Guest essay by Paul Murphy
Here’s Wikipedia’s simplified but canonical description of the greenhouse effect:
The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases.
Solar radiation at the frequencies of visible light largely passes through the atmosphere to warm the planetary surface, which then emits this energy at the lower frequencies of infrared thermal radiation. Infrared radiation is absorbed by greenhouse gases, which in turn re-radiate much of the energy to the surface and lower atmosphere.
This greenhouse effect forms the basis for warmist doctrine: that human CO2 emissions are causing a catastrophic increase in the global average temperature.
Although people like Gaia theorist James Lovelock have predicted that global warming will kill billions of humans the belief that warming would be catastrophic for life on earth is largely unresearched and probably indefensible. There have been many extended warm periods in the earth’s history and the fossil records we have for them suggest that each produced more life, and a greater diversity of life, than the cooler periods preceeding them.
We have reasonable information, furthermore, on the Roman and Medieval warm periods and not only did each of these kick off significant civilizational development, but the polar bear made it through them embarrassingly undead and not a single estuarial or river basin culture, whether in Asia, Egypt, or Europe, is known to have drowned.
The Wikipedia article quoted above gives the two main facts warmism depends on: gases tend to emit heat at a lower frequency than they absorb it, and measured net solar radiation does not fully account for near surface air temperatures – but doesn’t directly raise the problem that the measured effect is roughly an order of magnitude too large to be accounted for by the known interactions between thermal radiation and atmospheric greenhouse gases other than water vapor.
This problem has produced a widespread search for a forcing multiplier – something which reacts to a small increase in atmospheric CO2 to force a big increase in atmospheric warming. So far, however, none of the candidates for this have withstood even friendly critical review – meaning that those who argue for CO2 as a primary source of a significant atmospheric greenhouse effect are committing themselves to the biggest magical hand wave since crystalline epicycles brought consensus to the Ptolemaic Universe.
The processes modeled in IPCC and related warmist calculations as this unknown climate sensitivity factor may exist in the real world – but every experimental effort to demonstrate that minor increases in atmospheric CO2 lead to major changes in surface temperature has failed to show a repeatable effect in anything near the right range:
- The biggest “experiment” on this is, of course, reality: CO2 concentrations appear to have gone up by more than 20% since 1958, but we have neither a clear definition of the average global surface temperature nor data to support the belief that any of the proxies we have for it have shown significant change over the period.
- The smallest and most often repeated experimental demonstration, the Al Gore tabletop special in which one jar contains a bit more CO2 than the other, produces essentially the same result if the same weight of an inert gas like argon is used in place of the CO2.
- It is easy to demonstrate the greenhouse effect by pointing a thermal imaging camera at the sky, but within the limits of Google and Bing searches it appears that no one mapping variations in the effect to variations in local concentrations of greenhouse gases other than water vapor and urban smog has demonstrated effects beyond the levels (roughly one tenth of the IPCC climate sensitivity assumptions) predicted by the theoretical calculation with no multiplier.
What we know of the earth’s climate history does not support the warmist indictment against anthropogenic CO2 emissions either: none of the warming periods recorded in human history can have been triggered by human CO2 production – and the longer term geological record seems directly contradictory too. Essentially all of the earth’s surface has been tropical at one time and glaciated at another, but nearly all of the information we have about the atmosphere during those periods suggests that CO2 concentrations rose during, but not before, tropical periods and fell significantly during, but not before, glaciations.
What we can say therefore about the belief that atmospheric CO2 increases are causing significant global warming is that it has no theoretical support, no experimental support, cannot be seen operating in the real world, and is contradicted by what we know of global climate history.
Where neither science nor history can explain warmism, politics can. Basically, if you’re someone like Al Gore whose political career is based on railing against American republicans, then an obvious reason for singling out CO2 as a threat to humanity’s future is that this is an easy sell: there is a grain of truth in the science, people can see smokestacks, the SUV is a widely approved target for angry rhetoric, and the political audience is generally eager to accept the burdens a demonstrated need to control national energy use would put on them.
Similarly, what we can say about the idea that global warming would necessarily prove net negative for life on earth is simply that this idea has not been extensively studied but seems to have neither theoretical nor experimental support and is contradicted by what we know about the history of life on earth, but meets the political need for players like Gore et al because people cannot be held hostage to the threat of a good thing happening if they don’t knuckle under.
It is important in forming personal beliefs about the relative roles of science and politics in warmism that we separate belief from reality: most of the alarmists seem to be true believers, most of the deniers merely Missouri skeptics, but there seems to be no objective evidence to suggest that either side genuinely knows whether the global climate is changing or not. Thus we can probably agree that the publicity now generally given a hot day in Death Valley and denied an extended cold emergency in Peru reflects an editorial agenda more than it does climate, but the combination of theory, data, and definitions we have is not sufficient to let us know whether either fell outside longer term climate norms.
The deeper issue here is not that the political action now strangling western economies is politically motivated, but that accepting the arguments for seeing warmism as sheer political fraud means accepting that the talking heads citing science to sell it to the masses are either deluded or dishonest – but because no wolf today doesn’t mean no wolf tomorrow, it also means that warmist politicization of the research process has to be seen as having destroyed the credibility of all involved, and thus as having greatly weakened the world’s ability to recognize and respond to a real threat should one now materialize.
================================================================
Paul Murphy, a Canadian, wrote and published The Unix Guide to Defenestration. Murphy is a 25-year veteran of the I.T. consulting industry, specializing in Unix and Unix-related management issues. This essay was originally written for consideration of the Matt Ridley prize.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Michel says:
November 5, 2013 at 12:19 am
——————————————————–
No, you are still not “getting it”. There is nothing wrong with radiative physics, but there is plenty wrong with the misapplication of radiative physics to our mobile gaseous atmosphere by climate pseudo scientists. There is a slight radiative greenhouse effect, most notable over land at night, but the net effect of radiative gases in our atmosphere is cooling at all concentrations above 0.0ppm
A good place to start in examining the fundamental mistakes of the climate pseudo scientists is Willis’ “Steel Greenhouse”. There is nothing wrong with the mathematics and as I demonstrated some time ago the results are easy to replicate via empirical experiment –
http://i44.tinypic.com/2n0q72w.jpg
http://i43.tinypic.com/33dwg2g.jpg
http://i43.tinypic.com/2wrlris.jpg
The results of such an experiment show that the addition of the foil layer in chamber 1 slow the cooling of the target plate just like the inner sphere of Willis’ “Steel greenhouse”. Radiative physics shows us that CO2 can absorb and emit IR just like the foil layer in chamber 1. So why have all the climate models failed? There are two critical errors in the radiative greenhouse hypothesis –
1. Climate pseudo scientist made the mistake of calculating the effect of downwelling LWIR over the oceans based on the emissivity of liquid water. Liquid water does absorb LWIR in direct correlation with its emissivity, but only in the first few microns of its skin evaporation layer. This simply trips water molecules into evaporating slightly sooner than they otherwise would. Incident LWIR cannot heat liquid water that is free to evaporatively cool, nor slow its cooling rate. This simple empirical experiment demonstrates the phenomenon –
http://i42.tinypic.com/2h6rsoz.jpg
Run the experiment a second time with a thin film of LDPE floating on the surface of each water sample, restricting evaporative cooling, and observe how different the results are.
2. The second more critical mistake was ignoring the role radiative gases play in tropospheric convective circulation. Essentially the “basic physics” of the “settled science” did not calculate the increase in the speed of tropospheric convective circulation, and thereby mechanical energy transport from the surface, for increasing concentrations of radiative gases. Without radiative cooling at altitude, all strong vertical convective circulation in the Hadley, Ferrel and Polar convective cells would stall, as there would be no subsidence of air masses at altitude. This experiment –
http://i48.tinypic.com/124fry8.jpg
demonstrates the difference in the average temperature of a tall gas column, when heated and cooled at disparate locations at the base (non-radiative atmosphere) and heated at the base and cooled at altitude (radiative atmosphere). Think about this, for the same temperatures and flow rates through the heat exchanger tubes, which gas column runs hotter, and why?
Radiative gases do play a small role in heating the atmosphere by –
1. slowing the cooling of the land surface
2. absorbing and thermalising outgoing surface IR
However their role in cooling the atmosphere far outweighs this by –
1. Driving vertical tropospheric convective circulation, thereby producing the observed lapse rate, reducing average atmospheric temperatures.
2. Driving vertical tropospheric convective circulation, thereby increasing the speed of mechanical energy transport from the surface.
3. Emitting to space not just the energy the atmosphere absorbed by all frequencies of radiation, but all energy acquired from surface conduction and the release of latent heat.
The bottom line is this, radiative gases are not the only heating method for our atmosphere, but they are the only effective cooling mechanism. The net effect of radiative gases is atmospheric cooling at all concentrations above 0.0ppm. Adding radiative gases to the atmosphere will not reduce the atmospheres radiative cooling ability. AGW is a physical impossibility.
@Konrad: yes I still miss your point, for good reasons.
Energy balance must come into play, and consideration must be given to the fact that the earth can only exchange energy with the outer space by mean of electromagnetic radiation (this is not the setup situation of the experiments that you describe).
Over time the radiation received from the sun must be sent away, otherwise the temperature of the surface and of the atmosphere would never stop raising.
The way of sending this energy back is reflection of the incoming light and radiation according to Planck’s law and Stefan Boltzmann equation. With no atmosphere there would be an equilibrium temperature somewhere between 0 K (perfect reflection, no black body) and 279 K (no reflection, all absorption and re-emission by Earth surface as a black body).
With an albedo of 0.3 and an surface emissivity of 0.95 the equilibrium temperature would be 254.8 K (-18.4°C) (average over day-night).
But the earth surface temperature is on average (if anything as an average temperature would exist) around 288 K (15 °C). So something has to have happened, and this is called atmosphere.
The atmosphere is heated first by absorption of the incoming radiation by oxygen and nitrogen in the ultraviolet (UV) range.
What has not been absorbed in the UV range or reflected away is absorbed by the earth surface, clouds, and aerosols. And then, for energy balance reasons, it must be irradiated back in the infrared range (IR).
When a gas containing an IR absorbing substance is irradiated it will absorb energy, therefore, in absence of other heat exchange mechanism, it will heat itself adiabatically with a corresponding temperature increase.
If the concentration of that substance (CO2, water vapour, methane or NOx, …) is higher, then more energy is absorbed, the temperature increases more.
The temperature rise of the atmosphere will continue up to the point where the radiation toward the outer space (from what is called the “top of atmosphere”) will have increased by a quantity equivalent to what was trapped by absorption. A new temperature equilibrium establishes itself.
This is the “primary forcing due to a change of IR absorbing substances in the atmosphere.
Then other feedback mechanisms come into play: by the Planck law itself, water vapour, lapse rate, albedo, and clouds. Overall it is estimated that the sum of these feedbacks is negative, thus dampening the primary forcing. But this is another story, see http://bit.ly/GGZ1r2 .
“Je ne sais pas l’art d’être clair pour qui ne veut pas être attentif.”
Jean-Jacques Rousseau, Du contrat social
Re: Warminsm: Credible Politics, Incredible Science, 11/4/13:
Murphy’s article is a fatally flawed debunking of the monumental fraud of AGW. To be sure, the AGW conjecture is backed by a lot of relative high grade science, but IPCC intersperses the science with nearly a dozen instances of bungled science that intentionally lead to its desired catastrophes. However, the existence of the misnamed greenhouse effect is not one of the bungles.
Murphy’s quote from Wikipedia was sourced an article to the AR4 Glossary, which omitting this bit,
Thus, greenhouse gases trap heat* within the surface-troposphere system. This is called the greenhouse effect. AR4 Annexes, Glossary, p. 946.
to write,
Solar radiation at the frequencies of visible light largely passes through the atmosphere to warm** the planetary surface, which then emits this*** energy at the lower frequencies**** of infrared thermal radiation.
from which Paul Murphy deduced,
gases tend to emit heat at a lower frequency**** than they absorb it*****, and measured net solar radiation does not fully account for near surface air temperatures****** … .
* Heat is energy in transit. It is no longer heat when the flow ceases. Heat cannot be trapped.
** Heat, not radiation, warms. Radiant heat warms, and radiant heat is the net radiation in both directions between objects. The primary heat to Earth is the difference between the Sun’s radiation and Earth’s puny return radiation, the NET radiation. The physics is simple. (1) Heat flows only from a warmer object to a cooler one. (2) Radiation flows both ways between objects. (3) Therefore, radiation is not heat. This is not nit-picking. Nor is it scientific pedantry, or trivia. The book “Slaying the Sky Dragon”, its authors, and its spin-off website, Principia Scientific International, are dedicated to debunking the greenhouse effect based on the unscientific equating of radiation and heat.
*** What Earth absorbs and radiates to space is not “this” solar radiation. All bodies that have a temperature radiate. They radiate in all directions, that radiation intercepting all bodies that lie within the line of sight, whether warmer or cooler. Heat, though, flows only from the warmer object to the cooler object. The statistical atmosphere is cooler than the statistical surface, so for the purposes of climate, heat flows only from the surface to the atmosphere. Earth’s radiation comes from its surface thermal energy, most of which originally happens to have come in the exchange with the Sun.
**** Radiation has color, a characteristic frequency pattern or spectrum, and as the source of the radiation increases, its spectrum shifts to higher frequencies, e.g., in the direction of IR toward UV. Heat is measured with a thermometer. It has no color, no frequency pattern. Because heat flows only from a warmer to a cooler object, radiant heat is always from a higher frequency source to a lower frequency source. That includes the Sun to Earth and Earth’s surface to the atmosphere. Heat is always warming. Absorbed radiation always has the uncertain effect of either warming, or cooling, or neither.
***** Physics identifies four modes of heat transfer: conduction, convection, radiation, and evaporation, but not absorption. Gases absorb radiation, not heat, and in proportion to the product of the incident radiation spectrum and the gas’s absorption spectrum. Gases emit radiation colored according to their temperature. The spectrum absorbed and the spectrum emitted will overlap so that at some colors the incoming radiation will be greater than the outgoing, the reverse holding at other colors.
****** Net solar radiation (heat from the Sun because it’s net) does not account “fully” for surface temperatures, not because the greenhouse model is wrong, but because the surface is simultaneously losing heat to outer space. That heat loss to space is moderated by the greenhouse effect. Whatever its name, and whether accounted for by the confusing back radiation model or the simpler blanket model, increasing the greenhouse effect reduces the heat loss to outer space, tending to increase the surface temperature, all other things being equal. CO2 has a significant absorption spectrum. The warmists got that much right enough for government work, but took at least three giant missteps from that point.
(1) The amount that atmospheric CO2 radiation contributes to the greenhouse effect IPCC calculates as 3.71 W/m^2/ºC using Radiation Transfer in GCMs, and then averaging over a bunch of them. The contribution of GHGs cannot be reliably calculated that way. The global average Radiation Transfer is not the Radiation Transfer of some average atmosphere. And whatever atmospheric model yields the average Radiation Transfer is unknown. IPCC admits that this step is its largest source of error in estimating AGW.
(2) Man’s CO2 emissions are not large enough to scare politicians, so IPCC models those emissions as accumulating in the atmosphere over as much as the entire Industrial Era (since about 1750). At the same time, it models natural CO2 emissions, which are several orders of magnitude greater, as not accumulating. The physics of the uptake of CO2 cannot discriminate between ACO2 and natural CO2 to any significant degree. (IPCC knows the accumulation is manmade CO2 by two fingerprints, both of which are based on chart junk, a topic for another time.)
(3) The increase in temperature over the Industrial Era is due to two effects, the natural glacial cycle over the last half million years, and the recovery from the Little Ice Age. Not enough temperature increase remains for AGW to be scary, so IPCC zeros the natural temperature rises circa 1750, and then attributes all the subsequent natural rise to man.
With these three bits of faux science, IPCC has (1) CO2 causing enough of a greenhouse effect, (2) CO2 emissions accumulating just fast enough, and (3) temperature rising just enough to ring the AGW alarm: man is upsetting Earth’s radiation balance. That upset is causing the surface temperature to rise to catastrophic proportions — not so fast that IPCC results can be validated, but not so distant that action can be deferred. The perfect calm.
But wait! Another assumption lies just behind radiation balance. All other things are never equal. When Kiehl and Trenberth created their radiation budget in 1997, they showed how at the modern surface temperature, 288K (14.9ºC), radiation could be in balance simultaneously at the surface, at the top of the atmosphere, and in the middle. That was a budget, not a prediction. They did not show that those conditions were satisfied at any unique temperature. IPCC tacitly assumes that they did.
(4) IPCC models climate as being drawn to a specific temperature, absent man’s contribution. In scientific terms, IPCC assumed the K&T temperature of 288K was a point of conditional stability. In fact, using K&T’s method, a radiation balance can be shown to exist at any temperature from absolute zero to at least 10K above the present value (0º to 15.9º C vs.14.9º C) just by letting humidity vary.
Keeping AGW going is like any other program adopted by the socialist movement. Obliging people to do something they hadn’t done on their own requires an ever-expanding network of laws and arrests to counteract both the unintended consequences and the new ways free people invent to resist. Telling a scientific fib is analogous, and much like any other lie. Once begun, a seemingly unending number of lies must follow.
AGW needs to be shot down, and the sooner that’s done, the better off the economy and everyone in it will be. But one cannot score a hit by shooting blanks.
Magic et al:
The term “run away greenhouse effect” comes from a 1969 paper by Ingersoll et al on the effects of
water vapor on Venus.. Hence the comment.
Will Pratt says:
November 4, 2013 at 3:21 pm
I always love it when someone pops up to say that my claims have been “debunked” or “demolished” … but somehow they always fail to say exactly who “demolished” my claims, or where.
Will, if you think that any of the science is incorrect that I’ve put forwards in my post entitled “The Steel Greenhouse“, I invite you to QUOTE MY EXACT WORDS FROM THAT POST that you disagree with, and tell us why you disagree.
Because simply waving your hands and uttering the magic phrase “your pseudoscience has long been well and truly demolished” doesn’t make it so … as far as I know, no one has ever demonstrated that any of the things I said in that post were false or violated the laws of thermodynamics.
Nice try at science by assertion, though.
w.
PS—We know the poorly-named “greenhouse effect” exists, inter alia, because of the satellite measurements of upwelling infrared (longwave) radiation. These clearly show that both the clouds and the “greenhouse gases” or GHGs (including water vapor) in the atmosphere absorb and re-radiate energy (the poorly-named “greenhouse effect”), with the net result being that the surface ends up warmer than it would be without the clouds and the GHGs.
We also know the “greenhouse effect” exists because we can measure the downwelling infrared (longwave) radiation at the surface at night. Instead of finding just the radiation from outer space, about 3 W/m2 = almost absolute zero, we find that there is on the order of 300 W/m2 of downwelling radiation at night, and even more if there are clouds.
Note that the blackbody (Stefan-Boltzmann) temperature of the downwelling radiation is at about 0°C. Does this radiation, which is right around freezing, “warm” the earth?
Well … that’s only half a question. The full question is, do GHGs warm the earth compared to what?
Because compared to having no GHGs, the earth ends up much warmer. This is due to having GHGs and clouds which absorb and then re-radiate the outgoing thermal infrared radiation both upwards and downwards. Without the downwelling radiation (~ 300 W/m2), the bitter cold of outer space would freeze the planet solid … so you can term that however you will.
I say the planet with GHGs is much warmer than the planet would be without GHGs.
Whoops. At 7:10 am, I wrote 3.71 W/m^2/ºC when it should have been 3.71 W/m^2 for a doubling of CO2. Apologies.
my truth remains intact, NO insulator ADDS any heat to any system…..NO insulator traps heat…..slowing heat movement does NOT trap it and does NOT cause a build up of extra heat.
Will Pratt, 11/4/13, 3:21 pm
May I offer you a response to Willis Eschenbach’s challenge?
Will, if you think that any of the science is incorrect that I’ve put forwards in my post entitled “The Steel Greenhouse“, I invite you to QUOTE MY EXACT WORDS FROM THAT POST that you disagree with, and tell us why you disagree. W.E., 11/5/13, 8:59 am
Here’s an exact quote, per his request:
In order to maintain its thermal equilibrium*, the whole system must still radiate 235 W/m2 out to space. To do this, the steel shell must warm until it is radiating at 235 watts per square metre. Of course, since a shell has an inside and an outside, it will also radiate 235 watts inward to the planet. The planet is now being heated by 235 W/m2 of energy from the interior, and 235 W/m2 from the shell**. This will warm the planetary surface until it reaches a temperature of 470 watts per square metre. In vacuum conditions as described, this would be a perfect greenhouse***, with no losses of any kind. Figure 1 shows how it works.
* Where is the thermal equilibrium? What is balancing with what? What he means here is Conservation of Energy. If the energy density at the surface of 6,371 km is 235 W/m^2, then at the shell, assuming “a few” means 3, it must be 234.78 W/m^2. Call it 235.
** The shell did not magically become a source of heat equivalent to his model for the interior of the Earth. If the shell is radiating at 235 W/m^2 and with emissivity 1, then it is at 253.7K (-19.4º C), just like the surface of his planet (close enough for .gov work). No heat will flow between the shell and the surface. The surface will not warm. Equivalently, the surface is warmed by conduction from the interior equivalent to 235 W/m^2, and radiates at that density. That outgoing radiation is about the same as the incoming radiation from the sphere. The net is 0. The surface will not be warmed by the shell.
The radiation from the surface will not increase at all, much less to 470 K, the black body value for 301.7K (28.6º C).
*** Eschenbach’s steel shell does not allow radiation to pass through it, absorbing some along the way, and with a temperature drop across its radial thickness. It does not emulate the effects of the gasses in Earth’s atmosphere, formerly called the Callendar Effect, which somebody along the way confused with a greenhouse.
You can add Mr. Eschenbach to my little list of wannabe climatologists who confuse heat and radiation, and so fail to comprehend the Callendar Effect.
Bill Taylor says:
November 5, 2013 at 10:23 am
—————————————————-
Bill, the bad news is that a simple empirical experiment can prove you wrong.
Take two chrome electric kettles and insulate the outer surface of one with bubble wrap and aluminium foil. Switch the power to both kettles on an off to simulate a diurnal cycle. One minute on, one minute off, for a few minutes. The water in the insulated kettle will reach the higher temperature.
The good news is that CO2 is not an insulator. It acts to cool our atmosphere by radiation. Radiative gases in our atmosphere emit to space more than DOUBLE the the energy absorbed by incoming solar and the net flux from the surface combined.
Take two chrome electric kettles and paint the outside of one with matt black paint to improve radiative cooling. Switch the power to both kettles on an off to simulate a diurnal cycle. One minute on, one minute off, for a few minutes. Now the water in the matt black kettle will have the lower temperature.
Michel says:
November 5, 2013 at 6:52 am
———————————————————-
Michel,
I am well aware that the primary energy inputs to our planet are incoming solar radiation and internal geothermal, and the only outgoing energy flux is radiation. Nothing in my post above contradicts this.
What I am arguing is that SB equations in the absence of fluid dynamics, are useless for determining the temperature of our moving fluid oceans and moving gaseous atmosphere.
Applying SB equations to the question of radiative gases in the atmosphere by modelling the planet as a combined land/ocean/gas “thingy” without a diurnal cycle, the movement of fluids parametrised as constant fluxes and constantly fully illuminated with a ¼ power sun is junk science.
To understand the role of radiative gases in our atmosphere, you need to consider land, ocean and atmosphere as separate and in the case of the ocean and atmosphere, mobile.
The primary cooling mechanism for land is conduction to the atmosphere.
The primary cooling mechanism for the ocean is evaporation into the atmosphere.
The primary cooling mechanism for the atmosphere is radiation to space.
The blackbody temperature of a combined land/ocean/gas “thingy” is irrelevant as we don’t live on one. The AGW hypothesis was first proposed as a problem concerning atmospheric temperatures. Empirical experiment shows that the net effect of radiative gases in our atmosphere is cooling at all concentrations above 0.0ppm.
For a planet in where the outgoing radiation is equal to incoming radiation, very different land, ocean and atmospheric temperatures can exist depending on internal energy exchange below the top of the atmosphere. You seem to accept that changes in internal radiative fluxes can effect these temperatures, but ignore that changes in mechanical energy transport can also do this and that radiative gases play a critical role in governing the speed of convective circulation, a mechanical energy transport, below the tropopause.
The AGW hypothesis does not just fail because water vapour feed back is negative, it fails because incident LWIR does not have the same effect over oceans as it does over land and critically, the speed of tropospheric convective circulation increases with increasing concentrations of radiative gases.
Konrad have you tried that experiment? while the heat is on BOTH would reach the same temp…..when the heat is off the insulated pot would stay warm longer but when the heat comes back on they both will again heat to the same temp….also for the experiment to mimic our atmosphere, you need to send the heat THROUGH the insulation which would impede some of it going into the insulated one but would NOT impede the not insulated pot….remove the atmosphere from the earth and we would get HUGE temp swings between day and night……insulation only slows heat movement and nothing in your experiment shows it ADDING any heat to anything….the atmosphere tones down those wild swings by slowing the movement of the energy both incoming and outgoing, BUT again it does NOT add any heat.
Bill Taylor says:
November 5, 2013 at 3:00 pm
——————————————–
Try it with kettles that cannot reach their max temp in 1 minute 😉
Maybe re-read my comment. I am saying that CO2 does not insulate. Like the black paint on the second version of the experiment, CO2 helps the radiative cooling of our atmosphere.
I think it is a mistake to think of CO2 as an insulator since it works more like a reservoir in a store and forward mode. In that case then yes, an atmosphere containing it does trap heat for a time (latency). It is a continuous process similar to a lake except it is filled and drained by a very large number of molecules concurrently rather than by streams. This trapping action is not the same thing as conduction.
And another thing re: other posts – when a molecule’s energy level is raised by absorbing IR radiation the direction in which that energy is later released is dependent upon shape of the molecule on a per-molecule basis, but one has to recognize that all molecules are spinning and gyrating madly and even a population of molecules that radiate asymmetrically will on average radiate equally in all directions.
Nextly, when molecules do radiate they absolutely do not consult with their neighbors to see if the energy state of those molecules is higher or lower – they simply shed the excess energy in what ever directional pattern their geometry describes (CO2 is shaped a bit like an American football so one could presume individually they radiate asymmetrically) and in what ever direction is consistent with the orientation and geometry of the molecule. That means that radiation can strike an object that is at a higher energy level. It cannot be avoided. This effectively makes the entire population behave like an isotropic radiator. In the case of CO2 in our atmosphere, some of that radiation will hit the world. It is left to the characteristics of that object, in some cases, the world, to cope. The result is an increase in surface energy level leading to re-radiation and conduction into the atmosphere where the cycle may repeat. Some may go straight to space.
dp and others ty for the civil tone of your responses…..doesnt the radiation process act as its own regulator meaning as it gets warmer the process of movement speeds up and when cooler the entire process slows down?
Bill Taylor at November 5, 2013 at 4:30 pm
Without going into a lot of Boltzman gymnastics and quantum math, the rate of exchange is related to the level of excitement in the radiating object. Other material properties play a role – space shuttle tiles will behave differently than will frozen CO2, for example, and phase changes affect specific curves of energy exchange ie the freezing point of water.
By example, when designing the Voyager class of space explorers, specifically the energy budget in the RTG and waste heat radiator system, the engineers found they had to allow the heat to build up to a greater level on the spacecraft’s radiating surfaces in order to radiate all the excess heat to space without damaging critical systems (all heat radiates to space, eventually), there being no other means to shed excess energy. It was also important to design the shape of the radiators to prevent back radiation. Sound familiar?
Jeff Glassman says: November 5, 2013 at 10:27 am
“Here’s an exact quote, per his request:”
Although this is an aside, IMHO you’ve missed the ‘Elephant in the room’ from this quote (I’m assuming it ‘is’ accurate):
“This will warm the planetary surface until it reaches a temperature of 470 watts per square metre.”.
‘Temperature’ and ‘power’ are completely ‘incompatible’ metrics. The ‘quote’ is only worthy of diatribe as a form of response!
Best regards, Ray Dart.
Jeff Glassman says:
November 5, 2013 at 10:27 am
Thanks for quoting and explaining, Jeff, much appreciated. By “thermal equilibrium” I mean steady-state. Immediately after a steel shell is added to the system, both the shell and the planet start to warm. After a while, however, they equilibrate and are no longer either warming or cooling, and thus are in steady-state, or what I termed “thermal equilibrium”.
I don’t understand your objection to saying that for a first cut analysis, the area of the surface and the shell are equal. They only differ, as you point out, by a tenth of one percent.
Since the nuclear core is producing 235 W/m2, the system will reach thermal equilibrium (steady state) when the shell is radiating 235 W/m2 to outer space. The shell will continue to warm until it reaches that level (235W/m2), and will warm no further.
The part you seem to be missing is that at steady-state, the shell will also be radiating 235 W/m2 back to the planet. This is added to the 235 W/m2 produced by the nuclear core.
Remember that the shell has twice the surface area as the sphere. As a result, at steady-state, the surface of the planet is radiating at 470 W/m2 over an area A, and the shell is radiating at 235 W/m2 over an area of 2A.
I was not trying to emulate the earth. I was trying to emulate the poorly named “greenhouse effect”. This depends solely on outgoing radiation being absorbed, and then re-radiated, with half of it going out to space and half returning to the surface of the planet. It is immaterial whether the absorber is steel or gas.
Confuse heat and radiation? Where have I done that? Heat is the NET energy flow between two objects. Radiation is the individual energy flow either emitted or absorbed by an object. See? No confusion at all.
Finally, you accuse me of being a “wannabe climatologist”? The scientific journal Nature thought enough of my understanding of climate to peer-review and publish my “Communications Arising” about the climate … and you?
All the best,
w.
Willis;
“the bitter cold of outer space”
Well, only sort of. Outer space is a hard vacuum, meaning there is very little “there” out “there”. A few hydrogen atoms running around (maybe one per cubic foot or so). The rest is empty, void, unpopulated, sans matter, etc. etc.
Temperature is a measurement of the rate at which “things” vibrate. You know; atoms and molecules in various states; solid, liquid, gas, plasma.
By definition with nothing (significant) there, outer space does not have a temperature. It is neither “cold” or “warm”.
If you where foolish enough to put a thermistor in a vacuum chamber and pump it down and report that the temperature of the vacuum is (oh for example; about equal to room temperature) you would be mistakenly reporting the temperature of your thermistor in place of the non-existent temperature of the vacuum.
Check with NASA, they have noticed that objects in outer space (Apollo capsules, Skylab, etc.) have a temperature, but the void of space does not. Really, its true. The very few molecules in the Thermosphere have high temperatures, but there are so few of them you couldn’t warm your coffee there by pausing on the way to the moon.
The 2.3K “background temperature” is actually used to describe the approximate spectral shape of the background cosmic radiation. NOT the temperature of the void of space. It only describes the spectral shape of the radiation, not its “strength” or “magnitude”, etc. In fact, if you look in different directions you find more radiation coming in from some directions than others.
You might want to look up a fellow by the name of Jansky, he figured most of this out a while back. And, he has a physical unit named in his honor.
Talking about the temperature of a vacuum is about the same as discussing the “flavor” of a shape (my, that cube sure looks spicy), or the sound of a color (boy, that purple sure is shrill), or the length of a mass. Nice for a theatrics major, but hardly scientific.
Cheers, Kevin
Willis Eschenbach says: November 5, 2013 at 6:03 pm
With all due respect Willis, you’re confusing individuals that want to learn by offering ‘impossible scenarios’.
To keep calculations to a minimum, let’s assume:
Power generation is 235w and the planet’s surface area (A) is 1m^2.
There’s no problem with the planet, but the ‘shell’ displays a surface area ‘twice’ that of the planet (2A). Thus, when the shell emits 235W/m^2 its ‘power transmission’ is 235w times 2! That’s 470w!
Do you see where this is going? Equilibrium is reached when the planet’s core is at absolute ‘zero’ and the W/m^2 for the shell is halved to 117.5w (117.5W/m^2). The level of energy transmission, per unit area, that the planet’s core is able to maintain at a rate of 235w.
Best regards, Ray Dart.
Konrad, 11/5/13, 1:45 pm, says,
The good news is that CO2 is not an insulator. It acts to cool our atmosphere by radiation.
You might enjoy the abstract of “Novel Lightweight Thermal Insulation Types for the Martian Environment: Using Carbon Dioxide Gas and Aerogel in Lightweight Enclorures”, here
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/18729/1/99-2213.pdf
which says,
In one [type], (10 torr) carbon dioxide of Mars is used as the insulating medium … .
You are correct that CO2 does act to cool our atmosphere by radiation, but it doesn’t cool as much as not being there at all would. For this thought experiment, suppose that the CO2 were replaced with N2, which absorbs little LW radiation.
suricat, 11/5/13, 5:49, points out Eschenbach’s error of quoting “a temperature of 470 Watts per square metre.” I was willing to cut him some slack on that as though we had developed an understanding and no longer needed to spell out “a temperature equivalent to a black body with emissivity 1 radiating at 470 W/m^2”. I think I knew what he meant, and there were more important fish to fry.
Cold and warm are the same thing – concepts to describe the energy level that arrives by radiation. Space has only energy but in any particular point in space (not one which includes the surface of a nearby star) there is very little energy. Taken as a whole the energy of space is the background radiation level which is not very much. Space is considered cold (or hot) as a concept because there is very little background radiation energy, but hot/cold are not the best terms to describe the situation. A passive object set adrift in space will eventually assume the energy level of the background radiation level.
Nature publishes any paper from anyone that meets the criterion at http://www.nature.com/nature/authors/gta/commsarising.html. Being published does not make you a scientist though it is certainly an honorable event. If citizen scientist is legitimized as a term then that is the best you and all of us can be considered but it is largely meaningless and without weight. I suspect nobody within academia would count you, me, or other non-credentialed science writers and so-called citizen scientists among their peers. Woe be to the peer system if it were any other way. It has enough problems as is.
suricat says:
November 5, 2013 at 8:13 pm
Ray, the nuclear reactor at the planet’s core is putting out enough energy to give a surface radiation of 235 W/m2 …
As a result, the system of planet and shell will only be at steady-state when the radiation outward from the shell is 235 W/m2. If it is less, the system will continue to warm …
w.
@Konrad November 5, 2013 at 2:43 pm
Well, it seems to be impossible to instill the concept of energy balance, but I try once more:
What comes from the sun must go away or we would be roasting.
How: by the mechanisme given by Planck’s law and Stefan Boltzmann equation that, so far, have not been invalidated. The outer space is the only heat sink that is available.
By the way: forget geothermal, with 0.082 W m-2 on average it is within the thickness of a splitted hair (0.024% of incoming sun radiation). But this too needs to escape to outer space.
“On ne saurait faire boire un âne, s’il n’a soif.”