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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 100051 to 100100:

  1. Lindzen and Choi find low climate sensitivity
    co2isnotevil at 12:37 PM on 28 December, 2010
    "I also suggest you review a little about control theory, time constants and how they operate. If the planet was as sluggish as you claim, then how do you explain the global temperature changing by over 3C during a 12 month period? A time constant of 7.5 years says that it takes 7.5 years for 37% of the equilibrium change to occur. Do you not believe that the Sun forces the climate? How can you even explain seasonal change?"
    (i) Note that the time constant is the time for ~63% (1-1/e) of the equilibrium response to be achieved (not 37%). (ii) The global temperature changes seasonally due to the large excess of N. hemisphere land compared to the S. hemisphere and the lower heat capacity of land compared to ocean. In other words one of the more rapid elements of the climate system (land warming) dominates when the N hemisphere is tilted towards the sun even although this occurs during the short period that the Earth moves to and from aphelion. Temperature changes of the vast S. hemisphere oceans occur much more slowly than N hemisphere land. (ii) The seasonal changes result from varying insolation patterns (with a lesser effect from the change in surface solar irradiance due to orbital eccentricity). (iv) this is all obvious. Clearly if the Earth were to come to a grinding stop in its orbit at aphelion and sit there rotating as normal, the N. hemisphere would warm further. However the orbital properties of the Earth aren't very relevant to persistent changes in forcings that are fundamental to determination of climate sensitivities. That's because the orbitally-paced sinusoidal insolation occurs more rapidly than the various elements of the climate system can equilibrate with the changing forcings, and thus average out on time scales relevant to establishing the Earth's equilibrium response to forcing.
    "...intrinsic 0.5C or so from doubling CO2 will melt enough ice to affect a 3C global temperature rise..."
    That's just argumentation co2isnotevil. To establish the physical response requires an effort at rigorous analysis. The intrinsic response to a forcing equivalent to a doubling of atmospheric [CO2] is of the order of 1 oC and then one needs to factor in the water vapour feedback (lots of evidence that this is positive and rather significant) and land and sea ice melt. There is a vast science on this (e.g. check to loink in post 413). One of the essential problems that you and RW1 have failed to address is the empirical evidence that the Earth's climate sensitivity is very unlikely to be below 2 oC (as explained, for example, here, and here, and here and here)
  2. The Scientific Guide to Global Warming Skepticism
    39, Eric: If you're interested in finding out the truth, you have to argue TO THE POINT, not just to avoid the point. Looking for a causal basis for global warming in cosmic rays is a lost cause.
  3. Lindzen and Choi find low climate sensitivity
    I agree with Chris that deleting those comments is counter productive to the thread. The response time of the climate system is intimately related to the sensitivity. High sensitivities are claimed only when then can also claim that the affect is deferred decades into the future because we can't discern from the data what current CO2 concentrations are supposed to have done. For example, there is no monotonic trend corresponding to the CO2 trend in the temperature data.
  4. Lindzen and Choi find low climate sensitivity
    Chris, No. L&C do not treat the tropics as a closed system. They treat it as part of a closed system whose specific behavior is linked to the behavior of the whole. Besides, the specific complaint was that the coverage was only between -20 and 20 degrees latitude and not that they were treating that region as a closed system. Have you even looked at full coverage surface temperature reconstructions? Consider the ISCCP reconstruction which is exactly as you claim. Here is the monthly global temperature plot. You might notice the spike around 10/01 which was caused when the transition from NOAA-14 to NOAA-16 didn't fit within the ability of Rossow's code to properly adapt and the baseline shifted. I pointed this out more than 3 years ago and while Rossow acknowledged the error privately, it has yet to appear in the formal errata and this is a bigger error than anything else reported. Here is the same reconstruction with 5 year averaging applied. In both plots, the red is the monthly temperature and the black dotted line is the running 12 month average of the red line. Notice how when 5 year averaging is applied a 1 month data anomaly suddenly appears as a multi year temperature trend? This shows the same data where the baseline has been corrected and this shows corrected data with 5 year averaging. Hmm. It seems that Hansen's data is showing a cooling trend? How odd ,,, I also suggest you review a little about control theory, time constants and how they operate. If the planet was as sluggish as you claim, then how do you explain the global temperature changing by over 3C during a 12 month period? A time constant of 7.5 years says that it takes 7.5 years for 37% of the equilibrium change to occur. Do you not believe that the Sun forces the climate? How can you even explain seasonal change? The ebb and flow of glacial ice works on a somewhat larger scale, but if you're seriously trying to claim that the intrinsic 0.5C or so from doubling CO2 will melt enough ice to affect a 3C global temperature rise, you better go back and run your numbers again. Even your inflated 1.1C intrinsic effect is not enough. We are pretty close to minimum ice, as we are during every interglacial epoch, and as such, there is not enough ice to melt and cause your hypothetical 3C rise. Ice related feedback is a clamped effect and you can't equate the effects of ice melting as we are leaving maximum ice with those with ice melting when we are already at minimum ice.
  5. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    I also expect another stepwise jump over the next few years. The following graph is very sloppy. I only use it as a kind of sketch to easier convey why I think a stepwise jump is imminent. The red line is HadCRUT3. The green line is just an arbitrary "background warming" curve (just to be able to say "hey even a curve fits this data"). The purple line is ENSO (MEI index). The orange line is sunspot number. The gray line is volcanic forcing taken from the modelE data file. The blue line is all the previous lines added together and doing that matches up with HadCRUT quite well. If I leave out the solar cycle I get a much worse fit. I have the scalings all written down and I update it every few months - the graph below goes up to November (except the HadCRUT3 red line which only goes up to October) From this you can see that what skeptics call "global warming stopping", ie the flat period since about 2002 is actually compatible with a background warming of about 0.15C during this period that's pretty well all canceled out by the negative ENSO and solar trend. To stall the warming indefinitely solar output and ENSO would have to keep declining. But they are both pretty well bottomed out now, in fact more likely than not over the next few years both ENSO and the solar cycle will contribute positively, therefore far from negating the longterm warming trend they are going to supplement it. Which is why I think a step change is already underway in global temperature. Although thanks to ENSO noise it will take perhaps a few years to be able to look back on the record and identify a step change has occurred.
  6. Lindzen and Choi find low climate sensitivity
    It's unfortunate that a moderator has deleted the last two comments (co2isnotevil's and mine) since these get right to the crux of the issue. It's directly relevant to the Lindzen and Choi analysis and to all attempts to establish equilibrium Earth response climate sensitivity by analysis of transient responses to forcings. I'll post the relevant bit of my deleted post. If the moderator considers this non-relevant (discussion of climate response times to forcing) then something's badly amiss!
    co2isnotevil: "The Earth responds far more quickly to changes in forcing than you think."
    Yes, it responds immediately to changes in forcing. However in establishing the climate sensitivity we are interested in the response when the system has come to equilibrium with the forcing. This is a fundamental error that your website and RW1 are simply not addressing.
    co2isnotevil: "The climate system's time constant is on the order of 2 months"
    That's horribly incorrect. Even the most generous models of Earth climate response to forcing arrive at a time constant [time for the response to achieve (1-1/e)-fold magnitude of its equilibrium response] of around 7.5 years (see discussion here here, for example). Of course there are several time constants of relevance (the atmosphere responds faster than the land surface which responds faster than the ocean surface...the response of the deep oceans is very slow indeed). It's very easy to see that this must be the case, and must be considered for determination of the climate sensitivity. The sea and mountain ice response to warming is a significant part of the climate sensitivity. As sea and land melts in a warming world the Earth albedo reduces. It's not possible to maintain the ludicrous notion that this response comes to equilibrium with a time constant of 2 months! Try 20 or 30 years (and maybe 100-1000 years for polar ice....
  7. Lindzen and Choi find low climate sensitivity
    chris, Would you consider a pot of water at thermal equilibrium on the stove with the burner underneath at a fixed setting as being analogous to the oceans of the Earth (the water in the pot) and the current amount of average radiative forcing acting on them (the burner underneath)?
  8. Lindzen and Choi find low climate sensitivity
    co2isnotevil at 11:12 AM on 28 December, 2010 There is an inherent illogic in your attempt to equate: (i) the very specific flaw (of Lindzen and Choi) of attempting to treat the tropics as a closed system for attempting to assess readiative flux responses to changes in surface temperature (when the flows of energy to higher latitudes dominate outgoing (space-directed) energy flows by factors of 10-fold)... and: (ii) the fact that Earth temperature measures are sampled at discrete points on the surface. A physicist should really be able to spot the logical flaw! In selecting to analyze data covering only the tropics (20o N to 20o S) Lindzen and Choi omit not only the massive bulk of the Earth's surface, but the regions of the Earth to which massive flows of solar energy insolating the tropics flow to higher latitudes in the shape of air and sea currents. Note that you are ignoring the particularly dismal flaw of Lindzen and Choi which is the cherry-picking of periods of temperature change (see top article above). As a scientist you really should be appalled at the level of false analysis. On the other hand the Earth temperature measurements sample virtually the entire world (with only the Arctic and Antarctic poorly sampled) and there is a huge body of evidence that: (i) the Earth surface temperature measurement is robust to at least 5 independent analyses (by teams in the US, UK, Japan and Europe), (ii) the Earth surface temperature is robust to large reduction of temperature stations (e.g. the US temperature data is hardly changed when selecting a small subselection of what a climate contarian group have asserted are the "good" set of stations by their own criteria). In other words the Earth surface temperature is over-determined and the reason for this is quite well established (it relates to the well-characterized observation of the spatial correlation of surface temperature anomalies over distances of several hundreds of kilometres). etc.
  9. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    Those green and pink lines are interesting and disturbing, haven't seen that kind of analysis of the El Nino/La Nina contrasts before. The current La NIna, in Australia at least, seems to be an especially strong one, with record rainfall events and record flooding all over the place. Is this perhaps the start of another "jump" in La Nina events, to be followed, by the look of that graph, by a particular severe El Nino and a new level for those horrific (in Australia at least) events? Sorry for my late response. I know that 31 years is a short time to be making any dramatic predictions based on a graph alone, but we had a similar jump in temperatures around 1976 and yes, we seem to be on the verge of another one. That would make this our third stepwise "jump". The way things are going, only a few more years (In the context of the past 35 years.) should tell us that this is a certain trend. There are other more disturbing trends that threaten to throw a monkey wrench into our climate but that would take us off subject again.
  10. Lindzen and Choi find low climate sensitivity
    RW1 at 10:26 AM on 28 December, 2010 ”Why is the Lindzen and Choi resulting sensitivity consistent with how each 1 W/m^2 of power from the Sun is treated at the surface, but the IPCC models that predict a 3 C sensitivity are not?” The answer is that Lindzen and Choi chose to make an erroneous analysis that gave them a result that they wittingly, or unwittingly, were aiming for. There are virtually an infinite number of ways of obtaining a false result in science RW1. Lindzen and Choi’s analysis is simply wrong as has been well established by several groups of atmospheric physicists (and see account in the introductory description of this thread): Chung ES, Yeomans D, Soden BJ (2010) An assessment of climate feedback processes using satellite observations of clear-sky OLR Geophys. Res. Lett. 37, art # L02702 abstract Murphy DM (2010) Constraining climate sensitivity with linear fits to outgoing radiation Geophys. Res. Lett. 37, art # L09704 abstract Trenberth KE, Fasullo JT, O'Dell C, et al. (2010) Relationships between tropical sea surface temperature and top-of-atmosphere radiation Geophys. Res. Lett. 37, art # L03702 abstract Chung ES, Soden BJ, Sohn BJ (2010) Revisiting the determination of climate sensitivity from relationships between surface temperature and radiative fluxes Geophys. Res. Lett. 37, art # L10703 abstract So you're really asking the wrong questions RW1. You should be pondering: (i) Why do people chose to believe analyses that are clearly and objectively flawed? (ii) How can one seriously maintain allegiance to an analysis of Earth climate sensitivity that is woefully inconsistent with straightforward empirical evidence? Remember that Lindzen’s, and the flawed analysis of the website from which you have sourced your analysis, come up with a climate sensitivity (~0.6 oC of Earth surface warming for a radiative forcing equivalent to a doubling of atmospheric [CO2]?) that is simply at odds with a vast body of empirical analysis, as explained here, and here, and here and here. (iii) How can one possibly obtain a realistic estimate of the Earth climate sensitivity (the Earth surface temperature response at equilibrium resulting from a radiative forcing equivalent to a doubling of atmospheric [CO2]), from transient temperature responses to transient variations in forcing (seasonal variations in forcing resulting from the earth’s rapid passage around the sun)? (iv) why would one raise a false argument that "the IPCC models that predict a 3 C sensitivity are not" consistent with empirical observations, when the models (they're not "IPCC models, RW1, but the models of a large body of physicists) are clearly entirely consistent with empirical observations (e.g. 20th century warming) as indicated in the links in (i) above)?
  11. Lindzen and Choi find low climate sensitivity
    The Chung et all paper is not freely available, but based on the abstract, it makes a very weak case by trying to connect the radiative dampening rate with positive feedback. The issue with the temperature measurements is homogenization (Hansen Lebedeff 1987) which incorrectly justifies the use of a very small sample set to discern trends, which tends to encourage cherry picking. My point is that none of the surface temperature reconstructions which predict large sensitivities or large warming cover more than about 1% of the planet and interpolate everything else. If you want to complain about the 30% coverage of L&C, you better start complaining about all reconstructions that do not start with 100% coverage.
  12. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    To address the issue that isn't safe to double the atmospheric CO2 content, we can: A) Do nothing but token measures while continuing Business As Usual. Why bother changing when They might not? B) Kill off 9/10ths of the world's population. C) Use the current available technology and lead the way. If we are still debating whether the atmospheric CO2 level is a concern, lets bring this discussion back on topic. Otherwise, use the search box to find a more appropriate area for discussing what we should do about it.
  13. Lindzen and Choi find low climate sensitivity
    Why is the Lindzen and Choi resulting sensitivity consistent with how each 1 W/m^2 of power from the Sun is treated at the surface, but the IPCC models that predict a 3 C sensitivity are not?
  14. Lindzen and Choi find low climate sensitivity
    co2isnotevil, This post also referenced Chung et al. 2010, which used a more global dataset and found that the results were not consistent with Lindzen. In general, the validity of the temperature records is addressed here.
  15. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    This is drifting way off topic again ...
  16. Lindzen and Choi find low climate sensitivity
    BTW, Does anyone have a link to the updated Lindzen and Choi 2010 paper? I believe the original was criticized for cherry picking data points, but when they re-did in 2010 using "all points" the result was the same.
  17. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    By the way is this site hosted in America ? It's not even 28 Dec here and I've got to go see us thrash the Aussies at cricket on TV soon !! Sorry will speak again soon.
    Response: This site is run by an Australian and hosted in Australia. Discussion of cricket is banned on this website... when Australia is losing!
  18. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    I wouldn't refuse to change, I try - I've walked to work several times recently, and wear a pullover and turn down the heating. I think changing our lifestyle drastically would help. But.... 1800AD - less than 1 billion people 1900AD - more than 1 billion people 2000AD - 6 billion 2100AD - ??? (i'm thinking it's not linear) Don't deal in cliches, do the math What nations/governments etc "have clearly stated" may not happen. Population is the issue. 300 million people in 1000AD caused no global warming (did they cause the little ice age by not keeping enough cattle to produce enough methane ?)
  19. Debunking this skeptic myth is left as an exercise to the reader
    It sounds like the facts are not good enough for this denier, and I have found that to be the case with most deniers I have talked with. I have had better luck appealing to popular figures in the government that work to mitigate climate change, such as the US Navy, Pentagon and John McCain. If the climate change issue is removed from its political "liberal" stereotype and framed as an issue that crosses political boundaries, there is a better chance of getting the point through any mental walls that some people put up. Also, I would reply back to the "I don't trust the direct measurements" with an explanation of how the measuring devices work. These instruments are somewhat abstract to the average person, and a clear explanation of how they work could go a long way to establishing trust in their results. Also, while it may be tempting to poke fun or get frustrated, we must realize that today's deniers may be tomorrow's activists. Back in college, I was in the denier camp, but now I have devoted my career towards engineering renewable solutions. We must remain civil at all times in order not to alienate anybody. Thanks so much for this website. I have been reading for a month or so, and there is a wealth of concise, distilled information here along with some pretty interesting and civil comment discussions. I've donated since this is great work that benefits the world.
  20. Lindzen and Choi find low climate sensitivity
    co2isnotevil - I believe that your objections are met in the topic itself. Lindzen and Choi's sensitivity result has a high dependence on their (arbitrary looking) start/end dates. The tropical region is not (as they seem to have treated it) a closed system, see comments in the header regarding Murphy 2010, where even small changes in tropical/polar heat exchange swamp L&C's results, that global data gives quite different results (Chung 2010), plus the multiple studies from both models and empirical data that contradict L&C's low sensitivity. That "more deterministic homogenization" won't help matters if it's incompleteness introduces errors, which it appears to do.
  21. Lindzen and Choi find low climate sensitivity
    To stay on topic, lets address the first paragraph of my first post at #297. Read that and then answer the following questions. Why don't you complain about homogenization techniques applied to a small data set with high uncertainty which predicts a high sensitivity, yet do complain when more deterministic homogenization techniques are applied to a much larger data set with less uncertainty and which predicts a low sensitivity? Are you objecting to the uncertainty in the analysis or are you objecting to the conclusion?
  22. It's freaking cold!
    #64: "... a hard core climate denier in disguise." Yes. That would explain why his name is lighting up the denier blogs with references to his 'climate astrology'. Wait a day or two, there will be an entire denial smear machine dedicated just for him. And I believe the correct form of address is Dr. __ , not Mr. ___, PhD. However, he does seem to have published papers on the relevance of early Siberian snowfall to winter forecasting, a model that has already shown a favorable track record. But then, even astrologers get one right every once in awhile? I'm not at all sure of the point of your latest graph; however, I do recognize that NH snowfall occurs primarily in the winter. As far as this being a negative feedback, it must be a very fast feedback. Surely the model is that increased evaporation from warm bodies of water leads to a wetter winter. Once that water vapor falls out (in this case, as snow), what's left to provide feedback? "it was soot." Yes, I thanked you for the soot reference, as it provided hard evidence that anthropogenic CO2 moves from source to the Arctic.
  23. Berényi Péter at 08:57 AM on 28 December 2010
    It's freaking cold!
    #64 muoncounter at 03:57 AM on 27 December, 2010 An interesting take on the extreme winter... “As global temperatures have warmed and as Arctic sea ice has melted over the past two and a half decades, more moisture has become available to fall as snow over the continents. So the snow cover across Siberia in the fall has steadily increased. The sun’s energy reflects off the bright white snow and escapes back out to space. As a result, the temperature cools.” Mr. Judah Cohen, Ph.D. of AER (Atmospheric and Environmental Research, Inc.) must be a hard core climate denier in disguise. The mechanism he is describing, to get extreme chill via warming, is a strong negative feedback loop of the finest kind. Anyway, I told you it was soot. "If cooling is hampered (e.g. by carbon dioxide), one would expect snow trend to lag insolation. But it's just the opposite." (Summer solstice is on week 25, winter solstice is week 51)
  24. Lindzen and Choi find low climate sensitivity
    Eric, The A does not include thermals and latent heat, again, thermals and latent heat only serve to move power around the Earth's thermal mass and do not participate directly in the radiative balance. To the extent that the thermal power emitted by clouds comes from evaporated water, there is a second order connection, but relative to the radiative balance, only radiation matters. In the big picture of the thermodynamic balance of the planet, clouds selectively block surface power such that the power leaving the planet is equal to the power arriving. Relative to the Trentbert picture, thermals and latent heat are returned in his mythical 'back radiation'. This is very misleading as most of the power returned to the surface is kinetic and not radiative. Only photons matter at the boundary between the Earth and space. Why is this so hard to understand?
    Moderator Response: [muoncounter] This thread is about climate sensitivity as derived in the Lindzen and Choi paper. Further discussion of the specifics of a third party website do not belong here. Please take your continuing conversation regarding how this or that particular are derived elsewhere.
  25. Lindzen and Choi find low climate sensitivity
    Mr White (co2isnotevil), in your div2 paper you state: "A further constraint of Conservation Of Energy is that the global net non radiative flux between the atmosphere and the surface must be zero in the steady state if the radiative flux is also zero. While radiative flux to and from the surface can be traded off against non radiative flux, it makes no difference to the overall radiative balance." Your prior diagram shows a radiative energy balance that excludes the latent heat and conductive (thermal driven) transfers from the surface to the atmosphere. (it is also missing the solar short wave absorption by the atmosphere). In your statement above you are declaring that the non radiative flux is zero. Can you quantify an atmosphere to surface transfer that is non radiative that balances the latent heat and conductive transfers? Can you also explain how you arrive at A=292 as a fraction of the 385 radiative flux from the surface? Thank you.
  26. Lindzen and Choi find low climate sensitivity
    KR, re 393 I suggest that you do some 3-d atmospheric simulations yourself. Start with nominal H20/O3/CH4 and simulate at 280 ppm and 560 ppm of CO2 and see the difference. The incremental absorption is about 3.7 W/m^2 and not 7.4 W/m^2. In a very limited sense the 3.7 W/m^2 represents a reduction in power leaving the top of the troposphere, but it fails to account for the delayed release of the incrementally absorbed power back into space. As I pointed out before, even if the atmosphere absorbed 100%, 50% would still leave the planet. I challenge to you to come up with a terrestrial counter example of this. I already explained why Venus is different. re 396 Do you agree that a thermal is half of a vertical circulation current whose purpose is to redistribute energy within the atmosphere? Do you agree that evaporation/weather is another circulation current operating across both vertical and horizontal directions? If these are important to the radiative balance, then why are oceanic and atmospheric circulation currents not included as well. These serve the same purpose as moving energy around the thermal mass. The fact is that the only effect non radiative energy transfer has on the energy balance is establishing the conditions for clouds to block as much as 1/2 of the surface radiation from leaving the planet. The proportion of clouds then sets the ratio of warm surface emissions and cold cloud emissions such that the radiative balance is maintained. The physical feedback system is controlling the planets energy balance. The hypothetical feedback system proposed by the IPCC controls the surface temperature. This is the source of the disconnect because the boundary conditions and output of the hypothetical feedback system are predetermined by the physical feedback system. The hypothetical system can be forced to look correct at a specific operating point, but is useless for how the system responds to change.
  27. Lindzen and Choi find low climate sensitivity
    Eric, I'm not backtracking - I'm clarifying. The 396 W/m^2 power flux at the surface already has factored into it the thermals and latent heat transfer. Without these two processes moving heat away from the surface into the atmosphere, the surface power would be about 493 W/m^2 for a temperature of about 305K. This is what the diagram is depicting.
  28. Lindzen and Choi find low climate sensitivity
    Moderator - Typo in my previous post, "appears to be list" should be "appears to be a list". Sorry for the bad grammar.
  29. Lindzen and Choi find low climate sensitivity
    Aha! I have found that "co2isnotevil" is actually George White (look for 'co2isnotevil'), creator of the http://www.palisad.com/co2 website referred to by RW1. Mr. White, please note my comments about your website in this post, also note that your slide presentation appears to be list of the top 20 skeptic arguments debunked here. My apologies, but I cannot take your comments seriously when you have such misinformation on your web site.
  30. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    The developing nations do not have to follow the same industrialization path that the developed nations did. They have clearly stated that they will not change for us but with us. Refusing to change because they might not is playing a game of chicken that there is no benefit in winning. Focusing on population growth only delays the inevitable. Population is not the issue; what the population does is.
  31. Lindzen and Choi find low climate sensitivity
    co2isnotevil you said "The simple fact is that relative to the radiative balance of the planet, only radiation matters" Do you, like RW1 believe that "A" in the div2 diagram accounts for thermals and latent heat transfer or is "A" simply the fraction of 385 being absorbed as shown? If the former, please explain why the thermals and latent transfer are not in the diagram. If the latter, please correct RW1 who said in #370 that "The 396 W/m^2 power flux at the surface already accounts for the thermals and latent heat transfer" and seems to now be backtracking. Please correct him so we can move on.
  32. Lindzen and Choi find low climate sensitivity
    co2isnotevil>The surface gain of 1.6 is a 25 year average extracted from satellite data with nearly 100% surface coverage at 3 hour samples over that period. If you are averaging the value over 25 years, then by definition you are hiding the increase over time caused by CO2 and any feedback effects. In order to quantify the strength of a changing greenhouse effect, you would have to express this gain as a delta over time, not a static average.
  33. Lindzen and Choi find low climate sensitivity
    RW1 - "I believe you were claiming that the effects of thermals and latent heat were not included in the 396 number and somehow needed to be added in to get the correct surface power or temperature" - not quite right, in some critical points. The surface temperature of the Earth radiates 396. Thermals transport 17 at that temperature, latent heat 80. That matches the 161 direct sunlight and 333 back-radiation from the atmosphere (within 1 W/m^2), energy in = energy out. If these two sums do not match, net energy will flow, the energy of the Earth's surface will change, and so will the temperature.
  34. Lindzen and Choi find low climate sensitivity
    co2isnotevil - Thermals go up, lose energy, cooler air goes down. Latent heat evaporates water, which rises, cools, and returns as precipitation. The upper atmosphere radiates energy to space (as well as to slightly lower in the atmosphere), the energy to space is lost, balancing incoming solar energy. Your post here doesn't disprove convective and thermal effects on total radiation balance, as those effects drive energy to the upper atmosphere where it then radiates to space. All of the notches in Figure 1, outgoing radiation, are IR from upper atmosphere, which receives energy from thermals and latent heat as well as IR.
  35. Lindzen and Choi find low climate sensitivity
    Eric, "Do you, like RW1, believe that the 396 W/m^2 shown in http://www.palisad.com/co2/div2/div2.html includes latent heat transfer and thermals?" I think I was referring to "A" which is 292 W/m^2 - the total power absorbed by the atmosphere. The effects of thermals and latent heat are automatically embodied in "A". In regards to the 396 W/m^2 surface power in the Trenberth diagram, I believe you were claiming that the effects of thermals and latent heat were not included in the 396 number and somehow needed to be added in to get the correct surface power or temperature.
  36. Lindzen and Choi find low climate sensitivity
    co2isnotevil, the thermal quantity in Trenberth's diagram refers to the amount of heat conducted from the surface into the atmosphere. The cold air return loop that you describe as only atmospheric is considered because it determines the amount of heat conducted from the surface (determined by the temperature difference of the surface and atmosphere). Ok, now address latest heat transfer. Does evaporation, convection and condensation transfer heat from the surface to the atmosphere? Why isn't that shown in the div2 diagram? You say that latent heat transfer is one of the "circulation currents which move energy around the Earth's thermal mass, between the oceans and clouds (evaporation)" Basically you are admitting that heat is moved from the surface to the atmosphere, why isn't it in the div2 diagram? You ask "Can you describe the physical mechanism for how a thermal will influence the radiative balance? If you really think evaporation/weather matters to the balance, then why don't you consider other oceanic and atmospheric circulation currents? " Answer to Q1 is that as conduction transfers heat from the surface to the atmosphere, the temperature of the atmosphere increases and thus the back radiation. Answer to Q2 is that atmosphere to atmosphere and ocean to ocean transfer is not part of the div2 diagram only surface to atmosphere.
  37. Lindzen and Choi find low climate sensitivity
    co2isnotevil - The forcing at the top of the atmosphere is the difference between what arrives and what leaves TOA, regardless of internal (atmospheric and surface) energy exchanges. In a single layer atmosphere (which is not the case in the actual climate) redressing that requires that the atmosphere radiate an extra ~7.4 W/m^2. Halving that means that 3.7 goes to space (correcting the imbalance at TOA), 3.7 goes to the ground. Claiming that a 3.7 TOA imbalance is halved at the surface is therefore an incorrect interpretation of the terms. Please read the thread to see the repeated corrections of this misapprehension. Given the atmospheric lapse rates, the near-total IR absorption/emission (over only a few meters) near the ground, and the fact that GHG's can only radiate to space from the colder upper troposphere, the surface IR exchanged in order to radiate 3.7 W/m^2 extra corresponds to a 1.2C surface temperature rise; about a 6.6 W/m^2 increase in surface IR and (+/-) in back-radiation.
  38. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    I'm not against reducing energy dependence, being more efficient or saving the planet's resources, as that all seems quite sensible. I am against "leading by example" if it's not a good example. Trying to deal with an effect if the underlying cause is not dealt with, and is increasing at an alarming rate, isn't going to help. I take the point that the developed world has the highest emissions, but as the rest of the world develops, their emissions will increase too. By the time the population reaches 15 or 20 billion, many more will be highly developed, using plenty of fossil fuel and with not much of the stuff left (maybe that's when we'll stop using it !!) I know there are no easy answers, as disease and pestilence (and maybe war to a lesser extent) have been the only things to reduce populations significantly in the past. However if we keep bleating about carbon footprint whilst ignore population growth we will achieve exactly nothing, or worse.
  39. Lindzen and Choi find low climate sensitivity
    KR, re 389 I refer to to post 387 which disputes your point.
  40. Lindzen and Choi find low climate sensitivity
    e, You said the gain does include feedback and that is certainly correct, but you seem to have implied that it does not. The surface gain of 1.6 is a 25 year average extracted from satellite data with nearly 100% surface coverage at 3 hour samples over that period. This certainly includes the effects of any feedback that operates on time scales of decades or less. Even the albedo effect of glacial ice is included as the gain is the average of summer and winter where the ebb and flow of the seasonal snowpack emulates the transitions between glacial and interglacial epochs. In fact, it's the increased reflectivity of the N hemisphere in winter that results in lower temperatures, even though perihelion is in Jan and temperatures should be higher. The S hemisphere operates differently because most of the surface where snow falls is water, where the snow immediately melts and can't accumulate to reflect solar power. Understanding this asymmetry is crucial to understanding how the precession of perihelion affects the climate.
  41. Lindzen and Choi find low climate sensitivity
    KR, You are incorrect because the IPCC incorrectly defines incremental absorption at the top of the troposphere as the forcing. This is because they fail to acknowledge that the atmosphere itself is a BB (actually gray) and radiates absorbed power away both up and down. Only half of the incremental absorption arrives at the surface to influence its temperature. You must get past the false authority of the IPCC before you will ever be able to understand how the climate operates. Are you trying to say that a heated gas will not radiate BB radiation? Are you trying to say that when the atmosphere absorbs power, it never leaves? Are you trying to say that all of the BB radiation of the atmosphere is directed to the surface and none into space? Which of these falsities reflects your logic?
  42. Lindzen and Choi find low climate sensitivity
    co2isnotevil - "Can you describe the physical mechanism for how a thermal will influence the radiative balance?" Yes. See the posting here.
  43. Lindzen and Choi find low climate sensitivity
    co2isnotevil> The surface gain multiplies this by 1.6 for a total of 3 W/m^2 which presents a post feedback rise of 0.6C You're not listening to what KR is telling you. Your gain value does include any climate feedbacks, it is just a quantification of the strength of the greenhouse effect for a particular time period. The feedbacks are themselves an increase in the greenhouse effect on top of the original CO2 increase, which acts to increase the gain in addition to the direct increase from CO2.
  44. Lindzen and Choi find low climate sensitivity
    Eric, The 396 Wm^2 actually comes from Trentbert's picture and corresponds to the surface radiation at an average temperature of 289K. The satellite measured average temperature is only about 287K corresponding to about 385 W/m^2 shown in div2.html. In neither case does it include thermals and latent heat. As I pointed out earlier, evaporation and weather as well as thermals comprise circulation currents which move energy around the Earth's thermal mass, between the oceans and clouds (evaporation) and within the atmosphere (thermals). Consider that hot air rising from a thermal is replaced with cold air beneath creating a vertical circulation current. What goes up must come down and what Trentbert does is lump in the energy returned to the surface as weather and originating from the latent heat of evaporation as 'back radiation' as well as the return flux from thermals. This is highly misleading and why so many are so confused. The simple fact is that relative to the radiative balance of the planet, only radiation matters. Is there any question that at the boundary of the Earth and space only EM energy arrives and leaves? Can you describe the physical mechanism for how a thermal will influence the radiative balance? If you really think evaporation/weather matters to the balance, then why don't you consider other oceanic and atmospheric circulation currents?
  45. Lindzen and Choi find low climate sensitivity
    co2isnotevil - A 3.7 W/m^2 imbalance caused by doubling CO2 (not halved, mind you, that's nonsense) will require a 1.2C rise in temperature in order for the Earth/atmosphere to radiate the extra 3.7 W/m^2 to space. That's a 6.6 W/m*2 increase in surface IR, a 6.6 W/m^2 (+/- depending again on evaporation and thermal effects) increase in surface air IR and temperature. A 3C rise will occur only due to climate sensitivity, primarily additional water vapor. Arguing against the 3.7 W/m^2 CO2 doubling forcing based on climate sensitivity, while avoiding mentioning climate sensitivity as you have, is a ridiculous argument. RW1 - Exactly right. The effective emissivity drives the temperature in the absence of solar variations. Solar variations are discussed on It's the sun - those do not correlate with recent temperature changes.
  46. Lindzen and Choi find low climate sensitivity
    KR, "RW1 - The surface of the Earth is close to being a decent black-body, with an emissivity of 0.96 to 0.99. However, the effective emissivity with cloud cover and GHG's is 0.612." Those numbers are for the whole atmosphere - not the surface. At a temperature of 289K where "e" = 0.612, the calculated power is 242 W/m^2, which is pretty close to 255K temperature as seen from space.
  47. The Hitchhiker’s Guide to the AGU Fall Meeting
    AGU's position statement on climate change can be found here: http://www.agu.org/sci_pol/positions/climate_change2008.shtml
  48. Lindzen and Choi find low climate sensitivity
    KR, The 3.8 W/m^ of incremental absorption will have only a direct effect on the surface of 1.9 W/m^2, corresponding to only about 0.4C. The surface gain multiplies this by 1.6 for a total of 3 W/m^2 which presents a post feedback rise of 0.6C, which is consistent with values presented by Lindzen, Spencer and others who have arrived at similar values by orthogonal means. Actually, doubling CO2 increases the 1.6 surface gain by about 1%, but for all intents and purposes this can be considered negligible. This is the fundamental problem. What you think of as feedback is really gain. This is a result of Hansen et all (1984) assuming unit open loop gain and which has since permeated all of pedantic climate science. The consequence is that positive feedback is required to achieve the measured surface gain and because few climate scientists, if any, actually understand control theory, the idea of positive feedback makes it scary.
  49. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    #97: "Is there any point in reducing my "carbon footprint"... " Some would call it 'leading by example' and argue its the right thing to do. Some would say you'd be contributing to wider causes (energy independence included). But if not, I suppose we could all say the same thing and justify going on with business as usual. The climate forecasts for that scenario are very unpretty. You should be aware that the developed world has the highest emissions per capita. Most of the population growth is in places where the per capita rate is much smaller. Here is a prior thread for this discussion.
  50. Lindzen and Choi find low climate sensitivity
    co2isnotevil: "There is about 3.8 W/m^2 of incremental absorption by doubling CO2 ... Only half of this affects the surface" Absolutely, completely... incorrect. This has been repeatedly pointed out since comment #7.

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