
Second, the annual variation in the author’s OLWIR is much larger than that of the CERES data. The CERES data varies from 2000 to 2012 by only three quarters of a watt per square metre (0.75 W/m2), where the author’s values for that period vary by four W/m2, a huge disparity … again, this requires explanation.
Third, the author seems to think that if the greenhouse effect is actually working, that the OLWIR should decrease. I don’t understand this claim at all. Why should the outgoing longwave infrared decrease? The OLWIR is a function of the the downwelling shortwave radiation and the (largely oceanic) planetary heat storage. This is because output = input ± storage. So I don’t understand the author’s basic underlying claim.
Finally, the CERES data allows us to see the change in the greenhouse effect, which as the author points out can be measured as the amount of energy leaving the TOA divided by the energy radiated by the surface. But the problem, both in the author’s data and in the CERES data, is the size of the variation.
In the author’s data above, the ratio varies by about ± 0.5% (half a percent). In the CERES data it’s even smaller, at ± 0.1%. The author hasn’t given us any error bars for his results … but the 95% CI for the annual CERES results is ± 0.5%. As a result, we can’t conclude anything from the CERES-reported changes in the GHE, they are smaller than the error … and I would be shocked if the 95% CI in the data used by the author is smaller than that.
I’m sorry, but I find this analysis confusing, inadequately documented, without error bars, and lacking both data as used and code as used …
w.
I’m not sure he is saying this, Willis. I could be completely wrong and it may be me that’s missing the point but I think people are being a little over-analytical here.
If GHGs are increasing in the atmosphere 3 possible things will happen
1. OLR will reduce – only
2. Surface Temperature (and thus upward surface radiation) will increase – only. [see below]
3. OLR will reduce and Surface Temperature will increase.
Robin Pittwood is calculating the Relative Emissivity (RE) which he defines as the ratio of OLR (Y) to Surface Flux (X). So that
RE = Y/X
Clearly, then, as GHGs increase then RE will decrease. Robin’s analysis, though, suggests that RE is remaining constant and may even be increasing. He has, therefore, established some doubt.
Now I know there are plenty of issues which need to be addressed and I know there are those who will question my point (2) above. They will argue (correctly) that it’s possible to have an average global temperature increase without a corresponding increase in upward Surface radiation. I say – fine – show us where this is happening. The temperature anomaly maps for all datasets are available so let’s see the regions of cooling (reduced surface flux) which offset the warming regions.
I also meant to mention those who query the averaging of surface flux based on the average surface temperature. Why is this relevant? Does it matter? Yes – it will change the absolute values of RE but it won’t alter the sign of the trend.
John Finn November 9, 2014 at 1:35 pm
Here’s what the author says:
and
w.
Wilis
Ok – fair enough – I could be reading too much “between the lines”. But, to give Robin the benefit of the doubt, I have interpreted his comments to mean that OLR should have declined given the current ‘pause’ in global temperatures.
John Finn November 9, 2014 at 4:19 pm
Thanks, John, but that’s my point. There’s no reason to expect any change in the OLR regardless of the change in temperatures. Output = Input ± Storage, and storage is a tiny part of that, on the order of half a watt. Our measurements are nowhere near accurate enough to measure that, so to a first order, output (OLR) has to equal input.
And input is also stable to within about ± 0.4 W/m2 (CERES data). So there is no reason to expect large or even discernible changes on OLR.
w.
Basic Questions:
How is the outgoing radiation being measured:
Spectrometer? Bolometer? bolometer and spectrometer? Bolometer with input filters.
How is the instrument calibrated:
Reference area on land?
Reference area on ocean?
Internal?
The author is welcome to correct me, but I think it is basically from satellites, with missing values interpolated. See here for details.
w.
Thanks for the link Willis.
It looks like the radiation is measured only during equator crossing.
There is probably a wealth of information if the data is gathered for the entire path:
North to south outgoing radiation field. Dynamic response of the physical processes to incoming radiation that absorb, reflect, move, and radiate energy back to space, as the Earth rotates.
Emergent phenomena comes to mind.
There is, unfortunately, no technical information about how the measurements are physically made.
Trenberth really should consider entropy, which in thermodynamics is the gap between observed heat and modelled heat. So he’s missing heat? This is what inefficiency is all about, a.k.a. entropy. Where is the entropy on his global energy budget chart?
I’ve a BSME and 30 plus years in power generation. A lot of people talk about entropy, but few really understand what it means. I’ll have to think about your definition, maybe Google one. I don’t think modeled and observed really apply.
The “entropy” is the missing information in an inference for a deductive conclusion about the outcome of the associated event. In thermodynamics these outcomes are the “accessible microstates.”
Really, “accessible microstates” Never heard of it. Will need to research. I have been down this path before.
I enjoyed Neumann’s observation about entropy.
“My greatest concern was what to call it. I thought of calling it ‘information’, but the word was overly used, so I decided to call it ‘uncertainty’. When I discussed it with John von Neumann, he had a better idea. Von Neumann told me, ‘You should call it entropy, for two reasons. In the first place your uncertainty function has been used in statistical mechanics under that name, so it already has a name. In the second place, and more important, nobody knows what entropy really is, so in a debate you will always have the advantage.”
http://en.wikipedia.org/wiki/History_of_entropy#Popular_use
Another excellent link.
http://www.asa3.org/ASA/education/origins/thermo.htm
On the relationship between information theory and thermodynamics you might find the tutorial at my Web site (http://www.knowledgetothemax.com) helpful.
nickreality65
“In the second place, and more important, nobody knows what entropy really is…”
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That I can believe.
Entropy, thermodynamics, are all about heat & energy and how they got tied up with information theory is beyond me & , IMHO, incorrect.