The Search for a Short Term Marker of Long Term Climate Sensitivity
By Dr. Roy Spencer. October 4th, 2009
[This is an update on research progress we have made into determining just how sensitive the climate system is to increasing atmospheric greenhouse gas concentrations.]
While published studies are beginning to suggest that net feedbacks in the climate system could be negative for year-to-year variations (e.g., our 2007 paper, and the new study by Lindzen and Choi, 2009), there remains the question of whether the same can be said of long-term climate sensitivity (and therefore, of the strength of future global warming).
Even if we find observational evidence of an insensitive climate system for year-to-year fluctuations in the climate system, it could be that the system’s long term response to more carbon dioxide is very sensitive. I’m not saying I believe that is the case – I don’t – but it is possible. This question of a potentially large difference in short-term and long-term responses of the climate system has been bothering me for many months.
Significantly, as far as I know, the climate modelers have not yet demonstrated that there is any short-term behavior in their models which is also a good predictor of how much global warming those models project for our future. It needs to be something we can measure, something we can test with real observations. Just because all of the models behave more-or-less like the real climate system does not mean the range of warming they produce encompasses the truth.
For instance, computing feedback parameters (a measure of how much the radiative balance of the Earth changes in response to a temperature change) would be the most obvious test. But I’ve diagnosed feedback parameters from 7- to 10-year subsets of the models’ long-term global warming simulations, and they have virtually no correlation with those models known long-term feedbacks. (I am quite sure I know the reason for this…which is the subject of our JGR paper now being revised…I just don’t know a good way around it).
But I refuse to give up searching. This is because the most important feedbacks in the climate system – clouds and water vapor – have inherently short time scales…minutes for individual clouds, to days or weeks for large regional cloud systems and changes in free-tropospheric water vapor. So, I still believe that there MUST be one or more short term “markers” of long term climate sensitivity.
Well, this past week I think I finally found one. I’m going to be a little evasive about exactly what that marker is because, in this case, the finding is too important to give away to another researcher who will beat me to publishing it (insert smiley here).
What I will say is that the marker ‘index’ is related to how the climate models behave during sudden warming events and the cooling that follows them. In the IPCC climate models, these warming/cooling events typically have time scales of several months, and are self-generated as ‘natural variability’ within the models. (I’m not concerned that I’ve given it away, since the marker is not obvious…as my associate Danny Braswell asked, “What made you think of that?”)
The following plot shows how this ‘mystery index’ is related to the net feedback parameters diagnosed in those 18 climate models by Forster and Taylor (2006). As can be seen, it explains 50% of the variance among the different models. The best I have been able to do up to this point is less than 10% explained variance, which for a sample size of 18 models might as well be zero.
Also plotted is the range of values of this index from 9 years of CERES satellite measurements computed in the same manner as with the models’ output. As can be seen, the satellite data support lower climate sensitivity (larger feedback parameter) than any of the climate models…but not nearly as low as the 6 Watts per sq. meter per degree found for tropical climate variations by us and others.
For a doubling of atmospheric carbon dioxide, the satellite measurements would correspond to about 1.6 to 2.0 deg. C of warming, compared to the 18 IPCC models’ range shown, which corresponds to warming of from about 2.0 to 4.2 deg. C.
The relatively short length of record of our best satellite data (9 years) appears to be the limiting factor in this analysis. The model results shown in the above figure come from 50 years of output from each of the 18 models, while the satellite range of results comes from only 9 years of CERES data (March 2000 through December 2008). The index needs to be computed from as many strong warming events as can be found, because the marker only emerges when a number of them are averaged together.
Despite this drawback, the finding of this short-term marker of long-term climate sensitivity is at least a step in the right direction. I will post progress on this issue as the evidence unfolds. Hopefully, more robust markers can be found that show even a stronger relationship to long-term warming in the models, and which will produce greater confidence when tested with relatively short periods of satellite data.
Leif Svalgaard (15:27:01) :
Richard (14:58:41) : “People do not release the ideas they are researching generally before they have finished.”
Worse, they seem to release their results before they have finished…
Not their results Leif – just their hunches, maybe the results wont mach their hunches, maybe they will.
RR Kampen
This post
“First temperature rises due to long term Milankovitch (and such) effects. Vegetation and sea start releasing CO2 with a lag. This CO2 immediately helps to rise the temperature. From about a third of the climbing trajectory to interglacial maximum this CO2 becomes the dominant driver for further warming. The lag has then disappeared and temp and CO2 appear to rise simultaneously then – but in fact temp lags CO2 by a small time.”
Someone made fun of it with a “you just made that up” comment but the truth is you didn’t. This is a notorious claim often used by the AGW religion. It is also completely unsupported by the data but none the less is widely made.
As has been shown and discussed on previous threads here even the idea of CO2 increasing and adding to the warming is not supported. In fact cooling occurs routinely in the record during periods of at or near peak CO2 levels.
A claim that CO2 caused cooling would fit the paleo record better.
I agree.
If you want to chuck a half formed idea about this kind of blog is ideal, all sorts of well informed people with all sorts of experience and ideas only too willing to discuss and debate.
Which helps test, try and shape up or reject notions which need further development.
But if you have something worth publishing then do so, on here if you wish. Do not do a dance of the seven veils, that is for novelists, movie makers and the like. For the hype rarely lives up to the reality.
Kindest Regards
Leif,
I love you man, but I really think that Dr. Spencer is doing his science where the rubber meets the road ie, Earths radiation vis a vis transiate warming and cooling. That is where this whole warming/cooling thing is happening.
Dr. Spencer doesn’t present his new found index as absolute science, he is only clueing us in to what he’s looking at right now.
Is that “classical science”, you are right, it is not. But since when has science had such important ramifications? Also Dr. Spencer is developing “tech groupies” (like me) I enjoy him taking us along on his thought processes.
Even if you don’t like a reputiable scientist “teasing”, you should agree that when Dr. Spencer gets where he is going, it’s pretty solid science.
George E. Smith
Sorry for the typo’s.
As Obi-won-Kanobe said, “the MTF, that’s a term I’ve not heard for a long time”. It’s been a long time since I was involved in non-linear optics, & 2D analysis. And yes I did use the FFT for the conversion to and from the frequency domain in the above analysis.
What I liked about Fourier filtering, looking at long term temperature sets, was it extended the filtered results to the end points. That is, closer to the most recent end point, better then the MOV or standard recursive filters. Besides I could do the analysis on EXCEL using VB, as I gave away my MATLAB and statistical processing packages away years ago.
Any comments on the results?
The Economist has bought into the CO2 scare hook, line and sinker. You don’t have to register to vote for a comment on this page: click. Pick your favorite[s]. Or, register and set them straight.
Roy Spencer (04:51:16) :
Ok, I’ll take a shot at it.
The CO2 warming models predict changes in the heat energy transportation systems. They do this wrongly by making CO2 a ferocious warming feedback.
Along comes these sudden warming events, SST’s & El Nino’s and they do persist then fade off. But, in the absence of reversal effects, they leave the Earth warmer. They ‘step it up’.
What I believe you are up to is to use the changes to the Earth as predicted by the models to look for the natural ‘smoking guns’.
One could do the same by making a forced cooling model and look for what it does to the Earth, then find some key natural ‘ice makers’.
That’s what the models are useful for: simulated warmer Earth complete with altered heat energy transportation systems.
One might open an even bigger can of worms than AGW, but the pursuit of knowledge is a rocky road.
Wondering Aloud 16:19:04
Yes, we just don’t know, do we. Could be the next great meme: Demonize fossil fuels because CO2 causes Global Cooling.
====================================
Personally Smokey I write the Economist real letters.
And sometimes they even publish them.
But I agree this issue has really gone into La La land, to the point that it is hard to know quite what to say.
Still if there is obviously nothing more to be said some damn fool has to say it, that is usually me.
But then I always was a spoilsport, party pooper I think you say in the USA.
I mean everybody is so happy terrifying themselves with the AGW fantasy…….and too drunk on it’s delicious spine chilling horrors to worry about the bill. [ US check?]
Kindest Regards
…after reading all of these comments, I seem to have forgotten what the subject of this thread was. 🙂
Your nice little marker mark reminds one of the almost uslessly predictive trend-line drawing of stock technical analysis. What is to say that the graph is not two little J’s or a very sheared W or one 140 degree angle or whatever? If you showed more years you would see the trend is unmistakably anomalous, expand it out more and the GW becomes a dead vertical straight line at the end when only a single ice age in view. Consider that your entire graph (encompassing pretty well about the total period human forcing was more important than variations in natural forcing) would fit in less than 6 pixels width of the same graph rescaled between the last glacial maximum and the end of the glaciation. The same is true if the graph showed the time since humans had been evolved to survive on anything but hunting and gathering. There are certainly important natural forcers that vary from one year to the next, like the solar cycle (currently way down), volcanos – besides humans; and humans produced far less CO2 this year than nature – but the problem is that the human one is the only one that never changes sign. This is a constant presence. All on top of the much bigger water vapor GH contribution. The natural things are already in natural equilibrium, have been for 10,000 years, adding even part in 100 more watts/m^2 will cause a new equilibrium high enough to be important. It even takes a few centuries just to change to the new unnatural equilibrium, and even longer (thousands of years) to go back to the normal one. And the equilibrium we’re shooting at (what, 9 billion people, billions more industrialized on fossil fuel than today) finds every port in the world underwater: Tokyo.. New York.. London.. Hong Kong.. Rotterdam.. Venice.. New Orleans, 20/40 ft of sea level rise by the 23rd century.
In defence of Dr Spencer posting ‘clues’ about what he has found.
This is how science happens. A scientist guesses, intuits, or discovers by chance something unexpected. He investigates, and if he is right, gets the evidence necessary to publish.
Dr Spencer is clearly part way through this process and ‘excited’ that his intuition is panning out.
Reading between the lines, it’s a significant scientific advance in understanding climate. I hope we see the details soon.
rbateman (16:44:52) :
Roy Spencer (04:51:16) :
I can forsee there be difficulties in this approach.. which exists for the existing empirical data sets.,,, the resolution/ or time scale of accurate enough data to observe the smoking gun.
For example, basic agw= more co2 = more water vapour= a slightly raised lower barometric pressure?… but i dont believe for example that the data exist’s one way or the other for this.
in saying that… im a farmer, what the hell do i know 😉 Good luck Dr Spencer with yer research. I look forward to reading of it in the future.
Jeff L (12:55:26) :
Bravo!
Chris
Norfolk, VA, USA
Roy Spencer (17:18:17),
You’re right, I’m one of the guilty parties. I was jumping around between threads and posted assuming I was on the Copenhagen thread. That’s what I get for assuming. My apologies.
Richard (16:08:39) :
Not their results Leif – just their hunches, maybe the results wont mach their hunches, maybe they will.
The difference is too subtle for most people, including me.
DGallagher (16:25:45) :
Dr. Spencer doesn’t present his new found index as absolute science
He does not present his index, just some conclusions [and perhaps even that is too strong] based on a secret recipe. For us to follow along and evaluate/criticize/support/elaborate/inspire we need to know the details. Without that, he is in the league of Piers Corbyn. [expecting heat and grief from both sides.]
Leif Svalgaard (15:27:01) : “Richard (14:58:41): ‘People do not release the ideas they are researching generally before they have finished.’
Worse, they seem to release their results before they have finished…”
If they actually finished, they might look at their confidence intervals and see they don’t have anything to release. Better to publish right away and lock up their data.
jorgekafkazar (18:19:31) :
If they actually finished, they might look at their confidence intervals and see they don’t have anything to release.
The take advantage of the thousands of eyeballs this blog offers, Roy should have included enough details about the index that we can meaningfully participate [we don’t need to know the nitty-gritty].
One thing is for sure, if a sensitivity marker is being sought, it ain’t the Arctic sea ice. It sucks as any kind of marker. Let’s examine the data behind the trace that indicates we are somehow below normal and outside the two standard deviation, and should therefore run around saying, “The Arctic is melting! The Arctic is melting!”
There are 14 different Arctic areas that are monitored and that have enough of an average base that current levels can be compared to this average. Of those 14 areas, only 5 are demonstrating below average ice conditions. So it is misleading to read an overall trace (like the one to the right) and say that we are below normal. It is more accurate to say that the sea ice in the Chukchi Sea, East Siberian Sea, Laptev Sea, Kara Sea, and the Arctic basin are below normal.
Now overlay the swirling and powerful vortex winds in these areas listed above, and it is quite clear why these 5 areas are not icing up along an average path. The ice is being created, only to be pushed somewhere else by the wind.
Could this explain the crickets chirping when I bring up the fact that the Arctic is not melting like it should when in an AGW crowd? Yep. The crowd has moved over there by the treering stand and they appear to be drinking coolaid made out of sawdust. No ice.
Or for, say, Swiss patent clerks?
Here is my WAG:
Dr Spencer wrote on his blog a thread entitled “Brutal Cold in the IPCC Models versus Nautre” dated January 9, 2009.
http://www.drroyspencer.com/2009/01/brutal-cold-in-the-ipcc-models-versus-nature/
Speaking about brutally cold arctic air masses:
“…rather than being dry because it is cold, the air instead becomes cold because it is dry. And the reason the air is so dry is because it has been slowly sinking from high in the atmosphere, where there is very little water vapor. And why is THAT air so dry? Because precipitation processes have removed the water vapor as relatively warmer and moister air ascends in low pressure areas — snowstorms — which move around the periphery of the high pressure zones that are created by the strong cooling.
So, ultimately, it is precipitation processes in regions remote from these cold high pressure areas that mostly determine how cold surface temperatures will get. ”
So his marker must be related to the low pressure areas ( snowstorms?)around these cold high pressure areas. How that would relate to long term climate projections I do not know.
Re:
J. Bob (08:57:54) :
A Comparison of EMD & Fourier Filtering for Long Term Global Temperatures.
J. – You are on to something (IMHO). I have actually been working on some signal analysis techniques to determine various forcings. I can’t give away all my methods (ala Spencer :)) – much to the chagrin of Lief, I am sure) but I am doing some research which hopefully will move towards publication over the next couple years ( I have a regular job & do this is my spare time).
As a geophysicist, I am approaching this as a signal analysis problem, which I haven’t seen done to date (at least not in the way I am approaching it). The whole issue of CO2 forcing (& other forcings for that matter) is very similar to a geophysical inverse problem, as it relates to seismic data.
In a seismic inversion problem, you have an observed signal that is a function of time – analogous to our temperature signal vs time (or any other climate signal you want vs time).
This signal is the convolution of the earth’s reflectivity (analogous to our climate system) with a source of energy (analogous to a “forcing” in the climate system).
In the geophysical inverse problem , you are trying to figure out the earth’s reflectivity – done through a process generally known as deconvolution. Analogously, if we can deconvolve the temperature signal, we can figure out fundamentally how the climate system responds to different forcings. ….. this may be what Dr Spencer is doing & has beat me to the punch for all I know.
The climate system problem is more difficult because of potential non-linearities (which will show up as non-stationarities in your analysis), but as you have discovered, on the time scales of interest, the signal appears fairly stationary. The geophysical inverse problem is generally assumed to be linear (although in reality it isn’t exactly linear).
A couple suggestions:
1) Instead of a linear removal of the DC shift, use a logarithmic residual, using the end points of the signal – this will simulate removal of logarithmic CO2 signal. Do analysis similar to what I did in an earlier post ( Jeff L (12:55:26) 🙂 & see what you come up with for a CO2 forcing in terms of deg C per doubling – having done this myself, I know you will come up with a number with in the range of Spencer’s hypothesis
2) Plot your frequency results as 1/x – years per cycle vs cycles per year will be much more intuitive to your typical audience.
3) Calculate the spectra of potential forcings & compare to the spectra of the temperature signal – you will see some interesting correlations.
Have fun with it!
Jeff L (20:16:11) :
I have actually been working on some signal analysis techniques to determine various forcings. I can’t give away all my methods (ala Spencer :)) – much to the chagrin of Lief, I am sure)
That’s quite alright 🙂 because you are not making any claims here [yet] about results.
Fred Lightfoot (09:44:25) :
Artic sea ice????
Watching the Russian RT channel in English on Saturday they showed a one hour program on a team that have just returned from the North Pole (magnetic) driving 2 trucks (homemade), they had big flotation tires and trailers, never found any water but did encounter lots of broken pack ice. I have given up on the BBC, RT gives you the world news without the BS
Just a few months late.
Jason (17:18:21) :
The natural things are already in natural equilibrium, have been for 10,000 years,
What equilibrium?
Look at this holocene time versus temperature anomalies plot:
http://upload.wikimedia.org/wikipedia/commons/c/ca/Holocene_Temperature_Variations.png
Mind you, the average of the different measuring methods is misleading, because there is also an error laterally mostly unknown, so follow one of the colored lines and talk of equilibrium for ten thousand years.
This dismisses your prophecy:
adding even part in 100 more watts/m^2 will cause a new equilibrium high enough to be important. It even takes a few centuries just to change to the new unnatural equilibrium, and even longer (thousands of years) to go back to the normal one. And the equilibrium we’re shooting at (what, 9 billion people, billions more industrialized on fossil fuel than today) finds every port in the world underwater: Tokyo.. New York.. London.. Hong Kong.. Rotterdam.. Venice.. New Orleans, 20/40 ft of sea level rise by the 23rd century.
even if your other math were correct.
The probability that temperatures will naturally zoom down is so high, from the above linked plot to make any human induced changes irrelevant. The plot says: no equilibrium and rule except what goes up must come down.