Prev  1  2  3  4  

Comments 151 to 182 out of 182:

151. RSVP at 03:11 AM on 31 July, 2010
     doug_bostrom #149 OK. I will make real simple. Put a glass bowl with no water in your microwave oven. Leave it on for 1 minute. See how hot it doesnt get.
     0 0
152. Doug Bostrom at 03:17 AM on 31 July, 2010
     Trying to tune here, RSVP. Are you saying that because a microwave oven's frequency is tuned to dump RF energy into water that if no water is present in the oven the energy will bounce around until it finds its way back to the only thing sympathetic in the room, the magnetron? What's your point?
     0 0
153. Tom Dayton at 03:21 AM on 31 July, 2010
     RSVP, the microwaves are emitted anyway. You can tell because the electricity consumed by the oven is the same as it would be if the bowl contained water.
     0 0
154. RSVP at 03:32 AM on 31 July, 2010
     If watts are consumed in the microwave, its happening in the output amp. If you leave it on too long without a load it will burn out. The waves never launch. If the Universe was only a single star, and there was absolutely nothing upon which it could shine. It could not shine. If you introduced an observer to witness this, you would no longer have a Universe with only a single star.
     0 0
155. Tom Dayton at 03:36 AM on 31 July, 2010
     Okay, I give up, RSVP. You are completely, hopelessly out of touch with reality. Read a physics book, please.
     0 0
156. RSVP at 03:44 AM on 31 July, 2010
     Tom Dayton #154 Or write one, in which case you would probably be reading it. It would not say "by RSVP" of course.
     0 0
157. Tom Dayton at 05:07 AM on 31 July, 2010
     Oh.... I can't let your contention go without response, RSVP, because it isn't even basic physics textbook material--it is microwave oven owner's guide material. An empty microwave oven does not refuse to emit microwaves. Instead, the emitted waves bounce around inside the oven and (potentially) feed back onto the emitter, creating havoc. Just Google "run microwave oven empty." Sheesh.
     0 0
158. Doug Bostrom at 05:42 AM on 31 July, 2010
     That microwave oven remark leads me to believe RSVP is just having us on. Specifically, RSVP knows of impedance matching but somehow cannot grasp the functional difference between thermal emissions and EM as it pertains to tuned circuits? Humoring RSVP I could ask, if a transmitter's antenna is radiating at a peak power of 100kW and the antenna of another transmitter radiating at 50kW on the same frequency is pointed at the first antenna, does the RF from the 2nd antenna "know" that it must not arrive at and resonate with the first antenna? And what's the effect if the phasing is arranged perfectly, or less so? And what's all that got to do with... hang on, -what- was the original topic here? But that's not going to work, because RSVP is going to bring up something else. Next thing I know I'll be talking about the Music of the Spheres or some such, following the Pied Piper of Prevarication. I can't even say "I'm all done with this" because if that were the case I certainly wouldn't be visiting this thread. Oh, what a sticky web RSVP weaves, heh!
     0 0
159. michael sweet at 10:26 AM on 31 July, 2010
     I agree with Doug. I find it very hard to believe that after almost 300 posts on this subject, with at least a dozen independent simple explainations, RSVP really cannot understand the basic physics of the greenhouse effect. I think he/she is having us on and seeing how long s/he can keep us going.
     0 0
160. RSVP at 16:28 PM on 31 July, 2010
     In my Universe, there are no "orphan" photons. It is a tidy Universe. If, for instance, stars radiated without a destination for each photon, there would be a photon clouds collecting in the furthest reaches of space. This of course is not the case. So as it turns out, you all live in my Universe, which from the comments is apparently quite tramatic.
     0 0
161. Doug Bostrom at 21:12 PM on 31 July, 2010
     Almost to "Music of the Spheres," as I predicted. RSVP, have you ever heard of "cosmic microwave background radiation?"
     0 0
162. RSVP at 20:21 PM on 1 August, 2010
     to doug_bostom The Second Law of Thermodynamics states that there can be no net transfer of energy between two bodies at the same temperature. Whether or not the emitter "knows" about the temperature of external objects apriory doesnt really matter. Based on the Second Law, this idea is immaterial and has only caused digression, the obvious implication being that waste heat will have a cancelling affect against GHG back radiation.
     0 0
163. Doug Bostrom at 03:47 AM on 2 August, 2010
     GHGs perform their effect by reducing the rate of loss of energy from an object or system enshrouded in GHGs. Failure to take on board that very basic phenomenon makes further discussion of the topic of AGW entirely pointless. RSVP, if you don't believe in that phenomenon you should consider heading over to Roy Spencer's website where he is actively teaching on the subject right now.
     0 0
164. Phil at 03:50 AM on 2 August, 2010
     If, for instance, stars radiated without a destination for each photon, there would be a photon clouds collecting in the furthest reaches of space. This of course is not the case.at This is sooo funny ! Of course, the clouds of photons that have no destination must be unseeable, because if you can see them then they have a destination (your detector). So you can't say they don't exist !
     0 0
165. johnd at 04:10 AM on 2 August, 2010
     Given the subject at the base of this discussion is electromagnetic radiation, perhaps going back to the very basics of EMR helps. From Wikipedia, "a travelling EM wave incident on an atomic structure induces oscillation in the atoms of that structure, thereby causing them to emit their own EM waves, emissions which alter the impinging wave through interference." It seems that it is irrelevant whether or not that the emitter "knows" the state of the external objects. What is relevant is that the external objects "know" their own state.
     0 0
166. RSVP at 18:30 PM on 2 August, 2010
     doug_bostrom #162 "Failure to take on board that very basic phenomenon makes further discussion of the topic of AGW entirely pointless." What makes this discussion "pointless" can be found elsewhere. The "belief" I have in what I am saying is based on questions Kirchhoff answered many years ago related to radiative equilibrium. Two hot skewers at the same temperatuere when held next to each other will not warm each other. Likewise, waste heat in the atmosphere will impede the effect of GHGs. I have never denied that GHG have meteorological effects, which is very different from what I am saying.
     0 0
167. CBDunkerson at 20:32 PM on 2 August, 2010
     RSVP #165 writes: "Two hot skewers at the same temperatuere when held next to each other will not warm each other." Yes, they will. If you were to take just one of those hot skewers and measure its temperature over time (assuming the air temperature were lower) the results would show the temperature of the skewer falling faster than it would if a second hot skewer were present. You've created a comparison which allows you to deny reality by setting the heat of the two skewers equal to each other... this lets you to pretend that since neither gets hotter than it started out that no heat flows between them, when in reality each emanates heat in all directions (including into the other skewer) but the rate of heat loss from this omnidirectional radiation is greater than the heat gain from the other skewer. Thus, neither 'heats up', but both do 'cool down' more slowly... because heat can and does flow to objects of equal or greater temperature. You insist on believing things about basic physics which are obviously nonsense. There thus seems no hope of ever getting you to accept more complicated realities based on those basic concepts.
     0 0
168. Doug Bostrom at 02:43 AM on 3 August, 2010
     Likewise, waste heat in the atmosphere will impede the effect of GHGs. Following from what?
     0 0
169. RSVP at 03:37 AM on 3 August, 2010
     CBDunkerson #166 You quote me, "Two hot skewers at the same temperatuere when held next to each other will not warm each other." After reading what you wrote, the above is almost the only thing you wrote that is true. The rest goes into refuting things I havent even said (which you call nonsense), but then when you actually do get back to rewording what I did say, "...since neither gets hotter", you are basically agreeing with me. doug_bostrom #167 Let me answer your question with a made up example. Suppose the temperature on the ground nicely heated by the sun is around 30 C. The air temperature say would be 25 C in the absence of anthropogenic GHG. With 100 ppm more GHG, the temperature instead of 25 is 25.5 C. The point here is you will only get the half degree from GHG if local waste heat isnt also taking the temperature up to 26 C as it is in this made up example. Because you are in the city, waste heat is adding 1 full degree Centigrade. Under these conditions the effect of GHG has been clipped by the waste heat. You dont get 26.5 C (1 from waste heat and .5 from CO2). You only get 26 C. I believe this based on what AGW theory itself says.. that GHGs will take temperatures to a new equilibrium. If an external source is adding heat beyond that equilibrium point, GHG will not be allowed to do this (i.e., "impede the effect of GHGs"). Thus answering your question. The other reason I was saying this is based on what I say in #161 with respect to the Second Law of Thermodynamics. Outside of this particular point, the main question is whether global warming is due to GHG vs waste heat. For now it seems according to all the data that GHG overwhelm waste heat on a global average. This may be the case.
     0 0
170. KR at 03:59 AM on 3 August, 2010
     RSVP - Please, please read Roy Spencer's article on Cooler Objects Can Make Warmer Objects Even Warmer Still. If a given amount of energy is going into an object (such as sunlight), cooling to space, it will attain a certain temperature. If a nearby cool object (but warmer than the 3 oK background of space) is present, the heated object will attain a higher temperature. And if you have both GHG and AHF energy going into the atmosphere, the atmosphere will warm more than with only one input - it has to radiate both sources of energy into space. And the ground underneath will warm more as well. There's no 'blocking' of energy involved - that would violate the first law of thermodynamics.
     0 0
171. Doug Bostrom at 04:37 AM on 3 August, 2010
     RSVP, ignoring the nonsense part: Outside of this particular point, the main question is whether global warming is due to GHG vs waste heat. For now it seems according to all the data that GHG overwhelm waste heat on a global average. This may be the case. 169 posts later. Some of us enjoy the journey, others the destination. Maybe even both.
     0 0
172. johnd at 05:21 AM on 3 August, 2010
     CBDunkerson at 20:32 PM, with regards to the 2 hot skewers, what difference would there be in the cooling rate of one hot skewer of mass X compared to two hot skewers each of mass x/2? It appears to me that such comparisons seem to overlook that the mass increases when another object is introduced into the vicinity/equation.
     0 0
173. RSVP at 00:53 AM on 4 August, 2010
     KR #169 "...it has to radiate both sources of energy into space." Now you are basically saying that GHGs are removing waste heat. In other words, CO2 is helping to cool the atmosphere. doug_bostrom #170 I was referring to the numbers, not the theory. Until a theory is disproven, and it is the best thing that you have, then there is nothing wrong with acting on it. This however does not make the theory exempt from examination, and the journey is always a good thing.
     0 0
174. KR at 02:01 AM on 4 August, 2010
     RSVP - "Now you are basically saying that GHGs are removing waste heat. In other words, CO2 is helping to cool the atmosphere." I'm wondering if you are deliberately being obtuse? I'm really having trouble understanding your comments in any other context. "...it has to radiate both sources of energy into space." - If the Earth is in energy equilibrium (averaging over a period of time, it never is on an instantaneous level), it needs to radiate as much energy out to space as it receives from the sun, radioactive decay at the core, AHF, and whatever hot air is generated by climate discussions. Equilibrium means energy in = energy out. The amount of IR radiation emitted from the Earth and the atmosphere scales with the 4th power of temperature. So if there is an increase/decrease of energy going in -> the temperature will rise/fall until the radiation out equals that amount of energy. In addition, GHG's slow the radiation of energy from the Earth and atmosphere (the Earth becomes less efficient at radiating energy at any particular temperature), which means that if GHG's increase -> outgoing radiation decreases -> there is an energy imbalance -> the energy/temperature of the Earth/atmosphere will accumulate/increase until energy in = energy out.
     0 0
175. KR at 02:12 AM on 4 August, 2010
     RSVP - In reference to my previous post, noting that if GHG's increase -> outgoing radiation decreases -> there is an energy imbalance -> the energy/temperature of the Earth/atmosphere will accumulate/increase until energy in = energy out.: The Empirical evidence topic, Figure 2, directly shows the effect of GHS's on the efficiency of the Earth radiating energy to space. This is the energy imbalance I referred to, and leads to energy accumulating until the temperature rises and the sum energy radiated out equals that coming in.
     0 0
176. RSVP at 05:51 AM on 4 August, 2010
     KR #173 I read what you wrote. I agree with everthing you say. However when you talk generally about waste heat, I am not sure where this is coming from specifically. My thought is that N2 and O2 are heated (atmospheric waste heat), or water supply (thermal water pollution). The N2 and O2 (i.e. non-GHGs that make up 97% of air) can either convect to the land, water or ice, or loose their heat via thermo-vibrational translation to GHGs, which in turn emit this energy via IR. In this case, GHG help remove waste heat, but this is not the typical channel (surface to GHG) that is normally modeled.
     0 0
177. RSVP at 05:54 AM on 4 August, 2010
     KR #174 As far a how black bodies work,,, they emit as readily as they absorb, so unless this is established, we shall have difficulty discussing this topic.
     0 0
178. KR at 07:28 AM on 4 August, 2010
     RSVP: Emissivity equals absorptivity for an object in thermal equilibrium. Please read that link - nothing is a perfect black-body (although the ocean is close), emission curves may be smooth (gray-body) or spiky (GHG's, many minerals), but all scale like a theoretic black-body with temperature. If we didn't have any greenhouse gasses in the atmosphere, the Earth would be 33C colder, as the Earth radiated directly to space through the IR transparent atmosphere. The atmosphere would also be colder, as it would only be heated by conduction/convection, no IR. GHG's only warm things up by absorbing IR leaving the planet, sending half the thermal energy they have back at the Earth (radiating energy in an isotropic spherical distribution), instead of letting it go out to space, thereby reducing the total emissivity (emission spectrum) of the Earth. And more GHG's mean more warming. Period, end of story. No cooling, unless you count the stratosphere cooling because all the heat is being kept close to the surface of the earth. You have failed to do the most elementary reading on greenhouse gasses or emissivity, thrown around red herrings such as the 'double-slit experiment', made incorrect claims about energy cancellation in microwaves, ignored the measured energy flows of the Earth/atmosphere system to argue for convection, and not understood thermal diffusion in a gas. If you are not just trying to crank people up, you are certainly failing to understand the information we have pointed you towards. I think this will be my last post on this topic.
     0 0
179. KR at 12:51 PM on 4 August, 2010
     Some more explanation about black-body and real-life object emissivity and absorptivity, greenhouse effect, etc.: Every material has an absorption spectra. The emission spectra is identical in distribution (peaks, valleys, etc.), but the emission spectra is scaled by the temperature of the material. This scaling is proportional to the 4th power of the temperature. A "black-body", a theoretic 100% emissive material, has well defined spectral curves at different temperatures. Actual materials have spectra that will always be <= the black body energy at any wavelength. "Gray-body" materials (liquid water is a good example) come close to black-body spectra, while others like C02 have spiky spectra (always less than the black-body spectra for equivalent temperatures). When a material is in radiative equilibrium (assuming no other inputs), it's at a temperature where the emission spectra is scaled identically by temperature to the absorption spectra, and hence the same amount of radiative energy is emitted as is received - no energy changes, no temperature changes. Materials with low absorptivity at thermal wavelengths (like N2, O2, as they are too small and have no dipole moments) are essentially transparent (gasses/liquids) or reflective (solids) to IR - they do not heat or cool well through thermal radiation. A silver plate, for example, won't heat up in daylight very well - low absorptivity in that spectra. CO2, CH4, and H20, on the other hand, readily absorb at IR wavelengths. When they radiate (at a rate dependent on their temperature) they do so in an incoherent, isotropic fashion - random photons in random (spherically distributed) directions. In the greenhouse effect, an atmosphere with GHG's present will have surface IR absorbed by the GHG's, heating them. The GHG's will radiate spherically, which means half the emissivity spectra goes back to the surface. From outside the atmosphere, half the photons at the emitted wavelengths don't come out of the atmosphere. This changes the emissivity spectra of the planet, giving a smaller integrated spectra (and energy) emitted at any particular temperature. If the emissivity spectra is changed (absorption remaining the same, as daylight is 99% not absorbed by GHG's), energy emission changes as well, and there is an energy imbalance. Energy will accumulate or disperse, temperatures will change, until the atmosphere radiates the same integrated energy as it receives.
     0 0
180. RSVP at 20:57 PM on 4 August, 2010
     KR 177, 178 I have read both 177 and 178 twice now. Didnt see waste heat mentioned once, which is the topic of this thread. You say I have not, "...understood thermal diffusion in a gas". I assume you are referring to that which GHGs impart to non-GHGs. I have no problem with that idea. However, if you inject heat directly into non-GHGs (i.e. introduce waste heat), I assume it will work the other way around, in which case, non-GHG heat will impart thermally to GHGs which will in turn radiate heat (up and down) as you say. That which is going up, is cooling, and yet you say, "And more GHG's mean more warming. Period, end of story. No cooling,.." This last sentence may be true for radiation generated from the surface, but does not seem to apply for heat injected into the atmosphere. You dont have to admit you are wrong. I may even be wrong in the long run, but I dont think the idea on face value has no merit as you would like to make this seem (given you tone and remarks).
     0 0
181. Tom Dayton at 23:36 PM on 4 August, 2010
     RSVP, there are GHG molecules above and below other GHG molecules. As each molecule radiates up, those upper molecules intercept that radiation. Then those recipient molecules themselves radiate up and down. There are many, many such layers. The effect is radiation being "trapped" within those layers. Except at the top of the atmosphere, where there are no other GHG molecules above the topmost ones, so the extra radiation of the topmost ones does not get intercepted. So the topmost ones cool.
     0 0
182. chris at 23:54 PM on 4 August, 2010
     It's worth supplementing Tom's response just above since he very nicely gets to the root of the greenhouse effect. As Tom indicates, thermal energy is radiated to space from the upper regions of the atmosphere (specifically those regions of space at a temperature appropriate to balance the incoming solar radiation at a "temperature near 255K). Clearly the layers of the atmosphere right down to the Earth's surface are wamer than this (can be determined by the lapse rate). Now we add more greenhouse gas. At any particular height in the atmosphere the radiation of LWIR to space is less efficient since there is more higher altitude CO2 to absorb the LWIR. With more greenhouse gas, the emission of LWIR to space must necessarily occur from a higher altitude on average. However to maintain thermal equilibrium with incoming solar irradiation, the temperature of the layers from which LWIR is emitted to space must be the same as before. In other words those layers must warm up to the previous temperature (i.e. without the addition of greenhouse gas). All the layers below (right down to the earth surface) warm up. That's the greenhouse effect.
     0 0
183. RSVP at 14:21 PM on 5 August, 2010
     180, 181 Strange. Given the model as described in 180 and 181, it would seem the more GHG, the greater the pathway for IR. Such that the more GHG, the more cooling. However, it doesnt work like that, at least as described here: http://en.wikipedia.org/wiki/Greenhouse_effect Wikipedia "The greenhouse effect is a process by which radiative energy leaving a planetary surface is absorbed by some atmospheric gases, called greenhouse gases. "
     0 0
184. Tom Dayton at 15:26 PM on 5 August, 2010
     RSVP, the GHG molecules radiate spherically, not just up. So half of the radiation goes down, thereby not cooling whatever is below, because the "cooling" that is the sole point of this discussion is cooling of the entire Earth, which can happen only by radiation going up all the way to space. Of the half of the radiation that goes up from a GHG molecule, nearly all of it fails to get straight to space, because it runs into other GHG molecules. And so on. So the "greater pathway for IR" is not a straight pathway up to space. Instead it is a convoluted pathway that has far more segments pointing down and sideways than up.
     0 0
185. KR at 15:39 PM on 5 August, 2010
     RSVP - quite true, given that GHG's radiate well in IR, you would think they cool things. However, if you consider that GHG's intercept IR quite well in their absorption bands, and half the IR radiation from the GHG's is back to the ground, the sum effect is to decrease the emissivity of the planet to space. GHG's are decent IR radiators, but not as good (i.e., broadband) as dirt and water, and bounce half the energy back. You end up with more radiation from the top of the atmosphere, less from the surface, but a total of less energy radiated overall. Given a fixed energy input, an object with low emissivity (radiating poorly) will stabilize to a higher temperature than an object with high emissivity (radiates easily). It will stabilize at a temperature where the emitted energy equals the absorbed (input) energy. I remember many years ago reading about radiant heaters - electric panels to heat rooms of your house. One of the manufacturers did a sand painting on the surface of the panel to make it look prettier. The increased surface area increased the emissivity/sq. ft. of panel, and the heater was much more efficient - more surface area/sq. ft. better chance to emit IR. Changes in total emissivity can have a big effect.
     0 0
186. johnd at 22:08 PM on 5 August, 2010
     When considering IR being intercepted by GHG's one should also consider IR being intercepted by clouds. Clouds are condensed droplets or frozen ice crystals formed after water vapour has liberated all heat energy carried from the surface aloft, and so given their state, and the fact that they provide about 2/3 coverage over the earths surface, are not only well placed to intercept IR, or waste heat, but that absorption provides the trigger and the means for that IR, or waste heat, to be returned to the earth's surface along with any more it absorbs on the way down.
     0 0
187. chris at 04:10 AM on 6 August, 2010
     RSVP at 14:21 PM on 5 August, 2010 Not strange RSVP, so long as one doesn't leave out both the absorptive properties of greenhouse gases, and their spherically-averaged radiative properties. Then the Wikipedia and our explanations are entirely compatible. A comparison of a "naked Earth", with an Earth surrounded by an atmosphere containing greenhouse gases might help to overcome your apparent paradox: (i) a "naked earth" (no atmospheric greenhouse gas). The solar radiation warms the surface which radiates LWIR. Since there is no atmospheric absorption of LWIR this emitted radiation travels freely to space. Thus the maintenance of radiative equilibrium (with incoming solar) is achieved by emission from the surface. The flux of LWIR required to balance the incoming solar flux is reached by a surface temperature of around 255K (taking into account earth surface albedo). That's the surface temperature of a "naked earth". (ii) Now we add LWIR-absorbing atmospheric gases which captures the LWIR and either reradiates (spherical distribution) or transmits the vibrational energy to other atmospheric gases by molecular collisions, warming these. Clearly for radiative equilibrium to be maintained the radiative flux must still balance the incoming solar radiation. However the photons radiated to space to achieve this are now emitted from an altitude that is higher, on average, than the surface, and thus colder. In order to generate sufficient radiative flux these regions must warm up. All the atmospheric layers right down to the surface warm up too. Everyone on the surface is warm and happy!
     0 0
188. RSVP at 17:58 PM on 6 August, 2010
     KR #184 (...et. all) "You end up with more radiation from the top of the atmosphere, less from the surface, but a total of less energy radiated overall." It is not clear to me why the atmosphere's vertical temperature profile should affect the overall energy discharge. In my mind, there is on the one hand a) an energy discharge associated with surface-to-space flux, and on the other hand b) (generally independent of this statistically) flux associated with GHGs-to-space. If the profile of temperature changes slightly raising temperatures in the lower atmosphere (i.e., the green house effect), how does this affect net upward flux of a or b? Unless there is a particular reason, to me it seems, the overall net energy released is the same. There is no accumulation of energy. If however, you add heat (i.e., waste heat), now you have something very tangibly added to the system. (i.e., energy cannot be created or destroyed etc.). And it is being added day in, day out... even at night. I think KRs sentence is inaccurately expressed, and it is not a big deal, we all make mistakes. In fact, it has been helpful to point out... 1) GHG DO increase temperatures in the lower atmosphere. 2) GHG DO NOT imply overall energy accumulation from the Sun, but yes, a change in energy storage distribution. 3) Waste heat DOES imply an increase in the net energy being stored and therefore is a big environmental problem. The outward flux never changes, so waste energy can only accumulate. 4) Perhaps the only solution is increasing the Earths albedo. PS This is only my humble opinion.
     0 0
189. KR at 00:42 AM on 7 August, 2010
     RSVP - Aha! I believe I see the (perceived) issue. First of all, the presence of GHG's reduce the surface emission of IR where they absorb. This is partially replaced by thermal emission of the GHG's, but only partially - only half the IR emitted by the GHG's will escape to space - the rest heads back down to the surface. You can see that in thermal spectra for the Earth from space - where GHG's are fully saturated the IR at that wavelength is half the black-body value. So the rate of Earth's energy loss at a particular temperature (integrated spectrum of IR) DECREASES with increasing GHG concentration. This is crucial to the discussion. I will therefore completely disagree with on your statement: GHG DO NOT imply overall energy accumulation from the Sun, but yes, a change in energy storage distribution. No! GHG's directly cause energy accumulation! An analogy: You have a water tank with an open top (Earth/water/atmosphere energy in joules). You pour water in at a steady rate (Sunlight, waste heat, internet discussion, whatever). At the bottom of the tank is a drainpipe (radiation to space). The water level (temperature) is set by the pressure required to push as much water out through the drainpipe as is pouring in the top - if the water level rises, it drains faster, if it drops, it drains slower, but that tank will reach equilibrium with output flow = input flow. For fun we can set the output rate to scale with the 4th power of water level. Now throw in some leaves (GHG's blocking IR) partially clogging the drainpipe, reducing the outgoing flow. What happens? Water doesn't leave as fast as it's entering. And guess what - the water level in the tank rises (accumulating). It rises until the output rate equals the (unchanged) input rate; the temperature rises. Rising GHG's induce an energy accumulation - Output energy at a particular temperature decreases, output is less than input, energy accumulates, temps rise causing more output energy, until we're back at equilibrium with the output energy at the new temperature equals what's coming in. Warmer Earth, warmer water, warmer atmosphere, more energy present.
     0 0
190. Berényi Péter at 01:31 AM on 7 August, 2010
     #188 KR at 00:42 AM on 7 August, 2010 where GHG's are fully saturated the IR at that wavelength is half the black-body value What do you mean by "fully saturated"? As pressure decreases steadily as you go up, there is always a height from where radiation can escape to space, that is, above it air gets "transparent". With current CO₂ levels at 15 μm it is about 22 km above the surface. At that altitude the higher you go the higher temperature gets. Therefore putting more carbon dioxide into the system increases the effective radiation temperature at that frequency. I can't understand your "half the black-body value" allusion either. Half the black body value for what temperature?
     0 0
191. KR at 02:37 AM on 7 August, 2010
     BP - I found the graph I was looking for. See Has the greenhouse effect been falsified?, figure 1., where the CO2 bands are sending ~1/2 their IR to space, 1/2 back down. Without the GHG blocking the spectra would closely follow the black-body curve at ~267K, or it would until things cooled off. I used "fully saturated" poorly in my posting - what I intended should have been the much wordier "for those wavelengths where there's enough GHG in the atmospheric column to essentially absorb direct ground radiation before it gets out to space uninterrupted, thus preventing direct radiation and only showing spherically distributed thermal radiation from the GHG". Because I, well, thought that was pretty wordy...
     0 0
192. KR at 02:47 AM on 7 August, 2010
     The 'saturation', or rather the GHG emission only range I was looking at on Has the greenhouse effect been falsified?, Figure 1., is the 16-14 micrometer band.
     0 0
193. RSVP at 03:42 AM on 7 August, 2010
     KR 188 "Water doesn't leave as fast as it's entering." You yourself acknowledge that energy radiates as T to the fourth. So if the surface warms, it should radiate harder. In the analogy, the leaves slow drainage and this would be a problem if the inflow of water remained the same, but as surface radiation increases with T^4, the analogy seems to break down. Even in the analogy, you could have said that outflow increasing due to increased water pressure, but you didnt. I can also make up analogies... imagine two 50 gallon barrels that are filled with 25 gallons of brackish water every morning for one month. At the bottom of each barrel there are two distinct filters. The first has coursely ground activated charcoal, and the second a much finer grid of activated charcoal. Both are allowed to drain during the day. Everyday, by six in the evening, the first one is empty, whereas the second one takes until midnight. Examining the filters, we see that the distribution of dirt in the first is spread thoughtout the filter, whereas in the second most of the dirt remains in the upper layers of the filter. In this analogy, you can see how the density of the filter (GHG concentration) slows the flow, but that the total energy is release in both cases (no accumulation of energy due to filters). The notable difference is the guck profile in the filters (temperature profile in the atmosphere). So I am allowing for warmer temperatures in the lower atmosphere due to GHGs but I am saying that it must be made up for a cooler upper atmosphere given that the net heat flux is constant. Of course higher temperatures at the surface can mess up the biosphere, and melt ice etc., but in terms of energy storage, it is not clear to what extent this is happening, but even you have said that radiation goes as T^4, so a warmer surface would induce more radiation. We dont want to forget about waste heat... During the night, it rains during the last two weeks of the experiment, but no one realizes it. It is noticed that the barrels take longer to drain. In fact during the last week of the month, they are finding water still draining in the wee hours of the morning. Those conducting the experiment are certain that it is due to the accumulated muck.
     0 0
194. VoltairesDistantCousin at 03:44 AM on 7 August, 2010

     In comment #189, it was asserted that

     "...With current CO2 levels at 15 μm it is about 22 km above the surface. At that altitude the higher you go the higher temperature gets. Therefore putting more carbon dioxide into the system increases the effective radiation temperature at that frequency."

     Specifically, the poster asserts that the temperature increases with altitude at 22km. This is incorrect. At 22 km, we would still be in the stratosphere, a layer of the atmosphere in which temperature decreases with altitude. It is only when we reach the thermosphere, above about 95 km that we see temperatures rising with altitude. However, in the thermosphere, the air is so sparse as to be nearly transparent to exiting infrared photons.

     Has the level of rational debate degenerated so much that we are having skirmishes over basic facts such as this?

     0 0
195. KR at 04:43 AM on 7 August, 2010
     I'm afraid, RSVP, that you are not following the analogy I presented. I DID state that the water pressure drove the outflow rate, with "if the water level rises, it drains faster, if it drops, it drains slower...For fun we can set the output rate to scale with the 4th power of water level". Your analogy of two buckets makes no sense - as has been covered before (repeatedly, by several people), there is only one bucket, one set of energy. It really doesn't matter if the AHF energy comes in fast, slow, through convection, radiation, conduction - the AHF rate is 0.028w/m^2, and it ends up depositing that energy into the mass of the Earth/water/atmosphere at 0.028w/m^2, or 0.028 joules/sec/m^2. That's a rate of energy input to the total Earth/water/air energy. Adding AHF to sunlight, in the analogy I gave, means adding to the water inflow. If 100 gallons per minute are pouring in from the sun, and you add 1 gpm of AHF, well then the water level/pressure (and by analogy temperature) will rise a bit until the output increases to match. If you reduce the outflow rate at the current water level to 90 gpm, water level and pressure will rise until the outflow is again 100 (or 101 with AGH) gpm. Again - there is only one system receiving energy; the sum of Earth+water+atmosphere. There is only one output for that energy, radiation to space. And changes in either the rate of input or output will change the radiative equilibrium temperature of the system. If you cannot understand that, and continue to insist that AHF somehow acts differently than solar energy (does it somehow produce a different flavor of joules - chocolate, perhaps?), then you have a conceptual issue I cannot help you with.
     0 0
196. Ned at 04:44 AM on 7 August, 2010
     VoltairesDistantCousin: BP was right and your "correction" of him is wrong. Temperature decreases with altitude in the troposphere, increases in the stratosphere, decreases in the mesosphere, and increases again in the thermosphere:
     0 0
197. Ned at 05:18 AM on 7 August, 2010
     That said, I'm not sure why BP refers to emissions at 15 μm. Adding CO2 to the atmosphere causes relatively little additional reduction in OLR at 15 μm, and thus relatively little change in the height at which emission occurs. Most of the change from increased CO2 is at 13-14 and 16-17 μm, and overall it's going to lower the effective radiating temperature rather than raise it.
     0 0
198. VoltairesDistantCousin at 07:13 AM on 7 August, 2010
     Ned, BP: My apologies. Temperature does increase in the stratosphere due, I think to ozone's absorption of UV radiation. I was too quick with my correction. I will do more research before posting further.
     0 0
199. Doug Bostrom at 08:25 AM on 7 August, 2010
     I will do more research before posting further. A contrite acknowledgment from VoltairesDistantCousin that ought to be exemplary, could well stand some emulation. Has the level of rational debate degenerated so much that we are having skirmishes over basic facts such as this? Actually it's much worse than you may think. Read through ~200 comments and you'll get the picture.
     0 0
200. RSVP at 21:43 PM on 7 August, 2010
     KR 194 "If you cannot understand that, and continue to insist that AHF somehow acts differently than solar energy (does it somehow produce a different flavor of joules - chocolate, perhaps?), then you have a conceptual issue I cannot help you with. " The idea of chocolate flavored joules is sweet (no pun intended). Before I go on, sorry for not realizing that you did tie water level to radiative power in your analogy. My apologies. Aside, my two buckets (192) is not a comparison between waste heat with GHG heat as you seem to imply. The point of having two buckets had to do with comparing water discharge rate and silt profiles for two different types of filters. The filters represent effects of higher and lower CO2 concentration. It is a crude analogy only for purposes of focusing on temperature profiles which as per Ned 195 seems to be mapped out fairly well. That said, I am not convinced that there are not "chocolate" joules so to speak. For instance, wind chill factor can make a lot of difference to heat loss... its not that the joules are different, its that they are being transferred at a higher rate due to a moving fluid and evaporation. Likewise, N2 and O2 emissivity being much lower means that these gases radiate much slower than CO2. I have yet to see anyone even after 200 comments (i.e., doug_bostrom #198) address this question squarely. After saying this, of course, someone will now come up with some hoaky comment to simply distract attention from this issue,... please dont make me right (again). Back to "chocolate" flavored joules... What am I talking about? In the same way that wind chill factor affects cooling, radiative emissivity affects the rate for a grey body to cool. And given that N2 and O2 emissivity is much lower than that of CO2, a relationship must exist relating the theoretical waste heat value and apply a E(CO2)/E(N2) or E(CO2)/E(O2) factor and end up with a effective (chocolate) warming factor. The fact that no one has investigated this, does not make this possibility any less real. And from my point of view, in your not wanting in internalize this idea, I could just as easily say that, "you have a conceptual issue I cannot help you with."
     0 0

Prev  1  2  3  4  

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.