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.
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Joel (0859:52)
1) The models do not have the right numbers because they underestimate or ignore the variable rate of energy emission from the oceans arising from the 30 year PDO phase shifts (or the likely 500 year cycle). All they have at present is a guesstimate arising from the interannual ENSO cycle.
Furthermore they have made no account of the effect of shifts in the latitudinal positions of all the air circulation systems beyond normal seasonal variations which prevents destabilisation at the ocean/air interface.
Additionally they do not fully take account of variability in air circulation near the top of the atmosphere which adjusts the rate of energy emission to space so as to prevent destabilisation at the air/space interface.
The numbers are ,quite simply, incomplete and even the most recent coupled models do not deal with those matters.
2) Increased evaporation and more water vapour is led by warming just as CO2 levels are. They then go on to cause net cooling as a negative feedback. The idea that the net feedback is positive I do find outlandish. Overall Pinatubo was a cooling phenomenon. You seem to suggest it caused warming. The recovery from the glacial maximum was solar/orbital induced yet you seem to suggest it was caused by more water vapour. I find both those suggestions equally puzzling.
On Dr. Spencer’s mystery that he sets us, here is a conjecture;
The burning of sequestered hydrocarbons will result in the sequestration of the necessary amounts of atmospheric oxygen; firstly into atmospheric CO2 and then out of the atmosphere into oceans, biomass, etc. The resulting loss of oxygen from the atmosphere, and also the CO2, ought then to appear as a reduction in global total atmospheric pressure.
The consequences of reducing that amount of molecules of oxygen from the atmosphere ought to include an overall reduction in sea-level air temperature due to the adiabatic effect; i.e. the effective raising of sea-level pressure altitude with the thinning of the atmosphere will produce an overall drop in air temperature at the surface. Global cooling? (My preliminary headscratchings indicate around – 0.8 deg C from anthropic causes)
This reduction in average pressure ought to increase average evaporation, and so cloud-cover, which might be measured in the short-term. Also, a global increase in effective pressure altitude might advance the start of the snowfall season, and also advance the thaw season due to faster ablation. Both of these effect might be observable from records of satellite images. ( … so my money is on a stash of old photos … )
And as an aside, barometric pressure readings have been, and are, recorded to the same geographic resolution as temperature, and have a similar historical record, it is possible to produce a history of ‘average global atmospheric pressure’ analogous to ‘global average temperature’.
We could see some very interesting linkages between these records, unless it has already been done and dusted. ( I speculate idly that Anthony’s surface temperature work might well be aided by co-analysis of the co-located pressure and humidity readings.)
Stephen Wilde says:
If there is a variable rate of energy emission because of PDO, you presumably mean that PDO was transferring energy from the oceans to the atmosphere over the last ~30 years. If that is so, why did both the atmosphere and oceans warm (with ocean warming both determined by direct measurements in the upper oceans and inferred from the change in seal level due to thermal expansion)?
Actually, I think the models do in fact show latitudinal shifts in circulation patterns. And, I don’t know what you mean by the “variability in air circulation near the top of the atmosphere”. The models do show the vertical profile in the tropics changing approximately according to moist adiabatic lapse rate theory, which is why there is a negative lapse rate feedback. What is your evidence that they are not fully accounting for this? (Note in fact that those who believe that there is no “hot spot” in the tropical troposphere are essentially arguing that the negative lapse rate that exists in the models does not seem to be manifest in the real climate system, which is the opposite of what you seem to be saying, although I think they are probably wrong and the issue is instead one of data quality for the multidecadal trends.)
It is not outlandish at all. It is simply a consequence of the greenhouse gas properties of water vapor. (The feedback due to changes in the condensed water vapor, i.e., clouds is more complicated both because clouds affect incoming solar radiation in addition to decreasing outgoing longwave radiation and because it is not trivial to predict how clouds will change in a warmer world where both the temperature and absolute humidity increase such that the relative humidity is more-or-less constant.)
No, I am not suggesting that at all. Mt Pinatubo caused cooling because it injected material (aerosols or pre-cursors to aerosols) into the atmosphere that reflected some of the solar radiation. And, this cooling was amplified by feedbacks in the same way that warming due to increasing CO2 (or increased solar irradiance or whatever) is amplified by feedbacks.
What I am suggesting is that it was triggered by orbital changes although the main global forcings (which, depending on context, you could also call “feedbacks” on the original orbital effect, which caused almost no change in global mean annual forcing but significant changes in the latitudinal and seasonal distribution of the forcings) were the decrease in albedo due to melting ice sheets and vegetation changes, the increase of greenhouse gas levels, and a decrease in aerosol loading.
However, just as in the current case, water vapor and cloud feedbacks operated. And, since we can estimate the global radiative forcings due to the albedo change, greenhouse gas change, and aerosol change and we have a pretty good estimate of the global temperature change, that allows us to estimate the climate sensitivity in units of C / (W/m^2). Finally, since we know what the radiative forcing due to a given change in greenhouse gases such as CO2, that allows us to estimate the climate sensitivity to a doubling of CO2 levels.
I have no idea of the short term marker in climate models which would lead to longer term sensitivity to greenhouse gases.I think that climate is finely balanced between the cold polar regions and the warm equator because of where we are in the holocene interglacial period, it takes very little to swing the balance one way or the other as we have seen in the MWP the LIA and the recent modern warm period. Solar activity , volcanoes and other things all are important in changing this balance
Sorry Joel but your fixed line of thinking prevents you from interpreting and evaluating my points correctly so I’ll have to draw a line here.
It would take me too long to disentangle your misapprehensions and this is not a suitable venue in any event.
Let the real world inform both of us over the coming few years.
Leif says:
Of course, you won’t get any argument from me on this. I tried to phrase what I said very non-judgmentally given the sensitivity that Anthony and the other moderators have shown in the past about avoiding having arguments break out about the merits of evolutionary theory or intelligent design.
Reply: Thanks Joel, I know you were trying. ~ ctm
RR Kampen (05:57:03) :
Re: tallbloke (09:19:55) :
http://icebubbles.ucsd.edu/Publications/CaillonTermIII.pdf
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.
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?
I didn’t put forward a hypothesis. I just pointed out the error in your reading of the paper you linked to. Please admit that your claim to which I was responding was based on a misinterpretation of fig4:
RR Kampen (05:50:56) :
“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.”
It doesn’t. You failed to spot the shift of the co2 data by 800 years in the graph.
Didn’t you?
paulhan (04:35:34) :
I believe I am right in saying that none of the models Dr Roy refers to take into account the effects of the PDO, so if his analysis doesn’t have some element of the PDO effect, it strikes me as a bit of a wild goose chase.
Dr. Roy is involved in measuring the earth’s radiation from space, and how the radiation changes in response to temperature changes. Climate models also need to calculate the amount of heat radiated under various conditions. Dr. Spencer can therefore compare how closely the models behave like the real thing in terms of how heat is radiated.
Dr. Spencer is looking for some type of behavior that both models and nature exhibit, that reveals itself in the short term, and is also predictive of the amount of “warming” that will occur over the long term. Identifying short term indicator could be huge, a real sanity check on all the climate models.
What’s intrigueing is that whatever such a short term indicator may be, it has to be related to the mechanism that causes long term warming in the models. If there is a strong correlation, then somewhere there must be a cause and effect.
Joel Shore (07:01:48) : 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: … 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 Shore dont get me wrong. I do not agree with Dr Spencer on what his opinions maybe on creationism, but that is irrelevant here. Discussion of religious issues is prohibited here, so that question is not fair to ask. What your opinions are on the matter raised by you, and it profoundly disinterests me, could be discussed on another blog.
You are misunderstanding the issue. What Dr Spencer says on the issues raised by him is to be judged on its own merits not on what he may have written elsewhere on another subject.
You do not discuss Newton’s Laws on the basis that he believed in Alchemy or was a theist. An Ad Hominem fallacy is to attack the man rather than the argument in question.
PS
I do not look on the matter pointed out in my above post as a call for intense discussion. Move on.
Leif Svalgaard (09:06:44) :
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.
————————————
Leif, I respectfully disagree, For me, the definition of science it that it makes testable predictions. Facts are not science, they are data. The theories of gravity and relativity make testable predictions.
[SNIP ~ as expected an ID discussion is starting to ferment. I’m stopping it now. Off limits, period. No one’s opinion’s on this subject are to follow ~ charles the moderator]
Note that these are my opinions. This is much closer to philosophy then to science. We should stick to discussing Dr. Spencer’s science not his philosophy/religion since that is the topic of this thread. For philosophy, I would suggest reading Mortimer Adler on “THE ETHICS OF COMMON SENSE”
(http://www.radicalacademy.com/adleroncomsen.htm) and stick to that in the discussions here as most of the posts do.
I find this to be a spectacularly informative site and never cease to be amazed at the information in the links pointed to by the posters including Leif’s.
David.Gibson
David.Gibson (17:31:15) :
Facts are not science, they are data. The theories of gravity and relativity make testable predictions
It is always hard to be precise without being pedantic. The theories are of course not facts, but they say happen factually occurs. Apples fall to the ground, moving clocks go slower, […] is actually occurring, etc. That’s were the fact are, and all these theories are very successful in predicting things that actually happen. In a sense, the theories are but a shorthand [or a label] for all the facts they explain and predict come to pass. And they are more, they are ‘executable’ shorthands. When you feed data or conditions in, they give you data or conditions out, that correspond to actually happened or will happen. It is in this sense that I replace the whole long-winded explanation just above with saying that the theories are ‘facts’ or ‘factual’ if that is more palatable.
DGallagher (15:37:51) :
Dr. Roy is involved in measuring the earth’s radiation from space, and how the radiation changes in response to temperature changes. Climate models also need to calculate the amount of heat radiated under various conditions. Dr. Spencer can therefore compare how closely the models behave like the real thing in terms of how heat is radiated.
..
What’s intrigueing is that whatever such a short term indicator may be, it has to be related to the mechanism that causes long term warming in the models. If there is a strong correlation, then somewhere there must be a cause and effect.
Not necessarily
David.Gibson (17:31:15) :
Facts are not science, they are data. The theories of gravity …
To clarify, I did not speak about ‘theories of Gravity’, etc. I said:
“One cannot have opinions about gravity, relativity, […], plate tectonics, etc as these are facts and facts just are, and are not subject to opinions.”. I added PT.
All of those things are facts. There is a ‘theory of Gravity’ [there are several actually], but that does not mean that Gravity is not fact. Gravity is a fact. If you don’t believe drop a brick on your foot. The theory is ABOUT this FACT. And so on for all the other items I mentioned [and many more, of course]. You should not confuse the fact X with the theory of X.
Or the fact X that I froze my tush and tootsies off in 18 degree snowy weather, with the theory of X, this past weekend in NE Oregon.
Richard (18:45:01) :
“If there is a strong correlation, then somewhere there must be a cause and effect.”
Not necessarily
Isn’t it amazing that it is necessary to state that?
Leif, it is necessary but not sufficient. Heh.
===========================
Pamela Gray (19:04:13) : Or the fact X that I froze my tush and tootsies off in 18 degree snowy weather, with the theory of X, this past weekend in NE Oregon.
Oregon? Its cold here too down under.
“Pamela Gray (19:04:13) : Or the fact X that I froze my tush and tootsies off in 18 degree snowy weather, with the theory of X, this past weekend in NE Oregon.
Oregon? Its cold here too down under.”
See, your readers believe that one year of weather (data) can be used to criticize a theory of CLIMATE.
This is not an isolated incident and no one on here ever corrects them.
Also, must I explain why surface area of ice is a weak indicator of total volume of ice?
Re: tallbloke (15:06:05) :
It doesn’t. You failed to spot the shift of the co2 data by 800 years in the graph.
Didn’t you?
—
No. Let’s return to my earlier post on this subject, a reply for kim:
—
->
RR Kampen (05:50:56) :
Re: kim (05:19:27) :
“I’ve also wondered about the 800 year lag in the ice cores.”
—
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.
—
Now show me how the article disputes that.
Leif Svalgaard (18:55:12) :
David.Gibson (17:31:15) :
Facts are not science, they are data. The theories of gravity …
To clarify, I did not speak about ‘theories of Gravity’, etc. I said:
“One cannot have opinions about gravity, relativity, […], plate tectonics, etc as these are facts and facts just are, and are not subject to opinions.”. I added PT.
All of those things are facts.
To be fair to David.Gibson, you originally included a theory in this list which you have replaced with plate tectonics which was of a different order of abstraction than the others you mention.
It was once accepted scientific “fact” that the atom was the smallest possible elementary unit and that it was by definition indivisible. This is no longer a “fact”. Facts cannot be isolated from the value and quality laden linguistic continuum in which they are embedded. To claim otherwise is the fallacy of naieve realism.
An overly ardent belief in it is an impediment to scientific progress.
Some of todays “facts” will become tomorrows artifacts.
At moderators… Please leave away previous post, it contains a dumb error!
Repaired follows:
—
Couple of days ago I posted:
There was certainly less ice in 2008 than in 2007.
Not in surface area, correct.
But in the single important parameter here: ice VOLUME (correctly pointed out by danappaloupe) which is the product of surface extent and average thickness.
In 2008 over half the multiyear sea-ice left over from 2007 dissappeared: http://www.knmi.nl/cms/mmbase/images/29518 .
Whether the volume this year is again smaller than in 2008 will have to be awaited.
—
Waiting is over, volume is comparable to 2008 or might be a little larger. A new record low extent for >2 years old sea-ice, that is the thicker ice: http://www.eurekalert.org/multimedia/pub/web/17240_web.jpg .
While total extent remained slightly above the 2008 minimum the strengthened downward trend continues relentlessly.
RR Kampen (01:09:51) :
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.
—
Now show me how the article disputes that.
Easy, the very article you linked in support of the above proposition, which clearly shows the lag of the co2 curve only disappears when you shift it 800 years to the right as in Figure 4.
Co2 lags temperature at all timescales. This is easy to demonstrate.
Short term interannual fluctuation in temperature lead co2 response by around 9 months. Longer term temperature changes lead co2 by 800 to 2800 years as the Lassen ice cores show.
You guys keep trying to tell us the lag isn’t there but this is self delusion.
Next you’ll be trying to tell me Cuffey and Vimeaux solved the lag problem.
tallbloke (01:13:56) :
It was once accepted scientific “fact” that the atom was the smallest possible elementary unit and that it was by definition indivisible.
You are confused about the distinction between X and a theory about X. Atoms exist and that is a fact. That theory about the properties of atoms is correct at one level: atoms are the elementary units at ordinary amounts of energy. The theory breaks down and must be refined when we increase the energy with which we probe. The same with gravity, for example. The Newtonian theory of gravity also breaks down at some level and must be replaced by Einstein’s. That the theory needs to be refined does not change that gravity is a fact. The fact that the Earth is round was not negated when we realized that the Earth is slightly oblate, etc.
Joel Shore (06:33:06) look at what you say in your number 1 & 2, you contradict yourself.