Guest Post by Willis Eschenbach.
For all of its faults, the IPCC (Intergovernmental Panel on Climate Change) lays out their idea of the climate paradigm pretty clearly. A fundamental part of this paradigm is that the long-term change in global average surface temperature is a linear function of the long-term change in what is called the “radiative forcing”. Today I found myself contemplating the concept of radiative forcing, usually referred to just as “forcing”.
So … what is radiative forcing when it’s at home? Well, that gets a bit complex … in the history chapter of the Fourth Assessment Report (AR4), the IPCC says of the origination of the concept (emphasis mine):
The concept of radiative forcing (RF) as the radiative imbalance (W m–2) in the climate system at the top of the atmosphere caused by the addition of a greenhouse gas (or other change) was established at the time and summarised in Chapter 2 of the WGI FAR [First Assessment Report].
Figure 1. A graph of temperature versus altitude, showing how the tropopause is higher in the tropics and lower at the poles. The tropopause marks the boundary between the troposphere (the lowest atmospheric layer) and the stratosphere. SOURCE
The concept of radiative forcing was clearly stated in the Third Assessment Report (TAR), which defined radiative forcing as follows:
The radiative forcing of the surface-troposphere system due to the perturbation in or the introduction of an agent (say, a change in greenhouse gas concentrations) is the change in net (down minus up) irradiance (solar plus long-wave; in Wm-2) at the tropopause AFTER allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values.
In the context of climate change, the term forcing is restricted to changes in the radiation balance of the surface-troposphere system imposed by external factors, with no changes in stratospheric dynamics, without any surface and tropospheric feedbacks in operation (i.e., no secondary effects induced because of changes in tropospheric motions or its thermodynamic state), and with no dynamically-induced changes in the amount and distribution of atmospheric water (vapour, liquid, and solid forms).
So what’s not to like about that definition of forcing?
Well, the main thing that I don’t like about the definition is that it is not a definition of a measurable physical quantity.
We can measure the average surface temperature, or at least estimate it in a consistent fashion from a number of measurements. But we can never measure the change in the radiation balance at the troposphere AFTER the stratosphere has readjusted, but with the surface and tropospheric temperatures held fixed. You can’t hold any part of the climate fixed. It simply can not be done. This means that the IPCC vision of radiative forcing is a purely imaginary value, forever incapable of experimental confirmation or measurement.
The problem is that the surface and tropospheric temperatures respond to changes in radiation with a time scale on the order of seconds. The instant that the sun hits the surface, it starts affecting the surface temperature. Even hourly measurements of radiative imbalances reflect the changing temperatures of the surface and the troposphere during that hour. There is no way that we can have the “surface and tropospheric temperatures and state held fixed at the unperturbed values” as is required by the IPCC formulation.
There is a second difficulty with the IPCC definition of radiative forcing, a practical problem. This is that the forcing is defined by the IPCC as being measured at the tropopause. The tropopause is the boundary between the troposphere (the lowest atmospheric layer, where weather occurs), and the stratosphere above it. Unfortunately, the tropopause varies in height from the tropics to the poles, from day to night, and from summer to winter. The tropopause is a most vaguely located, vagrant, and ill-mannered creature that is neither stratosphere nor troposphere. One authority defines it as:
The boundary between the troposphere and the stratosphere, where an abrupt change in lapse rate usually occurs. It is defined as the lowest level at which the lapse rate decreases to 2 °C/km or less, provided that the average lapse rate between this level and all higher levels within 2 km does not exceed 2 °C/km.
This is an interesting definition. It highlights that there can be two or more layers that look like the tropopause (little temperature change with altitude), and if there is more than one, this definition always chooses the one at the higher altitude.
In any case, the issue arises because under the IPCC definition the radiation balance is measured at the tropopause. But it is very difficult to measure the radiation, either upwelling or downwelling, at the tropopause. You can’t do it from the ground, and you can’t do it from a satellite. You have to do it from a balloon or an airplane, while taking continuous temperature measurements so you can identify the altitude of the tropopause at that particular place and time. As a result, we will never be able to measure it on a global basis.
So even if we were not already talking about an unmeasurable quantity (radiative change with stratosphere reacting and surface and tropospheric temperatures held fixed), because of practical difficulties we still wouldn’t be able to measure the radiation at the tropopause in any global, regional, or even local sense. All we have is scattered point measurements, far from enough to establish a global average.
This is very unfortunate. It means that “radiative forcing” as defined by the IPCC is not measurable for two separate reasons, one practical, the other that the definition involves an imaginary and physically impossible situation.
In my experience, this is unusual in theories of physical phenomena. I don’t know of other scientific fields that base fundamental concepts on an unmeasurable imaginary variable rather than a measurable physical variable. Climate science is already strange enough, because it studies averages rather than observations. But this definition of forcing pushes the field into unreality.
Here is the main problem. Under the IPCC’s definition, radiative forcing cannot ever be measured. This makes it impossible to falsify the central idea that the change in surface temperature is a linear function of the change in forcing. Since we cannot measure the forcing, how can that be falsified (or proven)?
It is for this reason that I use a slightly different definition of the forcing. This is the net radiative change, not at the troposphere, but at the TOA (top of atmosphere, often taken to mean 20 km for practical purposes).
And rather than some imaginary measurement after some but not all parts of the climate have reacted, I use the forcing AFTER all parts of the climate have readjusted to the change. Any measurement we can take already must include whatever readjustments of the surface and tropospheric temperatures that have taken place since the last measurement. It is this definition of “radiative forcing” that I used in my recent post, An Interim Look at Intermediate Sensitivity.
I don’t have any particular conclusions in this post, other than this is a heck of a way to run a railroad, using imaginary values that can never be measured or verified.
w.
I’m not doubting what you saw, just doubting that it’s due to radiation from the ground.
I live north of Seattle, on the US northwest Pacific coast. When the ground frosts over here, any areas not hit by sun will usually stay frosted over throughout the day if the ambient temp doesn’t get too far above freezing. One road I drive to/from work has about a mile stretch that never gets direct sun. It will stay frosty all day long, even though all the other roads are dry and clear. It’s pretty dangerous.
I can often also see frost and non-frost areas side by side where the shade and sunlight meet.
Sorry, not getting the brass monkeys reference 🙁
Matthew R Marler says:
December 13, 2012 at 5:00 pm
Thanks, Matthew. You are conflating an unmeasurable variable (the radiation imbalance with the troposphere and surface fixed) and an abstract concept (“body in uniform motion”). The difference is that the radiation imbalance is a number, while a body in motion is not a number.
w.
TimTheToolMan says:
December 13, 2012 at 5:08 pm
Not sure what your point is here, Tim. Do you think that the ocean is warmer with DLR than without? I do. Do you think that the pan of water will be warmer with the DLR from the lamp than without? I do.
If you don’t, as I mentioned above, you should read “Radiating the Ocean“. There, I advance four arguments that each individually falsifies the idea that the ocean does not absorb downwelling longwave radiation.
w.
Willis write “Not sure what your point is here, Tim.”
I know. Its because you dont actually understand the issue yet otherwise you wouldn’t have put up the strawman argument.
Willis writes “If you don’t, as I mentioned above, you should read “Radiating the Ocean“. ”
Actually I think it is you who should read that thread. Specifically my comments within it 😉
Mack says:
December 13, 2012 at 6:07 pm
Mack, welcome to the discussion. There are lots of things in nature which exist only in trace amounts and yet are very important. Consider ricin, a few milligrams of which can fell an adult human. Or more to the point, consider the ozone layer, which makes up only a very trivial part of the earth’s atmosphere, less than one percent. But without it, ultraviolet would cause lots of cancer.
So the argument that CO2 is too small to have an effect just won’t wash.
w.
PS—Bear in mind that CO2 is not what is doing the heavy lifting as far as downwelling longwave radiation goes. That would be water, both in the form of water vapor and in the form of clouds.
Jeff Alberts says:
December 13, 2012 at 6:33 pm
It’s from a saying about the temperature, “Colder than the testicles on a brass monkey”, expressed in earthier language of course …
w.
TimTheToolMan says:
December 13, 2012 at 7:03 pm
Dang, that was a short conversation. Of all the available options, including actually explaining what your point was, you decided to attack me.
Perhaps people play like that where you come from, Tim. To me, it just highlights the fact that you would go to great lengths rather than answer a civil question.
I have no time for people who don’t play well with others, Tim, especially jerks that attack me rather than answer a question. I have zero tolerance for your nasty snark. Please take your accusations elsewhere, I’m done responding to you.
w.
The problem, Willis, is that there is absolutely no empirical evidence that the backradiation does anything, as some of the commenters say. Of course the backradiation exists, but It is simply a fact of physics, a property of matter. It does no necessarily have anything to do with the temperature of the atmomsphere. The construct of “backradiation” looks right, because the backraidiation does exist. But IT IS ONLY A PROPERTY OF MATTER. Only the STORAGE OF ENERGY matters. Again, again, again, again, I keep comparing Atlanta and Phoenix, same latitude and elevation——AND Phoenix on a clear day ALWAYS has a higher temperature, day and night, than Atlanta, DESPITE THE FACT THAT ATLANTA HAS AT LEAST 4 TIMES AS MUCH GREEHNOUSE GASSES AS PHOENIX! OH, ORACLE, PLEASE EXPLAIN THIS PHENOMENON! THERE IS SIMPLY NO PROOF OF THE PUTATIVE GHE! AND WITHOUT EMPIRICAL PROOF, THERE IS NO SCIENCE THERE. WILLIS, SORRY, BUT THEORY IS NOT SCIENCE!
Willis attacks me with “I have no time for people who don’t play well with others, Tim, especially jerks that attack me rather than answer a question.”
But didn’t read posts in the other thread like I asked him to. I didn’t attack you Willis, I accused you of not understanding the issue and I stand by that statement because you made a strawman argument on warming water with an IR lamp vs understanding how DLR interacts with the ocean’s cool skin.
jae says:
December 13, 2012 at 7:41 pm
Oh, please. There is plenty of evidence.
For example, there is clear empirical evidence that downwelling radiation keeps the oceans from freezing. The oceans emit about 390 W/m2. They absorb on the order of 170 W/m2 from the sun.
If there were no energy coming from DLR, then the ocean would be constantly losing about 220 W/m2 … so what keeps it from freezing, jae?
I say that the fact that the oceans are not frozen is conclusive evidence that the ocean is getting about 220 W/m2 from somewhere, otherwise it would be frozen. I say it is getting it from downwelling longwave radiation.
Where do you think the energy to keep the ocean from freezing is coming from?
w.
PS—You say:
A word to the wise. Capital letters are the equivalent of shouting, and in the amount you used them, they are the infallible mark of someone with lots of passion and not much science. You should avoid that kind of shouting if you wish to be taken seriously.
PPS—Why on earth would you expect Atlanta and Phoenix to have the same temperatures, or for Atlanta to be warmer?
Willis writes in a reply to tallbloke the other thread “You’re looking at this backwards. In a system in which the surface is maintained at a slightly lower temperature than the bulk … what happens if you forcibly warm the surface? Think it through all the way, Roger. The very surface warms … until it’s slightly warmer than the bulk … which then heats up slightly, until the surface is slightly cooler than the bulk, and the previous condition (cooler surface) is restored.
Unless your claim is that such a system can’t be heated from the top … but I don’t think that’s your claim.”
And this indicates to me that Willis gets confused by DLR “warming”. At no time is the surface temperature warmer than the bulk, heating it up. This would be a new result that Willis would have to justify by reference. Willis doesn’t understand the process of warming yet. Thats not an attack, its an observation.
The ocean is always losing energy. The relation is DLR < ULR. It doesn't matter if clouds increase the DLR by a seemingly whopping 100 W/m2 if the ocean surface is radiating 150 W/m2…its losing energy and the surface isn't heating and transferring its energy to the bulk.
When Willis writes about heat lamps its a totally different situation. In that case there is sufficient energy to actually heat the water and there is no cool skin. The water is warming and not cooling. Hence there is no reason why the energy cant conduct down into the bulk.
TimTheToolMan says:
December 13, 2012 at 7:58 pm
Ask me if I care …
w.
Willis, just chatting. I admire your work.
You are conflating an unmeasurable variable (the radiation imbalance with the troposphere and surface fixed) and an abstract concept (“body in uniform motion”). The difference is that the radiation imbalance is a number, while a body in motion is not a number.
Hmm. How about “black body radiation”? Is that an unmeasurable variable or an imaginary concept? How would you classify Avogadro’s number?
Willis,
Medical conditions caused by small amounts of anything be it ricin or ozone will not wash with me either. We are talking about heat and the physics of gases and their interaction with the sea, not the cellular biology of humans.
However, addressing your strawman arguement in the medical line……….as an example of ignorance and worry over small amounts, lets take the example of the flouridation of a towns water supply. There are people,(shall we call them ignorant cranks),who believe that increasing the F’ ion in a towns water supply from a naturally occuring say 0.02ppm.to about 0.8ppm will cause all sorts of disease,Alzhiemers, you name it, Yet there are towns in the US where there is (or was?) naturally occuring F’ in the water of 100s of ppm and the only ill effect is a mottling of the teeth.
I hope you are not among the “ignorant cranks” Willis.
But yes, you’re right about the “heavy lifting” of water,be it in the clouds,water vapour, fog, snow, ice,ocean, ie water everywhere. The Earth’s temperature is purely hydrological.
Well the heavy lifting could be hydraulic Willis 🙂 whatever.
I am not sure this is the place to post some observations that have been made by a small group of high altitude balloon flyers but I will make an attempt to say something about it which might be of value in trying to understand the strange environment of the troposphere and stratosphere. I was involved with a team that supported the NASA high altitude balloon program and also briefly the Air Force high altitude balloon program. Figure 1 is certainly an idealized view of this environment. These balloons fly for hours and sometimes days in this very strange environment. These very large balloons have been launched from all over the world with a very active Antarctic flight schedule as part of the program. Thermal effects relative to the balloon payloads (mostly radiative) are unusual since there is very little air and convective thermal exchange at altitude. Our experience of this environment can only be considered the blink of an eye in terms of months and years that go on when we are not there to observe these high altitude phenomenon. It will be very difficult to probe this dynamic environment because we just cannot position instrumentation there for very long. In situ measurement is, at this time, the only way to gather this data. The use of white paint and aluminized foil coverings can keep the balloon instruments at an acceptable temperature rather than freezing or cooking them. The “trop” is generally very cold (often -60 to -80 C) but as you pass up above it, temperatures can “warm up” to a toasty -30 C. Those boundaries are often dramatic. The short 90 minute flight of a radiosonde balloon can quickly probe this environment but most of these small “weather” balloon flights do not ever get above 100,000 feet. High altitude balloon flights are much rarer than sonde flights but they have reached altitudes of 160Kft and regularly fly at 120 to 140 Kft. The balloons fly at all hours and night flights have a really big problem of staying warm enough to stay alive. When internal temperatures in electronic packages drop much below -10 C there is a good chance they will stop functioning. The same group I worked with developed Space Shuttle and satellite payloads and we found that the thermal design for the orbiting space payloads was easy compared to balloon payloads. Being completely in the vacuum of space rather than in the last remnants of the atmosphere makes things much easier thermally. Both have some strange radiative thermal characteristics but remnants of gases complicates things for the high altitude balloon flights. Proximity to the earth’s surface for balloon flights is a thermal factor. Daytime albedo radiative effects on balloon payloads from clouds we were flying over can rapidly heat the electronics packages if we hadn’t designed the thermal shell properly. There are direct sun effects and then the reflected cloud effects from below. Antarctic flights occur when the sun never sets and there are serious snow and ice albedo effects from below. Those Antarctic flights have lasted for weeks and in at least one case the balloon did a double spiral twice around the continent (may have been about a 6 week flight)
The winds at these high altitudes give an indication that there is still plenty of “gas” up there. Winds on the way up can vary in speed and direction with speeds of 0 to 50 knots being common. Contrary to some popular ideas, winds at 120 to 140Kft can reach these same speeds (50 to 60 knots). Winds if we happen to get into the jet stream as we climb into the “trop” can reach well over 100 knots (I have seen cases of 150 knots). Winds as we reach above the trop can be as low as 5 knots and sometimes drop even lower to almost 0. Mid latitude northern hemispheric winds at altitude tend to travel from west to east during the fall months and then there is a “turn around” that occurs over a period of days and weeks in the spring where winds at altitude travel from east to west until late summer where another “turn around” occurs. This turn around effect can be seen occurring over several months through a whole series of high to lower altitudes and latitudes. It is a very complex pattern but does come in a very seasonal clockwork fashion. Some interesting box winds occur during this changeable period. A balloon traveling to altitude can “see” east west winds through a several thousand foot climb and then get into a west east wind and so forth. The balloon can travel 10s of thousands of feet and remain mostly overhead during these unusual conditions. High altitude winds in the southern hemisphere are a mirror image of the NH winds and follow the mirror image seasonal pattern.
I wanted to post these observations so that I could show you that we must be very careful about making assumptions about the environment that we think is there. There are some very dramatic differences from our surface environment that will make it hard for us to visualize what is happening there. Things are occurring up there mostly beyond our ability to “see” and since there are no manned vehicles ever flying through that area on a regular basis we really have no idea what is really happening over long periods of time except from some of these tiny snapshots of that near space overhead environment.
Bernie
TimTheToolMan says:
“And this indicates to me that Willis gets confused by DLR “warming”. At no time is the surface temperature warmer than the bulk, heating it up. This would be a new result that Willis would have to justify by reference. Willis doesn’t understand the process of warming yet. Thats not an attack, its an observation.”
When a water molecule is impacted by DLR it becomes warmer than other surface molecules and the bulk molecules below. The fact that the surface water molecules on average are cooler than the bulk water molecules below, has nothing to do with the fact that DLR caused the water to be heated. The warmed molecule does not know it belongs to the cool layer and will be happy to transfer its energy to a cooler molecule, that belongs to the warm group below it.
Feynman: Jiggling Atoms
Think about it.
Cliff
Bernie McCune says:
December 13, 2012 at 11:31 pm
Important observations, the turbulent and chaotic nature of high atmosphere winds will present a much larger surface area for thermal convective exchange and could profoundly affect vertical thermal dynamics in the atmosphere. As modellers of supernovae discovered, incorporating turbulent gas mixing can mean the difference between success and failure of effective simulation.
Willis: Thanks for your reply. I generally like your posts, but rebel when I think you overstated the skeptical case.
About the surface radiative forcing, you wrote: “Sure, you can calculate it … but is it correct?” Later, about radiative forcing in general, you wrote: “If you can’t measure it, you can’t falsify it. If you can’t falsify it, it’s not science.” These are noble sentiments, but it think they are misapplied here. Like you, I’d like to see an experiment done with the atmosphere: Forget about MODTRAN or HITRAN; just point a giant variable-wavelength IR laser at a spaceship with a photodetector and take the absorption spectrum of the whole %*&^* atmosphere! Unfortunately, we can’t instantaneously double the amount of CO2 and take a second set of measurements. We also need to know about emission.
I think our current information is a reasonable substitute for impractical experiments on the whole atmosphere. The absorption spectra of gases have been carefully studied by scientists since at least the 1930’s, long before politicization of climate science. The width of absorption lines of gases is determined by broadened by Doppler broadening (solid theoretical basis) and collision/pressure broadening (characterized imperfectly by experiment). Each GHG has been studied carefully in the laboratory and parameters characterizing the central frequency, intensity and pressure- and temperature-dependent half-width are entered in the HITRAN and MODTRAN databases (originally created for the aerospace industry). It’s trivial to pick a temperature, pressure and frequency range for a gas like CO2 and experimentally determine if the calculated and observed spectra agree. One can determine if the absorption spectrum of pure CO2 is changed by dilution with a mixture of nitrogen and oxygen. Characterizing the optical properties of GHG’s is clearly science and it probably has been done with a high degree of accuracy and reproducibility because the measurements are made in a laboratory.
The second step is to use parameters obtained from laboratory studies to calculate what should happen as radiation passes upward or downward through pre-defined atmospheres meant to be representation of various locations on earth. The radiative forcing for 2X CO2 at the tropopause has been calculated from such models independently from MODTRAN or HITRAN data by several groups and by GCM’s (which don’t use line-by-line methods). The least reliable part of this process is dealing with clouds, because we don’t have a very good handle of the temperature and emission by cloud tops. We can’t measure radiative forcing in the atmosphere itself, but the results for dozens of models have been compared. While these calculations are not “falsifiable by experiment”, they aren’t equivalent to Shakespeare’s Glendower calling the spirits from the deep. Radiative forcing isn’t anywhere near as bad as the unfalsifiable temperature predictions made for 2100 by GCMs that can’t properly model convection and clouds and that contain a dozen or more adjustable parameters. The no-feedbacks climate sensitivity of about 1 degC for 2X CO2 appears far more reliable than any estimates of its amplification by various feedbacks; another creation of climate science that haven’t been confirmed by observation. There’s so much poor science to criticize that I personally wouldn’t invest my time complaining about radiative forcing. 3.7 W/m2 translates to a temperature rise of only 1 degK (without feedbacks), so I think radiative forcing is a good issue for skeptics.
Radiative forcing is calculated at the tropopause because this is the lowest spot in the atmosphere where the temperature is controlled by radiative equilibrium. Where temperature is controlled by radiative equilibrium, radiative forcing can be converted to temperature change. Radiative forcing calculated at the surface can’t be converted to a temperature change, because some of the energy delivered by increased DLR can escape by convection rather than being used to warm the surface until radiative balance at the surface has been restored. If most of the energy delivered by increased DLR leaves by increased convection, 2X CO2 won’t produce much warming.
As for your comments about large and small changes, an average of 239 W/m2 of solar radiation reaches the surface and troposphere and an average of 333 W/m2 of DLR reaches the surface. A radiative forcing of 3.7 W/m2 for 2X CO2 is small compared with these values. You correctly point out that there can be a 1000 W/m2 difference in solar radiation between day and night, but no one is worried about the temperature difference between day and night. Even if they were, DLR is still present during the night, and radiative forcing is only a small fraction of DLR. As for temperature change, you need to work in terms of degrees Kelvin (W = oT^4), not Celsius. Global warming and climate change aren’t concerned with the temperature the difference between the Sahara and Antarctic; just a rise of a few degK on a planet where the mean temperature is 288 degK. That is a small change.
If you take the derivation of W = oT^4 with respect to temperature and do a little algebra, you get dW/W = 4*dT/T. For small changes (with no feedbacks), the percent change in T is one-fourth the percent change in W. The IPCC’s feedbacks allegedly increase this by a factor of 2 to 4.5.
Cliff writes ” The warmed molecule does not know it belongs to the cool layer and will be happy to transfer its energy to a cooler molecule, that belongs to the warm group below it.”
That would be true if there were cooler molecules below to transfer the heat to. But that’s not the case. Here is a diagram of how the very surface of the ocean looks
http://en.wikipedia.org/wiki/File:MODIS_and_AIRS_SST_comp_fig2.i.jpg
Its a logarithmic scale. Take notice of where the DLR interacts with the ocean. Thats from the dot at the very top down to about the second dot. Then below that, the ocean continues to warm for one mm or so. Thermodynamics tells us that if molecules are heated at the surface then that energy wont travel downwards because its going from a colder place to a warmer one.
Its a very interesting area and is far from intuitive.
Jeff Alberts:
At December 13, 2012 at 6:33 pm you say to Diogenes
I reply with this off-topic explanation to assist non-UK readers of WUWT who may also not understand the phrase but may be amused by its explanation.
Cold weather in the UK is often said to be,
“Cold enough to freeze the balls off a brass monkey”.
And this is often shortened to become a phrase such as “It’s brass monkeys outside” when describing cold weather.
The origin of “brass monkeys” is not documented but is often said to have a naval history. Many similar phrases do have a naval origin (e.g. ‘show a leg’). And these phrases derive from the British humour of using an innocuous phrase in a manner which could be thought to be rude (i.e. double entendre).
The story about “brass monkeys” goes like this.
Warships prepared for battle by – among other things – stacking cannon balls alongside their cannons. The lower layer of balls needed to be constrained or the entire stack would collapse and roll away. Initially, this was achieved by putting the balls in flat trays with low walls around their edges, but lifting balls from the bottom layer of the trays was difficult (fingers could not get under a heavy iron ball). This was solved by replacing each tray with a thick, wooden board which had round depressions in its top surface. The iron balls would key into the depressions which were called ‘moons’ because their appearance resembled the Moon when they were seen in the dim side-lighting within a ship.
The Royal Navy liked to place cannons beside the entrances to its shore installations and to stack pyramids of cannon balls beside the cannons. The wooden moon-keys for the balls soon degraded, so they were replaced by brass ones (and sailors were required to polish them daily).
However, brass has a much higher coefficient of thermal expansion than iron. So, as temperature drops the brass moons contract relative to the iron balls. This squeezes the balls up so they are less well keyed into place. Indeed, on very cold nights it could become cold enough to ‘freeze the balls off a brass moon-key’ and the balls would roll down the street.
Slurred pronunciation changes ‘moon-key’ to ‘monkey’.
Richard
Frank,
“There’s so much poor science to criticize that I personally wouldn’t invest my time complaining about radiative forcing. 3.7 W/m2 translates to a temperature rise of only 1 degK (without feedbacks), so I think radiative forcing is a good issue for skeptics.”
Well, science is not the stock market! Either radiative forcing has a meaning, or it does not.
Adding CO2 to the atmosphere modifies the system and in particular the lapse rate. The surface Warming expected is a result of a change in lapse rate and not an effect of extra energy. There is no reason to think that we can characterize an increase of CO2 in the unit used to describe a change in albedo or solar activity.
Willis, you are quite wrong to compare clouds to GHGs. That is an entriely different mechanism. Clouds are made up of dispersed droplets of liquid water (not gases) and they absorb a great deal of incoming radiation during the day as water has a very high specifi heat capacity. We can see that because not only do they make the ground darker, but they do so evenly across the entire visible spectrum. They do so into the infra-red as well. Consequently clouds contain a lot of heat energy. During the night they will emit that heat energy as radiation. That is like heating up a tank of hot water during the day and sitting it just above someones head at night. Yes, doing that will make you feel slightly warmer (but actually only slightly warmer because the effect due to emitting photons is actually tiny). This has nothing to do with the greenhouse effect, however, which claims that heat emitted from the ground will be absorbed and re-emitted by CO2. Even the much stronger cloud effect you have mentioned will noyl have a very small impact.
It is very difficult to get atoms to emit photons. Every method we have tried in the lab tends to end up with massive amounts of conducted heat energy. A lightbulb emits photons which are visible – but you can’t feel the heat of them when they hit your face – the energy they have is tiny (thankfully our eyes are sensitive to this tiny amount of energy). You can feel the heat of the highly energetic atoms in the filament as they cause the glass envelope of the bulb to heat and the air above it by conduction. Getting photons out of a wire is like getting blood out of a stone. Much easier to get conducted heat out.
The sun heats the Earth only because it emits such huge numbers of photons that travel to the equator of the Earth more or less completely unimpeded. Here they warm the oceans which then keep the northern lattitudes warm by a series of rather convenient ocean currents (the people of Britain should thank the people of Panama because their country keeps Britain warm). The sea temperature around the UK is about 10Celsius in the Winter and 16Celsius in the Summer. Doesn’t bear much relation to the air temperature above it (which can vary from -12 to +38) so why should CO2 make a difference?
Wills
I find all of this quite interesting and am throwing my 0.5 cents in.
The amount of radiative forcing delta between the 1950’s and today should be easily measurable. The U.S. Air Force through their “upper atmospheric research” program pushed the state of the art in IR spectrometers to the limit of measurement, or a fraction of an individual wavelength. These measurements were done in order to design the detectors for the Sidewinder and other IR heat seeking missiles. It was done at all altitudes up through at least 50-70,000 feet.
These instruments measured the extinction coefficients for CO2, N2O, H2O, CH4, and other trace gas absorbers in the atmosphere. In theory the additional CO2 and CH4 and N2O in the atmosphere should show up as a broadening of the spectrum of absorption at ALL altitudes up to an including the altitudes where the lines desaturate due to reduced pressure and temperature.
In theory additional CO2 (to use this as the example) should do two things. It should broaden the absorption spectrum (just compare the 1950’s values to today, easily measurable) AND it should increase the altitude where the lines desaturate (the altitude where the absorption lines are no longer fully saturated i.e absorbing all the radiation at that particular wavelength).
Both of these quantities are measurable and then you can back out that the effects on local temperature. Everything I have ever seen on this subject relates to classical physics and this is not a classical physics phenomenon but a Quantum Mechanical phenomenon. I could blast a terawatt per square meter at 0.7 microns but since nothing at this wavelength absorbs that energy it is as if it does not exist. Energy is only transferred between radiation to thermal motion of a molecule through absorption and emission and the time constant between the two. That does not change. If the absorption spectrum is wider, more energy is absorbed (and emitted) but during the time between the two the molecular excitation can lead to a temperature rise. These quantities are strictly governed by QM rules and the equations state that absorption and emission are themselves variable, dependent on temperature and pressure of the ENTIRE atmosphere, not just the relative increase in concentration. This is what is called collision broadening of the absorption lines, which is a gaussian to lorentz transformation of the QM spectrum.
Where is the basic QM physics in all of this? I rarely if ever see it discussed and these quantities are calcuable and measurable AND we have a huge baseline from the USAF work stretching from the early 1950’s on the subject.
denniswingo: you won’t get any sensible discussion of the IR physics from IPCC luminaries such as Pierrehumbert because their house of cards’ science is based on fake physics. Thus they assume that a pyrometer measures energy flux when all it does is to measure an assembly of Poynting Vectors in the viewing angle of the instrument. If you made that viewing angle 2pi, in zero temperature gradient. the signal would be zero. So, ‘back radiation’ isn’t real and the positive feedback doesn’t exist.
As for IR absorption, this article clearly states that it is by dribs and drabs in many collisions.:google “PhysTodayRT2011.pdf”. This is the false physics to which you refer: quantum exclusion means it can’t happen. The need for LTE means the excess energy, if there is any, pseudo-diffuses to be thermalised at heterogeneities, mainly clouds.
The caveat about excess energy is that there isn’t any because thermal emission from the atmosphere annihilates the same emission from the surface. If this didn’t happen at equal temperature, we’d be an expanding ball of plasma. These people have no shame for their actions.
@ur momisugly denniswingo
I wonder what the payload weight on modern day experiment of this sort might be? Balloon payloads continue to shrink due to all the recent (past 15 years) miniaturization process (includes lower power requirements and of course much smaller and lighter [modern Li technology] battery packs). Large latex balloons could easily probe to 80 or 90 Kft and they are relatively cheap. Latex versus polyethylene balloons rise to a burst altitude and drop the payload. Probably a couple hour flight but data can be taken going up and coming down. They also make small polyethylene balloons though. Poly balloons, however, reach a float altitude and remain there until evening and night cooling lower the float altitude a little each day/night cycle (or a slow loss of He). A large balloon can carry several tons to altitude and NASA is presently doing work on long duration balloons. This type of platform could drop sondes on a very regular basis and probe the upper atmosphere clear to the ground. There could be thousands of these probes aboard a single balloon flight. Balloon flights tend to be in the $1M range so this experiment could be done for almost nothing by today’s standards. Time to get real about this stuff and stop trying to do it with computers!
Bernie
Bernie