Arguments
The runaway greenhouse effect on Venus
What the science says...
Venus very likely underwent a runaway or ‘moist’ greenhouse phase earlier in its history, and today is kept hot by a dense CO2 atmosphere.
Climate Myth...
Venus doesn't have a runaway greenhouse effect
Venus is not hot because of a runaway greenhouse.
In keeping with my recent theme of discussing planetary climate, I am revisiting a claim last year made by Steven Goddard at WUWT (here and here, and echoed by him again recently) that “the [runaway greenhouse] theory is beyond absurd,” and that it is pressure, not the greenhouse effect that keeps Venus hot. My focus in this post is not on his alternative theory (discussed here), but to discuss Venus and the runaway greenhouse in general, as a matter of interest and as an educational opportunity. In keeping my skepticism fair, I’d also like to address claims (sometimes thrown out by Jim Hansen in passing by) that burning all the coal, tars, and oil could conceivably initiate a runaway on Earth.
It is worth noting that the term runaway greenhouse refers to a specific process when discussed by planetary scientists, and simply having a very hot, high-CO2 atmosphere is not it. It is best thought of as a process that may have happened in Venus’ past (or a large number of exo-planets being discovered close enough to their host star) rather than a circumstance it is currently in.
A Tutorial of Present-Day Venus
Venus’ orbit is approximately 70% closer to the sun, which means it receives about 1/0.72 ~ 2 times more solar insolation at the top of the atmosphere than Earth. Venus also has a very high albedo which ends up over-compensating for the distance to the sun, so the absorbed solar energy by Venus is less than that for Earth. The high albedo can be attributed to a host of gaseous sulfur species, along with what water there is, which provide fodder for several globally encircling sulfuric acid (H2SO4) cloud decks. SO2 and H2O are the gaseous precursor of the clouds particles; the lower clouds are formed by condensation of H2SO4 vapor, with SO2 created by photochemistry in the upper clouds. Venus’ atmosphere also has a pressure of ~92 bars, nearly equivalent to what you’d feel swimming under a kilometer of ocean. The dense atmosphere could keep the albedo well above Earth’s even without clouds due to the high Rayleigh scattering (the effect of clouds on Venus and how they could change in time is discussed in Bullock and Grinspoon, 2001). Less than 10% of the incident solar radiation reaches the surface.
Observations of the vapor content in the Venusian atmosphere show an extremely high heavy to light isotopic ratio (D/H) and is best interpreted as a preferential light hydrogen escape to space, while deuterium escapes less rapidly. A lower limit of at least 100 times its current water content in the past can be inferred (e.g. Selsis et al. 2007 and references therein).
The greenhouse effect on Venus is primarily caused by CO2, although water vapor and SO2 are extremely important as well. This makes Venus very opaque throughout the spectrum (figure 1a), and since most of the radiation that makes its way out to space comes from only the very topmost parts of the atmosphere, it can look as cold as Mars from IR imagery. In reality, Venus is even hotter than the dayside of Mercury, at an uncomfortable 735 K (or ~860 F). Like Earth, Venusian clouds also generate a greenhouse effect, although they are not as good infrared absorbers/emitters as water clouds. However, the concentrated sulfuric acid droplets can scatter infrared back to the surface, generating an alternative form of the greenhouse effect that way. In the dense Venusian CO2 atmosphere, pressure broadening from collisions and the presence of a large number of absorption features unimportant on modern Earth can come into play (figure 1b), which means quick and dirty attempts by Goddard to extrapolate the logarithmic dependence between CO2 and radiative forcing make little sense. The typical Myhre et al (1998) equation which suggests every doubling of CO2 reduces the outgoing flux at the tropopause by ~4 W/m2, although even for CO2 concentration typical of post-snowball Earth states this can be substantially enhanced. Figure 1b also shows that CO2 is not saturated, as some skeptics have claimed.
Figure 1: a) Radiant spectra for the terrestrial planets. Courtesy of David Grisp (Jet Propulsion Laboratory/CIT), from lecture "Understanding the Remote-Sensing Signatures of Life in Disk-averaged Planetary Spectra: 2" b) Absorption properties for CO2. The horizontal lines represent the absorption coefficient above which the atmosphere is strongly absorbing. The green (orange) rectangle shows that portion of the spectrum where the atmosphere is optically thick for 300 (1200) ppm. From Pierrehumbert (2011)
How to get a Runaway?
To get a true runaway greenhouse, you need a conspiracy of solar radiation and the availability of some greenhouse gas in equilibrium with a surface reservoir (whose concentration increases with temperature by the Clausius-Clapeyron relation). For Earth, or Venus in a runaway greenhouse phase, the condensable substance of interest is water— although one can generalize to other atmospheric agents as well.
The familiar water vapor feedback can be illustrated in Figure 2, whereby an increase in surface temperature increases the water vapor content, which in turn results in increased atmospheric opacity and greenhouse effect. In a plot of outgoing radiation vs. temperature, this would result in less sensitive change in outgoing flux for a given temperature change (i.e., the outgoing radiation is more linear than one would expect from the σT4 blackbody-relation).
Figure 2: Graph of the OLR vs. T for different values of the CO2 content and relative humidity. For a fixed RH, the specific humidity increases with temperature. The horizontal lines are the absorbed shortwave radiation, which can be increased from 260-300 W m-2. The water vapor feedback manifests itself as the temperature difference between b’-b and a’-a, since water vapor feedback linearizes the OLR curve. Eventually the OLR asymptotes at the Komabayashi-Ingersoll limit. Adopted from Pierrehumbert (2002)
One can imagine an extreme case in which the water vapor feedback becomes sufficiently effective, so that eventually the outgoing radiation is decoupled from surface temperature, and asymptotes into a horizontal line (sometimes called the “Komabayashi-Ingersoll” limit following the work of the authors in the 1960’s, although Nakajima et al (1992) expanded upon this limiting OLR in terms of tropospheric and stratospheric limitations). In order to sustain the runaway, one requires a sufficient supply of absorbed solar radiation, as this prevents the system from reaching radiative equilibrium. Once the absorbed radiation exceeds the limiting outgoing radiation, then a runaway greenhouse ensues and the radiation to space does not increase until the oceans are depleted, or perhaps the planet begins to get hot enough to radiate in near visible wavelengths.
Figure 3: Qualitative schematic of how the ocean reservoir is depleted in a runaway. From Ch. 4 of R.T. Pierrehumbert’s Principles of Planetary Climate
On present-day Earth, a “cold trap” limits significant amounts of water vapor from reaching the high atmosphere, so its fate is ultimately to condense and precipitate out. In a runaway scenario, this “cold trap” is broken and the atmosphere is moist even into the stratosphere. This allows energetic UV radiation to break up H2O and allow for significant hydrogen loss to space, which explains the loss of water over time on Venus. An intermediate case is the “moist greenhouse” (Kasting 1988) in which liquid water can remain on the surface, but the stratosphere is still wet so one can lose large quantities of water that way (note Venus may never actually encountered a true runaway, there is still debate over this). Kasting (1988) explored the nature of the runaway /moist greenhouse, and later in 1993 applied this to understanding habitable zones around main-sequence stars. He found that a planet with a vapor atmosphere can lose no more than ~310 W/m2, which corresponds to 140% of the modern solar constant (note the albedo of a dense H2O atmosphere is higher than the modern), or about 110% of the modern value for the moist greenhouse.
Earth and the Runaway: Past and Future
Because Earth is well under the absorbed solar radiation threshold for a runaway, water is in a regime where it condenses rather than accumulating indefinitely in the atmosphere. The opposite is true for CO2, which builds up indefinitely unless checked by silicate weathering or ocean/biosphere removal processes. In fact, a generalization to the runaway threshold thinking is when the solar radiation is so low, so that CO2 condenses out rather than building up in the atmosphere, as would be the case for very cold Mars-like planets. Note the traditional runaway greenhouse threshold is largely independent of CO2 (figure 2 & 4; also see Kasting 1988), since the IR opacity is swamped by the water vapor effect. This makes it very difficult to justify concerns over an anthropogenic-induced runaway.
Figure 4: The H2O–CO2 greenhouse. The plot shows the surface temperature as a function of radiated heat for different amounts of atmospheric CO2 (after Abe 1993). The albedo is the fraction of sunlight that is not absorbed (the appropriate albedo to use is the Bond albedo, which refers to all sunlight visible and invisible). Modern Earth has an albedo of 30%. Net insolations for Earth and Venus ca. 4.5 Ga (after the Sun reached the main sequence) are shown at 30% and 40% albedo. Earth entered the runaway greenhouse state only ephemerally after big impacts that generated big pulses of geothermal heat. For example, after the Moon-forming impact the atmosphere would have been in a runaway greenhouse state for ∼2 million years, during which the heat flow would have made up the difference between net insolation and the runaway greenhouse limit. A plausible trajectory takes Earth from ∼100 bars of CO2 and 40% albedo down to 0.1–1 bar and 30% albedo, at which point the oceans ice over and albedo jumps. Note that CO2 does not by itself cause a runaway. Also note that Venus would enter the runaway state when its albedo dropped below 35%. Se e Zahnle et al 2007
This immunity to a runaway will not be the case in the long-term. In about a billion years, the sun will brighten enough to push us into a state where hydrogen is lost much more rapidly, and a true runaway greenhouse occurs in several billion years from now, with the large caveat that clouds could increase the albedo and delay this process.
Interesting, some (e.g.. Zahnle et al 2007) have argued that Earth may have been in a transient runaway greenhouse phase within the first few million years, with geothermal heat and the heat flow from the moon-forming impact making up for the difference between the net solar insolation and the runaway greenhouse threshold, although this would last for only a brief period of time. Because the runaway threshold also represents a maximum heat loss term, it means the planet would take many millions of years to cool off following such magma ocean & steam atmosphere events of the early Hadean, much slower than a no-atmosphere case (figure 5).
Figure 5: Radiative cooling rates from a steam atmosphere over a magma ocean. The radiated heat is equal to the sum of absorbed sunlight (net insolation) and geothermal heat flow. The plot shows the surface temperature as a function of radiated heat for different amounts of atmospheric H2O (adapted from Abe et al. 2000). The radiated heat is the sum of absorbed sunlight (net insolation) and geothermal heat flow. The different curves are labeled by the amount of H2O in the atmosphere (in bars). The runaway greenhouse threshold is indicated. This is the maximum rate that a steam atmosphere can radiate if condensed water is present. If at least 30 bars of water are present (a tenth of an ocean), the runaway greenhouse threshold applies even over a magma ocean. Note that the radiative cooling rate is always much smaller than the σT4 of a planet without an atmosphere
Conclusions
Venus likely underwent a runaway or “moist greenhouse” phase associated with rapid water loss and very high temperatures. Once water is gone, silicate weathering reactions that draw down CO2 from the atmosphere are insignificant, and CO2 can then build up to very high values. Today, a dense CO2 atmosphere keeps Venus extremely hot.
Last updated on 11 April 2011 by Chris Colose. View Archives
It always amazes me how many people get the Ideal Gas Law wrong with the 'Pressure causes Temperature' idea. But explaining it never helps, they just don't get it.
Lots of posturing, yet no explanation why the poles of Venus are as hot as the equator, why the night side is as hot as the day side, and why Jupiter, which has an atmosphere made of H2 and He which are not greenhouse gases, has a temperature of 260 F at a depth in the atmosphere where the P is 11 bars.
[RH] Need I remind you that you are currently skating on thin ice with regards to your commenting privileges. Posting links to blog posts instead of published research and then calling published research "posturing" does not help you. Stick to the published research, if there is any, to support your position, please.
How many times would we have to double Earth's CO2 to be the same as Venus, which is 96% CO2 and is 93 times denser than Earth's? The answer is 18. Starting at 400 and doubling:
800
1600
3200
6400
12800
25600
51200
100k
200k
400k
800k
1.6m
3.2m
6.4m
12.8m
25m
50m
100m
With a climate sensitivity of 2C per doubling, Earth would only be 2 x 18 or 32 C warmer than it is now, using the greenhouse effect of CO2
[RH] Try using central estimates for CS of 3°C.
Mike Hillis, Skeptical Science is not intended to be an encyclopedia. You need to exert A little independent effort before posting your off topic diatribes.
Also Mike.
The forcing effect of CO2, at so much per doubling, isn't the same ratio all the way up to those very high concentrations. Additional wavelengths come into play at those higher concentrations, a process called Continuum Absorption comes into play, and the Lapse Rate of the atmosphere of Venus is more like 10.4 Deg C per km vs 6.5 here on Earth. Also there is SO2 present on venus that isn't present here on Earth. And since there is cloud covering the entire planet, not just part of it even though SO2 clouds aren'e as effective as emitters as water clouds, this still produces a bigger GH effect from clouds than here on Earth. Since the Bond Albedo of Venus is around 0.9 - 90% reflection, much from those clouds, the GH effect impact of those clouds would also be substantial.
You can't extrapolate simply from the current climate on Earth, you actually need to run the radiation modelling programs with venus's atmosphere to get the correct result.
From the post above "In the dense Venusian CO2 atmosphere, pressure broadening from collisions and the presence of a large number of absorption features unimportant on modern Earth can come into play (figure 1b), which means quick and dirty attempts by Goddard to extrapolate the logarithmic dependence between CO2 and radiative forcing make little sense."
A better way of thinking about it, is to use the radiation calculations to determine what the effective radiating height for the atmosphere is, the average altitude that radiation to space originates from. For the Earth that is around 5 km up, for Venus it is over 50 km up. The average temperature at that altitude will be at around the effective radiating temperature the planet needs to be at to be in energy balance. For the earth that is -18C. For Venus it is more like -80 - -90 C. So a lapse rate of 6.5, over a 5km altitude makes the surface of the Earth around 32.5C warmer than the effective emission level so around 14-15C.
For Venus, a lapse rate of 10.2 approximately and an effective emission height of over 50 km gives a surface temperature something of the order of 510-550 C warmer that the effective emission level, so the surface temperature should be something like 420-470C.
Returning to Mike Hillis @ 121:
1)
Actually, it has been predicted since Svante Arrhenius in 1896 that increasing the greenhouse effect will warm the poles more than the equator, in winter more than in summer, and it has also been shown that the greenhouse effect warms nights more than days. Carried to extremes, these features easilly explain why Venutian nights should be as warm as days, and polar regions as warm as tropical regions in the lower troposphere. In contrast, no presentation of the theory you appeal to purports to show the same thing.
2)
The blog post for which you provide a link appeals to a paper showing temperature hotspots at high altitudes to prove that the adiabatic lapse rate applies throughout the entire atmosphere. That is, it appeals to a paper that falsifies its claim as proof of that claim. It further claims the existence of the adiabatic lapse rate (where it exists) is proof of their preferred theory (of which more in a later post) even though it is a well known feature, and an important feature of the standard greenhouse theory since Manabe and Wetherald (1967), and a well known feature of all atmospheres in regions dominated by convection long before that.
3)
In fact measured solar flux on the Venutian surface is between 35 and 40 W/m^2 at the surface (see figure 6). On the other hand, global mean net solar flux (accounting for differences in latitude, season and the day night cycle) in only about 8 W/m^2. Both of these are substantially smaller than is the case on Earth, due to the thick cloud, but they are more than sufficient to generate an adiabatic lapse rate in the Venutian troposphere (as is proven by its existence). If all solar heating was dissipated in the clouds, as you claim, the surface would be cooler than the clouds, just as the tropopause is cooler than the stratosphere due to the heating of ozone in the stratosphere by UV radiation on Earth. That is, if you were right about this point, the very precondition for validity of your preferred (in not understood) theory would be false.
4)
The only way gravity 'generates' energy, and hence raises temperatures, is the conversion of gravitational potential energy to kinetic energy by masses falling towards the surface. For an atmosphere in equilibrium, there is no net infall of material, and hence no net energy conversion from potential to kinetic forms. The atmospheres of rocky planets, including Earth and Venus are very thin, and have reached quasi-equilibrium a long time ago. Ergo, no net conversion of potential energy to kinetic energy, and no overall warming of the atmosphere by gravitation. End of story. Your explanation is a non-starter, and shows all the accumen demonstrated by various inventors of perpetual motion machines (which it would allow, if valid).
Tom Curtis 131
Quasi equilibrium is not equilibrium. Small motion, even brownian motion, is enough. All small parcels of gas, even single molecules, generate heat on the way in and release it on the way out. Gas moves in, compresses, heats up, releases heat to the neighboring gas at lower elevation, moves back up, cools, absorbs heat from neaghboring gas at higher elevation, moves back down, etc. If you don't understand how vertical movement of gas generates heat and transfers it in a downward direction, then you probably don't understand why Death Valley is so hot, or why the San Gabriel and Santa Ana winds heat up as the elevation decrease, even at night. These are called katabatic winds https://en.wikipedia.org/wiki/Katabatic_wind and happen all over Antarctica. In the extreme, as on Venus and Jupiter, they explain everything. Taken to the extreme extreme, near the core of Jupiter, the temperature is 20,000 K. and the Kelvin Helmholtz theory isn't even necessary (that theory requires permanent compression....not needed).
Please no talk about perpetual motion machines. The solar system has been in motion for only 4.6 by, and that's a long time but not perpetual. Tidal forces and the friction it gererates will eventually stop the rotation of Venus, but until then, the motion, all motion, within its atmosphere, will continue to generate heat katabatically.
Mike Hillis @132, don't be a fool. Downward motion of air heats the air, but upward motion of air cools it. If the same amount moves up as down, there is no net heat generated, and hence no possibility that this mechanism will raise temperatures above what they would have been from solar input alone. As it happens, convective equilibrium is achieved within hours in the troposphere. Given that, the idea that after 4.6 billion years there continues to be a net settling of the atmosphere that is needed to generate excess heat is absurd.
Mike Hillis:
Did you check out KR’s link in @123? Look at figure 3c on page 4 (lower left). The red curve shows measurements by the Soviet Venera 15 probe of outgoing IR radiation from Venus.
Do you have any idea of what that curve would look like if the extreme temperature on Venus was caused by gravitational compression – or any other heat source – rather than IR absorption in the atmosphere?
Hint: You would have to expand the y-axis a lot!
Tom @ 133 as I already said, as the air moves down it adds heat to the air it decends to. As it ascends, it takes heat from the air it ascends to. In BOTH directions, it transfers heat from higher to lower. Read again what I said.
HK @ 134 Venus is much hotter than Earth and radiates at shorter wavelengths, so we can pay more attention to the 2 and 3 4.5 micron bands and less to the 15 mike band. Take another look at the graph.
2 and 3 and 4.5 I meant
And just to be clear on Tom Curtis @ 133:
We are not talking about generating heat. We are talking about transferring heat, in this case, transferring it from every layer of the atmosphere to the surface. The heat comes from the sun, absorbed by the atmosphere so that only 10% of the light that falls on Venus ever reaches the surface. The bulk of the heat is transferred to the surface by the gravity heat pump mechanism I described.
Mike Hillis @135, you also said:
What you should have said is that, "until then, the motion, all motion, within its atmosphere, will continue to generate and remove heat in equal proportions katabatically" unless you take the delussory view that all atmospheric motion on Venus is downward.
What this mechanism does, and the only thing it does, is to generate the lapse rate in the troposphere. That is, it establishes a linear relationship between the temperature difference and distance along the vertical axis within the troposphere. It cannot, by itself, determine the exact value of the temperature at any point in the troposphere.
Mike Hillis, just to be clear here - do you believe that if you put venus atmosphere into an ordinary GCM using only known physics, then the temperature and isothermal structure of surface is not reproduced?
ie it is "unexplained" by known physics?
Mike Hillis @136:
My point is that Venera’s measurements clearly show that the IR radiation escaping from Venus can’t come from near its surface, but from much colder and therefore much less radiating layers in its upper atmosphere.
If the high temperature was caused by any physical process that adds heat rather than slows down the heat loss to space (as the GHE does), the spectrum of the outgoing IR from Venus would look completely different. Using the wavenumber scale (as done in the graph), the peak radiation would be more than 20 times higher (thus the need to enlarge the y-axis!), and shifted to about 1440 cm-1.
BTW, the 15 µm band (667 cm-1) is important for the Venusian greenhouse effect exactly because almost all the heat loss to space happens from the very cold, upper layers of the atmosphere and not from near the surface.
Mike Hillis at @135
"as I already said, as the air moves down it adds heat to the air it decends to. As it ascends, it takes heat from the air it ascends to. In BOTH directions, it transfers heat from higher to lower"
Actually Mike, you have this back-to-front. As air moves down heat is added to it from the surrouning air. And as air rises heat is removed from it by the surrounding air. You are leaving important aspects of the problem out - potential energy changes and work.
A parcel of air that is rising in the atmosphere is being lifted by some force, air pressure, buoyancy, whatever. So work is being done on it. However, because it is rising, the air parcel is also gaining potential energy. When we work out the math, the work done on the parcel exactly matchs the potential energy gain. So conservation of energy says no net change in the energy of the parcel. At the scale of air movements in the atmosphere there is little mixing between parcels, so no scope for significant heat transfer between them And in a dense atmosphere radiative transfer is very poor. So the movement of the air parcel is essentially adiabatic - no net heat flow in or out.
So the parcel would rise to a higher altitude essentially unchanged same volume, same pressure, same temperature. However, pressure can't stay the same. At higher altitude air pressure is lower, and air pressure must equalise. So the parcel has to expand to equalise pressure with the surrounding air. But in order to expand the parcel has to push the other parcels around it aside to make room for its expansion. It has to do work on them. So there is an energy transfer from the rising parcel to the surrounding air as work. But conservation of energy says this energy has to come from somewhere. And the only energy source available is the internal energy of the rising air parcel. In order to supply the energy needed to push other air parcels aside, the rising parcel loses internal energy. Its temperature drops as it transfers energy to its surroundings.
For descending air parcel it is the reverse. as it descends, pressure equalisation means that the surrounding air compresses the parcel, doing work on it, adding to its total energy which since the situation is adiabatic can only manifest as an increase in the temperature of the parcel.
Rising air heats its surroundings and is thus cooled by them, falling air is heated by its surroundings and cools them.
Adiabatic changes in temperature don't add or lose total heat, because when the volume goes down the T goes up so total heat in parcel remains the same. Just the temperature changes. The amount of heat in the parcel of air remains the same, all that changes in the temperature and volume according to
So if PV goes up, T goes up, but when the temperature goes up the total heat contained stays the same because the volume goes down. That's how it works. Heat stays the same and volume goes down, the temperature goes up. Follow with me closely:
1. Parcel moves down and compresses
2. Heat stays the same but T goes up
3. Parcel equilibiates T with lower elevation surrounding air by adding heat to it
4. Parcel moves up and expands
5. Heat in parcel stays the same but T goes down
6. Surrounding air adds heat to parcel to equilibriate T
All heat added to parcel from surrounding air is at higher elevation, all heat lost from parcel is at lower, so heat is moved from high elevation towards low until it reaches the surface.
This is for ALL vertical motion of air, whether is be large air masses, small parcels, or brownian motion, and at any and all elevations.
And since horizontal motion of air is many times faster than vertical, the air parcels are quickly moving around the planet, which is why the poles on Venus are the same temperature as the equator, and the night side is at warm as the daylit side.
Glenn @ 142 says
No, the source of energy is the Sun
[RH] Please avoid using all caps, per comments policy.
Mike Hills,
Your arguments started out interesting but have gone way down. I suggest you review basic chemistry and physics before you post again. You need to stop reading from the blog source you are getting your information from. Keep in mind that Steve Goddard thinks CO2 can fall as snow at the south pole and be sequestered there forever. If you want to convince readers here you have to get the High School Chemistry (which I teach) correct.
Heat and temperature are directly proportional in a given parcel of air. If the temperature increases as the parcel as it sinks, the heat increases. The heat has to come from somewhere. It cannot come from the parcel itself as that would violate the first law of thermodynamics. Glenn's explaination that the energy comes from the work the surroundings does (or that a rising parcel does on the surroundings) is the correct one. Read his post again if you are unclear about where the heat comes from.
Venus is the classic example of a runaway greenhouse effect. Arguing that Venus is not a greenhouse planet will not get you any converts at a scientific site.
Can you find a scientific reference (paper or textbook) that caims Venus is not a greenhouse (I note that you have not referred to any scientific papers in your arguments, only blog science)? If you cannot perhaps you should consider that it is because Venus really is a greenhouse and your blog science is incorrect.
Your claim that heat can be transferred from the cold upper atmosphere to the warmer lower atmosphere is also a violation of the laws of thermodynamics.
I will try not to comment again since dogpiling is against the comments policy.
Mike Hillis @143:
"Adiabatic changes in temperature don't add or lose total heat...."
Are you saying that adiabatic processes can’t change the total heat content in the atmosphere of Venus (or any other planet) and that the high temperature near the surface is only caused by a redistribution of heat?
(A short yes or no is sufficient)
@144
Yes, as long as you don't change the pressure or volume, which can change the T without changing heat content. High school chemistry teachers should know this.
pV = nRT says if you increase PV, the T goes up even though you have not added heat. The work done to change the parcel's elevation and raise or lower the PV is uneven solar heating of the atmosphere.
I will not state my argument again because repeating oneself is against comments policy.
@ 145
Yup. Only the sun can change the total heat content of the atmosphere.
Michael sweet @144
That is an error. This is what Steve Goddard actually says:
https://stevengoddard.wordpress.com/2012/06/12/antarctic-temperature-drops-below-the-freezing-point-of-co2/#comments
Mike Hills,
Any chemistry text will say that Boyles law is PV=Constant (Wikipedia) or page 297 Corwin Introductory Chemistry (textbook for the local Community College). Your claim that PV can somehow increase on their own without the addition of energy from an outside source is simply false. You must provide a scientific reference (blog science is not good enough) to support your absurd claim that PV can increase on their own. Since PV = constant, the only way to change the temperature is to add energy. Read Glen's comment for the correct explaination of how the work done by the atmosphere changes the heat content of the parcel. (Heat and work are both forms of energy so work done = heat increase).
The thread at WUWT where Goddard claimed that CO2 would fall as snow at the south pole was deleted after even Watts realized that it made him look stupid to have such junk on his site. Goddard was then banned from WUWT for being so unscientific. (Imagine what it takes to get banned from WUWT for being unscientific!!)
It is clear that this thread is a waste of time and others have been doing a good job countering your blog "science". I will no longer comment.
@ 149
From your link to Wikipedia:
The equation states that product of pressure and volume is a constant for a given mass of confined gas as long as the temperature is constant.
So, as long as T is constant and the gas is confined (V is constant), then, yeah.
For the rest of us, PV = nRT
[RH] Corrected comment @151.