On the previous thread, I made the point that the reason for Venus surface temeprature being so high was the pressure and that any gas would create a huge warming effect. Chris Colose had made the contention that CO2 is a strong gas and it is responsible for Venus having a surface temperature that could melt lead. This statement, while correct, was placed inappropriately in the middle of a discussion of Earth’s greenhouse effect so I took the moment to explain that it isn’t a realistic comparison and basically amounts to fear mongering. As always, some had contention with my point, so I will attempt to explain further below.
The surface pressure is 93 times that of Earth on Venus. Venus’s gravity is 8.87 m/s^2 whereas earths is 9.78 or about 10% greater. Venus has a surface pressure of 93 Earth atmospheres so we can calculate 93*9.78/8.87 = 102 times the mass of Earth’s gaseous atmosphere. If we divide Venus’s gas atmosphere into 102 separate layers assuming each has the same conditions as the others, each layer has an equivalent (similar) capacity for global warming to Earth’s own due to the retardation of upwelling infrared radiation. An interesting number might be an estimate of how much warming does each Earth mass layer of Venusian gas create? This is an estimate and must be taken with care as there are many effects of the high density gas and clouds in Venusian atmosphere but it is an interesting start point.
My contention was (and is) that the density of Venus’s atmosphere creates a greenhouse effect ‘capacity’ equal to approximately 102 times anything achievable at Earth’s surface. In other words, each Earth mass layer has the ability to retard the heat flow by a similar amount. Using SoD’s (venus with no atmosphere) -43 C blackbody calculation from the thread above and the actual surface temperature on Venus of 460C we see that Venus has an approximate 500C greenhouse effect from its gasses which are mostly CO2 (96.5%).
If we divide 500C GHE/~100 Earth mass atmospheres we get a total greenhouse effect from an Earth thick layer of 96% C02 of only 5C, whereas Earth with its comparatively moist atmosphere runs at about 33C of GHE by some calcs which shows that some Earthly strange and rare gas like dihydrogen monoxide is probably a lot stronger greenhouse gas than CO2. What is also interesting is that from the table Carrick linked in #82 on the previous thread, the CO2 creates an estimated 422C of those Venusian degrees of warming so the total CO2 contribution of an Earth atmosphere that was a massive 96 percent CO2 would be about 422/102 or 4.2C – according to this simplified Venus model. 96% CO2 and a zero feedback temperature rise of 4.2C! hmm.
In other words, the melting of lead on Venus is not simply related to the huge concentrations of evil CO2 but is PRIMARILY due to the huge density of the atmosphere. Also, we can conclude that Venus should be glad that 96% of the gas in the atmosphere doesn’t have the absorption spectrum of water.
the Air Vent 
Jeff,
The issue of the surface temperature of Venus is greatly complicated by the presence of the sulfuric acid cloud layer. The materials of the cloud layer are reflective, which is the reason for the high albedo. The clouds and vapors that make them are also optically absorbing as both droplets and as gas. In order to examine if Venus would be near the same temperature with ANY gas at a comparable density and thickness, you need to look at a gas with out any optical absorption and assume it does not go through a condensation stage and form droplets in the atmosphere.
The sunlight would directly go to the surface of Venus for the ideal optically transparent atmosphere case stated (except for some Raleigh scatter at the higher density levels). The solar intensity would be much higher than for Earth due to lower albedo (assuming low surface reflectivity) and closer proximity to the Sun. The global average surface energy for that case would be a maximum of 750 W/sq m (for zero surface albedo), and average surface temperature about 339 K for that case. The lapse rate (=-g/Cp) would depend on the Cp of the gas, and if Cp were too small (as for Argon), the high lapse rate would result in the gas condensing at a relative low altitude, so Argon is not allowed for comparison.
Using other gases with higher Cp and low condensation temperature such as Helium would have the problem of much lower density, so the mass of the atmosphere would not be the same for equal thickness. We would use thickness as a basis for comparison for these cases. A much higher Cp could result in a lapse rate avoiding condensation (Helium would have a lapse rate of only of only about 1.7 K/km), and the atmosphere could be as thick or thicker as present without condensation. The thickness along with adiabatic lapse rate results in a drop with increasing altitude from the surface temperature value, but the average surface temperature level would still 339 K despite the lapse rate, since all the radiation to space is still from the surface. Keep in mind that the lapse rate is a gradient, not level, and other information is needed to set the level.
Once you include absorbing gases and clouds, the situation changes. First you have to use the correct albedo due to combined cloud and surface reflectance. Even a small percent of absorbing gases and droplets would significantly absorb and radiate some incoming and outgoing optical energy. Keep in mind that the surface density on Venus is about 92 times that of Earth, so even 395 ppm of CO2 (like Earth) would correspond to 0.036 bar partial pressure of CO2 at the surface (92 times Earth). The trace of water vapor and the sulfuric acid clouds, along with the other trace gases also add to absorption. In fact, the density is so high, that even molecular scatter has a significant contribution.
The effect of the absorbing gases and clouds is not to change the lapse rate a large amount (for the same Cp), but to raise the average effective location of outgoing radiation to space from the surface to a large average altitude. The absorption and radiation of the gases and back radiation are the result of this partial radiation insulation, but not the direct cause of the high temperature. This is due to the fact that while there is strong radiation insulation, there is also free convection, and the convection maintains the lapse rate. However, due to the high altitude of the average outgoing radiation, the location where absorbed incoming and outgoing radiated energy balance result in locking the level of the average temperature at that high altitude, not the ground. The higher the average altitude of radiation to space, the larger the delta T to the ground will be (from lapse rate times altitude). This delta T is added to the equilibrium temperature at the location of balance. This is all there is to the atmospheric greenhouse effect. Raising the altitude of outgoing radiation will increase the temperature, but once it is very high, increasing the portion of greenhouse gas has a diminishing return, since density drops off rapidly at higher altitudes.
If Venus had the composition of Earth’s atmosphere, with water vapor and CO2 and clouds as major atmospheric greenhouse causes, this would still result in a very hot surface on Venus if the atmosphere were as thick (tall) as Venus. There would be some difference due to some difference in Cp and also density, and some modest difference of location of outgoing radiation, but the temperature would still be close to the high level of Venus. Lapse rate effects combined with the location of outgoing radiation, not back radiation or thermal insulation, are the cause of the high surface temperature on Venus and Earth. The effect of clouds on albedo can change the level due to a different level of energy in the balance, but is a separate issue here.
The final result is that atmospheric greenhouse gases are necessary for the high temperature on Venus, but only a small portion of greenhouse gases does almost as much as a lot. The same holds on Earth. The much smaller altitude of outgoing radiation on Earth compared to Venus (due to the lower thickness of atmosphere) would prevent a Venus like response even if Earth’s atmosphere had a much higher concentration of CO2. There might be some increase in temperature, but relatively small. Since water vapor and clouds dominate Earth’s greenhouse effect, the net effect of increasing CO2 or any other gas, depend on water vapor and cloud feedback, and these are NOT resolved issues.
Leonard Weinstein #1,
Nice comment; that pretty fairly sums up why Venus is hot. The feedbacks due to clouds and water vapor (sign and magnitude) on Earth are the only important issues to be resolved.
I’ve done similar computations, but my result was slightly different than yours. I remember from college that the acceleration of gravity is 9.807 meters/sec/sec, not 9.78, so that raises Venus’s atmosphere equivalent to 103 earth atmospheres.
The atmosphere warms to 460 C = 733 K from an original figure of minus 40 C = 233 K. That’s a factor of
733/233 = 3.15 times. Radiation is proportional to the 4th power of the temperature, (3.15)^4 = 98.5
“effective atmospheres” as a multiplier.
There is about 0.04% CO2 on earth, that implies the multiplier for Venus is about
103/0.0004 = 257,500 times that of earth. Using Venus as a standard, the atmosphere multiplier effect of earth’s CO2 would be 98.5/257,500 = 0.0004. We get about 342 watts/meter/meter from the sun, multiply that by 0.0004 (ignoring reductioins due to albedo) and we get an increase of 0.14 watts, a lot less that the estimated 3.7 watts for doubled CO2 on earth. Needless to say, Venus doesn’t work as a “scare” story.
Jeff, Leonard Weinstein #1, final paragraph, says I believe what you’ve been trying to get across for the last few days somewhat more succinctly.
In the original Motl/Goddard exchange, Lubos said:
So as long as some greenhouse effect is kept intact, the very dense atmosphere can do the rest.
But if you remove ALL the greenhouse effect, the dense atmosphere alone cannot account for the temperatures, presumably as the lapse rate would tend to zero.
Which I think means everyone has been correct all along, just from differing viewpoints.
steveta_uk said:
The adiabatic lapse rate is only dependent on -g/Cp, so would not go to zero for no greenhouse effect as long as there is reasonable convection. Lapse rate alone is a separate issue from the greenhouse effect. The lapse rate is a GRADIENT, not level, so temperature still can go down with increasing altitude from the surface, whatever the surface level is. It is where the temperature is locked in (ground or at a high altitude) that determines the actual values on the temperature profile.
I’m confused.
As far as I can tell, if Venus had a pure N2 atmosphere, which is transparent to IR as near as damn it, then the effective temperature of the planet would be locked in near the surface, at somewhere around 0C (difficult to know, as the albedo would be very different with an N2 atmosphere) in which case a 50 km high atmosphere would be impossible (N2 freezes around -200C, which would be below 25 km) in which case the very high pressures would be impossible, in which case the whole argument becomes meaningless.
steveta_uk #6,
I think that in a pure N2 atmosphere the surface temperature would be mostly set by radiative loss balancing solar gain. Solar intensity is about twice that Earth receives, or about 480 watts per square meter on average (assuming similar albedo). That is equal to about 303K blackbody temperature (30C). But since Venus rotates very slowly (about once every 243 Earth days, orbital period of 225 Earth days), once side would tend to get hot and the other cold. I do no know how much convection would transfer heat to the dark side of the planet. If the temperature on the dark side were to fall to the liquifaction point, then you would have liquid nitrogen (or even solid nitrogen!) on once side and quite warm temperatures (>80C average!)on the other. Sounds hellish. I’m not sure it is worth much pondering.
In the case of Venus it is good to consider the concept of photosphere, i.e. the layer where the bulk of radiation is emitting.
Earth has a two layer photosphere: the surface and the cloud tops, the radiative equilibrium is established somewhere inbetween.
Venus has a single layer photosphere: sitting at the cloud tops, the radiative equilibrium is established at approximately 55 km altitude, and temperature follows the adiabat from there increasing downwards.
The surface of Venus is hot for the same reason as the bottom of South African gold mines are hot.
Hans Erren,
“The surface of Venus is hot for the same reason as the bottom of South African gold mines are hot.”
I don’t think that is correct. Earth’s geothermal gradient averages ~25C increase per Km of depth, and represents an average heat flow of ~0.09 watt per square meter. (http://en.wikipedia.org/wiki/Geothermal_gradient) That warming has nothing to do with the atmospheric lapse rate, it is due to conduction of heat from the Earth’s interior to the surface.
Steveta #6,
I wondered about that too. I think what would happen is this. A lapse rate has to be maintained by kinetic energy from gas flow (turbulence etc). Heat leaks upward (down the gradient) by conduction, turbulence-assisted, and the adiabat mechanism has to pump it down.
On Earth, that fails at the tropopause. Not enough motion, and too much heat flux up.
In this N2 Venus, you’d get some N2 rain at about 25km (your figure). Rain absorbs heat when it condenses and releases on evaporation lower down, so it’s a strong upward heat flux. That would create a tropopause at about the liquefaction temp, which could go on indefinitely (upward). So you can still have high pressures.
Generally I agree with Leonard Weinstein. I am pretty sure it was he who came up with the “Tall Room” thought experiment.
Elsewhere he has stated that the surface of Venus would be hot even if the CO2 were replaced by an equal mass of Nitrogen, so I don’t think he is denying what Jeff said.
Imagine Venus with a Helium atmosphere and no clouds (no sulphuric acid and no water). The energy balance would be easy to calculate as the Helium is almost perfectly transparent. That too has been done elsewhere and if I remember correctly the answer came out at ~359 Kelvin based on an albedo of 0.3. Voila! No greenhouse effect.
The next step is to bring back the clouds and that changes the situation entirely as the clouds determine temperature and transform the radiative balance (albedo = 0.75).
http://scienceofdoom.com/2010/06/12/venusian-mysteries/#comment-2953
Now all we need is DeWitt Payne to set us all straight.
Steve Fitzpatrick said
June 1, 2011 at 5:10 pm
Hans Erren,
“The surface of Venus is hot for the same reason as the bottom of South African gold mines are hot.”
I don’t think that is correct. Earth’s geothermal gradient averages ~25C increase per Km of depth, and represents an average heat flow of ~0.09 watt per square meter. … That warming has nothing to do with the atmospheric lapse rate, it is due to conduction of heat from the Earth’s interior to the surface.
That is not quite correct and Hans does have a partial point. If you visit any point below sea level – Dead Sea, Salton Sea, Death Valley, etc. – they are all going to be consistently warmer than surrounding uplands. A ride down to the Dead Sea is an experience and the adiabatic effect is very noticeable. In a deep mine the effect is much greater. But, there’s also, as you point out a geothermal gradient as well. So the warmth in a mine should be a combination of both.
Duster #12,
The actual temperature gradient is ~25C per Km below the surface. If a gold mine is 1 Km deep, then it will automatically be ~25C warmer at the bottom than the surface. If the mine were cooled (mechanically) you could make it any temperature you like (assuming you had enough mechanical cooling capacity and insulation!)… it could be 20C cooler than the surface. Or you could seal the mine and pump out half the air (that is, half the pressure of the surface… the temperature would still rise by ~25C per Km depth. The atmospheric lapse rate is not at all connected to the temperature of the air in the mine. There is, unfortunately, a lot of confusion about this subject. The atmospheric lapse rate is a consequence of heat flux from the surface to space; the lapse rate does not cause the surface to warm. Cause and effect too often get flipped around when people talk about lapse rate; I don’t know why.
#12,
Steve is right. In any deep mine the air temperature is the same as the soil temp, and uniform all year round (except maybe for heat from mining). Near us there is a small limestone cave. A few tens of metres in, and the temp is a uniform 10K, all year round.
Hans is also wrong here:
“Earth has a two layer photosphere: the surface and the cloud tops, the radiative equilibrium is established somewhere in between.”
You can see this is wrong from the spectrum looking down. It’s in two parts. The GHG transparent part shows emission at about 270 K (arctic) – that’s the ground. It was clear sky. But the rest is at about 225K which is not cloud tops, but TOA, where GHG emission occurs.
On Venus, it’s mostly TOA, with some clouds, and very little surface.
For the record, I fully agree that 90 bars of CO2 is more effective of a greenhouse than 1 bar of CO2. I don’t think that was ever the issue. The original point was that even a pure 90 bar N2 atmosphere (or whatever other gas you picked) could generate similar conditions as a pure 90 bar CO2 atmosphere; various comments then supplemented this logic with various theories about the ideal gas law, lapse rates, or whatever other hot flavor of the day happens to be (which are all apparently good as long as it disagrees with every scientific paper on the topic).
By the way, some of these experiments of removing CO2, H2O, etc and keeping the pressure constant have been done for the Venusian atmosphere by Mark Bullock for his PhD thesis, and there’s a 1980 paper as well by Pollack et al that works this out too. In both cases, losing the CO2 drops the surface temperature by over 400 K
Venus is 30% closer to the sun.
Chris Colose,
Temperature gradients in the atmospheres of Earth and Venus can be explained based on the concept of adiabatic lapse rates. The theory fits the measurements. So how can you justify this wild statement in your @15 above:
“The original point was that even a pure 90 bar N2 atmosphere (or whatever other gas you picked) could generate similar conditions as a pure 90 bar CO2 atmosphere; various comments then supplemented this logic with various theories about the ideal gas law, lapse rates, or whatever other hot flavor of the day happens to be (which are all apparently good as long as it disagrees with every scientific paper on the topic).”
Cp of CO2 is 0.844 many more here:
http://www.engineeringtoolbox.com/spesific-heat-capacity-gases-d_159.html
Jeff Id:
Thanks for clarifying your position. Increasing pressure, by itself, doesn’t cause higher temperatures, or so I understand you saying.
One comment I would make is that it is important to understand the non-linearities of radiative transfer.
“If we divide Venus’s gas atmosphere into 102 separate layers assuming each has the same conditions as the others, each layer has an equivalent (similar) capacity for global warming to Earth’s own due to the retardation of upwelling infrared radiation. An interesting number might be an estimate of how much warming does each Earth mass layer of Venusian gas create? This is an estimate and must be taken with care as there are many effects of the high density gas and clouds in Venusian atmosphere but it is an interesting start point.
..My contention was (and is) that the density of Venus’s atmosphere creates a greenhouse effect ‘capacity’ equal to approximately 102 times anything achievable at Earth’s surface.
..If we divide 500C GHE/~100 Earth mass atmospheres we get a total greenhouse effect from an Earth thick layer of 96% C02 of only 5C..”
Some interesting mathematical “experiments” were done in the Atmospheric Radiation and the “Greenhouse” Effect series.
These demonstrate, using the well-proven equations of radiative transfer, that non-linearity rules in the atmosphere. More non-linearities in Understanding Atmospheric Radiation and the “Greenhouse” Effect – Part Twelve – Curve of Growth.
Aeronautical engineers will understand this. No one does linear ratios for drag/speed or anything else in mechanics or heat transfer, unless it happens by chance to be the proven equation.
“ ..whereas Earth with its comparatively moist atmosphere runs at about 33C of GHE by some calcs which shows that some Earthly strange and rare gas like dihydrogen monoxide is probably a lot stronger greenhouse gas than CO2.
As everyone in climate science agrees – Water Vapor vs CO2 as a “Greenhouse” Gas. Although simple ratios won’t give you the correct result.
In the end, calculating the effects of increases in CO2, N2O, CH4, O3, CFC11 or any other gas has to be done using the equations of radiative transfer. Not using ratios.
#15, Chris,
The original topic was an AGW article about CO2 on Earth by Happer to which you answered with the scare tactic of Venus. I was careful not to state ‘similar conditions’ to CO2 as you have claimed here.
My reply was that it was the pressure and amount of gas which caused the temperature more than the specific greenhouse effect of some particularly powerful gas. I pointed out that even N2 would cause a ton of warming with wording that clearly recognized there would be less warming and a paper was referenced where even the 96.5 percent N2 atmosphere had 80C of warming. I was also careful not to claim that all gasses would definitely cause a hot Venus and intentionally phrased even that as a question. In other words, you are making assumptions of a point I didn’t state.
To be fair, I admit that a pure nitrogen atmosphere had less warming than I would have (but did not) guess. My wording was done with care to be accurate and directed to my realization of the mechanism of your intended exaggeration rather than a quantitative analysis of Nitrogen’s warming. From this post, I am also surprised at how little warming CO2 creates by itself and at the weak effect it implies for Earth’s current GHE. If I (or someone else) has time, it would be useful to compare the probe-measured amount of CO2 induced warming on Venus at 1 bar of altitude (near space). This would probably be well above Venusian cloud formations in the lower high pressure regions and could give quite an interesting approximation of the net zero-feedback warming possible from CO2 on Earth.
It is also quite apparent that an Earth composition atmosphere has far stronger greenhouse effect (33C at 1 atmosphere) than Venus due to the other ‘pollutants’ – like dihydrogen-monoxide. The comparison wouldn’t look well upon what you call a ‘strong’ global warming gas (C02) as Earth’s rarefied CO2 atmosphere has a far stronger greenhouse effect per unit atmosphere than Venus.
It may be a fun WUWT post if done well.
According to the experts (http://en.wikipedia.org/wiki/Atmosphere_of_Venus) at approx 1 bar, at 50km altitude, the temp is 75C – quite warm, really.
Chris Colose writes “By the way, some of these experiments of removing CO2, H2O, etc and keeping the pressure constant have been done for the Venusian atmosphere by Mark Bullock for his PhD thesis, and there’s a 1980 paper as well by Pollack et al that works this out too. In both cases, losing the CO2 drops the surface temperature by over 400 K”
The result we need to see is what temperature Venus would be with CO2 replaced by N2 at the same pressures but add back CO2 at the same concentrations found on earth. Adding earth-like concentrations of H2O would be interesting too.
I rather suspect the temperatures would be a lot higher than earth’s under those conditions.
steveta_uk,
That is interesting, it doesn’t seem to match the graph directly above it though. I wonder if there is another source.
The graph above also indicates that we’ve already entered cloud layers.
The lapse rate (on Earth or anywhere else) represents the temperature gradient that is the transition between a stable (non-convective) and an unstable (convective) atmosphere. Any circumstance which produces a greater rate of warming with lowering altitude than the lapse rate will lead to convection. Any circumstance which produces a smaller rate of warming with lowering altitude than the lapse rate will inhibit convection. The lapse rate in no way constrains the actual temperature profile except to the extent that temperature gradients steeper than the lapse rate will cause convection… which will increase transport heat upward until the gradient falls to approximately match the lapse rate. Maintaining the actual temperature profile of the atmosphere, on Earth or on Venus (that is, an atmospheric temperature profile close to the theoretical lapse rate) requires that there be a source of surface heat which is greater than or equal to the rate of heat transport from the surface to space which would take place in the absence of convection. In the case of Earth, heat loss to space in the absence of convection can be quite high, because radiation can escape through the atmosphere’s IR window, so thermal inversions, where temperature increases with altitude, are very common near the the Earth’s surface (especially at night when there is no solar surface heating, but there is continued radiative loss of heat to space). (http://en.wikipedia.org/wiki/Inversion_%28meteorology%29)
On Venus, the thick infrared-opaque atmosphere makes radiative loss of heat from the surface to space minimal, and convective heat transport must therefore dominate. So on Venus, the quantity of solar heat which must reach the planet’s surface to maintain the lapse rate temperature profile is very low (and thermal inversions will not take place!). Even if only 5% to 10% of the sunlight reaches the surface of Venus, that heating will be more than enough to maintain convection.
In every case, it is a source of heat at the planetary surface which, if large enough, supports the lapse rate temperature profile, not the lapse rate that creates the temperature profile.
Nick Stokes #14,
“A few tens of metres in, and the temp is a uniform 10K, all year round.”
Unless you mean 10C, you must live somewhere outside of Pluto’s orbit!
Steve #25, does this mean that a very thick N2 atmosphere is possible with a minimal temperature gradient?
In which case, surface temp is set by incoming solar * albedo matching outgoing IR, which escapes almost unimpeded to space.
In which case atmospheric temps are set by conduction only (very slowly).
In which case quite low surface temps are possible despite 90 bar pressures.
In which case Motl was wrong.
Steveta_uk
It is important to consider the extent to which a near-adiabatic lapse rate will actually develop and the depth to which this layer will penetrate. There are two ways to get a high tropopause: either a shallow lapse rate (which is why the tropical tropopause is higher than the polar tropopause, or due to high optical thickness (in the case of Venus). It’s theoretically conceivable for atmospheres to form with a very shallow troposphere and a thick stratosphere (especially where absorbing gases net heat radiatively, rather than radiatively cool). Buoyancy-driven convection transports heat upward where it is balanced by radiative cooling, and convection becomes more sluggish in an optically thick atmosphere.
steveta_uk # 27,
In a pure nitrogen atmosphere as dense as on Venus, the nitrogen would not be perfectly transparent to IR (nothing is really perfectly transparent), so you would have to look at the details to make a reasonable estimate. However, what is clear is that the surface would receive much more of the solar energy (compared to today), and a substantial fraction of the surface heat lost to space would be via radiation rather than convection. There would (of course) still have to be a lapse rate due to convective heating by the surface, even with a 100% nitrogen atmosphere…. the issue of day versus night temperatures (and how much heat would be transported via atmospheric circulation) strikes be as very complicated.
Wouldn’t Mars be a better lab for finding the net effect of the CO2?
No oceans, no water vapor, no clouds, no volcano, no AGW as far as I can tell.
Mars has lots more CO2 than Earth, right?
>95% CO2…
We have lots more data from Mars.
http://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html
NASA says the BB temp ~= the Average temperature of 210K.
I guess it is not interesting because the CO2 is not causing molten Pb like Venusian surface. Or, will Colose enlighten us about Martian heating due to 95% CO2?
RR
Ruhroh,
Yes, Mars is very interesting and provides a great lab experiment to test our understanding of radiative transfer. Radiative transfer equations make specific predictions concerning the spectrum of upwelling radiation by a planet, which can then be compared to observations. This lends far more predictive and explanatory ability, as well as pathways to new research, than naive guesses on the back of the envelope. The TES instrument observed the Martian spectrum for example:
http://tes.asu.edu/
If bloggers like “GallopingCamel” were right and all the experts were wrong, we wouldn’t really be able to explain spectral observations on planets.
Chris Colose #31,
If “all the experts were wrong”…..
Yikes! Some advice from one who is quite old to one not nearly so old: frequently the experts really are all wrong. Please remember that Jame’s Hansen’s early 1980’s estimate of climate sensitivity (4.2 C per doubling?) has already been revised downward several times (GISS Model E now stands at 2.7 C per doubling), even though it appears Dr. Hansen has never accepted much of the downward revision. I suspect strongly that you can count on that downward trend of GISS estimates of sensitivity continuing.
The tendency of people to believe their own publications and press releases (AKA confirmation bias) is overwhelmingly strong. The better known the person, the stronger the confirmation bias. I urge you to treat the pronouncements of all experts with enormous skepticism…. the better known the person, the more skepticism is prudent.
I note that “experts” are often wrong!
Definition of expert- a ‘has been’ drip under pressure.
@31;
So, how much is the Martian CO2 heating the surface above what we would expect with , say, N2 instead?
I thought the initial Venusian issue was surface temps hot enough to melt lead, due to CO2, if I understood your statement correctly.
RR
Steve, #26
Yes, 10C not 10K. Actually, I toured the cave back in Fahrenheit days, so I was converting from 59F. F, C, K, it can get to be a bit of a blur.
Nick Stokes #36,
I understand. Age and time blurs much…
I actually toured similar caves at the north end of the Blue-Ridge Mountains many years ago…. same deal with constant temperature, but I remember about 52F (11C) was the constant temperature. Still, a nice change from July daytime heat.
Why does gravitational compression heat up gases and solids and non-H20 liquids?
What is the actual physical explanation?
Because it is the reason that the cores of the Stars reach 10 million Kelvin before nuclear fusion takes over.
The core of hydrogen-helium Jupiter is close to 20,000K (and no solar energy is getting down there). Solo Brown Dwarf Stars (with no solar forcing fusion Stars to provide energy) take a billion years to cool off from millions of Kelvin (although we do not know what temperature they cool off to).
The act of compression itself is thought to cause the temperature increase, but once the compression stops, the temperature stops increasing and, supposedly, it starts to cool off. But does it ever cool off enough to reach 3K, the Cosmic Background Radiation level.
The physical explanation will point to whether there is still a constant equilibrium temperature that will be achieved even if there is just constant gravity and no further compression. Doesn’t gravity provide a constant force acting on the matter even if there is no further compression.
I suspect this is still a Non-Zero, Non-3K equilibrium temperature level.
Ruhroh,
Jeff’s post, at least qualitatively (but not quantiatively),could give you a good indication of what’s happening. There is not much pressure in the Martian atmosphere to broaden the absorption features of CO2, so even for 50-100x the amount of CO2 per square meter than on Earth, the equivalent width of its spectral features is even less and there’s very little ability to generate a greenhouse effect. The lack of water vapor as some have noted, and being further from the sun help too (actually, in the high latitude regions of Mars, it gets cold enough for CO2 to condense, resulting in larger seasonal fluctuations in the mass of the atmosphere).
On “experts”: I appreciate the revelation that people are wrong, knowledge advances, and hypotheses with better explanatory and predictive ability gain further attention. Using this simple fact to justify believing whatever you want and pretending all opinion’s are equal is intellectually bankrupt, ignoring the amazing track record of what experts do right (and where the textbook knowledge actually works), to me defines the climax of laziness in actually learning a subject, as at least two commenters who tried this tactic on me just revealed in themselves. I also don’t see any point in replying further to people who believe or would even imply this, which unfortunately seems to compromise half of the people in this discussion. Sorry. You could try this tactic in a physics class and tell your professor that gravity actually won’t make a ball you throw in the air come back down (even after direct observation!) but your well-deserved F shouldn’t be surprising. Nor should it be surprising when radiative transfer theory, which has developed for over a century, actually works instead of guesswork based on uneducated reasoning.
Chris Colose,
“Using this simple fact to justify believing whatever you want and pretending all opinion’s are equal is intellectually bankrupt, ignoring the amazing track record of what experts do right (and where the textbook knowledge actually works), to me defines the climax of laziness in actually learning a subject, as at least two commenters who tried this tactic on me just revealed in themselves.”
I do hope that you are not suggesting I am intellectually lazy. I can assure you the truth is exactly the opposite. In every physics class I ever took (and there were many) I got A’s. I understood radiative transfer quite well when you were either unborn or in diapers. I suggest you stop insulting people.
Steve– I have no doubt some people here have science background or are not “dumb,” which makes the persist number of unjustifiable statements and attempts to “play dumb” that much more confusing to me.
Chris Colose #41,
Do you suggest that my comment #32 represents an unjustified statement or an effort o “play dumb”?
It is neither.
When I was in my late 20’s I did research work on polymers. I once attended a technical conference dedicated to a “deeper understanding” of the kinds of polymers I worked on. I listened to several presentations by the “leading lights” in the field (some quite well known). It was clear to me (based on my own research results) that much of what these folks said was just wrong… and obviously so. I did try to talk with a couple of them and explain how I thought they were mis-interpreting their own results: they would hear NONE of it. They would not entertain the possibility that they were wrong. It turned out (later) that they were in fact quite wrong, but my efforts to engage them on the technical substance was rejected. This is neither uncommon nor something that is unique to science; it happens everywhere and in every field of study.
Experts do have knowledge, but they are also terribly subject to confirmation bias. Most are neither aware of this nor able to control it, but you can (and should!) take it into account when you hear what an ‘expert’ has to say… on any subject.
Bill Illis,
If there were no constant energy source adding energy into the system, yes, it would eventually cool. But, in the case of planets in our solar system, that ain’t the case. As long as the energy in == energy out it will maintain whatever temperature it ultimately attained (not that a temperature is meaningful in any context other than a homgeneous medium.)
Mark
Steve– This is a boring discussion so I’ll leave it at this, and I’m sure you have your own thoughts on the matter.
I completely agree that ‘experts’ love to cite their own work, have egos, can and have been “wrong,” etc. This is why there’s always a good need for for many experts from many groups around the world, an efficient peer-review system, and the opportunity to continue research with freedom from persecution of findings. In the end, science is a self-correcting process. With respect to climate change, this is really why huge bodies like the IPCC exist…to summarize and assess the balance of evidence, rather than have the entire structure of climate change rest solely on one study or one line of reasoning. This is why the National Academies issues reports on various topics. For people without the background to assess the science, it also provides the best means of sorting out the current knowledge from personal opinion; if everyone took every blogger off the street as seriously as the National Academies, nothing would ever get accomplished. And if you have sufficient evidence for the validity of a counter-theory, you publish it and have your work reviewed and tested by the leading experts in the field. If it works, eventually it will inevitably be undeniable and a new ‘consensus’ will emerge– see Wegener and plate tectonics. What you don’t do is whine about it on blogs.
With all due respect to the Galileos and Darwin’s of of the world, modern science evolves primarily through study on very fine details rather than radical paradigm shifts that overwhelm dozens of disciplines at once. This is especially the case for things like the physics of motion, where there is a long-standing history of theory and observation. There are certainly fields, perhaps like the study of ancient Roman equestrian medicine, that are so specialized and so only a handful of experts in the world exist, where I’m sure the high school textbooks will contain information 50 years from now completely different from that in modern ones (if the latter has anything at all to say). The same is of course true for very young fields where observations are just first coming out– like the astronomical work of extrasolar planetary systems.
This is far from the case for thermodynamics, atmospheric science, or radiative transfer theory, where the general principles of planetary energy balance, the maintenance of the lapse rate, the ideal gas law, etc are very well understood. This is to say that the basic physical principles people learn in 100 level meteorology courses are not likely to be radically altered by people like “GallopingCamel”, although they are of course welcome to try. The key things for experts to study are then in the fine details, such as how aerosols of different composition alter the radiative budget– things which are more specialized and have little influence on the “big picture.”
Of course, in science, we do not expect the experts to always be right. Otherwise intelligent hypotheses would never get advanced. When Richard Lindzen advanced his cloud-feedback IRIS hypothesis, he was taking a chance, making an educated hypothesis, and by publishing he is implicitly making a call for the observational specialists to test his work and the dynamicists to examine it in more detail. This is how good science is done– and that has nothing to do with whether he was ultimately “right” or not. Of course, to do this requires elementary background in the subject you are working on and a familiarity with the current knowledge on the subject. You don’t walk into a field without having read so much as an intro book on the subject, and then claim that your voice is just as equal to the “experts” under the argument that authorities get things wrong. That’s just bogus and anyone defending that line of thought hasn’t got a first clue.
Chris Colose @28,
The adiabatic lapse rate is lower at the Earth’s equator because there is more water vapour in the atmosphere at low latitudes. “Wet” adiabats are lower than “Dry” ones.
At high latitudes where the atmosphere has a relatively low water content, the measured lapse rates are close to the theoretical “Dry” lapse rates.
I am puzzled that you disagree with what seems blindingly obvious to so many people including Steve Goddard and Lubos Motl. Appealing to the “ex cathedra” argument is futile.
Bill Illis, @38,
Lapse rate theory agrees with measurement in our oceans but the gradient has the opposite sign to what is seen in the atmosphere; temperature falls with increasing depth. The temperature falls until it reaches 4 degrees Centigrade at about 1,000 meters depth. This is the temperature at which water reaches its maximum density. After that any further increase in density relies on the limited compressibility of water.
Thus it is that most of the Earth’s sea water is at temperatures ranging from 1.6 to 4.0 degrees Centigrade.
If any of you feel inclined to argue with me about temperatures in the deep ocean, the first long lived transatlantic telegraph cable was made in 1866 at Greenwich in London. The “Chief Electrician” was C.F. Varley who hired William Thompson (Lord Kelvin) as a consultant. Both of them made fortunes while their boss, Cyrus Field died a pauper.
Kelvin knew that the temperature at the bottom of the Atlantic ocean was 277 Kelvin so he built 14 cylindrical tanks each with a volume of 500 cubic meters. The entire length of the cable was installed in these tanks which were flooded with water cooled to the appropriate temperature. Kelvin was able to test the entire system under realistic conditions before one meter of cable was installed.
How do I know? While building prototype cables for TAT-8 (the first transatlantic fiber optic cable) I grew rainbow trout in commercial quantities using the tanks that were built for Lord Kelvin.
Jeff,
While I realise this is completely off topic, I wanted a break from arguments that are about as productive as Bishop Usher on the precise date of the creation or the number of angels that can dance on a pin.
#45
“I am puzzled that you disagree with what seems blindingly obvious to so many people including Steve Goddard and Lubos Motl. Appealing to the “ex cathedra” argument is futile.”
Seems to me you just have different saints. And very odd ones.
Chris Colose #44,
I am puzzled that you seem to find so many seemingly important issues boring. But to each his own.
WRT were experts are wrong: Of course no expert is likely wrong about basic things (like lapse rate, Stefan-Boltzman, etc.), but it does not take an expert to understand those things. Were experts are very often wrong is where knowledge is truly limited, and people tend to make an educated guess, or if you prefer, an educated hypothesis. In the case of climate science, it seems to me that even testing that kind of educated hypothesis is fraught with problems… data is noisy, very limited, and often in conflict with other credible data. We need look no further than the range of calculated climate sensitivities from CGCM’s to see that there is much which is not clearly known… and so the educated guesses of experts are substituted. This is the kind of environment where confirmation bias can cause big errors, and get in the way of progress. The strong personal/political/philosophical leanings of most of those involved in climate science add even more risk of confirmation bias. The only reason that I spend time thinking about climate science is because I believe it is terribly important to be sure weak science does not lead to public policy with costs that vastly outweigh benefit. You seem to suggest that a scientist or engineer with many years experience working on complex systems and noisy data (outside of climate science) is incapable of critically evaluating the quality of the work done in climate science. I respectfully disagree.
gallopingcamel:
FWIW I ordered bandwidth on TAT-8 and PTAT-1 as they became available.
There was a book “Voice Across the Sea”
(Arthur C.Clarke 1958) that described the various attempts to lay a workable cable. It has an intriquing chapter “The Man Before Einstein” that dealt with his contribution to telegraphy but also his (amongst others) early formulations on the mass of the electromagnetic field (m=E/c^2 type stuff) and his Operational Calculus.
Alex
Oops!
It has an intriquing chapter “The Man Before Einstein” that dealt with Heaviside’s contribution to telegraphy …
gallopingcamel:
I think that there are two effects, the first deals with a gradient that makes the bottom cooler than the surface.
Munk’s steady state thermocline:
http://oceanworld.tamu.edu/resources/ocng_textbook/chapter08/chapter08_05.htm
The second deals with the difference between in situ and potential temperatures:
http://oceanworld.tamu.edu/resources/ocng_textbook/chapter06/chapter06_05.htm
Now I think it is the common use of potential temperatures in graphs etc. that hides the neutral bouyancy lapse rate which gives thermometer temperatures that increase with height in the abyssal ocean. See what you think.
Alex
Oops again!!
Now I think it is the common use of potential temperatures in graphs etc. that hides the neutral bouyancy lapse rate which gives thermometer temperatures that decrease with height in the abyssal ocean.
Alexander Harvey,
Thanks for those comments. Now I need to apologize to Jeff Id for derailing the discussion. My intention was merely to further demonstrate the utility of the lapse rate idea.
Steve Fitzpatrick @32 & @49,
While we appear to have a “Failure to Agree” when it comes to “Tall Room” experiments, I do agree with most of what you say, particularly when you suggest that “experts” are frequently wrong.
Let’s remember that one of the most frequently cited sources of information on climate science is the IPCC. Many of us think that the IPCC’s scientific gaffes result from making science subservient to politics.
Steve,
I agree with most of what you said, and it applies to all fields of science too, especially the physical sciences in which the “lab” takes the size of a rock formation, a planet, or even a solar system (in the case of astronomy). We don’t have the luxury of perfect answers except in very special cases. That does not give people the freedom to reinvent their own physics, pretend nothing is known, or prevent us from having the ability to give useful constraints on the answer we’re looking for. This is the case, for example, in understanding how stars evolve. We cannot observe a single star evolving over billions of years, but we can combine theory (with powerful stellar models) and observations of other star systems to create a coherent picture of how things work. And we can easily say why certain things just don’t work. Sometimes it takes a bit of cleverness, and in no case is progress made by bloggers hand-waving that we don’t know anything and throwing their wild ideas around. As SoD and others mentioned too, if people have their own back-of-envelope theories, they need to explain things just as good or better than current theories, otherwise it’s useless.
Who is Chris Colose? He seems very young and immature in his opinions. It seems that he hasn’t much real-world experience.
Mea culpa – I just looked him up. Chris Colose is a student. That accounts for it.
Steeptown,
He is not hiding who he is:
http://www.aos.wisc.edu/~colose/
Steeptown,
we cross-posted
Post #55
“As SoD and others mentioned too, if people have their own back-of-envelope theories, they need to explain things just as good or better than current theories, otherwise it’s useless.”
I guess what you say is what I was hoping would occur early in this discussion/thread, i.e. someone would give a link to a publication(s) that would have explained the singular effects of CO2 on the Venusian atmosphere and how that related to the climate of the earth. Has someone pointed to these publications that agree on the CO2 effects and at what point in the thread where they linked and by whom?
Chris, I think you may be looking too hard for the straw men and not addressing the more detailed and intelligent questions/points that are posed in threads such as this one.
I have, from the beginning, credited your line about Venusian CO2 as a throw away one in making the point about GHG effects on climate are the same whether they are defined as pollutants or not – which we get to by assuming no intelligent life created the CO2 on Venus. I would agree that Happer writes his article more from a layperson/scientist perspective than one of a climate scientist and that such articles have less credibility than those that are published in strictly science journals. I would assume that the bigger issue being discussed by Happer is that of the EPA regulating CO2 by defining it as a pollutant. I would suggest the EPA had to do more than simply state or point to scientific literature that shows that GHGs, including CO2, have warmed the planted – they had to show harm or potential harm. That is perhaps the point that you could have discussed in more detail.
When you say the climate scientists and scientists from other areas make comments, such as Happer has, that they do so because the comments would not pass muster in a scientific journal, I would agree with you. At the same time that you point to that weakness of the consensus critics would you also acknowledge that those scientists of AGW consensus POV, and particularly the advocate/scientists, are just as susceptible to this weakness and that much of the consensus involves scientists extrapolating evidence they read about in fields and areas of climate science where they are not expert or even perhaps not very knowledgeable?
Kenneth,
First of all (despite what people who can apparently read my mind will tell you), I have never intended to make a specific comparison between Venus and Earth, in the sense that I am using Venus as an example of what Earth might end up like in the not too distant future. In fact, I have publicly stated (for example, on RealClimate) that runaway greenhouse conditions on Venus are *impossible* to achieve on Earth in the modern day. Nor can you use Venus to say anything useful about anthropogenic-scale issues like climate sensitivity, since the radiation is much different on Venus than on Earth, even if the core fundamental principles of physics still apply.
As you said, my original point was to say that whether CO2 was a “pollutant” or not was irrelevant to the problem of global warming, but we’re far away from the original point now. I had never thought people would read so much into that quote, which I thought was very basic logic.
The broadest relationship you can make with Venus, at least as far as CO2 is concerned, is that both planets lend confidence into the strength of radiation transfer theory and give testimony to what a greenhouse effect can do. CO2 is a good greenhouse gas on both planets, and a pure 90 bar N2 atmosphere cannot generate a similar surface temperature on Venus. For a blog like this, I find a good starting point is just to see if I can get people on the same page concerning how the greenhouse effect works, how it keeps both planets warmer than if only the incoming sunlight mattered, and to agree that CO2 is a large contributor to both planetary greenhouse effects. Apparently we’re not all on the same page on these basic facts, so it makes more developed discussion difficult.
I have supplied a list of at least a dozen or so peer-reviewed articles that all agree on these basic facts. For some discussion on the role of CO2 I would look at Pollack et al’s 1980 paper on the Venus greenhouse, or Mark bullock’s more recent PhD thesis (which eventually developed into a paper on the geologic evolution of Venus, with David Grinspoon), but there’s a large number of papers on this issue. The only objection to these works, if people even bothered to read them, is that experts can be wrong…apparently that wins points in the argument and translates into my opinions being immature. Such is the blogging atmosphere.
Nope you didn’t make that claim, but in attempting to critique an article written for layman you wrote your own laymen article including Venus as an example of CO2 being a strong greenhouse gas. Turns out that the CO2 isn’t really the issue but the huge and complex atmosphere is. Standard scare-fare from the believer community.
I don’t mind reasonable discussion or critique but whenever I see a ‘scientist’ using Venus as an example, it makes me cringe. It’s like listening to Real Climate screaming that Mann’s articles prove that today is the warmest in 2000 years when it is flatly obvious that nobody knows except for those with motive.
Don’t throw Venus in next time and I’ll be a little happier. It is a non-sequitur for Earth AGW and a great way to scare people who don’t get the physics.
On the previous thread TimtheToolMan left:
“The point of all this is that there are absolutely fundamental differences between Earth and Venus and so no comparison between the two can be sensibly made particularly with respect to CO2′s role in the atmosphere.”
Exactly right in my opinion and that is EXACTLY what makes the Venus reference a scare tactic by someone who holds themselves out as an authority.
The corollary to earth does not exist Chris, and my hope is that you learn a little humbleness from dropping that kind of response to the technical community. We are not that ignorant despite the hopes of Real Climate style scientists and in far too many cases we are ahead of the curve.
Wisdom comes from being wrong. Climate science is afforded little wrongness on human lifespan timescales. The god of physics insures that us engineers are served humble soup all the time. Are engineers smarter — sorry guys — nope. Are we wiser from experience — no question whatsoever.
Chris Colose’s open page
Has CO2 embiggened.
Read the next page, Chris.
=============
For what its worth I had no trouble not being scared by Chris’ reference to Venus even though I kno little about this. His example had no comparison in mind and it was clearly used as he said it was several times, i.e., it doesn’t need to be a “pollutant.” Not to say anything about our host, but really…?? This is why skeptics aren’t “ahead of the curve.”
That Venus has a higher surface temperature has nothing to do with the “greenhouse effect” and for that matter the atmospheric tempeature distribution has nothing to do with those greenhoses of nurseries. They keep warm because they are closed.
Please read the article of Joseph Postma, who explains why the temperature of Venus is about 500 Degree C.
Click to access Understanding_the_Atmosphere_Effect.pdf
JWR,
I strongly recommend that nobody read the link you gave. It is incorrect throughout and if you read it until you understand it, the article has sucked the brains right out your ears and left a vacuum behind.
@ JEFF Id
You do not say why it would be wrong.
Johnson from Sweden also say that backradiation -from cold air to warm earth surface- is not possible, according to the second law of thermodynamics.
Johnson made a very interesting remark:it seems that sceptic people now start to claim that they own the scepsis, and nobody else should come with different arguments.
He mentions explicitly
Lindsen ( a former IPPC member, but now a sceptic on temperature measurements),
Monckton (who used to be the science advicer of Thatcher, and adviced her to come up with the CO2 argument because the UK unions sabotaged the transport of coal during cold winters, and UK went nuclear)
see the blog of Johnson at
http://www.ilovemycarbondioxide.com/
I might end with a remark in the trend of yours:
Did you read it, did you understand it or you could not understand it because there was a vacuum to start with. Do not get upset, the second law is not understood by 99% of college students.
But say it simple like this: heat is not flowing from cold to warm unless you do work.
The temperature gradient in the atmosphere is defined by the lapserate;
for dry air dT/dz = -g/cp degreeC/m ( g gravityconstant = 9.81 m/sec2, cp specific heat = 1000 J/kg/degreeC. note J = Nm = kg*m/sec2*m = kg*m2/sec2)see also wikipedia: lapse rates.
We usually say adiabatic lapserate of dry air = -9.81 degreeC/km, and some authors drop the sign.
The adiabatic lapserate of humid air is measured to be about -6.5 degreeC/km, the difference because of the latent heat which is coming free when humid air rises.
Joseph Postma gives it in more detail, without going into mathematics.
Johnson on the other hand, starts with the discussion between Einstein and Planck on the wave theorie vs the quantum theorie, a discussion which they could not bring to an end.
Johnson comes up with a model of “waves carrying photons” when the wave goes from warm to cold and “empty waves” from cold to warm, not carrying photons.
Please leave this post on the site for people who do not have, to use your words, a vacuum between the ears. Try also not to mix up calling adiabatic lapserates (dry or humid) with the false name “greenhouse effect”. The temperature in greenhoses in nurseries is higher tan the ambient atmospheric temperature because convection is hindered. That is the error which IPPC makes.
JWR,
The 2nd law says the NET flow of energy must be from hot to cold.
It does not say that ALL flows of energy must be from hot to cold.
The NET flow of energy is always down in the atmosphere is near zero since incoming radiation must balance outgoing radiation +/- any energy stored in the oceans.
This implies that energy must be going up and the only question is what form it is in.
Deep mines. Deep drill holes. The world’s deepest drill hole of 12.6 km at Kola, Russia, gave ROCK temperatures of 180 deg C, at which the rocks were plastic and closed in if the drill bit was lifted. (You might like to speculate why the rocks did not close in under enormous pressure in the harder rock interval above). Assuming the surface rocks to be 0 deg C, this gives a rock geothermal gradient of about 14 deg per km. This is one measure of geothermal gradient, but it cannot be generalised. Different parts of the Earth vary, see below.
How hot is the air in the Kola hole? Assume it is stationary, not convecting. Assume it is dry. The dry adiabatic lapse rate in the atmosphere is about 10 deg C per km, so the bottom would be extrapolated to 120 deg C warmer than the surface air, here probably close to zero deg C. However, the mechanism of adiabatic lapse requires movement upwards of some air parcels and movement down of others, so the stationary air in the hole would not show an adiabatic effect. Quite obviously, conduction from surrounding rocks would soon bring it to equilibrium temp of 180 deg at base.
Deep mines are usually air conditioned. At Warrego near Tennant Creek, Australia, we mined to 960 m below surface. The rock temperature in the sump at that depth was 55 deg C when first exposed. The surface air temperature would have averaged some 25 deg C from BOM records (Tmax+Tmin over 2). Assuming that surface rocks were about the same temperature, on average, as the air contacting them, we thus have a geothermal rock gradient here of about 30 deg C per km. It is not known why it is high. So, cooling of air was needed for miners to survive in 55 deg C working temperatures.
About 70 m below surface at Warrego, the base of the water table formed from artesian water because the rocks below were not weathered or fractured enough to be very permeable. A chamber and pond was made, mine air was blown over the pond to cool it by latent heat of evaporation and it was then sucked down deeper. The ponded water was about 22 deg C, close to the above estimate of the surface temperature and there was discharge and recharge. There was a mechanical air conditioning system as well, and it had to be large because compression of the air as it was forced deeper into the mine caused it to heat adiabatically. It is important to this discussion to note that if the air flow was turned off, to a first approximation, the stationary air in the mine equilibrated with surrounding rock temperature.
There are engineering papers that factor in the air conditioning plant capacity needed to overcome compressive heating as air is pushed to deeper locations. Here is one simple rule of thumb from a set of more complex considerations –
Dry air increases in temperature about 5.4°F per 1000 feet. One BTU is added to each pound of air for every 778 feet of decrease in elevation, or is subtracted for the same elevation increase. For dry air, the dry-bulb temperature change is 1/(0.24 x 778) = 0.00535°F/ft., or 1°F/187 ft. elevation.
http://www.onemine.org/search/summary.cfm/Calculating-Underground-Mine-AirCooling-Requirements?d=C729DC22DCD6A91526D6036F1B032613114AA79B71500A0D31255526C12341625783&fullText=Adiabatic%20compression%20of%20air
This is part of the problem of assuming that a gas under pressure – returning to the Earth atmosphere case – is hot. No, it is hot only if the system is moving fast enough. Think of a bicycle pump. The pump heats the air by compression, it goes into the tire and it is hot. When pumping stops, it cools again to ambient, although it is still under pressure. However, if the tube has a hole and you have to keep pumping to maintain the tire pressure, the tire will get hot and stay hot so long as you pump. This is a type of analogy to the height in the atmosphere that forms a discontinuity because of inadequate convective/conductive transfer above it. Above that height, radiative transfer must dominate. (This does not mean that it might not dominate at lower altitudes in some circumstances).
BTW, on a hot day the local kangaroos go under a tree (reduction of radiation) and dig a shallow hole among tree roots (more cooling by evaporation of root moisture; and an averaging of the daily high/low surface temperatures with depth, a conductive effect).
This will get too long if I continue, so it’s part 1 of a potential series based on observation rather than modelling and theory.
69.TimG said June 4, 2011 at 8:14 am – The 2nd law says the NET flow of energy must be from hot to cold.
Granted; but given some papers maintain that the sea is often a few degrees colder than the air above it, can such air effectively warm the sea? This is a more important question than it seems.
JWR,
Sorry, but every time I read the Venus comparison to Earth my eyes roll back in my head and similarly anytime someone tells me that infrared radiation can’t flow from a cold body to a hot one because it violates the second law of thermo, I get the same response.
Infrared most certainly can flow from a cold body to a hot one, and if the cold body is blocking an even colder one — like the 3K vacuum of space — you can create warming.
Here’s an experiment, stand 5 feet from your freezer door and have someone open it. You can feel the cold on your face instantly yet no convection has occurred. Close the door and your face feels warmer again. But wait, is the skin of the door cooler or warmer than your face?
Congratulations, you just warmed your face with IR emissions of an object that is colder than you. The net flow is from your face to the door, but that doesn’t negate the IR from the door striking your face.
Just how would an infrared camera work in your link’s world if it were warmer than the object it was imaging? — It wouldn’t!! But it does…hmm..
After that revelation, I hope we can discuss something more interesting.
Jeff What the heck has that to do with the 2nd Law? The net flow of heat is from hot to cold unless you do work. Nothing is doing work in your example. Potsma is correct and so is JWR.
Jeff Id
I give you another problem.
In a sauna you put your back or your finger against the wall and you do not burn yourself if indeed you touch the wooden wall.
If on the contrary if, in a not wel maintained sauna, you touch a screw, you risk to burn.
How come?
The temperature in the steady state sauna wall, before touching, is equal!
Try to explain it.
In your freezer problem, with the door open, your face with the speed of light , feels the colder freezer surface and send more heat from your skin at 37 C towards that colder inner freezer wall.
JWR,
Electromagnetic radiation is different from conduction. It can flow both ways simultaneously (actually conduction does too but only on a microscale). The sun is brighter than your flashlight, does it force your flashlight off in the daytime?
The net flow is still from sun to the flashlight. The sun is heating the flashlight.
Jeff Id
Certainly, electromagnetic radiation is different from conduction.
Johnson from Sweden,as I said already, is making reference to the discussion between Einstein and Planck. The two experts could not agree with each other whether light (and heat) travel according to the wave theorie or according to the quantum theorie.
Johnson has a prilimary model, in which light travels in two directions and heat only from warm to cold. That solves your infra red camera problem, and the statement that some people claim that they have measured “backradiation”. Probably only IR light, but not photons travelling from cold to warm.
#76 Correct, the NET flow is to the flashlight BUT there IS flow from the flashlight to the sun.
Publius_Lxxii @ Post #81:
“In the shotgun blast of links emanating from the keyboard of Chris Colose in the direction of GallopingCamel (comment 71), a good number of them appear to simply repeat Venus-is-hot-due-to-CO2 claim.
However, there is at least one BB which appears to head in the general direction of the heart of the issue. On page 74 of the Bullock dissertation
(http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.75.6539&rep=rep1&type=pdf) Tables 2.4 and 2.5 list changes in Venus surface temperature predicted from the replacement of various gasses with nitrogen. The 400K+ reduction in surface temperature listed for the removal of CO2 appears to be in direct conflict with your statement –
“if you replaced Venus’s atmosphere with one of Earth’s composition, you would still have plenty of heat at the surface -even if you took the CO2, Water and Methane out.”
In order for your statement to be true, it appears to me there would have to something very wrong with the analysis behind those tables.”
I was hoping, Chris Colose @ Post #61 above, that you would have noted the link above because in my estimation it took that far into the thread to get something distinguishable from the tangential mentions in linked publications of CO2 and its effects on the Venusian climate. Leonard Weinstein short dissertation in the first link above appears, in my less than expert judgment, to have good merit also. Those are the pieces of information that I always look for in threads such as this one and the preceding one.
They are both electromagnetic radiation in this case. When does electromagnetism stop and magic start?
Jeff @ 78
Everything at temperature is radiating in all directions; surely nobody argues with that. What is the argument about? We know that regardless of the radiation, net heat is in the direction of from hot to cold, unless we are doing work.
Jeff,
You haven’t commented on Leonard Weinstein’s short dissertation. Any comments on it?
Steeptown:
Well, let’s look at this: JWR claims that ” backradiation -from cold air to warm earth surface- is not possible, according to the second law of thermodynamics.”
Um, no. That is actually just complete nonsense. Not correct at all. 0 out of 10.
I’ll explain why, but let’s start here, this is a 19th century view of thermodynamics: “The net flow of heat is from hot to cold”.
“Heat” doesn’t “flow”: There is no physical quantity “heat”, it’s not a measurable, so how can you talk about it “flowing”?
“Heat flowing” is in fact a throw-back to the thoroughly debunked theory of a “caloric fluid” and predates the modern understanding of thermodynamics as a consequence of statistical mechanics (microscopic thermodynamics):
The proper term is “heat energy”, the corrected (cleaned up) statement is “the net exchange of heat energy is from a hotter body to a colder one.”
To be technical, this statement is a corrected version of the Clausius’s Principle, and can be shown to be a consequence of the 2nd law (dS/dt ≥ 0), but it is absolutely not the 2nd law, though sometimes it is erroneously and confusingly claimed to be a statement of the 2nd law, as has been done here.
In terms of the confusion on the part of JWR and other others, “heat energy” can be related via statistical mechanics to the mean kinetic energy of molecules (temperature being related to mean molecular energy via the Boltzman constant).
To unclutter things from outdated and confusing 19th century notation and principles, mean kinetic energy (heat energy) exchange occurs through the collision of molecules with each other (conduction), via thermal radiation (the exchange of a thermal photon between two molecules, which can occur nonlocally) and via the transport of molecules with a higher mean kinetic energy to a region with lower mean kinetic energy (convection).
Of these three mechanisms for the exchange of mean molecular kinetic energy, thermal radiation is a “nonlocal” effect in the sense that a given thermal photon can be exchanged between any two molecules, regardless of their kinetic energy or physical separation. Clausius’s Principle is not violated unless this results in a net mean positive exchange of heat energy from a region with a lower mean kinetic energy (lower temperature) to a region with a high mean kinetic energy (higher temperature), and only then when you sum over all three mechanisms for the exchange of mean molecular kinetic energy.
Clausius’s principle says nothing about whether a colder object can influence a warmer one, which of course it can, including via “backradiation” of thermal photons.
To try and frame this clearly, an individual molecule emitting a thermal photon cares nothing about the 2nd law of thermodynamics nor Clausius’s principle. Are the people who are saying back radiation is impossible suggesting that the molecule somehow “senses” that a region is hotter and that it isn’t allowed to transmit a thermal photon in that direction???
Such a suggestion of course is nonsense. but it is a necessary consequence of this mis-application of Clausius’s Principle suggested by JWF. If you can’t back-radiate, you can’t send a thermal photon from a colder region to a warmer region, and to make that happen, you would have to invoke some new physics, like sentient molecules or something of the like.
In reality, individual thermal photons get emitted from individual molecules without knowledge of the macroscopic large-scale distribution of matter surrounding it, when you average over molecules in a given volume, you end up with an isotropic radiation pattern (thermal photons are emitted with equal probability in all directions). Back-radiation of photons is actually a necessary consequence of the microscopic theory of thermodynamics, rather than being precluded by it.
(What prevents the net exchange of heat energy from a cooler body to a warmer one is that fact that the region at higher temperature—e.g., having larger mean kinetic energy per unit volume—will produce a larger radiative energy per unit time than the colder one, as governed by the Stefan-Boltzmann law.)
Steeptown: Everything at temperature is radiating in all directions; surely nobody argues with that. What is the argument about? We know that regardless of the radiation, net heat is in the direction of from hot to cold, unless we are doing work.
You are, when you endorsed JWF’s view that “backradiation -from cold air to warm earth surface- is not possible, according to the second law of thermodynamics.”
Try and stay consistent.
Carrick: Apologies. I was not endorsing JWF’s view that “backradiation – from cold air to warm earth surface – is not possible, according to the second law of thermodynamics.”
My apologies then too, Steeptown, for the misunderstanding.
Jeff Id #20: “If I (or someone else) has time, it would be useful to compare the probe-measured amount of CO2 induced warming on Venus at 1 bar of altitude (near space). This would probably be well above Venusian cloud formations in the lower high pressure regions and could give quite an interesting approximation of the net zero-feedback warming possible from CO2 on Earth.”
Although not a comparison of “probe-measured amount of CO2-induced warming on Venus at 1 bar of altitude”, Harry Dale Huffman did compare temperatures on both Earth and Venus at the 1 bar pressure level. His analysis at the following link is interesting, and maybe partially responsive to your comment.
http://theendofthemystery.blogspot.com/2010/11/venus-no-greenhouse-effect.html
Hi Carrick,
Just as a matter of historical background, I find it interesting that Pierre Prévost proposed the idea of a dynamic interchange of radiation between two bodies at equilibrium long before modern ideas about heat as energy became fashionable. He was a believer in the caloric theory but was still able to reach the conclusion that a hot body would continue to emit radiant caloric (calorique rayonnant) even though it might be absorbing an equal amount of caloric from another.
I have tracked down a digital version (in French) of his original book on the subject.
http://catalog.hathitrust.org/Record/001988683
If you jump to page 28 in the full view you can see where he talks about the dynamic equilibrium (équilibre mobile). My French is limited to a fifty year old “O” level(failed) so I would appreciate it if someone could translate the page for me.
My feeling is that he could not work out a mechanism that would prevent the outward flow of caloric from a hot body just because of the presence of another hot body some distance away. He had obviously not considered the possibility of “intelligent” caloric.
Steeptown #82,
I agree with his well written comment.
Lynn,
The ‘competent physicist’ of your link set the albedo of Earth and Venus as equal. The mistake destroyed the analysis but he also confirmed the number on wiki of 66C at 1 bar. This is much higher than I would have expected but atmospheres are complex things as Leonard Weinstein demonstrated in his comment above.
JWR said
June 4, 2011 at 1:15 pm
I think this sums up just how wrong this view of the world is.
Incidentally, I think that Carrick is wrong in suggesting that there is no way that back-radiation could not happen, in suggesting that it must occur because there no way the ‘sender’ molecule could be aware of the temperature of the ‘receiver’.
In practice this is true, but hypothetically is would be conceivable to design a universe where the ‘receiver’ molecule would be unable to receive a photon that required it to be in a lower energy state than it currently is, hence could only reflect back-radiation. In reality, the range of actual energies of individual molecules is such that there’s bound to be one that can accept the photon, despite the overall temperature being higher than the ‘sender’.
I hope I haven’t suggested a mechanism that JWR can latch onto.
Hi Steveta-Uk,
I agree with Carrick that the magic has to happen at the sender end rather than the receiver.
Take two plates facing each other in a vacuum with both at the same temperature. In your case the two senders will be radiating equal amounts towards each other but both will be reflecting rather than absorbing. Pretty soon the space in between will be awash with caloric or photons and there will be a continued energy loss from both the inner faces.
The only way to get a transfer of zero between either of the plates is if both the senders decide to stop radiating at all, having detected the existence of the other. Or of course we could go back to the old accepted view that both plates are simultaneously transmitting and absorbing equal amounts.
When I read some of the supposed physics that appears in this climate debate I am at a loss to decide whether the poster is simply confused, intentionally obtuse or a genius who has spotted something ordinary mortals cannot see. As I am often confused myself, confusion seems to be the most likely explanation.
Instead of proposing each other high school science experiments, look to the sites of Johnson:
http://claesjohnson.blogspot.com/search/label/2nd%20law%20of%20thermodynamics.
It deals with the impossibility of backradiation.
This side is more difficult for layman in the field.
On the other hand, and I repeat, look to the site of Postma:
http://www.ilovemycarbondioxide.com/pdf/Understanding_the_Atmosphere_Effect.pdf.
This site is written in a clear language, it is a must for those who want to understand how finally the lies of Gore, with the help of Pen State Man and other opportunistic people, will be abandoned by the taxpayers, in the near future.
JWR,
“It deals with the impossibility of backradiation.”
My friend, you and that web site are profoundly and completely wrong. Blackbody radiation is basic and well known physics. I suggest you actually try to learn about this subject; it would help you understand the substantive technical issues related to AGW…. and there are many, but the reality of blackbody radiation is not one of them. Focusing on nonsense (like claims that blackbody radiation is not real) only gives loony warmers straw men that are easy to knock down.
JWR,
How do you explain measured “back radiation” that occurs all the time in the field? This is a fairly standard measurement. One such as this
Click to access fig8-1.pdf
Most of this paper is pure bogus, and I’d flunk any first year undergrad who wrote this, let alone one apparently studying astronomy.
#90 Jeff Id:
“The ‘competent physicist’ of your link set the albedo of Earth and Venus as equal. The mistake destroyed the analysis…”
Huffman discussed how albedo doesn’t affect his analysis in the comments following his article. Did you not read the comments?
#90 Jeff Id:
“The ‘competent physicist’ of your link set the albedo of Earth and Venus as equal. The mistake destroyed the analysis…”
Huffman discussed how albedo doesn’t affect his analysis in the comments following his article. Did you not read the comments?
Are you really this gullible?
steveta_uk:
No, it has to be the sender molecule, as the photon contains no information imprinted on it about the mean kinetic energy of the region in which it was emitted.
Thermal radiation represents a continuous spectrum, with a large amount of overlap among molecules in a vertical layer of the atmosphere, so there simply is no way for the receiver molecule to “know” that he shouldn’t receive the photon. (Recall that the molecules in a region don’t all have the same velocity at a given temperature, but rather a the Maxwellian-like distribution, and further that the kinetic energy distributions of source and receiver also would generally also strongly overlap.)
The sender would have to know not only that it was transmitting in a “forbidden direction” but in addition the particular molecule that it was going to communicate with in advance. Because the transmission is between to spatially separated points, and done at the speed of light, and since the sender must know in advance whether the transmission is “allowed”, whatever mechanism the sender would use must also violate causality.
JWR:
It’s quite obvious you’ve adopted this position for political reasons, and this makes you a good example of how ideology makes smart people fall for stupid ideas.
Seriously, step off of your political soap opera (trying to prop yourself up by invoking the “lies of Gore” doesn’t help your case with scientists and engineers that frequent this board regardless of our views of that layman scientist/politician) and try visualizing the science…imagine a thermal photon being emitted by a source molecule and absorbed by a receiver one, then ask yourself how back radiation could actually be impossible.
Chris:
I’m afraid I’d have to show some “tough love” and send them packing.
Jorge thanks for the historical reference. I’ll admit I was unaware that they were already discussing radiative heat exchange in those days.
Unfortunately (other than a few choice words I’ve learned for communicating with rude Parisians) I know no French.
I should mention that Science of Doom had a nice expose of what happens when you bring a colder body into proximity with a warmer one. I believe that this is the proper link.
Carrick said
…”Jorge thanks for the historical reference. I’ll admit I was unaware that they were already discussing radiative heat exchange in those days.”
The discussion that Pierre Prévost contributed to was to explain the historic Pictet experiment.
This concerned the “radiation of cold” quite the opposite tendency to Jeff Ids post.
Prévost explained the drop in the warmer sensor or the introduction of the colder object as a dynamical exchange(two way) of radiation
Jeff,
It seems that you agree that the high temperature on Venus is due primarily to a strong CO2 greenhouse effect (few hundred deg) and secondarily (?) to the high surface pressure (the ~80 deg number that was mentioned upthread).
If so, then I don’t understand the beef you have with Chris’ take, where he uses Venus as an example that shows that CO2 is a greenhouse gas.
Or is this just an argument for sake of the argument?
The mix up with definitions of radiation, energy and heat has led to great confusion and and a considerable amount of intellectual mischief.
For the record in an interaction between a higher temperature object and a lower temperature object;
Radiation exchange is a two way process
Energy exchange is a two way process
Heat exchange is a one way process always from the higher temperature to the lower temperature.
For instance JWR thinks the Postma paper deals with the impossibility of backradiation.
http://www.ilovemycarbondioxide.com/pdf/Understanding_the_Atmosphere_Effect.pdf.
I suggest that JWR is confused and should reread Postma who says no such thing.
This confusion opens the door for AGW propagandists like Chris Colose.
Chris Colose is one of the co-authors of the by now infamous;
Comment on ‘Falsification Of the atmospheric CO2 greenhouse effects within the frame Of Physics’ by Joshua B. Halpern, Chistopher M. Colose, Chris Ho-Stuart, Joel D. Shore, Arthur P. Smith, Jorg Zimmermann.
Click to access halpern_etal_2010.pdf
The main point of Halpern paper was to say that G&T had said that colder bodies could not radiate to warmer bodies.
This despite several diagrams and formulas in the G&T paper showing a two way interaction.
This must be the most embarrassing paper in history as it attacks G&T for things they didn’t say.
All G&T had to say in reply was “where did we say that”
The Halpern paper was a collection of errors in particular they were deeply confused on the topic of the nature of heat.
“Falsification Of the atmospheric CO2 greenhouse effects within the frame Of Physics” by Gerhard Gerlich and Ralf D. Tscheuschner; International Journal of Modern Physics B, Vol. 23, No. 3 (2009) pages 275-364.
Click to access 0707.1161v4.pdf
Bryan,
Thank you for the mention of Pictet´s experiment. I did not know of this but it certainly is fascinating as an example of the empiricism that seemed to dominate in those days.
This is an interesting link about the ideas that were circulating at that time.
Click to access Pictet’s%20experiment.pdf
Perhaps I should have another look at G&T. I read an early version. There did not seem to be anything actually wrong in it but nothing seemed to to illuminate the real controversies that exist.
Bart,
I object to its comparison to Earth as a scare tactic in general. That’s all.
101 Bart,
You have that backward. The high temperature of Venus DOES requires some greenhouse gas to happen (see my comments at #1), but once even a modest amount of greenhouse gas is present, it is the large thickness of the massive atmosphere that dominates the high temperature increase. If Venus were 10% CO2 rather than 96%, the temperature would be only a few 10’s of degrees different (smaller if N2 were substituted for the lost CO2, both because the Cp of N2 is larger, and due to some drop in outgoing radiation altitude). However, if the gas selected had an average Cp higher (i.e., replacing the lower CO2 concentration with a gas like Argon (which is not a greenhouse gas and is similar density as CO2), the temperature would be HIGHER, since the lapse rate increase would dominate the drop in outgoing radiation altitude.
Bart:
Probably not (I’ll let Jeff speak for himself), but for a scientist that is never a bad thing. This has been an interesting set of threads.
Bryan:
Could you expand on this? I haven’t read Halpern et al (nor I admit G&T), and it would be interesting to hear your slant on it.
If I need to buy popcorn and cola before reading your comments, please warn me now.
Hi Carrick
I have read your posts elsewhere and you should be able to spot the Halpern et al errors almost instantly.
On page 1316 0f their comment paper they refer to HEAT flowing from a
colder disk to a hotter disk.
Not only that, they then go on to say that if G&T deny this they are saying that they(G&T) say that radiation cannot travel from a colder to a hotter surface.
There are a number of other errors but these two in a physics journal are unforgivable.
Bryan,
Please try to actually read G&T as well as our paper. Both full texts are easily accessible. The whole point of G&T is that the greenhouse effect violates simple thermodynamics, an absolutely absurd argument. They even think a pot of water on a stove is a “housewife proof” against the greenhouse effect, because the bottom of a pot gets hotter without water in it than with water in it. The gullibility that it takes to buy this is amazing, and very revealing about either your ignorance or your attempt to trick people.
Chris Colose says
Bryan,…”Please try to actually read G&T as well as our paper. Both full texts are easily accessible.”…
Yes Ive posted both above at 102.
Chris Colose says
…”The whole point of G&T is that the greenhouse effect violates simple thermodynamics, an absolutely absurd argument.”
Why then, have several Physics professors come to the conclusion that the CO2 induced greenhouse theory is false?
What G&T say is that SOME versions of the greenhouse theory violate simple thermodynamics.
Your Halpern et al paper paper then provided the very proof of the G&T claim!
On page 1316 of your comment paper you refer to HEAT flowing from a
colder disk to a hotter disk.
Chris perhaps you did not notice that this implies a violation of the second law.
Certainly Arthur Smith and Joel Shore as professional physicists must now be very embarrassed by this fundamental slip up.
Chris Colose says
..”They even think a pot of water on a stove is a “housewife proof” against the greenhouse effect, because the bottom of a pot gets hotter without water in it than with water in it.”…
Remember that the some crude versions of the Greenhouse Theory claim a 33K heating effect.
Bryan, “Why then, have several Physics professors come to the conclusion that the CO2 induced greenhouse theory is false?”
Because they made conceptual errors, probably. Seriously, that is the most plausible explanation.
In terms of heat energy being exchanged from a colder body to a warmer one, again this isn’t 2nd law directly, but Clausius’s Principle, which is a consequence of the 2nd law under certain circumstances (such as no work is done, heat pumps move heat energy from colder objects to warmer ones all of the time).
It’s also important to remember that “S” is a classic concept, it is difficult to apply it to e.g. curved space time (black holes may violate the 2nd law for example, though there is debate whether or not this is true…conservation of energy is also impossible in a curved space time) and there are coherent quantum mechanical effects that may also violate certain statements of the 2nd law. (I’d have to dig these out, it’s been a while since I’ve read about this.)
What G&T say is that SOME versions of the greenhouse theory violate simple thermodynamics.
Yes, they took an awful lot of time to shoot down straw man versions of the greenhouse effect by various sources, including “anonymous” sources. Apparently they think that exposing flaws in popular versions of the greenhouse effect meant for the lay public actually contributes to science. Even in their disproofs, they were still wrong a number of times. And they are still wrong about the greenhouse effect violating the second law…
Why then, have several Physics professors come to the conclusion that the CO2 induced greenhouse theory is false?
Why did they have to publish it in a rather irrelevant journal, and why has no one in the academic community taken them seriously since then? It’s for the same reason that Grant Petty, professor of Atmospheric Thermodynamics & Radiation at UW-Madison, said that after reading their “rebuttal” he was fully convinced they were cranks and I should waste no further time on them.
Why should any physics student out of undergrad be able to show why they are wrong? Because they are trained to not be as gullible as you.
Chris C
I now appreciate that you have some difficulty with reading.
This is why your name is on a document accusing G&T of saying that a colder object could not radiate to a warmer object when they said no such thing.
Several diagrams and formulas showing a two way interaction seem to have escaped your attention.
You also seem to want to stand by HEAT moving spontaneously from a colder to a higher temperature object.
Thus confirming the G&T statement that some greenhouse theories advocate propositions that are impossible according to the second law.
So now someone that cannot read and has never been anywhere near a thermodynamics course feels he can judge that G&T
” publish it in a rather irrelevant journal”
You think the “cut and paste” Mann hockey stick paper is the level of sophistication and integrity that climate science upholds and that perhaps a physics journal does not have such high standards?
Bryan,
Since I am absolutely convinced you have not understood (or read) a word of G&T or our rebuttal, let me ask you this: What contribution do you think G&T makes to the scientific community? i.e., if I study atmospheric radiation and build radiative transfer models or devices to measure spectra, what does G&T do for me?
Chris Colose said
……”Since I am absolutely convinced you have not understood (or read) a word of G&T or our rebuttal”…..
In fact I have read and understood both several times.
Chris Colose said
……………….”let me ask you this: What contribution do you think G&T makes to the scientific community …… what does G&T do for me?”……
Well it appears that you would need to go to an optician to help with your reading problems.
You don’t require two theoretical physicists to help you with that.
Its quite obvious that you need to study basic thermodynamics.
Look up the definitions of HEAT, WORK, ENERGY and make sure you understand them.
Work through the Carnot Cycle to see how these definitions relate to the Second Law of Thermodynamics.
Until you do that I would avoid making any statements about thermodynamics as they just make you look silly.
G&T made their contribution to the climate debate by analysing the available popular versions of the greenhouse theory from within the framework of physics.
Anyone who has studied thermodynamics to a reasonable level will find themselves in agreement with their conclusions.
Anyone who has studied thermodynamics to a reasonable level will find themselves in agreement with their conclusions.
Anyone except NASA, the Royal Society and every other scientific community on the planet.
(shrug)
Yet there would be quite a few bloggers who had “studied thermodynamics to a reasonable level” that would very likely agree with their conclusions.
Why then, have several Physics professors come to the conclusion that the CO2 induced greenhouse theory is false?
Old age? Maybe they made a mistake? Maybe they are in denial?
Science has no prophets.
Science is not embodied in individuals making pronouncements from “on high” even if they are (hushed whisper) Physics professors.
Only the work matters.
Evolution vs. Creationism:Experts vs. Scientists-Peer Review
Cedric Katesby
Creationism is a speciality of Mann.
Climate “Science” has more then enough “Creationism” to be taken seriously.
Have you heard about the one where the “greenhouse effect ” produces a 33K heating effect.
…..”Yet there would be quite a few bloggers who had “studied thermodynamics to a reasonable level” that would very likely agree with their conclusions.”……
……”Only the work matters. ” I agree
Both articles are available at 103 above.
Perhaps Cedric you will enlighten us with a rational criticism of some points in the G&T paper.
I think you will agree with me that the Halpern et al comments are a dismal failure in that regard.
However I think you are more of a “hit and run” commentator.
Prove me wrong.
You are just making bland assertions.
Anyone who has studied thermodynamics to a reasonable level will find themselves in agreement with their conclusions.
Then how do you explain that NASA does not agree with you?
Is it some sort of a conspiracy?
Why then, have several Physics professors come to the conclusion that the CO2 induced greenhouse theory is false?
Why are you bedazzled by “several Physics professors”? You have all the scientific communities on the planet at your fingertips.
Bryan has yet to explain what is wrong with the temperature or entropy calculations in The Three Body Problem.
I have asked him when I posted the original article and in various blogs around the internet where he continues his claims.
It should be simple. If the inappropriately-named “greenhouse” theory violates the 2nd law of thermodynamics then he should have long ago done the entropy calculation to prove this.
The sun warms the planet. The atmosphere changes the rate at which energy leaves the planet. Adding the atmosphere increases the surface temperature and yet the entropy still increases. All demonstrated in the article. Simple stuff.
Bryan never mentions entropy. Bryan hasn’t suggested an alternative equation for entropy, hasn’t done the simple calculations to work out the entropy change in that example and yet has the chutzpah to keep claiming the “greenhouse” effect violates the second law.
It has been many months and Bryan either can’t do simple calculations, or has, and is too embarrassed to admit he can’t find a fault in it.
More time perhaps to do simple division? I don’t think so. More time to find the right equation for change in entropy? Surely not.
So I hereby claim that Bryan has conceded the point by default.
Cedric Katesby says
“Why are you bedazzled by “several Physics professors”? You have all the scientific communities on the planet at your fingertips.”
Myth
Cedric obviously believes that 99% of scientists and all the world academies have studied the “greenhouse theory” in depth and have come to the conclusion that it is as robust as the second law of thermodynamics.
Reality
“There is a structural flaw in the IPCC. Far from being the distillation of the work of 2,500 scientists to produce a consensus, there is a core of 40-50 at its centre who are closely related, as colleagues, pupils, teachers, reviewers of each other’s work. The IPCC has failed to operate a rigorous conflicts of interest policy under which such relationships would be disclosed. It has managed to define a very simple AGW message and has sought to prevent alternative voices from being heard. The IAC criticised a tendency not to give sufficient weight to alternative views.”
Lord Turnbull – Former head of the British Civil service.
The climategate e-mails confirmed this shocking anti scientific behaviour.
http://judithcurry.com/2011/06/01/making-the-lukewarmer-case/
Perhaps Cedric you will enlighten us with a rational criticism of some points in the G&T paper.
I’m still waiting!
You were the one that brought up “several Physics professors”, not me.
Why then, have several Physics professors come to the conclusion that the CO2 induced greenhouse theory is false?
There could be several reasons. All of them mundane.
Anyone who has studied thermodynamics to a reasonable level will find themselves in agreement with their conclusions.
Not according to the scientists at NASA.
Not according to the Royal Society.
All due respect to the eminent Lord, of course, but when I want to find out if NASA is on board with AGW then I will…(hushed gasp)…go to their website myself.
It’s all there in plain English.
All scientific communities on the planet are on board with AGW. There are no exceptions.
This is easy to check by looking at a random selection of their websites.
(AGU, American Physical Society, USGS, CSIRO, British Antarctic Survey, etc.)
They are all good.
Yet you claim that…”Anyone who has studied thermodynamics to a reasonable level will find themselves in agreement with their conclusions.“.
What gives?
How do you explain that NASA does not agree with you?
Is it some sort of a conspiracy?
Science of Doom (aka 7th Cavelry) rides in to rescue Chris Colose.
Chris and the others from Halpern et al are of the opinion that heat can travel spontaneously from a cold surface to a surface at a higher temperature.
Which is a two body problem so SoD stick to the topic.
Perhaps you yourself are of a similar disposition and you ask for an entropy calculation as proof
Two objects A and B exchange heat Q in a closed system.
We will not initially say if temperature Ta is bigger than Tb, however to get started say the heat Q moves from A to B in time dt
Entropy lost by A = dSa = -Qdt/Ta
Entropy gained by by B = dSb = Qdt/Tb
The second law tells us dSa+dSb > 0
-Qdt/Ta + Qdt/Tb > 0
This is only true if Ta > Tb
In other words in (the second law of thermodynamics) Heat only flows spontaneously from a higher temperature object to a lower temperature object never the reverse
Cedric Katesby said “Not according to the scientists at NASA.”
Well Cedric as a big fan of Nasa, you will appreciate this link!
Not only that I am offering a major prize if you can spot the part played by radiative transfer in the narative.
http://rst.gsfc.nasa.gov/Sect14/Sect14_1b.html
Wonderful to finally see Bryan produce an entropy calculation for the Two Body Problem.
The atmospheric “greenhouse” effect is a Three Body Problem. The sun, the earth and the atmosphere.
As I said in that article – The Three Body Problem:
“Very quickly, to “warm everyone up”, and to once again state the basics – if we have two bodies in a closed system, and body A is at temperature 80°C and body B is at 10°C, then over a period of time both will end up at the same temperature somewhere between 10°C and 80°C. It is impossible, for example, for body A to end up at 100°C and body B at 0°C.
Everyone is in agreement on this point..”
Bryan, desperate to avoid facing up to the obvious point that he still hasn’t done his homework from Nov 2010, says:
[Claims about what other people think] “.. Which is a two body problem so SoD stick to the topic.”
Proposition Bryan
What Bryan is saying here is that he believes / wants to believe / wants everyone else to believe that all who accept the inappropriately-named “greenhouse” effect think this:
– two bodies spontaneously move apart in temperature
We will call this Proposition Bryan. No one does believe Proposition Bryan, but it is a useful Red Herring to help Bryan avoid His Homework.
I have asked Bryan to deal with the real proposition, the Three Body Problem, and instead he proposes Proposition Bryan each time. Usually by reference to the Carnot Cycle that everyone understands and agrees with. Now, finally, by entropy calculations for a 2 body problem.
So Bryan has conceded the point by default. No doubt we will continue to see Proposition Bryan in its many forms resurface over the coming months. And no entropy calculations for the 3-body problem.
Well Cedric as a big fan of Nasa, you will appreciate this link!
I’d appreciate it even more if you could defend your own words rather than abandon them.
Focus.
Why then, have several Physics professors come to the conclusion that the CO2 induced greenhouse theory is false?
Old age? Maybe they made a mistake? Maybe they are in denial?
Science has no prophets.
Science is not embodied in individuals making pronouncements from “on high” even if they are (hushed whisper) Physics professors.
All scientific communities on the planet are on board with AGW. There are no exceptions.
This is easy to check by looking at a random selection of their websites.
(AGU, American Physical Society, USGS, CSIRO, British Antarctic Survey, etc.)
They are all good.
Yet you claim that…”Anyone who has studied thermodynamics to a reasonable level will find themselves in agreement with their conclusions.“.
What gives?
How do you explain that NASA does not agree with you?
Is it some sort of a conspiracy?
SoD typifies a trait all too common with IPCC supporters.
Its known as the “butterfly communication effect”
It might even be related to the Heisenberg Uncertainty Principle but who knows?
However the sufferers have a pronounced inability to stay on topic.
We were examining the Halpern et al paper concerning a two body problem.
A higher temperature surface and a surface at a lower temperature.
But no – SoD doesn’t want to talk about that – he wants to talk about a three body problem!
However I think all are agreed that during daytime the energy path is from the Sun to the Earth system.(A two body problem)
At night where the backradiation enthusiasts claim most of a “greenhouse effect” we again have a two body system.
The atmosphere and the Earth surface.
Once we have reached agreement on the two body problem then perhaps we can perhaps discuss SoDs three body scenario.
But SoD you now have your chance prove to a sceptical audience;
Does heat flow spontaneously from a colder object to a higher temperature object?
Cedric Katesby
When I clicked on your name I was directed to a site devoted to…….
James Randi
Now as it happens I am a big fan of his.
In fact that was where I got the idea of offering a prize to anyone who could find the “greenhouse effect” in the NASA description of the lapse rates of the troposphere.
It must be there somewhere?
Shouldn’t it!
James Randi, crazy guy, crazy name but is it real!
“You can’t fix stupid”- Ron White
Bryan,
Do you mean “net”, or no “net”.
#130, Here we go again.
Jeff, they’ve got a million of them.
Carrick
I have always understood that heat transfer is only from a higher temperature object to a lower temperature object .
Which part of that do you not understand?
Bryan, I asked a pretty specific question. You entirely failed to answer it, which I take to mean either you don’t want to be more specific (because that would involve sticking your neck out further) or you don’t understand the importance of the word “net”.
The operative word is here “net”.
In the statement “eat transfer is only from a higher temperature object to a lower temperature object ,” “only” is wrong if you don’t that word “net”, and even if you use the word “net” you still have to say in “the absence of work” done on the system (heat pumps move heat energy from colder objects to warm ones, that’s the definition).
Anyway, let’s consider two bricks in thermal, physical contact with each other, one’s at a higher temperature, the others at a lower.
Why the exchange of heat energy occurs in both directions is pretty simple to understand from the underlying kinetic theory…a molecule which is part of the ensemble of molecules in the lower temperature brick (which has a lower mean kinetic energy) can collide with a molecule from the ensemble of molecules in the higher temperature brick (which has a higher mean kinetic energy), and impart net momentum on the higher energy molecule.
Technically heat energy gets exchanged both ways, it’s just that the hotter object exchanges more heat energy to the cold object than the cold one does to the hotter object. So the net transfer of energy will be from the hotter object to the colder one.
This same argument holds mutatis mutandis for the case where the two bricks not in contact and in a vacuum surrounded by a perfectly insulating container. Thermal photons will get exchanged from the colder object to the warmer one as well as from the warmer one to the cooler one.
Carrick
I posted this earlier
The mix up with definitions of radiation, energy and heat has led to great confusion and and a considerable amount of intellectual mischief.
For the record in an interaction between a higher temperature object and a lower temperature object;
Radiation exchange is a two way process
Energy exchange is a two way process
Heat exchange is a one way process always from the higher temperature to the lower temperature.
Heat is energy but not all energy is heat.
The thermodynamic meaning of HEAT means that as it is transferred it has the capacity to do WORK in the given situation.
Between the high temperature reservoir and the low temperature reservoir you can have a transducer that will turn some of the heat energy into driving pistons etc.
The energy from the colder reservoir has no such capacity and so cannot be described as HEAT.
Read over some thermodynamic chapters from a physics textbook.
Particularly the analysis behind the Carnot Cycle
Bryan, from my perspective, the quantity “heat” a made up term by classic thermodynamicists (e.g., Clerk Maxwell in his Theory of Heat) who were mixed up over how heat energy got exchanged, and thought it involved the exchange of a caloric fluid between the two bodies. (Thus heat exchange was like water from flowing a higher gravitational potential to a lower gravitational potential).
I don’t believe “heat” as a physical concept has any place used in this context in modern science, it serves no positive role and simply leads to confusion because almost no two people use the same exact language to describe it.
There is such a thing as “heat energy”, it has units of Joules, and it is proportional to the mean kinetic energy of the ensemble, and it is directly mesurable..
The available heat energy to do work, what people would have called “heat” about 140 years ago, and you apparently still do, depends on the experimental configuration… so it is not an internal property of the object, and thus not an intrinsic property, or measurable, of an object.
I think we’d all be better off leaving out ill-defined language that arose from long-ago discarded theories. When people talk about “heat” and “heat exchange” it’s almost like they need to discuss whose textbook or course they learned the concept from.
(I’ll leave the rant on the abuse of math used in conventional thermodynamics to another comment.)
Bryan:
Of course I obviously have. Mine are a bit more up-to-date than yours apparently, and denigrate the use of the word “heat”. (In keeping with the “whose textbook” context 😉 )
A good source for my view of the word heat may be found on pages 24-28 of Bohren and Albrect, Atmospheric Thermodynamics.
You can find this section from their index, under the entry, “Heat, nonexistence of, 24-28.”
Here’s another reference: “Heat is not a noun.” by Robert Rommer.
First paragraph:
Carrick said
A good source for my view of the word heat may be found on pages 24-28 of Bohren and Albrect, Atmospheric Thermodynamics.
You can find this section from their index, under the entry, “Heat, nonexistence of, 24-28.”
…………………………………………………………….
Climate Science textbooks are the last place I would look to get a definition of heat.
…………………………………………………………….
Here are some more reliable sources
From University Physics by Harris Benson page 382
Modern definition of Heat
Heat is energy transferred between two bodies as a consequence of a difference in temperature between them.
University Physics Young and Freedman
Energy transfer that takes place sole because of a temperature difference is called heat flow or heat flow transfer and energy transferred in this way is called heat page 470
Heat always flows from a hot body to a cooler body never the reverse. pg 559
When Feynman finished his thermodynamics sections in the famous 3 volume lectures he recommended interested readers who wanted to take the matter further only one book.
The book he recommended was the ultra orthodox Heat and Thermodynamics by Zamansky.
Zemansky comments on radiation on page 105
….the difference between the thermal radiation which is absorbed and that which is radiated is called heat.
Bryan, that isn’t a climate text book, but an atmospheric science one. In science, a thing is true regardless of who said it. I think they make good points. I consider Feymann and Zamansky very old school on this question.
I don’t doubt there are people who hold to your particular definition of “heat”. The fact that two people with thermodynamics training would even be discussing the word heat at all suggests it may have limited utility.
“Net heat energy exchanged” has an exact, unambiguous meaning, I think neither of us would have any trouble understanding what that meant.
The questions I bring up are a) how uniform or agreed to is that is, b) whether the semantics associated with the noun “heat” have any explanatory utility.
(And by the way, the word “flow” used by Halpern et al has absolutely no business being used, there is no “flow” involved, it is a complete throwback to outmoded ideas.)
But having said this, at least I understand the point of your objection, now that I know exactly how you meant the term “heat” to be interpreted.
(Waiting on data to transfer…not just goofing off)
To show just how completely garbled up the language can get, here’s from the McGraw-Hill Science & Technology Encyclopedia:
Carrick said
” I consider Feymann and Zamansky very old school on this question”…….. (on the definition of heat)
I was not aware of any significant developments in thermodynamics in the last 50 years that make these definitions redundant.
I think that the softening and equivocation of termanology is part of the problem.
That problem is Climate Science and the lack of rigour where just about any opinion is as good as the next.
………..“Net heat energy exchanged” has an exact, unambiguous meaning, I think neither of us would have any trouble understanding what that meant.”………..
Do we?
I would understand that the person using the phrase was thinking that heat can be transferred spontaneously from a low temperature object to a higher temperature object as long as a little more heat went the other way.
I would also think that this would imply a violation of the second law however unintentionally.
I would then have to seek clarification from the person as to what exactly they meant by the word heat.
The Carnot Cycle is not some ancient anachronism.
Its the starting line for engineers chemists and physicists who want to understand the second law and how machines and processes occur in the real world.
The loose vocabulary used in climate science is thankfully not tolerated elsewhere.
You would not find the use of the phrase in a physics publication of sufficient standing.
140 – Bryan, please can you clarify your closing reference:
/”The book he recommended was the ultra orthodox Heat and Thermodynamics by Zamansky.
Zemansky comments on radiation on page 105
….the difference between the thermal radiation which is absorbed and that which is radiated is called heat.”/
Is the bit after the “…” a quote from p105, and is it one you approve of?
curious said
Zemansky comments on radiation on page 105
….the difference between the thermal radiation which is absorbed and that which is radiated is called heat.”/
Is the bit after the “…” a quote from p105, and is it one you approve of?
Yes!
ok!
Bryan:
Then you haven’t been keeping up with literature, nor have you been reading any of the links or excerpts I’ve quoted.
Only if you have trouble understanding what heat energy is, and are conflating heat energy with your particular definition of heat. Heat energy can and does get transmitted in both directions, as I’ve pointed out several times now.
As far as I’m concerned, we’ve both stated what we’ve think, I happen think I’ve substantiated my views far better than you have (you have mostly name-called any reference that dissents from your particular views), so this is a good time for this discussion to wind down.
Laterz.
#97 Chris Colose:
“Are you really this gullible?”
Did you read Huffman’s analysis, and the following comments? Did you carefully think about the ramifications of his analysis for your pet gris gris?
I said
I was not aware of any significant developments in thermodynamics in the last 50 years that make these definitions redundant.
Carrick said
Then you haven’t been keeping up with literature, nor have you been reading any of the links or excerpts I’ve quoted.
I said ….significant developments in thermodynamics …rather than some educationalist who has a problem with definitions
Carrick said
Heat energy can and does get transmitted in both directions, as I’ve pointed out several times now.
I said
I would understand that the person using the phrase was thinking that heat can be transferred spontaneously from a low temperature object to a higher temperature object as long as a little more heat went the other way.
Your understanding is that heat can travel spontaneously from a colder body to a higher temperature body, violates the second law.
Now if you had said thermal energy you would be ok.
Homework ..for Carrick Find the difference between heat and thermal energy
Because if you repeated this in a physics exam you would fail the question.
I think instead of merely repeating your mistake you should get a physics textbook work through the Carnot Cycle and then thank me for a patience in explaining the obvious to you.
To paraphrase Jeff Id via the Cohn brothers “Clausius abides”
well, I now understand what Bryan is talking about:
1. Body A has temperature Ta
2. Body B has temperature Tb
3. Ta> Tb
4. A radiates ENERGY to body B and vice versa
5. HEAT ENERGY or HEAT gain/loss is the difference between the energy radiated and the radiation absorbed
6. Hence, in accordance with the 2nd law of thermodynamics, HEAT or HEAT ENERGY flows from body A to body B.
7. Conclusions:
(a)”Heat is the net transfer of heat energy” is at best a tautology and is meaningless
(b)HEAT is energy but not all energy is heat (refer to 5)
Lynn,
I read the comments after you said I should. They were completely unconvincing.
An example is a mirror. If you place a mirror in the sun, a portion of the energy is reflected in the magnetic fields of the electrons of the reflective metal while another portion of the spectrum is absorbed. The absorbed light adds to the net energy of the mirror, the reflected energy does not.
Your physicist’s claim is that the reflected energy still adds to the Venusian mirror and then goes off into space to add that same energy again somewhere else. Conservation of energy is violated. Albedo cannot be ignored in planetary heating.
MarkL….. yes you’ve got it
Look at the deliberate way Zemanski deals with radiative transfer.
….the difference between the thermal radiation which is absorbed and that which is radiated is called heat.
(Zemansky comments on radiation, page 105 of Textbook Heat and Thermodynamics.)
Thus radiative transfer like conductive and convective transfer will have heat transfer only from a higher temperature to a lower temperature.
Another way to look at it is that heat is that part of the thermal energy interchange that is available to do work.
Bryan —
So would wikipedia: “Heat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another.” Not that wikipedia is the bastion of all that is correct, but this is not a particularly controversial statement.
I believe he is mocking your definition, which you’ve set up in such a way that is no longer has any relation to GHGs. Look back at #4…that is the relevant part for GHGs.
Bryan:
Now you’re just being a dumb=ass, most of the people I’ve referenced aren’t educationalists, but practitioners. Bohren and Albrecht for example do real-world research that includes thermodynamics (meteorology and atmospheric sciences to be exact), while I suspect you do zero.
I never said heat, I said heat energy. Heat energy is actually a synonym for thermal energy, for the physics challenged among us (which does include Bryan).
Only if the instructor were about as completely ignorant as you are about the topic. In which case, I should probably be teaching him. (You’ve already demonstrated that you think you are the wisest person in the room, making you unteachable, you’d flunk regardless of who taught you, unless it was a regurgitation of that introductory course you took.)
There’s a lot more to the field than the Carnot Cycle. You actually might want to learn some of it, one day.
When one writes down a set of equations to describe a problem, Clausius’s Principle isn’t something you explicitly write down. It may “abide” but it’s practically useless from a quantitative perspective. In fact, even dS/dt ≥ 0 is never explicitly used.
Here’s an example, we write down a state equation, let’s say the ideal gas law:
P = rho R T
we write down a dynamical law, such as Navier Stokes (the continuum equivalent to F=ma)
We write down an equation for entropy. E.g., for a gas with a temperature indiependent specific heat per unit mass at constant pressure, we can write:
S = cp log(T) – R log(P) + S0
We also need some form of continuity equation. For a stationary fluid we might write:
d rho/dt + grad . (rho v) = 0
We also need one or more equations describing heat energy transfer among the bodies, and so forth.
Inequalities like dS/dt ≥ 0 are upheld either by assuming entropy is conserved in the process (in which case the process is reversible) or by including a source for entropy (e.g., combustion).
What prevents dS/dt < 0 is the fact that all entropy sources are ≥ 0.
Clausius's principle, nor Bryan's 1st year physics version of "heat" ever play a role here.
Almost any real world problem involves derivatives with respect to time, and we deal with power, not energy. When you install a heat pump for your how, you need to know how much power it draws. Not some meaningless thermodynamic quantity useful for illustrating thermodynamics to noobs
As an exercise for people who are curious, they could investigate the historical reasons why thermodynamics originally didn't include an explicit time dependence. And why any modern treatment does.
Troyca, just to be clear, “heat energy” and “thermal energy” are synonymous terms. Bryan apparently thinks I mix up “heat” with “heat energy” in spite of how many times I’ve said otherwise.
Carrick
Your pride must be hurt to occasion such an outburst.
Do you think that spouting out formulas like a form of verbal diarrhea might impress some gullible onlooker.
Its like shaking a can and out comes all the pathetic contents.
You know you are wrong and like a little child you throw the rattle out of the pram.
Its pathetic.
Any objective person reading the exchange knows you lost.
But to lose the plot because of it, shows a truly infantile disposition.
Bryan, I was giving an illustration of how thermodynamics gets applied.
I’m not surprised you were not able to follow it.
You not understanding the difference between educators and practitioners is not lost on me.
LOL.
Anybody reading the exchange realizes you haven’t’ lost it, you never had it.
troyca
“your definition, which you’ve set up in such a way that is no longer has any relation to GHGs. Look back at #4…that is the relevant part for GHGs.”
Whats your obsession with greenhouse gases?
The discussion was about heat transfer in a general sense.
The radiative exchange between a higher temperature object and a lower temperature object is perhaps what you are referring to.
Look at the deliberate way Zemanski deals with radiative transfer.
….the difference between the thermal radiation which is absorbed and that which is radiated is called heat.
(Zemansky comments on radiation, page 105 of Textbook Heat and Thermodynamics.)
Thus radiative transfer like conductive and convective transfer will have heat transfer only from a higher temperature to a lower temperature.
Another way to look at it is that heat is that part of the thermal energy interchange that is available to do work.
Of course geniuses like Carrick think Zemanski is……. so yesterday.
Carrick comes up with his personal definitions of heat, heat energy, work, radiation, thermal radiation and so on.
So by equivocation of definitions, Carrick is always right because he makes up his definitions on the hoof.
The definitions like Alice in Wonderland is just what he wants them to be.
So in Carricks world heat can travel spontaneously from a colder surface to a higher temperature surface.
The laws of thermodynamics no longer apply.
But does anyone other than Carrick live in his world.
Does anyone even care what he thinks!
Bryan:
You can continue to spout this idiocy as much as you like, but what I said was heat energy, a synonym for thermal energy can travel from colder surfaces to warmer surfaces. At some point, when you continue to misstate what I have said, after being corrected, it stops just being an error in paraphrasing on your part and turns into a lie.
I suppose you like your dated reference book because it was on sale for $4.
Surprisingly, not only has thermodynamics not come to a screeching halt since then, it is still an active area of research, and indeed there are many questions that have been answered since the publication of (noobie problems like the Carnot Cycle being a counter example).
The people here who know the field “get this” and I think like me most of them are satisfied at this point that you’re just another poser.
Brian,
If you want to have a clear site, on thermodynamics, on the second law, on the non existance of back radiation: see Claes Johnson, from the University of Stockholm:
http://claesjohnson.blogspot.com/search/label/2nd%20law%20of%20thermodynamics
It can be summarized as:
Stefan-Bolzmann derived from the Planck equations the radiation from a surface at temperature T towards outer space at temperature 0 K, as q = sigma*T^4.
The correct way of writing the Stefan-Bolzmann law for the radiation heat transfer between two surfaces , surface 1 with temperature T1 and surface 2 with temperature T2,
with q12 the flow from heat, or thermal energy, from surface 1 to 2 , and q21 the flow from heat from surface 2 to surface 1:.
if T1>T2 then q12 = sigma* (T1^4 – T2^4) , q21 = 0
and
if T2>T1 then q21 = sigma* (T2^4 – T1^4) , q12 = 0
and
if T1 == T2 then q12 = 0, q21 = 0.
As Johnson says, for a lot of situations, in partucular for situations of 100% absorption screens, not only one, but also 2,3,4….. , the result will be the same.
But not for a staple of semi-transparant layers!
You will get the answers from Jeff Id. as he did with the site of Postma, not to read Johnson, because indeed Johnson claims that back radiation does not exist and that CO2 is the reason for climate variations.
But let the bloggers find out themselves what Johnson says in 9 articles on thermodynamics and the non-existance of back radiation.
As concerns the measurements of back radiation, there seems to be a semantic error.
If one calls the algebraic expression “sigma*T2^4” (for a cloud at temperature T2) the “back radiation” of such a cloud, then the error has been identified.
And how do you measure the algebraic term sigma*T2^4?.
By measuring T2?
Or by a pyrometer, which is also based on the measuring of T2 based on radiation to a surface, within the pyrometer, with a temperature made smaller than T2.
A pyrometer with a absorbing surface cooled by means of refrigerator with a varying capacity until the measuring surface is not changing anymore.
One claims that the absorbing plate has then the temperature of the cloud, T2 , and the algebraic term sigma*T2^4 is called the “back radiation”.
This explains also the difficulty of measuring the temperature T2 of a cloud which is lower than the environmental temperature of the pyrometer, even under the surcumstances on earth.
Indeed a lot more measyurements are available for measurements from satellites of the radiation of the warmer earth, despite the fact that such measurements have to be done remotely. Why?
Because when you want to measure in a colder environment the radiation of a warm object at a distance, you have to start to heat the absorbing surface of the pyrometer, by a battery charged by solar panels, until there is equilibrium.
And “controled heating” in a device in a satellite is a lot easier than “controled cooling” in a device on earth.
I would like to thank for the post concerning the experiments of Pictet, some 200 years ago, of which I was not aware.
Already at that time there were people, who did not carry out the experiments themself, claiming that the experiments gave the proof of thermal energy flowing from colder surface to a warmer.
Pictet, himself, did not agree and kept with his own explanation: the warmer thermometer was sending heat , via a system of mirrors, to the colder ice.
Pictet said already what Johson says.
JeffId, when he opens his freezer is not receiving cold, but his skin initially at 37 C is sending heat to the freezer, and as a result the skin gets cooler and the nerves say to the brain that the freezer is cold.
The small and light thermometer had a small heat capacity as compared to the heavy bed of ice.
Pictet was smart, because in that way the small thermometer, losing heat, showed soon a lower temperature, and the big block of ice received the small amount of heat from the small (air) thermometer and because of its bigger heat capacity the (ice) thermometer did not show a warming up, also because of the latent heat of course.
Carrick
We are truely honoured to have Carrick post here.
Carrick has no need of Feynman, Zemansky or Clausius for that matter he has “moved on”
I gather that Carrick would ban the word HEAT.
Instead we should substitute HEAT ENERGY and perhaps he hopes the rest of the world will “catch on”
He sets out the case here
“I don’t believe “heat” as a physical concept has any place used in this context in modern science, it serves no positive role and simply leads to confusion because almost no two people use the same exact language to describe it.
There is such a thing as “heat energy”, it has units of Joules, and it is proportional to the mean kinetic energy of the ensemble, and it is directly mesurable..”
……………………………………………………………………………………….
So lets see if Carricks new personal definitions explain the problem we have spent a long time discussing on this thread;
The spontaneous radiative transfer of heat between a high temperature surface and one at a lower temperature.
Carricks version
There is an interchange of heat energy between the surfaces but the NET heat energy goes from high to low temperature object
This is what Carrick means by heat energy ……”mean kinetic energy of the ensemble”
But radiation has no mass hence no radiative heat energy transfer is possible by Carricksdefinition!
So Carrick cannot explain radiative transfer even with hisown chosen definition
Look at the economical way Zemansky deals with radiative transfer.
….the difference between the thermal radiation which is absorbed and that which is radiated is called heat.
Thus radiative transfer like conductive and convective transfer will have heat transfer only from a higher temperature to a lower temperature object.
(Zemansky comments on radiation, page 105 of Textbook Heat and Thermodynamics.)
……………………………………………………………….
I think I will stick with Zemansky Feynman and Clausius
.
Carrick had some obscure reference to the cost of textbooks which escapes me.
I expect gratitude from Carrick for setting him straight on some fundamentals definitions of thermodynamics.
Once he has mastered these fundamentals we can move on to more “advanced” work.
But I think it should be clear to all that he is not ready yet.
Heat is apparently too ambiguous a statement. Perhaps energy should be the basis of all thermal discussion. Energy can travel from cold to hot, but the weird concept of work messes everyone’s head up.
“Thus radiative transfer like conductive and convective transfer will have heat transfer only from a higher temperature to a lower temperature object.”
TX:
“Thus net radiative energy transfer like net conductive and net convective energy transfer will have net energy transfer only from a higher energy potential to a lower energy potential object as long as the objects in question are not of a quantum scale.
Everyone happy?
Bryan:
This is pure silliness on your part. What is even your point, other than you can’t be bothered to read a text newer than 50 years of age? Surely you aren’t suggesting that Clausius was the final word on this. Beyond that, this is just a sad attempt at appeal to authority on your part.
I wouldn’t use the word because it is ambiguous and subject to abuse. You can do as you like.
That’s not even my suggestion. It’s more than 40 years old, suggested by people you mistook for educators.
Feel free to replace the phrase with thermal energy if you prefer. But it’s what anybody with a modicum of knowledge in thermodynamics means by the phrase. At least since Boltzmann that is. The modern macroscopic concepts of thermodynamics, whether you like it or not, owe their current meaning and interpretation to the statistical mechanical view. There is a lot of baroque word usage that has been inherited from the
But radiation has no mass hence no radiative heat energy transfer is possible by Carricks definition!
Huh? I’ve talked above about the exchange of thermal photons. You do know that’s how radiative heat energy transfer occurs, don’t you? E= h ν, there is an energy exchange when one molecule or atom emits a photon and another absorbs it.
I really hope that isn’t news to you.
Again, this is just wrong.
LOL. I did, you pitched a hissy fit when you couldn’t follow the maths.
Jeff ID:
Or even better “power”, since generally that’s what we’re talking about, rather than total energy exchange.
If you read the paper in entropy that I linked above, it’s interesting how often people mean “entropy” when they say “heat”.
Didn’t finish a sentence. Here is is completed ” There is a lot of baroque word usage that has been inherited from the [older caloric theory of heat and that has continued to lead to confusion when people try and discuss thermodynamic concepts.]”
Cheers. Dinner time.
Yup energy/time or power.
“Thus net radiative power like net conductive and net convective power will have net transferred power exclusively from a higher energy potential to a lower energy potential object as long as the objects in question are not of a quantum scale.
I’m just glad I took Carrick’s advice and got some popcorn and a cola. I knew it would be fun.
The only time I have seen a real discussion on RC was about……..Heat.
JWR says
Brian ” I would like to thank for the post concerning the experiments of Pictet, some 200 years ago, of which I was not aware.”
Yes its interesting how little some modern geniuses trip themselves up over the basics.
Pictet had to analyse the “radiation of cold phenomena” and Pierre Prévost with his theory of exchanges came up with a dynamical two way radiative explanation .
Today we have the crude distortion proposed by IPCC advocates of a 33K heating effect supposedly because of the radiative properties of certain gases.
I think however you should separate the ideas of Claes Johnston and Joseph Postma.
Claes Johnson wants to revisit the concept of the photon.
Planck and Einstein were literally forced reluctantly to propose the photon as a solution to issues like the photoelectric effect and the so called ultraviolet catastrophe.
In doing so physics lost the concept of causality.
I would be delighted if Claes succeeds but I regard his theories as very much a work in progress.
Now the classical physics explanations culminating with Maxwell and Rayleigh were very successful and indeed for radiation of longer wavelengths the Stephan Boltzmann Equation and Rayleigh’s formulas coincide.
A single Poynting vector gives the magnitude and direction of heat flow.
Currently for areas where the formulas match the preferred operational theory is that of Maxwell.
The photon theory and Maxwell’s approach are only ways that humans try to interpret the underlying reality and all such theories will in time give way to a fuller explanation.
For the moment I and I would imagine Postma will stick with the modern quantum mechanical explanation including dynamic radiative exchange.
Claes is contemptuous of the IPCC AGW agenda.
He has a very prestigious position in one of the worlds top universities
He has come under a lot of “flak” from the greenhouse theory enthusiasts and I would imagine certain zealots of that tendency try to make life difficult for him in his job.
The Halpern (gang of six) that I mentioned earlier would have liked to see the peer reviewed G&T paper banned.
As well as interference in the media and peer group review personal attacks are encouraged
The intolerance of the IPCC zealots is immense and growing as their scam is exposed.
Had Claes avoided a direct confrontation with IPCC dogma then his life and work would have been much easier.
Its not easy being a AGW sceptic
JWR
You might be interested in this article.
http://physicsworld.com/cws/article/news/46193
Thank you, I have recently been searching for information about this topic for a while and yours is the best I’ve discovered till now. However, what about the conclusion? Are you sure about the source?|What i do not realize is actually how you’re no longer actually much more well-favored than you might be right now. You’re very intelligent.