One of the most important features of science is that theories can be used to explain observations we have already seen and also predict outcomes of experiments not yet performed. Engineers particularly appreciate this feature of science speeds up the production cycle. In contrast, astrology: not so much.
Because this feature of science is so valuable, I am always interested in testable predictions and, when possible, learning whether experimental data support a particular theory. With that in mind, I want to propose a radiation experiment involving a simple geometry. I’d like to challenge Claes Johnson to apply equation (21) in his Computational Black Body Radiation to develop a predictive formula for a special case. I will, in turn apply the more traditional equation (20) in Claes Johnson’s manuscript to determine the temperature.
Afterwards, I will invite “The Bunny” (who seems to like to rig up these things and may have appropriate equipment at hand) to find two thermocouples some sort of resistive heater, figure out how to create vacuum where we need it take some measurements and report back. (Anyone else who has equipment conveniently at hand is welcome to give it a go. Maybe some enterprising mechanical engineering student could convince a faculty member to approve this as a senior project, and later write a paper to submit to the ASME student writing contest? The context might make it more interesting that other papers.)
Here is the simple problem:
Under the assumption in the figure below determine the heating rate per unit surface area, $latex \displaystyle q’ $ , required to maintain red surface at at $latex \displaystyle T_{s} $
$latex \sigma(T_s^4 – T_b^4) $
(Although I may be missing something, since I do not see a green plane.)
Incidentally, this is why it feels colder in your house in the wintertime when the walls are cold, even though the air temperature, as measured by the thermostat, is supposed to be comfortable.
Julio-
Drat. Initially I had a more complicated problem…. I’ll fix that when after I get the curry simmering.
Julio–
You are appear to be using (20) which, if I understand Johnson correct is supposedly wrong. We ‘should’ use his (21) which will give quite different answers for many values of the two tempertures.
I’m hoping to get Johnson attention, verify what I think we get based on his answer and then get “The Bunny” (or other) to do the experiment in a lab. The experiment should require ability to create a vaccuum, set up the plates, create a vacuum etc. I don’t have access to suitable equipment. But someone might.
Even if we don’t get Johnson’s attention, it’s easy enough to show what his equation (21) seems to give as the answer. Then if the Bunny does the experiment…. well… the answer (21) seems to give will likely shown to be wrong. (After all, we know the equation you give has worked for zillions of problems especially the simple ones!)
Lucia,
Sorry if I jumped the gun!
I haven’t tried LaTeX here before. What did I do wrong?
It’s the old thermos problem… but without the reflective silver (aluminum) coating. Can Claes Johnson get it right? I doubt it.
You certianly could find the necessary lab equipment.
You could use a glass condenser like any found in an organic chemistry lab, to hold the liquid and a resistive heater where the current and thus the heat could be varied to maintain temperature.
Use a vacuum pump to evacuate the cooling side of the condenser.
Put the whole apparatus in and oven once the curry is done.
See how much current is needed to maintain a temperature.
Turn on the oven and recheck the amount of current necessary.
Repeat and plot.
I don’t know if finding out that the temperature of the sink will have an effect on the source will change anyone’s mind.
But in order for Cleas Johnson to be right requires that the photons involved in the radiative heat transfer know both from whence they came and to where they are going.
So let’s fix the Standard Model so there is no global warming, works for me.
Julio,
You need to close with a $.
bobdroege
I live and work at home. I’m not a chemist, don’t have access to a wet lab &etc. The bunny is a chemist and might have the stuff on hand.
With a budget and time, I could put it together. But I figure that other people may already have access to the material (or not.) If I suggest…. someone may do. I would rather monitor voltage and current to figure out the amount of heat added though. I’m not convinced your oven idea is quite right. I need the inside and outside at different temperatures. I also need some thermistors or thermocouples to mount on the plates.
Thanks, Lucia!
Wasn’t Dr. Roy Spencer doing some experiments along these lines a while ago? (I don’t think he actually had a vacuum, though.)
I’m curious to see this mysterious Eq. (21) now.
I should point out that the answer would be different for a cylindrical geometry (Steve’s thermos). In fact, the cylindrical geometry seems to result in a paradox that I’m not sure how to resolve right now!
Julio,
No, Roy was making an insulated box with a very thin layer of plastic film on one side (almost transparent to IR), and showed that the temperature inside the box at night (radiative losses) became colder than the ambient air surrounding the box. This was to try to prove that radiative physics is correct; not sure how much success he had among those who were not sure to begin with. I thought it was a cute experiment.
Julio,
“In fact, the cylindrical geometry seems to result in a paradox that I’m not sure how to resolve right now!In fact, the cylindrical geometry seems to result in a paradox that I’m not sure how to resolve right now!”
You mean that the energy received by the smaller radius surface is too high for it’s temperature?
Julio–
Click the link to Claes article in the blog post. I’ll write up the “standard” solution and Claes tomorrow. With luck, we’ll get someone with a lab to do an experiment– that would require a bit of time. Maybe Eli will want to do it– or not. But I think because this is a book and the topic of climate change gives this a hook, it could make a fun senior topic. Maybe someone with access to seniors who need topics could assist them in designing it properly. (I’d be happy to comment on things that people need to consider to mimic “infinite”, and what one might need to measure.)
The cylinder problem “paradox” is resolved by understanding view factors. Energy radiated from a surface actually radiates over a hemisphere. Some form the “outer” surface doesn’t hit the inner surface. It’s classic. 🙂
Lucia,
My reference to a thermos is a confusion, due to t he geometry. Your thought experiment (infinite parallel surfaces) is simpler… but maybe difficult to do in practice. 🙂
Lucia,
“Some form the “outer†surface doesn’t hit the inner surface. It’s classic.”
“from” I think, but the parallels in great minds are astounding…no no, only joking. 😉
Lucia and Steve.
I get it. Thanks! (This is definitely a problem we should not ask in the candidacy exam if we do not want to have a revolt on our hands, but it’s a shame, because it’s really neat, actually…)
Julio,
Actually, I think it is a good question to pose… if it is qualitative. Pressing someone to work out both the math and the radiative transfer would be a challenge in an exam.
Julio–
Dealing with the dewar or body inside a sphere is a classic question. If you put it on a test, you’d find is the students who were already familiar with that specific question would know what the answer was, and if you just asked the demonstrate the issue two ways, to show they confirm, either they’d do their integrals for the view factors right, or they’d make a stupid mistake. The others would scratch their head a while before they remembered “view factor”.
You’d have to word the question very carefully to make sure the test measured what you want it to measure.
I presume Ts<Tb ??
Jae– you got your sign backwards. The “s” surface is heated and is warmer than the “b” surface.
Curse you Lucia, Eli actually read the thing and it is risible. If nothing else go to Section 7.14, read it. Then think how unlikely it is that there are no IR measurements with a spectrometer pointed upwards. HINT: there are, you see what you expect Yes Claes, there is IR backradiation, it exists, the spectrum and intensity has been measured and modeled. Early work extends back about a century.
So let’s go back to the beginning. There is back radiation. Claes Johnson is simply wrong when he says there is not. Forget the math, the basic claim is sausage.
I think a simpler experiment would be to suspend a mass in a vacumn with a constant source of heat (small resister and stable current perhaps). Let it come to an equilibrium temperature. Then place several un-heated masses around it or have them already there and just move them closer or even have a cylinder slide down around the center mass.
If the theory of back radiation is correct, the center mass should increase in temperature even though the input energy is held constant. If Dr? Johnson is correct the center mass should remain at it’s equilibrium temperature.
My apologies if this is this what you have designed and I just didn’t get it.
The basic errors start way before eqn (21).
Eq (4) has solutions that grow exponentially, exp(t/gamma).
He has almost shown this himself in eqn (10).
For long waves (small nu) and zero forcing,
(10) has solutions A exp(t/gamma).
So his eqns have a very fast instability – exactly what he
was incorrectly claiming happens in the conventional picture.
Between (4) and (5) he makes an elementary error in his integration by parts. He tries to convert an integral of the the first and third derivatives of u with respect to t into the square of the second derivative. But his integration variable is x!!
Is this guy really a math professor???
Hmm,
4σT^3*(T − Text) → 4σT^4 : as Text → 0
not the σT^4 the author correctly quotes for
“the energy radiated from a blackbody of temperature T into an exterior at absolute zero temperature (0K)”
R ≈ 4σT^3*(T − Text) is of course true if ≈ is read as “approximately equal to” but so what. It gives results that can be out by a factor of 4, which the author must surely concede, so “approximately” covers a heap sins.
I cannot see the point of this. If the author had written an equation:
R = 4σT^3*(T − Text)
It would be obviously false, but the author hasn’t and I expect with the reason that whether it be true or not is moot.
Pekka explains why there is no back radiation. Go look. Claes has a radical way of using Maxwell’s equations, and few have understood it.
Still, he’s wrong that its going to give different results. Pekka seems to be the only one who catches Claes’ drift.
==========================
If you’re curious you’ll want to see why all your criticisms about ‘back radiation’ miss the point. Read Pekka’s answer to Judy, who is right there with all the rest of you.
Pekka still doesn’t think the application of this method will produce results any different than the standard method, but that is another question.
The meat is at the bottom of the thread, most of it this morning.
====================
Definition of back radiation please. I know radiation, I know spherical / random radiation but back? define
I quote Pekka @ 6:17 this AM:
“In this approach the back radiation is replaced by some properties of the media which lead to a similar change in net radiative flux. In this approach there is no back radiation, but a reduction in ‘forward radiation'”.
======================
Here is a real-world example of theory versus reality.
Table Mountain CO, for a 24 hour period on November 17th, 2010. This is one of the SurfRad stations.
Measured Solar, Upwelling IR and Downwelling IR bear no resemblance at all to the actual surface energy level changes.
http://img12.imageshack.us/img12/3225/tablemountainnets.png
http://img140.imageshack.us/img140/4109/tablemountainall.png
Something else is going on. Closer to Pekka’s explanation.
Given two objects, one of which is directly heated and radiates energy, part of which is absorbed by a second object and heats it, back radiation is radiation from the second object absorbed by the first. In the limiting case the second object has no source of energy other than the radiation absorbed from the first.
The NET effect is to slow the rate of energy loss by radiation of the first object by returning a portion of the energy emitted. Both objects will be warmer than they would have been in the absence of the other. The net emission from the system will be the same, equal to the energy input.
Eli pointed to a direct measurement of back radiation from the atmosphere above.
There are numerous discussions of such systems on the net, for example go poke around Science of Doom. Eli has a couple too. Atmospheric physics books discuss this in terms of shells, ME heat transfer books describe this sort of thing in detail (and they get VERY detailed).
Bill–
There may be difficulties with specific theories ability to quantify the upwelling and downwelling radiation in the atmosphere. But Claes Johnson is going further– and if he is right, then furnace design, insulation design, have only worked out by accident. His equation will not work for this simple configuration Stefan Boltzman will.
Kim–
Puleeze! If you are going to tell people to read Pekka’s stuff, either
a) post the url to the comment or
b) give us enough identifying information to find the specific pekka comment. The best way to do that is to quote some of the answer!
There is no way I am going to plow through a 500 comments searching on “pekka”, particularly as many of the comments you advise us to read border on nonesense.
It would be very useful to have a link to the manuscript where Bill Illis’ graphs come from, but they are indeed interesting, perhaps not in the way he thinks.
For example, take a look at the second one, around 18 hours zulu when the sun is up. The interruptions in the radiation from the sun by clouds are seen as a rapid oscillation and at the same time the downwelling IR (backradiation) increases.
Once you recognize this increase in backradiation when clouds pass over, there are even more interesting things at about 12 hours zulu, where Eli (and hopefully the dear readers) now recognize the passage of clouds as shown by the increase in downwelling IR, accompanied by an INCREASE in upwelling IR from a warmer surface.
Care to link to the source Bill?
lucia @ 67583
Yeah, it’s threaded and a mess. But I did quote from him, and I told you the good stuff is this morning and at the end of the thread.
Hey, I point. You gotta look.
No demands here. Satisfy your curiosity.
=================
I mean it’s nested. Judy gets Pekka’s point.
==============
Bill Illis,
.
There are a couple of things missing from your graphs that explain the lack of rapid energy accumulation at the surface:
1) Convective heat transfer away from the surface
2) Reflected visible wavelengths (that is upwelling visible)
.
The lack of energy accumulation just shows that all energy flows (including the two I noted) net to near zero.
.
What I find interesting about the second graph is that the changes in upwelling and downwelling infrared with the passage of clouds look small compared to the reduction in downwelling solar energy. That is, the clouds (probably convective, due to modest surface warming) cause a very strong net reduction in solar energy at the surface; many times more than their influence on IR flows. AKA a strong negative cloud feedback (a la Willis Eschenbach).
The SURFRAD raw data for Table Mt. CO station are here:
ftp://ftp.srrb.noaa.gov/pub/data/surfrad/Boulder_CO/
I don’t think that the net surface energy means what Bill Illis thinks it means.
“Surface Energy Budget
The energy or heat budget at the earth’s surface, considered in terms of the fluxes through a plane at the earth-atmosphere interface. The energy budget includes radiative, sensible, latent and ground heat fluxes.”
NOAA definition
http://www.nws.noaa.gov/glossary/index.php?letter=s
You can get plots of the SURFRAD data here:
http://www.srrb.noaa.gov/surfrad/pick.html
I don’t see a surface temperature column. The air temperature varies a lot. I also don’t see how if the surface temperature changes, which it clearly does as the radiation level implied by the surface temperature isn’t constant, that the net surface energy doesn’t change. Perhaps Bill could enlighten us as to how that’s calculated.
Re: lucia (Comment#67824)
I suspect this is a difference between physicists and engineers. Engineers are taught about “view factors.” Physicists, apparently, are expected to figure them out on their own!
Re: Alexander Harvey (Comment#67837)
Perhaps some of the confusion arises from the fact that
4σT^3*(T − Text) is a halfway decent approximation to the correct formula as long as T is much larger than the difference T – Tex (which is often the case when one is talking about ordinary air temperatures)
Example: Tex = 273 K, T = 293 K, difference 20 K
T^4 – Tex^4 = 1.82*10^9
4 T^3 (T – Tex) = 2.01*10^9
or a 10% error.
Again, I think everyone is wading into dark waters. I’m not going to argue about radiation, I don’t know that much. However, something is clearly wrong with some parts of radiation theory because the radiation is escaping into outerspace at a faster rate than has been calculated. Obviously this has not been widely accepted but it must be the case. Either that, or you have to endorse the Trenberth “missing energy” belief which is much dumber than anything Claes Johnson is trying to do.
DeWitt Payne (Comment#67869)
February 2nd, 2011 at 10:18 am
http://www.srrb.noaa.gov/surfrad/pick.html
I don’t see a surface temperature column. Perhaps Bill could enlighten us as to how that’s calculated.
——————————-
Its the Stefan Boltzmann implied radiation level from the 2 metre air temperature (which can be accessed at the right side of the variables).
Re: Bill Illis (Feb 2 19:08),
And, of course that’s the problem. The 2m air temp is not the surface skin temp, especially on a cold late fall night. The skin temp, which can be calculated from the upwelling IR, will be cooler at night and warmer during the day and will have a smaller phase shift w.r.t. the incoming solar radiation. It’s also not going to be a good predictor for downwelling radiation either as a lot of that comes from higher up where it’s colder and varies less. From the graph of downwelling IR, it looks like it was a cloudy night, not to mention the wind was blowing and shifting around the compass.
Since the air temperature isn’t the surface temperature you can’t use just the temperature to calculate changes in enthalpy. You have to calculate moist enthalpy for which you have to know the humidity. It looks like that information is in the meteorological data too.
It’s the other way round Shoosh
Hey, are there any answers you guys don’t own? Holy cow.
I was reading this a bit this morning:
http://data.giss.nasa.gov/gistemp/abs_temp.html
“The Elusive Absolute Surface Air Temperature (SAT)
Q. What exactly do we mean by SAT ?
A. I doubt that there is a general agreement how to answer this question. Even at the same location, the temperature near the ground may be very different from the temperature 5 ft above the ground and different again from 10 ft or 50 ft above the ground. Particularly in the presence of vegetation (say in a rain forest), the temperature above the vegetation may be very different from the temperature below the top of the vegetation. A reasonable suggestion might be to use the average temperature of the first 50 ft of air either above ground or above the top of the vegetation. To measure SAT we have to agree on what it is and, as far as I know, no such standard has been suggested or generally adopted. Even if the 50 ft standard were adopted, I cannot imagine that a weather station would build a 50 ft stack of thermometers to be able to find the true SAT at its location.
Q. What do we mean by daily mean SAT ?
A. Again, there is no universally accepted correct answer. Should we note the temperature every 6 hours and report the mean, should we do it every 2 hours, hourly, have a machine record it every second, or simply take the average of the highest and lowest temperature of the day ? On some days the various methods may lead to drastically different results.”
Q. What SAT do the local media report ?
A. The media report the reading of 1 particular thermometer of a nearby weather station. This temperature may be very different from the true SAT even at that location and has certainly nothing to do with the true regional SAT. To measure the true regional SAT, we would have to use many 50 ft stacks of thermometers distributed evenly over the whole region, an obvious practical impossibility…blah blah blah
…and on and on yet you continue to argue over fractions of one degree on a chart supposedly representing the entire planet. Then on top of that a huge portion of this planet is in the grips of a giant cold blizzard. Amazing.
It’s called averaging.
Liza, apologies if we had a similar discussion a few months back.
70 million years ago, during (what turned out to be) the final era of the great dinosaurs, large parts of earth were covered by tropical forests. Snow and ice were rarities, seen on mountaintops and at the poles.
18,000 years ago, the earth was in the grip of the Wisconsin Ice Age. Continental glaciers buried (what would become) Canada and the northern U.S. in kilometers-thick continental ice sheets. Ditto for northern Eurasia. Smaller ice sheets covered all the major mountain ranges — Himalayas, Alps, Rockies, and so on.
2 Questions.
1 – Thinking about that time in the Cretaceous, would it be fair to say “the earth was warmer then, than it is now”?
2 – With reference to that time in the Pleistocene, would it be fair to say “the earth was cooler then, than it is now”?
Even if there are spots on present-day earth that are warmer today than they were during the Cretaceous? And other spots on present-day earth that are cooler today than they were during the glacial maximum?
ISTM that Surface Air Temperature is a useful metric for thinking about this concept of warmer/cooler. If so, it’s not “bla bla bla.”
If SAT isn’t useful, than what concept would serve more effectively? Mean energy content per m^3 atmosphere at STP? Mean radiation per m^2 surface? Or would it be more precise to limit our vocabulary to qualitative terms like “warmer” and “cooler”?
A postmodernist might be offended by the very idea that a climate of the past was knowably different from that of the present. But that hasn’t been your stance.
For reference, in a recent thread, Carrick discussed what the term useful means to people engaged in measurement activites.
“It’s called averaging.”
Averages give you no useful information.
“the average rainfall on Earth”
“the average temperature of the Pacific Ocean”
“the average human being”
Not only do these things sound silly they give you no useful information. Temperatures on Earth have a huge spread. Two different places could be 100 degrees or more apart. And each place could have a hundred reasons for the temperature there (which probably has NOTHING to do with C02 content in the atmosphere) And as the link says you are averaging numbers with no universal standards adopted…and even if some are adopted now or decided on now, there is no evidence of any standards exactly the same in the past data… and “now” whether it be 20 yrs or 50 that is not enough time or evidence to say “unusual temperatures” are happening on Earth.
Re: Julio ,
Engineers do an awful lot of engineered applications with very weird geometries. So, one will almost always have to apply a principle to an ugly looking problem. View factors help. Just knowing how and why the view factor matters without solving the whole problem can be useful to design. Sometimes, you know you just need to fiddle with the view factor and not solve the rest of some particular problem.
There are ‘methods’ for hydrostatics found in engineering books that physicists might skip since specifically finding the center of mass and center or pressure isn’t always faster and easier than just computing intergrals. But, once again, can be to have a convenient non-time wasting method to apply to potentially weird geometries and which provides convenient variables for later applications.
AMac (Comment#67918) February 3rd, 2011 at 8:40 am
I know we’ve had this conversation before. 🙂
Yes so the Earth has ranges of temperature during climate events. Just like the Earth has ranges of rainfall all over land and sea.
Give me a range of “Global Average temperatures” .
Global average temperature is anywhere from this…to…this. And then tell me what is normal or not. Was the MWP not normal? Was the LIA not normal? There wasn’t a problem with CO2 then was there? And give me a range of time in direct proportion to REAL climate events (warmer or cooler) on this planet. The LIA lasted 400 yrs plus did it not?
Its the same old argument. However with the comments from the climate crowd and Al Gore lately it’s looking more and more silly to more and more people. We can google and present articles written just 10 yrs ago proclaiming because of GW “the children” soon won’t know what sledding is like or a snow day off from school is.
Here from:
http://www.drroyspencer.com/
IA Challenge to the Climate Research Community
February 2nd, 2011
“I’ve been picking up a lot of chatter in the last few days about the ’settled science’ of global warming. What most people don’t realize is that the vast majority of published research on the topic simply assumes that warming is manmade. It in no way “proves†it.
If the science really is that settled, then this challenge should be easy:
Show me one peer-reviewed paper that has ruled out natural, internal climate cycles as the cause of most of the recent warming in the thermometer record.
Studies that have suggested that an increase in the total output of the sun cannot be blamed, do not count…the sun is an external driver. I’m talking about natural, internal variability.
The fact is that the ‘null hypothesis’ of global warming has never been rejected: That natural climate variability can explain everything we see in the climate system.”
He asks better then I do. 😉
@Eli Rabbet
No it isn’t the other way around. If you look at the last 10,500 years, 86.6% have been warmer than 2010. Therefore, we can conclude that man has little to no influence on temperature. This is because temperatures should be currently higher, if agw theory were correct. In fact this is a good question for everyone here. How can agw be true if it has been warmer for most of the past 10,500 years than 2010? If agw was a true, temperatures should be higher right now but they are not.
Re: liza (Feb 3 09:04),
Any thoughts on my 2 questions in #67918?
If your answers are No, well then I don’t have more to add.
If your answers are Yes, a follow up.
Question 3 – Can the “warmth of the planet” at different times be arranged in order?
E.g.
Warmest
75m yrs ago, Age of Dinosaurs
1100 AD, Medieval Warm Period
Today
1750 AD, Little Ice Age
12,000 yrs ago, Younger Dryas
18,000 yrs ago, Wisconsin glaciation
Coldest
I’m not certain this order is correct (I think it is, though). I’m asking whether the exercise of coming up with such an arrangement is kosher. Or is trying to do this sort of comparison meaningless, do you think? (Again, if you think so, some postmodernists would certainly agree.)
[Edit – Re: #67925 – Liza, I think Roy Spencer wouldn’t have any hesitation in responding to Question 3, “Sure, we can arrange those snapshots from Warmer to Colder, no problem!” What do you think his answer would be?]
AMac (Comment#67927) February 3rd, 2011 at 9:29 am
“2 Questions.
1 – Thinking about that time in the Cretaceous, would it be fair to say “the earth was warmer then, than it is now�
2 – With reference to that time in the Pleistocene, would it be fair to say “the earth was cooler then, than it is nowâ€?”
When I think of these “times” I don’t think of ONE NUMBER representing temperature for the whole time period. Do you?
There would exist a RANGE of temperatures. This list is useless for arguing over FRACTIONS of one degree now.
The problem is the use of the word “warmer” NOW as a call for fear and panic when it could be in the RANGE of natural climate flux on this planet.
Re: liza (Feb 3 09:41),
Your answer wasn’t entirely clear. But I gather that you don’t think that it’s fair to say “the earth was cooler during the Wisconsin glaciation 18 ky ago, than it is now.â€
But aren’t you troubled by relying on Roy Spencer, assuming (which I think is safe) that he’d have no trouble with the conventional answers to Questions 1 – 3?
ISTM that Roy, Eli, and me agree a lot more among ourselves on this matter, than any of us agree with your perspective?
AMac (Comment#67932) February 3rd, 2011 at 10:00 am
Whether I think its fair or not about “warmer or colder” has nothing to do with “average” temp being used now to scare people. I think you are just trying to get away with the concerns/problems I linked to about the surface temperature. In fact data resolution going back that far wouldn’t help at all because the data can’t show such small time frames such as now.
I have pointed to the Blue Holes research many times here and you all just yawn and ignore. Data from those holes via sea level high stand marks (forget temperature); show climate swings that happened fast. As fast as a human lifespan. Many many many times in the Earth’s recent past.
I think Bill Ellis has shown here before that even during glacier advance periods the temperature wasn’t the thing so much (especially in approx fractions of a degree) as it was the melting of the snow in the summer months or not. (I believe my husband has told me before it only takes 50 ft of snow to get a glacier forming.)
Liza, you never gave straight answers to three simple, straight questions. Which is fine.
It can be fun to have wide-ranging conversations that veer among scaring people, Blue hole research, ranges of natural climate flux, and other topics.
It can also be useful for the conversants to stay with a single subject. I learn stuff that way.
You’ve avoided saying that there is any way of definitely thinking about a “warmer” or “colder” earth. So I now believe that you don’t think there’s an objective way of doing so. Much less a way of gathering physical indicators (temperatures or something else) to quantitate this “warmer/colder” scale (when it comes to planets, that is; I’m sure you find thermometers useful in the oven, etc.)
I think more concretely than you do. So, if I thought there was no way of quantitating warmer and colder, “climate swings” or “natural climate flux” or Roy Spencer’s challenge couldn’t have any meaning for me. I wouldn’t talk about them any more than I’d discuss fluffy integers or happy asteroids.
Anyway, thanks for reading and responding. Cheers, A
“the earth was cooler during the Wisconsin glaciation 18 ky ago, than it is now.â€
AMac,
And the above statement isn’t entirely clear. For example, do you mean all points on the earth were cooler? Some images presented on this site showed that not all areas on the earth are trending warmer “now”. Are we talking absolute temps for our comparison?
We should keep our comparisons like to like.
Andrew
Re: Andrew_KY (Feb 3 11:16),
> And the above statement isn’t entirely clear.
Suppose I have two ovens, but unfortunately both were poorly made — they leak, the insulation’s uneven, the heating elements in each are off to one side. I can’t even read the dials.
Anyway, I turn one on to setting “A” and the other to setting “B” and wait a while.
Which one is “warmer”?
I could (and will) specify that I’m interested in the average temperature of these ovens. Over a restricted range (heh) of temperatures, that’s an acceptable proxy for the physical property of greatest interest, akin to the total heat energy in each.
In this scenario, questions would arise about sampling, and about determining the adequacy of any particular sampling strategy. And about many other issues.
And it might turn out that my readings won’t allow me to determine whether oven #1 at setting A is warmer than oven #2 at setting B, to within a prescribed statistical significance.
Those are different concerns from “there’s no such thing as ‘average temperature,’ or as ‘heat content.'”
I don’t spend a lot of time worrying that some people apply postmodern ideas to scientific and technological questions.
But I don’t often engage in conversations on the subject, because there’s only so much for me to learn. We just see things differently.
“the earth was cooler during the Wisconsin glaciation 18 ky ago, than it is now”
The problem with his question Andrew is that we are still in this ice age.
So he is asking basically if it is fair to say the climate is “warmer” during a glacial minimum within the current ice age?
Um yes it is.
So what’s all the worry about again?
AMac,
I agree that “average temperature” is a reasonable idea .
And I agree, as you have illustrated, that determining the meaning of the phrase (in the context of ‘the earth’) is subject to a lot of complications that have yet to be adequately explored.
Andrew
@Amac
I have not been following your conversation with Liza but I think my point is relevant. Over the past 10,500 years, the temperature has been warmer than 2010 86.6% of the time. Agree?
Next, since it has been warmer for most of the time before 2010, can we conclude that agw is false because the temperature has been higher for the large majority of the past 10,500 years? I mean, shouldn’t the temperature now be higher because of global warming? Please give me your thoughts.
@shooshman
I have not been following your conversation with Liza but I think my point is relevant. Over the past 10,500 years, the temperature has been warmer than 2010 86.6% of the time. Agree?
I’m curious where you got this number from; looking at http://en.wikipedia.org/wiki/File:Holocene_Temperature_Variations.png it seems that your assertion is incorrect.
@Andrew and Liza
I think to keep things simple, us 3 should use the same baseline. Just use the past 10,500 years. The question is, given that it has been warmer than 2010 86.6% of the time, how can anyone claim global warming? For most of the past 10,500 years, there was no industrial revolution. So it has been NATURALLY warmer 86.6% of the time over the past 10,500 years. Shouldn’t current temperatures be warmer now than the past 10,500 years? I eagerly await the responses.
@Jhudsy
http://wattsupwiththat.com/2010/12/28/2010%E2%80%94where-does-it-fit-in-the-warmest-year-list/
Here is the link I used to make my assertion. Also, I don’t like to suggest one source over another but you might be interested to know that wikipedia had to fire a guy named william connolley because he was editing global warming pages and taking the medieval warm period graphs off of wikipedia.
@Shooshman
The graphs in the article you reference are with regards to Greenland ice cores, not global temperatures. If you read the method in the link I posted, you’ll see that it coincides with the light blue line in the figure.
@Jhudsy
You are correct. However, here is what Bill Illis said
“The d018 isotopes are the best temperature proxy we have. It has been proven in hundreds of examples to reasonably reflect the temperature of the time. And this goes back hundred of millions of years. It might not be perfect, but it is the best proxy we have got.”
It is hard to say that the ice cores accurately reflect global temperatures. However, Richard Alley used the same ice core measurements and used them to show global temperatures.
Perhaps Lucia can indulge us and make a post, showing both graphs. Then everybody can argue over which one is more accurate. Insert smiley/frown face.
@Shooshman
I don’t see how the Bill Illis quote is appropriate, the Wikipedia link I posted makes use of a number of ice cores, all of which make use of oxygen isotopes to infer temperature. The difference between it, and the link you posted is simply the difference between measuring temperature at one location and many. The Wikipedia figure does use other proxies to obtain additional accuracy.
I don’t think it’s possible to say that the Greenland ice core figure is “more accurate” than the Wikipedia one, as the former is simply a subset of the latter. Or am I misunderstanding what you are trying to say?
Re: Dr. Shooshmon, phd. (Feb 3 13:17),
It seems a reasonable first-pass interpretation to me, that more of the past 10,500 years have been warmer than 2010, than have been colder. Maybe 86.6% (+- 10% or 20% I’d guess) — I can’t say for sure how accurate or precise this proxy might be.
Like paleotemperature reconstructions of the past 1,000 and 2,000 years, that provides some potentially useful context for the AGW discussion.
But I digress. This elides the point of where Liza and I first part ways. For a given planet — Earth, say — I accept the idea that there is a useful concept called “surface average temperature.” SAT can be calculated from measurements, and the accuracy and precision of an SAT estimate can also be calculated.
If a pereson can’t subscribe to the ideas in preceding paragraph, then we’re with Humpty Dumpty in Alice in Wonderland right from the start. “Words mean what I want them to mean, no more and no less.”
That’s a time sink, not a discussion.
No I’m not saying one is more accurate than the other. I don’t use wikipedia anymore because of the whole connolley thing. That said, the graph on wikipedia is probably fine. It would be interesting to see a post on here comparing the 2 figures.
@Amac
Hahaha that is a great reference to Humpty Dumpty. Humpty Dumpty was a childhood hero of mine. I still say he was pushed off that wall!
@Amac
So would you agree with my point that I make on almost a daily basis to Lucia that there is no reason to use 1979 as a starting point when talking about temperature because it basically implies that history didn’t start until then. And I’m not saying we need to start the record at the point of the earth’s inception. The farther we go back, the more arguments will be created as people question the accuracy of measurements and assumptions made when reconstructing the temperatures. Having said that, why use 1979 though? So people can show a temperature increase and make it look special? I understand that 1979 begins the satellite record, and I do indeed trust the satellite measurements more than anything but why not use a time scale of thousands of years, including 1979-present?
Wow, Easterbrook came under heavy fire I noticed in the postings about his graphics. Lucia, this needs to be discussed. There is some absolute clown over there going by the name of “From Peru” who keeps claiming that Dr. Easterbrook cut off one of his graphics at 1905. Which graph did he cut, how is From Peru claiming it is dishonest anyway because he includes graphics that go up to the year 2000. Furthermore, he has several paragraphs mentioning the most recent years.
Dr. Shooshmon, phd. ,
In #67968 you proposed a post I should do. Please refer to WUWT rule 9 modified for the blackboard
Granted… I proposed The Bunny do an experiment so Eli would have a right to make fun of me for later complaining you suggest I write certain posts. But still… You might want to consider reducing the rate at which you suggest posts I could write.
You want a blog where the blog host discussed topics you chose? Start your own blog.
Re: Dr. Shooshmon, phd. (Feb 3 15:17),
> So would you agree with my point that I make on almost a daily basis to Lucia
No.
Are you guys still at it? 🙂
Jhudsy (Comment#67970),
That holocene plot from wikipedia we’ve all seen before (that’s fine) but it isn’t exactly “global average surface temperatures”.
It says:
The main figure shows eight records of local temperature variability on multi-centennial scales throughout the course of the Holocene, and an average of these (thick dark line).
(That dark line is what they’ve added)
it also says:
Because of the limitations of data sampling, each curve in the main plot was smoothed (see methods below) and consequently, this figure can not resolve temperature fluctuations faster than approximately 300 years.
Hello. This is important especially when you are claiming a decade or two worth of temperature now is “unusual”. You don’t know that.
It goes on:
Further, while 2004 appears warmer than any other time in the long-term average, and hence might be a sign of global warming, it should also be noted that the 2004 measurement is from a single year (actually the fourth highest on record, see Image:Short Instrumental Temperature Record.png for comparison).
So they are comparing thousands of years of temperatures fluxing up and down all the time; (C02 concentrations be damned) and tell you they can only see time frames no smaller then 300 years in this data (meaning we don’t know how the “GAT” looks in the past in time frames smaller, no body does) ; and as I began, comparing it to ONE YEAR, 2004 of modern data
It goes on:
It is impossible to know whether similarly large short-term temperature fluctuations may have occurred at other times, but are unresolved by the available resolution. The next 150 years will determine whether the long-term average centered on the present appears anomalous with respect to this plot.
You could say in truth; the “climate” hasn’t changed hardly at all in general from that graph!!! ..except maybe since the LIA which is a “colder period” within the current ice age. 😉
Here is the last 635 million years from the do18 proxies. The coldest periods were 635 Mya when it was -25C and then during the Ordovician extinction at 443.4 Mya when it was -7C or so.
The warmest periods were the Pangea-Permian at 265 Mya and the Cretaceous at 95 Mya.
http://img214.imageshack.us/img214/9508/tempco2570mlefttoright.png
Other than that, what did I do now?
I think Dewitt Payne has already shown I need to calculate the surface energy levels differently. I still need to figure that out but is there something else I didn’t do right.
I just calculate things and chart up the results because I think talking about things doesn’t help at all. We need to cruch the numbers to understand what is really going on and you always learn something new that you hadn’t talked about when the real numbers are put together.
Richard Alley did not calculate the Greenland temperatures properly. It was a successful exaggeration used to scare everyone about the Younger Dryas.
Re: Bill Illis (Feb 3 21:11),
What’s the provenance of that nice-looking chart? Did you make it yourself, or does it come from the literature?
It’s hard for me to say very much about a compilation that must involve a great deal of synthesis and splicing of disparate data types… except that it’s pretty, and tells an interesting story!
AMac (Comment#67989)
February 3rd, 2011 at 9:22 pm
—————————–
It is all published data. It is just the CO2 data and then a higher resolution (less smoothing) version of the same chart produced by Globalwarmingart. [The smoothing function used actually distorts the timelines a little so I used a statistical program which keeps the data centred on the right date].
http://www.globalwarmingart.com/wiki/File:Phanerozoic_Climate_Change_Rev_png
AMac: It seems a reasonable first-pass interpretation to me, that more of the past 10,500 years have been warmer than 2010, than have been colder.
.
You also fell into the trap.
.
However, in contrast to “Dr” Shooshmon, I trust that you will understand the problem in making claims about 2010 using data that ends in the mid-19th century.
Re: toto (Feb 4 06:44),
Thanks for that link to the article “Easterbrook’s Wrong,” dated Jan. 4, 2011. It provides sufficient backstory on the relibility of the proxy-based analysis that Dr. Shooshmon linked in #67963 in support of his assertion that 86.6% of years in the past 10,500 years have been warmer than 2010.
Let me rephrase what I wrote in #67971:
“It seems a reasonable first-pass interpretation to me”, even though “I can’t say for sure how accurate or precise this proxy might be.”“Congratulations, Dr. Shoosh, you pwned me.”The record is fine as a dO-18 based proxy of temperature on the Greenland ice sheet — it’s GISP2. As toto’s link shows, Easterbrook’s interpretation of that record is wrong on several key points. Some can be ascribed to ignorance and carelessness. Others are willful, in particular a mirror-image of the “hide the decline” data splice/torture.
Shoosh, you skipped due diligence and parroted a misleading argument. What, if anything, are you going to do about it?
How about no chart on Earth made by humans means anything you think it means; and on top of it all 100ppm of C02 does not change the climate of the whole planet in any way shape or form and certainly NOT how it’s dished out and fed to the public by these smooth operators run amuck with their alarming “warming” proclamations; represented in fractions of just one degree of temperature on silly little graphs.
Hi liza,
I think that AMac is stuck is the he said/she said world of virtual climate science. He’s never going to find out what’s actually going on until he decides to do something about it himself instead of relying on declarations by virtual climate science “authorities”.
Andrew
It’s likely that you’d be quite opposed to the cultural Marxist Antonio Gramsci, on doctrinal and political grounds. Yet the style of discussion in the latter part of this thread is taken right from his playbook.
Here’s a view of Gramscian tactics by Jimmy Cantrell.
Or, we could dump Gramsci’s ideas along with the rest of postmodernism, and get back to science. That would be my preference.
“Or, we could dump Gramsci’s ideas along with the rest of postmodernism, and get back to science. That would be my preference.”
AMac,
Mine too. But I’ve discovered that if you want something done right, you have to do it yourself. Sitting on the couch with your laptop and regurgitating what other people say, without verifying any of it, is not science.
Andrew
@toto
“I was a little surprised. I thought that recent temperatures were the warmest for at least hundreds, and probably thousands of years. ”
Way to go. You find some hack who doesn’t believe in the medieval warm period (what a surprise, this doesn’t happen every single day) and he references Richard Alley, who also doesn’t believe in the medieval warm period. Hey toto, looks like you fell for the trap you idiot.
toto why don’t you just admit you don’t believe temperatures have ever been higher than they are now. That article you link to makes no sense. There is absolutely no misrepresentation in the graph whatsoever, I don’t even know what this guy is referring to about the supposed “1855” cutoff date. I don’t see that in any of the graphs…furthermore he has several paragraphs about recent temperatures.
Andrew and Liza, I think it is safe to say at least half the people here believe Michael Mann’s graph is correct. How many will openly admit it, I suspect very few due to cowardice. I don’t know what the point is anymore. The guy blatantly, blatantly cheats on a graph and the response is “no, he didn’t cheat. Big oil companies have put pressure on scientists. Today’s temperatures are unprecedented.”
@Amac
Here’s what I’m going to do. I am going to give you and toto, 0 dollars and 0 cents. The rebuttal piece toto posted makes no sense. The least the author could have done was place an arrow to indicate what the hell graph he is talking about because Easterbrook has at least 10 graphs posted on the link.
Anyway, I’m pretty sure most of the top scientists would agree with my position. Having said that, I do know this doesn’t mean anything to a lot of people here.
Given that the discussion has suddenly moved away from the science to personal attacks, I don’t think there’s much point in responding to Liza’s question to me.
Thanks to toto for the linked article.
Here is Dr. Happer’s response:
“One could haggle about details, but Easterbrook is basically right. He is talking about the “Holocene climate optimum†or the “Holocene thermal maximum.†There is a massive amount of data that shows that high latitudes were several degrees warmer than now over much of the past 10,000 years. There are many places in Northen Europe (I am personally familiar with sites in Norway and Scotland) where the evidences for a much warmer climate in the Neolithic (mid-Holocene) is overwhelming. The cult is doing its best to cope with this fact, and the rebuttal piece is pretty typical. Google on Holocene climate optimum or Holocene thermal maximum and form your own judgment.”
-Dr. William Happer (fired by Al Gore)
Jhudsy–
Some day I need to write a filter that recognizes when the email conversation has dwindled down to repetitious comments by … well… people who are just very repetitious. Symptoms include but are not limited to
* three comments in a row by the same person.
* someone posting ‘you idiot’. (I’m going to add that to the automatic rejection spam filter.)
Hey Lucia, you previously stated you didn’t believe Dr. Happer was fired by Al Gore. He has stated himself he was fired by Al Gore so would it be safe to say you think he is lying? Also, since it is quite evident now that you favor Michael Mann, Gavin Schmidt and company, why not rename the site realclimate2?
Personally, I think it is shameful and cowardly on your part to allow commenters to get away with false and misleading claims about past temperatures. Or are you a Mannian and believe his graph is correct?
I
I apologize for letting my temper get the better of me, in the tone of my remarks this morning. I’ll again thank toto for the informative link, and leave it at that.
Shoosh
What I wrote was this:
I would also like to point out that the comment is not only an attempt to threadjack onto a pet topic of yours, but consists of “argument by rhetorical question”. Three out of four sentences are rhetorical questions.
I’ve decided control your persistent attempts at threadjacking to irrelevant topics (like political appointees being fired for political reasons. The horror!) I am now going to add “Happer” to the list of words on the “spam” list. If you try to get around this, or continue to decide to threadjack, call people idiots, argue by rhetorical question or do something similar, I’m going to moderate you until you behave.
Yeah that’s par for the course Amac. I second the thanks to toto for the link. How stupid of me to think a scientist from Princeton would know the answer.
@Lucia
I’ll save you the trouble, I’m just going to quit visiting here. You are a coward. You won’t answer the question. When you duck a simple question, it is very telling about your personal bias. The whole reason I came here in the first place is I thought there was objectivity to this site. Boy was I wrong. Your right, political appointees being fired for political reasons doesn’t mean anything, besides the fact that the guy who fired him went on to advance a false theory and has resulted in billions of dollars being wasted. “Yawn” indeed.
I recommend that nobody continue visiting this site. The refusal to acknowledge the MWP (or any flaw about AGW for that matter) is very telling about the extreme bias. Peace out and don’t let the door hit ya where god split ya.
Dr. Shoosh,
“There are many places in Northen Europe (I am personally familiar with sites in Norway and Scotland) where the evidences for a much warmer climate in the Neolithic (mid-Holocene) is overwhelming. ”
.
There is for certain a lot of evidence for higher temperatures in the early to mid Holocene, especially in the Norther hemisphere, since summertime solar intensity was ~7% higher than today, and the ITCZ appears to have been well north of where it is now during the Northern summer; no surprise there. WRT to Norway and Scotland: if you are referring to tree-line altitudes, then you should keep in mind that there has been a lot (up to hundreds of meters) of isostatic rebound in these regions, and that rebound may complicate the tree-line data. Part of the apparent Holocene cooling in previously glaciated regions may be due to gradual increases in local altitude.
Says Dr Shoosh: “I’ll save you the trouble, I’m just going to quit visiting here.”
If true, I sure wish I had not wasted my time on comment 68019. Oh well.
Bet quatloos on if Dr. Shoosh returns?
Nah.
Thank god. I thought he’d never leave.
toto:
You feel into another one: Gareth is claiming that Greenland measurements wouldn’t be a proxy for long-term global temperature measurements.
At the least he would need to provide evidence why this is true: One would expect long-duration trends in Greenland to echo planet wide temperature changes.
This is an example of confirmation bias, in my opinion.
This is how I interpret the Greenland ice core data using the most appropriate conversion factors given its latitude and altitude. -10.0C for both Greenland and Antarctica in the ice ages. -5.0C global.
http://img841.imageshack.us/img841/9484/lasticeageglant.png
Bill Illis,
EBEX-2000 was an experiment to try to do a complete energy balance with closure. You need a lot more than just the surface radiation balance. I haven’t been able to find any publications that aren’t behind a pay wall. Here’s a link to an abstract of a paper:
http://ams.confex.com/ams/BLT/techprogram/paper_43687.htm
There’s a link on the page to an extended abstract with more detail.
The experiment was also discussed at Science of Doom here:
http://scienceofdoom.com/2010/07/31/the-amazing-case-of-back-radiation-part-three/
Re: Bill Illis (Feb 5 20:05),
You have Younger Dryas and the Antarctic cold reversal happening simultaneously in your graph. I was under the impression that the ACR started 1,800 years before YD. See this paper for example:
http://www.agu.org/journals/ABS/1997/97GL02658.shtml
DeWitt Payne (Comment#68179)
February 5th, 2011 at 9:41 pm
—————————–
There was actually an Older Dryas (14,400 years ago), a Younger Dryas (12,800 years ago) and a Youngest Dryas (11,200 years ago).
The Older Dryas was a more significant event in my opinion because it signaled a strong reversal in what was a rapidly warming climate between 17,000 and 14,500 years ago. Temperatures got to -1.0C or so by 14,500 years ago and then rapidly fell back down again between the 3 events.
I’ve got the Older Dryas switch happening first in the Greenland ice cores – about 300 years before the Antarctic ice cores. Generally it looks like Antarctica is leading the temperature changes in the rise out of the ice ages but not at the Older Dryas.
The fact that the Older Dryas is forgotten about is another Richard Alley legacy and another example of the climate science community perfectly willing to go along with the latest myth whenever it suits the AGW movement.
I forgot to add that temperatures fell by more in the Older Dryas than they did in the Younger event.
Dr. Shooshmon, phd. (Comment#68007) February 4th, 2011 at 10:26 am
toto why don’t you just admit you don’t believe temperatures have ever been higher than they are now. That article you link to makes no sense. There is absolutely no misrepresentation in the graph whatsoever, I don’t even know what this guy is referring to about the supposed “1855″ cutoff date. I don’t see that in any of the graphs…furthermore he has several paragraphs about recent temperatures.
It’s clear you don’t understand, here’s the quick explanation: ‘The Present’ for the purpose of Paleo data is 1950, the closing date on the graph is 95 years ‘before present’, i.e. 1855, simple really.