Model CO2 as Greenhouse Gas: Tips & Results

[BrianG]

The effect of doubling CO2 is for conditions on Earth, where CO2 is a small part of the atmosphere. It's a fairly well constrained result that doubling CO2 in Earth's atmosphere, and holding everything else fixed, will give an additional 3.7 W/m² of forcing.

You can get approximately the right result here by using a crude estimate of

$$Q = \epsilon \sigma T^4$$​

Q here is the energy out the top of the atmosphere, T is the absolute temperature at the surface, σ is the Stefan-Boltzmann constant, and ε is a constant, written here a bit like emissivity, although it is is not actually an emissivity term.

T at Earth's surface is about 298, and Q is about 239 W/m²...

This is tested by experiment? Please cite; I am interested in experimental tests on CO2's greenhouse effect.

 

[BrianG]

But these formulas aren't tested in the lab? Can you cite any experimental tests?

 

[Skyhunter]

They are not tested in a lab, they are based on the results of extensive observations of the atmosphere.

 

[mheslep]

...
While average Antarctic sea ice has increased slightly, this is a function of ozone depletion and it's effect on circulation patterns in the Antarctic, not some alleged global cooling. other areas of the Antarctic, especially the western peninsula, are experiencing a sharp decline in average sea ice extent.

Do you have sources for this, especially the implication that ozone depletion is responsible for Antarctic sea ice creation via currents? Currents and circulation also have a great deal to do with Arctic ice depletion.[1]

...Antarctic total ice mass is decreasing to the tune of about 84 gigatons of ice per year.

That statement would seem to conflict with this

The Antarctic ice sheet is likely to gain mass because of greater precipitation,

http://www.grida.no/publications/other/ipcc_tar/?src=/climate/ipcc_tar/wg1/008.htm

[1]http://www.nasa.gov/vision/earth/lookingatearth/quikscat-20071001.html

Nghiem said the rapid decline in winter perennial ice the past two years was caused by unusual winds. "Unusual atmospheric conditions set up wind patterns that compressed the sea ice, loaded it into the Transpolar Drift Stream and then sped its flow out of the Arctic," he said. When that sea ice reached lower latitudes, it rapidly melted in the warmer waters.

"The winds causing this trend in ice reduction were set up by an unusual pattern of atmospheric pressure that began at the beginning of this century," Nghiem said.

 

[chriscolose]

For those interested, spectroscopic databases have been compiled for all the gases in the Earth's atmosphere (e.g., HITRAN) These databases contain line centers and parameters describing line shape as a function of pressure and temperature and provide the amount of absorption to very high spectral resolution.

Before reading too much into much simpler stuff then the approach of modern line-by-line radiative transfer codes and climate models, it may be worth reading some online material on the downfalls of simple experiments, like measuring radiation decay through a tube. See http://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument-part-ii/ (and part 1) and check out Spencer Weart's site as well.

 

[Skyhunter]

Do you have sources for this, especially the implication that ozone depletion is responsible for Antarctic sea ice creation via currents? Currents and circulation also have a great deal to do with Arctic ice depletion.[1]
That statement would seem to conflict with this

It is in the Antarctic section. (large PDF 15mb)
http://www.ncdc.noaa.gov/oa/climate/research/2008/ann/bams/full-report.pdf

The TAR is a bit outdated and it appears you are confusing Antarctic land ice with Antarctic sea ice, and the Arctic with the Antarctic.

The State of the climate report I cited has the most comprehensive up to date assessment since the 4AR. The sections on the Arctic and Antarctic should help clear up your confusion.

 

[mheslep]

It is in the Antarctic section. (large PDF 15mb)
http://www.ncdc.noaa.gov/oa/climate/research/2008/ann/bams/full-report.pdf

Thanks, I'll take a look.

The TAR is a bit outdated and it appears you are confusing Antarctic land ice with Antarctic sea ice, and the Arctic with the Antarctic.

No, I was drawing attention to the the way in which you were singling out winds and currents only for the Antarctic explanation; they also factor greatly in explaining Arctic melts as explained by Nghiem.

 

[BrianG]

They are not tested in a lab, they are based on the results of extensive observations of the atmosphere.

How do you isolate the effect of CO2? Are you saying the greenhouse effect is too small for exprimental measurement?

 

[sylas]

How do you isolate the effect of CO2? Are you saying the greenhouse effect is too small for exprimental measurement?

It is isolated by the experiments we have been discussing already, starting with Tyndal in the 19th century.

What you can't measure in an experiment is the total effect on Earth's climate. You can, however, confirm the basic underlying physics which is involved.

We know that carbon dioxide absorbs infrared radiation. We know how it works now in considerable detail, thanks to quantum mechanics; and there is a massive body of experimental work confirming the relevant physics. You can now calculate the absorption spectrum for different gases in considerable detail. The warming effect of this on a planet is consequence of very basic physics indeed. We've not conducted experiments on a planet as such, but experiments on radiation and thermodynamics confirms well beyond any credible doubt that an atmosphere which absorbs infrared radiation will give a higher surface temperature.

This is called the "atmospheric greenhouse effect". You still get people who deny that a greenhouse effect exists at all, but that is pretty much the young Earth creationism of climate science.

On the other hand, there is the effect of changing concentrations of greenhouse gases. This means quantifying the effect, in terms of concentrations; and that is not something you can do directly in a lab either. What you can do in a lab confirms that increasing carbon dioxide will give more absorption of infrared; but you can't just do a simple scale from a gas cell to an atmosphere. To quantify the effect well enough to infer the effect of changing concentrations on a planet is more difficult.

This problem can be broken into two parts; one of which is solved and one of which is not.

We know very well how carbon dioxide and other gases interact with radiation. We measure the spectum of light in the atmosphere (backradiation, radiation out to space, flux at different levels, and so on) and there's a well developed and tested theory associated with that; so that you can calculate to quite good accuracy how much additional energy is available with a change in concentrations.

What is hard is to tell how much the temperature of the surface changes in response to additional energy. Again; the relevant physics is fine, but the problem is the sheer scale of the major cycles and processes interacting in the climate system. You can test various parts of it, but to actually measure the temperature changes due to changing atmospheric composition can't be done directly. You can't separate out the causes and effects as you can in a lab.

Upshot is.

We know, as well as we know anything at all in science, that there's a greenhouse effect. There are all kinds of experiments, some of which we have discussed here, which show that carbon dioxide, water, methane, flourocarbons, and various other gases will absorb thermal radiation and heat up as a result.

We know, to a very high level of confidence, that the effect of a gas like carbon dioxide is logarithmic, and we've got a good handle on the factor. A doubling of CO2 concentrations will give a certain amount of additional energy at the surface of the planet... about 3.7 W/m². That's the result of a pretty detailed calculation over the surface of the Earth and and though all lines of the spectrum, using well tested physics. You can't measure that number directly; it is a calculation for a whole planet. But there's no credible doubt on the number beyond comparatively small errors of no more than 10%.

We have a rough idea only of how much temperature change that leads to, in the long run. It's something from 2 to 4.5 degrees. That based on empirical and theoretical studies.

Cheers -- sylas

 

[Skyhunter]

No, I was drawing attention to the the way in which you were singling out winds and currents only for the Antarctic explanation; they also factor greatly in explaining Arctic melts as explained by Nghiem.

I was addressing a direct point about the Antarctic, not ignoring the conditions in the Arctic that led to the rapid decrease in Arctic sea ice. I was trying to keep it brief since it is off topic.

The conditions that led to the sharp decline in Arctic sea ice were not unprecedented. The difference in 2007 was the abundance of thin ice that was more suscpeptible to being blown into more temperate waters by the wind.

The development of a relatively younger, thinner ice cover coincided with a strong, persistent positive pattern in the AO from 1989 to 1995 (see Figure A1). These characteristics make the current ice cover intrinsically more susceptible to the effects of atmospheric and oceanic forcing. It is of crucial importance to observe whether the sea ice cover will continue its decline or recover under the recent more neutral AO conditions (Lindsay and Zhang, 2005). http://www.arctic.noaa.gov/report07/seaice.html"

http://nsidc.org/arcticseaicenews/" sea ice extent there has been no recovery of Arctic sea ice.

http://www.antarctica.ac.uk/press/press_releases/press_release.php?id=838"

 

[mheslep]

http://nsidc.org/arcticseaicenews/" sea ice extent there has been no recovery of Arctic sea ice.

<shrug>So far in 2009 the Arctic extent is certainly lower than the long term mean, yet 2009 has been an improvement over 2007, and April 2009 almost rejoined the mean.

 

[Skyhunter]

<shrug>So far in 2009 the Arctic extent is certainly lower than the long term mean, yet 2009 has been an improvement over 2007, and April 2009 almost rejoined the mean.

April 2009 sea ice extent may have nearly rejoined the mean, but sea ice mass (extent x thickness) is steadily declining. 2009 is much less than 2008, and it is declining more rapidly than during the same period in 2007.

August 1, 2008

This rapid late season melt is indicative of the thinner ice that is well documented.

http://www.thedailygreen.com/environmental-news/latest/arctic-sea-ice-47011108?src=rss
http://www.nasa.gov/topics/earth/features/arctic_thinice.html
http://www.arctic.noaa.gov/reportcard/seaice.html

 

[sylas]

<shrug>So far in 2009 the Arctic extent is certainly lower than the long term mean, yet 2009 has been an improvement over 2007, and April 2009 almost rejoined the mean.

When you look at individual years, like 2007, or 2009, you have to consider that there's variation from season to season.

The trend, however, is very strong. Even though 2007 was a major outlier, well below what would be expected from the trend; the trend is still sufficiently high that it is a good bet that there will be a new record low within the next few years; and that the Arctic will have a summer essentially free of sea ice sometime within the lifetime of many of the people reading this thread. Probably within my lifetime, if I make it to the age of my parents.

Picking one month (April) is odd.. unless you have some prior reason for singling out April then it looks a bit like cherry picking; it doesn't mean much. One could as well say that as of now, the ice cover is lower than any year on record except the exceptional 2007 season. But that's no assurance at all that 2009 is going to get to second place for the summer minimum of cover. It might, it might not.

And how can you define a "mean"? The mean over what period? Of the last decade? Sure... but since ice cover as been falling steadily for some time now the idea of a "mean" is rather suspect.

Its worth noting that the Arctic is a region that is not representative of the whole planet. The warming in the Arctic is well above global warming, and is substantially a local effect on top the global warming phenomenon. We had a good thread on this recently: [thread=306202]"Only dirty coal can save the Earth"[/thread] (the title is not a good indication of the implications of the study discussed, but the discussion was interesting).

Cheers -- sylas

 

[mheslep]

Certainly the Arctic ice reductions are significant. I was replying only in context to Skyhunter's 'no recovery' comment about '2008, 2009' where April stands out. By 'mean' I was referring to 79-2000 mean depicted in the graphs he posted. I wasn't using April to make any broader comment than that.

 

[Skyhunter]

Certainly the Arctic ice reductions are significant. I was replying only in context to Skyhunter's 'no recovery' comment about '2008, 2009' where April stands out. By 'mean' I was referring to 79-2000 mean depicted in the graphs he posted. I wasn't using April to make any broader comment than that.

My no recovery comment is quite valid and not refuted by your comments or examples. Citing the sea ice maximum extent without the context of sea ice thickness is misleading. The surface is expected to refreeze during NH winter. The large open areas actually increases Arctic temperature because of the release of latent heat during the rapid refreeze. Also the rapid refreeze can have a negative impact on sea ice thickness due to the insulating properties of the snow that accumulates on it's surface.

 

[mheslep]

My no recovery comment is quite valid and not refuted by your comments or examples.

Then don't do it any more. You have several posts up above on extent only.

 

[Skyhunter]

Then don't do it any more. You have several posts up above on extent only.

I don't understand your criticism.

The links I provided dealt with both extent and thickness. If you have a point please state it clearly. Otherwise let's not drag this thread further off topic.

 

[BrianG]

... you can't measure in an experiment is the total effect on Earth's climate. ...
We've not conducted experiments on a planet as such,...

You still get people who deny that a greenhouse effect exists at all, but that is pretty much the young Earth creationism of climate science...
the effect of changing concentrations of greenhouse gases. This means quantifying the effect, in terms of concentrations; and that is not something you can do directly in a lab either... To quantify the effect well enough to infer the effect of changing concentrations on a planet is more difficult...
to actually measure the temperature changes due to changing atmospheric composition can't be done directly. You can't separate out the causes and effects as you can in a lab.
...
A doubling of CO2 concentrations will give a certain amount of additional energy at the surface of the planet... about 3.7 W/m²... You can't measure that number directly...

No matter how large the container, no matter which greenhouse gas, how strong the light source, how long the trial run, you can't experimentally find a temperature change from CO2's greenhouse effect. Is that because it's too small to measure or is climate mitigation inherently untestable, unfalsifiable?

And you think skeptics are like creationists?

 

[Skyhunter]

No matter how large the container, no matter which greenhouse gas, how strong the light source, how long the trial run, you can't experimentally find a temperature change from CO2's greenhouse effect. Is that because it's too small to measure or is climate mitigation inherently untestable, unfalsifiable?

And you think skeptics are like creationists?

The experiments linked in this thread most definitely produce a measurable change in temperature from the radiative properties of CO₂. http://www.espere.de/Unitedkingdom/water/uk_watexpgreenhouse.htm"

If by skeptics you mean climate change deniers... yes, I do think they are like creationists. They ignore the overwhelming evidence because it does not fit their bias.

 

[BrianG]

No, by skeptics I mean folks who question the efficacy of climate change mitigation. Climate change is undeniable, the climate isn't static. If it was, it wouldn't be impossible to isolate a variable like CO2.

Do you really think that experiment is very good? How come it lasts only twenty minutes, there are only five data points for each sample, it tests CO2 at 370ppm and 1,000,000ppm but no other concentrations or other greenhouse gasses and neither the principle researcher or laboratory was identified? Has any other lab reproduced these results?

 

[Skyhunter]

No, by skeptics I mean folks who question the efficacy of climate change mitigation. Climate change is undeniable, the climate isn't static. If it was, it wouldn't be impossible to isolate a variable like CO2.

Do you really think that experiment is very good? How come it lasts only twenty minutes, there are only five data points for each sample, it tests CO2 at 370ppm and 1,000,000ppm but no other concentrations or other greenhouse gasses and neither the principle researcher or laboratory was identified? Has any other lab reproduced these results?

It is not impossible to isolate the radiative effect of CO₂. This experiment does just that.

If you want to deny and reject the evidence that is your perogative. Just remember... the truth does not require your belief, physics doesn't dither, and gravity always wins.

 

[Evo]

Let's refrain from calling names. There are nuts on both sides of the AGW debate, So called "Deniers" are no better or worse than "Alarmists", both cherry pick their data. Stick to discussing facts without getting emotionally involved.

 

[BrianG]

I can experimentally test gravity, how come this unknown researcher at an unknown lab wants this test to remain anonymous? What other labs are doing this work? What does the effect look like with CO2 concentrations at historic levels?

 

[sylas]

I can experimentally test gravity, how come this unknown researcher at an unknown lab wants this test to remain anonymous? What other labs are doing this work? What does the effect look like with CO2 concentrations at historic levels?

I'm assuming good faith here as best I can, but honestly, I have no idea at all what you are talking about.

Of COURSE you can test a basic greenhouse effect. You can't test on a whole planet at once, because it's too big to fit in a lab, but you can test the basic physics of the matter in labs just fine. That's what I tried to explain for you before. It sounds like you are making objections to experiments on a rather curious basis that I am finding hard to follow.

Have you looked at the rest of this thread?

We've been describing a number of experiments that reveal aspects of the problem, including experiments where you get increasing temperature due to the greenhouse effect in a lab setting. The results don't scale linearly to a whole planet; but the physics of the matter is quite straightforward.

A simple test at the level of looking for temperature change is not really all that useful for physics now; it is the kind of experiment used in a school to help children learn more about how science works and get practice doing experiments themselves. It's an experiment where you have to be careful controlling for what you are measuring, but it is entirely doable.

The experiment where you are making speculations about the "researcher" is not actually a "researcher", so much as a simple school level experiment. It's using really basic physics and confirming a result that that is elementary thermodynamics, in no doubt whatsoever for scientists.

The page is actually German, but has been translated for use in schools in the UK. The main topic of the site is water, in fact. Water is also a very important greenhouse gas. The site has a series of simple high school level pages going through some of the properties of water, and includes five pages of "experiments and homework"; the lab test of a CO2 greenhouse effect is one of these.

• The index page is here: http://www.espere.de/Unitedkingdom/ukschoolweluk.html .
• The main page for the "water" unit is here: http://www.espere.de/Unitedkingdom/water/uk_overview.htm . Note that there is a list of contributors given here.
• The experiment proposed is number 5 on the list of experiments and homework. The experiment is described here: http://www.espere.de/Unitedkingdom/water/uk_watexpgreenhouse.htm .

This project was initially carried out in 2001/2002 in Germany, with students aged about 14; though I can't be sure what revisions have taken place since then.

Another greenhouse experiment and worksheet from ESPERE for schools is described here: http://www.atmosphere.mpg.de/enid/4...ion___greenhouse_gases/__Worksheet_2_1gb.html as worksheet 2 in a lower atmosphere unit.

The original of this kind of experiment, in which the effect was first discovered, was conducted in the 1850s by John Tyndall. Those experiments are described in [post=2187943]msg #10[/post] of this thread.

I repeat: this style of experiment is no longer of any great relevance for working scientists. The phenomenon being measured is very elementary physics.

In another thread, I showed an experiment I found with a quick google that is more along the lines of real research: V.G. Arakcheev et al., (2008) Broadening of vibrational spectra of carbon dioxide upon absorption and condensation in nanopores, in Moscow University Physics Bulletin, Vol 63, No 6, Dec 2008. This is not about "greenhouse effect" directly, so much as studying the interactions of radiation and carbon dioxide at genuine research level of experiment. But that is where science is at: the research questions have on.

I am at a complete loss to understand what you meant in this comment in reply to me in another post:

No matter how large the container, no matter which greenhouse gas, how strong the light source, how long the trial run, you can't experimentally find a temperature change from CO2's greenhouse effect. Is that because it's too small to measure or is climate mitigation inherently untestable, unfalsifiable?

And you think skeptics are like creationists?

Um... sure, we do find temperature changes experimentally from CO2 greenhouse effect. Several examples have been given in this thread and I describe some in the post to which you are replying.

As for the creationist remark; I take Evo's point that we want to keep things polite. I was not speaking of individuals here, and I was not speaking of "skeptics" in general.

I was describing three levels of confidence in the details of the greenhouse effect. They are:

• Is there a greenhouse effect at all? That is, does an atmosphere containing greenhouse gases help maintain a warmer surface temperature than otherwise?
• What is the consequence of a CHANGE in greenhouse gas concentrations, and specifically carbon dioxide, in terms of the additional energy available to the surface?
• What is the consequence of the additional energy at the surface in terms of a temperature response?

It was the denial of greenhouse effect at all that I compared with creationism -- point "A" above. I stand by that without hesitation; but it's not meant to be a put down of individuals here; just a clarification of what parts of the question are really really basic... and that IS a relevant point for the physicsforums rules, consistently applied.

As far as physics forums is concerned, I think a consistent application of the rules would mean that this forum is not a place for that level of denial of basic physics. There are some people who will think this is unreasonable or unfair or ignoring scientific criticism; and there's not much point in debating them, frankly. For various reasons this topic is one where public debate does include a lot of really nonsensical physics, but I would hope that the physicsforum mentors are not at that level. I think physics confirmed from over 150 years ago is not what we should be debating here.

The next level of "skepticism" is about quantifying changes in greenhouse gas concentrations. This is at a rather different level; although still actually quite basic and not in credible doubt. On the other hand, the physics now becomes much more subtle, and certainly something that could be usefully explained and discussed in these forums.

The final level is about quantifying a temperature impact, and this is wide open cutting edge science. There are some papers proposing rather extreme outlier values for the effect, but that's the game in science, and I don't have a problem with it.

My main interest here, by the way, is education. I'm not a physicist myself; nor a physics teacher; though I do a bit of tutoring on physics and maths as a sideline. I engage here in topics like cosmology, relativity, climate, because these are topics in which people are genuinely interested and on which there is a lot of public confusion sorting out some matters which are not really matter of confusion in the mainstream of science. That's where I get interested; in topics where there is a disconnect between working science, and public perceptions or policy.

Cheers -- sylas

 

[BrianG]

Sorry, I thought this forum was about experimental tests of CO2's effect on temperature when exposed to IR.

Bye.

 

[sylas]

Sorry, I thought this forum was about experimental tests of CO2's effect on temperature when exposed to IR.

Bye.

Well... that clarifies what is going on, and answers my confusion.

You've been given several examples of precisely that here in the thread; and they are linked in the post to which you reply. I do assume good faith as long as possible, and will continue to assume that for other readers. But not beyond reason, and not for you. You've established that you are not even trying to be sensible, and are just refusing to even read what is right in front of your nose.

Bye. Sylas

 

[cleanwater]

Repeating what I've been saying "The greenhouse gas effect" is a fairy -tale There is no scientific proof that it exists.
The experiment that claims to prove the ghg Effect is junk. below are a list of thing that are questionable or wrong with the experiment and the results.
1. Are the two containers the same size, shape and type of glass? Different types of glass
absorb different wave lengths of IR and heat up differently.
2. Where are the thermometers located relative to the light? Are they in the light path
were they would absorb some of the IR thus skewing the data.
3. If the greenhouse gas effect exists there should be a different temperature of the black
cardboard in the CO2 container. The temperature was not measured therefore this
experiment only illustrates that the CO2 heats up. Does it heat from absorption or from
conduction of different heating of the container?
4. Was the experiment done with other “greenhouse gases?” as CH4 butane, natural
cooking gas, Nitrogen trifluoride ?
5. Did the experimenters reverse the gases to the other container to evaluate differences
in the set-up.?
6. Was more than one set of test done? Is there more data to evaluate?
7. Did you monitor the temperature of the water in the trays? If the trays are in contact
with the gases there is conduction of heat from the bottom of the glass trays to the gases.
8. I can not be sure from the photos but it appears that the top of C1 container is closed ,if
this is true then you have created a confined space heating container (greenhouse effect).
It has been proved by R.W. Wood and others that the heating in a greenhouse is caused
by the restriction of heat convection and not back radiation of IR. The top of C2 appears
open thus keeping the temperature lower by convection. Good job of cheating..
9. What you have shown is what has been known from IR spectroscopes that different
gases absorb different wave lengths of IR but in accordance to Niels Bohr that absorption of IR does not cause the gas to heat up
10. I have done a similar experiment except I used clear Mylar balloons (very little or no
absorption of IR as opposed to glass) Based on IR thermometer reading and available
data on IR absorption by glass much of the heating in the experiment was from the glass.
This was not measured in the experiment. By using Mylar balloons in bright sunlight
there was no heating of the gases inside 4 balloons above ambient temperature (measured
with an IR thermometer reading to O.1 degrees F. The contents were 100% CO2, 100%
butane, natural gas (CH4 and CO2) and air. The black cardboard I used did not show any
differential heating between areas in the “shadow” of the balloons compared to “unshadowed”
areas –no back radiation from the “greenhouse gas effect” The black
cardboard did increase in temperature from ambient of 95 degree F to 175 degree F.
uniformly across the surface.
11. If the greenhouse gas effect exist why hasn’t it been applied to something useful like
thermopane window filled with a “greenhouse gas” that would back radiate IR into the
house and create insulated windows with R=30 values.
You ask the question “Why can it be warmer at night than during the day? Any
elementary school students that can read a weather report know that daily temperature are
effected by hot or cold air masses moving across the area. It is also obvious that
on a clear night the temperature will cool down much faster that on a cloudy night. Water
is not a greenhouse gas in spite of what many people say- it has known properties that
explain temperature differences 24/7/365. There is no back radiation –there is reflection
of light or blockage of light(clouds) energy release as lightning and other thermo effects
that are within the Laws of physics and thermodynamic.
When you find reliable experimental data that proves that the “greenhouse gas effect
exists please share it with the world.
In the mean time read “Falsification of the Atmospheric CO2 greenhouse effects within
the frame of Physics” by Gerhard Gerlich and Ralf D. Tscheuschner and when you
understand it in five or ten years( a PhD level –way above your level of intelligence) and
the global temperature has dropped by the 0.6 degrees that it has gone up over the passed
120year you will realize that man-made global warming is a hoax.
Posted by: cleanwater | May 14, 2009 3:09 PM
Below are the intro and abstract to very relevant technical papers.

Greenhouse Gas Hypothesis Violates Fundamentals of Physics*
by Dipl.-Ing. Heinz Thieme*
*
Deutsche Version siehe:*http://freenet-homepage.de/klima/index.htm
*
The relationship between so-called greenhouse gases and atmospheric temperature is not yet well understood.* So far, climatologists have hardly participated in serious scientific discussion of the basic energetic mechanisms of the atmosphere.* Some of them, however, appear to be starting to realize that their greenhouse paradigm is fundamentally flawed, and already preparing to withdraw their theories about the climatic effects of CO2 and other trace gases.
At present, the climatological profession is chiefly engaged in promoting the restriction of CO2 emissions as a means of limiting atmospheric warming.* But at the same time, they admit that the greenhouse effect - i.e. the influence of so-called greenhouse gases on near-surface temperature - is not yet absolutely proven (Grassl et al., see: http--www.dmg-ev.de-gesellschaft-aktivitaeten-pdf-treibhauseffekt.pdf ).* In other words, there is as yet no incontrovertible proof either of the greenhouse effect, or its connection with alleged global warming.
This is no surprise, because in fact there is no such thing as the greenhouse effect: it is an impossibility.* The statement that so-called greenhouse gases, especially CO2, contribute to near-surface atmospheric warming is in glaring contradiction to well-known physical laws relating to gas and vapour, as well as to general caloric theory.
The full paper is available on line.

Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics
Version 1.0 (July 7, 2007)
Gerhard Gerlich &
Ralf D. Tscheuschner
Abstract
The atmospheric greenhouse effect, an idea that authors trace back to the traditional
works of Fourier 1824, Tyndall 1861 and Arrhenius 1896 and is still supported in global
climatology essentially describes a fictitious mechanism in which a planetary atmosphere acts as a heat pump driven by an environment that is radiatively interacting with but radiatively equilibrated to the atmospheric system. According to the second law of thermodynamics such a planetary machine can never exist. Nevertheless, in almost
all texts of global climatology and in a widespread secondary literature it is taken for
granted that such mechanism is real and stands on a firm scientific foundation. In
this paper the popular conjecture is analyzed and the underlying physical principles are
clarified. By showing that (a) there are no common physical laws between the warming
phenomenon in glass houses and the fictitious atmospheric greenhouse effects, (b) there are no calculations to determine an average surface temperature of a planet, (c) the frequently mentioned difference of 33 _C is a meaningless number calculated wrongly,(d) the formulas of cavity radiation are used inappropriately, (e) the assumption of a radiatively balance is unphysical, (f) thermal conductivity and friction must not be set to zero, the atmospheric greenhouse conjecture is falsified.
The full paper is available on line.
Going back to 1909 -R.W.Wood proved the gh effect as discribed is confined space heating and the ghg effect does not exist.

 

[BrianG]

It's a real shame our educational system has sunk so low, this is the state of our popular science:

 

[sylas]

Repeating what I've been saying "The greenhouse gas effect" is a fairy -tale There is no scientific proof that it exists.
The experiment that claims to prove the ghg Effect is junk. below are a list of thing that are questionable or wrong with the experiment and the results.

No, they aren't questionable issues. You are making up spurious objections asking if the experiments used elementary common sense.

The simple fact that carbon dioxide absorbs thermal radiation much better than ordinary air (mainly Nitrogen and Oxygen) has been known for well over 150 years, and the physics of is now well understood.

11. If the greenhouse gas effect exist why hasn’t it been applied to something useful like
thermopane window filled with a “greenhouse gas” that would back radiate IR into the
house and create insulated windows with R=30 values.

R values are a measure of insulation; which is not the relevant quantity. The relevant quantity here would be the thermal emissivity, with the added requirement that it be transparent to visible light.

Glass is already somewhat opaque to infrared, and treated glass can enhance this effect; which does have some benefits. But it is not the same as insulation quantified with an R-value.

You could get a similar effect with a very strong greenhouse gas like some of the fluorocarbons, but it is more efficient to use treated glass. A window is a bit thinner than the atmosphere. It is idiotic to compare an atmosphere with a thin layer of gas that could be reasonably placed inside a window cavity.

You ask the question “Why can it be warmer at night than during the day? Any
elementary school students that can read a weather report know that daily temperature are
effected by hot or cold air masses moving across the area. It is also obvious that
on a clear night the temperature will cool down much faster that on a cloudy night. Water
is not a greenhouse gas in spite of what many people say- it has known properties that
explain temperature differences 24/7/365. There is no back radiation –there is reflection
of light or blockage of light(clouds) energy release as lightning and other thermo effects
that are within the Laws of physics and thermodynamic.

My actual remarks are in the thread; and I did not say it is warmer at night than in the day. (Good grief!)

Water most certainly is a strong greenhouse gas, and that is a major reason why clear nights are colder.

Atmospheric backradiation is directly measured, and has been for over 50 years. It is very elementary thermodynamics that a warm gas which is opaque to thermal radiation -- like the atmosphere -- will also radiate thermal radiation. An early direct measurement of this is described in Stern, S.C., and F. Schwartzmann, 1954: An Infrared Detector For Measurement Of The Back Radiation From The Sky. J. Atmos. Sci., 11, 121–129. (http://ams.allenpress.com/perlserv/...&issn=1520-0469&volume=011&issue=02&page=0121)

The measurements are made in the night, and in the day. There is a large flux of radiation coming to the surface of the Earth from the atmosphere day and night, though of course the flux is larger in the daytime. It's measured. It's real. And basic thermodynamics means that the atmosphere is emitting radiation; which by Kirchoff's laws means that it also absorbs those same wavelengths.

When you find reliable experimental data that proves that the “greenhouse gas effect
exists please share it with the world.

Done already in the thread. You merely invented a bunch of wholly unfounded objections, which is why people like you are "deniers" rather than "skeptics".

In the mean time read “Falsification of the Atmospheric CO2 greenhouse effects within
the frame of Physics” by Gerhard Gerlich and Ralf D. Tscheuschner and when you
understand it in five or ten years( a PhD level –way above your level of intelligence) and
the global temperature has dropped by the 0.6 degrees that it has gone up over the passed
120year you will realize that man-made global warming is a hoax.

Actually, I have a PhD already, thanks. The main benefit of that is that you appreciate just how facile it is to argue by credentials. An argument stands or falls on its intrinsic merits. The paper by Gerlich and Tscheuschner is one of the worst failures of peer review I have ever seen in a physics journal. It is gross pseudoscience.

In fact, the paper was published without the normal peer review processes normally used in the journal. I sent a message to the journal advising them of its errors after it came out, on my own behalf. It was suggested I reply formally to the journal. I have since done so, as a co-author of a reply that has been submitted to the same journal pointing out some of the many errors; but in my view this should not have been necessary. There's no need to refute the paper for people who know basic atmospheric thermodynamics; the main problem is the failure of the journal editors to pick up such arrant nonsense before publication.

Going back to 1909 -R.W.Wood proved the gh effect as discribed is confined space heating and the ghg effect does not exist.

Wood explained the mechanisms of a glasshouse. He shows, correctly, that it works mainly by limiting convection; not by trapping infrared radiation. That is, he showed that a glasshouse does not work in the same way as an atmosphere opaque to infrared radiation.

This is basic stuff from the first lecture in an introductory course on atmospheric physics. To treat Wood's work as a refutation of the atmospheric greenhouse in the atmosphere is bizarre.

Sylas

 

[negitron]

Water most certainly is a strong greenhouse gas, and that is a major reason why clear nights are colder.

Eh, I have to disagree with the underlined portion (and only with that; I agree with the thesis statement). Cloud cover is an excellent reflector of IR; this works in both directions, obviously. At night, with little incoming energy, the ground and everything on it radiates its usual blackbody spectrum, peaking in the IR. On clear nights, this IR just mostly passes through the atmosphere, with a small portion being absorbed and re-radiated by various atmospheric gases--nothing special here. However, on cloudy nights, the ground-radiated IR is largely reflected from the cloud bottoms back down to the ground where a percentage of it is subsequently re-absorbed; the warmer ground heats the air above it and, voila, you've got a warmer-than-expected night. No greenhouse property of water vapor (which I agree is a real effect, don't get me wrong) is required.

 

[sylas]

Eh, I have to disagree with the underlined portion (and only with that; I agree with the thesis statement). Cloud cover is an excellent reflector of IR; this works in both directions, obviously. At night, with little incoming energy, the ground and everything on it radiates its usual blackbody spectrum, peaking in the IR. On clear nights, this IR just mostly passes through the atmosphere, with a small portion being absorbed and re-radiated by various atmospheric gases--nothing special here. However, on cloudy nights, the ground-radiated IR is largely reflected from the cloud bottoms back down to the ground where a percentage of it is subsequently re-absorbed; the warmer ground heats the air above it and, voila, you've got a warmer-than-expected night. No greenhouse property of water vapor (which I agree is a real effect, don't get me wrong) is required.

My understanding is that the effect you are describing is not "reflection", but absorption and re-emission of radiation... and that is a greenhouse effect. Clouds are good at this because they are made of water.

But I'll check a bit further.

Thanks -- sylas

 

[Skyhunter]

Cleanwater,

Reposting the same cut and paste over and over again is spamming.

https://www.physicsforums.com/showpost.php?p=2285824&postcount=17"

 

[negitron]

My understanding is that the effect you are describing is not "reflection", but absorption and re-emission of radiation...

That's what reflection is thought to be, at a fundamental level. However, clouds are not water vapor, but liquid water droplets. These are MUCH better at reflecting light, including IR, than water vapor (or any transparent gas, for that matter).

 

[chriscolose]

Actually reflection is a much different process, and sylas is right that it is not an important term for Earth's clouds (in the IR, obviously this not apply in the visible). In a lot of planetary applications though (like early Mars, Venus) scattering of IR light is very important. And water vapor or clouds are both very important considerations, whether it be day or night.

 

[negitron]

Actually reflection is a much different process, and sylas is right that it is not an important term for Earth's clouds (in the IR, obviously this not apply in the visible)

I don't believe this is correct. See the following chart: