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Climate Hustle

Working out climate sensitivity from satellite measurements

What the science says...

Lindzen's analysis has several flaws, such as only looking at data in the tropics. A number of independent studies using near-global satellite data find positive feedback and high climate sensitivity.

Climate Myth...

Lindzen and Choi find low climate sensitivity
Climate feedbacks are estimated from fluctuations in the outgoing radiation budget from the latest version of Earth Radiation Budget Experiment (ERBE) nonscanner data. It appears, for the entire tropics, the observed outgoing radiation fluxes increase with the increase in sea surface temperatures (SSTs). The observed behavior of radiation fluxes implies negative feedback processes associated with relatively low climate sensitivity. This is the opposite of the behavior of 11 atmospheric models forced by the same SSTs. (Lindzen 2009)

Climate sensitivity is a measure of how much our climate responds to an energy imbalance. The most common definition is the change in global temperature if the amount of atmospheric CO2 was doubled. If there were no feedbacks, climate sensitivity would be around 1°C. But we know there are a number of feedbacks, both positive and negative. So how do we determine the net feedback? An empirical solution is to observe how our climate responds to temperature change. We have satellite measurements of the radiation budget and surface measurements of temperature. Putting the two together should give us an indication of net feedback.

One paper that attempts to do this is On the determination of climate feedbacks from ERBE data (Lindzen et al 2009). It looks at sea surface temperature in the tropics (20° South to 20° North) from 1986 to 2000. Specifically, it looked at periods where the change in temperature was greater than 0.2°C, marked by red and blue colors (Figure 1).


Figure 1: Monthly sea surface temperature for 20° South to 20° North. Periods of temperature change greater than 0.2°C marked by red and blue (Lindzen et al 2009).

Lindzen et al also analysed satellite measurements of outgoing radiation over these periods. As short-term tropical sea surface temperatures are largely driven by the El Nino Southern Oscillation, the change in outward radiation offers an insight into how climate responds to changing temperature. Their analysis found that when it gets warmer, there was more outgoing radiation escaping to space. They concluded that net feedback is negative and our planet has a low climate sensitivity of about 0.5°C.

Debunked by Trenberth

However, a response to this paper, Relationships between tropical sea surface temperature and top-of-atmosphere radiation (Trenberth et al 2010) revealed a number of flaws in Lindzen's analysis. It turns out the low climate sensitivity result is heavily dependent on the choice of start and end points in the periods they analyse. Small changes in their choice of dates entirely change the result. Essentially, one could tweak the start and end points to obtain any feedback one wishes.


Figure 2: Warming (red) and cooling (blue) intervals of tropical SST (20°N – 20°S) used by Lindzen et al 2009 (solid circles) and an alternative selection proposed derived from an objective approach (open circles) (Trenberth et al 2010).

Debunked by Murphy

Another major flaw in Lindzen's analysis is that they attempt to calculate global climate sensitivity from tropical data. The tropics are not a closed system - a great deal of energy is exchanged between the tropics and subtropics. To properly calculate global climate sensitivity, global observations are required.

This is confirmed by another paper published in early May (Murphy 2010). This paper finds that small changes in the heat transport between the tropics and subtropics can swamp the tropical signal. They conclude that climate sensitivity must be calculated from global data.

Debunked by Chung

In addition, another paper reproduced the analysis from Lindzen et al 2009 and compared it to results using near-global data (Chung et al 2010). The near-global data find net positive feedback and the authors conclude that the tropical ocean is not an adequate region for determining global climate sensitivity.

Debunked by Dessler

 Dessler (2011) found a number of errors in Lindzen and Choi (2009) (slightly revised as Lindzen & Choi [2011]).  First, Lindzen and Choi's mathematical formula  to calculate the Earth's energy budget may violate the laws of thermodynamics - allowing for the impossible situation where ocean warming is able to cause ocean warming.  Secondly, Dessler finds that the heating of the climate system through ocean heat transport is approximately 20 times larger than the change in top of the atmosphere (TOA) energy flux due to cloud cover changes.  Lindzen and Choi assumed the ratio was close to 2 - an order of magnitude too small.

Thirdly, Lindzen and Choi plot a time regression of change in TOA energy flux due to cloud cover changes vs. sea surface temperature changes.  They find larger negative slopes in their regression when cloud changes happen before surface temperature changes, vs. positive slopes when temperature changes happen first, and thus conclude that clouds must be causing global warming.

However, Dessler also plots climate model results and finds that they also simulate negative time regression slopes when cloud changes lead temperature changes.  Crucially, sea surface temperatures are specified by the models.  This means that in these models, clouds respond to sea surface temperature changes, but not vice-versa.  This suggests that the lagged result first found by Lindzen and Choi is actually a result of variations in atmospheric circulation driven by changes in sea surface temperature, and contrary to Lindzen's claims, is not evidence that clouds are causing climate change, because in the models which successfully replicate the cloud-temperature lag, temperatures cannot be driven by cloud changes.

2011 Repeat

Lindzen and Choi tried to address some of the criticisms of their 2009 paper in a new version which they submitted in 2011 (LC11), after Lindzen himself went as far as to admit that their 2009 paper contained "some stupid mistakes...It was just embarrassing."  However, LC11 did not address most of the main comments and contradictory results from their 2009 paper.

Lindzen and Choi first submitted LC11 to the Proceedings of the National Academy of Sciences (PNAS) after adding some data from the Clouds and the Earth’s Radiant Energy System (CERES).

PNAS editors sent LC11 out to four reviewers, who provided comments available here.  Two of the reviewers were selected by Lindzen, and two others by the PNAS Board.  All four reviewers were unanimous that while the subject matter of the paper was of sufficient general interest to warrant publication in PNAS, the paper was not of suitable quality, and its conclusions were not justified.  Only one of the four reviewers felt that the procedures in the paper were adequately described. 

As PNAS Reviewer 1 commented,

"The paper is based on...basic untested and fundamentally flawed assumptions about global climate sensitivity"

These remaining flaws in LC11 included:

  • Assuming that that correlations observed in the tropics reflect global climate feedbacks.
  • Focusing on short-term local tropical changes which might not be representative of equilibrium climate sensitivity, because for example the albedo feedback from melting ice at the poles is obviously not reflected in the tropics.
  • Inadequately explaining methodology in the paper in sufficient detail to reproduce their analysis and results.
  • Failing to explain the many contradictory results using the same or similar data (Trenberth, Chung, Murphy, and Dessler).
  • Treating clouds as an internal initiator of climate change, as opposed to treating cloud changes solely as a climate feedback (as most climate scientists do) without any real justification for doing so. 

As a result of these fundamental problems, PNAS rejected the paper, which Lindzen and Choi subsequently got published in a rather obscure Korean journal, the Asia-Pacific Journal of Atmospheric Science. 

Wholly Debunked

A full understanding of climate requires we take into account the full body of evidence. In the case of climate sensitivity and satellite data, it requires a global dataset, not just the tropics. Stepping back to take a broader view, a single paper must also be seen in the context of the full body of peer-reviewed research. A multitude of papers looking at different periods in Earth's history independently and empirically converge on a consistent answer - climate sensitivity is around 3°C implying net positive feedback.

Last updated on 6 July 2012 by dana1981. View Archives

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Further viewing

Andrew Dessler explains in relatively simple and short terms the results from his 2011 paper:

Comments

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Comments 351 to 400 out of 483:

  1. RW1,

    Hold on, are you thinking that solar radiation has to stay radiation as it travels through the system? If so, you are very much mistaken. Energy can and does change forms as it travels within the system.

    It can start as radiation, change into thermal energy, then into convective motion, then back into radiation, or any arbitrary combination of the above.

    The energy can also "bounce" back and forth between the atmosphere and surface multiple times, which is how the gross back radiation manages to be larger than the net solar input. It represents the "same" energy moving back and forth between atmosphere and surface.
  2. RW1, you are trying to partially correct that incorrect diagram and are not succeeding. "A" in that diagram is just the portion of the 385 outgoing IR absorbed by the atmosphere. It is missing the heat transfer from incoming solar (78), thermals (17), latent transfer (80).
  3. No one has yet to answer my question:

    If 239 W/m^2 of the total power of 396 W/m^2 at the surface isn't coming from the post albedo power from the Sun, then where is it coming from?
  4. Eric,

    "RW1, you are trying to partially correct that incorrect diagram and are not succeeding. "A" in that diagram is just the portion of the 385 outgoing IR absorbed by the atmosphere. It is missing the heat transfer from incoming solar (78), thermals (17), latent transfer (80)."

    Show me the power in = power out calculations.
  5. RW1>If 239 W/m^2 of the total power of 396 W/m^2 at the surface isn't coming from the post albedo power from the Sun, then where is it coming from?

    Did you read my earlier post? The 396 represents the "same" power bouncing back and forth between the surface and the atmosphere. All of that energy comes from the sun. You're trying to compare gross internal exchanges with the net input at TOA, it's apples and oranges.
  6. RW1,

    I want to make sure this is clear: every single Watt in Trenberth's diagram comes from the sun. You cannot differentiate between what portion is or isn't from the sun, because it is all from the sun. The reason you see numbers larger than the net solar input, is because the energy can move back and forth multiple times within the system, inflating the gross internal numbers. This is the essence of the greenhouse effect.
  7. e,

    "Did you read my earlier post? The 396 represents the "same" power bouncing back and forth between the surface and the atmosphere. All of that energy comes from the sun. You're trying to compare gross internal exchanges with the net input at TOA, it's apples and oranges."

    How do you figure? Is not 239 W/m^2 from the Sun less than 396 W/m^2 at the surface?
  8. RW1 (#353), the 396 in your post is not "total power at the surface" it is just the radiated power. It is missing the other transfers. KR showed the power equation in #327
  9. e,

    "I want to make sure this is clear: every single Watt in Trenberth's diagram comes from the sun. You cannot differentiate between what portion is or isn't from the sun, because it is all from the sun. The reason you see numbers larger than the net solar input, is because the energy can move back and forth multiple times within the system, inflating the gross internal numbers. This is the essence of the greenhouse effect."

    What's your point?
  10. RW1,

    I am explaining to you how the gross radiation emitted by the surface can be greater than the net input from the sun, even though there are no other sources of energy other than the sun. Did my explanation make sense or no?
  11. Eric,

    "RW1 (#353), the 396 in your post is not "total power at the surface" it is just the radiated power. It is missing the other transfers. KR showed the power equation in #327"

    No, 396 W/m^2 is the total power at the surface. The "total power" at the surface is same thing as the radiated power at the surface (so is the "power flux"). If it wasn't, the temperature could not be 289K.
  12. e,

    "I am explaining to you how the gross radiation emitted by the surface can be greater than the net input from the sun, even though there are no other sources of energy other than the sun."

    We all know this already.
  13. RW1 >396 W/m^2 is the total power at the surface ... If it wasn't, the temperature could not be 289K.

    No total power is total power, it includes radiation as well as convective heat transfer. Stefan-Boltzmann only applies to thermal radiation not to power in general. Thus, the temperature estimate does not change, as you are deriving it only from the radiative component of total power.
  14. "No, 396 W/m^2 is the total power at the surface. The "total power" at the surface is same thing as the radiated power at the surface (so is the "power flux"). If it wasn't, the temperature could not be 289K"

    RW1, that is simply incorrect. The total power flux (or heat transfer) from the surface is the radiated power plus conducted power producing thermals, plus latent transfer from evaporated cooling. As you agreed in #346, the earth conducts heat to the atmosphere. That has to be added to the radiative transfer to get the total.
  15. RW1,

    You asked us how power at the surface could be larger than power input from the sun, I answered your question, did you understand my explanation or not?
  16. e,

    "No total power is total power, it includes radiation as well as convective heat transfer. Stefan-Boltzmann only applies to thermal radiation not to power in general. Thus, the temperature estimate does not change, as you are deriving it only from the radiative component of total power."

    There is no distinction between "thermal radiation" and power - they are one in the same. Thermal radiation is measured in W/m^2, which is an equivalent power.
  17. e,

    "You asked us how power at the surface could be larger than power input from the sun, I answered your question, did you understand my explanation or not?"

    No, I asked how 239 W/m^2 of the surface power cannot be be from the Sun?
  18. RW1 - You make a curious statement here:

    "There is no distinction between "thermal radiation" and power - they are one in the same"

    I suppose I should now junk my car (thermal expansion power from exothermic reactions, not to mention thermal conduction to convective cooling at the radiator) and electric razor (electric power), as they cannot use energy to accomplish work???

    You're wandering very far afield. Power is the net movement of energy accomplishing work. Temperature is the result of energy sitting still (present in an object as molecular motion).
  19. RW1,

    Ok, you're just being obtuse, and I doubt you are here for serious conversation. If you can't be bothered to look up the definition of power, then this conversation is pointless.
  20. Eric,

    "The total power flux (or heat transfer) from the surface is the radiated power plus conducted power producing thermals, plus latent transfer from evaporated cooling. As you agreed in #346, the earth conducts heat to the atmosphere. That has to be added to the radiative transfer to get the total."

    Why do you think this? The 396 W/m^2 power flux at the surface already accounts for the thermals and latent heat transfer - that is why the diagram shows them in the atmosphere away from the surface and not at the surface.

    If there was no conduction and convection, the surface would be warmer than it is - over 30 C (396 + 17 + 80 = 493; 493 W/m^2 = 305.4K).

    Does this clarify things?
  21. "The 396 W/m^2 power flux at the surface already accounts for the thermals and latent heat transfer - that is why the diagram shows them in the atmosphere away from the surface and not at the surface."

    So you believe that the S-B formula accounts for evaporative cooling and conduction? There are no applicable factors in the formula to account for those. It determines radiation only.

    Ok, archiesteel was right, (110, 120, 134, ...). The fact is, RW1, that you didn't show us your incorrect website until post 150. Lesson learned for me: read the offending website completely, determine the most basic errors, don't go on tangents, don't allow tangents, and keep my promise to stop responding.
  22. Eric,

    "So you believe that the S-B formula accounts for evaporative cooling and conduction?"

    No.

    "There are no applicable factors in the formula to account for those."

    Correct.

    It determines radiation only."

    No, the S-B formula determines the equivalent temperature at the surface from the total power at the surface (and vice versa).
  23. Eric, re 302

    A is simply the radiative input from the surface to the atmosphere. The atmosphere then radiates this absorbed power up and down according to the laws of BB radiation. Is it your contention that a heated gas does not radiate as a black body?

    Also consider that evaporation/precipitation is a closed loop which redistributes energy from the tropics to the poles. Why is this any different than an oceanic or atmospheric circulation that does the same thing? You must keep in mind that a portion (albeit small) of the planets thermal mass is in the atmosphere and that circulation currents are what move energy around the entire thermal mass, including between the oceans and the atmosphere (actually clouds).
  24. Eric, re #208 #211

    The Ps and Pc values come from the raw ISCCP data. These are converted to surface and cloud top temperatures with a lookup table implementation of SB. The ISCCP defines the surface to be an ideal BB radiator with an equivalent temperature, but since in the IR, the Earth is nearly a perfect BB radiator, this is a good approximation and SB exactly defines the relationship between radiated power and equivalent temperature. Pw is generally small, but is the power converted by the Carnot engine driving weather into the work of weather. It may actually be 0 in the steady state, where the energy driving weather nominally comes from the latent heat of evaporation.

    The seasonal variability of the gain has more to do with seasonally variable surface reflectivity than anything else. The 1.6 value is a yearly average, so any seasonal gain variability averages out.

    The bottom line is that it takes 16 W/m^2 of incremental surface power for a 3C rise in surface temperature. Of the 3.7 W/m^2 of incremental absorption from doubling CO2, 1.9 W/m^2 actually affects the surface. This requires an average amplification of over 8. While the peak at the poles can even exceed 8, the average is all that matters relative to the long term effect of doubling CO2. The only way to reconcile this discrepancy is to treat power from GHG absorption as being many times more powerful at affecting surface temperatures than power from the Sun. Obviously, I can't accept this.

    A view of the gain as a scatter plot is here.

    http://www.palisad.com/co2/gf/st_ga.png

    The convergence of the surface gain to 1.6 is quite clear. Some of the higher gain values at the poles are the result of accounting for power transferred from mid latitudes, which tends to push mid and lower latitude gains down. While this appears to be a criticism of L&C, from the scatter plot, the average behavior of each 2.5 degree slice of latitude (green and blue dots) shows a very consistent interpolation between the equator and the poles. Note that for display purposes only, the individual gain data points were truncated to 12.
  25. 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.
  26. 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.
  27. 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).
  28. 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.
  29. 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.
  30. 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.
  31. 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.
  32. 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)
  33. 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.
  34. 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.
  35. 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.
  36. 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.
  37. 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?
  38. 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.
  39. co2isnotevil - "Can you describe the physical mechanism for how a thermal will influence the radiative balance?" Yes. See the posting here.
  40. 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?
  41. 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.
  42. KR, re 389

    I refer to to post 387 which disputes your point.
  43. 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.
  44. 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.
  45. 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.
  46. 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.
  47. 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.
  48. 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.
  49. 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.
  50. 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.

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