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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Hurray! I’ve been saying this for years, and every time I say it, everybody ignores me.
http://noconsensus.wordpress.com/2010/04/19/radiative-physics-yes-co2-does-create-warming/#comment-26002
http://blogs.discovermagazine.com/badastronomy/2010/04/09/im-your-venus-im-your-fire/#comment-258111
http://scienceofdoom.com/2010/04/09/sensible-heat-latent-heat-and-radiation/#comment-1382
Hope you have better luck.
See Soden and Held, 2000. http://www.gfdl.noaa.gov/bibliography/related_files/annrev00.pdf The bit above and below figure 1.
This is an interesting comment thread, too.
http://noconsensus.wordpress.com/2009/12/05/it-is-what-it-is-and-the-god-of-physics-will-have-it-no-other-way/
“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.”
It is not hard to find figures that say more like 80% of the sunshine is reflected into space. That leaves 20% of the sunshine to get in and raise temperatures to the melting point of lead!
I am inclined to go with the much higher albedo than S. Goddard has cautiously cited. For one thing, Venus is the 3rd brightest object in the sky after the Sun and Moon, with its greatest magnitude being 4.6.
Hard to believe that twinkling beauty is a place where you would be fried, poisoned, squashed and corroded. I suppose there could be a lesson in there somewhere, but it isn’t the “runaway greenhouse effect”!
The EPA say: “Were Venus’ atmosphere to be transparent to radiation, then the surface temperature of Venus would be determined only by the blackbody radiation of the surface, and the pressure of the atmosphere would not change this equilibrium temperature. There is a large body of literature on Venus’ climate; one example is Bullock and Grinspoon (2001)—all of which show that CO2 is a significant contributor to the planet’s warmth. “
See Soden and Held.
http://www.gfdl.noaa.gov/bibliography/related_files/annrev00.pdf
sHx says:
May 6, 2010 at 3:26 pm
“…..Hansen, it seems, re-imagined Earth climate system in Venusian terms. His obsession with CO2 and runaway greenhouse effect originates from his early expertise in Venusian atmosphere. This is a mere speculation, but I don’t think we would have this runaway AGW scare had a Venus specialist not been in charge of NASA GISS.”
_______________________________________________________________________
CAGW comes from the first Earth Summit and Maurice Strong in 1972. As Elaine Dewar wrote in Toronto’s Saturday Night magazine:
“It is instructive to read Strong’s 1972 Stockholm speech and compare it with the issues of Earth Summit 1992. Strong warned urgently about global warming, the devastation of forests, the loss of biodiversity, polluted oceans, the population time bomb. Then as now, he invited to the conference the brand-new environmental NGOs [non-governmental organizations]: he gave them money to come; they were invited to raise hell at home. After Stockholm, environment issues became part of the administrative framework in Canada, the U.S., Britain, and Europe.”
http://www.mail-archive.com/ctrl@listserv.aol.com/msg106963.html
Strong is a member of the Club of Rome.
Club of Rome Document, 1991, “The First Global Revolution” p. 71,75 1993
– Richard Haass,
“The common enemy of humanity is man.
In searching for a new enemy to unite us, we came up
with the idea that pollution, the threat of global warming,
water shortages, famine and the like would fit the bill. All these
dangers are caused by human intervention, and it is only through
changed attitudes and behavior that they can be overcome.
The real enemy then, is humanity itself.”
Strong is a trustee of the Rockefeller Foundation and worked for the Rockefellers in Saudi Arabia when he first started out. Even David Rockefeller had the gall to admit they are trying to wreck the USA. He writes in the Rockefeller autobiography “Memoirs” on page 405, “For more than a century ideological extremists at either end of the political spectrum have seized upon well-publicized incidents… to attack the Rockefeller family for the inordinate influence they claim we wield over American political and economic institutions. Some even believe we are part of a secret cabal working against the best interests of the United States, characterizing my family and me as “internationalists and of conspiring with others around the world … If that’s the charge, I stand guilty, and I am proud of it.”
There is plenty of evidence that CAGW and the anti-nuclear movements were orchestrated for political and monetary motives. Both Strong and the Rockefellers are heavily into oil and did not want nuclear as a competitor in the 1970’s
One of the things overlooked is that Venus has an opaque atmosphere. That means that energy can only be radiated from the very edge of the atmosphere, unlike Earth, where a photon can fire out from just about anywhere from the surface upwards. That makes the effective surface area of Earth (and Mars) very large, and the effective surface area of Venus very small in comparison.
Combine this with the increased albedo of Venus – recognising that the whiter a surface, the less it radiates – and you can see that Venus probably has a hard time dumping heat, especially in comparison to Earth and Mars.
A little bit of geothermal energy probably goes a long way there – I’m not surprised the surface periodically melts.
I think Venus and earth have nothing in common. Youve gotta ask the why with the thick atmosphere of venus, vrs earth. And water is the obvious difference… which enables chemical reactions that lock co2 from the core outta the atmosphere. So venus would have been of similar composition at its birth, with its location in the solar system, but the main difference that i can see that would result in the H2O being stripped would be the absence of a magnetic field on venus, the result i suppose of its slow rotation/long days… which would have meant that the solar winds would have stripped the atmosphere/planet of lighter gases.
If earth had all the co2 in its atmosphere today that had been vented from its core since its birth, id wager it would also have a dense atmosphere. And be a tad warmer than it is now;-)
And it dosnt matter if the shortwave dosnt reach the surface, if its absorbed in the atmosphere, it will still cause a greenhouse effect.
@ur momisugly kramer says:
May 6, 2010 at 2:46 pm
I think the 3rd poster (Curiousgeorge ) has a good point.
Well, thanks; but the point was merely to get people thinking a bit. I know full well that Venus does not behave as a cylinder does. It has sources of energy, including tidal effects, possibly some internal radiation, etc. as well as solar heating & volcanism that effectively keep those gas molecules moving and therefore keep the energy level up. And that’s really what we’re talking about here – energy.
It’s theorized that Titan has liquid water under it’s miles of ice due to heating from the tidal effects of Jupiter, so Solar tidal effects may not be an insignificant factor on Venus, especially given it’s slow rotation.
Stunningly obvious.
Stunningly simple.
And stunningly ignored.
You might want to make a calculation of “radiation transmitted by the atmosphere” on Venus (as shown above for Earth); You will be surprised by what you see. There is essentially as much water (absolute) on Venus as on earth (yes it is a smaller fraction of the atmosphere, but the atmosphere is ~100 times more massive); in addition, the much higher pressures broaden the IR transitions (both for water and CO2) producing a very thick greenhouse. The presence of sulfur dioxide and sulfuric acid add additional opacity.
Congratulations Steve.
Now ask this really interesting question:
At what temperature does Calcium Carbonate thermally disassociate into Carbon Dioxide and Calcium Oxide? Notice that this temperature is way above the surface temperature of Venus and so limestone would be a thermally stable rock, even on Venus. (OK, I know, but not chemically stable in the presence of the sulphuric acid in the Venusian atmosphere).
The real point is this. It is not possible for the carbon dioxide sequestered in the limestone rocks of Earth to be naturally released into our atmosphere by thermal dissociation of limestone (except of course in a cement works). In order to load our atmosphere with the equivalent mass of Carbon Dioxide gas seen on Venus, all of the limestone on Earth would have to be destroyed.
You are right Steve. For the Earth, runaway carbon dioxide greenhouse is a complete fiction.
It is 9000 KPa on earth. Deep under the mantle. I wonder if it is cool there?
As Rob above explained you are looking only at the present conditions and not how Venus’s atmosphere evolved. The Wikipedia article you cite does explain this.
“Studies have suggested that several billion years ago Venus’s atmosphere was much more like Earth’s than it is now, and that there were probably substantial quantities of liquid water on the surface, but a runaway greenhouse effect was caused by the evaporation of that original water, which generated a critical level of greenhouse gases in its atmosphere. [34]”
http://en.wikipedia.org/wiki/Venus#Atmosphere_and_climate
The reference is to one paper that uses a one-dimensional model and requires a subscription. Does anyone have a better reference for the evolution of the Venusian atmosphere? It may be that the high temps caused even more CO2 to go into the atmosphere and increase the density. Anyone know?
phlogiston says:
May 6, 2010 at 3:35 pm
The distance from the Sun has to do how much energy reaches a planet.
What happens from there is the subject.
Magnetic field vs how much early Solar Wind scouring has taken place. Mass counts as radioactive material decay can internally heat a planet. Have a look at the density of and mass of the inner planets.
The greenhouse effect is not the only thing that makes objects hot in the universe.
Gravitation compression causes Jupiter’s core to be 24,000K, Earth’s core to be over 6,000K, and for the stars to initiate main sequence nuclear fusion, temperatures have to increase to 10 million Kelvin (no greenhouse effect involved in that).
Furthermore, some of the hottest places on Earth are the depressions below sea level. The Dead Sea for example is about 5C to 7C warmer than the temperatures above the rift valley (a higher rate than would be expected from the lapse rate alone at 2C to 4C).
Obviously, it is not as easy as just “pressure”. The deep ocean has a temperature close to 1.0C despite the very high pressure in the deep ocean but that is because water is denser as it get colder. The hottest temperatures in the Earth system are, in fact, at the very top of the atmosphere in the Thermosphere because it is subject to so much EM radiation from the Sun and the magnetic field (and the fact that it is so thin, temperature starts to mean less and less).
If you look at the lapse rate of Mars, Earth, Venus and the Sun, it has a logarithmic relationship to temperature with higher lapse rates occuring as the temperature increases but it is logarithmic.
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.
Savante says:
“There is essentially as much water (absolute) on Venus as on earth”
Are you sure about this…..i take it this isnt counting H2SO4 as water… can you cite a source please?
“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.
What does balance it, of course, is thermal IR emitted from the atmosphere itself. But that can only happen with some GHG effect.
The adiabatic transport effect can explain a temperature difference. But it can’t provide that source of radiant heat. All it means is that TOA would be correspondingly colder.
“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.”
It doesn’t have to involve the ground. It only requires that heat passes through a layer of gas at a frequency to which the gas is relatively transparent, and is part-blocked from returning at lower thermal IR frequency. It doesn’t matter whether the absorption and reemission happens at the ground or at a lower level of the atmosphere.
OT:
I was watching UK Channel Four’s Alternative Election Night programme and they brought on trendy, all-over-telly-at-the-moment, Prof. Brian Cox and asked him what we SHOULD be worried about. He had a list of five things and as I was expecting the obligatory CAGW, probably as No.1 “threat”, I frankly zoned out a bit, but shockingly, amongst super volcanoes, plagues and asteroids, I don’t think there was a single mention of global warming. Even when he came to his No 1, human stupidity, I didn’t hear anything about AGW.
Did my ears deceive me? Anyone else catch this? Doesn’t he realise that even the fact of not mentioning AGW will cause him to be banished to the wilderness – or is he a closet sceptic?
Surely if he was any kind of believer, AGW would be in his top 5 threats to humanity?
I know it sounds like a minor point but, given the non-stop gushing about AGW on British TV this was genuinely a surprise.
Onion,
CO2 has a very narrow bandwidth for absorption of IR radiation. Unlike the earth with oxygen, ozone, water vapor, and a couple other high efficiency radiation absorbers that are wide band, the CO2 atmosphere of Venus is like stretching a few reflective strings over a wide open window to try and reflect back the energy.
Steve,
Thanks and that would mean that while CO2 on Venus is a fifteenth the density of water, air on earth (at 1.2 kg/m3) is only about one *fiftieth* the density of CO2 on Venus. I wonder if you’d call movement of something that heavy – a wind or a current. I also wonder what convective processes would be like on Venus.
Savante,
“…adds additional opacity.”
Opacity means BLOCKED. Doesn’t mean reradiated in all directions which is the so called Greenhouse theory.
Like earth there is still the issue as to whether a cooler atmosphere CAN heat a hotter surface!!!!!!!!
How high is the tropopause on Venus again??
How much water vapor is actually below the tropopause??
By the way, there is no confirmation of actual water only hydroxyl.
http://www.ilovemycarbondioxide.com/pdf/Rethinking_the_greenhouse_effect.pdf
If there was a lot of heat coming out of the interior of Venus, it would be detectable as a radiative imbalance at the exterior of the atmosphere. Has anyone heard of this? I haven’t.
I had to explain this to a few people while working with turbos, so let me try to throw some plain English explanations into the mix.
When you compress ambient air with a turbocharger, it gets hot. Really hot. Most people simply use the logic that the turbo is hot (driven by exhaust gas), therefore it heats the air. This isn’t even remotely close, since the air isn’t in contact with the blades nearly long enough to heat it much. What is happening is that all of the energy that was already in the air is now packed into a smaller space, thus there is more energy in the same space, thus it is warmer.
And by warmer, I mean really warmer, hundreds of degrees. This is why turbo cars use an intercooler, a mini radiator that lets the compressed air radiate much of that heat before it gets into the engine.
The post above about compressing air into a bottle heating it but then later it’s cool? The simple reason is that the energy has radiated away. If you compress air into a thermally isolated chamber it will remain warmer (don’t try a Thermos, they can’t take much pressure… voice of experience).
As we all know, the atmosphere of Earth holds only a tiny fraction of the energy that the oceans do. The exact same is true of the Venusian atmosphere: it is under a higher pressure and therefore CAN hold more energy. So it does. And it gets that energy from the local star. Who knows how long it has taken to reach its current equilibrium? Are there Venusian Climatologists right now worried about 10K temperature variations over the last century?
Ironically, we use the stereotype of Mars being red, angry, male, and Venus being gentle, mellow, female. In actuality Mars is cold, barren, dull, and Venus is hot, roiling, active.
Nick Stokes
You set up a straw man using a selectively edited quote. Very naughty of you.
What I wrote was :