I'm not sure it is possible to make any comparison. Earth and Venusian atmospheres are so very different. One major difference is the near absence of water on Venus. If the radiation spectrum of the sunlight is identical to that hitting the earth then large spreads of radiation, absorbed by water on Earth would heat the surface and atmosphere on Venus, no matter how the CO2 absorption bands spread.

EM, as temperatures have not done anything that they haven't done before, your hypothesis is wrong.

Ignoring history etc and fiddling with science and statistics simply proves it. Not that you would accept anything that proves you wrong. Carry on if you must, but don't expect anybody else to pay for it. That is what the political elite are now realising, so my views are as irrelevant as yours.

Please save the good bits of climate science, or else they will get thrown away as well.

Radical Rodent

Whoops! I took the 5th root in the SB calculation. Thanks for the correction. :-)

The calculation you quoted highlighted the problem with your hypothesis. It only gives sensible results if you ignore albedo.

Let me remind you about albedo.

Albedo is the fraction of solar energy (shortwave radiation) reflected from the Earth back into space. It is a measure of the reflectivity of the earth's surface.

For Venus the reflected light comes off the top of the clouds. In a telescope Venus appears very bright because it reflects 70% of the light and therefore 70% of the energy falling on it.

That reflected energy is lost to space. It does not interact with the atmosphere and does not warm the atmosphere. The calculation you quote, and which I muffed, assumes that all the insolation warms the atmosphere. This is an elementary error of physics.

The apparantly match with the 66C temperature is a coincidence based on the misplaced assumption that the atmosphere of Venus absorbs 3.3 times more energy than it actually does.

Radical Rodent

I hate computers.

Let's try that again.

Radical Rodent

Whoops! I took the 5th root in the SB calculation. Thanks for the correction. :-)

The calculation you quoted highlighted the problem with your hypothesis. It only gives sensible results if you ignore albedo.

Let me remind you about albedo.

Albedo is the fraction of solar energy (shortwave radiation) reflected from the Earth back into space. It is a measure of the reflectivity of the earth's surface.

For Venus the reflected light comes off the top of the clouds. In a telescope Venus appears very bright because it reflects 70% of the light and therefore 70% of the energy falling on it.

That reflected energy is lost to space. It does not interact with the atmosphere and does not warm the atmosphere. The calculation you quote, and which I muffed, assumes that all the insolation warms the atmosphere. This is an elementary error of physics.

The apparantly match with the 66C temperature is a coincidence based on the misplaced assumption that the atmosphere of Venus absorbs 3.3 times more energy than it actually does.

ACK

Agreed. With CO2 the dominant greenhouse gas and no water the two planets would respond differently. The climate sensitivity would probably be lower.

ACK

There would also be less band spreading.

Here's the detailed investigation of the effect of albedo from the No-Venusian-Greenhouse advocate Harry Huffman cited:

This analysis is so easy, the result so immediately amazing, and the interpretation just above so obvious to me, yet the opposition to accepting it so universal and so determined, that I was led to unconsciously accept, partially but nevertheless wrongly, the premise of incompetent critics, that my findings were invalid because I had not "corrected for albedo", or in other words had wrongly assumed the Earth and Venus atmospheres were blackbodies, absorbing all the radiation incident upon them. I inadvertently got caught up, over time, in claiming the Earth-plus-atmosphere system behaves like a blackbody. Although this has thoroughly hindered the acceptance of my analysis, my initial approach to the problem was in fact sound (even if too simple-minded for most), and my above, initial interpretation is quite correct, and in fact unavoidable, although it is not a complete statement. The complete interpretation, which I have stressed (as a logical fact) ever since, both in comments below this article, and on other internet sites, is that the two atmospheres must DIRECTLY absorb the SAME FRACTION of the incident solar radiation. For, supposing that both atmospheres do so absorb, and are solely warmed by, the same fraction (f), and given that the ratio of the two planets' distances from the Sun--Venus/Earth--is (A), the governing formula becomes, for the Earth and Venus atmospheres in turn

This result is independent of the fraction f absorbed, which is why naively approaching the problem as if f = 1 nevertheless gives, without the need to even consciously consider albedo beforehand, the amazingly clear result that the temperature ratio depends only--and amazingly, quite precisely--upon the ratio of the two planets' distances from the Sun. Any "expert", upon seeing this amazing result, should quickly have realized it means both atmospheres must absorb the same fraction of the incident solar radiation, and be warmed only by that fraction. So I apologize for not presenting the explicit equations above sooner, for it would have saved me stumbling into error later, and embarrassing my few defenders, in my "blackbody" defense of the original analysis--but I insist my critics have all been more incompetent than I in this matter, in refusing to even consider my correct interpretation, because of what they merely assumed was a fatal error. There was no physical error in my original analysis, because the temperature ratio I obtained was an empirical fact, and the absorbed power ratio I implied from that was a logical fact (simply stated, Venus's atmosphere DOES absorb 1.91 times the power that Earth's atmosphere does, as their temperature ratio shows--and that ratio is precisely that predicted simply from the ratio of their distances from the Sun). Since the two atmospheres DO, factually, absorb the same fraction of the solar radiation incident upon them, there was, in reality, no physical reason to extend the analysis by "correcting for albedo"

Shorter Harry: correcting for albedo torpedoes my theory therefore both planets must have the same albedo because my theory is correct because I say it is.

Not sure what this is, but science it is not.

Radical Rodent

Regrettably you cannot count the same energy twice. It can warm the planet or it can be reflected into space. It cannot do both.

Suppose you start with £1000. You give away £700. You then have £300 left

Your claim is equivalent to saying you start with £1000. You give away £700. You then have £1000 left.

EM 2:22 ,

Whereas in Climate Science, billions have been taken, and there is nothing left to show for it.

Have you thought about doing calculations based on your energy in/energy out, but on money spent/benefit gained?

There is no point wasting more on climate science if money should be spent on sea walls for Bangladesh. The World Archipelago constructed off Dubai has suffered all sorts of financial and engineering problems, but rising sea level has not been one of them.

EM. I don't think you appreaciate what the near absence of water (also oxygen and ozone) would do. If you compare the irradiance spectrum reaching the Earth with that which reaches the surface you find whole swaths of high intensity radiation flux removed. On Venus this wouldn't happen.

RR - Once again, Huffman's analysis is seriously flawed. The pressure range at which his ratio holds corresponds to a narrow altitude range, around 45-60km. As the graph in the Mike Hammer post at JoNova shows, outside this band the correlation breaks down massively.

This range also corresponds to the Venusian cloud layer, the cloud tops reflect c70% of incoming radiation, and the difference between that and Earth albedo effectively cancel out the 1.91 incident radiation so - in this band -the net radiation is about the same as on Earth, which demolishes his calculation and conclusion.

All he is really doing is comparing the adiabatic lapse rates and finding them similar, no great surprise there.

And when this is pointed out, his amazingly verbose response can be accurately summarised as 'I'm right because I'm right'

it is plausible to be skeptical of a number of issues regarding the findings of  IPCC WG1.  However, whether atmospheric gases such as CO2 (and H20, CH4, and others) warm the planet is not an issue where skepticism is plausible.

Dr Judith Curry

it is plausible to be skeptical of a number of issues regarding the findings of  IPCC WG1.  However, whether atmospheric gases such as CO2 (and H20, CH4, and others) warm the planet is not an issue where skepticism is plausible.

Dr Judith Curry

Oct 5, 2016 at 3:59 PM | Phil Clarke

Phil Clarke, how MUCH gases warm the planet IS an issue where skepticism is entirely correct. It is where Climate Science is entrenched in being wrong, and remains in DENIAL.

One myth at a time .....

Our warming is minor and beneficial; our greening is major and miraculous.

So much for the alarmist myth.
===========

Phil Clarke 4:41 if you are bored with the myth of man made global warming, take up Unicorn fart hunting, it is a lot cheaper for everyone else, and could power the whole world (with a climate science 97% level of confidence)

Sorry, I've been busy today and have just been catching up with the discussion about Venus, since I posed my question. Regrettably I'll be absent again for a few days now, but will come back to it next week. In the meantime, thanks to all for an interesting, though a bit confusing (for me), discussion :-)

Martin A

Albedo is longwave radiation, visible wavelengths, which bounce off the planet back into space without affecting it.

Outward longwave radiation is energy which has been absorbed by the surface and atmosphere, heating it, and is then reradiated into space.

On Venus 70% is reflected, 30% is absorbed and then reradiated.. Radical Rodent's hypothesis would only work if 10O% of the insolation were absorbed.

Please reassure me that you do understand the difference between albedo and OLR. I am losing the will to live trying to explain all this to Radical Rodent.

Goodnight

"Entropic Man" and Phil Clarke have no idea how to do good science. For example, the former states that insolation at Venus is twice that at Earth, when in fact the mean value is 1.91, not 2. He then states that the fourth root of 2 is 1.03, but in reality that would be 1.189, and using the actual 1.91, the Venus/Earth insolation ratio is really 1.176. Entropic Man compounds his errors by then calculating that the "Venus equivalent" to Earth's 1 bar temperature of 288K, with no greenhouse effect at work, would be 1.03x288K = 297K, when in reality it would be 1.176x288K = 339K = 66C (which, contrary to his claim above, is just what Venus's temperature is at the 1 bar pressure level--needless to say, the correct calculation was featured in my original 2010 post, but critics like these refuse to acknowledge it. (Radical Rodent reproduced this result, from my original November 2010 post just above, yet of course Entropic Man and Phil Clarke just ignore the fact, and even claim otherwise, ludicrously so to anyone capable of doing the simple math themselves, and verifying my analysis).

Phil Clarke claims the Venus and Earth profiles are only "similar" between 50km and 60km altitude (on Venus) and, he says (or quotes someone else) "and quite different at other altitudes"; but that is a misleading claim, since I specifically compared the Venus profile with Earth's Standard Atmosphere model for the troposphere, and ONLY for the troposphere region, whose pressure range (1,000mb down to 200mb, from ground level to 11km on Earth) indeed is found in (approximately) the 50km to 60km altitude range on Venus; the point is, that is the FULL RANGE of Earth tropospheric pressures, and only over that range does the hydrostatic condition, and the consequent constant negative lapse rate in temperature, hold in Earth's atmosphere--it is the only range with a clear (and simple) physical explanation behind it (and surprise, surprise, it fits the Venus data over that range, very well). As my original "Venus: No Greenhouse Effect" post made clear, and I quote:

"The radiating temperature of Venus should be 1.176 times that of the Earth. Without ANY greenhouse effect as promulgated by the IPCC, [and given the hydrostatic condition,] at any given pressure within the range of the Earth atmosphere [that is, the Earth troposphere, as I have always emphasized], the temperature of the Venus atmosphere should be 1.176 times that of the corresponding Earth atmosphere. ...[a table follows, giving Earth and Venus temperatures over the full range of Earth tropospheric pressures, 1,000mb down to 200mb]...(with the result that) The actual ratio overall is 1.165 +/- 0.015 = 0.991 x 1.176. It does not vary from the no-greenhouse theoretical value at any point by more than about 2%." That maximum 2% variation from 1.176 only amounts to about 5K in temperature, and it only occurs within the thick planet-wide cloud cover of Venus; below the clouds, the ratio is right at 1.176, while above the clouds, the ratio comes back up to within just 0.7% of 1.176. As I have written many times in the 6 years since the original post, the marginally smaller ratio within, and only within, the clouds of Venus is most likely due to a larger specific heat in that region, due to the non-gaseous particles in the clouds.

As Radical Rodent tried to point out above, the greenhouse effect, as promulgated by climate scientists, is an ADDITIVE effect, amounting to from +11C (for a CO2 "sensitivity" of 1C/doubling) to +33C (for the IPCC's claimed 3C/doubling), after the difference in insolation is taken into account. I presented a graph comparing the T-P profiles of Earth and Venus (again, for 1,000mb down to 200mb), and there is not the slightest hint of any such additive warming of Venus's atmosphere above that for Earth, due to such a "greenhouse effect". "Entropic Man" and Phil Clarke of course ignore that clear graph. Only the difference in solar distance is needed to explain the precise Venus/Earth temperature ratio, above and below the Venus cloud region.

And it is the PRECISION with which the Venus temperatures, over that full range of Earth tropospheric pressures, are calculated (taking only the different solar insolation into account), that allows any competent physical scientist to state with assurance that there is no further effect upon the global mean temperature, at any level in Earth's troposphere: No CO2 "greenhouse effect"; no "difference in albedo" effect; no "difference in planetary surface" effect; no "difference in internal planetary heat" effect; no "difference in planetary rotation rate" effect; no "clouds" effect -- nothing but the solar distances are needed (plus, a small effect within the clouds of Venus, which I claim is most likely due to a higher specific heat there). All of those other effects, some multiplicative and at least one (the "greenhouse effect") additive, would have to precisely cancel one another out, AT EACH AND EVERY PRESSURE LEVEL IN THE TROPOSPHERE, so that all of them together had precisely ZERO effect, in order to uphold consensus climate theory. There are so many of them, and they are all of such large effect, that getting them all to cancel, so precisely, is impossible. Any really competent physical scientist should see that right away, upon seeing my analysis, and its clear graph. Unfortunately for the layperson, the "global warming" promulgators are, to a man, incompetent (which really means, deluded by their false dogma, which they refuse to have questioned, much less refuted), refusing to acknowledge definitive evidence that disproves their theories.

One cannot easily "take account of the difference in albedo" anyway, as the most common denial of my Venus/Earth comparison demands, since no one knows how much of the reflected radiation would actually contribute to the warming of the atmosphere. My Venus/Earth analysis indicates, in fact, that NONE of the radiation reflected by either Venus or Earth, from either clouds or the planetary surface, would otherwise go into warming, or (more correctly) maintaining the fixed warmth of, the atmosphere. The complete absence, in the observed Venus/Earth temperature ratio I presented, of all those supposed effects mentioned above, means that the troposphere must be maintained, in its stable Standard Atmosphere state, by direct absorption of incident solar radiation, not at all by heat from the surface (which, in addition to spreading out around the globe, and producing transient and local effects like the winds and weather, merely escapes vertically to outer space, "down" the temperature gradient, without further heating the atmosphere (in other words, the temperature lapse rate structure, due to the hydrostatic condition, predominates over all other processes in the atmosphere, providing a stable global mean temperature; the climate "experts" are stuck with bad theories about subordinate, non-global effects only). It should come as no surprise that the wavelengths of solar radiation that are directly absorbed by air molecules are quite apparently not at all the same as the wavelengths that are reflected by non-gaseous clouds or planetary surface (and which thus account for the albedo).

I have written all these things and more many, many times over the last 6 years. Believers in the consensus climate science refuse to honestly confront, and (unavoidably, sooner or later) accept, them. Think of all the careers, all the lifetimes of misdirected work in the accepted "climate science', are at stake. Yet their scientific incompetence is glaringly obvious, from my Venus/Earth comparison alone.

Don't bother trying to respond, critics, including Entropic Man and Phil Clarke. Your "science' is beneath contempt, and I post this only to inform others who happen by.