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Throwing Stones at the Greenhouse Effect

Posted on 18 October 2010 by gpwayne

Some climate change skeptics dispute the so-called ‘greenhouse effect’, which keeps the surface temperature of the Earth approximately 30 degrees C warmer than it would be if there were no greenhouse gases in the atmosphere. In other words, without the greenhouse effect, the Earth would be largely uninhabitable.

How do we know for sure this effect is real? The principle is demonstrated through basic physics, because a bare rock orbiting the sun at the distance of the Earth should be far colder than the Earth actually is. The explanation for this observation was based on the work of John Tyndall, who discovered in 1859 that several gases, including carbon dioxide and water vapour, could trap heat. This was the first evidence for what we know now as greenhouse gases. Then, towards the end of the same century, a Swedish scientist named Svante Arrhenius proved the relationship between greenhouse gas concentrations and surface temperatures.

Empirical Evidence for the Greenhouse Effect

We only have to look to our moon for evidence of what the Earth might be like without an atmosphere that sustained the greenhouse effect. While the moon’s surface reaches 130 degrees C in direct sunlight at the equator (266 degrees F), when the sun ‘goes down’ on the moon, the temperature drops almost immediately, and plunges in several hours down to minus 110 degrees C (-166F).

Since the moon is virtually the same distance from the sun as we are, it is reasonable to ask why at night the Earth doesn’t get as cold as the moon. The answer is that, unlike the Earth, the moon has no water vapour or other greenhouse gases, because of course it has no atmosphere at all. Without our protective atmosphere and the greenhouse effect, the Earth would be as barren as our lifeless moon; without the heat trapped overnight in the atmosphere (and in the ground and oceans) our nights would be so cold that few plants or animals could survive even a single one.

The most conclusive evidence for the greenhouse effect – and the role CO2 plays – can be seen in data from the surface and from satellites. By comparing the Sun’s heat reaching the Earth with the heat leaving it, we can see that less long-wave radiation (heat) is leaving than arriving (and since the 1970s, that less and less radiation is leaving the Earth, as CO2 and equivalents build up). Since all radiation is measured by its wavelength, we can also see that the radiation being trapped in the atmosphere is at the same wavelengths as those absorbed by greenhouse gases.

Disputing that the greenhouse effect is real is to attempt to discredit centuries of science, laws of physics and direct observation. Without the greenhouse effect, we would not even be here to argue about it.

This post is the Basic Version (written by Graham Wayne) of the skeptic argument "The greenhouse effect has been falsified". It's worth bringing up that the Intermediate Version was written by Chris Ho-Stuart, co-author of the peer-reviewed paper Comment on "Falsification of the atmospheric CO2 Greenhouse Effects within the frame of physics" (Halpern et al 2010).

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Comments 51 to 98 out of 98:

  1. e at 08:21 It is totally hypothetical, o course all gases/matter emit and absorb LW, some a lot better than others. Nothing wrong with pondering. I do take issue with unphysical descriptions when they arnt stipulated as such myself, as i have further up the thread.
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  2. Something I've noted in these discussions, where the Earth is noted to be 30+ degrees C warmer than it would be without greenhouse gases, is that there is an implied "...all other things unchanged" in the thought experiment. Yes, without greenhouse gases, the oceans would freeze, increasing the planetary albedo, making the surface considerably colder. Yes, the lapse rate would be purely convective/conductive, rather than largely driven by IR and latent heat. So the 30+ degrees is likely a considerable underestimate. But the take-home point of this thought experiment is simply that: It would be a lot colder without greenhouse gases. The radiative greenhouse effect is real, observed, and part of the current climate.
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  3. Joe Blog, Ah ok, sorry I didn't see the earlier post. I don't think RSVP gets this concept though: "This air has no GHG, so it cannot radiate heat." "And afterwards, without any "green house gas", it would be interesting to know how exactly it should emit heat???"
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  4. e at 08:44 Ohh, i see. I thought we were talking thought experiments.
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  5. e "The atmosphere will continue emitting radiation into space whether GHG's are there or not." Either this is true or the term GHG is meaningless. Take your pick.
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  6. RSVP - Without any GHG's present (i.e., no gases that absorb/emit at IR wavelengths) the atmosphere would be strictly warmed by conduction/convection, plus latent heat if anything remained unfrozen, from the surface. There would be a very different lapse rate, and no IR from the atmosphere. But: This is a thought experiment. It's clear from the thought experiment that the planet is much warmer with than without GHG's. And that's the point of the thought experiment. The radiative greenhouse effect is real, observed, and part of the current condition of the Earth. We now return to other discussions, other threads, of changes in the level of the greenhouse effect; and the causes of recent global warming. :)
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  7. RSVP, With the time you've spent on this site I'm surprised you don't seem to understand the basics of how the greenhouse effect works. How can you take such a strong position on a topic without understanding how it works? Let me take a stab at explaining: First off, all matter above absolute zero emits some thermal radiation. The ability to emit thermal radiation alone is NOT what makes GHG's special. The key is that although all matter emits thermal radiation, different molecules may absorb and emit specific frequencies of radiation more readily than other frequencies. In the case of GHG's, they readily absorb radiation in the infrared spectrum, while being nearly transparent to radiation in the visible and UV spectrum. Radiation coming from the sun is primarily in the visible and UV spectrum. Meanwhile, radiation emitted by the earth's surface is primarily in the infrared spectrum. So here's what happens: the visible/UV spectrum radiation coming to the earth from the sun mostly passes through the atmosphere without being absorbed by GHG's. The surface of the earth absorbs this radiation and heats up, and then emits radiation in the infrared spectrum back up towards the atmosphere. This energy is now readily absorbed by GHG's, which is subsequently radiated back out in all directions. The result is that most of the energy coming in is unimpeded, while energy going out is partly radiated back down to the surface. This creates an insulating effect which causes the earth to retain more heat than it would without GHG's. The remaining gases in the atmosphere still emit thermal radiation, just not as readily as GHG's, and more importantly, they do not absorb infrared radiation as readily. If we removed GHG's from the atmosphere, these remaining gases would continue emitting radiation just as they do today. The difference is the extra warming provided by GHG's would be gone, so overall the planet would be much colder. For a good basic overview of these topics, I recommend the following: Thermal Radiation Greenhouse effect
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  8. RSVP at 09:09 AM O2 and N2 are largely transparent to terrestrial radiation(O2 is semi opaque to UV, and this is how O3 is formed, through the break down of O2 to atomic O and the free O combining with a another O2 molecule to form O3, And O3 is very opaque to UV and thus the reason the stratospheres T profile is reversed, due to heating from above from UV, and radiative cooling from below through co2) The only way energy has to leave our planet, is through radiation, truth is convection transports more energy in the lower troposphere than radiation, due to the fact that it already is at those pressures very opaque to LW, but the limiting factor causing the temperature profile in the troposphere, is the altitude where energy can escape to space. Now the reason why its at higher altitudes that it can escape to space/the atmosphere is more transparent, is due to the fact that there is less pressure, less molecules in a given area, so with less opaque gases in a given area, the further the probability of a photon traveling before it is absorbed. Now if you increase the ratio of opaque gases in the atmosphere, you raise the altitude at which energy can escape to space, just by the simple fact, that it increases the amount of molecules in a given area for a given pressure. Increasing the probability of a photon being absorbed for a given distance, at a given pressure. Thus raising the height at which energy can escape from the lower atmosphere to space, and raising the surface T by the need for the T gradient to transport the energy to this higher altitude... in a nut shell.
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  9. Roger #20: Why are nearly 75% of Americans, American news media, and American politicians deniers? Do you have a link for that stat, by any chance? I'm curious to see what "nearly" means, in this context.
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  10. @Phila "You've managed to cram a surprising number of logical errors into a very brief comment. First, the Bible is not a reliable guide to what "creationists" believe, since different creationists interpret it in very different ways. Second, Genesis 9:13 has nothing to do with climate science, obviously. Third, modern creationists -- of the activist type, especially -- have had a pretty strong tendency to deny AGW." I'm not talking about AGW rather the green house effect which is the topic of this discussion. Genesis (9:13 in particular) does have a lot to do with climate science unless you arbitrarily throw out data points for no other reason than you don't like the source. It is a clear reference to climate change and global warming. I'll leave it to you to figure out why. Don't mistake logic for presuppositions. We don't share those, methinks.
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  11. RSVP, It is a waste of my time to reply to your posts. Others have covered the material, I liked e at 49 especially. I suggest the moderator delete future posts to keep this thread from becoming another waste heat thread trying to explain to you the basics of heat transfer in the atmosphere. You have extraordinarily strong comments for someone who understand so little science.
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  12. @Bibliovermis "What relevance does...have to global warming, much less to a discussion about the greenhouse effect? Did you just type "clouds" into a bible search engine & post the first entry it returned?" Actually it's one of those verses that hangs around in my memory banks. Been aware of it's relevance for more than 40 years. I've actually read the Bible cover to cover a few times. I'll leave it to you to figure out it's relevance, but it is very relevant. There are a number of verses in Genesis that discuss climate. They don't necessarily fit into commonly held theories. I was reading this quote from the the first link in the link you posted: "'The influence of so-called greenhouse gases on near-surface temperature - is not yet absolutely proven. In other words, there is as yet no incontrovertible proof either of the greenhouse effect, or its connection with alleged global warming." Heinz Thieme This quote is not from Marohasy. In context the quote is using the term green house effect for the specific effects of the so called green house gases, not the green house effect of the atmosphere as a whole.
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    Moderator Response: Discussions of biblical interpretations are not really appropriate for this blog. Please keep comments on-topic and relevant to the science.
  13. "the quote is using the term green house effect for the specific effects of the so called green house gases, not the green house effect of the atmosphere as a whole." Total nonsense. The atmosphere can not have a greenhouse effect unless GH gases are part of it. This thread is going nowhere fast.
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  14. It is relevant, John. The problem with the Bible, though, is determining with any degree of precision just when the relevant parts were written. The stories that make up the Bible--even those of the NT--were developed over centuries--perhaps longer. The Jesus stories may be imported from other, earlier cultures (Egypt, Horus--that sort of thing). If you question tree ring proxies, you shouldn't be moving toward the Bible as a proxy. RSVP, if any climatologist had made your claims on this thread, even the folks over at WUwT would be ROFL (ABSTTN - and blowing soda through their noses). Seriously, take a little time off and study radiative transfer and what happens to incoming solar radiation when it hits the various surfaces of the earth system.
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  15. Sorry, but im going to have to reiterate my objection to this part of the last paragraph: "The most conclusive evidence for the greenhouse effect – and the role CO2 plays – can be seen in data from the surface and from satellites. By comparing the Sun’s heat reaching the Earth with the heat leaving it, we can see that less long-wave radiation (heat) is leaving than arriving" This is unphysical, no two ways about it, if it were true we would be heading for the Temperature of the surface of the sun. It is disingenuous to try and cure a misconception, with another misconception. By comparing incoming energy, vrs outgoing,vrs thermal capacity of the surface, you can determine that the average T should be -18C... But its not, that is the proof of the GHE. The fact that the average T is 15C. This 33C worth of energy in transit in the atmosphere is the proof.
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  16. "This 33C worth of energy in transit in the atmosphere is the proof. " This average increase of 33C at the surface as a result of energy in transit through the lower atmosphere is the proof... being pedantic again.
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  17. Joe, I think you make a valid point, but consider that this post is meant as a "basic" version of the argument. Technically speaking, the short term decrease in outgoing radiation is evidence of an enhanced greenhouse effect, not a greenhouse effect in general. It's an important distinction to make, but I think it's a bit too pedantic for a basic version of the post. If you take a look at the intermediate version of this post, you will notice that this distinction is spelled out more explicitly.
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  18. Joe Blog - Actually, having less energy leaving than arriving is exactly what is happening. The various feedbacks and systems (ocean temperatures, in particular) have a time lag to changes in forcings, and are still approaching equilibrium. While that is occurring, there will be a net imbalance at the top of the atmosphere. The climate doesn't react instantly - there's always a lag to respond to forcing changes. And positive feedback doesn't indicate a runaway situation unless the gain is >1, as has been repeated discussed here.
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  19. @DSL Very good point. "Seriously, take a little time off and study radiative transfer and what happens to incoming solar radiation when it hits the various surfaces of the earth system." The albedo of the ocean is microscopic when compared to the land or clouds. In other words the ocean absorbs almost all the radiation that hits it. So what keeps it so cool? Water is the ultimate greenhouse liquid. There are minor forcings to this effect like plankton, wind and the angle of the sun's rays. Most likely it is not radiation back into space, it is evaporation (phase change) and convection. The heat is re-radiated into space from the upper levels of the atmosphere when the water vapor changes phase back to water. That's why you can see the tracks of hurricanes in the ocean surface temperatures for a time after a hurricane passes. Mess with evaporation and you really do have a problem.
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  20. In your rebuttal it might be worth adding that, as Tyndall and others have proved in the laboratory that CO2 absorbs infrared radiation, the onus is well and truly on the skeptics to prove that CO2 behaves differently in the atmosphere. This is how I worded it on 22 Sep 2010 in my article Climate Change: The 40 Year Delay Between Cause and Effect: "There should be no dissent that CO2 absorbs infrared radiation, because that too has been demonstrated in the laboratory. In fact, it was first measured 150 years ago by John Tyndall using a spectrophotometer. In line with the scientific method, his results have been confirmed and more precisely quantified by Herzberg in 1953, Burch in 1962 and 1970, and others since then. Given that the radiative properties of CO2 have been proven in the laboratory, you would expect them to be same in the atmosphere, given that they are dependent on CO2’s unchanging molecular structure. You would think that the onus would be on the climate skeptics to demonstrate that CO2 behaves differently in the atmosphere than it does in the laboratory. Of course they have not done so."
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  21. If some skeptics were right in claiming the greenhouse effect had indeed been falsified, then that would apply to the greenhouse effects of water vapour and methane as well as CO2. Sorry to point out the obvious, but any high school kid can demonstrate the greenhouse effect of water vapour simply by correlating overnight minimum temperatures with cloud cover. An example of this simple exercise is provided on my web site (www.climatechangeanswers.org/science/homedemo.htm). (My apologies to the better informed skeptics, but outright denial of the greenhouse effect has to dealt with forcefully)
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  22. Well, The Inconvenient Skeptic expressed some dismay at the entire thrust of the rebuttal, saying "I am not aware of anyone saying there is no greenhouse effect... This article seems intentionally written to insult people that disagree with the theory that the currently increasing CO2 is going to significantly alter the Earth's climate." So I am obliged to RSVP for providing evidence that, far from this being some kind of intentional - and fictitious - slight aimed at skeptics, even on this site we are obliged to address posters who don't understand the greenhouse effect, energy budgets, radiation, heat transfer or the role of GHGs - while these same posters feel they are able to take issue with the scientific complexities of AGW. Thanks also to those more patient than myself, who took the time to explain some basic facts to a poster I suspect has no interest in them (to judge by the amount of time he spends here, and how little he has absorbed while doing so).
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  23. KR at 15:06 PM on 20 October, 2010 Yes, it is proof of a transition, not of the greenhouse effect itself. Im a believer in accuracy in these things is all. Its not my call end o the day. But it seems a simple alteration, to: evidence of an enhanced greenhouse is etc... as e said. But ill say no more on the matter ;-)
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    Moderator Response: [Graham] Joe - I too think your point is valid and accurate, but it does seem to me a rather arcane point for the basic version. I always struggle with these posts, trying to walk the fine line between brevity and over-simplicity. In this case, since the distinction is clearly addressed in the intermediate version and I can't figure out how to qualify my remark without expanding into more explanations (and qualifications) I've elected to leave it as it is. I do acknowledge your comment however, and agree you are strictly correct.
  24. gpwayne #72 "no interest in" (facts) Would you be just a little concerned if the fan on your CPU died? Why isnt radiation sufficient to cool that big chip? Or if you happen to burn you finger, why not just point it skyward? No, you put it in water because the fact is, convection provides a faster channel to dump energy. Our lives are governed by facts, even if we are successful living off of hype.
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    Moderator Response: [Graham] Your straw argument does not pertain to climate change or the planet's energy budget, primarily because it is the current speed with which equilibrium is reached that determines the acceptible limits of our climate (acceptible being what we are used to, what we humans have come to depend on, what we know sustains our agriculture etc). The absence of convection does not preclude heat transfer by radiation, in the same way the absence of water vapour does not inhibit the movement of LWR through a gaseous medium such as a mixture of oxygen and nitrogen. The speed of the transfer is, in fact, the point at issue, because the greenhouse effect slows down the radiative transfer through GHGs re-radiating LWR at specific wavelengths in random directions, thus impeding the direct transfer of heat back to space.
  25. Graham... "greenhouse effect slows down the radiative transfer through GHGs re-radiating LWR" IR travels at the "speed of light", some 3 x 10E8 meter per second. Maybe you can explain where the delay is coming from? More relevant to what you mention, you can model the spinning Earth as getting hit with a heat pulse. Temperature rises and falls. Your CO2 affecting the droop, such that it doesnt get as low with less CO2. Miraculously, even though temperatures during the year can get far below zero, somehow due to this process energy is mysteriously accumulating. If so, it can only be doing so in the materials that do not emit IR, not in those that do. AGW depends on this pin ball machine model where the IR is bouncing around as if lost and unable to escape. I believe warming is happening, but I do not believe it is happening for the reasons you do. For this I must be burned at the stake for "throwing stones".
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    Moderator Response: The delay is simple to explain, so simple that I believe you already understand it but refuse to stop digging. However, for the sake of completeness, the delay is the same as in any journey - if you take a detour or backtrack, the journey takes longer. The difference between direct radiation into space and radiation that eventually reaches the same place having bounced around our atmosphere a bit first is the measure of that delay. The rest of your post is of a standard consistent with your first, and I decline to indulge your contrarianism any further.
  26. Miraculously, even though temperatures during the year can get far below zero, somehow due to this process energy is mysteriously accumulating. A miracle to the slow-witted, perhaps, but not for those who understand that temperature is expressed on a continuum, not as a binary state, that while a thing may still be said to be cold, it may yet be warmer than in times past. If so, it can only be doing so in the materials that do not emit IR, not in those that do. Would you mind naming just one element, compound or mineral found on Earth that is not capable of emitting IR? If you can't, will you promise to always listen carefully? AGW depends on this pin ball machine model where the IR is bouncing around as if lost and unable to escape. Amazing how close you can get to surrendering and admitting you understand this process, while still eluding the final moment of capture. For this I must be burned at the stake for "throwing stones". No fear, not only does nobody see you as a fitting candidate for martyrdom, all you need do is wish different physics into being and you'll be entirely impossible to ignite.
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  27. One of the ways you can see the greenhouse effect at home is simple. Take a remote temperature sensor (IR) and point it skyward on a clear day or night and on a cloudy day or night. The clear sky (absolutely no visible clouds) will register -50F or lower. The cloudy sky will register in the 30F range. The same sensor pointed at the sun will not register much different. This is why you have dew fall at night and ice on the windshield in the morning when the air temps are above freezing. At least in my area the really hot weather (hot and humid) comes in the summer when hot, humid air from the GOM blows in. The heat in this air is imported from the Gulf by horizontal convection (wind) and remains hot day and night. Much of Europe would be much colder if it wasn't for heat transfer by way of horizontal convection in water (Gulf Stream) and then wind blowing that heat to cover the land. This is the general picture of the greenhouse effect, not to be confused with the particular picture the OP is saying skeptics hold, that the greenhouse effect due to CO2 doesn't exist.
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  28. doug_bostrom #76 "Would you mind naming just one element, compound or mineral found on Earth that is not capable of emitting IR?" My reference to "materials that do not emit IR" is like speaking about people with no brains, or as you say, the "slow-witted". Since you have read my earlier posts, you know very well I was referring to the relatively lower emissivities of N2 and O2. At any rate, to answer the question, IR is can only be emitted from the surface of things, all else is incapable of this, which just happens to make up about 99.99999% of the Earth's material. Hope this helps.
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  29. #75 "The difference between direct radiation into space and radiation that eventually reaches the same place having bounced around our atmosphere a bit first is the measure of that delay." We experience delays in communication systems daily. These may last two seconds at the most. Are you trying to say that two more seconds of lingering heat after the Sun sets is causing global warming?
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  30. #75 Have you said how you believe warming is happening then?
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  31. I have a question I think is reasonably relevant to this post. (If not, maybe someone can direct me to a more relevant one.) Is there any published data or theory on how long it takes for the global climate to equilibrate after an increment in [CO2]? To put it another way: can we assume that if we stabilized the the [CO2] today at the current level, that temperatures will have stabilized by, say, next year? Next decade?
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  32. VoxRat #81: See this article. Basically, while some temperature feedbacks (e.g. ice albedo) would take centuries to fully materialize most of the warming for a given CO2 level would be evident within about 40 years.
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  33. Thanks, CBD. (There's something wrong with that link but I gather this is what it's supposed to be: http://www.skepticalscience.com/Climate-Change-The-40-Year-Delay-Between-Cause-and-Effect.html )
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  34. hapivibe #80 Yes, but for the blow by blow you would have to go to the thread that argues for the contribution of industrial waste heat. If anything changed in my mind from that discussion, it was 1) an increase in CO2 simply redistributes energy vertically, such that it might be a tad warmer in lower altitudes at the cost of a cooler stratosphere, and 2) any additional energy that is accumulating has its source in industrial waste heat (this means the total amount of exothermic energy released since the beginning of the Industrial Revolution)... which is consistent with AGW's model that assumes forcings have only favored retention of radiative energy, so this extra energy (accounting wise) has had no outlet so that any extra energy has simply been accumulating, and 3) the effect is clearly observable in retreating glaciers, etc. I will admit that it may be hard to tell the difference as to what is going on given that heat is heat is heat, however the implications for CO2 are very different. AGW folks are the real unprepared optimists, because they think this problem will go away when CO2 emissions are reduced, when in fact the level of stored energy has no reason to drop without a significant radiative forcing also dropping off.
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    Moderator Response: No more discussion of waste heat on this thread. In the Search field type "waste heat."
  35. The thought experiment on how an atmosphere without GHGs would affect (or otherwise) the Earth's temperature is interesting. Looking at an old post by Eli http://rabett.blogspot.com/2009/12/answer-to-puzzler-couple-of-days-ago.html it appears that the atmosphere sans GHGs is almost transparent to IR: "If there is no absorption at a particular frequency you are looking at emission from the surface." This implies to me that the atmosphere is far too thin to act as a blackbody and merely transmits surface emitted radiation. Ergo the surface temperature would average -15 or whatever the albedo corrected blackbody temperature would be. I'd guess that convection would smooth day/night differences to somehat less than would be the case for no atmosphere whatsoever. I look forward to those with more expertise than me critiquing this ! On a somewhat related point - the lapse rate is something I've never really understood properly. What would be the atmospheric temperature profile in this scenario?
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  36. @Very Tall Guy "Looking at an old post by Eli... it appears that the atmosphere sans GHGs is almost transparent to IR: ... This implies to me that the atmosphere is far too thin to act as a blackbody and merely transmits surface emitted radiation." If you remove GHG (See Doug's Graph on page 1) not only will you emit IR to space but you will get far more energy at the surface because GHG also block a lot of the UV coming in. Anyway, Doug's graph shows how the black body temperature could shift to the right without any CO2. But looking at the bigger picture, if you could somehow remove water vapor and still keep the oceans you still would absorb a huge amount of solar radiation and not emit it back to space. The ocean's albedo is extremely low which means whatever gets in very little gets out. This includes IR. Water is a GHL (Green House Liquid).
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  37. "all you need do is wish different physics into being and you'll be entirely impossible to ignite" doug_bostrom wins the Internet.
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  38. TOP, >The ocean's albedo is extremely low which means whatever gets in very little gets out You've got that backwards. Kirchoff's law states that low albedo implies high emissivity. If something absorbs more energy then it also has to emit more. This is a consequence of the 2nd law of thermodynamics.
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  39. RSVP, The travel time of emitted photons is not the only thing determining delay. There is also a delay between absorption and subsequent emission of said energy. The rate of this emission is bound by the Stefan-Boltzmann Law. Also consider that we aren't talking a single round trip transmission like in your communications example. The energy could be "bouncing around" many times.
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  40. And, very importantly, a planet and an atmosphere with GHG's has a very different emission spectra than one without GHG's - it has notches where ~half the IR gets re-emitted back to the surface. In order for the integrated thermal spectra leaving the atmosphere to equal the energy coming in as sunlight (where the atmosphere is essentially transparent), a planet with GHG's (notched spectra) must have a higher temperature than one without (close to blackbody spectra), when both are at equilibrium.
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  41. An image illustrating the GHG notches from Has the greenhouse effect been falsified: Integrating under the curve of the top image gives you the total energy radiated to space. Without GHG's the spectra would be a smooth curve (lacking notches), and a lower temperature would give an equal amount of energy radiated to space.
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  42. RSVP honestly your perceptions are so muddled or at least dysfunctional in the mechanical sense that it's very hard to understand what you're intending to convey. What your words rather clearly implied is that certain tangible things on Earth can emit IR while others may not. If you were referring to surface area as opposed to volume or more precisely specific heat times mass being a measure of ability to store energy, find a way of saying so that is articulate. Elsewhere on Skeptical Science you've demonstrated a clear inability to discern between orders of magnitude, or at least you're unable to admit how you do understand such a thing as 10 X 1 = 10. This is consistent with such confused remarks as "We experience delays in communication systems daily. These may last two seconds at the most. Are you trying to say that two more seconds of lingering heat after the Sun sets is causing global warming?" Our (or my) understanding of what you know is based on what you say; with your track record of misunderstanding I'm simply going to read what you say and not attempt to use x-ray vision to tease out whatever cogs are seized up and stripping on their axles in your brainbox. All this would ordinarily be fine and dandy; it's a fact that people here are usually amazingly kind and patient. Some of us (me, again) become irritated with you when you express your inner fog with assertions implying your perspective is more useful, such as the embarrassingly tangled "AGW folks are the real unprepared optimists, because they think this problem will go away when CO2 emissions are reduced, when in fact the level of stored energy has no reason to drop without a significant radiative forcing also dropping off."
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  43. doug #92 Simpifying... the answer to your question... A hot nugget will radiate, but not when buried in a hole in the ground. As for the rest, take a break. See you tomorrow.
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  44. RSVP, wth? You aren't even trying anymore. So it's not true that any object above 0K will radiate? You should win the Nobel for this one. Tell me something, though: how does the nugget know when it's surrounded by ground? Is there a God particle involved? Does the nugget somehow magically 'sense' that it's surrounded by ground and stop radiating?
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  45. RSVP, Any object with a temperature above 0K never stops radiating - ever. Finding an object that does not radiate, or a process to make any object not radiate, would unsettle our most basic understandings of the physical universe. DSL, RSVP is trying. He's trying to force the accumulated scientific knowledge to conform to his preconceived notions.
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  46. RSVP at 20:30 PM on 20 October, 2010 says "IR travels at the "speed of light", some 3 x 10E8 meter per second. Maybe you can explain where the delay is coming from?" Ok... all matter radiates, a rock dosnt just radiate at its surface, it is radiating according to its temperature all the way through its center, but rocks are extremely opaque to both LW and SW. So what this means, is that the energy transfer through radiation, through its center, is indistinguishable from conduction, its a differential in T that allows a flow of heat, if something is extremely opaque to LW radiation, the difference in T between molecules will be very similiar, limiting the amount of energy able to be transmitted, which will be a result of its boundary conditions, at what rate it is absorbing, or emitting energy. With a temperature gradient necessary to allow a flow of energy through radiation (or conduction, or convection, but rocks dont convect very well at normal terrestrial T's). The reason is simple, if its neighboring molecule is at the same T, it will be emitting the same as it is absorbing. Essentially meaning no change in energy. Or local thermal equilibrium LTE. So by increasing the opacity of a gas, you are essentially restricting the distance energy can travel via radiation. Making it behave more like a solid, in regards to the passing of energy through LW radiation. The temperature gradient, will restrict the flow of energy out of the system, because it is only the net difference between layers that is being transmitted. And the more opaque a gas is, the shorter the distance between the emitting and absorbing molecule will be, the smaller the difference in T will be between molecules, the smaller the amount of net energy flow will be. And thats why.
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  47. doug_bostrom #92 As I was asked to take my comments about waste heat to the the Waste Heat thread, I have taken the opportunity and even dedicated my post to you based on your remarks in #92.
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  48. Speaking of the strength of the greenhouse effect and what would happen if you took out all the C02, the good folks at NASA have just published a paper in Science looking at precisely this question. The Science paper is here but for those who can't access it there are good discussions on the NASA GISS website (including most of the figures from the Science paper) here and here. The answer seems to be that while C02 (and other GHGs like methane) make up around 25% of the greenhouse effect, without them water vapor crashes out of the atmosphere, leaving a planet with an average temperature of -21dC. It might not be a completely snowball earth though, the equator may get enough heat to keep the oceans at a balmy 1dC. Interesting stuff, but the take home message is spelled out in the title of the paper: "Atmospheric CO2: Principal Control Knob Governing Earth’s Temperature"
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