Spencer: Earth sans greenhouse effect – what would it be like?

“Invariant (13:56:45) :
What would we talk about without the weather?”
Somebody would invent a catastrophic scenario that can only be averted by giving said person lots of gold so said person can go and try to figure out ways to avert it. Each time said person comes back said person tells the people “It’s even worse than i thought and i need some more gold to do more research.”

“Why would this occur? Infrared absorbers like water vapor and carbon dioxide provide an additional heating mechanism for the atmosphere. But at least as important is the fact that, since infrared absorbers are also infrared emitters, the presence of greenhouse gases allow the atmosphere — not just the surface — to cool to outer space.”
You don’t need the greenhouse gases to cool the atmosphere, oxygen and nitrogen are infared emitters according to the Planck black body radiation effect.
So the atmosphere cools without the greehouse gases.
thanks

Thank you Dr. Spencer, as always you clear the air –so to speak. O/T: Given your replacement’s emphesis on AGW, what’s he really trying to limit? Is there one manmade greenhouse gas that Hansen has some special hatred for? I know from personal experience that the upper atmosphere is full of manmade chemicals that nature never intended to be there. What’s the most offending? Is that Hansen’s demon too?

Dear Dr. Roy W. Spencer,
In this imagined world without greenhouse gases – how long would it take to establish equilibrium again if the world was cooled by 1 ºC?
Best Regards,
Invariant

It’s really nice to see someone of stature putting out this information.
One assumption though was that clouds were not a part of the ‘what if’ scenario. Of course they wouldn’t exist with no water vapor but their effect is great anyway. They’re responsible for nearly 0.22 of the overall 0.31 albedo, reducing the total incoming power that must be balanced. Also, they are going to emit in a continuum rather than simply h2o vapor spectral wavelengths. Essentially though, they also provide a lower temperature ‘surface’ much higher above sea level.
My other concern is that in the basics, the lapse rate fundamentals ignores radiative power loss and absorption and assumes adiabatic.
I believe that Roy has stated many times in the past that the water cycle is the most important aspect by far. At the surface, convection, including the latent heat from evaporation, h2o averages roughly around 100 W/m^2 of energy transfer at the surface. By the tropopause, that amount has reduced to effectively 0. This is from a conservation of energy (power) estimate based on a simple one-dimensional model. This helps define our lapse rate value as it has to have conservation of energy (power) on the short term. That’s not to denegrate the advection effect.
One of the factors that has bugged me is that with the increase of ghgs in the atmosphere, that doesn’t increase any visible light coming in which warms the lower oceans. All of the increase in incoming power to the oceans will be IR and have no penetration into the ocean. That suggests the added heat results in more water evaporation which increases the convection and should lead to greater cloud cover which should increase albedo and reduce incoming solar (some concept of Lindzen’s iris effect concept). In no case should that incoming IR result in heating the oceans lower down. Heat doesn’t flow from cold to warm and all physical phenomenon is working against heating the water from the top.

Aagh, let me try again. Surely the oceans would have convective effects even in your model sans water vapour?

John A

Unfortunately the notion that the lower atmosphere “warms” the surface is physically wrong – no more than double glazing “warms” the inside of a house

If you have to be pedantic, yes.
In reality, the lower atmosphere slows down the rate at which the surface loses heat, thereby making it ‘warmer’ than it would otherwise have been.

If the atmosphere would be without any GHG would it be heated and cooled only from the earth surface. That would result in that the atmosphere over time would be heated close to the earths maximum day temperature. NOT the average temperature. Observe that is the maximum temperature not the average maximum temperature.
Warmer air raising, colder air sink. A cooling only from the bottom of the atmosphere is not very efficient an the warmer air will be kept in altitude.
Cold floor at home anyone but still warm at the ceiling?
The lapse rate would of course be working but the “average” atmosphere temperature would be decided from where it is heated.
A greenhouse effect without ANY GHG.
Adding any GHG or cloud will increase radiation = cooling capacity of the atmosphere. Yes, adding radiation capacity to the atmopsher will cool the atmosphere.
This is precisly the opposite from general AGW theory.
But in line with Dr spencers theory that cloud is a negative forcing.

I am going to have to call BullSh*t on this!
The major disruption of stable air masses he proposes will still exist. They are still going to be the Lunar declinational tides, that move the heat off of the Equator into the mid latitudes. Unless he also proposes to remove the Moon, and it’s influence from the total equation, as they have done for the forecast models the NWS uses.
The atmosphere of Venus has the sun side thermal expansion, and poleward spiral movement to effect what polar cooling goes on, that discribes what will happen to the Earth, with out the moon, not the CO2 / water vapor he is going on about.
Without removing the Moon’s influence, as well as the GHG’s, there will still be the perturbation of large masses of warmed surface air, moved off of the equator into the mid latitudes, with the attendant Coriolis Effects, added into the momentum, still churning the global circulation.
What these people seem to NOT understand, is that the tidal effects of the Moon, are the major driving mechanism of the Weather. He thinks he is removing the Lunar tidal influences simply by taking away the GHG’s feed backs to the system.
When the overall driving forces that create the global circulation are put into the weather / climate equations in their proper strengths, and interactions we will be able to come up with methods, that will be able to forecast longer terms, (5 to 7 days) than the time it takes for the Moon to go from North to South, or back again.
Quote “Since it is the convective overturning of the atmosphere that causes most of what we recognize as ‘weather’, most weather activity on Earth would stop, too. Atmospheric convective overturning is what causes clouds and rainfall. In the tropics, it occurs in relatively small and strongly overturning thunderstorm-type weather systems.
At higher latitudes, that convection occurs in much larger but more weakly overturning cloud and precipitation systems associated with low pressure areas. /Quote
It is the convective over turning, due to the tidal displacement, that mixes the air having high thermal and moisture differentials, causing the rapid precipitation, that results in the lowered pressure along a front, in proportion to the precipitation rates.
It is the combination of the interplay between the heat retention of the GHG’s and the variation in the cooling effects, of the Lunar declinational tides spreading the heat and moisture off of the Equator, that is the weather short term.
Decade length periods, of climate shifts are due to the 18.6 year Mn long period, of the changes in declinational angle at 27.32 day cycles of culminations, interacting with the synod conjunctions of the outer planets, that produce the patterns, they cannot model, with just the physics of the atmosphere considered.
The response I will get from the mainstream, is that I have it backwards.
For their immense budget, huge payroll, and years of study, they cannot get a consistent 10 to 30 day forecast.
From my work, on less than a total $60,000 budget (of my own funds) over 25 years, I can show ~80% accurate daily forecasts for the next 4 years, I think the proof is in the pudding, so to speak.
http://www.aerology.com/national.aspx
Is where you can find the mentioned daily maps by my method.

Invariant (13:56:45) :
What would we talk about without the weather?
We would be talking about the burglars who stole the weather and tried to pawn it at Copenhagen. Fortunately for us, the hot items cooled substantially and all they could produce was a blinding snowstorm. It went over like a ton of ice off the high-dive at the YMCA And, just like the Titanic, they are still plowing about in the dark and short on the lifeboats.

Here is an interesting paper that claims there is no such thing as “greenhouse effect”:
http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf

Re¨ vigilantfish (14:57:43) :
“Surely the oceans would have convective effects even in you model sans water vapour? How would the variable heating of different land and sea masses affect your model?”
Roy wrote:
So, let’s imagine an extremely cold Earth and atmosphere, without any water vapor, carbon dioxide, methane or any other greenhouse gases – and with no surface water to evaporate and create atmospheric water vapor, either.
Alex

Re; pochas (14:46:12) :
“The lapse rate is maintained by the PVT relationships of air. If you heat an element of air, it will decrease in density. Then, archimedes principle will cause it to rise and cool (adiabatically) until its density again matches that of the surrounding air. Thus, even with a transparent atmosphere the sun will heat the earth, the earth will heat the layer of air next to the earth by conduction, causing it to become buoyant, it will rise, etc, etc, etc.”
I think you will find that for convection to be maintained in the long term you need not just heating from below but cooling from above. It is the cooling from above that is lacking in an IR transparent atmosphere.
Alex

Nice article. The earth, with its eccentric orbit around the sun, its rotation period, the inclination of its axis, the composition of its atmosphere and oceans, its strangely huge moon, its geography, geology and topology, etc., is ideally suited for life as we know it. The more I think about it, the more convinced I am that that there are way too many coincidences for the whole thing to be just a coincidence. Whoever it was that planned all this is obviously much more powerful and intelligent than we are and they will not suffer us to destroy it. And no cockamamie climate hypothesis conjured up by imperfect and dishonest men and women will change that.
Just a thought.

if i had to pick two processes it would be the sun and the ocean. then it gets complicated. to say the least.

We may have long abandoned the bone in the beard, peer-reviewed shamanism of the past but we still seem to be caught in the twin headlights of conceit and consensus group-think when it comes to the “We’re all going to die” mantra!
Today’s Science may turn out, once again, to be yesterdays superstition. Who knows? Without the benefit of a time machine, we’ll never know!
As a small and rather insignificant species of sentients let us keep nibbling away at the margins of Nature that keep us ticking along. Adequate foodstuff, shelter, happiness come to mind!
As for the big stuff e.g. Why does big momma Gaia hate us so much, is it ‘cos we is bad, forget it folks.
Irrespective of how many £3 monthly contributions, to adopt a trilobite(sp?), the most-liberal of dinosaurs once made, they still got wiped out!
The reason that we can still argue, make love and blog is because Natures dice have rolled in our direction thus far.
No amount of taxpayers pennies, cast into the accounts of advertising companies, will make one iota of difference to what happens next.
It does, however, make an enormous change to the fortunes of those companies favoured by our political masters.
I would walk 500 miles and I would walk 500 more, if I truly believed that not driving my car would avert a catastrophe. I just don’t believe that is the case. I also believe that I’m being robbed.

Dr. Spencer,
I have a question speaking of temperatures, radiation and conduction. Not so much convection. In the hot summer, in Oklahoma it gets to be 100+ for usually 10-30 days. Setting in the shade on my patio you can just feel the hot IR radiation off the brown fences, roofs and the patio concrete. Uncomfortable! I recently put an atomizer in the tree at the far edge. This atomizer turns a few gallons per hour to a super fine mist over the patio.
My question, when the atomizer is turned on, there seems to be a marked drop in the temperature you perceive, I mean immediately, before the evaporation of the air and evaporation off the hot concrete has occurred and the air has begun to cool. I have always thought this was related to the absorption of the IR radiation because the mist is between myself and the fences, roofs and concrete. Since I’m sitting in the shade, the visible spectrum is reduced and most radiation would be in the IR portion. Does water vapor then absorb a very large portion? It’s a weird effect. Of coarse, after 10-15 minutes it then feels 85 degrees not 105 but by then the patio is lightly wet and the heat in the concrete has dispersed and the air around has cooled.
Could the immediate drop be strictly IR absorption of the water vapor and droplets? Does water absorption bands absorb that much? Never have been able to pin that down.

While we usually only discuss the greenhouse effect in the context of global warming (that is, the theory that adding more carbon dioxide to the atmosphere will lead to higher temperatures in the lower atmosphere), it turns out that the greenhouse effect has a more fundamental role: there would be no weather on Earth without the greenhouse effect.
…
As Dick Lindzen alluded to back in 1990, while everyone seems to understand that the greenhouse effect warms the Earth’s surface, few people are aware of the fact that weather processes greatly limit that warming. And one very real possibility is that the 1 deg. C direct warming effect of doubling our atmospheric CO2 concentration by late in this century will be mitigated by the cooling effects of weather to a value closer to 0.5 deg. C or so (about 1 deg. F.) This is much less than is being predicted by the UN’s Intergovernmental Panel on Climate Change or by NASA’s James Hansen, who believe that weather changes will amplify, rather than reduce, that warming.”

James Hansen has headed NASA’s Goddard Institute for Space Studies since 1981. Prior to that, his Wikipedia page says that “[a]fter graduate school, Hansen continued his work with radiative transfer models and attempting to understand the Venusian atmosphere. This naturally led to the same computer codes being used to understand the Earth’s atmosphere. He used these codes to study the effects that aerosols and trace gases have on the climate.” This is quite worthy of note.
It seems Hansen’s views of the effects of greenhouse gases on the Earth’s atmosphere may have been influenced by his earlier research interests. (For the benefit of those who may not know, the atmosphere of Venus consist of 96% CO2, and the greenhouse effect makes it the hottest planet in the Solar System.)
One can only speculate whether there would have been any greenhouse gas scare or an AGW movement at all, if the person who headed one of the leading institutions in climate science for 30 years ago wasn’t an expert in the atmosphere of Venus.
Would we have the AGW debate we are having now if Richard Lindzen was the head NASA GISS, instead of James Hansen? And just how Climate Science would have been shaped if Lindzen had the vast resources that Hansen enjoyed for the last 30 years.

Fascinating material, Dr. Spencer, thank goodness for people like you, Dr. Lindzen, and Dr. Pielke to leaven all of the alarmist nonsense, and return common sense to the discussion.
You are all mentioned in a wonderful article in a magazine for young people:
http://www.buffalobeast.com, Pants on Fire (forgive the lewd implication).

Mh no weather without the green house effect , this guys thinks different :
http://freenet-homepage.de/klima/atmoseffect.htm

No water vapor huh? That means no water. Which means no life, so who cares?

“David L. Hagen (16:34:54) :
[…]
The new climate theory of Dr. Ferenc Miskolczi”
Oh. I guess that settles the debate for good, then.

GHG act as a buffer. The IR still ends up in space, and is not trapped, just delayed, like traffic. In the end, everyone gets home in space. The net energy flux of IR is still bottom to top.
Not sure why the upper atmosphere should cool since after a steady state is reached, just as much IR is released to space though the upper atmosphere.
Also the upper troposphere has not warmed even though there is more CO2 to capture outgoing IR. I suppose the density is quite low, so perhaps the GHG effect is minimal there, also because there is little water vapor at that altitude, and H2O is the most important GHG. In the desert, it gets cold in the evening, even with all that CO2, since there is not much humidity.
We have geothermal heat, coriolis forces on wind and ocean currents, moons influence on tides, energy being captured for photosynthesis, changing albedo, heat transport to poles from tropics, latent heat, adiabatic expansion, solar variability, air exchanges with the stratosphere, all of which influence on the weather and climate. Simple models do not work, and computers are not fast enough to handle more complex models .
A 1 deg C temperature rise due to CO2 is a 0.37% temperature rise, yet a doubling of CO2 is only a 0.038% increase in atmosoheric CO2. Thats an order of magnitude difference.
I would love to see an energy or heat content balance broken down by components in the atmosphere , O2, CO2, H20, latent heat, etc by altitude, and the net fluxes upward and downward. I mean, how much heat relative to total atmospheric heat is a result of CO2’s IR absorption at a given moment in time.
The article kind of muddies the water since the real issue is CO2 (and I am am Spencer fan), but it does point out how important H20 is. Just don’t confuse H20’s importance with CO2.

I found this to be a very interesting article (I like Dr. Spencer’s work), although I do not believe the so-called Greenhouse Effect Theory works anything like what I most often see being described. I don’t believe the so-called Greenhouse Effect Theory has the ability to heat anything, but instead slightly inhibits cooling or heat dissipation. I also believe that even the most conservative estimates citing a temperature differential between Greenhouse and non-Greenhouse are grossly over estimated. Meaning, the claims that we are 33C warmer with a Greenhouse Effect than we would be without, is grossly over estimated, and I believe the actual figure would be closer to single digits, if at all. The so-called Greenhouse Effect Theory does nothing more than slow the rate of cooling (inhibiting, or slowing, energy transfer).
– The Plinko Effect Theory –
The way I like to think of it is like this. Imagine for a moment a very stable atmosphere, without any wind or air movement at all. Now, release a ball filled with hydrogen or helium, this representing Infrared Radiation. The ball will swiftly float straight upward, accelerating until it reaches terminal velocity. Now, imagine GHG’s being represented by a matrix of static balls evenly spaced throughout that atmosphere (density of balls representing GHG concentration). Now, release another helium ball (IR). What happens? It bounces back and forth through the static balls (GHG’s), still gaining altitude, never descending, but ping-ponging between the static balls like a plinko-chip game (price is right). Any energy transfer that occurs simply spawns the same mechanism upward. The upward moving balls can never transfer energy downward.
Now, one might say, well the IR ball hit a GHG ball and bounced back down. Well, yes, that is possible, however, remember that there are other GHG balls bellow that the IR ball will likely plink off of and bounce right back up again, continuing its ascension as before.
Now, since our atmosphere is not static, and air can move somewhat upward and downward (vertical mixing), it is possible to get some of the balls moved to a lower altitude for a short period of time, but they will always persist in rising. So, at most, one could expect a very slight rise in the total density of lower altitude balls (very slight, and probably equates to more like 1C or 2C, not 33C). You are never able to increase the density of balls at the surface without first directly increasing the rate at which the surface releases those balls. The heat source is always the surface, and GHG’s can only slow the dissipation, and perhaps ever so slightly increase the density of balls near the surface through the so-called Plinko Effect Theory.
Personally, I believe this is a little more accurate representation of what really happens in our atmosphere than does the so-called Greenhouse Effect Theory.
The Earth is not warm because of GHG’s .. and Venus is not hot because of CO2 .. can’t work that way.
My imagination at work … yikes… 😉

Different approach to the question.
What global climate forces brought on the Holocene? And how did those climate forces settle to maintain the Holocene?
What effect would greater or lesser CO2 have in that context?
If there are no answers to the first two questions, then how can the third question be answered?
Well, it can be answered by a look at the climate record of the Holocene, and so far the answer would be that CO2 has no discernible effect outside of normal variance within the Holocene.
If that’s true, then the forces that shaped and maintain the Holocene are not substantially effected and certainly not overridden by CO2.
The human effect on climate might be real, but it’s not substantial enough to be quantified, and not substantial enough to override the climate forces that maintain the Holocene.

Wow. No greenhouse = no weather? Just ask the Martians where the winds surely do blow. Strange that a scientist from NASA would so mislead. All you skeptics out there: you might not want to use this site as your only education if this post is representative of the state of its science.

“Paul (17:42:38) :
Wow. No greenhouse = no weather? Just ask the Martians where the winds surely do blow.”
They don’t have much precipitation up there or do they? BTW doesn’t Mars has a CO2 rich atmosphere? So there’s surely a greenhouse effect on Mars.
wikipedia about Mars: “The atmosphere on Mars consists of 95% carbon dioxide…”
Here i guess the wikipedia is not wrong….

peter_dtm (14:19:11) :

Given the Coriolis force is enough to spin the water in a small sink (except on the equator) …

The only serious study I have ever seen on this debunked it quite effectively. The researcher started with several ‘sinks’, ie large containers with central drains, and left them for over 30 minutes to ‘settle’. This was the only way to ensure there was no effect from initial movement (which does some debunking already). His results then showed that the number of clockwise and anti-clockwise flows for all tests were statistically equal. I am not certain where he was based, but I am pretty certain in the US.
No idea where he got the research grant from. Probably claimed some future nebulous disaster, or something 😉

John A (14:22:37) :
Roy is talking about the planet Mars.
Unfortunately the notion that the lower atmosphere “warms” the surface is physically wrong – no more than double glazing “warms” the inside of a house
Perhaps phrased incorrectly.
Neither warms the earth or house, but it does change the rate at which the house or earth changes temperature.
Steve

“astonerii (17:51:38) :
[…]
if there was a feedback mechanism for greenhouse effects, it would have already taken the earth to boiled ocean temperatures.”
See my comment above. Think about an echo effect in music: When you have an echo with half the amplitude of the original and add it to the input, you get a limes of 2*input even though the echoing proceeds endlessly. This is not even dampened by a logarithmic function. With GHG’s we have logarithmic dampening of the feedback due to the saturation effects so it very quickly ebbs.
IMHO the IPCC has intentionally overestimated this vastly to make sure there’s a scare story. But a (water vapour) feedback is in principle logical.

This is what makes water such an amazing substance. It cools the Earth’s surface when it evaporates, it warms the upper atmosphere when it re-condenses to form precipitation, it warms the lower atmosphere through the greenhouse effect, and it cools the upper atmosphere by emitting infrared radiation to outer space (also part of the greenhouse effect process). These heating and cooling processes are continuously interacting, with each limiting the influence of the other.

Just some of teh properties. Other properties, that are in fact (or also) essential to life are:
1. The extremely rare property (one of 5 substances, I think?) of the solid being less dense than the liquid. This allows ice to float, thus protecting water creatures (as all were at one time) from dying when air temps get too low, as well as breaking rocks into smaller rocks, and then soil, by getting into cracks and freezing.
2. Its very good abilities as a solvent. As I recall, life as we know it could not exist without this property. I recall alcohol is also a very good solvent, but its toxicity to most known life prevent it from being useful (apart from for entertainment of some higher life forms).
3. high surface tension
4. Heat capacity (evident here)
lots more I cannot recall….
Think more dearly of that humble glass of water next time you drink one, without it, we’d not be here!

“But eventually, the entire atmosphere would reach a constant temperature with height.”
No way Watts. The planet still rotates, so there would still be wind. And with wind blowing across oceans (we have to assume zero evaporation for your hypothetical, but some liquid has to be part of the model) and mountain ranges you get wind patterns that will be random.
The gas giants have no CO2 or H2O, mostly Nitrogen, and they have some ean storms with changing patterns.

I tell a lie. the Coriolis force has been proved to affect draining sinks – but only when left for a week!
http://www.ems.psu.edu/~fraser/Bad/BadCoriolis.html

Is it possible to detect the Earth’s rotation in a draining sink?
Yes, but it is very difficult. Because the Coriolis force is so small, one must go to extraordinary lengths to detect it. But, it has been done. You cannot use an ordinary sink for it lacks the requisite circular symmetry: its oval shape and off-center drain render any results suspect. Those who have succeeded used a smooth pan of about one meter in diameter with a very small hole in the center. A stopper (which could be removed from below so as to not introduce any spurious motion) blocked the hole while the pan was being filled with water. The water was then allowed to sit undisturbed for perhaps a week to let all of the motion die out which was introduced during filling. Then, the stopper was removed (from below). Because the hole was very small, the pan drained slowly indeed. This was necessary, because it takes hours before the tiny Coriolis force could develop sufficient deviation in the draining water for it to produce a circular flow. With these procedures, it was found that the rotation was always cyclonic.

“What if there was no greenhouse effect? In other words, what if there were no infrared absorbers such as water vapor and carbon dioxide in the atmosphere?”
=====================================
Marie Curie quote:
“I am among those who think that science has great beauty. A scientist in his laboratory is not only a technician: he is also a child placed before natural phenomena which impress him like a fairy tale.”
she probably didn’t believe in fairy tales, or “what if’s”

Roy W. Spencer, Ph. D.
I think this post was a bad idea for your ‘street cred’ Roy.
The scenarios you suggest are impossible, even in a ‘thought experiment’. For example:
There is no way that a planet with so much water would ever generate an atmosphere without water vapour (WV), as even ice sublimates. Though, if there were no ‘radiative gasses’ in the atmosphere, the atmosphere would neither radiate, or absorb, radiation more than its natural LTE (local thermodynamic equilibrium) temperature equivalent (again, a most unlikely scenario, given the expected gasses from any ‘planetary surface warming’ of a rotating planet [I exclude satellites, or ‘moons’, as they tend to undergo gravitational loss of atmosphere to their ‘parent’ body]).
Your statement “there would be no weather on Earth without the greenhouse effect.” seems so wrong. Without the temperature ‘hot spot normalisation’ ameliorated by radiative influence, the ‘normalisation’ of temperature ‘hot spots’ is left solely to the ‘thermals’ that cause ‘weather’. So! In a ‘radiative gas-less Earth’, only ‘surface albedo’ rules with its associated level of increased thermal convection! I can’t reconcile this within your scenario Roy. Especially when LTE is disturbed by lack of radiative influence, (this is almost unheard of) as it’s always there where an atmosphere exists.
This is half of what I want to say, but it’s both late for me and should be enough for an initial query.
Best regards, suricat.

Well, what do you know, my grade school science book was right, we do live in a mostly closed loop world. It’s amazing how many lay people believe in AGW, but have no idea that the earth can and does actually have mechanisms to cool as well as warm this place we call home.
Needless to say most of the higher theories that get discussed here just goes right over my head (not a climate scientist), but I’ve noticed that generally when people have AGW discussions, I rarely see much common sense applied to anything. (The reasoning that we are running out of water just dumbfounds me…).
I would assume that the good old-fashioned, well tested physics rules would still apply. I do realize that external inputs will cause all sorts of chaotic I/O, but still…

“suricat (18:53:50) :
[…]
The scenarios you suggest are impossible, even in a ‘thought experiment’. ”
Hmmm… that’s a wild statement.
“There is no way that a planet with so much water would ever generate an atmosphere without water vapour (WV), as even ice sublimates.”
In reality, you would be right. But we are in a thought experiment.
” Though, if there were no ‘radiative gasses’ in the atmosphere, the atmosphere would neither radiate, or absorb, radiation more than its natural LTE (local thermodynamic equilibrium) temperature equivalent (again, a most unlikely scenario,”
In reality, it would not be unlikely, it would be right out. But we are in a thought experiment.
” given the expected gasses from any ‘planetary surface warming’ of a rotating planet [I exclude satellites, or ‘moons’, as they tend to undergo gravitational loss of atmosphere to their ‘parent’ body]).”
Well, let’s just say as much radiation goes out as goes in.
“Your statement “there would be no weather on Earth without the greenhouse effect.” seems so wrong.”
Yes.
” Without the temperature ‘hot spot normalisation’ ameliorated by radiative influence, the ‘normalisation’ of temperature ‘hot spots’ is left solely to the ‘thermals’ that cause ‘weather’. So! In a ‘radiative gas-less Earth’, only ’surface albedo’ rules with its associated level of increased thermal convection! I can’t reconcile this within your scenario Roy. Especially when LTE is disturbed by lack of radiative influence, (this is almost unheard of) as it’s always there where an atmosphere exists.”
Surface albedo affects upward reflexion. The thought experiment says that there are no greenhouse gasses, that means no gasses that stop part of the radiated spectrum of frequencies from leaving the planet. Thus, the reflected or emitted radiation from the surface cannot warm up parts of the atmosphere, thus there would be no radiation-caused temperature differences, so no convection.
My take.

Sounds a bit like Snowball Earth, which required millions of years of CO2 spewing vulcanism to thaw.

wayne (18:51:41) :
Good question about the CO2 and the answer is not so straight forward. Although there are about the same number of molecules of CO2 above any sq meter on Mars as on Earth, they are not nearly as effective as a greenhouse gas because the total atmospheric pressure is much lower. The higher density of gas in Earth’s atmosphere works to spread the absorption of IR by CO2 over more of the wavelength scale. Consider building a fence out of 2×4’s spaced every 8″ (rough cut). 50% of the light hitting the fence from the side will make it through the fence. Alternatively, consider using 1 x 4 spaced every 4″. Same amount of wood, but no light would get through. This is how it works for CO2 (and H2O) on Mars and on Earth. The same amount of CO2 (or H2O) is more efficient on earth because of all the N2 and O2 colliders (this is called pressure broadening. There is a reasonable wiki page http://en.wikipedia.org/wiki/Spectral_line but it could use to be updated to discuss the role of broadening on climate.

Alex Harvey (16:01:44) :
You wrote: “I think you will find that for convection to be maintained in the long term you need not just heating from below but cooling from above. It is the cooling from above that is lacking in an IR transparent atmosphere.”
True enough. In a planet with a transparent atmosphere the “weather” would be driven by heat transport from the equator to the poles, as already mentioned by other posters, giving Mars as an example. Dr. Spencer mentions it as well, although he seems to minimize it.

All right…I’ve got some fodder for weather lectures coming up in a few weeks. Thanks!
I wonder how many parent complaints I’ll get this time?!

Since the moon is about as far away from the sun as earth, and it has no atmosphere, that might be a good place to look for a comparison.
“…the temperature of the Moon can dip down to -153°C during the night. Oh, but you’re going to want to keep some cool weather clothes too, since the temperature of the Moon in the day can rise to 107°C.”
http://www.universetoday.com/guide-to-space/the-moon/temperature-of-the-moon/
So, we see that it is NOT the “greenhouse” effect that “warms” the earth, but that the atmosphere has a cooling effect on daylit surfaces, while the surfaces not lit are kept from losing their heat too fast.

Dr. Spencer;
It’s not a doctoral dissertation; it’s a fine and elemental primer, elegant in its simplicity. I’ve seen the objections in some comments, but I think they miss the point.

So what was earth’s climate like 200,000 years ago, Dr Spencer? Oh, that’s right, God hadn’t created it yet…
http://theevolutioncrisis.org.uk/testimony2.php

Paul (19:34:32) :
wayne (18:51:41) :
Good question about the CO2 and the answer is not so straight forward. Although there are about the same number of molecules of CO2 above any sq meter on Mars as on Earth, they are not nearly as effective as a greenhouse gas because the total atmospheric pressure is much lower.
Yes, and Venus has 90 atmospheres which is where CO2 driving
temperature came from. That, along with the Snowball Earth
hypothesis has been driving this train wreck.

At the risk of making a fool of myself again, I need to explain what I meant when I asked about the effects of oceans. Imagine that there are oceans on this planet, but that they have a layer of impermeable saran wrap on top that prevents evaporation. The differential heating of the oceans and the heat-retentive properties of water would result in air circulation: one does not need to consider the evaporative tendencies of water in this model, in the spirit of Dr. Spencer’ thought experiment. I guess I cannot quite imagine the value of a theoretical model which is so unlike the earth, given the vast amounts of H2O on our planet that play both primary and differing roles (according to state and location) in determining climate. Even without water, does Dr. Spencer’s model assume that the entire substrate of the earth is homogenous, with no hills or elevations or differing properties for absorbing and reflecting heat? As Robert of Ottawa points out above, Dr. Spencer is having fun with a spherical planet.

Frost warning for much of Florida tonight.
per the Weather Channel

John J. (19:24:10) :
No weather without so-called greenhouse gases? Jupiter is mostly hydrogen and helium and yet the Great Red Spot has persisted for centuries.
And how is it possible that the internal temperature of Jupiter with no CO2 is greater than the surface of Venus? I’ve asked this question to a couple of professors at my local university and never gotten a reply.
ShrNfr (19:42:03) :
@John J. Jupiter emits more energy than it receives in solar radiation. One therefore is drawn to the conclusion that there is something going on deep in the core of the planet.
Actually, I heard long ago in college it is simple compression. There is great gravity, it would like to compress all those gas molecules down, and as they are compressed they give off their heat. IIRC Jupiter emits about 1.6 times the energy it gets from the Sun.
And the Great Red Spot is shrinking. There is also now the Little Red Spot, which may grow to be the larger one. Click on the link, read about some Climate Change on Jupiter!

“there would be no weather on Earth without the greenhouse effect.”
OM[snip]G is that a stupid statement. I really wish Spencer would stop trying to help.
Without the greenhouse effect sunlight would still warm the ground. The atmosphere in contact with this ground would be warmed. The equators would still be warmer than the poles, leading to a difference in air pressure. Heated water would still evaporate over the seas lowering air pressure there. That moisture would still condense into rain.
All the effects would cause wind, rain, clouds, snow, and all the other things we call weather.

Inks,
Kick yourself again. The earth isn’t some uniform flat plain. Different surfaces absorb light with differing efficiencies. Light sand absorbing less than dark rock. Water absorbs differently than land. Sides of mountains facing sunward more than those facing away. Equator more than poles. The earth rotates. Many other factors.
“but the atmosphere has no way of cooling”
This is another false claim by Spencer.
Substances can radiate frequencies for which they are transparent. Glass is transparent to red light yet if you heat it enough it will radiate light at that frequency. So the atmosphere without GHG will continue radiate heat to space.
There is absolutely no way that if you eliminated the ability of all gases on earth to act as greenhouse gases that it would eliminate weather. In fact, GHG contribute next to nothing with regards to causing wind, rain, snow, etc.
If all gases were transparent to infrared we could just move the earth closer to the sun to achieve a planet with liquid seas, and plenty of weather.
I think I understand now why Spencer is a creationist. He’s not very good at understanding models and processes.
I’m a AWG skeptic. This article is just bad science.

Brian Macker (23:05:06) :
I’m a AWG skeptic. This article is just bad science.
I agree with you. False scenarios profit no one.

Thank you Dr. Spencer for the some deep insight. I for one can follow your gist and ignore factors obviously occurring in the real world and alter my view in a hypothetical sense to simplify a system down to the core points being discussed. Once again thanks.
Here’s a supplement paper I never had stumbled upon concerning excess radiation absorbance in clear atmosphere and clouds and handled differently in most models of that time. Have no idea if these factors have changed in current day models.
http://people.aero.und.edu/~dong/Valero_JGR_2000.pdf
Interesting. Don’t know if even more massive simultaneous tests have occurred recently. This answered the question I asked you near the top of these comments.

Robert E. Phelan (22:34:35) :
Hmmph. Frost in Florida. The Weather Channel keeps talking about some blizzard in New England. No snow here on the Connecticut Western Shore. Climate: it’s all local.
This cold in Florida was brought up ahead of time here at WUWT on 12/30/09.
http://wattsupwiththat.com/2009/12/30/major-northern-hemisphere-cold-snap-coming/

This is a very good article. I wonder anyone has ever attempted to model or estimate the state of the atmosphere during the ancient period, very similar to Dr. Spenser’s thought experiment, when geological evidence indicates that the earth may have frozen over all the way to the equator. Is it possible that the tropopause descended all the way to the surface in this event?
As it has become fashionable of late to assume carbon dioxide to be the cause of all things related to the greenhouse effect, I now wonder if volcanic CO2 was really the most likely reason for the end of the ice-cube earth period.

I would like to point out here that thermodynamics is a self contained description of nature and works wonderfully well until it hits dimensions of hbar or coherent effects as in superconductivity, superfluidiy etc.
Thermodynamics treats radiation well, and this at a time where nothing was known of infrared absorption bands and dipole molecules and such, all in the realm of quantum mechanics and hbar sizes.
To say that a body of matter will only radiate heat away only if the molecules consisting it have infrared absorption lines is making a total confusion between classical thermodynamics and quantum mechanics, that displays the confusion in the heads of climatologists and I suspect leads to double countings, like that nice oven by Peden, http://www.vermonttiger.com/content/2008/07/nasa-free-energ.html .
I want to remind everybody that the ideal gas is really tiny billiard balls, not heat factories of infrared, and the heat of the ideal gas is the motion of these within it.
The radiation is given by Wien’s law (~1890 before quantum mechanics) http://en.wikipedia.org/wiki/File:Wiens_law.svg and the black body radiation are all classical thermodynamics.
I hope this settles that all things that have temperature radiate.
It is not that there does not exist a statistical quantum mechanical description of what really happens when molecules and photons shake hands. Tom Vogt once gave me a dense precis of what happens and how finally infrared photons absorbed and being held tight by a molecule end up as kinetic motion and heat of the gas . It is not simple, it is not just dipole, it is complicated. BUT all matter radiates according to the laws of classical thermodynamics.

Mike Borgelt (00:05:29) : “The same amount of CO2 (or H2O) is more efficient on earth because of all the N2 and O2 colliders (this is called pressure broadening. …”
What I don’t get is at the point after IR absorption, a CO2 molecule will ‘braoden’ to ANY other molecule, O2, N2 and CO2 molecules also. So I see this as a null statement. Am I wrong?

kuhnkat (16:08:26) :
kuhnkat, thank you for leading me here;
http://climatechange1.wordpress.com/
I have bookmarked it, and will read it again and again. Never
before have I found a more interesting article about what drives the climate.
Finally someone that understand that the most important thing is to understand whether the wheels drive the pistons, or whether the pistons drive the wheels.
The AGW’ers thinks the wheels drives the pistons.

anna v (00:14:54) :
You sound more versed in thermodynamics than myself. Honestly. Please help clarify my view if you know.
Real but somewhat a thought experiment. Take a single molecule in empty space at rest, no momentum. A photon at correct frequency is absorbed by that molecule, knocking an electron a shell higher. I assume that until it drops back the molecule now has momentum. When the electron drops back down, here my big question, seems it must be ejected exactly in the same direction that it was traveling before it was absorbed cancelling the momentum. Is that a correct view? The answer eludes me.
According to your answer, I might have a following question.

Nick Stokes:
” the adiabatic lapse rate of -9.8 K/km? Surely this mechanism moves heat more effectively than conduction?”
By definition, no. Adiabatic implies without exchange of heat.

I have heard personally from Prof. Taro Matsuno (one of the best theoretical meteorologists in Japan) that there has been no simulation in which CO2 concentration is set to be zero. He said that such simulation had to be carried out although researchers had interests only in cases with increased CO2.

Mike Borgelt (01:01:05) :
Well, the thread title is:
Spencer: Earth sans greenhouse effect – what would it be like?
So we’re off thread, but I was trying to point to Venus as the
origin of the AGW runaway greenhouse effect scare. They beat
this drum and always leave out pressure, as part of the equation.
Mars is another good example. The pressure on Mars is 1/100-150th
that of Earth. So I don’t think Mars is in any danger of thermal
runaway or reaching a “Tipping Point”.

wayne (01:08:21) :
anna v (00:14:54) :
You sound more versed in thermodynamics than myself. Honestly. Please help clarify my view if you know.
Real but somewhat a thought experiment. Take a single molecule in empty space at rest, no momentum. A photon at correct frequency is absorbed by that molecule, knocking an electron a shell higher.
Right here we are not talking of thermodynamics, the system you are describing is a quantum mechanical system, where there are potential wells and energy levels. These are nonexistent in thermodynamics.
So lets see the quantum mechanical problem.
I assume that until it drops back the molecule now has momentum.
Energy and momentum have to be conserved: the molecule will acquire some momentum and the photon will kick the molecule up to a higher energy level. A pregnant molecule.
When the electron drops back down, here my big question, seems it must be ejected exactly in the same direction that it was traveling before it was absorbed cancelling the momentum.
No, this is not correct. The decay will have a characteristic time of electromagnetic decays, and the direction will be probabilistic, in a type of antenna like pattern, depending on which state has absorbed the photon. Most often two or three or more, much softer photons come out depending on the energy levels available for the molecule as a whole, contributing to thermalization by the kick back of conserving momentum for each decay.
Again this is the quantum mechanical picture.
To this statistical quantum mechanics has to be applied, behavior of i.e. large numbers, and then one can start comparing the view derived this way to the thermodynamic view.

Moderator please bear a long one.
anna v (02:34:06) :
OK! That’s the key. I know if there are many emission lines, the momentum will be split between the photon(s) of lower wavelength and some residual momentum may reside in the molecule. But conservation of momentum must always be preserved. One place or the other(s).
Please follow. Think only of the original parcel of momentum and keep track of it.
I have read literally a hundreds of papers concerning this broad subject. But I kept having a reoccurring catch in all of the pure logic used. Let’s take this as Einstein would, one infinitesimal thing at a time.
Take a special IR photon, properties set by me, carrying energy thus momentum, leaving a spot on the equator and heading directly zenith to keep this pure.
The momentum carried by this photon, one way or the other must be preserved. The photon may be absorbed by a molecule in proximity if wavelength allows, that molecule hits other molecules so momentum of the molecule changes and is distributed, this can occur many times. But mother nature by her physics is so frugal with her accounting of her energy and her momentum that she will not miss the tiniest portion of her precious energy and momentum.
That momentum from that zenith heading photon may be divided and scattered over many molecules or subdivided into components of other photons in various directions but the SUM of the net effects of that lonely photon’s momentum will end up in portions of two states. One component’s portion (can be zero) escapes into space carried by the original OR divided between some other photon(s) in some direction(s) possibly at different wavelength(s). The other possible state is to cause an infinitesimal but real and exact expansion of Earth’s atmosphere by increased momentum of a molecule(s). This will initially manifest as an increased pressure but eventually will be expansion. The sum of the momentum of these two states (speaking only of the original photons momentum), seems to me MUST be equal to the original momentum of that lone photon to meet conservation laws.
If the above is correct, from here on only speaking of that original parcel of momentum. If the photon didn’t encounter any interaction on its way up, it merely escapes into space. End of story, momentum preserved. However, if it had any interaction and the portion of momentum escaping into space (can be zero) is less than the original, the only other possible state is an expansion of the atmosphere by the remaining portion of the original momentum.
If I’m still right to this point, you can now view that photon’s momentum generically as radiative pressure. And any layer of the atmosphere as a near spherical membrane that this momentum must cross, one way or the other to satisfy conservation of the momentum.
The gist of the above is to say that energy, thus momentum, of outgoing photons cannot be absorbed and re-radiated IN A NADIR direction without also expanding the atmosphere, thus, by thermodynamic laws cooling the atmosphere in an equal amount of the heat trapped.
I’m stuck on this point. Reoccurs in my mind every paper I read and until I can get a understandable answer, I don’t feel an added portion of CO2 that traps additional heat can help but to expand the atmosphere thus cancelling any effect. Some papers support this view but from other directions. I tried to make mine simple.
Any help, corrections or comments?

The last line of my previous post should have read:
We usually think of convection as being forced by heating at the surface, but cooling above is required to keep the process going.

”
Mike Borgelt (23:36:40) :
D. King (21:19:05) :
” Paul (19:34:32) :
wayne (18:51:41) :
Good question about the CO2 and the answer is not so straight forward. Although there are about the same number of molecules of CO2 above any sq meter on Mars as on Earth”
I get about 30 x as many over any square meter on Mars. Would you care to justify your number?
2
01
2010
wayne (23:59:15) :
Mike Borgelt (23:36:40):
Exactly. Paul was saying because the low pressure on Mars, I’m assuming partial pressure, that CO2 on Mars has no effect on temperature or weather at 90% component. I’m questioning why a much lower partial pressure for CO2 on Earth would have any effect either if his statement is correct about
”
Mars has a different diameter and a different mass, hence the gravitational acceleration g is different. It’s atmsophere at the surface is only about 1/100 that of Earth but has 90 to 95% co2. The optical path depends upon the total number of absorbing moleculars of a type in that path. The math will tell you that there is 30 to 40 times the number of molecules of co2 present in the atmosphere of Mars than of Earth. That’s 5 doublings of concentration above and beyond that of Earth. On Earth, a doubling of the molecular count is going to produce an incremental increase of power absorption (in clear skies looking down at an altitude for a straight radiative portion of the problem).
That said, if one looks at the average Martian orbit and its albedo and does a simple incoming radiative calculation for a blackbody and compares it to measured temperatures, one discovers that there is no warming present due to the co2 that is obvious. Whatever exists is basically 0.
The difference being, as mentioned, is that the pressures of both the co2 and other constituents of the air are much lower than lower in Earth’s atmosphere. This is the pressure broadening which smears out the line emissions and absorption likelihoods so that more spectral area is affected. Note that having a high peak and narrow width has little effect compared to a lower peak with greater width when both are pretty much total absorption at the peak after a very small path length.
When one looks at a simple Earth model and accepts h2o in vapor and cloud form being 90% of the ghg effect of 33 degree C rise over a blackbody of similar albedo (0.31), that’s almost 30 degrees C worth and leaves co2 and all the other ghgs a whopping 3 degree C contribution with roughly equal amounts for each time there is a doubling or halving of the total number of a particular molecule’s concentration – as long as that halving doesn’t change so the optical path to extinction becomes large compared to the size of the atmosphere or layers of the atmosphere.
If one looks at clear skies with no clouds, that 90% fraction due to h2o drops significantly and co2 approaches closer to 20% and water closer to 70%, leaving some percentage left for all the other ghg molecules.
Concerning Anna V’s comments, I don’t think you can separate out the radiative thermo from the advent of the quantum mechanics as this is where the classical broke down. Planck’s radiation law introduces that insidious little constant, h, although it is still thought of as being in the classical realm. The blackbody continuum exists for all matter in liquid and solid states (at least sorta). There one has all sorts of interactions between molecules that allow for quantum states ad naseum. Clouds and particulates provide tiny bits of liquids and solids that are no longer limited to only atomic or molecular spectrums but as they get smaller in size, one may not maintain a true BB spectrum – which actually describes the Boltzman distribution or likelihood for atoms and molecules being in a given energy state at a given temperature. If one applies this distribution to the absorption spectra of a molecule, one gets the emission spectra.
With gases that aren’t hot, one has the pressure broadening and a doppler shift broadening associated with temperature. The Sun’s photosphere, compared to Earth’s surface, a moderately decent vacuum at 6000k produces pretty much a BB continuum for that temperature as mostly hydrogen gas wells up rather hot and dumps its radiative load cooling down and returning below that thin “surface” or few kilometers of radiative area.
Cool hydrogen gas is not going to radiate like that. You’ve got the 21cm line based upon flipping spin states but basically, nothing in the visible or IR. In order for the hydrogen to emit in the visible, it must be raised to higher energy states as the electron dropping to the lowest energy state is going to emit in the uV. That’s why (hydrogen alpha) pink hydrogen emitting nebulae exist only where there are bright uV emitting stars nearby. IR (and microwave) tend to depend upon molecular vibrations and rotation modes, unless the atoms or molecules are heated sufficiently to get above the lower energy states.
Just like the qm and classical, while I like Dr. Roy’s presentation and simplifications as an explation, it does have its problems and I’m not sure just how much one can keep that simplified and come conceptually close to describing the system. As for affecting the weather with no ghgs, it certainly would have serious effects. Not having h2o vapor would have serious impacts on the pressure differentials and hence the circulation as well as about everything else from albedo to convection.
If one were simply to drop all but h2o, it’d hardly be noticed, just a few degrees. Maybe that would be enough to trigger an iceage or snowball Earth and then again, maybe it would not without massive extra forcings.

wayne (03:13:52)
That seems plausible but operates counter to the general wisdom that an expansion of the atmosphere may occur but that such an expanded atmosphere is at a higher temperature due to a new equilibrium having been set by the increased length of time the solar energy remains in the Earth system before it is released back to space.
So, one might have an expanded atmosphere but with a higher total energy content than before so a higher temperature will be recorded. You would only see cooling from expansion if the total energy content remained as before but in fact it doesn’t because the increase in the time taken for energy to negotiate the system means that there is more energy in the system to show a higher temperature notwithstanding the expansion.
I hope that makes sense.

John J. (19:24:10) :
No weather without so-called greenhouse gases? Jupiter is mostly hydrogen and helium and yet the Great Red Spot has persisted for centuries.
And how is it possible that the internal temperature of Jupiter with no CO2 is greater than the surface of Venus? I’ve asked this question to a couple of professors at my local university and never gotten a reply.

Change your university. Jupiter has minute traces of rock dust, methane and water. In the terrific mass and pressure of Jupiter’s atmosphere, even a minute trace amounts to a huge amount. You may have noticed that Jupiter’s atmosphere is not transparent. It absorbs radiation and therefore also emits it. The planet’s core is about 20,000C, three times hotter than Earth’s. Without wanting to divert a year or two to study the physical processes in Jupiter’s atmosphere, it is nevertheless clear that you haven’t got a professor-stumping question there.

wayne (03:13:52) :

Moderator please bear a long one.
anna v (02:34:06) :
OK! That’s the key. I know if there are many emission lines, the momentum will be split between the photon(s) of lower wavelength and some residual momentum may reside in the molecule. But conservation of momentum must always be preserved. One place or the other(s).
Please follow. Think only of the original parcel of momentum and keep track of it.
Conservation of momentum is not the same as conservation of energy, in that momentum is a vector and can add up to 0.
We are in the quantum mechanical framework: once the photon is absorbed, the momentum conservation is taken up by the molecule and it is riding happily away at a constant velocity, until it interacts with another molecule or force. Conservation of energy from the same interaction says that there is potential energy in the molecule, the energy left over from the one that became kinetic to conserve momentum.
Take a special IR photon, properties set by me, carrying energy thus momentum, leaving a spot on the equator and heading directly zenith to keep this pure.
The momentum carried by this photon, one way or the other must be preserved. The photon may be absorbed by a molecule in proximity if wavelength allows, that molecule hits other molecules so momentum of the molecule changes and is distributed, this can occur many times. But mother nature by her physics is so frugal with her accounting of her energy and her momentum that she will not miss the tiniest portion of her precious energy and momentum.
That momentum from that zenith heading photon may be divided and scattered over many molecules or subdivided into components of other photons in various directions but the SUM of the net effects of that lonely photon’s momentum will end up in portions of two states. One component’s portion (can be zero) escapes into space carried by the original OR divided between some other photon(s) in some direction(s) possibly at different wavelength(s). The other possible state is to cause an infinitesimal but real and exact expansion of Earth’s atmosphere by increased momentum of a molecule(s). This will initially manifest as an increased pressure but eventually will be expansion.
See, this is what I mean about mixing up systems. Pressure is a thermodynamic variable, entering into the PV=RT formula. In the quantum mechanical frame the excess momentum of one or n molecules will become excess kinetic energy which after millions of similar interactions will appear in the quantum statistical formula which eventually at the limit will manifest as temperature and pressure in the medium, gas in this case.
The sum of the momentum of these two states (speaking only of the original photons momentum), seems to me MUST be equal to the original momentum of that lone photon to meet conservation laws.
No. Once a photon has been absorbed by raising the energy level, rotational vibrational or whatnot, of the molecule, it disappears. Photons are not conserved, there is no photon conservation number. Lets keep it simple , one photon hits one molecule and is absorbed, and the molecule gets a kick in the direction of motion of the photon. The deexcitation of the molecule, suppose it happens with one photon for simplicity, will introduce a new conservation of momentum. The molecule will go one way and the photon the other, but the direction will have no connection with the original photon’s direction. It will be random in direction within a probability distribution given by the state it occupies, and the molecule will kick in the opposite direction. The original momentum conservation law was satisfied by the increased velocity of the molecule that originally absorbed it. After deexcitation,the molecule will have the vector sum of the original momentum plus the opposite momentum to the exiting photon.
If the above is correct, from here on only speaking of that original parcel of momentum.
Well, it is not.
If the photon didn’t encounter any interaction on its way up, it merely escapes into space. End of story, momentum preserved. However, if it had any interaction and the portion of momentum escaping into space (can be zero) is less than the original, the only other possible state is an expansion of the atmosphere by the remaining portion of the original momentum.
Once again, expansion and atmosphere are macroscopic thermodynamic concepts and variables. In this large thermodynamic collective, the increase in the average velocity of molecules manifests as temperature and is connected to pressure through PV=RT in gases.
If I’m still right to this point, you can now view that photon’s momentum generically as radiative pressure. And any layer of the atmosphere as a near spherical membrane that this momentum must cross, one way or the other to satisfy conservation of the momentum.
You are ignoring the fact that infrared photons coming from the ground up are neither coherent nor unidirectional, particularly as the surface of the earth is fractal, though one could see a radiation front forming, if there were no atmosphere, which could be described as having radiation pressure, I do not see what conservation of momentum has to do with it.
The gist of the above is to say that energy, thus momentum, of outgoing photons cannot be absorbed and re-radiated IN A NADIR direction without also expanding the atmosphere, thus, by thermodynamic laws cooling the atmosphere in an equal amount of the heat trapped.
Well, the last time I solved a thermodynamics problem was in 1960, and though it is true that the temperature of the gas will rise , and from PV=RT the pressure or the volume will grow, I cannot tell off hand how the “cooling” and “equal amount of heat trapped” will figure in this.

Earth sans Greenhouse=Earth sans Al Gore…Obvious!

Oh no… someone posted a link above (http://theevolutioncrisis.org.uk_testimony2.php) where one can read Dr Spencer’s less than enlightened views on evolution and the historicity of the Biblical Gospels, among other things. I must admit I was quite shocked by what I read. I can’t avoid being sceptical of anything he writes on climate science from now on, even if it isn’t related to his religious/anti-evolutionist views.

Re: bob (19:17:07) :
“RE: Alex Harvey (16:39:03) :
Alex, all matter emits blackbody radiation, although you are right that gases are not blackbodies.
Some poster here seem to confuse a substances Infared emmision spectrum with its absorption spectrum, they are two separate and different things.”
Thanks, this has to be answered with some care. It is true that absorption and emission spectra for the same molecule are different things, but that is not to say that a molecule can emit radiation at frequencies that it can not absorb radiation or vice versa.
There is thought experiment that covers this, of which I cannot recall all the details, but basically it would allow for heat to flow from a colder bodies of gas to warmer bodies, if I recall correctly.
Also the spectra come into alignment when radiative equilibrium is attained.
The situation with mixtures of gases is a little more complicated as radiation absorbed by CO2 can be passed thermally to H2O and emitted at frequencies that CO2 simply could not.
But finally, if anyone is saying that a gas like CO2 can emit radiation with a continuous spectrum, such as a black body does, then that is not the case.
It is true that the black body spectrum is important when calculating the emissions from a gas, as the temperature of the gas changes the relative (and absolute) intensities of the radiation at different frequencies. But that is not the same as saying it radiates like a blackbody does. Not in my book anyway.
Alex

Spector,
Thanks for your explanation. I think the idea that a perfectly transparent atmosphere cannot cool by thermal radiation would probably account for the peculiarity of a zero lapse rate. I had assumed that the top of atmosphere must be continually cooling by radiation into space and must be colder than the ground, but obviously not.

Nick Stokes (13:53:50) :
“But eventually, the entire atmosphere would reach a constant temperature with height.”
Why wouldn’t the adiabatic expansion mechanism then continue to convey heat downwards (the air would not be motionless because of diurnal effects and thermal inhomogeneity), to restore and maintain (nearly) the adiabatic lapse rate of -9.8 K/km? Surely this mechanism moves heat more effectively than conduction?
There won’t be any mechanical reason for convection in an isothermal atmosphere as a rising parcel would be found very quickly at a temperature lower than its surroundings. Even on a planet with pretty active convection such as ours the environmental lapse rate is not adiabatic. Another way to think of this is, the convection acts as a heat engine. It has only a hot reservoir, though. Without a cold reservoir in which to expel waste heat the engine will stop running its cycle.
bob (14:18:37) :
“Why would this occur? Infrared absorbers like water vapor and carbon dioxide provide an additional heating mechanism for the atmosphere. But at least as important is the fact that, since infrared absorbers are also infrared emitters, the presence of greenhouse gases allow the atmosphere — not just the surface — to cool to outer space.”
You don’t need the greenhouse gases to cool the atmosphere, oxygen and nitrogen are infared emitters according to the Planck black body radiation effect.
But you do need an emissivity above zero. Nitrogen and oxygen have an emissivity of effectively zero. There would be some radiation emitted in the acceleration that occurs when molecules collided, but that would be effectively nil at the temperatures we are talking about here. Anthony suggested that oxygen has some weak IR bands, and thus may have some very small emissivity. However, the atmosphere that Dr. Spenser posits would have some interaction with sunlight in the UV, and he didn’t include that effect.
So the atmosphere cools without the greehouse gases.
thanks

anna v (05:42:08) :
Thanks much for the pointers. Everything you said is correct. I’m familiar with QM. Everything you have pointed I realize. I know of duality also.
How do I put this and stay very simple and pure without numbers? Can’t talk a book worth here.
But this question requires someone so versed in QM & TD they can visually and logically separate a complex system into a single special case that can be exactly (to constants precision) computed and tracked.
I am going to give that special photon’s momentum a value, one, in a transformed unit system that I am going to keep secret (really irrelevant). I have a program with all of the equation in all of science so I can compute anything to adequate precision.
That original special photon travels up X distance and interacts with a molecule because energy levels and the frequency match. All of the momentum is transferred to the molecule, no more photon. I compute molecules position after specific time. The molecule ejects two low level photons, one in this direction one in that direction and a fraction of the momentum still resides in the molecule (no added rotations). I compute. I now have three pieces of the original momentum. I add them up. It’s one with the vector pointing strait up. The molecule bumps another molecule, another split billiard style and one molecule is now spinning, compute, now five pieces. They all add to one and the vector is still strait up.
Get my gist here. It may be that science in universities has become so complex in scientists and students minds that simple core underlying cases cannot be discussed and/or computed without bringing in the hundreds of complex macro-level laws which let us compute things in the real world that otherwise would be impossible. It’s as if most I talk to are unable to go back to the basics. Maybe it’s not even taught anymore. If so, it may time for me to exit science (I’m kidding).
It takes great effort to take a complex system and refine and simplify back to the core laws. But those laws are the foundation of science. Conservation of energy and momentum still apply.
Re-read post above keeping it purely simple and see if the point being made is true (or false). Anna, I do appreciate your help.
Moderator please bear a long one.
Anna:
OK! That’s the key. I know if there are many emission lines, the momentum will be split between the photon(s) of lower wavelength and some residual momentum may reside in the molecule. But conservation of momentum must always be preserved. One place or the other(s).
Please follow. Think only of the original parcel of momentum and keep track of it.
I have read literally a hundreds of papers concerning this broad subject. But I kept having a reoccurring catch in all of the pure logic used. Let’s take this as Einstein would, one infinitesimal thing at a time.
Take a special IR photon, properties set by me, carrying energy thus momentum, leaving a spot on the equator and heading directly zenith to keep this pure.
The momentum carried by this photon, one way or the other must be preserved. The photon may be absorbed by a molecule in proximity if wavelength allows, that molecule hits other molecules so momentum of the molecule changes and is distributed, this can occur many times. But mother nature by her physics is so frugal with her accounting of her energy and her momentum that she will not miss the tiniest portion of her precious energy and momentum.
That momentum from that zenith heading photon may be divided and scattered over many molecules or subdivided into components of other photons in various directions but the SUM of the net effects of that lonely photon’s momentum will end up in portions of two states. One component’s portion (can be zero) escapes into space carried by the original OR divided between some other photon(s) in some direction(s) possibly at different wavelength(s). The other possible state is to cause an infinitesimal but real and exact expansion of Earth’s atmosphere by increased momentum of a molecule(s). This will initially manifest as an increased pressure but eventually will be expansion. The sum of the momentum of these two states (speaking only of the original photons momentum), seems to me MUST be equal to the original momentum of that lone photon to meet conservation laws.
If the above is correct, from here on only speaking of that original parcel of momentum. If the photon didn’t encounter any interaction on its way up, it merely escapes into space. End of story, momentum preserved. However, if it had any interaction and the portion of momentum escaping into space (can be zero) is less than the original, the only other possible state is an expansion of the atmosphere by the remaining portion of the original momentum.
If I’m still right to this point, you can now view that photon’s momentum generically as radiative pressure. And any layer of the atmosphere as a near spherical membrane that this momentum must cross, one way or the other to satisfy conservation of the momentum.
The gist of the above is to say that energy, thus momentum, of outgoing photons cannot be absorbed and re-radiated IN A NADIR direction without also expanding the atmosphere, thus, by thermodynamic laws cooling the atmosphere in an equal amount of the heat trapped.
I’m stuck on this point. Reoccurs in my mind every paper I read and until I can get a understandable answer, I don’t feel an added portion of CO2 that traps additional heat can help but to expand the atmosphere thus cancelling any effect. Some papers support this view but from other directions. I tried to make mine simple.
Any help, corrections or comments?

Alex Harvey (08:00:19) :
“The situation with mixtures of gases is a little more complicated as radiation absorbed by CO2 can be passed thermally to H2O and emitted at frequencies that CO2 simply could not.”
There’s something in that observation. However, the colling of c02 leads surrounding molecules to warm up, and can only do so when it emits at the bandwidth that receiving molecules like oxygen can accept them, though this isn’t the case with H2o, so co2 doesn’t thermalize with h2o – mainly because the thermal excitation of c02 is a tiny part of total heat in the system. In a given volume of air, for each co2 molecule there are about 3000 nitrogen and oxygen molecules, and only around 5% of c02 molecules will be excited at 15C – so the chances of c02 colliding with anoter c02 are quite rare, and it is like molecules which are the most efficient t transmitting radiation. That changes the entire ration of excited cow molecules in a volume of air to the nitrogen and oxygen ones. c02 in th ebending mode doesn’t have the energy to excites a h2o molecule, although it does in the symmetric streching mode – only it has to be at such a high energy that isn’t even found at 35C. As said above, radiation and molecules move in 3 dimensions so for c02 molecules in the upper troposphere where the greenhouse effect is said to be at its mst active, we run into another conundrum: There are even fewer c02 molecules per volume of air that oxgen and nitrogen and the temperature in the mid-upper troposphere indicates that c02 absorbs heat outside of its peak 15 microns, to the shoulders where it coincides with the small peaks of oxygen and nitrogen’s small heat retaining effect – and then there are millions more molecules that co2 has to compete with.

Well… having spent about 2 hrs on this post and blog, I can only come to one conclusion: while it has all been very entertaining, it only shows how intensely complicated it all is, and how far-fetched it is to imagine that the entire thing can be driven merely by small changes to CO2 levels. Most of the above still seems seriously counter-intuitive to me. Methinks the chaotic nature of earth’s systems (per definition as I understand it: multiple non-linear mathematical models interacting) will ultimately prove to be beyond man’s intellect.
As for the (patently extremely simplistic) current state of the art: After initially starting out, some years ago, as merely skeptical, I now doubt even the fundamental premises. I doubt that CO2 levels have actually increased due to man’s efforts… I doubt that earth’s temperature has recently increased beyond margin of error… I doubt the very veracity of the greenhouse effect in this context. Data is suspect.. analyses flawed… motives uncertain.
Perhaps some sense will ultimately come from disciplines other than climate research, hopefully less tainted by agendas other than science. Here’s hoping… (but still reading all this! Keep up the good work!)

I believe the most likely source of outgoing radiation from the upper atmosphere is from solid or liquid particles at the cloud-tops as I believe they emit radiation over a much broader spectrum of wavelengths than gases as a result of their solid or liquid bonding energy states. The problem I see for emissions from the primary gases in the atmosphere is the high probability of re-absorption by the same gases higher up. Perhaps this is the reason for the progressive warming below the stratopause.
I expect that radiation from trace gases just below the tropopause would have a higher chance of getting out because this radiation would be less likely to have an absorption encounter with another molecule of the same gas.
A transmission plot for outgoing radiation emitted from the equatorial tropopause (at 55,000 ft) should show much wider transmission windows as I estimate that over 90 percent of the mass of the atmosphere is below 55,000 ft. based on the reduced pressure at that altitude.
As I said earlier, perhaps the best real approximation of Dr. Spencer’s conjecture is the ancient ice-cube or Ice-Ball Earth climate catastrophe indicated in the geological record.

Re: P Wilson (11:17:15) :
“Alex Harvey (08:00:19) :
“The situation with mixtures of gases is a little more complicated as radiation absorbed by CO2 can be passed thermally to H2O and emitted at frequencies that CO2 simply could not.”
There’s something in that observation. However, the colling of c02 leads surrounding molecules to warm up, and can only do so when it emits at the bandwidth that receiving molecules like oxygen can accept them, though this isn’t the case with H2o, so co2 doesn’t thermalize with h2o – … ”
Sorry, it is a mixture of gases, so they also strive for thermal equilibrium through contact, i.e. collisions. Even if two gases have no overlap in their spectra when mixed that is still the case.
Alex

JER0ME (17:56:12) :
sorry I have lived Norht AND South of the equator and can assure you that Coriolis affects the way the water drains down th plug hole.
Aged 16 went from UK (54N) to Zambia (12S) – almost the very 1st thing I did was confirm that the water went down the plug in the opposite direction to the UK.
Experimental science by observation,
Later over the years I repeated the test – on ships – so I do not know what & why the experiments you cite produced anomalous results.
However easy experiment if you are not on/near the equator :
go to the kitchen/bathroom fill a sink with water – pull the plug – observer which way the water spins.
repeat several times – repeat at friends houses work etc.
Next experiment :
Fill sink with water (very full) stir water so there is a gentle flow in the OPOSITE direction to that observed above – pull plug & observe what happens.
Now – if the Coriolis force is NOT responsible explain the OBSERVED result (every time I have done this is results in the flow direction being reversed as the water drains down the plug hole)
Observation by repeating the experiment trumps/confirms theory every time

Spector (05:44:30) :
RE: kadaka (23:28:44)
I believe you are missing the point. Dr. Spencer is describing a planet with a *perfectly transparent* atmosphere — no greenhouse gasses, no clouds, and no dust in the upper atmosphere.
Nah, not really. Spencer concludes the Earth would be essentially isothermal, as Venus is. There is the lack of water vapor, as with Venus. The CO2 atmosphere is basically an inert gas. From there, examining this simpler system without the preconceptions of how Earth’s atmosphere operates, I can see better what he is talking about. The sulphuric acid clouds and haze do act as an insulator, but then that is only one layer to remove for the thought experiment. Without it the planet would likely be cooler, but otherwise resemble the thought experiment model.
Then, the questions begin. Here it is proposed convective overturning would cease. Yet convection is what drives the Venusian climate. Do the properties of the CO2 as an infrared absorber and emitter make the difference? Here it is argued the Earth would become isothermal. Venus is isothermal, with the convective overturning. Are the sulphuric clouds and haze keeping Venus isothermal? Etc. Just doing the thought experiment from a different starting point, ditching certain preconceptions, and examining what different questions, and what same ones, will arise.

Robert E. Phelan:
If you actually read the link I provided, you’d notice that it is Spencer’s own article describing his belief that the biblical creation story is plausible. But I’m glad that you agree that anyone who is a young earth creationist should not be trusted to have either a brain nor an understanding of science. So we can safely ignore anything that Spencer says.
Not that the article above is actually wrong, but it most certainly is a red herring.

Maybe we should start refering to CO2 as an Ice Age inhibitor.

“Berényi Péter (13:51:12) :
Paul (19:34:32) :
“there are about the same number of molecules of CO2 above any sq meter on Mars as on Earth”
No. The surface pressure on Mars ranges from 30 Pa (Olympus Mons) to 1155 Pa (Hellas Planitia), with a mean nominal pressure of 600 Pa. 95.72% of the atmosphere is carbon dioxide, so the partial pressure can be as low as 29 Pa and as high as 1105 Pa. The surface gravity of Mars is 0.376 g. Should we place this atmosphere in a terrestrial gravity environment, the pressure range would be 76 Pa – 2940 Pa, with a mean of 1527 Pa.
The partial pressure of the same gas on Earth as of now is about 57 Pa. So there are 1.34 – 51.58 times more molecules of CO2 above any sq meter on Mars than on Earth, mean value 26.8.
An up to fifty times thicker carbon dioxide envelope more than makes up for lack of pressure line broadening. Even the highest point has more CO2 above it than on Earth, sea level. The same can not be said about highest point of Earth, Mt. Qomolangma, where CO2 partial pressure is only 18 Pa. Olympus Mons has four times as much carbon dioxide above it, although it is the highest mountain in the entire solar system, peak 27 km above mean surface level.”
the pressure broadening is affected by both the broadening of the same molecule type and the composite of all the other molecular types in the atmosphere. My recollections are that the Earth composite or air broadening is on about the same order of magnitude as that of the self broadening or the effect of other co2 molecules upon a co2 molecule. That being the case, then an atmosphere at 1 atm. (Earth sea level) has a much greater broadening effect than a maximum Martian pressure of 0.01 atm.
while I’ve never tried to run a full calculation on the martian atmospheric column, what I’ve seen from Earth’s is something along the lines of 3.5 W/m^2 for a co2 doubling at 70km with clear skies – which is ballpark of the warmer claims. Despite this significant effect on Earth that appears to be good for possibly almost a degree rise in temperature, the effect on Mars with the equivalent of 5 extra doublings over that of the Earth’s co2 amount is evidently around 1 degree or less for the total ghg contribution which is essentially totally co2. This shows that the actual pressure lower down in the atmosphere is important as well as the fact that co2 itself has rather little effect on temperature, even when there is no h2o vapor to reduce the co2 effects.

Radioactive Man (Norway) (07:14:37) :
Oh no… someone posted a link above (http://theevolutioncrisis.org.uk_testimony2.php) where one can read Dr Spencer’s less than enlightened views on evolution and the historicity of the Biblical Gospels, among other things. I must admit I was quite shocked by what I read. I can’t avoid being sceptical of anything he writes on climate science from now on, even if it isn’t related to his religious/anti-evolutionist views.

Well, you’d be shocked at what Clerk Maxwell had to say about origin of Earth and its age, and scripture, etc., etc., and yet he was “pretty good” physicist–I think he helped organize a few things in electrodynamics.

anna v (22:03:07) :
wayne (10:08:59) :
Come to think of it, even with a billiard ball like gas, where again you could apply your simple model, one molecule with vector momentum 1 hits the other whichis at rest, and sends it in the vertical direction , the total momentum will still be vector 1. To go to the macroscopic case you have to go through classical statistical mechanics which comes out with the average behavior that is pressure and volume.

I see 2 problems with this article .
.
First Roy says :
There is a common misconception that the rate at which a layer absorbs IR energy must equal the rate at which it loses IR energy, which in general is not true.
.
In LTE (local thermodynamical equilibrium) the rate of emission of any frquency (f.ex the IR 15µ of CO2 vibrational spectrum) is necessarily equal to the rate of absorption of the same frequency .
This is due to the fact that the population of each quantum level is given by the Maxwell Boltzmann distribution . This distribution depends on the energy (frequency) of the considered quantum level and on the temperature .
That’s why for a layer in LTE , we have a constant temperature from which follows that the rates of absorption must necessarily match the rates of emission .
If they didn’t , it would mean that the populations of any quantum level vary with time what contradicts the hypothesis that the layer is in LTE .
So on the contrary in the general case these rates must match because the relevant part of the atmosphere is in LTE .
.
Second point is that the average temperature is irrelevant . A GHGless planet , (f.ex let’s imagine a pure helium atmosphere) could have a brutal weather .
To simplify , let’s imagine that the planet doesn’t rotate .
As the surface would be violently out of radiative equilibrium at every point , the surface temperatures would cover n vast range going from over 100°C on the day side to below 100°C on the night side .
These huge temperature differentials would create extremely violent atmospheric horizontal flows between the day and night halves .
So this planet would establish heat dissipation patterns which would involve heat transfers from the day half to the night half whic would look like mega storms .
.
If we allow the planet to rotate , the pattern would change as the Coriolis force and the variation of irradiation with time would probably transform these storms in more complex rotating hurricane like structures .
So definitely depending on the speed fo rotation and the thermal properties of the atmosphere (heat capacity , thermal conductivity , density) the planet would exhibit a large range of probably very violent weather features .

anna v (22:03:07) :
anna v (22:16:24) :
Yes, yes, Anna.
Read my reply to Ron House (05:31:04) first.
If you can, keep thermodynamics and QM in mind but by my careful definition, drop them for a minute. Go back to the basic laws they are built on.
And my only point of all of that was to press the problem I have with radiation and the way it’s currently viewed in science many places and papers, irregardless of whether you speak of classic, thermodynamically, or QM. I’m staying away from angles so sine and cosine factors don’t get dragged in to the conversation. The ‘other’ molecules can have angular velocities but their velocities are irrelevant in my case. I’m not tracking their velocities and therefore momentum. Radiation emitting from the sun will, irregardless of how many interaction and collisions occur, press down on the gases. And, radiation emitting from the surface of the earth will press upwards on the gases, even if a gas (like CO2) has absorption bands in proper frequencies and absorption is occurring. (Of coarse, allowing for the angles created).
I read statements about upward dwelling IR being absorbed by CO2, heating it, and it re-radiating (50% minus dip) back down to the surface and that traps the heat. That to me that totally violates conservation of momentum without accounting for the upward pressure which, since there is no ‘top’ on the atmosphere, will expand it, if pressure preserved in the long run. You have basically have created heat from nothing. Photon leaves surface, absorbed, molecule has v of one upward. Molecule emits photon down and absorbed by ground, molecule has v of two upward. The affect on the ground is null. The molecule has velocity up and therefore heat but from what? Nothing!
We can speak of energy, and of coarse you must in certain cases, and energy must always also preserve, but you lose the vector components which is vital to my point, but science lets me to take that view if I define it that way and in this specially defined view.
Now, do you now see a little deeper in my example. Dr. Spencer’s example brought all of this to mind again and I thought this a place to clarify if someone knew enough to grasp, it seems you do.

Anna:
Now think this. A experiment on CO2 in a lab. The gas is in a enclosure of some sort, lets say flask. Irradiate it. It heats. It can’t expand. Pressure goes up and temp goes up.
Now do same experiment in a topless flask, which we probably can’t do in the lab. The gas can now expand as it heats. I am not that versed in TD enough to answer that question but the results will differ. Do you know in what way? Temp will go up once but CO2 can’t keep absorbing if it’s already in an excited state. A one time increase, right?

“”Alex Harvey (03:17:28) :
Re: TomVonk (02:37:24) :
“That’s why for a layer in LTE , we have a constant temperature from which follows that the rates of absorption must necessarily match the rates of emission .
If they didn’t , it would mean that the populations of any quantum level vary with time what contradicts the hypothesis that the layer is in LTE .
So on the contrary in the general case these rates must match because the relevant part of the atmosphere is in LTE .”
This is just not true. Constant temperature requires rate of energy in, equals the rate out. Heat a gas by another means and it can have a net radiative output and a constant temperature. This is the case for the atmosphere the radiative deficit being made up from sources like latent and sensible heat.
Alex
“”
I think Tom Vonk and I are in agreement here, but perhaps neither of us have explained things successfully.
There is conservation of energy present so if the power in doesn’t balance the power out, there will be a change in internal energy – like a change in temperature or phase change. That includes latent & ssensible heat or conduction and convection as well as radiative. This is not the issue being covered.
What is being covered is that for a parcel of air with ghgs (a thin shell), the emission curve is actually going to be equal to the absorption curve multiplied by the maxwell boltzman black body emission curve such that where there is absorption likelihood of 1 (total absorption) for the parcel then there is an outward emission equal to that of a blackbody at that wavelength and where there is an absorption likelihood of 0, there is no emission. Tom describes it in qm terms that the maxwell boltzman distribution is the distribution of energy states for the gas at its temperature.
LTE, local thermodynamic equilibrium is referring to the fact that in a tiny area, all molecules will be at the same temperature due to energy sharing by thermal collisions. It this were not the case, the N2 molecules might be at 300k while O2 molecules might be at 320k and the co2 molecules in that tiny area might be at 390k or 220k. That is, there would not really be a unique temperature for any tiny local region.
A consequence of this emission absorption relationship is that if the parcel were at the same temperature as the surface (assuming only one parcel for a moment) then there would be no absorption spectra seen and if the parcel were at a hotter temperature, then there would be emission lines present. Finally, if the parcel of air were cooler, there would be absorption lines present but rather than the maximum absorption being one or the output power at a maximum absorption wavelength being zero, the outgoing spectrum would show the power output at these maximum absorption wavelengths as being at the rate of emission of a black body curve for the temperature of the parcel.
A final factor is that the parcel’s outward emission would be the same as its downward emission such that the absorption of radiant energy would be E and the outward emission E and the downward emission of power would be E, assuming the temperature was the same as the surface – that gives 1 E in and 2 E out – an imbalance. That means the temperature of the the parcel would have to drop to the level such that energy is conserved. If it’s in an area where there is convection bringing in more energy, then that temperature can be higher. However, one has a lapse rate defined here without convection.
If you have the same T for space above as for Earth below, then you have balance where the parcel reaching T as there is 2 E coming in and being absorbed and 2 E going out by emission and that means and no convection going on since there is no delta T. Note it is a thin and tiny parcel or the geometry will make things rather confusing and complex.

Re. suricat (19:44:33) :
“I reiterate that; any mass above absolute zero temperature radiates its temperature signature until its mass temperature returns to absolute zero (though this is unobtainable).”
But for many simple gases like N2, that signature is “effectively” no emission.
Incredible as it may seem such gases have virtually no radiative emissions when at earth-like (e.g. room) temperatures.
Yes, it is true that N2 does have IR emission/absorption spectra but the peaks are few (very few compared to CO2) and they are tiny (about 10 orders of magnitude smaller). The are also well off to the high wavenumber end for earthlike (~290K) temperatures.
It is effectively IR transparent, so much so that it is used to backfill to obtain standard pressure when measuring the spectra of other gases. To all intents and purposes it cannot lose heat by radiating it away, when at earthlike temperatures. An atmosphere consiting of N2 would fit the bill of being free of the GH effect. Unless one wishes to be difficult.
Alex

Thanks to Dr Spencer for providing us with the opportunity to learn something. As the scientists would say “This discussion raises the question: Could a planet with a transparent atmosphere have more violent weather than one with abundant water and plenty of CO2?” Haven’t we noticed a decline in hurricanes and tornados in recent years? If heat can exit the atmosphere at low latitudes, doesn’t that mean there is less heat to be rejected at the poles?

Re: TomVonk (02:37:24) :
I think that you need to show more details regarding temperature differences between light and dark sides, and in the case of a rotating earth of temperature gradients in general.
Without the GH effect it is neither clear how, or why, the temperature of the atmosphere would change much even if the surface temperature rocketed up and down. There is a lot of radiative coupling between the surface and the atmosphere that would be missing in a world free of the GH effect.
During night conditions the atmosphere cools itself and and provides heat to the surface but the GH effect is significant in this process. With the surface cooler than the atmosphere convection is not going to provide much heat transfer and that leaves diffusion which is relatively feeble.
During day conditions, convection would be significant but it may just tend to raise the average temperature of the atmosphere above that of the surface, leading to a bit of a standoff.
It is not at all clear to me how large temperature gradients are going to be created and maintained. So I think you need to show more mechanism in this area.
Alex