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Model-data-comparison, Lesson 2

Filed under: — stefan @ 10 April 2008

In January, we presented Lesson 1 in model-data comparison: if you are comparing noisy data to a model trend, make sure you have enough data for them to show a statistically significant trend. This was in response to a graph by Roger Pielke Jr. presented in the New York Times Tierney Lab Blog that compared observations to IPCC projections over an 8-year period. We showed that this period is too short for a meaningful trend comparison.

This week, the story has taken a curious new twist. In a letter published in Nature Geoscience, Pielke presents such a comparison for a longer period, 1990-2007 (see Figure). Lesson 1 learned – 17 years is sufficient. In fact, the very first figure of last year’s IPCC report presents almost the same comparison (see second Figure).

Pielke’s comparison of temperature scenarios of the four IPCC reports with data

There is a crucial difference, though, and this brings us to Lesson 2. The IPCC has always published ranges of future scenarios, rather than a single one, to cover uncertainties both in future climate forcing and in climate response. This is reflected in the IPCC graph below, and likewise in the earlier comparison by Rahmstorf et al. 2007 in Science.

IPCC Figure 1.1 – comparison of temperature scenarios of three IPCC reports with data

Any meaningful validation of a model with data must account for this stated uncertainty. If a theoretical model predicts that the acceleration of gravity in a given location should be 9.84 +- 0.05 m/s2, then the observed value of g = 9.81 m/s2 would support this model. However, a model predicting g = 9.84+-0.01 would be falsified by the observation. The difference is all in the stated uncertainty. A model predicting g = 9.84, without any stated uncertainty, could neither be supported nor falsified by the observation, and the comparison would not be meaningful.

Pielke compares single scenarios of IPCC, without mentioning the uncertainty range. He describes the scenarios he selected as IPCC’s “best estimate for the realised emissions scenario”. However, even given a particular emission scenario, IPCC has always allowed for a wide uncertainty range. Likewise for sea level (not shown here), Pielke just shows a single line for each scenario, as if there wasn’t a large uncertainty in sea level projections. Over the short time scales considered, the model uncertainty is larger than the uncertainty coming from the choice of emission scenario; for sea level it completely dominates the uncertainty (see e.g. the graphs in our Science paper). A comparison just with the “best estimate” without uncertainty range is not useful for “forecast verification”, the stated goal of Pielke’s letter. This is Lesson 2.

In addition, it is unclear what Pielke means by “realised emissions scenario” for the first IPCC report, which included only greenhouse gases and not aerosols in the forcing. Is such a “greenhouse gas only” scenario one that has been “realised” in the real world, and thus can be compared to data? A scenario only illustrates the climatic effect of the specified forcing – this is why it is called a scenario, not a forecast. To be sure, the first IPCC report did talk about “prediction” – in many respects the first report was not nearly as sophisticated as the more recent ones, including in its terminology. But this is no excuse for Pielke, almost twenty years down the track, to talk about “forecast” and “prediction” when he is referring to scenarios. A scenario tells us something like: “emitting this much CO2 would cause that much warming by 2050”. If in the 2040s the Earth gets hit by a meteorite shower and dramatically cools, or if humanity has installed mirrors in space to prevent the warming, then the above scenario was not wrong (the calculations may have been perfectly accurate). It has merely become obsolete, and it cannot be verified or falsified by observed data, because the observed data have become dominated by other effects not included in the scenario. In the same way, a “greenhouse gas only” scenario cannot be verified by observed data, because the real climate system has evolved under both greenhouse gas and aerosol forcing.

Pielke concludes: “Once published, projections should not be forgotten but should be rigorously compared with evolving observations.” We fully agree with that, and IPCC last year presented a more convincing (though not perfect) comparison than Pielke.

To sum up the three main points of this post:

1. IPCC already showed a very similar comparison as Pielke does, but including uncertainty ranges.

2. If a model-data comparison is done, it has to account for the uncertainty ranges – both in the data (that was Lesson 1 re noisy data) and in the model (that’s Lesson 2).

3. One should not mix up a scenario with a forecast – I cannot easily compare a scenario for the effects of greenhouse gases alone with observed data, because I cannot easily isolate the effect of the greenhouse gases in these data, given that other forcings are also at play in the real world.

363 Responses to “Model-data-comparison, Lesson 2”

  1. 251
    Jim Eager says:

    Tom, “the gavin” is Dr. Gavin Schmidt, one of the regular contributors and moderators of RealClimate and a research scientists at NASA’s Goddard Institute for Space Studies.

  2. 252
    Ray Ladbury says:

    John Finn, In order to attribute warming in the ’90s to increased insolation prior to 1940, you would have to explain how that energy could be stored in some heat reservoir that had no contact with the atmosphere from 1940-1980 and then suddenly dumped its heat contents into the atmosphere from 1980 to the present. Do you have a candidate for such a mechanism? Didn’t think so.

  3. 253
    Rod B says:

    Ike, #247 sounds very paranoid to me, though much of it could be true. (Paranoids can have people after them, too, you know.) Though I think GW per se, in many but maybe not all of your examples, is not the primary genesis for administration “censorship”. They don’t publicize the Pentagon’s military assessment on how to respond to GW for the same reason they don’t publicize our invasion of France plans. I can’t believe the Pentagon even wanted to — except maybe (and this is pure intuitive conjecture) they thought they might have latched onto something that would cause Congress to pony up lots more money.

  4. 254
    Tom Dayton says:

    Re: #190, #245, #252:

    In #252, Ray Ladbury wrote:
    John Finn, In order to attribute warming in the ’90s to increased insolation prior to 1940, you would have to explain how that energy could be stored in some heat reservoir that had no contact with the atmosphere from 1940-1980 and then suddenly dumped its heat contents into the atmosphere from 1980 to the present. Do you have a candidate for such a mechanism?

    John Finn and Barton Paul Levinson (BPL), I believe climatologists do have a decent idea of the Earth’s thermal response delay from a change in energy from the Sun, and it is way shorter than 50 years: Volcanic eruptions have caused sudden drops in received solar radiation, and the Earth’s thermal response has been measured.

    Perhaps some climatologists will correct me if I’m wrong. (I’m only a scientific research methodologist from another discipline. Who knew that climatology would become so exciting?)

  5. 255
    Martin Lewitt says:

    Re: Ray Ladbury #252,

    No energy storage would be required to explain the recent warming, by an increased insolation prior to 1940. I think you are misunderstanding, it is not the insolation prior to 1940 that could explain some of the recent warming, it is the fact that the increased level of insolation that was achieved prior to 1940 is continuing. There was an intervening cooling period. The recent response to that insolation level after the cooling event, is the response that would have occurred decades earlier had the cooling event not occurred. In fact the slope of the response may be greater than what would have occurred earlier, because some of the response that had already occurred prior to the cooling event may have been partially reversed. In other words the cooling event may have resulted in some loss of heat from the oceans.

    There are several time frames over which the weather responds to changes in solar forcing. Presumably some of the response over land is nearly instantaneous, as can be witnessed during large changes in total insolation such as during total eclipses, the night/day transition, and in the seasons at high lattitudes. But if the climate itself is to become warmer from the smaller variations in solar activity we observe, more than just the land must be brought along, since the thermal inertia of the oceans results in a moderating of the temperature responses. Most of the land temperature response occurs within the first few decades (unless that response is delayed by other cooling influences). This initial land response takes decades because the upper/mixing layer of the ocean has a couple orders of magnitude more thermal inertia than the atmosphere. The total response, and eventual elimination of the energy imbalance takes centuries to millenia because the deep ocean contains several times the thermal mass of even the mixing layer, and takes time to bring into equilibrium. In reality the climate is never in equilibrium, because something always changes, even orbital paramters change in less time than required to reach equilibrium. See the climate commitment studies of Meehl, et al, and Wigley, et al.

    The confusion caused by the increase in solar insolation prior to 1940 is really a canard. Because of the intervening cooling period, it might as well be as if the increase in insolation had just occurred in the 1980s. There is no heat storage required, although the heat stored in the oceans prior to 1940 might have delayed or moderated the start of the cooling. The continuing pleateau in 1940 level insolation might also have made the cooling less than it would otherwise have been. It is also possible that there was some level of global dimming in the climate system prior to 1940, and that the recent clearing of the atmosphere has resulted in a solar insolation/clear atmosphere combination that is higher than could possibly have occurred with the initial rise in solar activity.

  6. 256

    John Finn asks:

    OK, BPL, assuming all other factors had remained the same, when do you think the warming from the increase in solar activity would have leveled off – bearing in mind that the solar peak was actually in the late 1950s (rather than 1940). And do you think that the warming would have continued at the pre-1940 rate.

    The point is, the warming would have started out rapid and gradually declined. It would not have done what it actually did, which is to grow slowly for 20 years and then accelerate sharply for the last 30.

  7. 257
    Ray Ladbury says:

    Martin Lewitt, I have never seen a physical system with a delayed response of this type. Think about it. It implies that warming is delayed for >40 years and then suddenly accelerates. Can you suggest a differential equation with this behavior–let alone a physical mechanism?

  8. 258
    John Finn says:

    The point is, the warming would have started out rapid and gradually declined. It would not have done what it actually did, which is to grow slowly for 20 years and then accelerate sharply for the last 30.

    It would if some other factor was damping the warming in the first 20 years. Try plotting PDO data over the last 70 years or so and note the timing of both the cool and warm phases (Hint: they’re in the 1940s and 1970s respectively)

  9. 259
    John Finn says:

    Re: #256

    The point is, the warming would have started out rapid and gradually declined. It would not have done what it actually did, which is to grow slowly for 20 years and then accelerate sharply for the last 30.

    It would if some other factor was damping the warming in the first 20 years. Try plotting PDO data over the last 70 years or so and note the timing of both the cool and warm phases (Hint: they’re in the 1940s and 1970s respectively)

    Re: #257

    You plot it as well, Ray.

  10. 260
    John Finn says:

    Re: #257

    Can you suggest a differential equation with this behavior–let alone a physical mechanism?

    Pacific cooling? See my response to BPL.

  11. 261
    trrll says:

    I suspect that we don’t really understand the mid century cooling event. It was a time of significant aerosol and particulate pollution, three major conflicts WWII, Korea and Vietnam, open air nuclear testing, leaded gasoline, etc.

    So rather than a greenhouse effect with reasonably well-understood physics, you propose an increase in solar output, which to account for the degree of warming must be unprecedented over the period of history for which we have good temperature records (Do you have any actual evidence for this?). Moreover, to match the temperature record, the warming effect must have been largely masked by a transient cooling effect of unknown origin, fortuitously providing kinetics that just happen to match that predicted by physical models that incorporate greenhouse warming? Do I have your hypothesis right?

  12. 262
    Martin Lewitt says:

    Re: Ray Ladbury #256,

    A differential equation is not needed, “a” delay in the response to the new level of solar forcing that would ordinarily have resulted in some warming, could be caused by an intervening period of negative aerosol forcing. Just because solar activity is at a high level does not mean that aerosols cannot cause cooling or at lower levels a moderation of the warming. When the aerosols are reduced, the response to the warming can now occur that would have occurred earlier, if not for the aerosols.

    For a more physical example of how a period of negative forcing can result in a period of cooling, consider room temperature water in a container, placed upon a burner. The burner is set to a new level of forcing say 9, but before much temperature response, a negative forcing of a bunch of ice cubes is added, enough so that the temperature actually cools, even though the new level of burner forcing continues unabated. Hopefully, differential equations are not needed to see that there will eventually be a delayed response to the new level of burner forcing, in fact a response will occur even if that new level of forcing is only maintained above the original level of forcing that the water was subjected to, i.e., say the burner forcing drops to 8. See, no storage of the heat from the burner is required.

    Having considered “a” delay, now lets consider “the” delay of interest. It is probably more complicated, but yes, aerosols may well be the source of some, most or nearly all of the negative forcing. If pollution was the cause, undoubtedly there was also some positive forcing from some of the particulates, but the net forcing was negative. As I stated, I am also curious about the particular characteristics of the particulates from this period of leaded gasoline use. I am also curious about the posssible cloud feedback effects from the radioactive tritium from the open air nuclear testing. The solar forcing itself may have also taken a slight dip in that periord. In any event, the full response to the new level of solar forcing could not take place until the intervening aerosol plus whatever event had taken its course. It may well be the negative aerosol forcing is lower in the 1990s and now than it was in the early 20th century when the new level of solar forcing was being achieved. The dirty phase of the industrial revolution was already well underway.

  13. 263
    Ike Solem says:

    Martin Lewitt,

    You seem very certain. Do you know what the reduction in solar irradiance (the sum of changes in diffuse + direct radiation) was following Pinatubo? Just a percentage?

  14. 264
    Ray Ladbury says:

    Martin, the level of solar forcing you are assuming is precluded by a variety of data, including (as Ike implied) data for Mt. Pinatubo. Solanki has visited this in detail. Solar forcing could account for at-most 50% of warming post 1900, and that is at the outer extreme.

  15. 265
    Martin Lewitt says:

    Re: Ike Solem #263,

    I don’t know what the reduction in solar irradiance reaching the surface from the Pinatubo was, but it would have to be a small percentage, since the total irradiance from the Sun is large enough to raise the surface temperature of the earth above the cosmic backgroud temperature, which is, about 3 degrees K or so, if I recall correctly. If you know the percentage, it might be helpful to translate it into a percentage of that portion of the solar radiation that is in excess of that required to raise the global temperature above the freezing point of water. That might help give it more familiar perspective since we live in the regime of liquid water. Lets be wary of getting too linear in our thinking however.

    I am pretty certain, certain that we don’t know as much as we’d hope, and that more has passed peer review, than perhaps should have. We don’t know whether most of the recent warming is due to AGW. We’d like to know, and the statement might be true, but the current uncertainty in solar forcing and coupling, and in the models is such, that most of the warming might instead of be due to solar activity. It is a hypothesis made plausible by the usually high level of solar activity. It would seem physically impossible for it not to be a significant contributer, but whether that is as small as 20 or 30%, or is much larger, we must await better models, and the data with which to validate them.

  16. 266
    Martin Lewitt says:

    Re: Ray Ladbury #264,

    If you are referring to Solanki’s 2003 paper “Can solar variability explain global warming since 1970?”. It tries to explain the possible contribution of solar variation since 1970 to warming since 1970, based on the assumption that the warming prior to 1970 was due to solar variation since the maunder minimum.

    I can agree that solar variation since 1970 explains only a small part of the warming since 1970, and his maximum estimates for this are probably too high as he would hope given his conservative assumptions. He was trying to assess the maximum possible contribution.

    That said, he is ignoring climate commitment, the time lag due to the thermal inertia of the oceans, and his assumption that solar variation is responsible for all the variation before 1970 is less favorable to solar than it might have been. By 1970 the midcentury cooling event was well underway, and probably reflects a strong aerosol and other negative forcing. He might have obtained a better sensitivity to solar by using explaining the temperature increase prior to 1940 instead, and using a solar forcing series that ended 10 or 20 years earlier. Even that correlation/sensitivity would only explain a small part of the post 1970 warming as due to solar variation since 1970. If one only considers variation since 1970, to explain the temperature record since 1970, then most of the recent warming would have to be attributed to AGW, and a reduction in negative aerosol and other forcings. The contribution of one of the highest levels of solar forcing in the last 8000 years to one of the warmest climates in the last 8000 years, would be mostly revealed within the reversal of that negative forcing, since arguably much of this warming would have been achieved 45 to 50 years earlier if not for the cooling event.

    Since the cooling event is over, there is an energy imbalance that will be reduced ( perhaps even eliminated, or reversed) when solar activity returns from this statistically unusually high level. It is in that sense that some unknown amount of the recent warming should be attributed to solar. If solar activity were at an average or low level the argument that it is responsible for some of the energy imbalance would not be nearly as strong, and would probably not be made. This energy imbalance represents the climate commitment to further warming, even absent any further increase in external forcings. We need to know the relative contributions because GHGs are likely to increase and solar activity is likely to decrease.

  17. 267
    Ike Solem says:

    Martin, you will want to look first at Figure 9.3, Chapter 9 (attribution and detection) of the 2007 IPCC report:

    “Comparison of outgoing shortwave radiation flux anomalies (in W m–2) after Pinatubo”

    As well as Changes in solar radiation fluxes after the Pinatubo eruption (1994)

    “Measurements at a high mountain station on cloudless days showed significant changes in solar radiation from summer 1991 to summer 1992 as a consequence of the Pinatubo eruption. An increase in diffuse sky total radiation and a concomitant decrease in global total radiation (sun and sky) of 4% were observed. The optical aerosol depth at 427nm, obtained from sun photometric measurements, showed a significant increase.”

    So that is a change in solar radiation received at the surface. Changes in solar radiation result in immediate cooling of the land and the ocean surface layer. For a good science article on this and Pinatubo cooling, see New Scientist: Pinatubo cooling will test greenhouse models, 11 January 1992

    For a discussion of how quickly ocean temperature responds to changes in solar forcing, see Church et al (2005) Significant decadal-scale impact of volcanic eruptions on sea level and ocean heat content, nature (pdf)

    However, you are saying that early twentieth century increases in solar forcing are only being seen now, right? Even though such increases were fairly minimal? In any case, if you look at Figure 1 of Lockwood & Frohlich, you see that the recent solar forcing is at the very minimum of the 11 year cycle – according to Sallie Baliunas and Willie Soon in the late 1990s, who seem to be where you get your material from (, we are supposed to be cooling off right now as a result – but that’s not the case, either. To quote L&F’s conclusion:

    There are many interesting palaeoclimate studies that suggest that solar variability had an influence on pre-industrial climate. There are also some detection–attribution studies using global climate models that suggest there was a detectable influence of solar variability in the first half of the twentieth century and that the solar radiative forcing variations were amplified by some mechanism that is, as yet, unknown.

    However, these findings are not relevant to any debates about modern climate change. Our results show that the observed rapid rise in global mean temperatures seen after 1985 cannot be ascribed to solar variability, whichever of the mechanisms is invoked and no matter how much the solar variation is amplified.

  18. 268

    tom watson #174: you asked me and others where the extra energy has gone. Read some of the other comments on this page. You are keen on bringing latent heat into the picture. Find some numbers on the quantity of ice that’s been melting in recent years and work out how much energy that has taken. Also, there are exchanges between ocean and atmosphere: El Niño and La Niña are larger-scale phenomena, but this is happening to some extent all the time.

    As for ocean temperature, here‘s an interesting article to contemplate.

  19. 269
    Chris Colose says:

    #221 Timothy Chase

    It looks like addition of greenhouse gases are playing a larger role in strat. cooling than ozone depletion. Eli has a good post at

  20. 270

    Martin Lewitt writes:

    the current uncertainty in solar forcing and coupling, and in the models is such, that most of the warming might instead of be due to solar activity.

    This may be what you want to believe, but there’s no objective evidence for it.

  21. 271
    Lawrence McLean says:

    Has there been any work done with regard to processing the temperature records in order to reduce the “noise” in the resulting average temperature records? An example of the process that I am asking about, is this:
    Identify periods of equal (or very close to) sea surface temperature for the major Oceans. Then, choosing the oldest period as the baseline, determine the temperature anomolies in the affected land areas for each of the subsequent periods of equivalent sea surface temperture. It would be interesting to see the results of this sort of work.

  22. 272
    tom watson says:

    Re Jim Eager @ 143:

    I missed this comment earlier and was reading again and came to it. I don’t know how one adds the bar indent to highlight and earlier comment. So I do my best.

    Jim Eager claims “H2O does indeed have a much lower scale height than CO2.”
    I don’t have any idea what this refers too. I could speculate on something about altitude, but that seeds silly to me.

    I used the term blink of an eye, well one could also use nanoseconds. The point is that from every emission and re-emmission some percent of the black body radiation is gone in a nano second. Yes CO2 and H20 absorb a subset of wavelengths, and converts the energy into the heating of all the billions of air molecules including the very few CO2. On clear night in a dessert the air cools quickly, It generally cools by degrees per hour. It generally keeps cooling until the due point is reached and then the vast heat stored in H20 vapor is released as H20 vapor condenses to water or directly to ice.

    From such cooling delay as seen in the dessert, I do not see how C02 will delay cooling for a century or decades. I don’t see heat being stored for day after day. It seems those who thing CO2 is the 20% GHG as that is it’s effect if no H20 was present cannot explain why does the dry desserts with the lowest H20 cool the fastest over night.

    Jim, this is my belief, my theory, my minds eye visualization of what is happening.

    There is the solid earth, It emits a flux of black body distribution(bbd) photons. The direction is in some random or semi random half sphere that is normal to the local surface. I use the idea of a sphere as they are not all emitted up through the least amount of atmosphere.

    For common termperature.
    The flux of the earth per unit area x by x is far far greater than any volume of air x by x by x. The flux of a volume of air or a point in the air sends photons in a full sphere of directions. What is the surface to volume ratio? Also remember the surface is not flat except at near atomic scales. What is the true atomic surface area of a cm^2

    For certain wavelength photons, H20 CO2 and molecules other are like radia antenna and are tuned to that photons wavelength such that under some conditions of there paths crossing, the ergs of the photons is adsorbed by the molecule and it vibration or temperature is increased. This temperature vibration is transferred or averaged to the several hundred molecules that surround each CO2 or H20 molecule.

    If a photon is, then it’s energy is not heat and until is gets adsorbed it is just nano seconds away from space and out of any possible contribution to the temperature of the earth.

    I have read articles and there is proposed that for CO2 concentrations the wavelengths where CO2 could adsorb would occur within 10 meters. One can argue, 10 or 20 or 100. But even that I believe does not consider the random direction of emission that would greatly reduce the amount of progress photons make in reaching space and freedom.

    Now for every altitude as it increases photons are emitted in all directions. But as we go higher in altitude there are fewer molecules above and more molecules below. For every photon there is a direction and a wavelength and based upon those factors there is a probability of a nano second escape or absorption atmosphere or absorption earth.

    As one goes higher the number of directions that I would describe as a cone increases, different amounts for each wavelength that have a 99% probability of nano second escape. The same is occurring for a cone that describes the probability of a photon hitting the earth. That cone is decreasing as we go higher in altitude.

    The convection stream, All heat that is in matter on the earth and in the atmosphere is in the convection stream. Gravity drives the convection stream and it move heat by currents toward altitudes where 99% of photons will get nano escape. The convection stream and the radiation stream are working in series and in parallel. Energy is constantly moving between them. But if CO2 were delaying heat, it would be stored somewhere in the convection stream and the recent very cold few years show no stored energy. Somewhere I read of some robot subs sampling ocean temps and no heat is found.

    CO2 warming science says C02 somehow increases the delay of heat transfer to the altitude where 99% of photons will get nano escape.

    The current ratio of CO2 to the far more numerous H20 and the properties of HO2 in heat transport in the convection stream simply makes the CO2 global warming suppositions to be nonsense.

    Now as to where is the heat waldo..

  23. 273
    Ike Solem says:

    Tom, I wonder if you really want to learn anything, but try this:

    If you are out on a cold, still night and you wrap up in a cold blanket, why do you feel warmer? What would you look like to someone watching you through an infrared viewer as you put on the blanket? You would feel warmer, but to the external observer your body temperature would have suddenly decreased as you wrapped the blanket around you.

    That’s the Earth at night when no solar energy is incident. That’s also why it stays warmer along coasts at night than in the desert – there’s more water vapor in the air along the coast, and water vapor like CO2 absorbs infrared heat and reradiates it in all directions, including back to the surface.

    Now, think of the earth as you, the blanket as the heat-trapping infrared-absorbing gases, and the external observer as the scrapped Triana/DSCVR satellite that should have been placed at L1 (a stable gravitational point directly between the sun and the earth), but wasn’t because of lobbying efforts by people who didn’t want data on global warming collected… and there you are.

    It’s called insulation. By increasing the atmosphere’s content of long-lived greenhouse gases (mainly CO2, then methane, then N2O – 10 to 100+ year lifetimes), we warm everything a little – and this helps more water vapor into the atmosphere (1-2 week lifetime) – and that all results in a net thickening of our atmospheric blanket.

    Hope that helps.

  24. 274
    Ray Ladbury says:

    Tom, #272 has to be the vaguest mass of gobbledygook masquerading as science I have ever read. On the one hand, you seem to be arguing that CO2 can’t possibly absorb very much energy because there isn’t enough of it. On the other hand, you seem to be arguing that all of the radiation that can be absorbed is absorbed within 10 meters of ground level–i.e. that CO2’s effect is saturated. Which is it? Here’s a hint. CO2 molecules can both radiate and absorb IR. Think of it in terms of equilibrium between radiant energy and kinetic energy. If you have equilibrium, energy radiated = energy absorbed. But initially, you have more radiant energy than kinetic, so some of that energy must be absorbed and converted to kinetic energy (i.e. it stays in the climate system). OK, but each of those CO2 molecules can also radiate, and the energy that propagates upward is rising into an ever colder sky–again, more photons than can be sustained at equilibrium, so you get more absorption, and so on, and so on. More CO2 means more absorption at ever higher and colder altitudes, so less and less energy in the critical band escapes. In addition, the line broadens as CO2 concentrations increase.

    Don’t think that there’s enough energy to warm Earth in that line? Sit down and do the math–it’s not that hard. Start with a blackbody spectrum from Earth’s surface and look at how much energy is in that absorption line. It ain’t chicken feed.

  25. 275
    John Finn says:

    Re: Solar + PDO amplification/damping

    Has anyone plotted the PDO record yet?

  26. 276
    tom watson says:

    re; 273 ike solem, Well what you say is true in terms of the observations. But also one could measure the heat that was mechanically delayed from conduction and convection and radiation. Also the time constants of seconds or hours and the observations do not dictate a connection with time scales of millions of seconds and tens of thousands of hours.

    All opinions on the effect of more or less CO2 in the earth’s atmosphere comes down to supposition on how all the complex interactions result in a manifestation of a warmer of colder global temperature(s).

    I have spent thousands of hours looking for real science or reason that explains what I see, or experience and together with what is measured show a clear relationship of cause and effect. On this real site the discussions of past 650,000 years of proxy estimated CO2 concentration and proxy estimated global temperatures don’t show and or don’t mention CO2 lags temperature by several centuries and when they do mention it they speculate pontificate that CO2 with it lagging increase somehow spurred increased temperatures. I wonder is that cause and effect science or wishful thinking or?

    I believe now and in the past the escape of heat from the earth has aways been dominated by convection streams. And some stream are involved in cycles that for years, sometimes centuries change the sum of daily, monthly and annual cycles and in the convection stream H20 is the 99.9% energy storage and transporter. (OK maybe H2O is not 99.9, but CO2 is some micro or nano or pico part in an absolute or relative part) I see no evidence that CO2 is other than a bit player having no consequence in the scale of h20. This because of the respective masses of each, the 300 time specific heat tranfer of h20 over CO2. and the fact that h20 also has the property of creating lighter air with humidity that carries heat up and then releasing heat in fusion h20 in effect vanishes in volume or partial presure reducing further the density of air.

    If CO2 is constantly heating all a little, where is the little heat from last year and the year before …. etc…
    Again this is a summation record.
    This show what IPCC says is WHAT MODELS predict as a signature of CO2’s heating. Also is a shot of what a satellites have really seen.
    (please excuse the whimsical editorial comments within this image. I am certain the author means no disrespect or insult to all learned posters at )

  27. 277
    Hank Roberts says:

    > CO2 lags temperature

    > heat from last year and the year before

    The equilibrium of Earth in absorbing and emitting radiation is explained …

  28. 278
    Hank Roberts says:

    > I believe …. the escape of heat has aways
    > been dominated by convection streams.

    Objects in a vacuum can only get rid of heat through radiative heat transfer….

    … An object at a constant temperature is receiving heat just as fast as it is getting rid of it. This is called “thermal equilibrium”.

    An object at equilibrium can still have a thermal gradient. Shine a bright light on an object. The side facing the light will be heated by radiative heat transfer. The shaded side will still be cooler.

  29. 279
    Ike Solem says:

    “I believe now and in the past the escape of heat from the earth has aways been dominated by convection streams.”

    Okay, you need to go back and read 19th century science, I’m afraid. Try starting with Maxwell’s “Theory of Heat” where you will find an accessible but stilted explanation of convection, radiation and convection. Wikipedia has a good overview at – but the entire book is in the public domain and is also online.

    “If CO2 is constantly heating all a little, where is the little heat from last year and the year before?”

    Well, it warms the oceans – but slowly – but we do see the oceans steadily warming (they take up ~9/10ths of the total energy imbalance, and the the rest goes to warm the atmosphere, mostly, as well as to evaporate water – thus the secondary increase of atmospheric water vapor). As the ocean warms, many other things will change, such as ocean circulation patterns – but exactly how is an issue that is still poorly understood.

    Some of it also escapes to space – via radiation, not convection.

  30. 280
    David B. Benson says:

    tom watson (276) — From the analysis of the Vostok ice core by Petit et al., it is easy to see that at the climatic opitmum of the Eem (Eemian interglacial), CO2 concentration and temperature went hand-in-hand, within a one hundred years or thereabouts.

  31. 281
    Joe Hunkins says:

    … the model uncertainty is larger than the uncertainty coming from the choice of emission scenario …

    OK, but at what time frame does the model under scrutiny become subject to a reasonable degree of falsifiability? What Pielke seems to be suggesting in many of his critiques is that modellers are very reluctant to set up criteria that would allow a reasonable observer to reject the the model.

    I’ve read dozens of RealClimate posts but find no discussion of what observations would make various modelling assumptions break down. What warming/cooling data should lead one to reject the AGW hypothesis? If the answer is “nothing observable would do that”, then Houston, we’ve got a problem.

    [Response: There isn’t a fixed time. It depends on the signal to noise ratio which will be different for each metric. For instance, for the mean global temperature the expected signal comes out of the noise in around 10 to 15 years, in the tropics it’s probably longer (bigger noise, smaller signal). But you have a basic mis-conception at the heart of your question – there is no single ‘AGW’ hypothesis. GHGs are undoubtedly increasing because of human activity, the fact that they are greenhouse gases is known from laboratory experiments, and it is indisputable that increasing GHGs will warm the planet all else being equal. So what you are left with is uncertainty in the magnitude of the response and the strength of the various feedbacks and their impacts. But that isn’t one thing – and it’s a lot harder to distinguish between a 2 deg climate sensitivity and a 4 deg climate sensitivity. We have already been able to dismiss the hypothesis that it is much smaller than that, though the upper limit isn’t as well constrained. That is the problem, Houston. – gavin]

  32. 282
    Ray Ladbury says:

    Tom Watson says, “I have spent thousands of hours looking for real science or reason that explains what I see, or experience and together with what is measured show a clear relationship of cause and effect.”

    Uh,… right. Tom, it is clear from your posts that you haven’t devoted 30 seconds to thinking about the real science. Look, Tom, the science that nearly all the experts have developed is summarized very nicely here and in the pages linked under “Start Here”. Why not devote a week–just one week of your life–to learning that science. I’m not promising that it will convert you, but at least you will have a vague idea how to frame your arguments against it. Because right now, when you argue that convection is the dominant mechanism for heat to escape Earth–an isolated system surrounded by at least 375000 km of vacuum–well, it doesn’t exactly do much for your credibility.

  33. 283
    tom watson says:

    Dear Ike Solem re 279, I suggest you reread my entire posts, I suggest you do not quote a single sentence out of it’s context and then make a suggestion someone go and read history. Maybe that’s too harsh. I wrote two posts and in the first I gave explanations. the ideas of both were connected in my mind, but that does follow in the context of two separate messages.

    I believe now and in the past the escape of heat from the earth has aways been dominated by convection streams.” Yes the final escape of heat from the earth is from radiation. But how that heat get’s absorbed and transported by instant radiation or radiation then absorption from surface to some point where it radiates and escapes is about the times delays of storage of that heat is heat. heat being stored and transported in convection streams. All around earth heat radiates and escapes or is adsorbed and enters the convection stream. There are daily radiation and convection streams, annual and longer.

    One can spend all kinds of time attempting to explain, but CO2 warming is only a supposition that some believe as their computer models have said when it’s all added up, this is what happens. But now with the cheapness of computers, gigaflop home computers and anyone having the availability of great visualization, even the scientific lesser strings can take data tools and create a picture of what the models project. It is not rocket science at all.
    And this figure shows what all the science experts who created the models predict for the signature of CO2 based global warming. And does the figer print agree with reality of measurements. You be the judge.

  34. 284
    Ray Ladbury says:

    Tom Watson–so you think that the climate models run by the IPCC are run by amateurs with a political agenda? All I can say is “Wow!” Would you even recognize reality if it passed you on the other side of the street?

  35. 285
    tom watson says:

    Dear Hank, re 277 278,

    about convection being a dominate player is heating or cooling, read my other posts.

    The links you pointed to. samo samo hand waving nonsense. no science, just speculation presented as God speaks. when will the cliff notes be available.

    But Hank, consider this visualization from the IPCC latest climate report.

    Now from what I have read of all the experts on mighty CO2 and how it will destroy civilization by thermal runaway, this visualization of what models predict does make sense. Oh well my annotated version has the temp scale, better use that..
    The predicted almost 1 to 1+ degree heating over 60 degrees of latitude at 12 kilometers altitude would very likely cause more heat to be re-radiated back into tropical oceans and that would lead to the advection of more and more heat to temperate latitudes and make for some real global warming.

    But boohoo, no model predicted heating can be found. So what is the theory on how CO2 somehow is a mega player in slowing heat loss by radiation.

  36. 286
    Hank Roberts says:

    Tom, see the “Start Here” link at the top of the page, and the first link under Science at the right hand side.

    Also you’ll find using the Search box at the top of the page, to search this site, helpful to save asking questions already answered.

    Anyone up for recreational typing can repeat at greater length.

  37. 287
    Phil. Felton says:

    Re #276

    “I believe now and in the past the escape of heat from the earth has aways been dominated by convection streams.”

    No it hasn’t, without the GHGs the convection in the atmosphere does nothing for the heat loss.
    Increasing GHGs will change heat loss without there being any change in convection.

    “(OK maybe H2O is not 99.9, but CO2 is some micro or nano or pico part in an absolute or relative part) I see no evidence that CO2 is other than a bit player having no consequence in the scale of h20.”

    Since the key properties of CO2 as far as GHE is concerned is its absorption and emission of a particular range of IR radiation, its relative concentration with respect to another component of the atmosphere which doesn’t absorb in that part of the spectra isn’t germane!
    Very small quantities of absorbers can have quite dramatic effects, for example

  38. 288
    tom watson says:

    Dear David B. Benson re:280,

    I don’t pay much attention to the meanings of ice cores. I believe I followed links to the actual data and the cores are sampled in century length times. So the the correlations have by definition huge century errors and as all data associations of thousands of inferred assumptions, the meaning can well be in the eyes of the beholder with a colorful Synesthesia.

  39. 289
    Timothy Chase says:

    Chris Colose (#269) wrote:

    #221 Timothy Chase

    It looks like addition of greenhouse gases are playing a larger role in strat. cooling than ozone depletion. Eli has a good post at

    As I said, above the lower stratosphere, yes.

    Please see:

    Uncertainty, noise and the art of model-data comparison, Comment #384

  40. 290
    John Mashey says:

    Of 285 posts so far, 45 (1/6 of the total):

    22 are by Tom Watson
    25 are by others replying to Tom Watson

    Those patient folks in the latter category might consider reviewing that sequence so far as a *whole*, and see if any ideas occur.

  41. 291
    Ray Ladbury says:

    John Mashey, I am afraid you are correct. I see no evidence that the learning curve has a positive slope.
    I believe that Tom’s comment asking when the cliff notes of the AIP History of Climate change might be available is particularly revealing. It shows he is not willing to invest any of his time to learn the real science. He is more interested in promoting his own silly-assed blog. Diagnosis: terminal trollism.

  42. 292
    tom watson says:

    re 261: Ray Ladbury, well ray if I have posted 22 times, how many of those 22 times have I taken time to attempt to explain as best I can what I believe and why I believe it. This is the first time I have decided to attempt posting at Now if you pass your mouse over my name, it has a link that I provided and that gives a small part of my technology background. I have also posted links to that is an open directory containing dozens of images, pdf and some html that I have acquired over the years. I run my own web server that is part of a compute and quad display linux cluster. I work on about a dozen task at a time. this is the basic 1994 design.
    this is 4 eyes, but sw1600 replaced now with samsumg 1600×1200 flats.

    For the record, I have no personal blog. I am looking for honest men of all seasons who are smart enough to explain without handwaving and God pontification or reference to sites they have never really understood themselves. Yes I troll for honest men of all seasons.

    Some only have the ability to count posts and make comments on others supposed inability. Such a fruitful use of one’s time. But they have not time and maybe no comprehension of science, so they express no scientific analysis or suppositions, just personal opinions on the lack of intelligence of others.

    When I read such, I smile. And wonder where does one find the heat stored as predicted by the models of the climate experts.

    [edit – enough repetition]

    [Response: With all due respect, you have been pointed to multiple sources of primary source material about subjects upon which you have incorrectly claimed knowledge. You have shown no interest in reading or comprehending them, and you insist on reposting over and again the same cherry-picked and misleading graphics. That is not the way to a fruitful dialog. If that is really what you want, get to the point! I have yet to discern any coherent criticism or question in your reams of comments. If you want to look at where the heat is stored, go to the latest ocean data. – gavin]

  43. 293
    Ray Ladbury says:

    Tom Watson, since I’m not interested in incoherent, pseudoscientific ramblings, I don’t think we have much to talk about until you actually bite the bullet and learn some of the actual science. People have vectored you to good sources. Should you have relevant questions, I’ll be happy to try to answer them.

  44. 294
    tom watson says:

    Dear gavin, I call the image I cobbled together a good summary. A picture is worth a thousands words they say. It is not cherry picked, it was published by the IPCC and I explained what I thought it meant and implied. You say it is misleading. Well I would like to know why or what is misleading.

    I also followed your link. I have followed all links given to me. Where I have been spending some recent free times is
    At this link I followed
    I read a conversation and I believe it says no heat has been found. There also is a chart showing ocean heat content doing the hockey stick. But so little is explained about the charts meaning and it shows data point in the future. So I would guess it’s just another supposition of what if. But in the dialog I find it repeated there has been no heat found.

    # The recent (last 4 years) upper ocean observations show no warming.
    # If heat is entering the deep ocean, it is, therefore, not contributing to an increase in sea surface temperature. This necessarily reduces the amount of water vapor evaporated into the atmosphere from what would occur if the heat were in the upper ocean.

    Also, if I were running any common forum of idea interchange, [edit – you aren’t, and please do not include personal comments]

    [Response: Please read the links again, specifically: “it does seem very likely to me that the 50-year trend in ocean heat content is part of the climate’s ongoing response to greenhouse forcing” – and “there are several multi-year periods when OHCA is flat”. Thus plenty of heat has ‘been found’ and interannual variability in its accumulation is to be expected. And who has ever claimed that heat storage in the deep ocean increases water vapour amounts? Feedbacks follow surface temperature, not heat storage. Strawman argument. – gavin]

  45. 295
    Phil. Felton says:

    Re #292

    “I taken time to attempt to explain as best I can what I believe and why I believe it.”

    And showed that your belief is based on a flawed understanding of the physical chemistry involved and that you resist any attempts to rectify your lack of understanding!

    “I am looking for honest men of all seasons who are smart enough to explain without handwaving and God pontification or reference to sites they have never really understood themselves.”

    Yet you don’t listen to them when they try to help you!

  46. 296
    Ike Solem says:

    The immediate conclusion is that tom watson is best understood as yet another example of a phenomenon well-described over at

    There is an interesting background here related to this post – because in the early 1990s, claims were that the models were overestimating the warming, and this led to a massive attack on modeling by the fossil fuel PR lobby, led by the likes of Patrick Michaels and Richard Lindzen.

    Now, the data is outstripping the model’s prediction in some areas – and all of a sudden the models are the things that the skeptics are clinging to! Thus, the lower bound of IPCC model results for sea level rise is now what the fossil fuel lobby are pointing to – not the data showing the rapid changes in the Arctic.

    It’s no secret that part of the fossil fuel PR effort involves hiring bloggers and internet commentators to push their talking points, or simply to disrupt discussions. Thus, it’s best to respond to such people by always including examples of the original topic of the post – model-data comparisons – in your reply.

  47. 297
    David B. Benson says:

    tom watson (88) — Wrong again. Here is the climatic optimum of the Eem from the Petit et al. analysis of Vostok ice core (date in years ago, ignore data with minus sign, then the temperature above the reference) (interpolated is the CO2 concentration data, with CO2 ranging from 274.1 ppm to 287.1 ppm):

    128259 -421.2 2.50
    128300 274.1
    128309 -419.4 2.78
    128357 -416.6 3.23
    128399 287.1
    128405 -416.9 3.16
    128453 -417.2 3.08
    128501 -417.2 3.06
    128549 -419.1 2.71
    128599 -421 2.37
    128650 -422.4 2.11
    128652 286.8
    128702 -423.7 1.87

  48. 298
    tom watson says:

    re gavin, Strawman argument. I have no idea what you claim is any Strawman argument I have proffered. If CO2 changes the balance of heat loss, by all laws of physics I know, that heat must be somewhere. Oceans are the only thing I can think of that have the mass with the specific heat, to hold said heat. The cherry pick of the IPCC supposed fingerprint of CO2 warming, the visualization of the models that have CO2 causing that heat to be stored are like the murder weapons and bullets linked to a victim. You say I’ve claimed knowledge of things I don’t really understand. I saw the IPCC visualization.
    I interpreted it’s possible implications. If what I saw existed I can fathom how CO2 could be radiating back heat into the oceans. But real world measurements found nothing like what models predicted. Or what a visualization of what models predicted.

    All comment, all the links provided me have statement of the form “it does seem very likely to me that the 50-year trend in ocean heat content is part of the They are opinions, they are not science fact and they do not explain the science.

    The predicted heating of the 12K altitude has not been found. Makes sense that one would also not find heat in the ocean for the last few years that have been depicted as colder by the data plotted in this chart.

    Now in the links I have provided, any interested person could find a lot about my work experience and interests. Assuming they are not fabrications, they would imply or suggest I have some knowledge and understanding or science, engineering and the use of such knowledge in creating solutions to problems.
    And the wise know, you cannot solve problems that you do not understand.

    It turns out that in my previous work history, I have done real genuine nuts and bolts rocket science. I was no expert at the start, but I provided the complete software design and implementation so NASA could be certain that solid rocket boosters used on the Space shuttle were bolted together with a very balanced loading to prevent nasty leaks. What does that have to do with global warming? As much as CO2.

    My personal comment was to you and in that you have the power to edit, I saw no problem. In every response on all matters, one learns about whomever speaks.

    [Response: Well, learn then: The icecap graph is a cherry-picked time period and misleadingly scaled to boot – yet you have posted the link multiple times; The vertical profile of tropospheric heating particularly in the tropics is quite noisy and has many issues in the data – yet you think that the analysis is being done by ‘idiots’. Try instead reading some of the latest literature on the subject – I think you’ll be surprised: Lanzante and Free (2008), Sherwood et al (2008), Haimberger et al (2008)… On the long term trends in ocean heating look at Ishii (2008) or here. – gavin]

  49. 299
    tom watson says:

    Dear Phil, re: 295, Ok you opine I don’t understand, that’s nice. I have a flawed understanding of physical chemistry. But I know, it’s just to complicated to explain. When I was young I never took a Chemistry achievement test. I took the physics one as a junior. I was only in the low 700 range, but I did not take physics until my senior year and although I understood all about currents and magnetic fields and their relationship, there were all these questions using the right hand rule. I did not learn the right hand rule until my senior year. Oh well I had a flawed understanding or what tests really test.

    re Ike Solem 296, Is your post in fact nothing but and attempt to attack my personal ethics and motives. Mr Gavin edited out my comments of a personal nature.

    Now as to my best attempt for honest science, I argue or present what I think is the strongest scientific to the heart of the matter issue. As to my being an agent of PR, well I never thought of you as an agent of marketing buzz for carbon credits. I make no judgments of whose life is based on funding for research on catastrophe and thus have an interest in crisis, in ignorance and fear uncertainty and doubt.

  50. 300
    Ray Ladbury says:

    Tom Watson, you claim to have some background in physics. OK. Great. Learn some. I don’t understand why you insist on pontificating on a subject you clearly don’t understand on a website dedicated to experts providing understanding of that very subject. Doesn’t that strike you as a wee bit odd…or a wee bit trollish?