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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 100251 to 100300:

  1. 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?
  2. 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.
  3. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    This is drifting way off topic again ...
  4. 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.
  5. 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!
  6. 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 ?)
  7. 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.
  8. 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.
  9. 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?
  10. 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.
  11. 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)
  12. 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.
  13. 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.
  14. 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.
  15. 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.
  16. 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.
  17. 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.
  18. 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.
  19. 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.
  20. 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.
  21. 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.
  22. 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.
  23. 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.
  24. 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.
  25. 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.
  26. 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.
  27. Lindzen and Choi find low climate sensitivity
    KR, re 389 I refer to to post 387 which disputes your point.
  28. 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.
  29. 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?
  30. 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.
  31. 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.
  32. 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?
  33. 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.
  34. 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.
  35. 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
  36. 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.
  37. 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.
  38. 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.
  39. Lindzen and Choi find low climate sensitivity
    co2isnotevil, a question for you. 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? If so, show any scientific source that confirms that SB includes nonradiative transfer. If not, please correct RW1's misconception and then explain why latent heat and thermal transfer to the atmosphere can be ignored (along with solar heating of the atmosphere)
  40. Lindzen and Choi find low climate sensitivity
    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. The temperature (at dynamic equilibrium) of the surface of the Earth is determined by input energy from the sun to the surface and atmosphere and the effective emissivity of the Earth, which notably changes due to GHG concentration. Without GHG's it would be at least 33C colder, for example. Again, as stated here: don't talk about 3C warming from a 3.7 W/m^2 CO2 forcing unless you include the feedback that raises 1.2C forcing to 3C temperature change. That's the climate sensitivity, which (primarily through water vapor effects) is expected to multiply the forcing by ~2.5. You seem to keep mixing the total forcing+feedback to try to argue against the forcing.
  41. Lindzen and Choi find low climate sensitivity
    KR, The difference between a BB and a grey body is well known and included in any radiative analysis. Inferring that I don't understand this tells me that you aren't paying attention. The fact that you're missing is that the surface is almost an ideal BB radiator, especially in the LW IR. The Earth itself, as seen from space, is a grey body because the atmosphere is between the surface and space. Perhaps it would also help if you understood that the theoretical maximum blocking of surface power by the atmosphere is 50%. You can test this yourself by comparing the power radiated by the coldest cloud tops and the power radiated by the surface beneath them. This will never be less than 1/2. Venus is somewhat different because the thermal mass of the planet is primarily energized CO2 above the surface, while on Earth, it's ground state water below the surface. You also don't seem to understand the Stefan-Boltzmann Law. If the surface temperature increases by from 287K to 300K (a 3C rise), it's emitted power must increase by 16 W/m^2. Conservation of energy tells us that this power flux must be coming from somewhere. There is about 3.8 W/m^2 of incremental absorption by doubling CO2 (run modtran yourself if you don't believe me). Only half of this affects the surface, so I ask you, in order to satisfy COE, where is the extra 14.2 W/m^2 coming from? If you think it's the feedback, then I suggest you go back and study Bode and basic thermodynamics.
  42. Lindzen and Choi find low climate sensitivity
    Mea culpa - I believe I have misinterpreted a couple of things in the last post. A 3C warming (total, from whatever source) of the surface will result in 16.8 W/m^2 increase (14C to 17C) in surface IR. At dynamic equilibrium this means an additional 16.8 W/m^2 of backradiation, +/- depending on what's changed in terms of thermal and evaporation pathways. The emissive levels in the troposphere would likely be higher, too, lots of other changes. We would still expect a power flow of ~240 W/m^2 from the sun and ~240 W/m^2 out to space as IR - the surface temperature will be driven by the input energy and total emissivity required to radiate that energy. A single 'gain' factor doesn't encompass the details of that. However - The 3.7 W/m^2 forcing from doubling CO2 will result in a direct forcing of only 1.2C. The value of 3C surface warming includes current estimates for climate sensitivity (look, actual relevance to the thread!). Hence arguing that 3.7 W/m^2 of direct forcing can't cause 16 W/m^2 of direct + feedback is mixing apples and oranges, and is a bad argument. We know what the direct forcing for a CO2 doubling will be. The climate sensitivity is rather more debatable, but appears to be ~3C for that doubling. And that means ~3C for 1.2C of solar forcing, if the insolation changes that much. Argue the forcing, or argue the sensitivity. Claiming the sensitivity issue(s) invalidate the forcing is really pointless.
  43. Lindzen and Choi find low climate sensitivity
    co2isnotevil, in your first paragraph in 374, the Pc calculation doesn't matter, nor does Pe. As I pointed out in 208, that tangent is dropped and "gain" is determined solely from Ps. That's one of my lessons learned, don't follow tangents and don't start them. In this case I was following a tangent in the paper. As for "gain" itself, that has more than adequately been addressed above such as in 210.
  44. Comparing all the temperature records
    47: "no starting or ending point can ever be wrong. Also, any period length is allowed" Sorry, but you are incorrect. See the thread on statistical significance and the thread on misuse of significance tests for starters. Significance of measurement is a fundamental point in every science; misuse in any form is a serious and very common flaw. But you obviously understand that; why else would you bring up your 'longest cold spell'?
  45. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    Is there any point in reducing my "carbon footprint" by 50% (even if I could) if the Earths population is set to double in the next 50 or 100 years ? Surely carbon use is an effect and population growth a cause, and not one which politicians will relish tackling ?
  46. Lindzen and Choi find low climate sensitivity
    KR, "The Earth is not a black-body radiator, but a 'gray-body'" But the surface of the earth is very close to a perfect black body radiator. This is why S-B (where emissivity "e" = 1) is used to calculate equivalent surface power to temperature and vice versa. "is that it takes 16 W/m^2 of incremental surface power for a 3C rise in surface temperature" is absolutely incorrect. 3.Y W/m^2 at TOA accounts for a 1.2C CO2 forcing, and feedbacks are expected to raise that to 3C. A raw forcing of 3C from CO2 would require 9.25 W/m^2, and from that we would expect 7.5C of rise with feedback. Your 'amplification factor' is nonsense." From S-B, at a surface power of 396, it takes 16 W/m^2 of additional power to increase the surface temperature 3 C. (396 + 16 = 412 W/m^2; 412 W/m^2 = 292K; 292K-288K = 3C).
  47. Comparing all the temperature records
    Norman (#15, #19, #22) had the audacity to point out a recent period of time, where he saw, if not a cooling trend, at least not a clear warming trend. For this 'felony' he was ridiculed by other writers (e.g. ##23-28). - "Norman, I was driving back down south for Christmas and halfway along I drove over a mountain pass. From this I have concluded that driving south is all downhill." He was accused of "cherry-picking of the highest order", or "blatant cherrypicking" (whichever is worst). He committed a climate faux pas. He is probably not ever coming back to this forum (re: #27). But Norman also got pieces of friendly advice in several comments, like, - please, take a look at other 12-year periods as well, or - please, use a longer period than 12 years. Specifically he was encouraged to not use 1998 as the starting point (because it was a warm year), but instead use another year, like 1997 or 1999 (because those were colder years). Voila, no trend! My experiences, from reading countless posts and comments on this website, tell me that if the purpose is to show something that is connected to warming (whether it be temperature curves, polar ice melting, or coral depletion) - no starting or ending point can ever be wrong. Also, any period length is allowed: 10 years, 12, 17, 30, or 87 years - all are OK. It doesn't matter as long as the cause is to show warming. However, if you want to present a trend that is connected to cooling, or even to warming at a slower rate, there are many important rules that you have to follow. Basically, don't go there! By the way, here in Stockholm, Sweden, we have now had the longest continuous cold spell since the winter of 1788-1789 (yes, we have a long unbroken series of temperature measurements, starting in 1756). But hey, that's only where I live, and that's not very global is it?
  48. Lindzen and Choi find low climate sensitivity
    co2isnotevil - Your post here has far more incorrect statements than correct ones (if any). The Earth is not a black-body radiator, but a 'gray-body', as seen in the TOA spectra (Figure 1 here). The 'gain' is a variant result, not an input, and doesn't actually relate to the visible light input power and thermal IR output power physics. "is that it takes 16 W/m^2 of incremental surface power for a 3C rise in surface temperature" is absolutely incorrect. 3.Y W/m^2 at TOA accounts for a 1.2C CO2 forcing, and feedbacks are expected to raise that to 3C. A raw forcing of 3C from CO2 would require 9.25 W/m^2, and from that we would expect 7.5C of rise with feedback. Your 'amplification factor' is nonsense. http://www.palisad.com/co2 consists of exceedingly bad numbers (as I noted here), misinformation, and a collection of denier themes that can be found searching the top 20 skeptic arguments here. That's not a good source, but rather a quick trip into irrelevancy. I could go on, but I quite frankly don't see any point in it.
  49. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    See also the Extreme weather thread, especially the Hansen quote here.
  50. Lindzen and Choi find low climate sensitivity
    Bibliovermis, re #233 and many that followed Forcing has no implicit time over which it occurs, only a time by which the system responds, known as the time constant. http://en.wikipedia.org/wiki/Time_constant The climate is readily modeled as a first order LTI as, Pi = Po + dE/dt, where Pi is the power arriving from the Sun, Po is the power leaving the planet and E is the total energy stored in the Earth's thermal mass. When dE/dt is positive, the planet warms and when negative, it cools. Po is dependent on reflectivity and the temperature of the thermal mass and other factors dependent on E, collectively lumped into tau, thus fitting the general form of an LTI described by the above wikipedia entry as, dE/dt + 1/tau E = (1-r)Pi, where r is the reflectivity and (1-r)Pi is the forcing function f(t). This is where the definition of forcing actually comes from. In fact, GHG absorption influences the time constant and is not even properly considered forcing. Only power from the Sun can actually force the climate system, what the IPCC considers forcings simply modify the systems response. This is yet another manifestation of the confusion between gain and feedback where forcing and the response to forcing are similarly confused. The response of such a system to an immediate change is called it's impulse response and takes the form of the decaying exponential exp(-t/tau). If the forcing function is a sinusoid of the form exp(-jwt), the steady state solution (after at least 4-5 periods) is a delayed sinusoid of the form exp(-jwt)/(jw+1/tau). There's a second differential equation which relates the capacity and transfer characters of a thermal mass to dT/dt and F (also shown in the above wikipedia entry), where the flux F, is equal to dE/dt. The linear relationship between dE/dt and dT/dt is often misapplied to infer a linear relationship between 'forcing' and temperature, justifying a linear sensitivity, except that dE/dt is not the forcing, Pi is the forcing function and dE/dt is the response to that forcing. Finally, solar power is far from constant. It has latitude specific daily and seasonal variability all of which are easily represented as functions of the form exp(-jwt) and from which the time constants can be inferred by measuring the response to such stimulus. If indeed this was not relevant, there would be no differences in the climate between night and day, summer and winter or even latitude. There are also long and short term solar cycles and Milankovitch forcings affecting solar variability. It's not the average magnitude of solar radiation, but how that intersects with hemispheric and seasonal specific reflectivity.

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