Arguments
Throwing Stones at the Greenhouse Effect
Posted on 18 October 2010 by gpwayne
Some climate change skeptics dispute the so-called ‘greenhouse effect’, which keeps the surface temperature of the Earth approximately 30 degrees C warmer than it would be if there were no greenhouse gases in the atmosphere. In other words, without the greenhouse effect, the Earth would be largely uninhabitable.
How do we know for sure this effect is real? The principle is demonstrated through basic physics, because a bare rock orbiting the sun at the distance of the Earth should be far colder than the Earth actually is. The explanation for this observation was based on the work of John Tyndall, who discovered in 1859 that several gases, including carbon dioxide and water vapour, could trap heat. This was the first evidence for what we know now as greenhouse gases. Then, towards the end of the same century, a Swedish scientist named Svante Arrhenius proved the relationship between greenhouse gas concentrations and surface temperatures.
Empirical Evidence for the Greenhouse Effect
We only have to look to our moon for evidence of what the Earth might be like without an atmosphere that sustained the greenhouse effect. While the moon’s surface reaches 130 degrees C in direct sunlight at the equator (266 degrees F), when the sun ‘goes down’ on the moon, the temperature drops almost immediately, and plunges in several hours down to minus 110 degrees C (-166F).
Since the moon is virtually the same distance from the sun as we are, it is reasonable to ask why at night the Earth doesn’t get as cold as the moon. The answer is that, unlike the Earth, the moon has no water vapour or other greenhouse gases, because of course it has no atmosphere at all. Without our protective atmosphere and the greenhouse effect, the Earth would be as barren as our lifeless moon; without the heat trapped overnight in the atmosphere (and in the ground and oceans) our nights would be so cold that few plants or animals could survive even a single one.
The most conclusive evidence for the greenhouse effect – and the role CO2 plays – can be seen in data from the surface and from satellites. By comparing the Sun’s heat reaching the Earth with the heat leaving it, we can see that less long-wave radiation (heat) is leaving than arriving (and since the 1970s, that less and less radiation is leaving the Earth, as CO2 and equivalents build up). Since all radiation is measured by its wavelength, we can also see that the radiation being trapped in the atmosphere is at the same wavelengths as those absorbed by greenhouse gases.
Disputing that the greenhouse effect is real is to attempt to discredit centuries of science, laws of physics and direct observation. Without the greenhouse effect, we would not even be here to argue about it.
This post is the Basic Version (written by Graham Wayne) of the skeptic argument "The greenhouse effect has been falsified". It's worth bringing up that the Intermediate Version was written by Chris Ho-Stuart, co-author of the peer-reviewed paper Comment on "Falsification of the atmospheric CO2 Greenhouse Effects within the frame of physics" (Halpern et al 2010).
Some even seem to think that they are more intelligent than anyone else and are able to discard scientific proof because they know the 'true facts' - as opposed to the facts produced by 'elitist' scientists who are only out to enrich themselves and help governments enslave us all, apparently.
The reality is, of course, that such people - deniers of any science they don't like, not just AGW - are arrogant, self-deluding and blind to reality.
But that's not all. What are the other 25% of non deniers doing? Mostly a lot of lip service and hand waving? Are we really changing our lifestyles, or could we even if we tried? What significant changes and sacrifices are we making to lead the way? 350.org is a great concept, but it barely scratches the surface. The world will need thousands of proactive groups like 350.org if we are to overcome the momentum of life as it is.
It is the importance that CO2 plays in the greenhouse effect that we disagree about. The total greenhouse effect includes all energy going into the atmosphere. Convection and evaporation also play an important role in transferring energy into the atmosphere.
I will gladly mock anyone that says the atmosphere doesn't insulate the Earth and keep it warmer. However, this article is inaccurate as I am not aware of anyone claiming that the atmosphere doesn't have an effect.
This article seems intentionally written to insult people that disagree with the theory that the currently increasing CO2 is going to significantly alter the Earth's climate. They are separate and independent issues in every way.
What is the heat capacity of the rocks of the moon? Anybody knows??
If not, just do a search on 'thermodynamics' and you'll get more than your fill. Might have been something to try BEFORE accusing the author of making up an "inaccurate" straw man argument that no one really uses.
A quick Google search pulls up 31,000+ pages with people claiming that the greenhouse effect is bunkum because (they claim) it violates the second law of thermodynamics.
I feel insulted by your pretence at feeling insulted.
I apologize for causing you to feel insulted by my feeling insulted. :-D
I suppose that this website would see plenty of claims that the GHE isn't real. I accept the need for articles like as a result.
Three cheers for Calculus!!!
I am a great fan of Skeptical Science's work to present complex scientific concepts in a way that makes those concepts accessible to a wider audience. I steer people to this website often. My thanks to John and all the contributors to this site.
Also, see this paper from Gerlich & Tscheuschner, and this blog post from Roy Spencer.
Since a significant percentage of energy transfer is by radiation, how can one teach energy transfer concepts without introducing the radiant energy concept? Maybe replacing "radiation" by "energy transfer through electromagnetic wave propagation" would be useful. The whole issue is, what happens as different electromagnetic waves propagate through mass. Most of us know what a microwave oven does to water. It's electromagnetic energy excites the H2O molecules and warms them and the food containing them. Other electromagnetic waves are no different. Higher frequency/higher energy ultraviolet waves from the sun have little effect on CO2 molecules, but they do excite most solid and liquid atoms and molecules in the earth. These excited atoms and molecules, in turn, emit lower frequency/lower energy infrared waves that do excite CO2 molecules, causing them and the atmosphere to heat up.
The real issue for debate ought to be, does every CO2 molecule have the same chance of being heated by the outgoing infrared electromagnetic waves? That is, if 10% more CO2 molecules are added to the atmosphere, will 10% more energy be absorbed with a similar change in atmospheric temperature, or will a smaller or larger percentage of energy be absorbed with less or more effect on temperatures? The answer to this question might hinge on the percentage of infrared energy currently being absorbed by CO2. If that percentage is low, then one might expect increasing CO2 levels to have a higher impact on atmospheric temperatures. If that percentage is high, then increasing CO2 levels would likely have a smaller impact on atmospheric temperatures.
I refer to the 'might' in "What the Earth might be like without an atmosphere that sustains the greenhouse effect".
'Might'? Isnt' the whole point of the post that the greenhouse effect has NOT been falsified? Isn't the whole point that there is no serious doubt about it? For this reason, it should read 'would' not 'might.
Look yourselves at how much more vigorous it is with this change (and a minor tense change, too):
"We only have to look to our moon for evidence of what the Earth would be like without an atmosphere that sustains the greenhouse effect. While the moon’s surface reaches 130 degrees C in direct sunlight at the equator (266 degrees F), when the sun ‘goes down’ on the moon, the temperature drops almost immediately, and plunges in several hours down to minus 110 degrees C (-166F). "
It usually takes the form: "You tell us that without the greenhouse effect, Earth would be -18C average temp. But the moon has no atmosphere and is roughly the same distance from the sun. Its temperature varies wildly from extreme cold to extreme heat. Earth would be the same if it had no atmosphere, so the greenhouse effect must be false".
SoD has a long explanation involving averages and heat capacity. Is there a shorter explanation for the non-physics major?
This is not accurate. One needs to compare the sun's and the earth's radiant intensities across their respective spectra. I can imagine the earth as a converter of higher frequency, shorter wavelength solar photons into lower frequency longer wavelength terrestrial photons.
Take comfort in knowing that, outside the US, the proportions are pretty much reversed.
Not all windows let through UV rays. However, since a lot of the radiated energy is transmitted through visible light, your overall point still stands.
JMurphy linked to the section of this site that answers your question, but here it is more explicitly.
Links for 'Greenhouse effect has been falsified'
One of those links is to Jennifer Marohasy's blog where she talks about "fictitious atmospheric greenhouse effects".
"By comparing the Sun’s heat reaching the Earth with the heat leaving it, we can see that less long-wave radiation (heat) is leaving than arriving (and since the 1970s, that less and less radiation is leaving the Earth, as CO2 and equivalents build up). Since all radiation is measured by its wavelength, we can also see that the frequencies being trapped in the atmosphere are the same frequencies absorbed by greenhouse gases."
The climate may never be in perfect equilibrium, And the instrumental record certainly does suggest a build up of energy in the system, but energy in will equal energy out approximately . Energy is not trapped, its path length out of the atmosphere is increased, increasing the amount of energy in the system... Just with the way thats written it sorta comes across as suggesting that proof of the GHE is that less energy leaves than comes in... only during transition to a higher equilibrium is this true, and in something as chaotic as climate, its more a case of on "average".
I dont disagree, equilibrium can and does change, its the first sentence that just reads to me as though its saying proof of the GHE is that less energy leaves than enters the system... The proof is in the amount of energy contained in the system. Im being pedantic, i admit it, but that first sentence is misleading.
During a hot house period, where the average surface T may be 20k, or a glaciation when the surface T maybe around 12k, at equilibrium, the amount of energy leaving the top of the atmosphere will be the same, and equal to the amount of energy entering the system. During transitions between these states there will be an imbalance between incoming and out going, with more leaving than entering during a decline in T, and more entering than leaving during a rise in T.
The difference in the surface T is a result of the amount of energy contained in the system at their respective equilibriums, and is a result in a shift in the amount of energy in the system, but the "quantity" of energy leaving the system, on its own, is not necessarily representative of the energy contained in the system(T o the climate).
The relationship between the amount of CO2 in the atmosphere and the effect it has in terms of direct retention of energy is logarithmic. A fair number of 'skeptics' become aware of this and try to argue that it means that the effects will be minimal. However, it's no secret to anyone who knows anything about the science. Remember, the central prediction is that, with feedbacks included, there will be a roughly 1% change in the earth's absolute temperature with doubling of CO2. That's 3 Kelvin / ~300 Kelvin which in about 1%.
However, this article is inaccurate as I am not aware of anyone claiming that the atmosphere doesn't have an effect.
Logically speaking, your (admitted) ignorance does not and cannot make this article "inaccurate."
"Some climate change skeptics..."
be
"Very few climate change skeptics..."
"Some climate change skeptics dispute the so-called ‘greenhouse effect’, which keeps the surface temperature of the Earth approximately 30 degrees C warmer than it would be if there were no greenhouse gases in the atmosphere."
Hmmm. No water vapor means no clouds. So with an open sky consisting only of N2 and O2 after millions of years of steady sunshine, you are saying that the oceans would remain frozen? No water vapor also means no snow or rain, so the land is now a dry powder as on the Moon. The dry air in contact with the dry land would receive heat via convection and rise and mix. This air has no GHG, so it cannot radiate heat... only accumulate it via convection with the surface, or release it back via convection to cooler locations on the surface. But this convection is limited to only the cooler air that has circulated downward. The hot air would rise and the stratosphere would get warmer and warmer.
All this may sound like nonsense, yet it is no better than the picture you have painted.
It's a bit like the creationists' equally tenuous distinction between "microevolution" and "macroevolution," where the latter is supposedly some ludicrous extrapolation beyond the evidence, rather than the logical consequence of facts that the creationist claims to understand and accept.
Your picture sounds like nonsense because you do not understand the basic science of heat transfer in the atmosphere. Re-read the 200+ posts in the waste heat thread again and see if you can begin to understand it.
In the absence of CO2 the ocean would freeze. Most of the surface heat would be radiated into space without warming the atmosphere. The remainder of the atmosphere is capable of radiating heat, just not as efficiently as CO2. The temperature of the atmosphere would be much lower than it is now.
Just because your picture is nonsense does not mean that gpwaynes picture is also nonsense.
Thanks for the link. I think this response is talking past what was meant in the links you gave. In the links you gave the writer is incorrectly assigning the term greenhouse effect to the so called AGW and not to the total effect of the atmosphere on regulating the temperature on the surface where people live. The OP on this discussion is then taking that incorrect use of the term greenhouse effect very broadly to mean the effect of the entire atmosphere on maintaining surface temperature.
@doug_bostrom
Glad you posted that graph again. It's the global thermostat. The hotter it gets, the less the effect of CO2. The colder it gets, the stronger the greenhouse effect.
@Phila
Interesting you bring up Creationists. They also believe in global warming. Read Genesis 9:13.
@Phila
Interesting you bring up Creationists. They also believe in global warming. Read Genesis 9:13.
You've managed to cram a surprising number of logical errors into a very brief comment. First, the Bible is not a reliable guide to what "creationists" believe, since different creationists interpret it in very different ways. Second, Genesis 9:13 has nothing to do with climate science, obviously. Third, modern creationists -- of the activist type, especially -- have had a pretty strong tendency to deny AGW.
Perhaps you're taking a stab at the tired old "AGW is a religion" pseudo-argument. If so, this is an exceptionally incoherent version of it. If not, it's hard to see what your point is, or how it's relevant.
Too bad we don't have a dedicated post on this topic to properly discuss it.
The Yooper
"In the absence of CO2 the ocean would freeze."
Now you are saying CO2 is necessary for life. Can you make up you mind? Not to long ago you were telling me it was pollution.
If you want to discuss the matter of CO2 as a pollutant, try "Carbon Dioxide - Everyone's Favorite Pollutant"
All kinds of things are necessary for life, but become pollution if there's too much of it, or in the wrong place. Ozone comes to mind.
"Most of the surface heat would be radiated into space without warming the atmosphere."
What about convection? Can the atmosphere not pick up a little heat this way. And afterwards, without any "green house gas", it would be interesting to know how exactly it should emit heat???
Now you're playing games. You know very well that Michael is entirely consistent. YOU are the one who keeps changing his argument in an attempt to score points. Some CO2 is helpful, too much CO2 is detrimental. Comments like your last do not contribute to the conversation and appear intended to annoy.
"This line of reasoning would be more appropriately discussed on the waste heat thread."
This is not about waste heat. I am talking about solar energy heating the Earth, and that portion of heat entering the atmosphere via convection. This mechanism has been around since creation, and if there were no GHGs, it is hard to see exactly how this heat would be released by the atmosphere as hot air rises. The fact that CO2 and water vapor emit energy as easily as they absorb energy is rarely mentioned.
What a surprising remark, really quite remarkable, even stunning.
Somehow RSVP has failed to note that this entire site, hundreds of others like it regardless of stance, the IPCC and indeed vast amounts of research conducted by a large army of scientists all hinge precisely on the notion that CO2 and water vapor absorb and emit energy. Here we have the notable phenomenon of a person who visits this site nearly daily, is not the slightest bit shy about making assertions, but now says this matter of absorption and emission of energy by CO2 and water vapor is "rarely mentioned." Apparently, during all this time and through endless comments RSVP has not even understood what the fundamental discussion is about, as is I suppose hinted at by his remark above.
This is something ive also pondered... but its one o those things that is dependent on the exact makeup of the hypothetical atmosphere... If we just strip out the persistent ghg and assume all others stop absorbing and emitting(so no O3 creation through UV and water vapor no longer interacts with long wave) The amount of energy reaching the surface would increase substantially, due to the UV and NO CLOUDS... Now, the Q is, as the surface interacts with SW, water vapor will still convect, and there will be convection through conduction with the surface, there will be no way for the energy to escape, and over time i would imagine it would lead to a relatively homogeneous atmosphere.(im not even going to try and think about adiabatic compression possibilities, driven by latitudinal T differentials etc)
The energy transfer being through conduction would mean it couldnt get above the maximum surface T... but thats the max, not the average, it would conduct back down to the surface when it was colder than the atmosphere, so it would probably end up with a stratified profile at night, but moderate energy loss, although no where near like radiation does, with convection working against conduction back down to the surface....
This is headache material... i dont know...
All matter above 0 degrees K emits thermal radiation. The atmosphere will continue emitting radiation into space whether GHG's are there or not. You are tying yourself in knots imagining unphysical scenarios, please stop.
Jennifer Marohasy - In Summary Pardon any confusion from me not clarifying that her scientific expertise and the breadth of her experience do not validate her claims. The purpose of presenting it was to show that she isn't just some random incompetent tapping out blog entries.
HR,
Arguing semantics does not further a discussion. I am also curious to see any empirical evidence for using the more precise terminology.
TOP,
Yes, Dr. Marohasy was explicitly denying the existence of any greenhouse effect that keeps the planet's surface ~30°C warmer, not just "so called AGW". The topic of this page was responding to that specific claim.
What relevance does
have to global warming, much less to a discussion about the greenhouse effect? Did you just type "clouds" into a bible search engine & post the first entry it returned?
RSVP,
"The dosage makes it either a poison or a remedy." - Philipus Aureolus Paracelsus
This concept has been repeatedly hashed out in every relevant page on this site, such as Carbon Dioxide - Everyone's Favorite Pollutant. Please respect the moderation of this site and discuss this over there.
Solar energy does not enter the atmosphere through convection. Convection is the movement of molecules within fluids. In the realm of thermodynamics, it is heat transfer through the movement of molecules within fluids. Solar energy enters the atmosphere through radiation, is absorbed by the planet and radiated in a different wavelength band that is more readily moved in the atmosphere through convection. Heat leaves the atmosphere in the exact same method, with or without greenhouse gases, through radiation.
The fact that water is wet is also rarely mentioned.