RealClimate is run by a rather loosely organized volunteer consortium of people with day jobs that in and of themselves can be quite consuming of attention. And so it came to pass that the first I learned about Gavin’s interest in the work of Plass was — by reading RealClimate! In fact, David Archer and I have a book due to appear this year from Wiley/Blackwell (The Warming Papers), which is a collection of historic papers on global warming, together with interpretive essays by David and myself. Needless to say, we pay a lot of attention to the seminal work by Plass in this book. His 1956 QJRMS technical paper on radiative transfer, which is largely the basis of his more popular writings on global warming, was one of the papers we chose to reprint in our collection. In reading historic papers, it is easy to fall into the trap of assuming that investigators of the past are working on the basis of the same underlying set of assumptions in common use today. Through a very close reading of the paper, David and I noticed something about the way Plass estimated surface temperature increase, that Gavin and all previous commentators on Plass — including Kaplan himself — seem to have overlooked.
These days, it is fairly common knowledge that determination of surface temperature change requires simultaneous satisfaction of the top-of-atmosphere energy budget and surface energy budget, and that in most circumstances it is the top-of-atmosphere budget that plays by far the leading role. This is one of the many things that Arrhenius got spot-on right in his conceptual framework for computing surface temperature. His computation explicitly takes both balance requirements into account, though substantial inaccuracies were introduced because the onerous computations involved in solving the model pretty much restricted him to a one-layer representation of the atmosphere. Later workers improved on Arrhenius by introducing multiple layers and more accurate spectroscopy, but did not always note the importance of satisfying the top-of-atmosphere balance. I think it seems natural to most people to assume that if one is interested in surface temperature, the surface budget must be the most important thing to look at. Plass, for all his brilliance in computing the radiative effects of CO2, was one of the ones who was led astray by this fallacy.
Since discussions of radiative forcing today are almost invariably based on top-of-atmosphere budgets (or at least top-of- troposphere budgets, which are almost the same thing), it is natural for the modern reader to assume that when a paper quotes a radiative forcing, it must be a top-of-atmosphere forcing. This is what Gavin assumed, but a close reading of the 1956 QJRMS paper shows that this is not, in fact, what Plass was talking about. In that paper, Plass does not get around to turning his voluminous radiative calculations into a surface temperature change until nearly the last page of the paper, and when he does, he spends barely a page explaining the reasoning.
The radiative forcing Plass quotes is actually the increase in downward infrared radiation to the surface, which you get if you double CO2 while holding the atmospheric temperature fixed . This back-radiation increases because increasing the concentration of a greenhouse gas makes the atmosphere a more efficient emitter of infrared radiation, at least up to the point where the lowest bits of the atmosphere emit so well that they essentially have become a blackbody, whereafter the emission to the ground can no longer increase unless the air temperature changes. For Earthlike conditions, the emission from CO2 is nowhere near saturated in this sense (see this post ) , so Plass was entirely correct in inferring an increase in the back-radiation, at least for a relatively dry atmosphere. Adding CO2 to the atmosphere is a bit like turning up the dial on a heat lamp you are lying underneath.
It is in the final stages of the calculation that Plass went wrong. He assumed that the surface would get rid of the extra infrared radiation it was receiving by heating up until it was able to radiate away the excess. This reasoning ignores the fact that radiation is not the only means of exchanging heat between the atmosphere and the surface. There are also turbulent exchanges, including evaporation, and these would tend to limit the surface warming to values far less than the values Plass estimated. Further, when the lower atmosphere is warm and moist, such as in the tropics, the great infrared opacity of the large quantity of water vapor tends to limit the direct effect of CO2 on back-radiation into the surface, which further limits the surface warming if the air temperature is held fixed as Plass did. To be fair, Plass does include a sentence implying that he was concerned about the portion of the retained flux that exited through the top of the atmosphere, but even if one gives the most generous interpretation to what might have been meant by this statement, there is no way to make a consistent calculation out of it, given the use of the surface back-radiation as radiative forcing.
The way the greenhouse effect really works is that adding CO2 reduces the infrared out the top of the atmosphere, which means the planet receives more solar energy than it is getting rid of as infrared out the top. The only way to bring the system back into balance is for the whole troposphere to warm up. It is the corresponding warming of the low level air that drags the surface temperature along with it — an effect left entirely out of Plass’ calculation.
A more quantitative discussion of the way all this works can be found in The Warming Papers, and a yet more advanced discussion of such things can be found in Chapter 6 of my book Principles of Planetary Climate (which at long last has been shipped off to Cambridge University press, animula vagula blandula)
In point of fact, Plass did compute the top-of-atmosphere radiative forcing due to doubling or halving the concentration of CO2. The result is plainly shown in the rightmost graph of his Figure 7, where he shows the vertical profile of upward and downward flux for three different CO2 concentrations. Reading the values from the top of the graph, I get that Plass computes a 3.2 Watt per square meter reduction in the outgoing radiation for a doubling of CO2. This is really quite close to the modern value. Plass does not mention this number, or its importance, anywhere in the text, however. Still, it would be fair to give Plass the credit for the first calculation of top-of-atmosphere radiative forcing using correct modern radiative physics. Though he did not make good use of the calculation himself, the methods he introduced are largely the same as those used by Manabe and Wetherald in 1967, who were the first to put together correct spectroscopy with a correct framework for computing surface temperature, adding in accurate water vapor spectroscopy and the effects of convection along the way.
Thus, while Plass made seminal contributions to radiative transfer, his actual estimate of surface temperature increase cannot be regarded as an improvement over Arrhenius. Plass had better spectroscopy than Arrhenius, but a framework that would not give the right answer no matter how good the radiative transfer was. The point of all this historical deconstruction is not to poke fun at Plass or detract from his contributions. Theories do not spring from scientists full-formed like Athena from the head of Zeuss. Science often proceeds through a series of errors and corrections, and those who move the ball forward are in the thick of this process even if they have made some mistakes. The point is that our current understanding of global warming rests on the shoulders of some of the greatest giants of physics of the past century or more, and myriad lesser but still substantial intellects as well.
So, when push comes to shove, was Plass a Hedgehog or a Fox? The answer is: a bit of both. With regard to computing the radiative fluxes due to CO2, Plass was a true hedgehog — he knew that one thing really, really well, and that had a lasting impact on our science. But in his Tellus article, he also showed himself to be quite a fox, in that by knowing (and explaining) many independent lines of thinking, he helped to revive attention to the wide-ranging importance of CO2 in climate. You could say he was not enough of a fox to have also absorbed the lesson of the importance of top-of-atmosphere balance, known already to Arrhenius. But also, you could say that if you’re going to be a hedgehog and pick one thing to be the central organizing principle of your world view, it had better be a pretty darn universally important thing to know. If you’re going to be a climate hedgehog, the constraint imposed by top-of-atmosphere radiation balance would be a pretty good place to hang your hat.
BPL (#126), yes, Canon 1370 should cover it.
:)
128 Hank Roberts,
I did look it up and do indeed understand, I think. Apparently my assumption about subtracting large numbers was wrong. 494-493 does not equal zero. The small difference of 1 (or as I understand now, .9) is actually what we are talking about. And thanks to you and Luke for goading me out of laziness so I actually did the calculation about what this means, as in my last.
But the upshot of my last is that the number of .9 W/m^2 looks like an underestimate. Looking again at the NOAA chart, it looks like .9 would have been a good estimate for the rate from 1955 to 1995. And if extended to now, that would have led to an ocean heat content of about 4×10^23J. But oops, it has gone up a lot faster in the last 20 years. And as Luke and I calculated, the right number should be about 3.1 W/m^2 .
I note in passing that when models work on such small differences, it is difficult to get great accuracy. I guess that is why we have giant computers working on this. But we should still be a little cautious.
I am still looking for more discussion on how the ocean interface is handled, but for now it looks like the power of the ocean-wind interface has been underestimated in the models and the atmospheric temperature increase predictions are therefore a little high. Maybe the sea level increase predictions have been a little low. Ugh and argh!
This seems like a good thread to ask a question, though it may not be a very good question to ask, or at least not very well put.
Background: A skeptical acquaintance has been insisting that the “greenhouse theory” requires the atmosphere to warm “from the outside in”, i. e. more warming aloft than at the surface, because “GHGs trap heat” and any additional heat-trapping will not take place near the surface where it’s already (near) saturated, but up high where additional GHGs make (more of) a difference. Ehm, right. So I explain about convection, the adiabat, back-radiation etc. etc. and eventually work my way up to the top of the atmosphere.
But it left me wondering, are there circumstances, if only as a thought experiment about a different planet or a very crippled model of our own, in which my acquaintance would be right?
PS. For clarity, my outside-in question above was not about enhanced warming aloft due to a shift toward the moist adiabat, as in the tropical troposphere ‘hot spot’ issue — that was not the mechanism envisaged by my acquaintance.
http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/MonteVeritaPaper_ss_rev3.pdf
“… Current global analyses of the atmosphere and the ocean contain spurious variability on decadal time scales that arises from inadequacies and changes in the observing system…. Results for ocean heat content are discussed in the light of recent corrections to ocean soundings and new ocean observations, and in the context of the thermosteric contributions to sea level rise.”
I have added “Principles of Planetary Climate” to my check out and probably buy list. This has been a good thread.
CM (#153):
On Earth at least, the whole troposphere pretty much warms up in concert as it is meshed together by convection. Over much of the globe the tendency is to keep the lapse rate near a moist adiabat and the IR heating pretty much just sets the intercept of the temperature profile. Your correspondent is probably trying to re-phrase the “tropical hotspot” line, whereby the upper tropical atmosphere is expected to be amplified in warming relative to the surface (the situation is opposite near the poles though). This issue generally comes down to model-obs validation and the quality of data in the tropics, and has nothing to do with a unique GHG “fingerprint” that we’re not seeing.
CM says, “A skeptical acquaintance has been insisting that the “greenhouse theory” requires the atmosphere to warm “from the outside in”, i. e. more warming aloft than at the surface, because “GHGs trap heat” and any additional heat-trapping will not take place near the surface where it’s already (near) saturated, but up high where additional GHGs make (more of) a difference.”
Huh?!? This is absurd on its face. More photons will always be trapped where the flux is greatest. Collisional relaxation will also be greatest where densities are highest. What is more, the effect doesn’t saturate even at low altitudes–you will absorb more photons in the wings of the spectral lines. Your acquaintance has no idea what he is talking about.
141 Raypierre: The simple answer is that adding CO2 cools the stratosphere by increasing the infrared cooling, which makes it less stable and allows the tropospheric convection to reach to higher levels. That sounds pretty plausible, but it’s not as inevitable as it sounds, because the stratospheric cooling competes with other effects.
Does not the stratosphere also absorb more energy that has been re-radiated downward from the upper atmosphere? Or, could you elaborate on the other effects?
[Response: The part of the atmosphere above the stratosphere has very little infrared radiative effect, so you can pretty much ignore that. But I wish to emphasize that the factors determining the tropopause height are fairly subtle, and I’m sweeping a lot of issues under the rug when boiling this down to a one liner. Here’s another take on the behavior: When there’s enough CO2 in the stratosphere to overwhelm the effect of heating due to solar absorption by ozone or other solar-absorbing constitutents, the stratosphere reaches an equilibrium between absorption of upwelling infrared and radiative cooling by upward and downward emission of infrared radiation. In the limit where the stratosphere is optically thin in the infrared, the upwelling infrared is little affected by the stratosphere, so the skin temperature is fixed by the OLR, which in equilibrium is equal to absorbed solar radiation. This means the skin temperature remains fixed for a given planet, if you don’t change the albedo. Now, as you add greenhouse gas, you warm the surface, so the air has to rise further along the adiabat before it cools to the skin temperature and loses buoyancy. This solution, with an optically thin stratosphere, is the self-consistent one for common atmosphere-forming gases, though it is mathematically possible for the slope of the adiabat to be such that the stratosphere instead becomes optically thick and the troposphere becomes thin as you add more greenhouse gas. –raypierre]
CM, the closest would be Europa, a moon of Jupiter. The theory is that the cracks and features in the ice that cover it are from the water beneath heating and melting it.
The heat is caused by tidal warping (friction), so it is internally produced.
Here’s how to explain how the lower atmosphere gets hot, even though the solar radiation passes through the higher air to get there:
On a sunny summer day the bottoms of our bare feet burn on the pavement, not the tops. That the snow stays on the top of the mountain even when the folks at the bottom are wearing t-shirts.
The fundamental problem, of course, is the disconnect between actual greenhouses and the greenhouse effect. Greenhouses work in large measure because the air isn’t allowed to circulate freely, so there is no outward radiation and the air convects in a closed environment of the same atmospheric pressure.
The actual atmosphere of the planet goes from very tiny densities to what we think of as normal pressure to where we are. Thicker stays hotter longer.
The atmosphere is transparent to visible light.
Visible light photons hitting the surface (water and land) transfer their energy to it — and the surface warms up. The surface warmth is radiated in the infrared (because “that’s how hot it is”). Greenhouse gases interact with infrared photons, on their way up from the surface.
Argh. It’s nuts to try to retype this FAQ from memory. The Start Here button at the top of the page is a better place to look for these answers.
113 Philip, 127 Barton, 131 Goeff, 66 and 132 Ray
Carbon dioxide has both vibrational (mostly near infrared) and rotational (mid-infrared) energy states that are excited by absorption of photons. The former is important for direct solar radiation, but the latter is the most important in reprocessing the radiation from earth and the atmosphere. The key point, and the essence of the science behind the “greenhnouse effect”, is that the radiative lifetimes of the excited vibrational and rotational states are much less than the collisional times with molecules in the atmosphere. Thus an excited CO2 molecule will undergo many collisions before it has a chance to radiate away its energy, and in the process will transfer kinetic (thermal) energy to the atmosphere This comes out of the quantum mechanical calculations, and represents the essential science behind the “greenhouse effect”. See my former comment #53 above.
Similar to 158, shouldn’t a simple 1 absorption line 1 layer model produce the logarithmic dependency of forcing versus concentration? The simplest way to think of it to to consider the IR spectra to have two regions (1) wavelengths where the optical depth is less than one, and (2) wavelengths where the optical depth is greater than one. If the line shape is exponential, then the “width” of the line (in the sense of the width of set (2) above) varies as the exponent of the concentration. Thats why I get a disconnect whenever I hear the saturation argument.
159, Raypierre
That will take a while to absorb, so to speak.
I looked for your book at CUP, but couldn’t find it, at least not by name. I’ll look back later.
yours truly,
Matthew
Raypierre, what do you think of this book?
Stochastic Physics and Climate Modelling
Edited by Tim Palmer
University of Oxford and European Centre for Medium-Range Weather Forecasts, Reading, UK
Paul Williams
National Centre for Atmospheric Science and University of Reading
John,
Does this help at all?
http://BartonPaulLevenson.com/Saturation.html
Frank: “Here’s how to explain how the lower atmosphere gets hot, even though the solar radiation passes through the higher air to get there:”
I would ask you to figure out the effect since the moon’s pull on us is twice the Sun’s and Europa is close to a much heavier object than our moon.
“The fundamental problem, of course, is the disconnect between actual greenhouses and the greenhouse effect.”
Greenhouse != greenhouse effect.
The Barbra Streisand effect doesn’t turn people trying to silence critics into singers, you know.
“The actual atmosphere of the planet goes from very tiny densities to what we think of as normal pressure to where we are. Thicker stays hotter longer.”
Denser is hotter:
PV=nRT.
Ideal Gas Law. The top of the atmosphere doesn’t have much bearing down on it so has low pressure. The bottom of the atmosphere has the entire weight of the air on it so has high pressure.
And the only way to lose energy into space is to radiate.
E=sT^4
(yes, the PV=nRT is complicated by water phase change dumping potential energy into the air, but where and how quickly is based on the ideal gas law)
CM: “as in the tropical troposphere ‘hot spot’ issue ”
There is no hot spot issue.
1) such a feature is a feature of any cause of global warming therefore its lack is not proof the sun’s doing it or GCRs or…
2) such a feature cannot be discerned with the instruments and calibration of same because the errors in measurement and correlation with each other are far too large for the warm spot to be discerned
Chris Colose, Ray Ladbury, Frank Giger, CFU — thanks.
Chris, sorry I didn’t make this clearer and save you some typing, but I do understand about the troposphere warming as a unit due to convection, though my acquaintance did not. (I think he got his ideas from a dumbed-down explanation of GHGs “trapping heat”, without thinking about where that heat might go after being “trapped”, and combined with misinformation about the lower atmosphere being “saturated”, though he may also have heard something about the “hotspot” that he thought fitted.)
My question was a hypothetical one about whether, on a sufficiently exotic planet or in a sufficiently incomplete model of our own planet (with convection suspended, for starters), there could be conditions where one would see a greater temperature change in higher layers than lower ones as more GHGs are added, and where the difference would somehow have to do with radiative absorption.
I’m not sure from Ray’s reply if this question is absurd on its face, or only my acquaintance’s argument with regard to the Earth we live on, which was certainly a clueless one.
Frank, thanks for trying to help, but I don’t think a tidally heated Europa comes into it, and “thicker stays hotter longer”.
Completely Fed Up, yes, I am aware that the “hot spot” is not a “fingerprint” of greenhouse warming and that measurement errors so far do not let us resolve whether it’s shown up (I’ve read Thorne et al. 2007). I mentioned it only to say that this was probably not what my acquaintance was going on about, and not what I was asking about.
I do understand that there are big holes in my understanding of radiative transfer that I should probably try to fill from a textbook, rather than by wasting you gentlemen’s time asking vague hypothetical questions on this blog.
CM, there’s no way you can avoid convection unless there’s no temperature difference. Since that has to fit in space at about 3K, this would require a surface at 3K too…
So it’s a non-starter, really.
CM, Ray Pierrehumbert does have a piece on ‘Science Fiction Atmospheres’ worth reading: http://geosci.uchicago.edu/~rtp1/papers/BAMS_SFatm.pdf
(He cautions that adding water to Dune could trigger a runaway greenhouse, for example; this geoengineering stuff always has to be thought through.)
“If you have the choice between
a hypothetical situation and
a real one, choose the real one.”
–Joan Baez to Michael Krasny; KQED Radio, 2003/02/04
Correction to 162. The radiative lifetimes of the rotational and vibrational states are much LONGER than the the mean collision time between molecules.
171 Hank Roberts,
There are some real questions to work on and some real possible solutions. Geoengineering stuff is a distraction.
It reminds me of the story of the husband who bragged about how he and his wife shared the decision making process. He was in charge of the world nuclear military power balance and other cold war issues. She was in charge of where they lived, what cars they bought, what they ate, and when they went to bed at night.
Geoengineering is, hopefully, not something that anyone will actually try to do. Acknowledging the reality of the CO2 imbalance, understanding how this will impact our lives, and finding practical solutions are things we might actually be able to do.
Where climate modeling fits in this is a little uncertain. If you see my point in #152, you might think climate modeling is a little off, as it now stands. I say that temperature increases are over-predicted in light of the ocean heat content as shown by NOAA. This really simple discussion seemed important, but then we got off into other matters that most of us don’t seem to understand at all.
Hi Ray,
Nice to read your article.
I agree with you that without taking the energy balance at TOA into consideration, the surface temperature change due to the increase of CO2 will be largely under-estimated if only the radiative energy balance at the surface is used and if the surface turbulent sensible and latent heat fluxes are not considered, because it is well-known the radiative forcing of 2CO2 is about 4 W/m^2 at TOA, but only about 1 W/m^2 at the surface.
However, I wonder even the combined-TOA-surface radiative forcing is still not enough for explaining the surface temperature change. Maybe the continuous vertical structure of radiative forcing from doubling CO2 has to be taken into consideration. I mean the vertical structure of 2CO2 forcing as in Figure 2 of ( http://www.springerlink.com/content/6677gr5lx8421105/ ) with largest radiative heating in the lower troposphere and radiative cooling in the middle troposphere is essential to the surface temperature change.
Suppose a radiative forcing with exactly same values at both TOA ( 4 W/m^2) and the surface ( 1 W/m^2) as that of doubling CO2, but the largest radiative heating is located in the mid or upper troposphere with radiative cooling in the lower troposphere, then the surface temperature change may be totally different to the warming in response to 2CO2, for the change in dynamics ( including the global energy and water cycle) in response to the supposed forcing is different from the one under 2CO2 forcing, though the forcings at TOA and at the surface are same.
174 Jianhua Lu,
How can it be said that 1 W/m^2 “forcing” at the surface due to 2CO2 is well known (Is this 1985-2005 level?) when heat went into the ocean at a rate of 3.1 W/m^2 during this time?
To Jim Bullis, Miastrada Co @ 175:
The ~ 1 W/m^2 is the radiative forcing at surface directly from doubling of CO2, but the heat went into the ocean can be at a a rate of 3.1 W/m^2 due to the net radiative effect at the surface of the changes in water vapor and clouds.
Note the radiative perturbation at surface due to water vapor changes are much larger than that at TOA, according to the Figure 3 in http://www.springerlink.com/content/6677gr5lx8421105/ .
Jim Bullis, judging just from the abstract there, they’re discussing
“contributions from both radiative and non-radiative feedback processes”
(which are different than the forcing). I haven’t seen the whole paper.
But you know the difference between a forcing and a feedback.
I think I answered my own question. The 4 W/m^2 represents the rate of accumulation of all heat from top of atmosphere to center of the earth. So the 3.1 W/m^2 into the ocean comes from that budget. The .9 W/m^2 said to be at the earth surface is not really there at all. It is just the rate of heat going into the space from top of atmosphere to bottom of atmosphere.
If the 10×10^23 Joules had not gone into the ocean over the last 20 years, that would have warmed the atmosphere about 7.5 deg C. As it is the .9 W/m^2 warmed the atmosphere about 2.5 deg C, according to my approximations.
This explanation might only have meaning to others who find the “forcings” terminology hard to translate into ordinary physics terminology.
177 Hank Roberts,
Thanks, but I showed in my last how poorly I understand this terminology.
I guess the heat going into the ocean is a feedback. At least I would have suggested that with an arrow in that direction.
Of course no one cares, but it is also conceptually awkward to say that a forcing occurs at a top of the atmosphere when that is only the place it is calculated. The effect is distributed to all points below. And the forcing at the earth’s surface is distributed from surface to top of atmosphere, and does not include effects going downward. I would say these definitions are badly done; a little late to complain of course.
I had to spend a few hours sorting this out, and I hope I have it now. Thanks to the good spirit of this site, I am willing to put up with this.
To Jim Bullis, Miastrada Co. @178
A good reference for some basic concepts on ” forcings” and “feedbacks” is
S. Boby et al: How Well Do We Understand and Evaluate Climate Change Feedback Processes? J. Climate 2006, Vol 19: 3445-3482.
http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2FJCLI3819.1&ct=1
Thank you Jianhua Lu. Don’t let us nonscientists clog up the thread, I hope we see conversation among the real scientists develop. The Boby paper is more than a long weekend’s reading. And it has been cited more than 100 times. More to read.
http://scholar.google.com/scholar?cites=12071981717443458872&hl=en&as_sdt=2000
Thank you, Hank.
Sorry first for the typo, the first author of the paper I mentioned is S. Bony, not Boby. In the appendix of that paper, the authors give a very concise and clear discussion on the basic concepts, and I think it very helpful for readers interested in climate change science.
For the radiative forcing due to doubling 2CO2, the allocation of the 4 W/m^2 at TOA is (roughly) that about 1W/m^2 at the land and ocean surface and 3 W/m^2 in the troposphere, especially in the lower troposphere.
Thanks 180 Jianhua Lu and 181 Hank Roberts for the Boby reference.
However, that paper confirms that the heat going into the ocean is not a feedback that is considered, as per my original point. And we see why there is no arrow going downward in the diagrams.
Thus, the reference on this present site
https://www.realclimate.org/index.php/archives/2009/12/updates-to-model-data-comparisons/
that shows a large amount of heat going into the oceans, that is, 10×10^23Joules, is showing heat that is ignored. And there is a real reason to show the heat going down from the surface.
All the talk about feedbacks seems to be ignoring a very important feedback.
Re my last,
The Bony paper acknowledges the prior use of the term “feedback” by Bode (1945) but curiously does not seem to notice that the Hansen (1984) usage is not at all consistent with that earlier usage.
CFU, Hank,
My question clearly was a non-starter and I’m not going to pursue it (but I appreciate the replies I got). Just two quick notes on your replies, then I’ll stop clogging up the thread.
Hank #171, Ray P.’s essay on climate science in science fiction (sci-fi cli-sci?) is a gem, thanks for the pointer. (But even on Dune water-poisoning the sandworms was a more immediate problem than the runaway greenhouse…)
Completely Fed Up #170, I understand that it’s hard to avoid convection playing a big role in a real atmosphere. But not because of “any” temperature difference: not where temperature increases with height, as in our dynamically stable stratosphere — which makes the temperature of space irrelevant to convection in our troposphere. Or am I missing something?
In a more exotic vein, Ray Pierrehumbert describes in _Principles of Planetary Climate_ (s. 4.3, pp. 175-6 in the last draft I downloaded) a possible case of a gas or ice giant with an atmosphere optically thick in the infrared, with weak solar absorption, but yet deep enough that all solar radiation is absorbed; its deep atmosphere exhibits a strong greenhouse effect, is hot, and is isothermal, hence stable and will not generate a troposphere.
So on my physics-for-poets level, I just got curious if there might also be a plausible planet with something like the behavior my acquaintance fancied. In any case, it’s clearly not this one.
I am one of those infamous “non-scientist” interested spectators to this discussion, lured in by pure accident, having been curious to know why so many people have been coming to my post of animula blandula, vagula.
Now I understand.
There has been a call for observations concerning current climate trends, but I don’t see that anyone has noticed the development of a significant El Niño event in the Central Pacific, with powerful effects now beginning to be felt on the California coast (where I live). It’s already shaping up as a classic El Niño, the most potent in at least twelve years. I recognize that “scientists” don’t play hunches based on local experiential phenomena, but guess what? Normal humans do. And the news from here is: hey, something’s happening, and the only reason “scientists” haven’t been saying more about is that they didn’t see it coming.
Seems we folk in Australia are about to be visited by Lord Christopher Monckton, (do you Brits really still use such titles??) who has sent an open letter to our prime minister Kevin Rudd claiming that even if the Copenhagen accord is fully implemented over the next decade, the effect on global warming is slight. Moncktons letter includes basic maths in the full version at http://scienceandpublicpolicy.org/originals/open_letter_rudd.html
which has gained approving comment from the usual suspects, but has to be wrong by a couple of orders of magnitude given IPCC predictions. Can we have a rebuttal statement by someone who knows what he is talking about please? (preferably someone with an earned title!).
[Response: Actually, “Lord Monckton” is completely made up as a title. The UK does not use ‘Lord’ in this sense. He is a viscount and although he stood for election to the House of Lords, he got no votes. He is not a ‘lord’ in any sense of the word. Neither is a he a ‘science advisor’, nor a ‘Nobel Laureate’. He is however, as good an argument for the abolition of hereditary peerages as I’ve ever seen. See Deltoid for a discussion of his maths errors. – gavin]
The problem is that that thought experiment was so impossible you might as well say “and magic occurs”.
Maybe a very simple maths idea:
2+5=7
What happens if you change just one thing?
3+5=7
therefore wrong.
But you (and Rod B) want to say “no, but is there a way where you can change just one thing and the equation is still true?”.
The answer is “no”.
Even though Rod wants to say “how about
2+5+0=7
eh?”
But doesn’t realise he’s changed two things:
0 has been added
+ has been added
And, in Rod’s case, he doesn’t see (or doesn’t want to say he sees) it.
CM: “not where temperature increases with height, as in our dynamically stable stratosphere — which makes the temperature of space irrelevant to convection in our troposphere. Or am I missing something?”
Yes, CM: how is the atmosphere that you’re talking about simple? The stratosphere is hotter because of the chemical constituents higher up can absorb visible light and are, therefore also greenhouse gases, just working on a different energy scale.
And there’s still the driver of convection: temperature differences. And the space is cold, so the atmosphere will cool with height. Chemistry and photon absorption make the temperature profile much more detailed, but the gross picture has to be “cools with height” as long as the ground is at a higher temperature than the space it is sitting in.
Or solid, I suppose.
[Response: Actually, “Lord Monckton” is completely made up as a title….gavin]
Although the BBC don’t agree and insist that using that monicker is pretending to be Christopher Monckton.
They also consider “professor monckton” to be him, despite that not being his name, nor his title.
But moderators are hidden on the BBC and unaccountable. And with that lack of accountability comes petty willy-waving and all you need is one of them to consider the above true and you’re canned.
Go figure.
PS that gas giant is really weird.
How do you manage to get weak absorption of Vis, high absorbtion of IR AND thick enough to absorb within the atmosphere all Vis irradiation and yet not so thick that it is too heavy and is, instead, a star?
It would have to be practically all one molecule type, else you have problems with differentials in absorber temperatures at different wavelengths that would break isothermality.
But unless you picked a robust molecule, long before you get to 3 optical depths in some wavelengths, you’d have enough pressure/temperature to break the molecule up.
As a theoretical, it is, I would suppose, possible. But you’d have to have a magic molecule.
Now, I don’t think the Elelphant Man looks anything like an elephant either, so consider this:
-There is a general 50-60 yr cycle of temps, and we were warming from roughly 1980 to 2005, and are now apparently into the cooling half of the current cycle.
-Sometimes the trivial needs to be stated explcitly: if temps are stable, then energy in = energy out. If we’re warming, then energy out < energy in.
-The observation that we had been warming only suggests the latter. It in no way proves or disproves any particular mechanism. The "explanation" in the article only assumes CO2 to be responsible.
-The rather poor correlation between temp trends & [CO2] over the past century or so should make us consider factors other than CO2 to be more important in the process.
See also:
http://www.altenergyaction.org/Monckton.html
For a treatment on Monckton’s errors.
A hello to Tom Clark, glad the pointer brought people there and you here.
And thank you for something else I found at your page there:
Yourcenar’s words “let us try, if we can, to enter death with open eyes.”
g LaMoto,
Wrong on almost all counts
1)”There is a general 50-60 yr cycle of temps…”
Nope!
http://tamino.wordpress.com/2009/12/31/cyclical-probably-not/
http://tamino.wordpress.com/2009/12/22/cyclical-not/
2)”Sometimes the trivial needs to be stated explcitly…”
This is the only point you got right. Congrats!
3)”The “explanation” in the article only assumes CO2 to be responsible.”
Nope!
CO2 is a has been known to be a greenhouse gas since the 1850s, and anthropogenic CO2 was predicted to cause warming in 1896. Please, please, please read this:
http://www.aip.org/history/climate/index.html
4)”The rather poor correlation between temp trends & [CO2] over the past century or so…”
Well, damn! Wrong again.
http://bartonpaullevenson.com/Correlation.html
Given that you got every point wrong–and badly so–except the most trivial, why not go to the Start Here button and begin learning the science?
Gavin says, “Actually, “Lord Monckton” is completely made up as a title. ”
Actually, it’s completely understandable that he should make this mistake. For years, wherever he shows up, people have been saying, “Oh, Lord…”
Tom Clark says, “I recognize that “scientists” don’t play hunches based on local experiential phenomena, but guess what? Normal humans do. And the news from here is: hey, something’s happening, and the only reason “scientists” haven’t been saying more about is that they didn’t see it coming.”
OK, scientists predicted this El Nino about 5 months before it actually happened. And you are taking us to task because we didn’t force our way into the living room of every American, hit them upside the head with a two-by-four to rip their attention away from American Idol and say, “Hey, we think it’s going to get warmer…”?
I’m sorry, but at a certain point you just have to wonder whether the species is too stupid to survive.
tom clark@186
As another “non-scientist” on the Canadian coast north of you, I have been paying attention, and don’t find it’s current condition “significant” in isolation to much except the 2010 Olympics. Investigate the science yourself [links to the right or “start here” above] to put to rest uneducated assertions about what scientists have been saying – any El Niño event is “classic”, and many of we “normal humans” consider “something’s happening” as very old “news”.
Tom Clark @186 said:
“There has been a call for observations concerning current climate trends, but I don’t see that anyone has noticed the development of a significant El Niño event in the Central Pacific, with powerful effects now beginning to be felt on the California coast (where I live). It’s already shaping up as a classic El Niño, the most potent in at least twelve years. I recognize that “scientists” don’t play hunches based on local experiential phenomena, but guess what? Normal humans do. And the news from here is: hey, something’s happening, and the only reason “scientists” haven’t been saying more about is that they didn’t see it coming.”
—-
Not sure what you mean by “they didn’t see it coming”, or that no one is paying attention. To the contrary…
From December 16, 2008, NASA GISS Surface Temperature Analysis
“Summary: The Southern Oscillation and increasing GHGs continue to be, respectively, the dominant factors affecting interannual and decadal temperature change. Solar irradiance has a non-negligible effect on global temperature [see, e.g., ref. 7, which empirically estimates a somewhat larger solar cycle effect than that estimated by others who have teased a solar effect out of data with different methods]. Given our expectation of the next El Niño beginning in 2009 or 2010, it still seems likely that a new global temperature record will be set within the next 1-2 years, despite the moderate negative effect of the reduced solar irradiance.”
(my emphasis)
See also this latest NOAA report. NOAA observed that ENSO had switched into the El Nino mode about last June.
Dont spend time and energy on ‘Monckton’, just concentrate on the science. The number of posts increasing on here about this guy begins to look like paranoia ! Not needed…..