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.
A little OT
A little routine I usually use to get a preview:
1. Using a text editor, create a document and save it as type .htm
2. RIGHT click on the testdoc.htm you just saved and choose EDIT from the menu.
3. Type your text [using whatever html tags you feel necessary].
4. SAVE the testdoc.htm
5. Now “DOUBLE CLICK” to OPEN it. It will open in your browser, and, hopefully show if further EDITing is necessary.
Your testdoc.htm can be re-used as necessary.
Roy Spencer (17:18:17) : …after reading all of these comments, I seem to have forgotten what the subject of this thread was. 🙂
I am a bit slow in the intake but I think that maybe a gentle hint that we are slightly off topic/ track?
Right. Now what was it? – The search for a short term marker for Long Term Climate Sensitivity? – thats it methinks.
So here’s the task for the brighter guys and girls on here – Guess what that short term marker might be and Guess why it may be a marker for long term sensitivity and how this could be proved, how would one search for it, what would it show …
Have I got that right or am I way off the mark?
Leif stop your one liners on how things should be done and buckle down to it…
Could it be the three month running average applied to the temperature series like it is done for SST? Does it demonstrate a statistically predictable path? NOAA does both a dynamical set of models as well as the tried and true statistical models to predict what the sea temps will do next. The dynamical models are based on systems knowledge and understanding (which is in its infancy). The statistical models are based on what has happened before given the same set of system circumstances. Could this be a home for a temp marker? Running statistical models are not very computer intensive and I could imagine a statistician building a 3 month running average model for temps.
Re: Jim (08:29:27) :
“By what stretch of the imagination was 2007 a disaster WRT ice? Were people killed. Did polar bears go extinct? Did a bunch of animals die or any species go extinct? What’s up with that??”
—
It was disastrous ref the ice. How picky you are!
Re: Wondering Aloud (16:19:04) :
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.”
—
I posted a reference. Can you point out the fallacies in that article, please? Here is the link again: http://icebubbles.ucsd.edu/Publications/CaillonTermIII.pdf .
As stated previously I would go for the latitudinal position of the ITCZ and try to ascertain it’s position when the Earth is in a neutral energy balance. It would be at neutral some distance north of the equator because of the preponderance of ocean surfaces in the southern hemisphere.
I’ve no idea whether that is what Roy has in mind though.
Apparently it was just on the equator during the depths of the Little Ice Age, moved significantly north of the equator during the recent warming and has now pulled back equatorward a little once more.
I regard it as a suitable proxy for the net latitudinal position of all the air circulation systems combined.
Incidentally the position of the ITCZ on the equator in the LIA is good evidence for a 500 year or so ocean cycle because we have all seen that the air circulation systems respond to changes in sea surface temperatures. That is now very apparent from study of ENSO events and the longer term PDO phase shifts. It seems also to apply from LIA to present times
Thus we are clearly dealing with multiple overlapping ocean cycles on at least 3 time scales namely interannual for ENSO, multidecadal for PDO phase shifts and half a millennium for each phase of the long term background trend.
Any need for another primary forcing from sun, GHGs or anything else is looking less and less necessary as time goes by.
Tom in Florida
“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. ”
Oh my. This is weird (to me) because I’ve been thinking of ‘climate’ in terms of where the highs and the periphery lows set up, but not thinking about intensity or moisture content or whatnot.
But highs and lows seem to be in the air, so to speak. Just today while following different blog posts, comments, and links and trackbacks I stumbled across a link to the weatherchannel blog. I discover that Stu Ostrow is no longer a skeptic and he just posted on highs and lows. Anomalous highs and increase in 500mb heights in the NH mid to high latitudes. And, further, associated cut-off lows with anomalous rainfall. Lots of examples.
“The atmospheric warming has resulted in an increase in 1000-500 millibar thicknesses. Those increased thicknesses are manifesting themselves primarily by an increase in 500 mb heights (particularly notable in mid-high latitudes of the Northern Hemisphere), as there has not been a similar rise in 1000 mb heights. Although there is of course natural year-to-year variability, the overall trend at 500 mb has clearly been upward.”
http://www.weather.com/blog/weather/8_20427.html?from=hp_news3
I certainly think Dr. Spencer would be interested…
Re: tallbloke (09:19:55) :
“And this one confirms what all the others say: that co2 lags temperature all the way to the top of the curve. Fig 4 shows the 40Ar curve and the co2 coincident, but this is because the co2 curve has been shifted 800 years to the left.
Next!”
—
No, we have to remain.
Please interpret fig. 3 (it is above fig. 4). Please point out how the interpretation in the article (quoted below) is inferior to your diametrical hypothesis. Please explain how your hypothesis may relate to the icebubble findings in the article. In short: how come you and this article conclude oppositely on the basis of the same empirical evidence?
“CO2 is not the forcing that initially drives the climatic
system during a deglaciation. Rather, deglaciation
is probably initiated by some insolation
forcing (1, 31, 32), which influences first the
temperature change in Antarctica (and possibly
in part of the Southern Hemisphere) and then the
CO2. This sequence of events is still in full
agreement with the idea that CO2 plays,
through its greenhouse effect, a key role in
amplifying the initial orbital forcing. First, the
800-year time lag is short in comparison with
the total duration of the temperature and CO2
increases (5000 years). Second, the CO2
increase clearly precedes the Northern Hemisphere
deglaciation (Fig. 3).”
RR Kampen (03:41:03) :
Re: Wondering Aloud (16:19:04) :
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.”
—
I posted a reference. Can you point out the fallacies in that article, please.
Let me save Wondering aloud the trouble, as I already addressed this paper, but RR didn’t reply.
RR Kampen (08:10:43) :
E.g., http://icebubbles.ucsd.edu/Publications/CaillonTermIII.pdf .
Any short search will yield results, by the way.
And this one confirms what all the others say: that co2 lags temperature all the way to the top of the curve. Fig 4 shows the 40Ar curve and the co2 coincident, but this is because the co2 curve has been shifted 800 years to the right.
Syl says:
(1) The climate models don’t ASSUME constant relative humidity. Rather, this is something that is an output of the models given the physics that goes into them. (Actually, I think on average the models tend to show a little bit of a drop in relative humidity as the warming occurs.)
(2) You are wrong about the idea that the feedback is negative when temps fall. The feedback is positive in both directions, meaning that it magnifies the change. So, when temperatures warm, the amount of water vapor increases and this causes further warming. When temperatures cool, the amount of water vapor decreases and this causes further cooling. In both cases, the initial change is amplified and the feedback is thus positive.
(3) Contrary to what you say, there is now considerable empirical support that the water vapor feedback is acting about as the models predict. See http://www.sciencemag.org/cgi/content/summary/sci;323/5917/1020
Innocentious:
The NASA GISS Model E is available for download here: http://www.giss.nasa.gov/tools/modelE/
I also believe that the NCAR Community Model is available.
The assumption that the models make is that CO2 has the radiative absorption bands that it is known to have from laboratory measurements.
Re: tallbloke (06:13:54) :
—
“Let me save Wondering aloud the trouble, as I already addressed this paper, but RR didn’t reply.”
—
Our replies crossed, mine is just above your post.
Dr. Spencer:
In previous work looking at short-term feedbacks using the satellite data, I seem to recall that you diagnosed a climate sensitivity of ~0.7 C per CO2 doubling. Here, however, for the long-term feedback, I noticed that you are talking about a feedback of 1.6 to 2.0 C per doubling, which is basically right next to the bottom of the IPCC “likely” range of 2.0 to 4.5 C. Am I understanding correctly…and what is the difference that leads to these higher sensitivity estimates?
“It was disastrous ref the ice. How picky you are!”
Don’t you guys reaalize how terrible that melting was for the ice… Yes I know it happens every year, and then ice returns every year… But that one year… Oh my… that poor poor ice… Oops… I just had a terrible disaster right here in my iced tea glass… Going to the freezer for more ice…
Mike Bryant
PS you guys need to be a little more sensitive to ice’s feelings…
hunter says:
You are misrepresenting what people have noted in regards to Dr. Spencer. Here is the piece that he wrote in his column at Tech Central Station: http://www.tcsdaily.com/article.aspx?id=080805I
Note that he is not stating his personal theistic beliefs but rather is talking about science and saying that “intelligent design, as a theory of origins, is no more religious, and no less scientific, than evolutionism.” I think it is fair to ask whether this, in one’s own view, shows good scientific judgment or not. Obviously, opinions on that will differ.
Joel,
Warming at the surface produces more convection, upward radiation and water vapour which produces more cloud (after an initial reduction in low cloud) followed by more cooling rains with increased windiness and a generally accelerated rate of energy transfer from surface to space via an energised hydrological cycle.
They are all negative processes far outweighing any greenhouse effect from variations in humidity. Indeed it appears that the system does not allow much increase in humidity. Instead the hydrological cycle speeds up and restrains any increase in humidity so even the proposed positive feedback from the assumed extra humidity just doesn’t happen.
The empirical evidence in support of what I say is the recent failure of the globe to keep warming up and the relative stability of the humidity figures despite increasing CO2.
Furthermore the poleward latitudinal shift in the air circulation systems during the past warming spell must have some significance and cannot be ignored. The only possible significance is a change in the speed of the hydrological cycle sending the excess energy to space faster which is, again, a negative feedback.
Warming creating more warming ad infinitum in an ever increasing spiral just doesn’t happen, there is no empirical evidence to support it yet that is at the heart of AGW theory.
Quite ridiculous and it is for the warmists to justify it not for others to rebut it. Anyway the real world is trashing the idea day by day.
Jeff L – What I am getting at, is establishing long term direct temperature data sets (200+ years) to form a basis of comparing it against other data sets ( long term sunspots, PDO, etc.). In addition, building a set of systematic analysis tools, of which the Fourier is but one of the main tools. Finally, establish a set of cross checks on the data analysis, such as comparing the Fourier analysis with the recursive filters “filtfilt”, or what ever.
It’s been a few years since I looked at deconvolution, but we used it in image analysis, especially compensating for blurring and movement. The “Textbook of Astronomical Image Processing”, by Berry & Burnell, is a good start. If you have access to MATLAB they have a image toolbox that might help.
With tree ring saga going one now, I’ll post a example, a little later, showing how one of my long temperature sets compares against the one of the tree ring sets.
I also agree with your points. Comparing PSD plots is a excellent method of correlation. It saved our hides in more then a few cases, in orbital vehicle design.
Re: Mike Bryant (06:57:31) :
“It was disastrous ref the ice. How picky you are!”
Don’t you guys reaalize how terrible that melting was for the ice… Yes I know it happens every year, and then ice returns every year… But that one year… Oh my… that poor poor ice… Oops… I just had a terrible disaster right here in my iced tea glass… Going to the freezer for more ice…”
—
Apparently you’ve never heard of ‘catastrophe theory’. Its mathematics. “Catastrophe theory analyses degenerate critical points of the potential function.” From http://en.wikipedia.org/wiki/Catastrophe_theory .
How happy I am to have been able to enlighten you to this concept, complete with the great illustration of Arctic sea-ice where ‘thickness = 0.5m’ is one of those ‘degenerate critical points’!
So little time and so much quality blog, what to do?
Leif:
I will check again thru my papers, but I don’t think Shindell ‘based’ his work on the Schatten and Hoyt TSI – though obviously he would have used it as that was pretty much the standard for the time he was publishing. I will revisit but here is my understanding:
* he discovered a link between the solar cycle and the movement of the jetstream (the latter based upon sediment studies of the LIA)
* he observed heat transfer from the stratosphere to the troposphere due to UV from the solar cycle – which varied by 8% over the cycle – much more than SW radiation at 0.1% (does that still stand?)
* he theorised that this transfer affected the polar vortex and this was what pushed the jetstream south
* he then extrapolated this knowledge to the LIA/solar history and the sedimentology that showed a prolonged shift in the jetstream over the LIA time period
So – as long as there was some minimalising of solar output – especially UV during the LIA, it doesn’t really matter how far out H&S were on TSI. Unless I am out-of-touch and the current low at solar minimum, does not entail a significantly lower UV from the solar peak?
My argument is that in normal cycles each solar peak cancels out the cooling effect from the solar minimum, but any prolongation of the minimum – as we have seen now for 2 years, will lead to a shift in the extractive vortices that track the jetstream – especially if that minimum is prolonged for 50 years. It may then take several hundred years to recover! the drop globally is 0.5 C, but regionally, in the NE Atlantic for example, in some places it was 3 C.
Have you got a sense of what the UV component looks like over the relevant time periods?
Phil in California:
Would love to meet up with Stephen Wilde – I am in Somerset. My email is on my website: ethos-uk.com and it would be great to see you if you do come over – my life as an analyst when there is an elephant in the room gets a bit lonely!
PS
Elephants, even in the living room, are a fact of life on the planet, as are emperors with new clothes…….and I should not complain, all will pass!
Claude Harvey (14:09:15) : “Re: jorgekafkazar (11:52:46) : ‘I feel like I’m participating on a moot debate about how many angels can dance the kazatsky on a PhD’s pate.’ JK
“Now there’s a sane voice amidst a cacophony of tail-chasing dogs!” CH
Thanks for the pseudocompliment, but in future please do not lop off part of my sentences, thus taking my remarks out of context and altering their meaning. That is all too typical of the unethical behaviour we’ve learned to expect from warmist trolls. Misquoting in this or any other form is unacceptable. [You should, at the very least, include ellipsis (…) to warn the reader that something has been removed.]
My full sentence started with: ‘In a way, since this is all supposed to devolve around GCM’s, ‘ GCM’s are already politically-driven drivel, in my opinion, and need no further discrediting.
Stephen Wilde: You are correct about the increase in the hydrological cycle. However:
(1) The only way for the earth to interact with space in terms of energy flow is through radiative heat transfer. Hence, it is not directly relevant to this how the convective flows within the atmosphere work except to the extent that they affect heat transfer back out into space (or affect the amount of radiation from the sun that gets to the troposphere). And, they do affect heat transfer because in the tropics, the upper troposphere around the effective radiating level warms more than the surface, which means that the surface does not need to warm as much as one might expect in order to restore radiative balance. This results in a negative feedback called the “lapse rate feedback” that takes back part of the positive feedback due to the water vapor feedback alone and is included in all of the climate models. In fact, while the climate models tend to disagree somewhat on the strength of the positive water vapor feedback and negative lapse rate feedback, the ones with a larger magnitude water vapor feedback tend to have a larger lapse rate feedback and vice versa, because these feedbacks are essentially controlled by the same convective processes. As a result, the different models agree much more closely on the strength of the sum of these two feedbacks than they do on the strengths of the two independently.
(2) As for the empirical evidence for the water vapor feedback happening about as predicted by the models, see http://www.sciencemag.org/cgi/content/summary/sci;323/5917/1020
In fact, there is empirical evidence. E.g., there is empirical evidence for the water vapor feedback as I gave a link to above, and there is empirical evidence from the response of the Mt Pinatubo eruption and the temperature change from the Last Glacial Maximum to now to support a climate sensitivity in the range that the IPCC says. (Note, however, that your “ad infinitum in an ever increasing spiral” may be a source of confusion…It is true that it can be thought of as “ad infinitum”, but the mathematics is one of a converging series like the geometric series 1 + 1/2 + 1/4 + 1/8 + …, which, despite being an infinite series, converges to the finite value of 2. So, the result is amplification of the response in the absence of feedbacks, not a runaway increase in the temperature.)
Joel Shore (07:01:48) :
“intelligent design, as a theory of origins, is no more religious, and no less scientific, than evolutionism.” I think it is fair to ask whether this, in one’s own view, shows good scientific judgment or not.
Any ‘theory’ that ignores the facts [as ID does] cannot be called science, and someone adhering to it does not show good scientific judgment. This is not a question about opinion. One cannot have opinions about gravity, relativity, evolution, etc as these are facts and facts just are, and are not subject to opinions.
******
DGallagher (11:14:08) :
Remembering Dr. Spencer’s past work and current position, I would hazard a guess that the index is a ratio of the rate of change of the anomoly of radiation to the rate of change of the temperature anomoly.
******
DGallagher, that’s what I think too.
We shall see….
COMPARING TREE PROXIES and LONG TERM TEMPERATURE DATA
****Jeff L ****
Here is a sample of what I was talking about above.
With the debate about tree ring data and “global warming, I though I’d compare tree ring data to long term temperature data. The tree ring data I found from http://www.climatedata.info
With tree ring Nor. Hem. proxy data shown below, using the 20 year MOV Norway, Sweden & Russian data, since they were more compatable to Ave14 defined below:
http://www.climatedata.info/Proxy/Proxy/Proxy/treerings_northern.html
Next I took the 14 longest temperature records from http://www.rimfrost.no/
plus the east English data starting in 1659. I averaged the whole bunch up to form a composite average Ave14. This is shown below:
http://www.imagenerd.com/uploads/ave14-smoothed-rev_cheb-j0m9Y.gif
I then added 40 year filtering consisting of a MOV, Fourier filter, and a 2 pole reverse Chebushev filter. The later is found in MATLAB as “filtfilt”. Basically the later filter is run forward and then backward to compensate for phase delay. Unfortunately the end points generally will have a significant error, but is a good cross check for date in the middle of the sample. The Fourier gives much better end point results, comparable to the EMD method.
The figure below compares the 20 year MOV averaged tree ring data with the 20 year MOV Ave14 data. The tree ring width is plotted against temperature.
http://www.imagenerd.com/uploads/ave14-tr-noswru-C3EAh.gif
For what it’s worth, it’s in the region where it “kinda looks” correlated, but would need more sophisticated analysis to show anything definite. From this short analysis, if I were a betting man, I’m not sure I”d bet the chicken coop on tree ring data, much less the farm .