I while ago I wrote an article – Do Trenberth and Kiehl understand the First Law of Thermodynamics?
It could have been very short. “Yes”.
However, I did produce an extremely basic model to demonstrate that simple systems with heating “from within” can lead to outcomes that – for many people – are unexpected.
A huge admirer of this blog has written an embarrassingly pro-Science of Doom post entitled:
Why ‘Science of Doom’ Doesn’t Understand the 1st Law of Thermodynamics
So I thought I would return the favor by sending readers to take a look. At the very least, the blog writer will have the comfort of a small lift in visits as well as the welcome opportunity to explain their unique point of view. I just hope that my readers realize that their gushing praise for this blog does not involve any payments whatsoever.
And with apologies to the mysterious Dr. Philips who has had no part (ever) in the writing of this blog.
And on a less important note, if anyone is wondering how a PVC hollow sphere, heated from the inside and sitting in space has anything to do with the planet Earth – I can only hang my head in shame as it clearly has nothing whatsoever to do with our amazing planet.
A PVC sphere is nothing like the earth. The atmosphere is not made out of PVC. Conduction is not an important mechanism in climate physics. What was I thinking?
In any case, I fully expect the author of the laudatory blog article to change the title to something like “Why ‘Science of Doom’ Doesn’t Understand that the Atmosphere Isn’t Made out of PVC”.
And on a small technical note, let’s hope that the article writer fixes up the tiny technical mistakes in their article. If PVC can’t “transmit” radiation then conduction will be required, and.. ouch..
The Science of Doom 
It would be simple to make an experimental setup of this thought experiment (less power, external temperature well above 0K and so on…). But reality is reality. I bet you win, steve 😉
Did they come up with and answer about where the energy goes instead?
It does seem that hockeyschtick is having a little trouble with the difference between energy and power, which one is conserved and which one is relevant to equilibrium. If (when?) I make such a mistake (hopefully not rudely), I hope someone will politely correct me.
As I pointed out earlier, your model would have made more sense intuitively if you had assigned a size the the central heat source, so that it would also have a temperature. The source temperature would have been higher than the walls of the inner sphere. The temperature would drop as one progressed from the central heat source to the inner wall and then the outer wall. Of course, there are power sources that aren’t required to have a high temperature. I wonder what hockeyschtick’s analysis of a microwave oven would turn out?
I also thought your model had more to do with our planet (or perhaps Venus) than you intended. While writing a reply about the size of the central heat source, I began to think of the central heat source as being analogous to the earth and the heat source being the solar radiation absorbed by the surface. And I imagined the central heat source being the same size as the inner sphere, so that the PVC would insulate the heat source in the same way that the atmosphere “insulates” the earth. Conduction of heat through the PVC became somewhat analogous to convection of heat through the troposphere, but we have good equations for modeling transport of heat by conduction (and not convection?). The clear take home lesson is that things can get really hot when there is no effective route for energy to leave. The amount of sunlight striking the surface of Venus apparently is only a tiny fraction of that reaching the surface of Earth, but radiative cooling is ineffective because the mean free path of photons is so short, making it is extremely hot. Buoyancy-driven vertical convection only occurs when the lapse rate is too steep (negative).
Dear me– what a distressing dog’s breakfast at hockeyschtick. If that’s the kind of thinking that’s typical of a group that actually has influence on policy decisions, we’re in serious trouble.
SoD – I think the Hockeyschtick post isn’t going for a refutation so much as a “refudiation”…
It’s frustrating to see so much misconception over there, and to realize the light will probably never dawn among the Hockeyschtick commenters. Nonetheless, keep up the great work!
FYI, blogger MS over there doesn’t seem to have posted my most recent comment; likely there’s a delay. Anyway I was trying to point out that his imaginary 1st law dealt with power, while the real one deals with energy, but unfortunately I didn’t keep a copy of the comment. Anyway, it may or may not show up later, just wanted to make note of it here.
First of all let me thank you for your wonderful work from Italy. Some people will never be convinced, nevertheless this is incredibly helpful for someone new and really willing to understand something.
I found myself speaking to some contrarians here in Italy. They have their own First and Second law of thermodynamics too, of course. Speaking to them, I realized what could be one big conceptual problem for them. I will try to explain it here:
1) We usually treat systems at equilibrium, i.e. the PVC sphere model, or earth itself.
2) In this systems you get surfaces emitting at fluences higher than the incident ones, and this puzzles lots of people that are not familiar with physics.
3)In my opinion the problem arises from two aspects:
a) Steady state treatment
b) “Infinite energy source”, i.e. the sun or your 30kW super light bulb
4) The present post at the hockey schtick highlights very well the problem:
http://hockeyschtick.blogspot.com/2010/06/why-conventional-greenhouse-theory.html
Look at the fifth figure of the post. Of course it is wrong, nevertheless if one makes the thought experiment with a light pulse instead of a continuous beam, it is nearly impossible to get the energy balance wrong. All the confusion arises from one fact: The photon reflected by the mirror sum up with the photon emitted by the lamp in a second moment. I know it is pretty trivial, but I think that the conceptual problem is there.
5) Let’s take your PVC model and turn on the light-bulb at t=0. Light first reaches the inner wall and is part absorbed and part reflected, the conductivity heat sink begins to work, and thermal emission from the inner wall also begins. In the mean time the light bulb goes on shining. But after t=t0 inner surface will be reached by “direct light” + reflected light”+ “heat”. This will build up more and more radiation inside the cavity. In the meanwhile the heat sink becomes more and more efficient, until equilibrium in the cavity is reached
6)I think that this kind of dynamic picture (explained in a much better fashion than mine), could help to understand how the inner surface can emit much more power than the super light bulb. A clear treatment of the transient inside the cavity is key.
Best Regards
I added my final comment at that entertaining blog.
With delicious irony, the blog owner – who started his article to “defend” the 1st law of thermodynamics – has happily, and openly, tossed this unimportant law aside to help demonstrate my original article false.
If you look at the K-T diagram, the 342w/m^2 incoming solar is matched by the outgoing 235w/m^2 plus the 107w/m^2 reflected shortwave. The rate of radiation emission of everthing else inside the system does not affect these figures.
A couple of things to note however.
1) I agree wih S.o.D’s analysis of the first law as it works in the simple system posited in the linked post. As S.o.D says, this is just a simple model to make a point, and bears no direct relationship to the Earth, the sun, or the detail contained in K-T’s diagram.
2) The Earth is never in equilibrium and these figures are not set in stone. The sun’s inactivity just shrunk the ionosphere by 30%. No-one knows yet what effect that has on lowering the altitude of the tropopause, but you might suspect it could be bigger than the ~1% increase in the effective height of the outward radiating surface of the Earth’s atmosphere notionally due to an increase in co2 (asuming the drop in humidity since 1948 hasn’t more than offset it anyway).
3) Although the K-T climate cartoon balances overall, they could be well off with some of the detail inside the system. Especially the amount of heat convected up through the atmosphere rather than being transferred by radiation.
In summary, S.o.D.’s linked post shows that Keihl and Trenberth know enough about the first law to make sure they picked figures for outgoing LW and reflected solar that add up to the total incoming solar radiation, but it doesn’t show that Keihl and Trenberth know enough about the the internal figures in the budget.
Giovi Pelle,
I think that you have some good insight into the difficult concepts for some people.
I think that there are a couple of other things as well, and that in general SOD does an exceptional job of discussing some of these simple errors in detail.
On point 3) I would add that people get confused about the relationship between heat and temperature. For example when you have an ‘infinite energy source’ (ie. finite source that persists for an infinite amount) that it’s not just the rate of the source that determines temperature, but also the rate that the body gives off energy. So long as the body is accumulating heat, it’s temperature increases, etc.
I also think that people can sometimes make a mistake which is fine so long as they’ve put some effort into justifying their position (such as some simple back of the envelope calculations) and are willing to admit when they’ve made a mistake.
It’s ironic reading through the comments on hockey schtick when they start out by accusing SOD of violating the 1st law and then scramble to try to justify their position by arguing about photon cancellation, etc.
I have to wonder if figure 5 from the link you provided is actually evident of an error or if it is deliberate, because really it’s not that difficult to work out, even with a continuous source. It’s more that it depends on people glancing at the illustrations and not thinking about it too much.
Congratulations to MS on The Hockey Schtick for rewriting their article. It takes great strength of character to do something like this.
My earlier ironic statements about the relevance of this model is something to discuss on a much later day.
Today is a beautiful day.
Strength of character?
That is debatable, given that the blogger trumpets “12 years of cooling” with an accompanying trend graph using 1998 as a starting point.
Adam R.:
Saying you were wrong publicly is a sign of strength of character.
Being right about everything isn’t a sign of strength of character and not a necessary prerequisite.
I agree that the strength of character was there and it was a beautiful day, but it only lasted one day. The Hockey Schtick has now taken down the apology and said:
Commenter ‘Gord,’ source of the analysis in the post originally here entitled Why ‘Science of Doom’ doesn’t understand the 1st Law of Thermodynamics, was away from email for a few days and unable to respond to claims in the discussion. I unfortunately misinterpreted that he had dropped out of the discussion and therefore took it down with a “mea culpa.” Gord is now back and thus I have put the discussions back up to allow further debate.
So the original, terribly flawed, analysis is gone, but so is the admission that it was wrong and the apology to SOD. Apparently, whoever writes this blog felt so lost when they couldn’t reach Gord that they folded. Now that Gord’s great knowledge of how energy can be destroyed through wavelength disruption is back in play, the blog owner wants another go.
I kinda like gordisc’s… it would mean i can stick a glow plug in a rotary vein vaccum pump, and run it backwards as an engine, without it turning into a blob o molten metal! 😉
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