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
Lon Hocker:
“It would appear, since the energy balance isn’t at the surface on Venus, but way up in the atmosphere, that something is holding the heat in. This is usually called the greenhouse effect. If you can find a flaw in this argument, please let me know.”
Gravity prevents the atmosphere from escaping to space. The density of the atmosphere dictates how much energy the constituents can hold before re radiating again. It doesn’t matter where the point of radiative balance lies.
You can call it a greenhouse effect if you wish (annoyingly many do) but that’s a misleading description because it suggests something akin to the huge heating effect caused by restraining convection within a glass structure. It’s nothing like that. It’s just a slowing down of energy through the system and unless one increases density there will be no additional slowing down. CO2 is far too small a component of Earth’s atmosphere for any conceivable increase from human activity to measurably affect total atmospheric density.
Even if it could do so the oceans neutralise the effect of any minor changes of density in the air via the far greater influence of what I have called ‘The Hot Water Bottle Effect’.
http://climaterealists.com/index.php?id=1487&linkbox=true&position=3
It’s not just the air that has that gravity/density effect in slowing down the passage of energy through the system. The oceans possess it too to a far greater degree.
In fact one could say that the level at which the equilibrium temperature is set for the Earth is actually the ocean surface. The mistake people make is regarding the radiative balance in the air alone as all important. It isn’t. The ocean surfaces control the availability of energy to travel up through the air above. The ocean proposes and the air is merely it’s servant.
“Andrew W says:
May 8, 2010 at 1:39 pm
Stephen Wilde, the pressure at the surface will remain the same whatever state the matter above it is in, only by changing gravity or the amount of matter above the surface will the pressure change.”
Re read my post especially:
How would you propose to halve the temperature without altering gravity and density ?
If the gas were to liquify or freeze how would you prevent it from dropping out of the atmosphere thereby reducing density, temperature and pressure ?
Please note that all my comments here relate only to the basic equilibrium temperature of a planetary atmosphere as a whole.
There are lots of mechanisms arising from internal system variability that operate to vary that base temperature over time.
Anyway the basic point made by Steve Goddard is perfectly correct.
Steve Goddard said “If 90% of the CO2 in Venus atmosphere was replaced by Nitrogen, it would change temperatures there by only a few tens of degrees.”
Yep, but others have commented, replace all of the GH gases with non GH gases and the surface temperature would plummet to that of a black body.
When we talk about the runaway GH effect on Venus we’re also talking about the process that created the atmosphere that that planet now has.
The CO2 now in the Venusian atmosphere came from the O in H2O and the C baked out of the planets surface by the temperature that resulted from the GH effect of the water vapour that, further from the sun, would have been a Venusian ocean.
Andrew W
May 8, 2010 at 2:22 pm
“Steve Goddard said “If 90% of the CO2 in Venus atmosphere was replaced by Nitrogen, it would change temperatures there by only a few tens of degrees.”
I’d guess he is right. So much of the density of the Venusian atmosphere is comprised of other gunk such as sulphuric acid clouds that removing 90% of the CO2 wouldn’t make much difference even if you didn’t bother to replace it with anything.
“The CO2 now in the Venusian atmosphere came from the O in H2O and the C baked out of the planets surface by the temperature that resulted from the GH effect of the water vapour that, further from the sun, would have been a Venusian ocean.”
Quite so. If Venus had retained water oceans like ours the hydrological cycle would have stripped out all that gunk and the density of the atmosphere would have been far lower with a much reduced Venusian temperature.
In other words we have nothing to fear until our oceans boil dry and perversely the AGW crowd say the oceans will get bigger !!
Go figure.
Andrew W, no less than King of the Warmists, NASA Scientist James Hansen, promotes the “Earth will turn into Venus” concept!
Here’s a 2008 presentation paper: http://www.mediafire.com/?trm9gnmznde
Page 22 of 39, Dr. Hansen says:
“The Venus syndrome is the greatest threat to the planet, to humanity’s continued existence.”
Good enough for ya? What is this guy THINKING??
CRS, Dr.P.H.
So you can’t name a “serious scientist” making such a claim, Pearson certainly does not claim Earth faces a Venus type runaway GH effect, just that some insights might be gained by studying Venus, and a Ph.D in Industrial and Business Studies doesn’t even make him a scientist.
Steven at 6 am
you stated
“I understand what you are saying. My point is that the reason CO2 saturates the infrared spectrum on Venus is because of the high pressure. Without the high pressure, it wouldn’t happen.”
Steven, one of the problems with the warmists is that they have become ideologically committed to a theory to the point that they cannot let go even in the face of very significant contrary evidence. Please don’t make the same mistake. Your comment above distorts what several people have been saying on this blog, me included. The reason CO2 saturates the infra red spectrum is because there is such a huge amount of it in the atmosphere of Venus. The pressure is a consequence of the amount of CO2 present. If Venus had the same pressure but it was all due to nitrogen rather than CO2 the temperature would be far lower. If it was mainly due to nitrogen with a trace of CO2 it would also be lower.
I agree that a dense deep atmosphere predisposes to higher surface temperatures as you claim but you are going further and claiming that this is the entire, or at least the principle, reason for the very high surface temperature on Venus. The reality is that GHG effect from CO2 is a major factor. The massively broadened absorption bands of CO2 block radiation to space which means the surface can only lose heat through convection/conduction and that requires a more or less constant temperature
gradient as others have pointed out. However, don’t lose sight of the fact that the energy has to be lost by conduction/convection because of the massive greenhouse effect from CO2.
If Earth had to rely totally on conduction/convection in order to lose energy even with our current atmospheric pressure, the temperature on Earth would be very significantly higher. It is not because a large portion of the energy is lost by direct radiation to space in the atmospheric window. Having said that, any comparison between Earth and Venus is pointless because to bring about a Venus type situation you would have to convert essntially all the oxygen on the planet to CO2 and we would all be dead from lack of oxygen. Such a situation could not come about by any conceivable level of burning of fossil fuels so the comparison is irrelevant.
Robert Hafer at 12:55 “Supercritical CO2 is neither a liquid nor a gas. It’s a separate state of matter.” Sorry Robert but this is rubbish. supercritical CO2 is simply a liquid like any other liquid. Pressure temperature phase transition diagrams were a strighforward part of 1st year uni chemistry at least when I did it. What you may not realise is that the same situation exists in all refrigerators and air conditioners. The gas is not CO2 because the transitions occur at incoveniently high pressures. Instead they use hydro fluro chlorocarbons(HFC’s) (used to use freon before the greenies). This is compressed until it liquifies. When it does so the latent heat of condensation is released and disposed of to the environment via a radiator and fan. The liquid is then pumped into the room, the pressure allowed to drop at which time the liquid evaporate again. As it evaporates it absorbs the latent heat of evaporation which of course extracts heat from the room cooling it. The gas then returns to the compressor and the cycle repeats. You can do exactly the same thing with water if you pick the pressure and temperature regime accordingly. At low enough pressure the boiling point of water can fall so low that it is below 0C and water can transition straight from ice to water vapour missing the liquid phase. It called sublimation and by the way it occurs in all frost free freezers not because the pressure is so low but because the water vapour pressure is so low.
Andrew W says:
May 8, 2010 at 2:38 pm
CRS, Dr.P.H.
So you can’t name a “serious scientist” making such a claim, Pearson certainly does not claim Earth faces a Venus type runaway GH effect, just that some insights might be gained by studying Venus, and a Ph.D in Industrial and Business Studies doesn’t even make him a scientist.
—–
REPLY: Download and read Hansen’s paper.
Queen takes pawn, checkmate.
http://www.mediafire.com/?trm9gnmznde
Good point CRS, Dr.P.H.
I’d point out that Hansen is talking about burning all the coal on the planet to lift CO2 concentrations to ~ 4000ppm. That’s not going to happen.
Hansen also once used geometric progression to argue that a sea level rise way above the IPCC forecasts was possible, on another forum I said that he was using a “bloody stupid” argument, as he is in this case.
Michael Hammer said:
“If Venus had the same pressure but it was all due to nitrogen rather than CO2 the temperature would be far lower. If it was mainly due to nitrogen with a trace of CO2 it would also be lower.”
Is that right ?
Surely the temperature in a Nitrogen atmosphere with the same number of molecules as the CO2 atmosphere would have both a lower pressure AND a lower temperature because the mass of Nitrogen molecules is so much less than the mass of CO2 molecules ?
To get the same pressure from a Nitrogen atmosphere you would need a vastly greater quantity of Nitrogen and if you achieved the same pressure by such means then you would get the same temperature too.
Stevengoddard & ALL: Here is an authoritative extract from the ESA, (my bold), so let’s examine it, particularly as to why Venus has a uniform average temperature everywhere. (over117 earth days, and see link below)
“…[1] On Venus there are no day and night variations of the surface temperature. The heat is globally ‘trapped’ under the carbon-dioxide atmosphere, with pressure 90 times higher than on Earth.
[2] Instead, the main temperature variation is due to topography. Just like on Earth, mountain tops are colder, whereas the lowlands are warmer. The ‘only’ difference is that on Venus ‘cold’ means 447º Celsius, while ‘warm’ means 477º Celsius. Such high temperatures are caused by the strongest greenhouse effect found in the Solar System…”
[1a] When facing the sun, she is said to receive at the surface about 10% of sunlight. Whether this is a midday or total facing area average, or the effects of scattering, I don’t know, but whatever, the surface receives SOME solar energy. This energy amount must be lost back to space because the planet is apparently in thermal equilibrium. The fundamental process for this should be convection and conduction. Additionally, since infrared photography etc of the surface has been accomplished there is at least one window for some infrared to directly escape to space.
[1b] At nightime she no longer receives any solar energy, but has capability to lose heat in the same way as on the daylight side, over a period 117 times longer than on Earth. What is more, because the upper atmosphere is no longer heated by solar infrared, (~40% of sunlight), the temperature gradient of the atmosphere should increase, inferring increased conductive/convective cooling. Yet, there is no change in surface temperature! Such a condition would require an impossible perfect insulation layer, and no geothermal energy, but clearly, this is not the case.
[2] This part of the extract supports Steven’s hypothesis, but see also my comment above concerning the strange and unexplained dynamics of the atmosphere, according to the ESA. (that may have an astonishing “mixing” effect).
In my post of a few minutes ago, I forgot to ask if anyone still believes that the high surface temperature is the consequence of a greenhouse effect, despite the authoritative assertions of NASA and ESA etc?
Andrew W, Hansen actually goes quite far and extrapolates to burning all coal, and then tar sands etc.
p. 24/39: Hansen says “In my opinion, if we burn all the coal, there is a good chance that we will initiate the runaway greenhouse effect. If we also burn the tar sands and tar shale (a.k.a. oil shale), I think it is a dead certainty. ”
He’s quite extreme in his position on “runaway” GH effect, perhaps because he studied the atmosphere of Venus at the beginning of his career.
Ya know, we wouldn’t be in such a position if the Democrats/greens hadn’t kept killing off nuclear power! Clinton admin killed the amazing, inherently safe sodium-cooled “fast” reactor design from Argonne Labs, and Obama admin put the final nail into the coffin by shuttering Yucca Mountain forever. Not many fuel choices left.
First of all I am just a simple construction worker that has read all the comments on this issue.
Now I am more confussed. so I have some questions?
If CO2 blocks IR why is the surface so warm but the upper atmostshere cooler? (where is the hot spot)
Why is it a bit warmer on the darkside of Venus. Night lasts 50+days? (even a super CO2 blanket can’t make it warmer)
Shouldn’t we be comparing the heat content, not the temp. I rather put my hand into dry air at 100c than water at 100c.
Thanks Ian
NLBMN – UHK
(No Letters Behind My Name -University of Hard Knocks)
michael hammer
A supercritical fluid is not “a liquid like any other”. Please see http://en.wikipedia.org/wiki/Supercritical_fluid
for a brief background. A supercritical fluid occurs past where the liquid/gas phase boundary ends. It has some gas properties, some of liquid and some unique. It will not conform to the Ideal Gas Law but it will compress, in most cases.
They threw Venus probes data out!
Another black mark in science
Velikovsky’s Comet Venus
http://thunderbolts.info/tpod/2010/arch10/100312cometvenus.htm
http://www.templeforkflyrods.com/products/conventional.html
“”” Pamela Gray says:
May 6, 2010 at 6:57 pm
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!!!! “””
Pamela dear, hyperventilating Redheads are something else; ain’t they !
So check out the link to TFO above; as in Temple Fork Outfitters. I’ll bet they have exactly the rod you are looking for. They are an all America Texas outfit of very nice folks. All their rods are designed in America, and built exclusively for them in South Korea.
Go to that link and check customer service, so you can e-mail them. Ask for either Jim Shulin, or Rick Pope who is the President; and tell them that I sent you there; and I bet they can take care of your needs; so you can quit that hyperventilating.
My son happened to buy the very first TFO rod ever sold on the West Coast; and we have been using almost nothing else since.
Lifetime guarantee; if you break it they will replace it, for just the shipping cost. I’ve got more of them than I know what to do with; and the only one I have ever broken, I blew up in my back yard by hanging 14 pounds of salmon trolling balls on it while it was sitting up on an A-frame ladder. Well you wouldn’t be doing that with your trout rod; but they make good affordable stuff.
Don’t forget to tell them I sent you, so they’ll know to take care of you.
And no I don’t get anything out of it, besides contemplating you hyperventilating.
George
What is happening here?
My 2 last comments have been removed?
For what reason?
And what makes this a scientific site?
Jon-Anders Grannes says:
May 12, 2010 at 9:12 am
What is happening here?
My 2 last comments have been removed?
_______________________________________________________________
Both your other comments are there. This blog gets a lot of comments on several articles so there is a lag time. Please remember the moderators are all volunteers not paid employees.
You know where else the pressure is extremely high? The bottom of the ocean. Hey, it even receives next to no sunlight, just like Venus’ surface! I bet it’s extremely hot down there!
As well it should.
Bingo.
Ben Schumacher
“As far as I can see, the ONLY way to explain this is that the atmosphere of Venus strongly absorbs IR. ”
The problem with your interpretation is this: IF the clouds are absorbing all this energy where is it going? The clouds themselves would radiate and become part of the radiating surface, shedding a huge amount of energy back into space because the clouds themselves are not behind a green house layer.
Basically you cannot have an average surface temperature (in this case clouds are a portion of the ‘surface) MORE than the black body temperature. Hot surface temps, EVEN AT NIGHT simply don’t make sense without another energy source.
The pressure argument here is irrelevant, though. Pressure does not cause heat (compressing uncompressed gas concentrates heat, which is eventually shed).
jay Reur May 13, 2010 at 9:45 am
But with bottom heating, (very hot surface), convection takes place and there is constantly descending gas, which is recompressed
Joey Joe Joe Jr. Shabedeaux Reur May 12, 2010 at 10:00 am
Water is incompressible, unlike a gas.
Try it out with the bicycle pump analogy.
The usual IR absorption model of CO2 to explain a hot Venus is, like many other explanations, overly simplistic. Although Venus has an high albedo, most of the solar radiation that is absorbed certainly is by the Venusian atmosphere, thus the upper atmosphere above the subsolar point MUST BE WARMER than farther away where CO2 without anything above it is radiating into space. This causes increased scale height above the subsolar point, and will result in a general flow in the upper atmosphere away from this area, and gases will rise from the lower atmosphere as a result. Away from the subsolar point where the scale height is much lower, upper atmosphere components must descend, and undergo adiabatic compression, heating them according to the adiabatic gas equations. p1v1**gamma=p2v**gamma. This will heat the descending air like the compression phase in a diesel engine.
Radiative transfer is very slow with all the CO2, and thermal inertia from the huge mass of atmosphere keeps surface temperatures fairly constant even through the very very long Venusian night. It is not true that temperatures are constant on the surface, by the way, though the variation is slight.