By Steve Goddard
The classic cure for hyperventilation is to put a paper bag over your head, which increases your CO2 levels and reduces the amount of Oxygen in your bloodstream. Global warmers have been hyperventilating over CO2 on Venus, ever since Carl Sagan made popular the idea of a runaway greenhouse effect. That was when he wasn’t warning about nuclear winter.
Sagan said that marijuana helped him write some of his books.
I bought off on the “runaway greenhouse” idea on Venus for several decades (without smoking pot) and only very recently have come to understand that the theory is beyond absurd. I explain below.
The first problem is that the surface of Venus receives no direct sunshine. The Venusian atmosphere is full of dense, high clouds “30–40 km thick with bases at 30–35 km altitude.” The way a greenhouse effect works is by shortwave radiation warming the ground, and greenhouse gases impeding the return of long wave radiation to space. Since there is very little sunshine reaching below 30km on Venus, it does not warm the surface much. This is further evidenced by the fact that there is almost no difference in temperature on Venus between day and night. It is just as hot during their very long (1400 hours) nights, so the 485C temperatures can not be due to solar heating and a resultant greenhouse effect. The days on Venus are dim and the nights are pitch black.
The next problem is that the albedo of Venus is very high, due to the 100% cloud cover. At least 65% of the sunshine received by Venus is immediately reflected back into space. Even the upper atmosphere doesn’t receive a lot of sunshine. The top of Venus’ atmosphere receives 1.9 times as much solar radiation as earth, but the albedo is more than double earth’s – so the net effect is that Venus’ upper atmosphere receives a lower TSI than earth.
The third problem is that Venus has almost no water vapor in the atmosphere. The concentration of water vapor is about one thousand times greater on earth.
Composition of Venus Atmosphere
0.965 CO2
0.035 N2
0.00015 SO2
0.00007 AR
0.00002 H2O
Water vapor is a much more important greenhouse gas than CO2, because it absorbs a wider spectrum of infrared light – as can be seen in the image below.
http://www.globalwarmingart.com/images/7/7c/Atmospheric_Transmission.png
The effects of increasing CO2 decay logarithmically. Each doubling of CO2 increases temperatures by 2-3C. So if earth went from .04% CO2 to 100% CO2, it would raise temperatures by less than 25-36C.
Even worse, if earth’s atmosphere had almost no water (like Venus) temperatures would be much colder – like the Arctic. The excess CO2 does not begin to compensate for the lack of H2O. Water vapour accounts for 70-95% of the greenhouse effect on earth. The whole basis of the CAGW argument is that H2O feedback will overwhelm the system, yet Venus has essentially no H2O to feed back. CAGW proponents are talking out of both sides of their mouth.
So why is Venus hot? Because it has an extremely high atmospheric pressure. The atmospheric pressure on Venus is 92X greater than earth. Temperatures in Earth’s atmosphere warm over 80C going from 20 kPa (altitude 15km) to 100 kPa (sea level.) That is why mountains are much colder than the deserts which lie at their base.
The atmospheric pressure on Venus is greater than 9,000 kPa. At those pressures, we would expect Venus to be very hot. Much, much hotter than Death Valley.
http://en.wikipedia.org/wiki/File:Emagram.GIF
Wikipedia typifies the illogical “runaway greenhouse” argument with this statement.
Without the greenhouse effect caused by the carbon dioxide in the atmosphere, the temperature at the surface of Venus would be quite similar to that on Earth.
No it wouldn’t. 9000 kPa atmospheric pressure would occur on earth at an altitude many miles below sea level. No such place exists, but if it did – it would be extremely hot, like Venus. A back of the envelope estimate – temperatures on earth increase by about 80C going from 20 to 100 kPa, so at 9,000 kPa we would expect temperatures to be in the ballpark of :
20C + ln(9000/(100-20)) *80C = 400C
This is very close to what we see on Venus. The high temperatures there can be almost completely explained by atmospheric pressure – not composition. If 90% of the CO2 in Venus atmosphere was replaced by Nitrogen, it would change temperatures there by only a few tens of degrees.
How did such bad science become “common knowledge?” The greenhouse effect can not be the cause of the high temperatures on Venus. “Group Think” at it’s worst, and I am embarrassed to admit that I blindly accepted it for decades.
Blame CO2 first – ask questions later.
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UPDATE: Lubos Motl has written an essay and analysis that broadly agrees with this post. See it here
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Earth’s atmosphere has 1,000 times the concentration of water as Venus. Venus has only 90 times as much atmosphere. That means that earth has 10 times as much water stored in the atmosphere as Venus, plus a massive buffer of excess water in the oceans.
Kenneth Chang of the NY Times and I had an email exchange last year and this very subject was thrown out there. This is lifted word for word from one of his responses to me:
“Let’s turn the question around: what would convince you that the climate is warming? I’m guessing that actual temperature data from other parts of the world (and images of shrinking glaciers and stuff like that) are not convincing data to you, either. The policy questions don’t hinge much on Antarctica. I guess I also don’t understand how you could be so certain that CO2 emissions could a priori never cause warming. The fundamental basic physics of carbon dioxide says it should. And for clear proof that CO2 in sufficient quantities can cause global warming, there’s Venus.”
This guy is the “science” reporter for the Times….
“It’s theorized that Titan has liquid water under it’s miles of ice due to heating from the tidal effects of Jupiter…”
I doubt there are any such theories. Titan orbits Saturn.
Interestingly, Titan has a surface atmospheric pressure 60% greater than Earth’s and the temperature is minus 178C. Other Saturnian moons with no atmosphere at all have average temperatures only about ten degrees colder. Without a heat source (internal or external), atmospheric pressure contributes little in and of itself.
SO2 produced on the surface reacts with water vapor to form sulfuric acid (droplets) stabilized to boiling by the catalyst (dust) in the Venusian atmosphere, and that reaction produced quite a bit of heat?
Note that the martian atmosphere of 95-99% CO2 (at 3-5 mm Hg pressure) does not contribute to the heat of Mars at all. The size of the planet and the heat capacity of Martian soil account completely for the diurnal change in temp of up to 250K.
Carl Sagan had way to many conversations with extraterrestrials. I think they were responsible for a lot of his bad judgment
I guess the high pressure at the bottom of the Ocean explains why it is so hot down there…
Re: Dave McK says @ur momisugly May 6, 2010 at 3:23 pm
You get it. Good on you!
Hi Steven
If the atmosphere were to behave as an ideal gas the pressure cannot determine the long-term temperature. The atmospheric pressure at the planet surface would be determined by the total weight of the atmosphere divided by the total area of the planet. If the atmosphere is losing more heat by radiation than it receives from all sources (the sun plus any flow from a hot interior) then the atmosphere will cool. As it cools it will contract so that its volume decreases. The high pressure does not determine the temperature. Temperature decreases with altitude in the troposphere of a planetary atmosphere because heat is being radiated more from a higher level so a negative temperature gradient is established. I rather fear that your article will give the CAGW alarmists an avenue to attack us.
Kind regards, DougB
Alright guys, this redhead is hyperventilating cuz we are just about to start the fishing season and I don’t have the rod I want! I just bought (well, last month) a very nice baitcasting reel and am looking for a shorter, flexible baitcasting rod so that I can fish along a brushy tree lined river. I am not fond of spinners as they snap the line back when I want to stop the line at the other side of the bank (which is where the trout I want ALWAYS are, right?). I want a flexible rod that takes 4 to 8 lb test that is less than 7 feet and preferably 6’6″. Got any ideas where I can find such a rod without going to #%*$ Venus????
Just for general interest, here is a graphic description of the total amount of water in the oceans and air in the atmosphere compared with the planet. [Water on left, air on right.]
20 minutes till sunset in Chicago, then Venus will be very bright in the West/Northwest. Conditions on Venus are being extrapolated? with our conditions?
We live here, and can’t figure it out.
3.4 billion years of asteroids, volcanos, continental drift and ice ages.
The results (not obliterated), are still being discovered/studied.
The next 1000 years, will be a “blink of an eye” in Earth’s geologic history.
P.S. Don’t tell Al Gore. Lest his head explode.
I know, you know, but had to say it.
Here is the part that still confuses me. Looking at the Radiation Transmitted by the Atmosphere chart. At the Wavelenghs that CO2 absorbs radiation, no radiation escapes the earth. How does adding more CO2 decrease the outgoing radiation more that it does.
It is like an assembly like with multicolored M&M going down it. If one person is removing red M&Ms. Lots of red M&Ms get through. With each added person, fewer get through. At some point, the odds of a red M&M getting through is very small.
Is there any measured data that says some of the radiation in CO2 absorbing wavelengths are actually getting through? If not, how can increasing CO2 levels capture more outgoing radiation?
Pamela Gray
It sounds like they would be ideal candidates for the nickel or copper head spinners… You use a short high velocity spinner launching “rod”(also known as a rifle in some countries) and place the spinner just above offending fish… then you just require a net to scoop them out, or wait down stream at an eddie that catches em… hope this cures yah hyperventilating. (also is ideal to use for spot light aided night fishing)
Nick Stokes says:
May 6, 2010 at 5:23 pm
Nick, I’d be interested in your comments on the Volz piece I referenced above.
Both explanations, “it’s the CO2” and “it’s the pressure”, are too glib in themselves. As pointed out in a previous post, high temperatures result in a thick atmosphere.
The present Venusian climate is stable, despite the combination of high albedo and high temperature. The interesting question is how did it get this way?
According to explanations I’ve seen, it is believed that Venus used to have a lot of water; that at some point the Sun’s heat baked a lot of CO2 out of the rocks; that the combination of CO2 and water vapour drove up the temperatures; and that although subsequent dissociation of the water lost its hydrogen into space, the thick atmosphere is enough to sustain the present balance.
If that is correct, it stills represent a feasible scenario for Earth’s future – indeed, rather likely when the sun eventually gets hot enough or large enough.
One way to challenge that explanation would be to show our models do not match its present energy balance. Do they? I don’t know, but that does not appear to be a claim being made in this blog.
PJF, this link shows the temp/pressure profile of the Venusian atmosphere. Note that around 1 Earth atmosphere of pressure, the atmospheric pressure is roughly the same as the Earth’s.
http://www.datasync.com/~rsf1/vel/1918vpt.htm
Zeke says:
May 6, 2010 at 12:36 pm
Also, Carl Sagan smoking pot is a bit of a cheap shot :P>>
Surely you jest.
It was clearly a pot shot.
Bill Illis @5:22
“Generally, I think pressure and, in effect, the work being done by gravity, has not been taken into account in global warming theory and someone needs to put it back in.”
Right on. I am so sick of seeing all these discussions that focus on only one variable, like radiation.
Those folks who keep saying that AGW is “proven” with basic physics need to explain some anomalies, and it is my experience that they are reluctant to do that. For example, please provide a K&T-style “radiation equilibrium diagram” for Fiji! I guess Neoscience allows folks to totally ignore empirical evidence.
Steven G, May 6, 2010 at 5:44 pm
I don’t believe I did misquote you, but anyway the issue is there. High temps create a huge IR flux, and something has to block that, otherwise losses will far exceed the energy supply. The adiabatic effect can’t create a large heat flux.
Stephen Goldstein says:
May 6, 2010 at 1:18 pm
“…Say I connect a SUBA diver’s air tank to a compressor and “fill” the tank with compressed air. I ask how come the tank is warm and you reply “because it has an extremely high pressure.” Okay, but I come back in an hour, the gauge still reads 3000psi but the tank is no longer warm. How come? The gas is still at an extremely high pressure…”
Because the cylinder won’t be at 3000psi when you come back. The ideal gas law still applies: PV=nRT. You haven’t changed V (entire cylinder). You haven’t changed n (amount of stuff, i.e. moles). You haven’t changed R (material properties of the stuff). You have changed T (lower) and so you have changed P. Having filled SCUBA tanks at my dad’s shop lo’ the many years ago I can attest to this. Tanks were filled in a bath of water to draw the heat of compression off as quickly as possible and were only considered full when they measured 3000psi (or 2400 depending on whether they were aluminum or steel) and were only moderately warm to the touch. If we hadn’t done that we would have had some pissed off customers who didn’t get the full amount of air they’d paid for.
Having said that I’m in the camp that the application of the ideal gas law doesn’t explain Venus. Take away the sun or perhaps its own vulcanism and Venus would have to cool through radiation to the local background, i.e. ~4K, and the pressure of its atmosphere would not maintain its temperature indefinitely, nor would the pressure or volume remain constant.
PJF, I think about the P-T -H profiles of atmosphers a lot.
Let’s start at the basic. Without external energy inputs, all planetary atmospheres will ultimately form a crust on the surface of the planet and have zero height.
With external energy input, that crust will evaporate and form an atmosphere. The P-T-H characteristics of that atmosphere are defined primarily, I believe, by three things:
1. The ratio of the mass of the atmosphere to the mass of the planet
2. The radiative energy budget, which must equalise at the “top” of the atmosphere.
3. The thermodynamic requirement for all parts of the atmosphere to have the same total energy – thus we must consider the sum of gravitational and thermal energy.
No, no, no!!! I’m not talking about a lure spinner. I am taking about the rod. A baitcasting rod has a trigger on it (a place for parts of your hand so you can use other parts to slow down the line as you land that fat worm just where you want it). A spinning rod doesn’t have this thorn like feature under the rod. But most baitcasting rods are made for bass fishing (a fat heavy fish) and are usually made for 8+ pound test weight (think log size girthy rod, not twig size skinny rod). I want an ultralight baitcasting rod (twig size skinny and flexible) with the trigger and I want it to be short (less than 7 ft), not the usual length for such a rod. I want to use 4 to 8 lb test. Any baitcasting rod I have found is too long and too telephone pole stiff for trout.
See???? I am hyperventilating again!!!!! Come on you guys!! You’re GUYS! You should know this stuff!!!!
Thanks, Willis, for that interesting link. John Daly had a post up the thread showing why the Earth and Venus can’t be compared:
And PJF responds @5:56 pm to this comment:
“It’s theorized that Titan has liquid water under it’s miles of ice due to heating from the tidal effects of Jupiter…”
with:
“”I doubt there are any such theories. Titan orbits Saturn.””
Actually, Titan has immense quantities of hydrocarbons.
[source]
Nick:
““No such place exists, but if it did – it would be extremely hot, like Venus.”
No, it wouldn’t, not without a greenhouse effect. A surface at 700K emits about 12,000 W/m2. Incoming sunlight, averaged over surface area, on Venus is about 400 W/m2. If the atmosphere is transparent to thermal IR, that 12,000 W/m2 would just go out to space and sunlight couldn’t possibly balance it. The surface would cool. …”
Nick, I’m still waiting for an “equilibrium radiation balance diagram” for Fiji (K&T play around with an “average,” which means absolutely nothing when radiation varies as T^4–it means nothing for a real “spot” on Earth).
Now, in that comfortable clime of Fiji, there is adequate radiation JUST from the water to “explain” the air temperature year-around. The damn Sun just keeps heating the water up each day. The “backradiation” is not needed, and, indeed, if it were employed in the diagram, it would make the temperatures so high that the Fiji People would be fried. The GHG effect is an apparition, methinks. Can you explain this anomaly?
I await your diagram.
Sorry, I meant Europa. Brain freeze. 🙂
Smokey
There is essentially no difference in surface temperature between the day and night sides of Venus.