As readers may know, Dr. Roy Spencer and I have had a long running disagreement with the group known as “Principia Scientific International” aka the Sky Dragon Slayers after the title of their book. While I think these people mean well, they tend to ignore real world measurements in favor of self-deduced science. They claim on their web page that “the Greenhouse gas effect is bogus” and thus ignore many measurements of IR absorptivity in the atmosphere which show that it is indeed a real effect. Rational climate skeptics acknowledge that the greenhouse effect exists and functions in Earth’s atmosphere, but that an accelerated greenhouse effect due to increased CO2 emissions doesn’t rise to the level of alarm being portrayed. Yes, there’s an effect, but as recent climate sensitivity studies show, it isn’t as problematic as it is made out to be.
I don’t plan to get into that issue in this thread, as this is an hands-on experiment showing one of the thermal premises of the “slayers” in action to prove or disprove it. Most of what that group does is to spin sciencey sounding theories and pal reviewed papers by a mysterious members-only peer review system, and I have yet to any one of them try to do anything at an experimental/empirical measurement level to back up the sort of claims they make.
What started the recent row was an essay by Dr. Spencer titled Time for the Slayers to Put Up or Shut Up, which I followed on with: The Spencer Challenge to Slayers/Principia.
In their response to Dr. Spencer, they made this essay…
…and in that response was this curious graphic from Dr. Alan Siddons:
To be honest, I laughed when I saw this, because for all their claims to be “experts” on thermodynamics while telling the world that “back radiation” has no effect, this is a clear-cut case of them not knowing what they are talking about when it comes to heat -vs- visible light. Clearly, you can indeed reflect/re-emit a portion of the visible and infrared energy back to the light bulb, energy which would have been lost to the dark surroundings. There is no “extra” energy per se, just a spatial redistribution of energy (a greenhouse atmosphere has higher temperatures near the surface, but lower temperatures at high altitudes). They also seem to fail to understand how a mirror actually works, bold mine:
“Does shining a flashlight at a mirror so that all the radiation comes back to the flashlight make the flashlight shine brighter?”
While the emissivity of a glass mirror is high, no mirror reflects 100%, and mirrors of course are not lossless, so it will also absorb some Visible and IR in addition to reflecting/re-emitting some of it back. You can see this loss of energy in the FLIR camera in the video just before the mirror is removed at about 16:30.
I put their claim of “a light bulb facing a mirror does not heat up” to the experimental test.
I did several spot experiments at home over the last couple of weeks to investigate the issue empirically (since talk is cheap), and to make sure it was repeatable, while discussing the design and results with Dr. Spencer. The first two designs of the experiment had weaknesses that I was not happy with, and so it has take time to devise an experiment in a way that was fully comprehensive and uninterrupted from start to finish. For example, in my first iteration, the experiment was shot from the side (similar to the diagram), but required rotating the bulb mount assembly away from the mirror to get the temperature of the bulb surface. This wasn’t always repeatable to get the same spot on the bulb surface and it introduced variances. Another problem was that standard household bulbs had odd temperature gradients across their surface due to the way the filament is placed. The flood lamp was much more repeatable at its center. Repeatability is important, because I want others to be able to replicate this experiment without significant variances due to the equipment and how it is setup.
After ensuring the experiment works, and is repeatable/replicable, and that the control run without a mirror performed as expected, today in this WUWT-TV segment, I present the entire experiment uninterrupted as one long video. It is almost 21 minutes long, but I had no choice, because at least 16 minutes of it were required to be non interrupted to show the experiment in progress. I didn’t want anyone to be able make silly claims that the experiment was faked that there were video edits going on to change the results, such as Al Gore did in his Climate 101 video.
In my case, I did some graphic overlays to illustrate points and data, but there was no discontinuity edits of the video or audio from start to finish.
Here’s the experiment equipment list and procedure.
Equipment:
- FLIR BCAM portable infrared camera
- 65 watt incandescent flood lamp (used due to mostly flat center target surface)
- clamp on ceramic lamp base and metal electrical base/stand
- small glass wall mirror from K-Mart
- video camera to record the event
Procedure:
- Setup equipment in similar fashion to Alan Siddons figure 3 above, using stands and clamps to allow for correct height and continuous recording of FLIR camera image and a timer image.
- Focus FLIR on flat front surface of 65 watt bulb
- Start video camera to record experiment, simultaneously start digital timer
- Apply AC electrical power to 65 watt bulb
- Note FLIR temperature of bulb center surface at intervals, record that data.
- Run until equilibrium temperature is reached, which I defined would be when temperature no longer increases after a period of about 60 seconds, note that temperature, note how long that takes with timer. Record that data.
- Leaving all equipment in place and operating, place mirror perpendicular to 65 watt bulb surface, at about 3 inches away to fit scale of Alan Siddons Figure 3. This will obscure surface of bulb from FLIR camera but is required so that distance/position between bulb and FLIR is not changed, which could result in altered readings.
- Continue experiment.
- Show with video camera how equipment remains in place.
- Wait for the same amount of time as previous equilibrium temperature took to reach.
- Remove mirror, note on the FLIR camera what the surface temperature of the 65 watt light bulb is at that time.
Premise of the experiment:
If the temperature recorded by the FLIR camera is the same after the mirror has been left in place for the amount of time that it took to reach equilibrium temperature, then the Principia/Slayers claim is true.
If the temperature has risen, it falsifies their premise that “a light bulb facing a mirror does not heat up”.
Video of the experiment (with conclusion) :
Note that this is not a big budget production (it was done in the dining room of my home) so I apologize for less than perfect audio quality. BTW, the clothes iron I used as a prop was not turned on, which is plainly evident in the FLIR image. It just so happend that the tabletop ironing board and iron worked out well to position the mirror…. and I had no budget beyond a few dollars for light bulbs and lamp bases. Where’s that big oil check when we need it? /sarc
Plotted temperature data:
[Note: per a suggestion in comments, this graph was updated to show the data after the “mirror added” as dashed line, since only one datapoint (228F) was measured. – Anthony]
Supplemental information:
In a PDF file here: Slayers_lightbulb_experiment
- Temperature data recorded from the experiment to reach equilibrium temperature
- Graph of the data recorded from the experiment showing data including after removal of mirror.
- I also ran a separate control experiment for 2x of the tested equilibrium temperature time to see if bulb can reach same temperature without mirror. I’m satisfied that the experiment is properly functioning.
I have another experiment planned for part 2 that will test another claim that the Principia/Slayers routinely make. I’ll have that in a few days.
UPDATE: In the claim by Joe Postma at Principia where they stated a couple of days ago that we’d “cut and run” (obviously not, just taking our time to be careful) Alan Siddons makes this claim:
As PSI’s Alan Siddons laments:
“All of us on our side have researched and deeply pondered the actual principles of radiative heat transfer. On the other side, however, the “experts” we argue with, like Spencer, Lindzen, Monckton, Watts, just insist that a body’s radiant energy can be doubled by directing that energy back to it — even though the simplest of experiments will shows that this is false.
I’ve never made a doubling claim like that, nor am I aware that any of the others named have claimed a doubling, only that some energy will be returned, as I have just proven in the “simplest” mirror experiment postulated by Siddons.
I have to think these folks aren’t operating with a full understanding of what the physical basis is when I read things like this. This is an excerpt of this comment left in the thread below by Joe Olson where he confuses a microbolometer with doppler radar:
“Remote read IR thermometers are also used to ‘explain’ this back-radiation warming effect. These instruments work be sending out an IR signal and measuring the shift in the returned signal. ” (bold mine -A)
No, sorry, you are 100% wrong. it is a passive sensing device. No active signal is emitted.
FIGURE 1. One pixel in a microbolometer array. An infrared-absorbing surface is elevated above the substrate and thermally isolated from adjacent pixels. Low mass increases the temperature change from heat absorption. Read-out circuits typically are in the base layer, which may be coated with a reflective material to reflect transmitted IR and increase absorption of the pixel. http://www.laserfocusworld.com/articles/print/volume-48/issue-04/features/microbolometer-arrays-enable-uncooled-infrared-camera.html
Gosh, I didn’t think your misunderstanding of an IR bolometer was that distorted. No wonder you guys make the sort of way out claims you do.
A microbolometer is a specific type of bolometer used as a detector in a thermal camera. It is a grid of vanadium oxide or amorphous silicon heat sensors atop a corresponding grid of silicon. Infrared radiation from a specific range of wavelengths strikes the vanadium oxide and changes its electrical resistance. This resistance change is measured and processed into temperatures which can be represented graphically. Source: http://en.wikipedia.org/wiki/Microbolometer
You should really quit while you can Joe, you are making a fool of yourself when you make such claims that are so easily disproved. – Anthony
UPDATE3: The Principia/Slayers group has posted a hilarious rebuttal here:
http://principia-scientific.org/supportnews/latest-news/210-why-did-anthony-watts-pull-a-bait-and-switch.html
Per my suggestion, they have also enabled comments. You can go discuss it all there. – Anthony
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johnosullivan says:
May 27, 2013 at 8:39 am
“So Mr Watts, when are you going to admit we do have a time-dependent energy model, contrary to the deceitful misinformation put about by you and Dr Spencer?….”
============
Disagreement is one thing.
Accusations of “deceitful misinformation” is another.
Get ready, cus here it comes!
Jospeh A Olson: “These instruments work be sending out an IR signal and measuring the shift in the returned signal.”
Oh boy…
Oh good grief.
In http://principia-scientific.org/supportnews/latest-news/202-roy-spencer-and-wuwt-cut-and-run-on-own-greenhouse-gas-challenge.html they say
I don’t recall hearing that there was a revolt going on except maybe over that silly discussion about lunar temperatures and NASA getting it wrong back in Apollo days. Nope, that link goes to letter from 50 NASA folk last March that IIRC was more about NASA GISS procedures and policies than the existence of the Greenhouse effect.
I don’t think there’s anything in that latter that could ever be called an endorsement of the Slayer’s stand on the matter.
“richard smith says:
May 27, 2013 at 11:08 am
This test measures the temp of the bulb surface. It does not establish that reflecting radiation back to the source (the filament) increases the power output of the source. The ghg theory claims that downwelling IR causes the source of the IR, the earth’s surface, to emit more power – this is what siddons is taking issue with.”
No, the theory makes no such claim.
The earth as a system ( planet plus atmoshpere) cools by one mechanism: via radiation to space.
This happens at the ERL– the effective radiating level. When you increase GHGs you raise the ERL. Since the earth system has a negative lapse rate, this means the earth will be radiating from a higher and hence cooler region. Cooler bodies radiate less rapidly than warmer bodies so by raising the ERL to a higher cooler region the rate at which energy is lost to space is decreased.
The planet isnt warmed by back radiation. Back radiation is the effect of more GHGs in the system. The planet cools less radpidly than it would otherwise, mch the same way your coffee in a thermos is “kept warm” by the silver lining.
This happens at the ERL– the effective radiating level. When you increase GHGs you raise the ERL.
what about the desert at night.
there again the desert in the day with more moisture would make it cooler and at night warmer.
There is more than enough hard science to disprove the alarmists’ arguments and contentions, but this does mean that skeptics should stick to the hard science. Of course there is a greenhouse effect, and it varies by substance – surely nitrogen and oxygen and argon have some greenhouse effect, even if it is tiny relative to, say, water vapor. The Earth is definitely warmer, by about 15 degrees C, than it would be without its atmosphere. False or manifestly incorrect rationalizations by skeptics for rejecting AGW will only provide grist for the alarmist mill.
This debate does express a healthy willingness on the part of skeptics to mull over and argue about details, in contrast to the religious, delusional, see-no-evil-hear-no-evil-speak-no-evil dogmatism and stonewalling torpor of the alarmists, and this objectivity and skepticism among skeptics is crucial to differentiating honest science from alarmist charlatanism.
However, my concern in this debate is first and foremost that, regardless of different opinions amongst us on details, the skeptic community must be united in its general position that there is no discernible incremental effect on temperatures of increased carbon dioxide in the atmosphere, and that such effect as could ever be identified will be either nugatory or actually beneficial. At no time should we back away from this position.
The Oregon Petition statement offers a solid basis for skeptic activism, with its unequivocal declaration that there is no significant or attributable human effect on climate.
To those who think that placing the mirror on one side has any significant effect on the convective losses from the bulb really have no sense as to how convection works. The bulb heats the air directly around it by conduction, and that air rises as a result. The resulting lower pressure around the bulb can be replaced by air from virtually any direction except straight up. As long as there is not a constriction in the other directions that is so great that it actually causes a measurable pressure drop and air velocity through the constriction, there will be no noticeable effect. With over half of the potential angles for the “draw” of air to replace the rising heated air still open, there is no detectable effect in this case. (It’s easy enough to demonstrate experimentally, anyway.)
I say this as someone who regularly works with the design of cooling systems for electronics, and has to decide, for example, whether forced (fan-driven) cooling is required or not.
False or manifestly incorrect rationalizations by skeptics for rejecting AGW will only provide grist for the alarmist mill.
true,
Stomach ulcers , this has been thrown around a lot but illustrates a point beautifully ,
99% of doctors were 100% wrong about stomach ulcers , lots of scientists have been ridiculed. Thought this site was to question , not sneer.
but guess we have to stick to the greenhouse story for the moment.
I have done experiments to show willis’s steel green house effect:
http://climateandstuff.blogspot.co.uk/2013/04/the-copper-greenhouse-new-test.html
and others.
I have done a preliminary experiment to prove that a cool object can heat a warmer object:
http://climateandstuff.blogspot.co.uk/2013/03/a-cool-object-reduces-energy-loss-from.html
I am working on improving the cool adding energy to hot. But have a bit of a problem maintaining ambient to within a few 10ths of deg C. When I succeed I will put the results up. Unless the effect of ambient can be removed the slayers will find problems.
Actually, my rather expensive, 1995 first generation “Night Owl Infrared Rifle Scope” was vastly superior to a $60 IR toy, but was returned for full refund when it could not amplify ambient IR to any useable level without an additional IR light source. That light source was limited by wattage to close range. The downside is that a night feeding bunny might not see your IR source light, but anyone with a night vision scope could easily see you….from a LONG way away. The military uses IR projections on their very expensive weapon systems as well. There was no noticeable difference in my 1st generation scope based on phase of the moon or cloud cover, as ambient IR levels were not high enough. The IR thermal image systems used by law enforcement and the military far exceed the $60 IR toys, which do send a IR signal, measure the reflection and hold that value in memory until re-fired. The IR energy of your backyard barbie is NOT constant over distance, the remote reader “temperature” would be target dependent constant. However, this temperature does not indicate radiation at the REMOTE reader. Hence the resonating CO2/tuning fork analogy, CO2 molecules, resonating as photons fly, by does not constitute an additional source of energy.
http://infrared-cameras.org/thermal/rifle-scope/
This site mentions “hog hunting”, but “man-bear-pig” hunting might apply as well.
Quite the argument! Dr. Suess would have loved to be alive today. Imagine a story about buttered bread but from a global warming perspective (or in this case, the debate here). Unfortunately he was quite the liberal so I would guess he would have written a children’s book about the perils of global warming (or in this case, the debate here). For those of you not familiar with his pen, his book was about a war that started between people of different opinions on either side of a line that eventually become a tall barrier regarding which side of the bread should be buttered. Then each side decided to outbuild the other’s weapon. Alas, for Dr. Suess naivete was his lover and so he argued from a pet belief, not cold hard facts. If you want to win a debate, study that children’s book.
Anthony
Thank you for your response to my comment at 11:31am (which is appreciated). I wish to make it clear that I am not in any way criticising you. I am a firm supporter of your blog, and the valiant efforts you have made with the surface temperature station audit, and your work with respect to UHI. Your blog has won many awards, rightly deserved. I am fairly convinced that our children and grandchildren, will be indebted to you and your site.
As I said, I am not a slayer. I am a regular commentator, and have been so for many years, and I cannot recall having once made a comment in support of the slayers.
We both agree that the CO2 in the bottle experiment is flawed. The point I make that although the experiment that you conducted was thought up by the slayers, I consider that that experiment is flawed, if one is hoping to test whether cooler photons can warm a warmer object.
I may mis-understand the slayers, but my understanding is that one of their issues is that cooler photons cannot warm warmer objects. Whether they can slow down the cooling of warmer objects is a different issue (and would require different experiments). I consider (and this is no criticism of you) that their experiment is flawed, since it does not deal with the issue that they consider to be relevant. That was simply the thrust of my observation in my first point. Of course, it is up to the slayers to properly design an experiment that deals with the issues that they consider to be relevant. That is not up to you, you have more than fulfilled matters by conducting their experiment and revealing the results that you have obtained. The implications of the results is open to interpretation as others have suggested with convection issues and what would happen if the mirror was replaced with some other object etc 9or what would happen if the mirror was to be moved back in increments of a few inches at a time until it was say many feet away from the light bulb). But those issues are not a shortcoming on anything that you have done.
Of course, we all want to know to what extent the greenhouse effect is real and precisely what it can do and what its bounds are. That of course raises so many issues, not least whether the effect is already saturated, or whether it is predominantly controlled by water in its various phases and that CO2 is nothing more than a bit player (or of course, a predominant player). But it is for those that claim that the greenhouse effect is real to establish that. I consider that Trenbeth is wrong when he suggests a contraian positon on the burden.
This principle of passive reflection back to a warmer radiating body to increase the temperature of that radiating body has been exploited commercially for many years now. Many halogen incandescent light bulbs have a “dichroic” filter on the inside of the glass enclosure. This material reflects back most of the (near) infrared radiation from the filament back to the filament, while letting the visible radiation through.
The reflected radiation increases the temperature of the filament, which has two useful effects. The higher the temperature, the more of the electrical power is dissipated radiatively (since this increases roughly as T^4) and the less is dissipated conductively (since this increases roughly as T^1). Second, the higher temperature shifts the radiative spectrum more into the visible light band. Combined, these make the lamp brighter.
It is essential to realize that this temperature increase does not increase the power consumed by the bulb. In fact, it actually decreases the power use, because the resistance of the tungsten metal filament increases with temperature, decreasing the current through it (I = V / R) and the power dissipated in it (P = V^2 / R).
The Slayers claim on their websites that the producers of these bulbs are committing commericial fraud in advertising the advantages of this scheme, and that they have bamboozled the US Patent Office into granting invalid patents for “perpetual motion machines.”
we all have to be careful,
a little story this week, sea level rise, so the story goes, the last time co2 levels were 400ppm , many eons ago, the sea level was how many feet higher? but according to the new research it seems that the land they were using to measure this by was actually much lower, it has risen over the millions of years giving a false impression.
Uh, a couple questions.
1. Is the glass of the bulb itself the source of the light or is it the filament?
2. Is the filament temperature being monitored?
3. Why is this an attempt to refute a claim which isn’t made? I thought the slayers were saying the bulb won’t become brighter, not that it wouldn’t be warmer if you collected the light it emits and redirect it back onto the bulb?
I’m just not sure how measuring the temperature of the glass on a light bulb when you reflect the light back onto it is supposed to be proof or disproof of any of the points they make.
richard smith says:
May 27, 2013 at 11:08 am
This test measures the temp of the bulb surface. It does not establish that reflecting radiation back to the source (the filament) increases the power output of the source. The ghg theory claims that downwelling IR causes the source of the IR, the earth’s surface, to emit more power – this is what siddons is taking issue with.
Richard: (Sticking solely to this physical experiment and for a moment forgetting about GHGs.) You claim that on the one hand the glass of the bulb is indeed able to gain energy back from the mirror, but at the same time you seem to believe (unless I misunderstand you) that the filament is not able to gain some energy back from the glass of the bulb. Your position seems to be that that the back radiation stops with the glass bulb and that the filament remains at the same temperature with or without the presence of the mirror?
@richard:
Three million years ago, the land that was to bear ice sheets, like Greenland still & Europe, North America & Asia once & future, had not yet been so burdened.
Just goes to show that higher CO2 has little to no effect.
The Antarctic Ice Sheets formed when that continent was cut off from the others by the Southern Ocean. The northern ice sheets formed when the Americas were connected by an isthmus. In interglacials, as now, all we have left of them is mainly Greenland, but the other, bigger ones will grow larger once more, no matter how much life-, food- & fiber-giving carbon dioxide we add to the air.
Anthony,
The message is absoletely clear. However I struggle a bit with quantities. I had the opportunity once to play with an infrared thermometer used by cooks. It was a clear sky evening in winter with some cloud patches. When I aimed it at clouds it would return temperatures of say 0C to -10C, When I aimed it on the clear sky it would peg at it’s minimum of -18C,
So although I am a believer of GHG effect I could not verify it myself. No with that fabulous piece of equipment, that FLIR, you could aim it at the clear night sky, get an actual radiation temperature and convert that to the energy in W/m2. Would that be anywhere in the ballpark of raising the alleged blackbody temperatue of -18C to the global average of about 15C?
Anthony,
I was trying to be polite, pointing out the error without rubbing anyone’s nose in it. Once again, what happened to the wire? The air temperature is trivial. Why does hot air rise? Because it is less dense than colder air. How did it get less dense? It expanded. In what direction does expansion happen? All of them. Did your mirror block this movement? To some extent yes.
With all the money our society spends on heat, and electricity, the idea that we could generate all these terawatts with a simple reflector to increase the temperature, but somehow no one ever noticed this or thought to try it, well it seems a little arrogant. If this method worked it would have been adopted by your namesake James Watt, the originator of the steam engine.
Another writer mentions the net heat transfer. He seems to think that heat is also transferred from the colder object to the warmer one. The definition of “Heat” says, if an object is Heated, it gets Warmer!!! When heat is transferred the object to which heat was transferred warms. Your heater wire did not warm. At all.
This is not to say that the Greenhouse Effect does not exist. When 15-micron IR hits a CO2 molecule it is absorbed. In the denser lower atmosphere, before it could re-emit this photon, the molecule will collide with several thousand other molecules, thermalizing the energy from the photon, heating the atmosphere to the extent that 400 ppm is able. Higher in the atmosphere re-emission becomes more possible, and indeed 50% of these re-emitted photons go up, cooling the atmosphere.
Heat, it’s not just for breakfast anymore…
richard verney says:
May 27, 2013 at 1:11 pm
I may mis-understand the slayers, but my understanding is that one of their issues is that cooler photons cannot warm warmer objects. Whether they can slow down the cooling of warmer objects is a different issue…
Actually it isn’t a different issue. It’s the same thing. Anything that is capable of slowing down cooling is equally capable of causing additional warming (given an energy source, of course, for example a light bulb or the Sun).
Mods: OT (sorry) but how come my comments always end up “awaiting moderation”? Am I in someone’s bad books?!
Well, my last comment makes me look a bit silly – ignore me, sorry!
“So although I am a believer of GHG effect I could not verify it myself:
like believing in GOD.
rgbatduke says:
May 27, 2013 at 10:59 am
One can then repeat Anthony’s experiment, but instead of using a mirror, one can wrap the bulb tightly in aluminum foil in a completely distinct run.
I did do that experiment in response to a previous claim of one of the Slayers that this couldn’t increase the temperature of the filament in the bulb.
First problem was to find an incandescent bulb here (not sold anymore, except halogen types, but these have no full vacuum). But at last I did find one.
First measured the glass temperature of the front of the bulb (fitted horizontally) when the light was on after a few minutes with an infrared thermometer.
Wrapped it in aluminum foil to just outside the copper base. Made a thin opening in the foil at the front to measure the glass temperature.
Without foil: glass around 80°C
With foil: glass between 110-120°C
The intention was to let the light on until the filament burned out (normally 2000 hours), but I had to stop the experiment because the paint of the fitting started to smell, I didn’t like to burn down our house…
Next time I’ll follow the suggestion to measure the resistance of the filament with a ampère or power meter with and without foil…
@ur momisugly Ferdinand.
I have just gotten word from the VP of an electronics company lab that they are doing this experiment as you and RGB describe, including measuring resistance.
I’ll have a detailed writeup later this week. We don’t need anyone to burn their house down to refute the slayer silliness.
Anthony