Runaway warming on Venus?

[Lucy Skywalker]

I'm going to introduce myself first. Then I can always refer back here.

I've come over from the climate skeptics' world to look at Electric Universe material. I was inspired by seeing a polarization between talented people, both noisily for and noisily against - but without going back to first principles myself, I had no idea whether to believe or not. It would be better to say I am not by preference a believer, I like to check evidence.

I finally had time to read Donald Scott's online pages of introduction. I'm entranced with the EU hypothesis, at least to explain the physical universe as is, now. Regarding origins, and connections with myths, I'm not going to opinionate because I haven't yet found out what is being put forward here. But the basic physical hypothesis strikes me as being like Cinderella's Shoe - it fits, and fits beautifully, unlike all other attempts, when it comes to anything beyond our own troposphere.

I became so enthusiastic that before I lost the impetus, I decided to write a page to add to my own collection of pages on Climate Science and the current scam.
http://www.greenworldtrust.org.uk/Science/Curious.htm Curious about Climate Science
http://www.greenworldtrust.org.uk/Scien ... iverse.htm Braving the Electric Universe hypothesis
Then out of courtesy I wrote to Don Scott to appraise him and check, and I received back an incredible welcome from Dave Smith and others. I was gobsmacked!

Now what I'm getting very interested in is what one could call "Science at the Crossroads". In the mainstream science, everything on the fringe is shoddily, unjustly and noisily debunked, misrepresented, and suppressed. Wikipedia is not your friend in such areas. But having said that, I'm also highly wary of fringe material and its "devotees". I try always to keep to the high road of Scientific Method - but with the understanding that Scientific Method can apply equally to matters of psyche and spirit as to physical matters - the development of psychology is one testimony to that.

I'm still pretty passionate about Climate Science, as I feel that what I can do there to help redeem Climate Science almost always has wider implications that are both human and transcendent. So when I realized I wanted to take on board positive affirmation of EU, I realized I needed to check out the issues that have rankled with those against EU, so that I can cover my backside with good, open, checkable Science, good ol'fashioned courtesy, not claiming areas of ignorance as areas of knowledge, discerning between areas of agreement and disagreement, etc.

Leif Svalgaard kindly pointed out one of the main "debunks" of the EU hypothesis, for which I am grateful. He did not, however, point out Scott's answer, for which unfairness I deduct marks. This is how it goes.

Another issue I discovered was references in the EU world (I'm not even sure exactly where, now!) to the "fact" that Venus is emitting more energy than it receives via solar energy, and that this has been measured by Pioneer / Venera probes. Now for Climate Science, this is a highly significant piece of information.

James Hansen is one of mainstream Climate Science's big bully boys, in effect. His training is astrophysics; what started him off on his "catastrophic global warming" jeremiad was his belief that Venus was suffering from runaway greenhouse gas warming from its CO2 mantle. Now if Venus is actually emitting surplus heat, this completely undermines Hansen's belief. AND - Hansen must surely have known this for years. Or if not, why not? Is this piece of evidence available to ordinary folk like me? All I want is a checkable reference to source.

Any help on this matter gratefully received.

PS I did search the Forum but found nothing. I hope this is the right place and way to ask!

[nick c]

Lucy Skywalker,
Welcome to the Thunderbolts fourm (and may the force be with you ).
That is a very astute observation on your part, indeed, the whole idea of global warming on Earth stems from the concept that Venus, which is often described as our sister world, is the 'victim' of a runaway greenhouse.
The Electric Universe postulates that Venus' heat is not the result of a greenhouse effect but rather the result of it being a young planet with a different history than that of the Earth, and that it is in the process of cooling down.
Venus Isn't Our Twin!

Nick

[Lucy Skywalker]

Thank you Nick. Thanks for your kind words and welcome.

I have read Wal Thornhill's piece you link to, about Venus. It does not give any reference I can track back. I've ordered his books and perhaps I will find references there. Meanwhile, I keep on finding I want to refer to this stunning fact on my climate science blogs, but am hesitant to do so without backup data / references.

[Solar]

Hello Lucy Skywalker. Here are some of the missions. It is interesting that the first one (Venera 8) found the light level suitable for surface photography despite "a very high surface temperature."

Venera 8
Successful Venus lander (USSR)
Launch: March 27, 1972
Venus landing: July 22, 1972
Upon Venus arrival Venera 8 used aerobraking to decelerate, and then deployed a parachute. A refrigeration unit cooled the spacecraft's components, protecting them from the intense heat as the lander descended to the surface. Once on the ground, the spacecraft transmitted data for 50 minutes, confirming a very high surface temperature and crushing atmospheric pressure. It also measured the light level on Venus’ surface and found it suitable for surface photography, setting the stage for the images to be returned by Venera 9, 10, 13, and 14.


Venera 13
Successful Venus orbiter and lander (USSR)
Launch: October 30, 1981
Venus arrival: March 1, 1982
Venera 13 returned the first color images from the surface of Venus, landing at 7.5° S, 303° E. A drilling arm collected a sample that was examined by an onboard x-ray fluorescence spectrometer to determine its composition. The lander survived 127 minutes before giving in to the extreme heat (457°C) and the tremendous pressure (84 times the pressure at sea level on Earth).

Venera 14
Successful Venus orbiter and lander (USSR)
Launch: November 4, 1981
Venus arrival: March 5, 1982
Venera 14 sent back images of the surface and a mechanical arm collected a sample for testing. The spacecraft survived for 57 minutes before succumbing to the heat and extreme pressure.

Pioneer Venus 1 (Pioneer Venus Orbiter)
Successful Venus orbiter (NASA)
Launch: May 20, 1978
Venus orbit insertion: December 4, 1978
Pioneer Venus 1 carried 17 experiments, including a radar mapper. Scientists used the radar to map nearly the entire planet, resolving features as small as 80 kilometers (50 miles). The spacecraft remained in orbit until August of 1992, when it used up all its fuel and burnt up in the atmosphere.

Pioneer Venus 2 (Pioneer Venus Multiprobe)
Four successful Venus probes (NASA)
Launch: August 8, 1978
Venus arrival: December 9, 1978
Pioneer Venus 2 consisted of four separate atmospheric probes; one large probe 1.5 meters in diameter, which deployed a parachute to slow its descent, and three small probes (0.8 meters or 2.6 feet across) which plunged straight through the atmosphere. The large probe was released from the spacecraft bus on November 16, 1978. The three smaller probes were released four days later. All of the probes arrived at Venus on December 9, 1978. Each probe took atmospheric measurements as they descended through the cloud layer. One of the probes survived to transmit data for over an hour after it impacted with the surface. The spacecraft bus that carried the probes also had instruments and made measurements in Venus’ uppermost atmosphere before burning up.

Missions to Venus: Planetary Society

[DustyDevil]

Welcome, Lucy Skywalker!

Here's a link to a web page written by Ted Holden which gives references that you can track down:

http://www.skepticfiles.org/neocat/equalib.htm

You can find the New Scientist article from Nov. 13, 1980 called "The mystery of Venus's internal heat" by searching Google Books using this search "venus radiates more heat then receives".

Good luck with your search.

DD

[Lucy Skywalker]

Done and dusted, Dusty Devil. Thanks a lot, you did provide what I was looking for. Well, enough for the mo.

New Scientist April 1980

New Scientist Nov 1980

.

Oh bother. the pics are too small and I don't know how to increase their size. Look at them here instead:
http://img227.imageshack.us/i/newsciapr80.jpg/
http://img814.imageshack.us/i/newscinov80.jpg/

Ted Holden's article is very interesting, I like most of it, and I've edited it into a statement I can support. However the website of which it is part has some very strange sections, not all is to my liking!

[fosborn]

Solar » Jan 19th, '11, 22:11 noted:
Pioneer Venus 2 (Pioneer Venus Multiprobe)
One of the probes survived to transmit data for over an hour after it impacted with the surface. The spacecraft bus that carried the probes also had instruments and made measurements in Venus’ uppermost atmosphere before burning up.

I had read some article that said they considered the surface probe temperature data ( under atmospheric data, I assume that's what it would be under) invalid. So I wanted to look it up for myself and this is the results;

"These data are being held by and are available from Dr. Roger Craig at NASA Ames Research Center, Moffett Field CA."
http://nssdc.gsfc.nasa.gov/nmc/datasetD ... PSPA-00397

I didn't try to contact anybody to ask for it. But what is the big deal about not having it readily accessible?

[Lucy Skywalker]

what is the big deal about not having it readily accessible?

As the pics above show, I found it fascinating that the April 1980 issue of New Scientist had an op-ed by John Gribbin "Fools Rush In" which contained these words: "What we don't hear from the [Velikovsky] fans is news of all the predictions that have fallen flat on their faces - that both Venus and Mars would be found to radiate more heat than they receive from the Sun, for example..." Then the November issue has an embarrassed piece suggesting that Venus DOES radiate more.

So - there is an emotional vested interest in NOT finding evidence of Venus radiating more heat than it receives, in mainstream science. But I sense a liability to an opposite emotional vested interest in FINDING evidence, amongst Velikovsky supporters, and here. Certainly, one of my first pro-EU posts on the Climate Skeptics forum Watts Up With That, was talking about Venus radiating heat therefore its runaway Greenhouse Gas idea falls apart - and unusually for me, I was saying this without being able to provide proper references. Then when I looked I found John Ackerman's paper and quoted that. Then I had doubts about Ackerman. Then when I Googled openly, I found, as feared, various references to EU people citing this about Venus as "fact" when it was just wishful thinking - and still I found no hard references until Dust Devil supplied them. For a while I feared I was making myself look a fool by claiming things without proper citation, that others say have been debunked and are rubbish.

Yet I still suspected that there was hard evidence that Venus is a net exporter of energy. IF I COULD FIND IT!!!!! Dust Devil's references show at the very least that it is highly likely that Venus is indeed exporting energy, and that there are vested interests to try as far as possible to deny the evidence of this. It's worth stating what I found from Ted Holden, because this explains nicely the nuances to the picture, where both sides can claim to be "unequivocally" correct.

Dust Devil is in the Details!

Here is my rewrite of Ted Holden's piece http://www.skepticfiles.org/neocat/equalib.htm He claims that evidence involving Venus is being doctored because it does not fit with scientists' pre-conceived ideas and does not match the requirements of Carl Sagan's "super-greenhouse" theory. I've edited his piece to present my own stance - which is pretty well Holden's, minus his theory of origins, and minus some hyperbole.

"Super-Greenhouse" requires that Venus be in thermal equilibrium. But is it?

The Nov. 13 1980 issue of New Scientist contained an article entitled "The mystery of Venus' internal heat", which read as follows:

Two years surveillance by the Pioneer Venus orbiter seems to show that Venus is radiating away more energy than it receives from the sun. If this surprising result is confirmed, it means that the planet itself is producing far more heat than the earth does.

F.W. Taylor of the Clarendon Laboratory at Oxford presented these measurements at a Royal Society meeting last week. Venus surface temperature is higher than any other in the solar system, at 480 degC. The generally accepted theory is that sunlight is absorbed at Venus' surface, and re-radiated as infrared. The later is absorbed in the atmosphere, which thus acts as a blanket, keeping the planet hot. It is similar to the way a greenhouse keeps warm.

Pioneer has shown that there is enough carbon dioxide and the tiny proportion of water vapor needed to make the greenhouse effect work -- just. If this is the whole story, the total amount of radiation emitted back into space, after its journey up through the atmospheric blanket must be exactly equal to
that absorbed from sunlight (otherwise the surface temperature would be continuously changing).

But Taylor found that Venus radiates 15 percent more energy than it receives. To keep the surface temperature constant, Venus must be producing this extra heat from within.

All the inner planets, including earth, produce internal heat from radioactive elements within their rocks. But Taylor's observations of Venus would mean that the planet is producing almost 10,000 times more heat than the earth, and it is inconceivable according to present theories of planetary formation, that Venus should have thousands of times more of the radioactive elements than Earth does. At last weeks meeting, Taylor's suggestion met with skepticism - not to say sheer disbelief - from other planetary scientists.

Taylor himself has no explanation for his result. He simply points out that the discrepancy seemed at first to be simply experimental error - but with more precise measurements, it refused to go away. More measurements are needed before astronomers accept the result, and most planetary scientists are obviously expecting - and hoping - that the embarrassing extra heat will disappear on further investigation.

Astronomers now claim that Venus is "within error bounds of thermal equilibrium" and cite the noted astronomer Tomasko as a source...

----------------------------------------
Now consider also what happens as probes descend deep into the atmosphere of Venus towards the surface.

There are two articles from Icarus magazine dated 1982 and 1985, the first by H.E. Revercomb, L.A. Sromovsky, and V.E. Suomi of the Space Science and Engineering Center, Univ. of Wisconsin at Madison, the second by the same three gentlemen along with R.W. Boese of NASA-Ames (Icarus 52, 279-300 and Icarus 61, 521-538). Both of these articles involve the infra-red flux sensors on the Venus probes which landed in Dec. 1978. Three small probes carried net flux radiometers externally, and a larger probe carried an infrared radiometer internally. All of these instruments measured the infrared flux of Venus atmosphere.

In the upper atmosphere, all of these instruments showed infrared fluxes which were within expectations; as they descended, however, all began to show very large net fluxes upwards. "Below the Venus cloud deck both LIR and SNFR flux measurements appear to affected by serious errors..." the authors said. "...Although the LIR [large probe enclosed instrument] measurements might be correctable, using the multispectral information of the data to deduce the magnitude of the asymmetry, no reliable corrections have yet been obtained... Thus we cannot at this time make use of the LIR results..."

However, if the scientists lacked imagination in forcing the large probe data into a suitable uniformitarian, Saganesque mold, no such lack occurred with the data from the probes carried on the three small probes: "The magnitudes of the corrections for both instruments are determined by forcing agreement with a range of calculated net fluxes at one altitude deep in the atmosphere, where the net flux must be small because of the large density of CO2...."

"Must be small" is based on the uniformitarianism and "Super-Greenhouse" hypotheses. The idea that four separate instruments of two different sorts, three carried externally and one internally all telling the same story MIGHT possibly just be correct does not even appear to occur to the scientists.

Supposedly, Venus is "within error bounds of" thermal equilibrium in its upper atmosphere, and so these lower atmosphere figures cannot possibly be right, can they?

-------------------------------------------------------------
Astronomers cite Tomasko's article on pages 611 - 612 of the definitive book on Venus, "Venus", by Hunten, Colin, Donahue, Moroz, publ. Univ. of Arizona Press, 1983). This is a monstrous size and costs $80: difficult for ordinary people to gain access. Strangely, there are two articles about thermal equilibrium, the Tomasko article on pages 611-612, AND an article by F.W. Taylor on page 658. It turns out that only by adopting the most myopic view possible can you get thermal equilibrium from the evidence, and that is what Tomasko does.

For thermal equilibrium to pertain, two numbers must match up; the first is emissions which all parties involved agree reads correctly as 0.76. The second number is the planetary albedo. Tomasko claims (pp 611-612) "For the whole planet to be in equilibrium with absorbed sunlight, the bolometric albedo would have to be 0.76..." But the Pioneer Venus readings on albedo (Taylor's article, page 658) was 0.80 plus/minus 0.02, and the calculations from Venera data (also page 658) are 0.79, plus 0.02, minus 0.01. The closest you could get and stay within error bounds is 0.78.

Now you might ask, what's a lousy 0.02 amongst friends; doesn't sound like much... This is one of those cases in which a little bit appears to go a long way. Consider what Taylor claims would have to be believed if the 0.80 figure for albedo were to hold good (also page 658): "Clearly, the Pioneer measurements of emission and reflection are not consistent with each other if radiative balance applies. A source inside Venus equal in magnitude to 20% of the solar input (i.e. accounting for the difference between 0.76 and 0.80) is very unlikely since Venus is thought to have an Earth-like makeup which would imply heat sources several orders of magnitude less than this. Also, even if such sources were postulated, it is difficult to construct a model in which these fairly large amounts of heat can be transported from the core to the atmosphere via a rocky crust without the later becoming sufficiently plastic to collapse the observed surface relief. This could only be avoided if the transport were very localized, i.e., via a relatively small number of giant volcanoes. Although large, fresh-looking volcanoes do appear to exist on Venus (see chapter 6), and the content of the atmosphere is consistent with vigorous output from these, a simple comparison with terrestrial volcanism shows that the volcanic activity on Venus would have to be on an awesome scale to account for the missing 10^15 W or so of power."

That "awesome" volcanic activity is more or less what Magellan [Venus probe] tells us. Taylor does not particularly want to believe what the data is telling him: that there is no way that Venus is within error bounds of thermal equilibrium, but he does not deny the data. How then does Tomasko make a claim of equilibrium? Tomasko cites one 1968 calculation of albedo of 0.77 +- 0.07 without bothering to tell you that that estimate was later revised upwards to 0.80 +- 0.07 in 1975 (Taylor tells us that on page 657), and notes that Taylor's indication of 0.02 error bounds for the Pioneer reading (the most recent, and done with the best instruments from the best distance) may be "too small".

Taylor [Tomasko? error here? I cannot check!] notes (page 758): "A more acceptable alternative is that the preliminary estimate of 0.80 +- .02 for the albedo from the PV measurements is too high, since the uncertainty limit is now known from further work to be too conservative (J. V. Martinchik, personal communication). A fuller analysis of PV albedo data - still the best in terms of wave length, spatial and phase coverage, and radiometric precision, which is likely to be obtained for the forseeable future, is likely to resolve this puzzle. In conclusion then, the best thermal measurements of Venus, with the assumption of global energy balance, yield a value of the albedo of 0.76 +- .01; this is the most probable value."

Tomasko is basing his entire case on one outdated calculation, and upon a "personal communication from Martinchik". Taylor is saying that the best measurements available tell us that thermal balance is not to be had on Venus, and that Sagan and his super greenhouse theory are FUBAR, but that that can't really be, that he and others are probably, hopefully looking at something the wrong way, but he doesn't know what that something is.

That's a long way from claiming that Venus is "within error bounds" of equilibrium.

[Aardwolf]

The Tomasko, M. G., et al. (1980) abstract states (my highlight);

Instruments flown on the Pioneer Venus orbiter and probes measured many of the properties of the atmosphere of Venus which control its thermal balance and support its high surface temperature. Estimates based on orbiter measurements place the effective radiating temperature of Venus at 228 ± 5 K, corresponding to an emission of 153 ± 13 W/m², and the bolometric Bond albedo at 0.80 ± 0.02, corresponding to a solar energy absorption of 132 ± 13 W/m². Uncertainties in these preliminary values are too large to interpret the flux difference as a true energy imbalance. A mode of submicron particles is suggested as an important source of thermal opacity near the cloud tops to explain the orbiter and probe thermal flux measurements. Comparison of the measured solar flux profile with thermal fluxes computed from the measured temperature structure and composition shows that the greenhouse mechanism explains essentially all of the 500 K difference between the surface and radiating temperatures of Venus. Precise comparison of the observed and computed value of this difference is hindered by uncertainties in the local variability of H2O and in the thermal opacity of CO2 and H2O at high temperature and pressure. The directly measured thermal flux profiles at the small probe sites are surprisingly large and variable in the lower atmosphere. Observed zonal and meridional circulation are qualitatively as required to produce the observed uniformity of temperature structure. However, the present lack of quantitative estimates of the horizontal and vertical dynamical heat transports implied by these measurements is a significant gap in the understanding of the thermal balance of the atmosphere of Venus.

It's clear here from the measurements that it has higher emissions so I'm not sure why its disputed.

[Lucy Skywalker]

Aardwolf, thank you so much for that very relevant quote.

However, re your words

It's clear here from the measurements that it has higher emissions so I'm not sure why its disputed..

just look at Tomasko's words directly following your highlight:

Uncertainties in these preliminary values are too large to interpret the flux difference as a true energy imbalance. A mode of submicron particles is suggested as an important source of thermal opacity near the cloud tops to explain the orbiter and probe thermal flux measurements. Comparison of the measured solar flux profile with thermal fluxes computed from the measured temperature structure and composition shows that the greenhouse mechanism explains essentially all of the 500 K difference between the surface and radiating temperatures of Venus... etc

Then he's talking about lower down in the atmosphere, closer to the active volcanoes,

The directly measured thermal flux profiles at the small probe sites are surprisingly large and variable in the lower atmosphere.

But is he sliding unobserved into the upper atmosphere when he then says tellingly

Observed zonal and meridional circulation are qualitatively as required to produce the observed uniformity of temperature structure.

which suggests that measurements from the upper atmosphere only vary within a small range and should therefore easily reinforce each other's accuracy.

It seems Tomasko ends with a fudge-it CYA blah-blah

However, the present lack of quantitative estimates of the horizontal and vertical dynamical heat transports implied by these measurements is a significant gap in the understanding of the thermal balance of the atmosphere of Venus.

all of which bears out what I said about BOTH sides being able to claim OPPOSITE results. The Devil is in the detail.

FYI, here's another interesting detail. I calculated Venus' incoming energy from Earth figures and Venus' albedo and distance from the sun (0.723 AU). Earth TSI =~1366 W/m^2. Divide by 4 to get average insolation =341.5 W/m^2. This accords closely enough with the IPCC figure used on Trenberth's diagram of Earth's radiative energy budget. Now by the Inverse Square law, multiply that by 1/(0.723)^2 and we get 653 W/m^2 at the upper surface of Venus. IIRC, since albedo= 80%, that means only 20% penetrates which yields the figure of 130.7 W/m^2 which interestingly is 2 W/m^2 lower than Tomasko gives. So the discrepancy enlarges slightly.

[allynh]

Note: This post is in three parts because of the limits of the Forum for the number of images you can post at one time.

In the article:

Venus isn't our twin!
http://www.holoscience.com/news.php?article=9aqt6cz5

Astronomers minimized the importance of Velikovsky's remarkable claim or simply dismissed it as a 'lucky guess', although one noted scholar acknowledged at the time that Velikovsky had a remarkable record of successful predictions and no failures. The discovery that Venus was almost red hot made it imperative for scientists to invent an explanation. The result was the "enhanced" or "runaway" greenhouse effect. Rupert Wildt originally proposed the greenhouse theory more than 60 years ago. He predicted that Venus would be warmer than the Earth by a few tens of degrees Celsius due to the trapping of infrared radiation in the planet's lower atmosphere. After the Venera and Mariner probes to Venus showed how unearthly are the temperatures there, Carl Sagan proposed the "enhanced greenhouse effect" in 1960. This was followed by a "runaway greenhouse effect" postulated by S. I. Rasool and C. de Bergh in 1970. According to James Pollack, for the enhanced greenhouse effect to work, a vital 0.1 per cent water vapour as well as 0.02 per cent sulphur dioxide and some unspecified heat absorbing particles in the clouds are required in addition to 96 per cent carbon dioxide in the Venusian atmosphere.

In Google books, if you search on the string:

"Rupert Wildt" +"greenhouse theory"

http://www.google.com/search?q=%22Ruper ... %3A1&tbo=1

You get four books listed, three of them Velikovsky based and one a 2004 science book.

Physics and chemistry of the solar system - Page 525

http://books.google.com/books?id=zm3ChH ... CC0Q6AEwAQ

What is interesting to me is that even in this 2004 edition they still have to slam Velikovsky. I've captured some columns to show the mindset even today.

[allynh]

Edgar Rice Burroughs wrote a fun series set on Venus, based on the information of the day. Venus was a water world. Great fun.

Venus series
http://en.wikipedia.org/wiki/Venus_series

When looking for sources of "what was known", you have to look at what was published before 1940. You can't base anything on modern books, they are all retroactively rewriting the facts to avoid proving Velikovsky true as was shown in the 2004 book above.

I went to "advanced search" on Google books and limited the search to the years 1900 to 1940 on the search terms venus +temperature and found this great link from 1901.

The Astrophysical journal, Volume 14 By American Astronomical Society, University of Chicago
http://books.google.com/books?id=CH8OAA ... re&f=false

This book is available as pdf download.

Then there is a fragment from the 1940 edition:

The Astrophysical journal, Volume 91
http://books.google.com/books?id=b38OAA ... CDQQ6AEwAg

This looks like they thought Venus was 366 degrees Kelvin, which is about 93 degrees Celsius, or about 168 degrees Fahrenheit (Check my conversion, I've been having problems with Math lately. LOL)

Kelvin
http://en.wikipedia.org/wiki/Kelvin

Then I saw the link to:

Popular astronomy, Volume 16; Volume 1908 By Carleton College. Goodsell Observatory
http://books.google.com/books?id=XZ8RAA ... re&f=false

Go ahead and download the pdf as well.

Take your time and see if you can find more pre 1940 books that show the "common knowledge" of the day. I've got to read what I've harvested, and go searching for more. This is fun.

[allynh]

We can chase after science articles and books but that won't convince those following the dogma of the Global Warming Religion. Look at the Wiki pages, especially the quote from "Greenhouse effect".

Runaway greenhouse effect
http://en.wikipedia.org/wiki/Runaway_greenhouse_effect

Greenhouse effect
http://en.wikipedia.org/wiki/Greenhouse ... reenhouses

Real greenhouses

The "greenhouse effect" is named by analogy to greenhouses. The greenhouse effect and a real greenhouse are similar in that they both limit the rate of thermal energy flowing out of the system, but the mechanisms by which heat is retained are different.[25] A greenhouse works primarily by preventing absorbed heat from leaving the structure through convection, i.e. sensible heat transport. The greenhouse effect heats the earth because greenhouse gases absorb outgoing radiative energy and re-emit some of it back towards earth.

A greenhouse is built of any material that passes sunlight, usually glass, or plastic. It mainly heats up because the Sun warms the ground inside, which then warms the air in the greenhouse. The air continues to heat because it is confined within the greenhouse, unlike the environment outside the greenhouse where warm air near the surface rises and mixes with cooler air aloft. This can be demonstrated by opening a small window near the roof of a greenhouse: the temperature will drop considerably. It has also been demonstrated experimentally (R. W. Wood, 1909) that a "greenhouse" with a cover of rock salt (which is transparent to infra red) heats up an enclosure similarly to one with a glass cover.[26] Thus greenhouses work primarily by preventing convective cooling.[27][28]

In the greenhouse effect, rather than retaining (sensible) heat by physically preventing movement of the air, greenhouse gases act to warm the Earth by re-radiating some of the energy back towards the surface. This process may exist in real greenhouses, but is comparatively unimportant there.

Everybody misses the main point about the concept of a "runaway greenhouse effect" on Venus; they need to think in terms of a practical experiment.

- Build a greenhouse, with only Venus level light and see how hot it actually gets.

If anybody can get the temperature up to 800 degrees then they have solved the energy crisis because we can run steam off an 800 degree source. I'm not holding my breath.

In other words, people arguing for the "runaway greenhouse effect" have never actually built a greenhouse.

[Aardwolf]

Aardwolf, thank you so much for that very relevant quote.

However, re your words

It's clear here from the measurements that it has higher emissions so I'm not sure why its disputed..

just look at Tomasko's words directly following your highlight:

Uncertainties in these preliminary values are too large to interpret the flux difference as a true energy imbalance. A mode of submicron particles is suggested as an important source of thermal opacity near the cloud tops to explain the orbiter and probe thermal flux measurements. Comparison of the measured solar flux profile with thermal fluxes computed from the measured temperature structure and composition shows that the greenhouse mechanism explains essentially all of the 500 K difference between the surface and radiating temperatures of Venus... etc

Then he's talking about lower down in the atmosphere, closer to the active volcanoes,

The directly measured thermal flux profiles at the small probe sites are surprisingly large and variable in the lower atmosphere.

But is he sliding unobserved into the upper atmosphere when he then says tellingly

Observed zonal and meridional circulation are qualitatively as required to produce the observed uniformity of temperature structure.

which suggests that measurements from the upper atmosphere only vary within a small range and should therefore easily reinforce each other's accuracy.

It seems Tomasko ends with a fudge-it CYA blah-blah

However, the present lack of quantitative estimates of the horizontal and vertical dynamical heat transports implied by these measurements is a significant gap in the understanding of the thermal balance of the atmosphere of Venus.

all of which bears out what I said about BOTH sides being able to claim OPPOSITE results. The Devil is in the detail.

FYI, here's another interesting detail. I calculated Venus' incoming energy from Earth figures and Venus' albedo and distance from the sun (0.723 AU). Earth TSI =~1366 W/m^2. Divide by 4 to get average insolation =341.5 W/m^2. This accords closely enough with the IPCC figure used on Trenberth's diagram of Earth's radiative energy budget. Now by the Inverse Square law, multiply that by 1/(0.723)^2 and we get 653 W/m^2 at the upper surface of Venus. IIRC, since albedo= 80%, that means only 20% penetrates which yields the figure of 130.7 W/m^2 which interestingly is 2 W/m^2 lower than Tomasko gives. So the discrepancy enlarges slightly.

If the absorption was found to be greater than the emission then no-one would have cared about the details because it would have agreed to their theories. The only reason there is controversy is because they now have to explain why their theory isnt wrong and keep it in tact. Evidence of this kind of theoretical gymnastics is found in most sciences, which is why I always try to focus on the facts or actual measurements rather than their filtered interpretations.

[Lucy Skywalker]

Aardwolf, actually I agree with you. I was responding to your words

I'm not sure why its disputed..