NOTE: This post is important, so I’m going to sticky it at the top for quite a while. I’ve created a page for all Spencer and Braswell/Dessler related posts, since they are becoming numerous and popular to free up the top post sections of WUWT.
UPDATE: Dr. Spencer writes: I have been contacted by Andy Dessler, who is now examining my calculations, and we are working to resolve a remaining difference there. Also, apparently his paper has not been officially published, and so he says he will change the galley proofs as a result of my blog post; here is his message:
“I’m happy to change the introductory paragraph of my paper when I get the galley proofs to better represent your views. My apologies for any misunderstanding. Also, I’ll be changing the sentence “over the decades or centuries relevant for long-term climate change, on the other hand, clouds can indeed cause significant warming” to make it clear that I’m talking about cloud feedbacks doing the action here, not cloud forcing.”
[Dessler may need to make other changes, it appears Steve McIntyre has found some flaws related to how the CERES data was combined: http://climateaudit.org/2011/09/08/more-on-dessler-2010/
As I said before in my first post on Dessler’s paper, it remains to be seen if “haste makes waste”. It appears it does. -Anthony]
Update #2 (Sept. 8, 2011): Spencer adds: I have made several updates as a result of correspondence with Dessler, which will appear underlined, below. I will leave it to the reader to decide whether it was our Remote Sensing paper that should not have passed peer review (as Trenberth has alleged), or Dessler’s paper meant to refute our paper.
by Roy W. Spencer, Ph. D.
While we have had only one day to examine Andy Dessler’s new paper in GRL, I do have some initial reaction and calculations to share. At this point, it looks quite likely we will be responding to it with our own journal submission… although I doubt we will get the fast-track, red carpet treatment he got.
There are a few positive things in this new paper which make me feel like we are at least beginning to talk the same language in this debate (part of The Good). But, I believe I can already demonstrate some of The Bad, for example, showing Dessler is off by about a factor of 10 in one of his central calculations.
Finally, Dessler must be called out on The Ugly things he put in the paper.
(which he has now agreed to change).
1. THE GOOD
Estimating the Errors in Climate Feedback Diagnosis from Satellite Data
We are pleased that Dessler now accepts that there is at least the *potential* of a problem in diagnosing radiative feedbacks in the climate system *if* non-feedback cloud variations were to cause temperature variations. It looks like he understands the simple-forcing-feedback equation we used to address the issue (some quibbles over the equation terms aside), as well as the ratio we introduced to estimate the level of contamination of feedback estimates. This is indeed progress.
He adds a new way to estimate that ratio, and gets a number which — if accurate — would indeed suggest little contamination of feedback estimates from satellite data. This is very useful, because we can now talk about numbers and how good various estimates are, rather than responding to hand waving arguments over whether “clouds cause El Nino” or other red herrings. I have what I believe to be good evidence that his calculation, though, is off by a factor of 10 or so. More on that under THE BAD, below.
Comparisons of Satellite Measurements to Climate Models
Figure 2 in his paper, we believe, helps make our point for us: there is a substantial difference between the satellite measurements and the climate models. He tries to minimize the discrepancy by putting 2-sigma error bounds on the plots and claiming the satellite data are not necessarily inconsistent with the models.
But this is NOT the same as saying the satellite data SUPPORT the models. After all, the IPCC’s best estimate projections of future warming from a doubling of CO2 (3 deg. C) is almost exactly the average of all of the models sensitivities! So, when the satellite observations do depart substantially from the average behavior of the models, this raises an obvious red flag.
Massive changes in the global economy based upon energy policy are not going to happen, if the best the modelers can do is claim that our observations of the climate system are not necessarily inconsistent with the models.
(BTW, a plot of all of the models, which so many people have been clamoring for, will be provided in The Ugly, below.)
2. THE BAD
The Energy Budget Estimate of How Much Clouds Cause Temperature Change
While I believe he gets a “bad” number, this is the most interesting and most useful part of Dessler’s paper. He basically uses the terms in the forcing-feedback equation we use (which is based upon basic energy budget considerations) to claim that the energy required to cause changes in the global-average ocean mixed layer temperature are far too large to be caused by variations in the radiative input into the ocean brought about by cloud variations (my wording).
He gets a ratio of about 20:1 for non-radiatively forced (i.e. non-cloud) temperature changes versus radiatively (mostly cloud) forced variations. If that 20:1 number is indeed good, then we would have to agree this is strong evidence against our view that a significant part of temperature variations are radiatively forced. (It looks like Andy will be revising this downward, although it’s not clear by how much because his paper is ambiguous about how he computed and then combined the radiative terms in the equation, below.)
But the numbers he uses to do this, however, are quite suspect. Dessler uses NONE of the 3 most direct estimates that most researchers would use for the various terms. (A clarification on this appears below) Why? I know we won’t be so crass as to claim in our next peer-reviewed publication (as he did in his, see The Ugly, below) that he picked certain datasets because they best supported his hypothesis.
The following graphic shows the relevant equation, and the numbers he should have used since they are the best and most direct observational estimates we have of the pertinent quantities. I invite the more technically inclined to examine this. For those geeks with calculators following along at home, you can run the numbers yourself:
Here I went ahead and used Dessler’s assumed 100 meter depth for the ocean mixed layer, rather than the 25 meter depth we used in our last paper. (It now appears that Dessler will be using a 700 m depth, a number which was not mentioned in his preprint. I invite you to read his preprint and decide whether he is now changing from 100 m to 700 m as a result of issues I have raised here. It really is not obvious from his paper what he used).
Using the above equation, if I assumed a feedback parameter λ=3 Watts per sq. meter per degree, that 20:1 ratio Dessler gets becomes 2.2:1. If I use a feedback parameter of λ=6, then the ratio becomes 1.7:1. This is basically an order of magnitude difference from his calculation.
Again I ask: why did Dessler choose to NOT use the 3 most obvious and best sources of data to evaluate the terms in the above equation?:
(1) Levitus for observed changes in the ocean mixed layer temperature; (it now appears he will be using a number consistent with the Levitus 0-700 m layer).
(2) CERES Net radiative flux for the total of the 2 radiative terms in the above equation, and (this looks like it could be a minor source of difference, except it appears he put all of his Rcld variability in the radiative forcing term, which he claims helps our position, but running the numbers will reveal the opposite is true since his Rcld actually contains both forcing and feedback components which partially offset each other.)
(3): HadSST for sea surface temperature variations. (this will likely be the smallest source of difference)
The Use of AMIP Models to Claim our Lag Correlations Were Spurious
I will admit, this was pretty clever…but at this early stage I believe it is a red herring.
Dessler’s Fig. 1 shows lag correlation coefficients that, I admit, do look kind of like the ones we got from satellite (and CMIP climate model) data. The claim is that since the AMIP model runs do not allow clouds to cause surface temperature changes, this means the lag correlation structures we published are not evidence of clouds causing temperature change.
Following are the first two objections which immediately come to my mind:
1) Imagine (I’m again talking mostly to you geeks out there) a time series of temperature represented by a sine wave, and then a lagged feedback response represented by another sine wave. If you then calculate regression coefficients between those 2 time series at different time leads and lags (try this in Excel if you want), you will indeed get a lag correlation structure we see in the satellite data.
But look at what Dessler has done: he has used models which DO NOT ALLOW cloud changes to affect temperature, in order to support his case that cloud changes do not affect temperature! While I will have to think about this some more, it smacks of circular reasoning. He could have more easily demonstrated it with my 2 sine waves example.
Assuming there is causation in only one direction to produce evidence there is causation in only one direction seems, at best, a little weak.
2) In the process, though, what does his Fig. 1 show that is significant to feedback diagnosis, if we accept that all of the radiative variations are, as Dessler claims, feedback-induced? Exactly what the new paper by Lindzen and Choi (2011) explores: that there is some evidence of a lagged response of radiative feedback to a temperature change.
And, if this is the case, then why isn’t Dr. Dessler doing his regression-based estimates of feedback at the time lag or maximum response? Steve McIntyre, who I have provided the data to for him to explore, is also examining this as one of several statistical issues. So, Dessler’s Fig. 1 actually raises a critical issue in feedback diagnosis he has yet to address.
3. THE UGLY
(MOST, IF NOT ALL, OF THESE OBJECTIONS WILL BE ADDRESSED IN DESSLER’S UPDATE OF HIS PAPER BEFORE PUBLICATION)
The new paper contains a few statements which the reviewers should not have allowed to be published because they either completely misrepresent our position, or accuse us of cherry picking (which is easy to disprove).
Misrepresentation of Our Position
Quoting Dessler’s paper, from the Introduction:
“Introduction
The usual way to think about clouds in the climate system is that they are a feedback… …In recent papers, Lindzen and Choi [2011] and Spencer and Braswell [2011] have argued that reality is reversed: clouds are the cause of, and not a feedback on, changes in surface temperature. If this claim is correct, then significant revisions to climate science may be required.”
But we have never claimed anything like “clouds are the cause of, and not a feedback on, changes in surface temperature”! We claim causation works in BOTH directions, not just one direction (feedback) as he claims. Dr. Dessler knows this very well, and I would like to know
1) what he was trying to accomplish by such a blatant misrepresentation of our position, and
2) how did all of the peer reviewers of the paper, who (if they are competent) should be familiar with our work, allow such a statement to stand?
Cherry picking of the Climate Models We Used for Comparison
This claim has been floating around the blogosphere ever since our paper was published. To quote Dessler:
“SB11 analyzed 14 models, but they plotted only six models and the particular observational data set that provided maximum support for their hypothesis. “
How is picking the 3 most sensitive models AND the 3 least sensitive models going to “provide maximum support for (our) hypothesis”? If I had picked ONLY the 3 most sensitive, or ONLY the 3 least sensitive, that might be cherry picking…depending upon what was being demonstrated. And where is the evidence those 6 models produce the best support for our hypothesis?
I would have had to run hundreds of combinations of the 14 models to accomplish that. Is that what Dr. Dessler is accusing us of?
Instead, the point was to show that the full range of climate sensitivities represented by the least and most sensitive of the 14 models show average behavior that is inconsistent with the observations. Remember, the IPCC’s best estimate of 3 deg. C warming is almost exactly the warming produced by averaging the full range of its models’ sensitivities together. The satellite data depart substantially from that. I think inspection of Dessler’s Fig. 2 supports my point.
But, since so many people are wondering about the 8 models I left out, here are all 14 of the models’ separate results, in their full, individual glory:
I STILL claim there is a large discrepancy between the satellite observations and the behavior of the models.
CONCLUSION
These are my comments and views after having only 1 day since we received the new paper. It will take weeks, at a minimum, to further explore all of the issues raised by Dessler (2011).
Based upon the evidence above, I would say we are indeed going to respond with a journal submission to answer Dessler’s claims. I hope that GRL will offer us as rapid a turnaround as Dessler got in the peer review process. Feel free to take bets on that. 
And, to end on a little lighter note, we were quite surprised to see this statement in Dessler’s paper in the Conclusions (italics are mine):
“These calculations show that clouds did not cause significant climate change over the last decade (over the decades or centuries relevant for long-term climate change, on the other hand, clouds can indeed cause significant warming).”
Long term climate change can be caused by clouds??! Well, maybe Andy is finally seeing the light! 
(Nope. It turns out he meant ” *RADIATIVE FEEDBACK DUE TO* clouds can indeed cause significant warming”. An obvious, minor typo. My bad.)
My internet crashed while I was mid-post, so hopefully I am not double posting here. Sorry if I am.
richard verney says in response to R. Gates:
September 11, 2011 at 2:58 am
“Presently, we do not have sufficiently accurate data, nor knowledge and understanding of the system and how each factor interplays and works to be able to construct a useful and reliable model. Period.”
I think this would be the perfect occasion for me to yet again break out my favorite quote from the omnipresent Travesty Kev:
“How come you do not agree with a statement that says we are no where close to knowing where energy is going or whether clouds are changing to make the planet brighter. We are not close to balancing the energy budget. The fact that we can not account for what is happening in the climate system makes any consideration of geoengineering quite hopeless as we will never be able to tell if it is successful or not! It is a travesty!”
Beautiful, isn’t it? His having saturated every nook of this debate leads me to invent a new and improved game: Three Degrees of Kevin Trenberth which proposes that any laughable AGW development can be linked back to T-Kev in three steps or less.
Maybe that’s a bit ambitious and it should instead be Four Degrees, but either way it is a robust improvement over the previous model. I do admit though that the original Six Degrees does offer the adianoetic reference to the upper bounds of IPCC projections. Hmm. Anyway, feel free to give it a shot. The S&B/Dessler story is a one degree example from several angles of course.
Tim Spence says:
September 11, 2011 at 7:53 am
http://www.geocraft.com/WVFossils/greenhouse_data.html
Dave Springer says:
September 11, 2011 at 5:20 am
“We get an ice planet WITH CO2 you dolt and you don’t need to run a model. You just need a fifth grader’s knowledge of the most recent ice age. Duh.”
____
Appears you are confusing an ice planet (aka snowball earth) with an ice age (which we are in) with a glacial (which we may or may not enter into again). Do some reading, and then we’ll talk.
But you can trust the basic physics on this one…remove all the CO2 from the atmosphere and the ocean surfaces freeze up from pole to equator, all the water moisture will be condensed from the atmosphere.
But you asked this question:
“So what I want to know is not whether there’s too much CO2 in the atmosphere but rather whether there’s enough CO2 in the atmosphere.”
Yes, this idea of us slipping back into a glacial period seems to be common fear of AGW skeptics. I think the RANGE of CO2 being between about 180 ppm and 280ppm has served the development of human civilization quite well over many tens of thousands of years. I don’t think you need to worry about any approaching glacial period with CO2 now nearing 400 ppm. Quite the opposite, we’ll find out if our food grains, and ocean food chain hold up enough in a much warmer world to support 7 billion people and rising.
Richard Verney:
You act as though global climate models were mere toys, based on some random set of assumptions…and I can understand how a skeptic might want to believe this, but it is flatly wrong. But before continuing, let me use this quote that I lifted from a new paper put out by Judith Curry. The quote is:
“All models are wrong, but some are useful.” George E.P. Box
Her full paper is here: http://journals.ametsoc.org/doi/pdf/10.1175/2011BAMS3139.1
So, we can fully acknowledge that models are wrong, and everyone who uses and develops them understands that going into it. Models are like maps. They are not the actual territory you are traveling, but they can be useful to find out about that territory. A map (i.e. model) is useful for what it can tell you that is accurate about a territory. Will it show you every stone and tree? Probably not. But the best maps (models) will show the major features. Current climate models are like that. They can show us the major features (i.e. dynamics) and trends of the climate. But, as has been pointed out, the climate is a non-linear dynamical system, and no model is ever going to be able to tell you exactly how such a system will be evolving at the edge of
chaos. The best we can do is to learn as the system changes and continually refine the models as more and more is learned. To abandon the models and wait 10 or 20 years, would be pointless (if the goal is actually advance the science and refine the models), as we would still have to pick up right where we left off, and we’d simply be 10 or 20 years behind.
Richard S Courtney says:
September 11, 2011 at 12:43 am
R. Gates:
At September 10, 2011 at 6:35 am you say to Richard Verney:
“As the climate is a system existing on the edge of chaos, it is taken as a given that no model will be able to predict those inherently unpredictable tipping points exactly.”
Please state the nature of each such ‘tipping point’ that could/may/will be triggered by AGM.
I do not know of any such ‘tipping points’, and the models do NOT predict any such ‘tipping points’ “exactly” or otherwise.
Richard
_____
First of all, It is impossible to predict tipping points in a non-linear dynamical system on the edge of chaos. We only can look into the paleoclimate record and see what has happened in the past when conditions were similar. But let me give you an example of one such tipping point, that could occur, and might (note I said “might”) be occurring right now related to us having the highest CO2 levels since perhaps the mid-Pliocene. There is in fact an international group of scientists studying this issue intensely right now. That has to do with the general warming of the Arctic and melting of permafrost and release of both additional CO2 and methane from both land and under the oceans as the region warms. We don’t know exactly where the “tipping point’ might be, but there is some average land and ocean temperatures at which larger and larger amounts of methane and CO2 will be released from both land and sea floor in and around the Arctic. This will of course lead to additional warming, leading the release of more methane and CO2, and so forth. This is no different that what the general Milankovitch forcing does at it forces more CO2 from the oceans at the beginning of an interglacial to start a positive-feedback warming process, only it would be much greater. So this Arctic warming/permafrost/methane clathrate feedback could easily represent a tipping point.
Now, if such a tipping point did occur, it would dramatically alter the trajectory of our current warming, and looking back into the paleoclimate record, we’d be looking at temperatures more like the Miocene.
But the point is, no model can predict this tipping point…ever, and the best guide we have is looking at the Earth’s past when similar atmospheric composition was seen.
David A says:
September 10, 2011 at 9:11 pm
George E. Smith says:
September 10, 2011 at 7:33 pm
“”””” David A says:
Thanks George, I agree with your comments. My comment to Gates was only the last paragraph hoping he would see some very simple concepts,
“Gates, only two things can affect the energy content of a system in radiative balance, either a change in the input, or a change in the residence time of the energy in the system. Got it? So a question for you. Does the eneregy entering the oceans have a longer residence time then the energy in the atmospher? I hope you say the energy in the oceans. Does it not then follow that a change in the SWR entering the oceans can have a greater affect on the energy balance of the earth then a like change of LWIR in the atmosphere? Think hard on this one, and I await your answer.”
_____
Of course the energy entering the ocean has a longer residence time. But of course, SWR needs to be able to get into the ocean, and in the case of an ice-house planet, (devoid of CO2 and other noncondensing greenhouse gases in the atmosphere) the SWR would not be able to get into the oceans, as they would be covered by a thick layer of ice and snow and the Earth’s albedo would be quite high. Related to our current circumstances, the majority of the warming going on so far (by far the majority) is in the oceans, judging by such metrics as ocean heat content. Far more extra joules of energy have gone into the oceans. But this is a bit of a mystery to skeptics is it not? We have NOT had the commensurate increase in SW radiation during the period of time we’ve seen the ocean heat content go up (i.e. the last 30 years or so?). So where is this extra heat coming from? The answer of course is that less energy has been leaving the system due to additional greenhouse gas concentrations (CO2, methane, and NO2) and so the extra heat is being stored in the very large buffer of the ocean.
But a larger point needs to be made about energy balances, and not just “heat” or temperature. When looking at the atmosphere or oceans, we really should be looking at the total energy balance, and not just heat. A recent paper about this very issue is here:
http://www.agu.org/pubs/crossref/2011/2011GL048442.shtml
We’d perhaps hope to see a metric developed over the next few years that could actually measure total energy content of both ocean and atmosphere, taking into consideration enthalpy, latent heat, sensible heat, currents, winds, etc.
Richard Verney:
“You act as though global climate models were mere toys, based on some random set of assumptions…and I can understand how a skeptic might want to believe this, ”
Would you accept that the models are trying to mimic a chaotic system? Would you climb into a space rocket based on computer simulated models that did not have proven engineering theories? (Yep, way back some guys did but they were so lucky!) Why should we be paying out billions in taxes for unproved theories and models that have failed, for getting on ten years! and do not go there with the “what if” scenarios!
In Mann’s H.S. case the tree proxies are truly garbage, His use of statistics is childish to say the least, though the word fraudulent would be a better description when it come to the use of the made up RE rather than R2!
Currently the models really are no better than toys (the tracking of the last hurricane proved that) and the blogs are more accurate with the Nina predictions and for that my son gives thanks and polishes (for the second year) his snow board over in San Fran!
Instead of moaning, simply explain for me and a host of others, the simple and the proven theory of CO2 in relation to AGW. Also explain where the “Hotspot” is. That should keep you busy for a while and I look forward to your convincing evidence.
I find some of the comments here beyond strange.
Since when did H2O need CO2 to absorb infrared?
I do wish people would provide links for these amazing claims.
Tim Spence says:
September 11, 2011 at 7:53 am
… I’m also trying to find out which gases are reducing in response to increased C02.
————
During the combustion of Carbon, or other processes that produce CO2, such as breathing, two Oxygen atoms, or sometimes just one, attaches to one Carbon atom, so the gas you are looking for is Oxygen.
You may also be interested to know that about 96% of all global emissions of CO2 come from natural sources, i.e. not humans.
Thanks Gary and Kwik, I’m trying to make some sense of which gases are increasing and which are decreasing, obviously there’s a lot of people who only want to talk about co2. You see the co2 graph everywhere but you rarely see the o2 or the whole picture.
Gary Mount says:
September 11, 2011 at 10:17 am
You may also be interested to know that about 96% of all global emissions of CO2 come from natural sources, i.e. not humans.
___
Ah, but what a difference that 4% anthropogenic source has made…giving us 40% more CO2 in the atmosphere in just a few hundred years…sort of like compounding interest.
Richard111 says:
September 11, 2011 at 10:15 am
I find some of the comments here beyond strange.
Since when did H2O need CO2 to absorb infrared?
_____
CO2 and H20 have their own properties, independent of each other, however, one is a condensing greenhouse gas (H2O) and one is not (CO2). Best to read this, for a full understanding of why that distinction is vitally important to keeping Earth from being a ice-house planet:
http://www.giss.nasa.gov/research/briefs/lacis_01/
Tim Spence;
CO2 sits at 400 PPM and O2 sits at about 209,460 PPM. If Co2 were 500 PPM and the extra 100 displaced O2, then O2 would drop to…. 209,360 PPM.
and now you know why they keep calling it a “trace gas”
http://en.wikipedia.org/wiki/Atmosphere_of_Earth has a decent break down.
Bart says:
September 10, 2011 at 6:43 pm
tallbloke says:
September 10, 2011 at 11:17 am
“Over on Climate audit, Bart has found some tight relationships too…
http://climateaudit.org/2011/09/08/more-on-dessler-2010/#comment-302767“
I do hope people will go take a look. I believe I have found something very significant.
I’ve collated the disparate comments you’ve made on CA and Roy’s blog here:
http://tallbloke.wordpress.com/2011/09/11/bart-cloud-feedback-is-negative-ocean-response-is-around-4-88-years/
My comment there offers a possible reason for the ~5 year lag.
neill says:
September 11, 2011 at 7:51 am
“Does the represent, or possibly so, a ‘holy grail’ that skeptics have been seeking that would somehow establish negative feedback for clouds, a sort of brake on the climate system, under both increasing and decreasing temperatures?”
I think so, though I need other knowledgeable people to become aware of the result and determine what the effect of a -9.5 W/m^2/degC feedback would be. I think, though, that the IPCC models require the overall feedback to be positive to get any significant warming, so it appears to me that this result could, potentially, kill CAGW.
There could be a valid criticism that the span of data is too short to have high confidence in the result. But, I would argue that the onus is on them to prove that the overall feedback is positive, because I think this establishes that the running assumption should be that it is likely negative.
It’s GREAT to see all this science discussion bye those who previously would not dignify WUWT with their privileged presence. Thank you Dr. Spencer for forcing these people out of their arrogance and into some truly scientific questions regarding global climate. /sarcon So the science was settled eh ? /sarcoff
@R. Gates says: September 11, 2011 at 11:49 am
“Ah, but what a difference that 4% anthropogenic source has made…giving us 40% more CO2 in the atmosphere in just a few hundred years…sort of like compounding interest”
———————
Of fourse “R Grates” you know nothing of the sort re: 40% , you really do not know why the natural level of CO2 is increasing or if it came from mankind or another natural source over the past few 100 years.
Seems to me some pretty knowledgeable folks at Climate Audit are in a stir over this.
CAGW’s 9-11?
That criricism would apply equally to any position.
Mark
That last bit addressed to Bart.
Mark
R. Gates:
You really are a poser and your recxent post to me admits you are a liar.
At September 10, 2011 at 6:35 am you said to Richard Verney:
“As the climate is a system existing on the edge of chaos, it is taken as a given that no model will be able to predict those inherently unpredictable tipping points exactly.”
And at September 11, 2011 at 12:43 am I responded by
(a) pointing out that no climate model predicts any “tipping point” “exactly” or otherwise
and
(b) asking you to list the “tipping points” you fear because I know of none.
Your reply at September 11, 2011 at 9:24 am is pathetic.
It says:
“First of all, It is impossible to predict tipping points in a non-linear dynamical system on the edge of chaos.”
In other words, you agree that you lied when you suggested the climate models predict “tipping points” but not “exactly”.
Then you say:
“That has to do with the general warming of the Arctic and melting of permafrost and release of both additional CO2 and methane from both land and under the oceans as the region warms. We don’t know exactly where the “tipping point’ might be, but there is some average land and ocean temperatures at which larger and larger amounts of methane and CO2 will be released from both land and sea floor in and around the Arctic. This will of course lead to additional warming, leading the release of more methane and CO2, and so forth. This is no different that what the general Milankovitch forcing does at it forces more CO2 from the oceans at the beginning of an interglacial to start a positive-feedback warming process, only it would be much greater. So this Arctic warming/permafrost/methane clathrate feedback could easily represent a tipping point. Now, if such a tipping point did occur, it would dramatically alter the trajectory of our current warming, and looking back into the paleoclimate record, we’d be looking at temperatures more like the Miocene.”
In other words, YOU DO NOT KNOW OF ANY “TIPPING POINTS” but you think there “might” be one that may result from melting of permafrost.
And you conclude;
“But the point is, no model can predict this tipping point…ever, and the best guide we have is looking at the Earth’s past when similar atmospheric composition was seen.”
So, you admit that your original post was a complete falsehood: THERE ARE NO KNOWN “TIPPING POINTS” AND NO MODEL PREDICTS ANY.
As for the paleo past, the Earth had both warmer and cooler periods with much, much higher atmospheric CO2 concentrations than anybody ‘projects’ for the foreseeable future.
In summation, your post at September 10, 2011 at 6:35 am to Richard Verney was a set of lies and you should apologise for it (but I predict that you won’t).
Richard
R. Gates says:
September 11, 2011 at 11:49 am
Gary Mount says:
September 11, 2011 at 10:17 am
Ah, but what a difference that 4% anthropogenic source has made…giving us 40% more CO2 in the atmosphere in just a few hundred years…sort of like compounding interest.
=======================================
Except one works logarithmically downwards, and one works logarithmically upwards.
….. and that would be assuming your premise was correct in the first place, which it isn’t.
Wrong squared in one sentence, eh ?
Wrong cubed if you include the “difference” comment.
Maybe you need a rest.
Bart. I’ve been following this closely since you made your initial posting the other day on CA. A brilliant flash of insight. I agree – this could be the end of CAGW. And what a happy day that will be…
Jim Petrie
We already have two negative feedbacks operating.
Way back before the onset of photosynthesis the atmosphere must have contained at least 10% of CO2 and less than 1% of oxygen. This follows from the fact that oxygen is a very reactive chemical – much more so than CO2.
Over the millennia most of the CO2 in the atmosphere has been taken up by plants.
It is now a trace gas – one molecule in every 2500.
With increasing CO2 we are getting increasing plant growth. This will go on till we get a new equilibrium.
The second feedback is temperature. As an object gets hotter it loses more heat. If earth warms, it will lose more heat to outer space
R. Gates says:
September 11, 2011 at 11:49 am
Ah, but what a difference that 4% anthropogenic source has made…giving us 40% more CO2 in the atmosphere in just a few hundred years…sort of like compounding interest………………………………….
And the flora of mother earth thanks us. I quite like it myself as well.