Dr. Richard Lindzen writes to me with news of this significant new paper saying “It has taken almost 2 years to get this out. “. Part of that problem appears to be hostile reviewers in earlier submissions to JGR, something we’ve seen recently with other skeptical papers, such as O’Donnell’s rebuttal to Steig et al (Antarctica is warming) where Steig himself inappropriately served as a reviewer, and a hostile one at that.
Hostile reviewers aside, the paper will now be published in an upcoming issue of the Asia-Pacific Journal of Atmospheric Sciences and I am honored to be able to be able to present it here. The authors state that:
“We have corrected the approach of Lindzen and Choi (2009), based on all the criticisms made of the earlier work (Chung et al., 2010; Murphy, 2010; Trenberth et al., 2010).”
…
The present paper responds to the criticism, and corrects the earlier approach where appropriate. The earlier results are not significantly altered, and we show why these results differ from what others like Trenberth et al. (2010), and Dessler (2010) obtain.
So, while that may satisfy some critics, given the hostility shown to the idea that there is a low sensitivity to forcings, I’m sure a whole new crop of critics will spring up for this paper. The response to this paper in AGW proponent circles, like the feedback posited for Earth’s climate system, will surely be negative. Let the games begin.
Some highlights:
However, warming from a doubling of CO2 would only be about 1°C (based on simple calculations where the radiation altitude and the Planck temperature depend on wavelength in accordance with the attenuation coefficients of wellmixed CO2 molecules; a doubling of any concentration in ppmv produces the same warming because of the logarithmic dependence of CO2’s absorption on the amount of CO2) (IPCC, 2007).
…
This modest warming is much less than current climate models suggest for a doubling of CO2. Models predict warming of from 1.5°C to 5°C and even more for a doubling of CO2
…
As a result, the climate sensitivity for a doubling of CO2 is estimated to be 0.7 K (with the confidence interval 0.5K – 1.3 K at 99% levels). This observational result shows that model sensitivities indicated by the IPCC AR4 are likely greater than than the possibilities estimated from the observations.
…
Our analysis of the data only demands relative instrumental stability over short periods, and is largely independent of long term drift.
Willis Eschenbach will no doubt find some interesting things in this paper, as it speaks of some of the same regulation mechanisms in the tropics as Willis has opined on here at WUWT. Here’s the Abstract and Conclusion, a link to the full paper follows:
==============================================================
On the Observational Determination of Climate Sensitivity and Its Implications
Richard S. Lindzen1 and Yong-Sang Choi2
1Program in Atmospheres, Oceans, and Climate, Massachusetts Institute of Technology, Cambridge, U. S. A.
2Department of Environmental Science and Engineering, Ewha Womans University, Seoul, Korea
Asia-Pacific J. Atmos. Sci., 47(4), 377-390, 2011 DOI:10.1007/s13143-011-0023-x
Abstract:
We estimate climate sensitivity from observations, using the deseasonalized fluctuations in sea surface temperatures (SSTs) and the concurrent fluctuations in the top-of-atmosphere (TOA) outgoing radiation from the ERBE (1985-1999) and CERES (2000-2008) satellite instruments. Distinct periods of warming and cooling in the SSTs were used to evaluate feedbacks. An earlier study (Lindzen and Choi, 2009) was subject to significant criticisms. The present paper is an expansion of the earlier paper where the various criticisms are taken into account. The present analysis accounts for the 72 day precession period for the ERBE satellite in a more appropriate manner than in the earlier paper. We develop a method to distinguish noise in the outgoing radiation as well as radiation changes that are forcing SST changes from those radiation changes that constitute feedbacks to changes in SST. We demonstrate that our new method does moderately well in distinguishing positive from negative feedbacks and in quantifying negative feedbacks. In contrast, we show that simple regression methods used by several existing papers generally exaggerate positive feedbacks and even show positive feedbacks when actual feedbacks are negative. We argue that feedbacks are largely concentrated in the tropics, and the tropical feedbacks can be adjusted to account for their impact on the globe as a whole. Indeed, we show that including all CERES data (not just from the tropics) leads to results similar to what are obtained for the tropics alone – though with more noise. We again find that the outgoing radiation resulting from SST fluctuations exceeds the zerofeedback response thus implying negative feedback. In contrast to
this, the calculated TOA outgoing radiation fluxes from 11 atmospheric models forced by the observed SST are less than the zerofeedback response, consistent with the positive feedbacks that characterize these models. The results imply that the models are
exaggerating climate sensitivity.
Conclusion:
We have corrected the approach of Lindzen and Choi (2009), based on all the criticisms made of the earlier work (Chung et al., 2010; Murphy, 2010; Trenberth et al., 2010). First of all, to improve the statistical significance of the results, we supplemented ERBE data with CERES data, filtered out data noise with 3-month smoothing, objectively chose the intervals based on the smoothed data, and provided confidence intervals for all sensitivity estimates. These constraints helped us to more accurately obtain climate feedback factors than with the original use of monthly data. Next, our new formulas for climate feedback
and sensitivity reflect sharing of tropical feedback with the globe, so that the tropical region is now properly identified as an open system. Last, the feedback factors inferred from the atmospheric models are more consistent with IPCC-defined climate sensitivity
than those from the coupled models. This is because, in the presence of cloud-induced radiative changes altering SST, the climate feedback estimates by the present approach tends to be inaccurate. With all corrections, the conclusion still appears to be
that all current models seem to exaggerate climate sensitivity (some greatly). Moreover, we have shown why studies using simple regressions of ΔFlux on ΔSST serve poorly to determine feedbacks.
To respond to the criticism of our emphasis on the tropical domain (Murphy, 2010; Trenberth et al., 2010), we analyzed the complete record of CERES for the globe (Dessler, 2010) (Note that ERBE data is not available for the high latitudes since the field-of-view is between 60oS and 60oN). As seen in the previous section, the use of the global CERES record leads to a result that is basically similar to that from the tropical data in this
study. The global CERES record, however, contains more noise than the tropical record.
This result lends support to the argument that the water vapor feedback is primarily restricted to the tropics, and there are reasons to suppose that this is also the case for cloud feedbacks. Although, in principle, climate feedbacks may arise from any
latitude, there are substantive reasons for supposing that they are, indeed, concentrated mostly in the tropics. The most prominent model feedback is that due to water vapor, where it is commonly noted that models behave roughly as though relative humidity
were fixed. Pierrehumbert (2009) examined outgoing radiation as a function of surface temperature theoretically for atmospheres with constant relative humidity. His results are shown in Fig. 13.
Specific humidity is low in the extratropics, while it is high in the tropics. We see that for extratropical conditions, outgoing radiation closely approximates the Planck black body radiation (leading to small feedback). However, for tropical conditions, increases in outgoing radiation are suppressed, implying substantial positive feedback. There are also reasons to suppose that cloud feedbacks are largely confined to the tropics. In the
extratropics, clouds are mostly stratiform clouds that are associated with ascending air while descending regions are cloudfree. Ascent and descent are largely determined by the large scale wave motions that dominate the meteorology of the extratropics, and for these waves, we expect approximately 50% cloud cover regardless of temperature (though details may depend on temperature). On the other hand, in the tropics, upper level clouds, at least, are mostly determined by detrainment from cumulonimbus towers, and cloud coverage is observed to depend significantly on temperature (Rondanelli and Lindzen, 2008).
As noted by LCH01, with feedbacks restricted to the tropics, their contribution to global sensitivity results from sharing the feedback fluxes with the extratropics. This led to inclusion of the sharing factor c in Eq. (6). The choice of a larger factor c leads to
a smaller contribution of tropical feedback to global sensitivity, but the effect on the climate sensitivity estimated from the observation is minor. For example, with c = 3, climate sensitivity from the observation and the models is 0.8 K and a higher value
(between 1.3 K and 6.4 K), respectively. With c = 1.5, global equilibrium sensitivity from the observation and the models is 0.6 K and any value higher than 1.6 K, respectively. Note that, as in LCH01, we are not discounting the possibility of feedbacks in the extratropics, but rather we are focusing on the tropical contribution to global feedbacks. Note that, when the dynamical heat transports toward the extratropics are taken into account, the overestimation of tropical feedback by GCMs may lead to even greater overestimation of climate sensitivity (Bates, 2011).
This emphasizes the importance of the tropical domain itself. Our analysis of the data only demands relative instrumental stability over short periods, and is largely independent of long term drift. Concerning the different sampling from the ERBE and CERES instruments, Murphy et al. (2009) repeated the Forster and Gregory (2006) analysis for the CERES and found very different values than those from the ERBE. However, in this
study, the addition of CERES data to the ERBE data does little to change the results for ΔFlux/ΔSST – except that its value is raised a little (as is also true when only CERES data is used.). This may be because these previous simple regression approaches include
the distortion of feedback processes by equilibration. In distinguishing a precise feedback from the data, the simple regression method is dependent on the data period, while our method is not. The simple regression result in Fig. 7 is worse if the model
integration time is longer (probably due to the greater impact of increasing radiative forcing).
Our study also suggests that, in current coupled atmosphereocean models, the atmosphere and ocean are too weakly coupled since thermal coupling is inversely proportional to sensitivity (Lindzen and Giannitsis, 1998). It has been noted by Newman et al. (2009) that coupling is crucial to the simulation of phenomena like El Niño. Thus, corrections of the sensitivity of current climate models might well improve the behavior of coupled
models, and should be encouraged. It should be noted that there have been independent tests that also suggest sensitivities less than predicted by current models. These tests are based on the response to sequences of volcanic eruptions (Lindzen and Giannitsis, 1998), on the vertical structure of observed versus modeled temperature increase (Douglass, 2007; Lindzen, 2007), on ocean heating (Schwartz, 2007; Schwartz, 2008), and on
satellite observations (Spencer and Braswell, 2010). Most claims of greater sensitivity are based on the models that we have just shown can be highly misleading on this matter. There have also been attempts to infer sensitivity from paleoclimate data (Hansen
et al., 1993), but these are not really tests since the forcing is essentially unknown given major uncertainties in clouds, dust loading and other factors. Finally, we have shown that the attempts to obtain feedbacks from simple regressions of satellite measured outgoing radiation on SST are inappropriate.
One final point needs to be made. Low sensitivity of global mean temperature anomaly to global scale forcing does not imply that major climate change cannot occur. The earth has, of course, experienced major cool periods such as those associated with ice ages and warm periods such as the Eocene (Crowley and North, 1991). As noted, however, in Lindzen (1993), these episodes were primarily associated with changes in the equatorto-
pole temperature difference and spatially heterogeneous forcing. Changes in global mean temperature were simply the residue of such changes and not the cause.
==============================================================
Dr. Lindzen has the full paper on his personal website here:
http://www-eaps.mit.edu/faculty/lindzen/236-Lindzen-Choi-2011.pdf
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Bernie McCune says:
August 17, 2011 at 6:44 am
————————-
A very heartening comment Bernie. Thank you. I have mentioned many times, as a non-scientist, that I have noticed, in my global travels, that tropical daytime clear air temperatures are usually less than desert daytime temperatures and thus humidity, water vapour, H20 molecules, are a solar SHIELD in the daytime rather than a “greenhouse gas” at nightime. Simply compare the radiative energy levels at the specified response wavelengths for H2O between day and night.
You mention a piece of equipment, a normal incident pyrheliometer (NIP), this sound like a handy gadget to have. Any links on design operation and usage methods? Many thanks.
“steven mosher says:
August 17, 2011 at 9:53 am
first you have to understand that Lindzen is actually estimating the TCR or transient climate response. That’s probably the bit that everyone here missed.”
Agreed. From farther up in the thread:
“Gary Swift says:
August 17, 2011 at 6:41 am
How did this paper address the possibility that time to equilibrium is longer? I seems that a long equilibrium time might still allow high sensitivity on longer time scales. Any thoughts?”
To be fair, there are some signs that the equilibrium lapse rate isn’t as long as a hundred years. If 80% of the efffect happens almost instantly, then the other 20% takes 500 years, then Lindzen could have a point. I think it’s clear that it’s at least a two stage process, with some portion happening quickly and some other portion happening on a longer time scale, but that ratio is debatable as well as the time scale for each part. It’s certainly broken into a lot more than two parts though. Uhhhgg. That makes my head hurt just thinking about it.
steven mosher says:
August 17, 2011 at 9:53 am
The ECR or equillibrium climate response is what happens over longer periods of time and includes those processes that take longer to develop, like changes in albedo. The ECR takes hundreds of years. When people talk about sensitivity they are talking about the ECR.
The observation record is too short to a good estimate of the ECR. You get a nice lower bound however.
To estimate the ECR you have two choices: paleo and modelling. So hansen looks at the million year response and estimates the sensitivity as 3C.
———————————————————————————————————————————–
So time scales on the order of hundreds of years are needed for observations to confirm the AGW theory. Hmm. Good for grants in the short term. In the absence of measurement, we are stuck with using erroneous models and ‘measuring’ something from the ‘before time’ using proxies or other models/estimates.
Stephen Mosher said “He’s comparing the TCR from observations to the ECRs of climate models.
two entirely different beasts.”
So, to be clear, are you saying the paper is fundamentally flawed?
Ja, Ja.
The problem I have with this paper is that it starts with:
It is generally accepted that in the absence of feedback, a doubling of CO2 will cause a forcing of deltaQ= 3.7 W/m2…..
On this everyhting hangs….
But how was this determined?
How much radiative cooling (mostly by re-radiating near IR and IR radiation) and how much radiative warming is caused by the CO2? How were those experiments done?
and where is are the test results?
http://www.letterdash.com/HenryP/the-greenhouse-effect-and-the-principle-of-re-radiation-11-Aug-2011
mondo says:
August 17, 2011 at 9:56 am
It would be very helpful if some diligent person could provide a listing of all the relevant sceptical peer reviewed papers that have been published and not refuted that demonstrate that the IPCC’s estimate of CO2 sensitivity is too high.
——–
Here is a full list of such papers:
Now, whether the refutations are valid is another question.
Here we see more confusion from Dr. Lindzen. One big question I’ve not seen him address. If the feedback is negative, that feedback would also work to minimize any cooling due to natural causes. So, Dr. Lindzen, tell us how it was possible for the Ice Ages to begin after the last Interglacial and how was it possible that all those glaciers which buried Eastern Canada and parts of the US as far south as NYC and Boston melted later? Inquiring minds want to know.
@Mosher
“Imagine you slam your pedal to the floor. Then you take a short snap shot of your acceleration
at the begining of your run or anywhere in the run. How well can you estimate the Total system response to that forcing. That is, how well can you estimate your final velocity? err not too well”
Actually, that’s completely incorrect. If you know the right variables (current speed, current acceleration, frictional forces), you can easily take any snap shot of acceleration and compute the final velocity: that’s basic physics 101. In fact, I DID that in my physics 101.
The same is true of climate. If you know the TCR, and you know how that interplays with the other variables, you can compute the final temperature (velocity) at any time point, and for any changes in those other variables that may or may not occur.
So actually, I have to completely disagree with you. If we know how climate works well enough, all we need to know is the TCR to know the ECR.
Steve Mosher says “Lindzen is actually estimating the TCR or transient climate response. ”
This is an important observation. We should also remember that what he extracted from the model responses was the TCR over the same timeframe.
To the extent that the models have the correct TCR to ECR ratio, then the excessive TCR noted by Linzen will also be reflected as too high of equilibrium climate response in the model.
Hansen’s 2011 whitepaper, Earth’s Energy Imbalance and Implications, has an interesting and very readable section on the climate response function vs. time.
I don’t fully understand the implications of Lindzen’s methodology, but at first glance it appears that his result is independent of the length of the time segments used for delta-SST and delta-flux. If my understanding is correct, then he has figured out the transient sensitivity that corresponds to the 10 year or or 100 year breakpoints on Hansen’s figure 9 in “Energy Imbalance and Implications” whitepaper. In that range the climate response is about 50% of the equilibrium response.
In other words, the TCR of 0.7 C per doubling that Lindzen observed corresponds to about 1.4 C per doubling ECR.
steven mosher:
At August 17, 2011 at 9:53 am you say;
“first you have to understand that Lindzen is actually estimating the TCR or transient climate response.”
and
“The ECR or equillibrium climate response is what happens over longer periods of time and includes those processes that take longer to develop, like changes in albedo. The ECR takes hundreds of years. When people talk about sensitivity they are talking about the ECR.”
and
“To estimate the ECR you have two choices: paleo and modelling. So hansen looks at the million year response and estimates the sensitivity as 3C.”
OK. I could quibble with all of that, but here I will accept it as being true.
What “takes hundreds of years” has no relevance to human activity. People adapt – and always have adapted – to such slow changes without noticing they are doing it.
And the “million year response” is totally irrelevant: we will probably have an ice age before then.
At issue is
(a) the climate sensitivity appropriate for inclusion in climate models ‘projecting’ coming decades, and that is clearly the TCM and NOT the ECM
and
(b) whether immediate mitigation options are required: a low TCM indicates they are not.
Furthermore, the actions of Hansen in calling for immediate mitigation options on the basis of “the million year response” is – to say the least – reprehensible.
Richard
I am beginning to think that even Lindzen and friends are wrong. i dont believe C02 has ANY + effect on temperatures because all the extra heat is probably lost anyway refer to Spencer and Braswell. The sun controls the rest it so B***** obvious.
“Ged says:
August 17, 2011 at 10:53 am
So actually, I have to completely disagree with you. If we know how climate works well enough, all we need to know is the TCR to know the ECR”
But we don’t know the equilibrium time. In the car analogy, this would be like not knowing the horsepower and slope of the road. What if your snapshot was taken before the crest of a hill? How good would your physics 101 calculation be if you didn’t know that?
Steve Mosher says “He’s comparing the TCR from observations to the ECRs of climate models.
two entirely different beasts. ”
This statement I disagree with. In section 5 of his paper he used essentially the same method to extract sensitivity from the model runs as he did from the observed SST and flux data.
While the sensitivities calculated this way correspond to neither the ECR nor the IPCC “70 years at 1%/yr CO2 increase” transient sensitivity, the table 4 in Lindzen’s paper lists model sensitivities calculated the same way as he did with the observations. Those model sensitivities are significantly higher than what is observed.
One can argue that what Lindzen observed is not relevant and the fact that the models are overly sensitive when calculated in this manner, but it definitely is not a case of Lindzen comparing TCR to ECR.
One could make the argument that all that Lindzen has shown is that the models do not have enough coupling between the atmosphere and the ocean, but increasing that coupling would decrease both TCR and ECR.
Matt says:
August 17, 2011 at 7:33 am
Thanks, Matt, for some good points. For this one, however … citation? Here’s one for a start … obviously they relate to sensitivity at varying timescales.
Regards,
w.
DCA says:
August 17, 2011 at 6:23 am
Gavin Schmidt has been saying lately that the paleo data are more important than the recent observations. Now we know why.
How would one respond to his assertion?
—–
CRS reply Well, let’s see…..repeatability would be the first way to go after paleo techniques, as well as sampling error, complications in interpretation (is tree growth reduced due to temperature or moisture, lack of nutrients, solar inputs etc.?).
I consider paleo the weakest of the climate methodologies, so if that is what Gavin is trying to hang his hat on, good luck with that. Steve MacIntyre has written very elegant articles about this:
http://climateaudit.org/2009/09/27/yamal-a-divergence-problem/
In reply to John B:
John B says:
August 17, 2011 at 1:14 am
Ursus Augustus says:
August 16, 2011 at 11:54 pm
I think there is a scientific consensus emerging as evidenced by this paper and a number of others over the past few years. That consensus is that CO2 is nowhere near the bogey it has been made out to be, that AGW is actually quite modest.
—————
So, a “consensus” is OK as long as it is critical of the mainstream consensus?
You appear to be ignore of the current planetary temperature data. The lack of warming finding is consistent with Lindzen and Choi’s paper: On the Observational Determination of Climate Sensitivity and Its Implications.
Observations do not support the IPCC alarmist hypothesis that includes massive positive feedback to amplify the CO2 warming to produce a predicted 3.3C warming for a doubling of CO2. The implication of Lindzen and Choi’s analysis of satellite data is a doubling of CO2 will result in roughly 1C warming with most of the warming at higher latitudes where it will be beneficial to the biosphere. Lindzen and Choi do not need to hide their data or destroy their emails. They are braving practicing science. Analysis the data and present the results.
Public policy must be factual based.
Trillions of dollars are being advocated to be spent on bureaucracies to monitor CO2, for CO2 trading systems, on CO2 sequestration, on biofuel subsidies, on wind farm subsidies, on new power lines to pass power (with roughly 30% losses, long power lines do not make engineering or commercial sense), and so.
The engineering solutions proposed to arrest extreme AWG are boondoggles not solutions. A consequence of the AWG alarmist paradigm is people are not questioning the boondoggles. To ask critical questions is to risk being called a “denier”.
The western governments do not have trillions of dollars of surplus tax revenue. This is a fixed limit to deficit spending.
Willis:
You provide a good citation in your post at August 17, 2011 at 11:35 am but it is the same citation that I linked to above at August 17, 2011 at 7:56 am.
I may be wrong, but I think Matt was asking for additional references.
Richard
@richard 111
Our instrument was made by Eppley Labs. Don’t have the model number but it was their standard NIP. Evacuated barrel mounted on a small clocked equatorial tracker. Align it to the sun in the morning and it tracked the sun all day. They are rugged but still a laboratory instrument so I don’t recall that they were inexpensive (several thousands of $?).
Clouds took the readings to very close to zero. Jet contrails put a sizeable glitch in the reading. We used it to verify that we were getting full power into our solar furnace beam during a test run. But if you paid attention, a number of interesting things happen to the incoming solar levels that made us all look into what was actually going on. Neat!
Bernie
E. Swanson:
At August 17, 2011 at 10:50 am you say;
“Here we see more confusion from Dr. Lindzen.”
No, if there is any “confusion” it is yours. Lindzen & Choi measured climate sensitivity. They said nothing about how or why the Earth came out of the last ice age. But the value they obtained indicates your stated understanding of how or why the Earth came out of the last ice age is wrong.
Your understanding cannot disprove the result obtained by Lindzen & Choi.
The result obtained by Lindzen & Choi disproves your understanding.
So, you need to adjust your understanding unless and until the finding of Lindzen & Choi is shown to be wrong.
This is called science.
Richard
If the deep oceans and the land/ice is only absorbing about 0.35W/m2, we can easily say whether temperatures are increasing the way the theory predicts – in the short-term and in the long-term.
How much warming are we missing if 0.35W/m2 is being temporarily diverted to warming something else other than the atmosphere and the sea surface – a tiny, tiny amount.
As of today and in the last 7 years, we are within months to a year of the equilibrium response.
Richard S Courtney says:
August 17, 2011 at 11:44 am
Thanks, Richard. My bad, you got there first, no surprise. Me, I’m waiting for his references.
w.
steven mosher: This “transient response” thing is getting pretty annoying. As others have noted, Lindzen has calculated the same numbers for the models with the same method. So then the models are showing a “transient response” if this method is to be believed as successfully teasing that out, that is much higher than the “transient response” calculated the same way from observations. Now something is wrong here, right? Because if we are to believe that this finding is not inconsistent with high sensitivity, then the models should also show low sensitivity by this method…except they don’t. And there is a very simple reason for that: the argument that the fluxes of radiation are giving the transient response is just wrong. It is easy to see where you are becoming confused. If one takes a comparison between a forcing and temperature change, instantaneously, you have calculated the transient response. Why? Because the full temperature response to the forcing is not instantaneous, but rather takes time. But you are totally wrong if you think this same situation applies to assessing feedback. Feedback is the response of various radiative components to a temperature change that has occurred, not that “will”. If more temperature change would occur at equilibrium, the feedback responses would scale with that. In other words, it is meaningless to bring up the idea of “transient response” when talking about feedback. It is a problem that applies to the effect of a forcing on temperature. Let’s see if we can’t describe this in detail…
Imagine for the sake of argument a system with known sensitivity of say .3 K /W/m^2. Impose a forcing of 1 W/m^2 on the system, and suppose then it instantaneously warms by .15 K. Your transient response calculated from delta T divided by delta F is .15 K/W/m^2, or half the known equilibrium response. Okay, that’s comparing the forcing with the feedback. However, what about the feedback? Well, for our known sensitivity, we know that this system emits an extra 3.33 Watts per meter squared when it is one degree warmer. So the extra watts that the system feedbacks out when it is .15 degrees warmer is about .5 Watts per meter squared. Funnily enough if you divide .15 by .5 you get .3 K/W/m^2, in other words, you extract the correct sensitivity from the transient temperature change when assessing from feedback.
So the “transient response” comment is totally irrelevant to the way Lindzen is actually calculating sensitivity. You can see this is clearly true because otherwise the climate models would have uniformly had underestimated sensitivity. Lindzen’s method didn’t do that with the models.
“We estimate climate sensitivity from observations …”
Say WHAT?!? You can’t base science on what you SEE, you MORON!!! It has to be strictly THEORETICAL!!!!!! How do you expect to get funding if you let FACTS get in the way???
/sarc
steven mosher says:
August 17, 2011 at 9:53 am
The work of myself and others (here and here) have shown that the models are functionally equivalent to a linear response to the forcing with a short (a few years) time constant. So contrary to your claim, the models can tell us nothing about a hundred year response. They are fully equivalent to and give identical results to those calculated by a linear forcing response plus a short time lag.
w.
BTW, Mosher, paleo will only give correct sensitivity if one knows the correct forcing that caused a temperature change. If you don’t know the forcing, the sensitivity you get is wrong. This is part of what is wrong with Hansen and other’s such attempts. The other problem is assessing changes associated with larger changes in the equator to pole temperature difference as being due to a globally averaged top of the atmosphere radiative forcing, despite the fact that the mechanism for the glaciations was changes in the latitudinal distribution of insolation. Hansen’s LGM estimate includes no Milankovitch forcing (because globally it averages out) so he complete ignores the known factor for initiating the the glaciations/interglacials in favor of attributing them to global forcings that at best amount to feedbacks. It speaks to a failed paradigm. The actually sensitivity implied by his data, if one takes ice sheets/vegetation and greenhouse gases as changes that occurred in response to the glaciation (feedback), then only “Dust” is left to cause the glaciation, and the implied sensitivity is 30 C for a doubling of CO2. Clearly wrong: the first reason, because there are important forcings that Hansen’s estimate excludes (some of which are probably not even known) and secondly because the actual mechanism does not fit into the paradigm that he is trying to explain the glaciations with.