This will be a top “sticky” post for a day or two. New stories will appear below this one.
Readers may recall my previous essay where I pointed out how Mr. Gore’s Climate 101 Video, used in his “24 hours of climate reality”, had some serious credibility issues with editing things to make it appear as if they had actually performed the experiment, when they clearly did not. It has taken me awhile to replicate the experiment. Delays were a combination of acquisition and shipping problems, combined with my availability since I had to do this on nights and weekends. I worked initially using the original techniques and equipment, and I’ve replicated the Climate 101 experiment in other ways using improved equipment. I’ve compiled several videos. My report follows.
First. as a refresher, here’s the Climate 101 video again:
I direct your attention to the 1 minute mark, lasting through 1:30, where the experiment is presented.
And here’s my critique of it: Video analysis and scene replication suggests that Al Gore’s Climate Reality Project fabricated their Climate 101 video “Simple Experiment”
The most egregious faked presentation in that video was the scene with the split screen thermometers, edited to appear as if the temperature in the jar of elevated CO2 level was rising faster than the jar without elevated CO2 level.
It turns out that the thermometers were never in the jar recording the temperature rise presented in the split screen and the entire presentation was nothing but stagecraft and editing.
This was proven beyond a doubt by the photoshop differencing technique used to compare each side of the split screen. With the exception of the moving thermometer fluid, both sides were identical.

Exposing this lie to the viewers didn’t set well with some people, include the supposed “fairness” watchdogs over at Media Matters, who called the analysis a “waste of time”. Of course it’s only a “waste of time” when you prove their man Gore was faking the whole thing, otherwise they wouldn’t care. Personally I consider it a badge of honor for them to take notice because they usually reserve such vitriol for high profile news they don’t like, so apparently I have “arrived”.
The reason why I took so much time then to show this chicanery was Mr. Gore’s pronouncement in an interview the day the video aired.
His specific claim was:
“The deniers claim that it’s some kind of hoax and that the global scientific community is lying to people,” he said. “It’s not a hoax, it’s high school physics.” – Al Gore in an interview with MNN 9/14/2011
So easy a high school kid can do it. Right?
Bill Nye, in his narration at 0:48 in the video says:
You can replicate this effect yourself in a simple lab experiment, here’s how.
…and at 1:10 in the video Nye says:
Within minutes you will see the temperature of the bottle with the carbon dioxide in it rising faster and higher.
So, I decided to find out if that was true and if anyone could really replicate that claim, or if this was just more stagecraft chicanery. I was betting that nobody on Gore’s production team actually did this experiment, or if they did do it, it wasn’t successful, because otherwise, why would they have to fake the results in post production?
The split screen video at 1:17, a screencap of which is a few paragraphs above shows a temperature difference of 2°F. Since Mr. Gore provided no other data, I’ll use that as the standard to meet for a successful experiment.
The first task is to get all the exact same equipment. Again, since Mr. Gore doesn’t provide anything other than the video, finding all of that took some significant effort and time. There’s no bill of materials to work with so I had to rely on finding each item from the visuals. While I found the cookie jars and oral thermometers early on, finding the lamp fixtures, the heat lamps for them, the CO2 tank and the CO2 tank valve proved to be more elusive. Surprisingly, the valve turned out to be the hardest of all items to locate, taking about two weeks from the time I started searching to the time I had located it, ordered it and it arrived. The reason? It isn’t called a valve, but rather a “In-Line On/Off Air Adapter”. Finding the terminology was half the battle. Another surprise was finding that the heat lamps and fixtures were for lizards and terrariums and not some general purpose use. Fortunately the fixtures and lamps were sold together by the same company. While the fixtures supported up to 150 watts, Mr. Gore made no specification on bulb type or wattage, so I chose the middle of the road 100 watt bulbs from the 50, 100, and 150 watt choices available.
I believe that I have done due diligence (as much as possible given no instructions from Gore) and located all the original equipment to accurately replicate the experiment as it was presented. Here’s the bill of materials and links to suppliers needed to replicate Al Gore’s experiment as it is shown in the Climate 101 video:
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BILL OF MATERIALS
QTY 2 Anchor Hocking Cookie Jar with Lid
http://www.cooking.com/products/shprodde.asp?SKU=187543
QTY2 Geratherm Oral Thermometer Non-Mercury http://www.pocketnurse.com/Geratherm-Oral-Thermometer-Non-Mercury/productinfo/06-74-5826/
QTY 2 Globe Coin Bank
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=150661053386
QTY 2 Fluker`s Repta Clamp-Lamp with Ceramic Sockets for Terrariums (max 150 watts, 8 1/2 Inch Bulb) http://www.ebay.com/itm/Fluker-s-Repta-Clamp-Lamp-150-watts-8-1-2-Inch-Bulb-/200663082632
QTY2 Zoo Med Red Infrared Heat Lamp 100W
http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=200594870618
QTY1 Empire – Pure Energy – Aluminum Co2 Tank – 20 oz
http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=190563856367
QTY 1 RAP4 In-Line On/Off Air Adapter
http://www.rap4.com/store/paintball/rap4-in-line-on-off-air-adapter
QTY 1 flexible clear plastic hose, 48″ in length, from local Lowes hardware to fit RAP4 In-Line On/Off Air Adapter above.
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Additionally, since Mr. Gore never actually proved that CO2 had been released from the CO2 paintball tank into one of the jars, I ordered a portable CO2 meter for just that purpose:
It has a CO2 metering accuracy of: ± 50ppm ±5% reading value. While not laboratory grade, it works well enough to prove the existence of elevated CO2 concentrations in one of the jars. It uses a non-dispersive infrared diffusion sensor (NDIR) which is self calibrating, which seems perfect for the job.
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Once I got all of the equipment in, the job was to do some testing to make sure it all worked. I also wanted to be sure the two oral thermometers were calibrated such they read identically. For that, I prepared a water bath to conduct that experiment.
CAVEAT: For those that value form over substance, yes these are not slick professionally edited videos like Mr. Gore presented. They aren’t intended to be. They ARE intended to be a complete, accurate, and most importantly unedited record of the experimental work I performed. Bear in mind that while Mr. Gore has million$ to hire professional studios and editors, all I have is a consumer grade video camera, my office and my wits. If I were still working in broadcast television, you can bet I would have done this in the TV studio.
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STEP 1 Calibrate the Oral Thermometers
Here’s my first video showing how I calibrated the oral thermometers, which is very important if you want to have an accurate experimental result.
Note that the two thermometers read 98.1°F at the conclusion of the test, as shown in this screencap from my video @ about 5:35:
STEP 2 Calibrate the Infrared Thermometer
Since I plan to make use of an electronic Infrared thermometer in these experiments, I decided to calibrate it against the water bath also. Some folks may see this as unnecessary, since it is pre-calibrated, but I decided to do it anyway. It makes for interesting viewing
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STEP 3 Demonstrate how glass blocks IR using the Infrared Thermometer
The way an actual greenhouse works is by trapping infrared radiation. Glass is transparent to visible light, but not to infrared light, as we see below.
![greenhouseeffects[1]](http://wattsupwiththat.files.wordpress.com/2011/10/greenhouseeffects1.jpg?resize=400%2C459&quality=83)
By itself, that would be enough to declare the experiment invalid, but not only will I show the problem of the experimental setup being flawed, I’ll go to full on replication.
Using the warm water bath and the infrared thermometer, it becomes easy to demonstrate this effect.
Since Mr. Gore’s experiment used infrared heat lamps illuminating two glass jars, I decided to test that as well:
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STEP 4 Replicating Mr. Gore’s Climate 101 video experiment exactly, using the same equipment – duration of 10 minutes
At 1:10 in the Climate 101 video narrator Bill Nye the science guy says:
Within minutes you will see the temperature of the bottle with the carbon dioxide in it rising faster and higher.
Since this is “simple high school physics” according to Mr. Gore, this should be a cinch to replicate. I took a “within minutes” from the narration to be just that, so I tried an experiment with 10 minutes of duration. I also explain the experimental setup and using the CO2 meter prove that CO2 is in fact injected into Jar “B”. My apologies for the rambling dialog, which wasn’t scripted, but explained as I went along. And, the camera work is one-handed while I’m speaking and setting up the experiment, so what it lacks in production quality it makes up in reality.
You’ll note that after 10 minutes, it appears there was no change in either thermometer. Also, remember these are ORAL thermometers, which hold the reading (so you can take it out of your mouth and hand it to mom and ask “can I stay home from school today”?). So for anyone concerned about the length of time after I turned off the lamps, don’t be. In order to reset the thermometers you have to shake them to force the liquid back down into the bulb.
Here’s the screencaps of the two thermometer readings from Jar A and B:
Clearly, 10 minutes isn’t enough time for the experiment to work. So let’s scratch off the idea from narration of “a few minutes” and go for a longer period:
RESULT: No change, no difference in temperature. Nothing near the 2°F rise shown in the video. Inconclusive.
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STEP 5 Replicating Mr. Gore’s Climate 101 video experiment exactly, using the same equipment – duration of 30 minutes
Ok, identical setup as before, the only difference is time, the experiment runs 30 minutes long. I’ve added a digital timer you can watch as the experiment progresses.
And here are the screencaps from the video above of the results:
RESULT: slight rise and difference in temperature 97.4°F for Jar “A” Air, and 97.2°F for Jar “B” CO2. Nothing near the 2°F rise shown in the video.
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STEP 6 Replicating Mr. Gore’s Climate 101 video experiment, using digital logging thermometer – duration of 30 minutes
In this experiment, I’m substituting the liquid in glass oral thermometers with some small self contained battery powered digital logging thermometers with LCD displays.
This model:
Details here
Specification Sheet / Manual
USB-2-LCD+ Temperature Datalogger
I used two identical units in the experiment replication:
And here are the results graphed by the application that comes with the datalogger. Red is Temperature, Blue is Humidity, Green is dewpoint
The graphs are automatically different vertical scales and thus can be a bit confusing, so I’ve take the raw data for each and graphed temperature only:
After watching my own video, I was concerned that maybe I was getting a bit of a direct line of the visible portion of the heat lamp into the sensor housing onto the thermistor, since they were turned on their side. So I ran the experiment again with the dataloggers mounted vertically in paper cups to ensure the thermistors were shielded from any direct radiation at any wavelength. See this video:
Both runs of the USB datalogger are graphed together below:
RESULTS:
Run 1 slight rise and difference in temperature 43.5°C for Jar “A” Air with Brief pulse to 44°C , and 43.0°C for Jar “B” CO2.
Run 2 had an ended with a 1°C difference, with plain air in Jar A being warmer than Jar “B with CO2.
Jar “A” Air temperature led Jar “B” CO2 during the entire experiment on both runs
The datalogger output files are available here:
JarA Air only run1.txt JarB CO2 run1.txt
JarA Air only run2.txt JarB CO2 run2.txt
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STEP 7 Replicating Mr. Gore’s Climate 101 video experiment exactly, using a high resolution NIST calibrated digital logging thermometer – duration of 30 minutes
In this experiment I use a high resolution (0.1F resolution) and NIST calibrated data logger with calibrated probes. Data was collected over my LAN to special software. This is the datalogger model:
Data sheet: Model E Series And the software used to log data is described here
Here’s the experiment:
I had to spend a lot of time waiting for the Jar “B” probe to come to parity with Jar “A” due to the cooling effect of the CO2 I introduced. As we all know, when a gas expands it cools, and that’s exactly what happens to CO2 released under pressure. You can see the effect early in the flat area of the graph below.
Here’s the end result screencap real-time graphing software used in the experiment, click the image to expand the graph full size.
RESULTS:
Peak value Jar A with air was at 18:04 117.3°F
Peak value Jar B with CO2 was at 18:04 116.7°F
Once again, air led CO2 through the entire experiment.
Note that I allowed this experiment to go through a cool down after I turned off the Infrared heat lamps, which is the slope after the peak. Interestingly, while Jar “A” (probe1 in green) with Air, led Jar “B” (Probe 2 in red) with CO2, the positions reversed shortly after the lamps turned off.
The CO2 filled jar was now losing heat slower than the plain air jar, even though plain air Jar “A” had warmed slightly faster than the CO2 Jar “B”.
Here’s the datalogger output files for each probe:
Climate101-replication-Probe01-(JarA – Air).csv
Climate101-replication-Probe02-(JarB – CO2).csv
Climate101-replication-Probe03-(Ambient Air).csv
What could explain this reversal after the lamps were turned off? The answer is here at the Engineer’s Edge in the form of this table:
Heat Transfer Table of Content
This chart gives the thermal conductivity of gases as a function of temperature.
Unless otherwise noted, the values refer to a pressure of 100 kPa (1 bar) or to the saturation vapor pressure if that is less than 100 kPa.
The notation P = 0 indicates the low pressure limiting value is given. In general, the P = 0 and P = 100 kPa values differ by less than 1%.
Units are milliwatts per meter kelvin.
Note the values for Air and for CO2 that I highlighted in the 300K column. 300K is 80.3°F.
Air is a better conductor of heat than CO2.
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So, here is what I think is going on with Mr. Gore’s Climate 101 experiment.
- As we know, the Climate101 video used infrared heat lamps
- The glass cookie jars chosen don’t allow the full measure of infrared from the lamps to enter the center of the jar and affect the gas. I showed this two different ways with the infrared camera in videos above.
- During the experiments, I showed the glass jars heating up using the infrared camera. Clearly they were absorbing the infrared energy from the lamps.
- The gases inside the jars, air and pure CO2 thus had to be heated by secondary heat emission from the glass as it was being heated. They were not absorbing infrared from the lamps, but rather heat from contact with the glass.
- Per the engineering table, air is a better conductor of heat than pure CO2, so it warms faster, and when the lamps are turned off, it cools faster.
- The difference value of 2°F shown in the Climate 101 video split screen was never met in any of the experiments I performed.
- The condition stated in the Climate 101 video of “Within minutes you will see the temperature of the bottle with the carbon dioxide in it rising faster and higher.” was not met in any of the experiments I performed. In fact it was exactly the opposite. Air consistently warmed faster than CO2.
- Thus, the experiment as designed by Mr. Gore does not show the greenhouse effect as we know it in our atmosphere, it does show how heat transfer works and differences in heat transfer rates with different substances, but nothing else.
Mr. Gore’s Climate 101 experiment is falsified, and could not work given the equipment he specified. If they actually tried to perform the experiment themselves, perhaps this is why they had to resort to stagecraft in the studio to fake the temperature rise on the split screen thermometers.
The experiment as presented by Al Gore and Bill Nye “the science guy” is a failure, and not representative of the greenhouse effect related to CO2 in our atmosphere. The video as presented, is not only faked in post production, the premise is also false and could never work with the equipment they demonstrated. Even with superior measurement equipment it doesn’t work, but more importantly, it couldn’t work as advertised.
The design failure was the glass cookie jar combined with infrared heat lamps.
Gore FAIL.
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UPDATE: 4PM PST Some commenters are taking away far more than intended from this essay. Therefore I am repeating this caveat I posted in my first essay where I concentrated on the video editing and stagecraft issues:
I should make it clear that I’m not doubting that CO2 has a positive radiative heating effect in our atmosphere, due to LWIR re-radiation, that is well established by science. What I am saying is that Mr. Gore’s Climate Reality Project did a poor job of demonstrating an experiment, so poor in fact that they had to fabricate portions of the presentation, and that the experiment itself (if they actually did it, we can’t tell) would show a completely different physical mechanism than what actually occurs in our atmosphere.
No broader take away (other than the experiment was faked and fails) was intended, expressed or implied – Anthony















R. Gates says:
October 19, 2011 at 10:31 am
That would have eventually caused ice to form on the sides of the containers and would have badly skewed any sensitivity in temperatures they were looking for. (Take a can of liquid air used for cleaning electronic equipment and blow it on your other hand and see how long that “experiement” lasts.)
(Warning, do not try this at home unless you can dial medical help with the other hand.)
For those interested:
For a real experiment with IR back radiation, see
Roy Spencer, The Box, measuring back radiation
http://www.drroyspencer.com/2010/08/help-back-radiation-has-invaded-my-backyard/
Inspiring dedication and thoroughness Anthony. Thank you!
“The deniers claim that it’s some kind of hoax and that the global scientific community is lying to people,”- Gore.
It defies my common sense to make such claims and then fake an experimental result. I could understand (but not condone) if the original experiment was edited to make it easier to present the results to the audience. But edited to produce a result that doesn’t exist is really absurd given such grand pronouncements. The fact this experiment is a poor representation of real world is rather beside the point. What these results really show is the cognative dissonance for those involved.
ps Dr Spencer’s “only 1 Watts per square meter” comment made me spew my coffee! Thanks for the howl.
Great work. I love this science site.
No it doesn’t. The idea that Greenhouses warm by trapping IR was debunked by Robert Wood nearly a hundred years ago.
It doesn’t invalidate what you’ve done Anthony, but experimental facts are experimental facts.
David Springer:
Exactly, but for the millionth time, Anthony was repeating Gore’s experimental setup to show it doesn’t work, not trying to demonstrate whether, if properly measured, CO2 acts as an IR thermal insulator. Anthony’s results are exactly what are expected given Gore/Nye’s experimental setup. Namely, it doesn’t heat up as quickly, doesn’t get as hot in the center for the same forcing, and cools more slowly. This result follows directly from the Fourier heat equation.
It would be nice if some of you critics (including Matt and stevo) would admit that Gore’s experiment clearly doesn’t work as advertised and the results were clearly faked to show an opposite effect as what would be really expected from that experimental setup.
I’ve seen students get kicked out of science programs over that type of academic dishonesty.
The use of Bill Nye in this fraud says more about the shabby state of American science than it does about Gore.
This stuff is too good to be true, how funny. Thank you Anthony.
“Good evening Mr. Watts. Please have a seat. Mr. Gore will be with you in a minute.”
[the sound of someone lying on the ground kicking and screaming a few rooms away]
[a muffled voice – an ensuing argument – the door slams]
“Mr. Watts, Mr. Gore is unavailable. Perhaps another night. But thanks for coming. He really does appreciate your interest in his work.”
R Gates:
CO2 is heavier than air, so it should pool inside of the container. When you close the container and heat it, it should act as a “well mixed gas” due to convective forcing, so that isn’t the problem here.
One extra thing I would have done is swap the gases so ‘A’ gets the CO2 and ‘B’ gets air leaving everything else exactly the same. Similar results from that would then nullify all other factors like light bulb variation, glass thickness, unequal mojo, etc.
Maybe your chackra is lacking compared to Gore’s. A little vaseline might help.
I hope he doesn’t plan to replicate this experiment with methane. Just imagine….
OMG! I used to be a CAGW believer. But now it’s clear to me! CO2 does not absorb infrared radiation.
You should send this study to Nature immediately. Your results are so clear, it will upset the whole of scientific endeavour. I’m sure you’ll win a Nobel Prize!
You’re the best, most rigorous and skeptical scientist in the world.
I can’t believe that thousands of scientists have been led into thinking CO2 absorbed longwave radiation, when it’s so easy to disprove…
The claim of the greenhouse effect isn’t that CO2 traps more heat in glass jars, but rather that it prevents more heat from escaping to space. Neither Gore’s nor the Myth Buster’s experiment prove or disprove that.
The Mythbusters experiment was a complete farce as well. Any takers?
Anthony,
This comment is coming from someone who did those type of experiments for over 20 years and you did great. What non-experimentalists do not appreciate is how much different situation is when one compares 100% CO2 atmosphere with 0.04% one and using CO2 argument as the driving force for temperature increase. I think you should offer this video to BBC and challeng them to prove it wrong. If they can’t, then you should offer it to the school science teachers in USA, UK and Australia to start with.
Darko
Lucy Skywalker says:
October 19, 2011 at 10:42 am
It’s telling that the level of trolling here is low.
I’ve never seen any “basic experiment” that shows the effect of CO2 as GHG in the atmosphere. I always felt that IPCC should have been presenting it, in checkable form, in their Climate Science 101 if it was real. The fact that “real scientist” Bill Nye went along with this now-proven fraud is all the more evidence that no such “basic experiment” exists – surely he would have known about it….
____
Lucy, I think you are missing the point here. Anthony never doubted the greenhouse effect of CO2 in the atmosphere or that CO2 acts as a greenhouse gas, and their are many skeptics who don’t doubt these basic principles. What was at issue was the set up of the 101 experiment.
There are lots of simple and complex experiments that can show both that CO2 absorbs certain frequencies of EM radiation and that it acts as a greenhouse gas. The BBC experiment is one of the simple ones, and worked for reasons the 101 did not. They only appear to be similar experiments, but Anthony did a good job of pointing out why one would fail and one would work.
Only had time to read through a few replies, but I have a couple of quick thoughts:
I also was bothred from Day 1 by the poor detail provided by Mythbusters for their experiment. But in looking at it again it dawned on me that it’s likely the two controls were the outside two boxes (I looked hard for confirmation of that but just couldn’t find it) and that the “experiements” were the two inside boxes. Given the experimental setup I think the inside boxes would each see light from two surrounding “experiments” pretty well and therefore be receiving more light than the outside boxes which were seeing light from only one other “experiment.” This might well explain the different outcomes.
Anthony – others have already commented that the null experiment would be a useful addition. Given available time and interest, I agree. But I also think that if you take the time for the null experiment you should also replicate the final experiment with one modification. The carbin dioxide you’re adding is displacing the other IR active gas in the container: water. You should place a Petri dish in each container with 1/2″ of water in each so that when the experiments equilibrate thermally after adding the carbon dioxide you can be sure the partial pressure of water in each container is similar.
Cheers.
This is REAL science!
R. Gates said:
Ok, let’s hear how Anthony pointed out why one would work. Done properly it will never “work”.
The reason why the BBC experiment “worked” is because the Ideal Gas Law was being verified, not the greenhouse effect. Sheesh. This shouldn’t be that complicated to understand.
The question remains. Does the “greenhouse effect” behave the same way a real glass greenhouse does? My three examples above says it does. NASA agrees:
NASA
The “greenhouse effect” is the warming of climate that results when the atmosphere traps heat radiating from Earth toward space. Certain gases in the atmosphere resemble glass in a greenhouse, allowing sunlight to pass into the “greenhouse,” but blocking Earth’s heat from escaping into space.
http://www.gsfc.nasa.gov/gsfc/service/gallery/fact_sheets/earthsci/green.htm
So where is the missing hot spot? Down under Trenberth’s missing heat sinking to the deep abyss of the ocean? This inconvenient missing component is a key tenet of the “greenhouse effect” AGW meme, and the whole intent of Santer et al 2008 was to show the models were correct; that the basic physics built into GCM’s match observations.
Will you marry me?
Love it! Way to bust a Gorebal Warming Myth! Just like Myth Busters only without using high explosives. I would like to see how you would design this experiment to give it the best chance to succeed (ie use ir transparent jars and shortwave lamps) in an effort to replicate how the greenhouse effect actually works. Then see if you can get it to blow up!
@Merrick
If I set up and conducted an experiment like Mythbusters, I’d be escorted to the door, boxes packed. It was complete FUBAR from the start. In Anthony’s case, unless the jars were air tight or had minimal leakage, the results will repeat, or inversely correlate from jar to jar.
Anthony did not do this, but his was to replicate the Gore fraud. Never, ever, ever is an experiment done without including a correlation run for each box compared to the other. A control is worthless if the results do not correlate between boxes. It is inconceivable Mythbusters would not know this.
DR – I think your resources are flawed. A greenhouse works because the AIR is trapped, not because the HEAT is trapped. During the day the sun heats the ground, the ground heats the air, but it never gets very warm near the ground because that air is contantly being replaced with cooler air that wasn’t close to the ground and didn’t get warmed. This mixing keeps the temperature differential for air at the ground and up to a few hundred feet almost zero. The walls of the greenhouse prevent the mixing, so the air in the greenhouse warms faster and higher than surrounding air. That is not terribly similar to what CO2 in the atmosphere does.
John A says:
October 19, 2011 at 11:03 am
The way an actual greenhouse works is by trapping infrared radiation. Glass is transparent to visible light, but not to infrared light, as we see below.
No it doesn’t. The idea that Greenhouses warm by trapping IR was debunked by Robert Wood nearly a hundred years ago.
It doesn’t invalidate what you’ve done Anthony, but experimental facts are experimental facts.
———————————————————–
Further to John A’s point, I have a condo with a fairly long entrance (60 ft) that is all glass on one side. The walls are white and the floor is a dark wood.
If I close the curtains the hallway stays cool. If I leave them open, the floor is much warm to the feet and the hallway is considerably hotter.
So if I have the curtains closed, the visible light still travels through the glass and is presumably converted to IR which is then prevented from leaving back through the glass. To make things even more confusing, the area between the glass and the curtain doesn’t heat up very much. The curtains are very light in color. The windows are always closed.
My belief is that the IR is not created until the visible light is absorbed by the dark floor but I have no idea.