There are, dear Bunnies, more whackos under heaven and earth than even Eli could shake a stick at. While in the case of climate change denialism it often appears that these are from the out the window right, to be fair, some are on the left and others, well, they are simply commuters from Mars. This makes for very strange bedrooms. A prominent example from the left is Alexander Cockburn,John Farley, has a Monthly Review article taking this apart. Rabett recommends. To give a taste (two tastes per customer), John's take on two incessant denial-o-whines are worth cutting out and putting in our wallets. That the European Warm Period is not there in the MBH reconstructions is a golden oldie. After pointing out that the warming was a) not synchronous globally and b) not global, at least synchronously the article gets to the root of the thing
Those who believe that the Medieval Warm Period is very important are making the assumption that there is only one factor determining the climate. If you make that assumption, and if the sole factor is burning of fossil fuels, then our understanding of global warming would be challenged, because of course massive burning of fossil fuels did not happen in medieval times. Some six decades ago, many scientists in fact assumed that only one factor influences climate, although they couldn't agree on what factor, and global climate change was thus not understood. Today we know better: a number of factors influence global climate, including the intensity of the sun, aerosols, the greenhouse effect, Milankovich cycles (changes in the Earth's orbital motion), volcanic eruptions, and other factors.Second, Eli understands that several WUWT readers have had Kenneth Trenberth's comment
The fact is that we can't account for the lack of warming at the moment and it is a travesty that we can't.tattooed on the same parts of their body as the Christmas fairy tried to light. Farley brings the context (Eli knows that's unfair)
What climate scientists do not fully understand are the short-term fluctuations above and below the long-term trend. As part of those fluctuations, energy is transferred between different parts of the earth's climate system: glaciers, polar ice, the deep ocean, etc. Trenberth asks why the January 2008 temperature was unusually low. "Was it because a lot of heat went into melting Arctic sea ice or parts of Greenland and Antarctica, and other glaciers?" Currently we just can't say.Oh yeah, Cockburn doesn't understand the second law of thermodynamics. John does.
Comments
On reflection, it never fails to amaze me that G&T thought up and then managed to get published such a basic error regarding the Second Law. It's the sort of confusion you'd expect from a less clever undergrad.
ReplyDeleteOh. I thought this post was going to be about the underpants bomber.
ReplyDeleteCIP
I'm intrigued by the mention of where the heat is, and whether it could be accounted for by melting ice. If you look at the calories needed to convert ice at, say, -5C, to water at +5C, you need a LOT of heat energy to effect the phase transition for a few hundred billion tons of ice per year (counting losses from GIS, WAIS, and the Arctic Ocean). I don't know climate science well enough to gauge exactly how that might translate into things like the "omega" weather pattern currently chilling the UK, for example, or the cold in parts of the US.
ReplyDeleteIt's not hard to imagine this being a "normal" part of a warming cycle--the ice sucks up a lot of heat, leading to slightly colder winter weather in some places, but also causing quicker ice melt and albedo flip in the summers.
High-latitude omega blocking patterns have been observed frequently ever since we had the capability of making the appropriate upper-level measurements to define them. (See, for example, The Extensive Cold Air Outbreak of January 24-31, 1951). While the frequency and intensity of such events might be affected by a warming climate, any such connections would be highly speculative.
ReplyDeleteKramm has been compounding the thermodynamic errors over on my blog:
ReplyDeletehttp://arthur.shumwaysmith.com/life/content/the_arrogance_of_physicists#comment-4612
He seems to think entropy is conserved, or something, going on about entropy fluxes as if that was the important question. And DS = 0. Right. I think the problem is these guys never got a basic grounding in thermal physics before going off and doing their other stuff. Some people just skip that class I guess.
Vaguely amusing stuff, Arthur. I can't quite figure what Kramm is trying to say. Staples says G&T are right, and then comes back around and says they're wrong. I'm not sure what's going on there.
ReplyDeleteI agree on your assessment on what goes wrong here. When people make errors that would be apparent to somebody taking an undergraduate level class, I can only conclude that they don't need to understand that material in their work. When they then moonlight as experts on something else, they don't have the self-awareness to realise they're relying on hopelessly garbled memories of something they should have learned long ago, but don't actually apply in their own research. To top it off, they often make appeals to their own authority, which makes the whole thing somewhat comic.
"Those who believe that the Medieval Warm Period is very important are making the assumption that there is only one factor determining the climate."
ReplyDeleteActually, I'm more interested in how it is that "skeptics" came to believe that a Medieval Warm Period existed at all. Absent paleoclimate reconstructions, the only evidence as far as I know consists of anecdotal accounts from Medieval European history.
To use that to argue against paleoclimate reconstructions is sort of like arguing against the fossil record because it fails to turn up any elves.
I'm also interested in the history of how skeptics came to believe so passionately in a globally synchronous MWP, in the absence of global reconstructions. The regional anecdotal evidence was surely known in certain circles, but I'm guessing the average skeptic never heard of the MWP until the backlash against MBH 98. But I don't know.
ReplyDeleteEgad, Eli, where were you three years ago when Cockburn first erupted?
ReplyDeletehttp://adamant.typepad.com/seitz/2007/05/nation_denounce.html
Could our former next President's peculiar "it's millions of degrees inside the earth " take on geophysics stem from reading Cockburn in The Nation ?
Russell, some nuclear waste Eli leaves to the pros.
ReplyDeleteCarrot eater writes:
ReplyDelete"When people make errors that would be apparent to somebody taking an undergraduate level class, I can only conclude that they don't need to understand that material in their work. When they then moonlight as experts on something else, they don't have the self-awareness to realise they're relying on hopelessly garbled memories of something they should have learned long ago, but don't actually apply in their own research."
I think you have that exactly right. Classical thermodynamics is a notoriously tricky subject, loaded down with traps for the unwary (and for the wary as well.) Few undergraduate courses in physics or chemistry provide much in the way of conceptual understanding of these issues - the textbooks have all the right words, but the exams have tended to be dominated by algorithmic problems or long strings of partial derivative manipulations. Unless you are subsequently forced to confront these concepts in your research - and a typical physics or chemistry major is not likely to be forced to do so - you are likely to forget them.
I have many times said about some subject, "I never understood it until I had to teach it." For thermodynamics, I had to teach it about three times before I felt I understood it.
RP,
ReplyDeleteYou expressed it very well. I can count maybe 4 classes I've taken that can be called thermodynamics; I've lost the feel for much of it. I crack open a book as needed, but don't really feel confident. Though in defense of my professors, my exams were not formulaic, but rather nicely conceptual. I thought.
But the topic I TA'd, I had more of a lasting understanding. Teaching it 3x sounds like a good metric.
Eli really likes Fermi's short book on thermo. Not complicated, but subtle.
ReplyDeleteHmm, reminds me that I did TA it. My first intro to thermodynamics was a book borrowed from my Dad (the chemist) I think when I was still in high school; full of partial derivatives and such that were way beyond me, but I was intrigued. Then I had a rather hopeless undergrad class on thermal physics (from a teacher who probably should have been emeritus by that point, he'd been a dean or something). Then an excellent statistical physics class which resolved everything for me. There might have been one or two in between - I remember a graduate course on critical phenomena which was pretty heavy on the thermo stuff, and I did some undergrad research on related stuff too. And then I was TA and had to actually lecture once a week to a bunch of undergrads on the subject, from yet another book. I guess it's pretty deeply ingrained by now, even though it really wasn't that close to my main subject of study...
ReplyDeleteHere's a neat little thermodynamics paradox, due to Kelvin: the "ice heat engine." Start with a column of liquid water at a temperature just an epsilon above the freezing point. Put a weight on top of the column. Lower the temperature by epsilon - the water freezes and lifts the weight. Slide the weight off the column horizontally (for the purposes of this thought experiment we can neglect sliding friction). Now raise the temperature by epsilon, so that the water melts. Lower the weight (thereby extracting work), and slide it back on. This returns us to the original configuration, weight on water. Voila, a perpetual motion machine of the 2nd kind ! It converts heat to work at (within epsilon of) a single temperature.
ReplyDeleteWhat's the resolution ?
I have taught Thermodynamics to undergraduates for over 10 years now, and I learn something new each fall when I teach it. I agree with Eli that Fermi's book is good. Another good book is "The 2nd Law" by Henry Bent.
ReplyDeleteKramm clearly doesn't understand entropy over at Arthur's blog. In fact, he doesn't even show an understand at the level of general physics or chemistry. He sets forth a thought experiment in which he defines the sun as the system and space as the surroundings. Then later, he calls the space "thermodynamically unimportant" The surroundings of an open system are "thermodynamically unimportant"? Even a freshman learns that unless the system is isolated, the surroundings are important.
I love puzzlers.
ReplyDeleteI'd normally the effect of little differences in pressure on water, but that's got to be the kicker here. Put the weight on top, you change the pressure, and you change the melting point. If even by just a little bit. That's my gut.
That would say, "I'd normally neglect..."
ReplyDeleteThe smart bunny answer to RP^2 is when you slide the weight onto the water, it falls to the bottom unless the density is less than 1 gm/cm3. Then you don't have a problem.
ReplyDeleteThat's smart ass, not smart bunny
ReplyDeleteWell, ok, but Eli thinks it does have something to do with the problem. Modify the set up in the following way, let the separation between the water/ice and the world be a frictionless membrane and the other side of the membrane be a sealed piston. Work is done on the air in the piston by the water when the water freezes and work is done on the water by the piston when it melts. The net work is zero.
ReplyDeleteanonymous way back up there, and immediately subsequent carrot eater:
ReplyDeletei've always assumed the obsession with the MWP was some sort of brain-damaged attempt to counter the "unprecedented warming in $bignum years" point illustrated by the hockey stick.
after all, if it was this warm before, and humans weren't responsible then, it can't be our fault this time, can it? and lack of response is clearly due to the undeniable strength of that argument, and not because it's rather hard to type and facepalm at the same time.
RP, I'm no perfesser, but isn't the trick that the energy needed to change the temperature plus friction makes for a losing proposition? I'm thinking this has to be way too obvious, though.
ReplyDeleteWell, following Bloom, let's see. Is it really a PMM2 after all?
ReplyDeleteYou can say epsilon is really really small, but it's still finite. So you still need an external heat source to raise the temp by epsilon, and an external sink to lower again by epsilon.
So really, you aren't extracting work from an isothermal isolated system. By neglecting to tell us how the heating and cooling is done, you tried to trick us into thinking it was an isolated system, but it isn't. (At least, you got me to neglect that, the first time around).
You've got a cyclic process with a Th and Qh and Tc and Qc. The heat input is only partially converted to work.
All should be well.
I'm also years removed from thinking in this way, so I could still be wrong.
ligne: That's the emotional motivation for them hang on to the MWP, once they've heard of the possibility. I thought the question is more, where did the idea come from in the first place?
ReplyDeleteLooking around, it was a known term in paleoclimate, though it was always ambiguous whether it was a local or global event. It appeared in the IPCC FAR of 1990 and each subsequent report, and it was discussed in MBH99 itself. MBH99 sources it to Lamb, 1965.
I'm assuming that nobody in 1975 was walking around feeling very strongly about the MWP. So maybe it became the rallying cry after the appearance of MBH98/99, and anybody reading MBH99 would have become aware of the idea.
I wonder why they don't just use the previous interglacial. Sceptic: It was warmer in the previous interglacial, and there were no SUVs then! Response: That may be the case. SUVs aren't the only forcing on earth. So what?
Carrot Eater, you ought to go with your gut - it's instincts are sound. The pressure dependence of the melting point is indeed the key to the solution - it turns the arbitrarily small ("epsilon") temperature difference into a finite delta T, the difference between the freezing point of water under the pressure of the weight and the melting point of ice after the weight is removed. That difference, while small, is just enough to ensure that Carnot's requirements are satisfied.
ReplyDeleteSee: James Thomson, _Theoretical Considerations on the effect of pressure in lowering the freezing point of water_, Cambridge and Dublin Mathematical Journal, Vol. 5, p. 248, 1850.
James Thomson was the older brother of William Thomson, who would later become Lord Kelvin. William discovered the apparent paradox, and James came up with the solution. (Moral: if you think you've discovered a way to circumvent the Second Law, run it by your elder siblings before publishing.)
So my gut is OK. What's wrong with my head? The latent heat for the phase change is being supplied by something, or being released to somewhere. So this can't be a closed system. It's exotic, but I don't see why a heat engine can't have a working fluid that remains at essentially the same temp, but is changing phases due to contact with a heat sink and heat source.
ReplyDeleteI suppose I could draw it on a T-S diagram and/or calculate the entropy changes. But I'm hoping somebody else will do it for me.
My favorite reply to the "only-one-factor-determines-climate-so-it's-not-us" thinking is that observing a bird in the sky doesn't disprove gravity.
ReplyDeleteLonger version here:http://ourchangingclimate.wordpress.com/2010/01/06/a-quick-n-dirty-guide-to-falsifying-agw/
Bart
Of topic (and rarely even discussed), but probably far more important than anything else at this late date.
ReplyDeleteThe elephant in the room: the failure of Copenhagen and the inevitable failure of carbon trading schemes.
James Hansen and the economists who invented emissions trading (to deal with a well constrained SO2 problem) are not the only ones who recognize that carbon trading will likely not work and that a carbon tax with dividend is the better approach.
Nobel economist Joe Stiglitz also does (Joseph E. Stiglitz: Overcoming the Copenhagen failure
"Perhaps it is time to try another approach [than carbon trading]: a commitment by each country to raise the price of emissions (whether through a carbon tax or emissions caps) to an agreed level, say, $80 per ton. Countries could use the revenues as an alternative to other taxes -- it makes much more sense to tax bad things than good things. Developed countries could use some of the revenues generated to fulfill their obligations to help the developing countries in terms of adaptation and to compensate them for maintaining forests, which provide a global public good through carbon sequestration."
Stiglitz quote end
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Great pieces by Farley, though in the earlier article on the case for AGW the piece on CO2 residence time could be a bit clearer:
ReplyDeleteIt has been estimated that of 100 molecules of CO2 injected into the atmosphere, 6 molecules will dissolve in the ocean in 1 year; 29 molecules will dissolve in 10 years; 59 molecules will dissolve in 60 years; 84 molecules will dissolve in 360 years; and the last 16 molecules will take over 1,000 years.
Denialists will just crow: how do you get 194 CO2 molecules from 100?!
Bart is right, Eli read his gravity defying post earlier this morning.
ReplyDeleteAs for the Joe Stigliz mouse, surely you have heard of Eli Rabett's simple plan to save the world.
Best recommendation for a climate tax
Bleh, lost a comment to cyberspace.
ReplyDeleteTrying again: I retract my previous comment. I think this is a PMM1, not a PMM2. Now if Kelvin thinks it's a PMM2, I'm most likely wrong, but can somebody sort me out?
You have ice. You bring in heat source at Th and transfer in Qh, Qh = latent heat of melting. The level goes down.
You then put a weight on top, and introduce heat sink at Tc. You extract Qc, which is the same latent heat of melting. The level goes up, the weight goes up, and you can extract work from the weight.
To me, this is a violation of the First Law. Qh = Qc, but yet there is a W. This cannot be, and the cop-out is the pressure dependence of the phase change.
But beyond that, where is the Second Law problem? Heat flows from Th to Tc. Check. Why does the Second Law care that the working fluid is isothermal, in this case with a phase change?
It violates Kelvin's version of the second law - "it is impossible for a heat engine operating in a cycle at a single temperature to do any net work" - if T_h can be made arbitrarily close to T_c (as the paradox assumed.) When you take into account the pressure dependence of the freezing point, T_h and T_c must differ by a finite amount, approximately (dT/dP)(delta p) where delta p is the pressure exerted by the weight.
ReplyDeleteThe pressure dependence of the freezing point implies that the heat of fusion also depends on pressure. To lowest order, it's probably ok to assume that the entropy of fusion is independent of pressure, which would give you delta_S/T_h and delta_S/T_c for the heat of fusion at the two pressures. I think that rescues the First Law.
Hmm. I knew the Kelvin statement of the Second Law as "no heat engine can be 100% efficient". Meaning, there has to be some energy wasted through transfer to the heat sink at Tc.
ReplyDeleteBut nevermind that, I'm with you. If you draw a Carnot cycle on a T-S diagram, the work extracted is the area of the box (Th-Tc)*(S2-S1). If Th = Tc, then the amount of work done is zero. And if Carnot is the best you can do, then absolutely no heat engine can extract work if Th = Tc.
I'll do it quantitatively for the phase change example later, to really convince myself.
Thank you for the instruction.
Dear yea-mon:
ReplyDeleteThanks for the kind words about my 1998 piece in Monthly Review.
You didn't like the arithmetic in one sentence, so let me clarify it [with additions in square brackets].
It has been estimated that of 100 molecules of CO2 injected into the atmosphere, 6 molecules will dissolve in the ocean in 1 year; 29 molecules will dissolve in 10 years [including the 6 molecules in the first year]; 59 molecules will dissolve in 60 years [including the 29 molecules in the first 10 years]; 84 molecules will dissolve in 360 years [including the 59 molecules in the first 60 years]; and the last 16 molecules will take over 1,000 years.
-John Farley
We have the old issue, that there is an interchange btw the atmosphere and the ocean, so that when the number of CO2 molecules in the atmosphere increase, they are not the same CO2 molecules. CO2 molecule have no hair as it were. Then you have the problem of how do you explain this to the clown with the large red nose.
ReplyDeleteCheers John,
ReplyDeletethat's fine, though from my viewpoint of battling denialists* on the net even simpler is best. I'd go for something like this, cutting out the cumulative totaling altogether:
"It has been estimated that of 100 molecules of CO2 injected into the atmosphere, 6 molecules will dissolve in the ocean in 1 year; an additional 23 will have dissolved at 10 years; an additional 30 at 60 years; 25 more at 360 years; and the last 16 molecules will take over 1,000 years to dissolve."
* Though in my opinion it's a battle that can't be won - the winning is in getting those who would be (in absence of a dissenting voice) swayed over to denialism on the side of science.