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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danapplelope
please note the inline replies above, you apparently keep missing them
I take off for a day and come back to find Dr. Spencer announcing he might have found a short-term marker for climate variance. Excellent! I would have thought comments would be more speculative to his mystery marker, yet we have trolls, religion, and ‘when weather is not climate’ talk. Joy of joys.
Anthony, look at it this way, pro-agw websites are dead in my opinion and seriously lack readership because ‘singin to the choir’ must feel a bit lonely. On the otherhand, websites that offer a scientific method of approach to climate, weather and FACT based commentary attracts the ‘concensus is in’ bunch. While their attempts must be from pure boredom, their recognition of sites like yours only confirms one thing for me: The debate is far from over.
This website, from top to bottom, is the most professional on the web. That includes you, all of the guests that post here and the majority of the commentators.
I applaude you all. The rest of you disruptive, troll bound, brainwashed believers of Gore/Hansen/Jones need to be patient and respect the efforts of everyone involved here at WUWT.
With that said. I can’t wait for Dr. Spencers official unveiling of his secret marker. Sounds facinating. I wonder if he’s been talking to … oh nevermind. :-p
1 Dr Spencer is looking for the long term climate sensitivity index
2 Realists / Sceptics will be very pleased to see his conclusion
I have no idea why AGWs always assume that sceptics are searching for the dis-proving of their religion.
Sceptics are trying to apply real science to the problem no matter what the outcome. Scepticism is science not religion.
Hey Anthony, look at it like this, Pro-AGW trolls must feel threatened by the scientific method and a website like yours, that I believe to be the most professional being done on the web, regarding climatology. They don’t know science and more importantly, the method of fact-finding. Maybe, just maybe, the ‘when climate is not weather’ gang are recognizing that no one is listening to them, no matter how loud or disruptive they become.
Now if I could get back to the topic at hand. What does Dr. Spencer have for a short-term marker. I can’t wait !
Has he been talking to Timo Niroma by chance? I would really like to see someone make some ground breaking research based on statistical formulations that Niroma has suggested in his work regarding Jupiters effect on Earths climate. But that’s just me.
-David Alan-
Philip_B (21:26:54) :
“And I’d add, that if the value is found in the climate models, then that is the proper function of the climate models, to indicate where to look for climate relevant values in the real world, and not to make climate predictions.”
When I was deeply involved in modeling, many lifetimes ago, they were always used to *study* the behaviors of things.
We would take observations, and try to replicate what we observed in the model, usually with mixed success.
Where we found discrepancies, we would play with the models – by adding constants or additional variables – in an attempt to remove the discrepancy. This process invariably lead to insights about whatever it was we were modeling.
Because most natural phenomena are cyclic in nature, you are never sure what frequencies are present in the observed “waveform” of variations, so you play with Fourier transforms to find the fundamental frequencies associated with unknown influencing factors, etc.
So if we did attempt predictions, they always contained “secret ingredients” in the form of frequencies for factor-x, factor-y, etc.
These predictions were to test the model, to see what we might have missed in our understanding of how much we didn’t know.
Am I wrong in being worried that climate modelers might have a whole alphabet of “secret ingredients”, and yet they are still happily making predictions as if they were absolute fact, when at the end of the day, they don’t know swat?
Hmmm, I’ll wait ’til Spencer comes clean 🙂
Personally, I don’t see the point in questioning why the models diverge from reality. They are fundamentally flawed, being politically driven ,,, apart from anything else.
danappaloupe (23:56:14) :
The real important characteristic of ice as it applies to climate change is the volume of ice, expressed in thickness.
http://nsidc.org/arcticseaicenews/faq.html#really_declining
From the link:
A recent study suggests that 5,500 years ago, the Arctic had substantially less summertime sea ice than today.
This seems to indicate that there is substantial natural variability in Arctic sea ice regardless of co2 levels.
Enough of danappaloupe for this thread, he/she has been offered their own thread by Anthony (I wonder if I could get the same opportunity by using similar tactics).
Let all play Dr Roy’s guessing game as a mentally stimulating exercise. I think the mystery marker is not a biological one, since the models don’t include them. It could be to do with atmospheric circulation, atmospheric angular momentum anyone?
There may be a major effort on part of the team to discredit this and CA sites> BTW major story at CA again maybe someone would like to put it in laymans terms.
Dr Spencer,
Thanks for the preview, looking forward to seeing it in print.
danappaloupe (00:20:54) :
I am not a fan of pointing out the “500 pound gorilla in the room” …
But we have one.
1. Welcome to WUWT – you will find much more open debate and discourse than at other sites (for instance RC, where numerous postings never see the light of day).
2. It’s good to have some dialogue and debate about a range of subjects and the vast majority of posters here will join in; yes it can get a bit lively but hey, that’s good.
3. If you’re really serious about this and don’t want to be labelled as a ‘troll’ then please start things off on the right foot; avoid comments like “…which does bring into question to intellect of the readership…” and dismissing people like Dr Roy Spencer because he happens to be religious. Would you walk into a bar you’ve never been in, stroll up to the mike on the stage and announce to the clientelle that they’re all dumb because of their choice of music? Hardly.
(For information, I am an atheist, engineer with an astrophysics degree and I don’t feel the need to dismiss someone (in a verbal/written context) on religious grounds. In another forum I’d quite happily have the debate – but not in this one.)
You say “Not a single person has stepped up and addressed the issue that many people on this website believe, wrongly, that one year of weather data can be used to draw conclusions about climate, global warming, models etc. That is the only thing I care about.”
Maybe that’s because you started off badly. Your statement above puts words into people’s mouths and that’s never a great way to start a debate. If you do some back-reading you will find lots of climate-vs-weather topics and arguments going on. Simply strolling up and making an unfounded, ill-researched, statement is not going to engender a discussion.
I would recommend the following: take Anthony up of his offer of a thread – that’s a pretty good deal and gives you the floor; you will have contribution and debate for sure then. You can include in that debate on ice-cover the merits of using the last couple of years’ worth of data in comparison to the 30 years’ worth of accumulated measurements; which introduces your core interest. Go for it – I would!
For my part – does one year’s worth of weather countermand longer term trends in the Earth’s climate? No, of course not and I don’t think you’ll find many people who disagree with that. When that year of measurment turns into 2, then 3, then 4 etc. then I think you can have that debate – see the global temps over the last 6-10 years. Does this mean I think we’re heading for an ice age? No. Does this mean I think that the warming and doom-n-gloom has been totally overplayed? Yes.
So take Mr Watts up on his offer and lets all get stuck into the debate :o)
(My apologies to Anthony if this is OT for this thread.)
Cheers
Mark
One thing I’ve noticed, trolls never see themselves as trolls… however, changing the subject or worse, attempting to “educate” regulars at any blog is usually the main sign of a troll.
Also, many of the warmists don’t seem to understand that people they dismiss as “skeptics” or “deniers” are actually mainly concerned with finding out the truth (aka Science) as opposed to dogmatically believing very non-credible “peer reviewed papers”. Yes, we prefer to think for ourselves instead of allowing people with questionable motives to be the gatekeepers of human knowledge.
There is absolutely NO scientific endeavor that cannot be understood by the “common man”, if it is explained properly. Any time you claim that nobody other than a group educated a certain way can possibly understand something, you have already lost your argument, and you are wrong.
I have yet to see a CAGW promoter who has more knowledge about the Science than the average “skeptic”, for the simple fact that the CAGW promoters are more willing to be led down the garden path without asking questions.
danappaloupe (00:20:54) :
I am not a fan of pointing out the “500 pound gorilla in the room” …
But we have one.
Not a single person has stepped up and addressed the issue that many people on this website believe, wrongly, that one year of weather data can be used to draw conclusions about climate, global warming, models etc. Even if we were talking about a climate model that we know is wrong, and designed it to be wrong, we can’t judge that model based on one year of data.
Well, it might be a defect in your eye, because I do not see anybody on this board saying that one year’s data determine the climate. Please give links to your assertions.
Ten years now is another story.
danappaloupe (23:50:21) :
I The publisher of this blog is not interested in sparking good debate. There is no debate on this blog as a consequence and it is has become a place of talking points and partisan politics, yet is touted as a science blog (and a best one at that!).
As someone who regularly disagrees with the publisher and many of the readers of this blog, I have to say your statement is total garbage. If you want talking points and partisan politics (includig heavy censorship of opinions) – try RealClimate or Tamino’s blog.
I’ve been banned from Tamino’s blog for suggesting that there might be an ocean influence in the late (and early) 20th century warming. He did actually allow me to post for a while until I provided strong evidence and he realised his own ideas and those of his fan club were probably wrong.
Realclimate rarely allows any post which it recognises as damaging to the ‘consensus’ view – unless they have a satisfactory response, that is. In general, though , posts are either not published at all or else published days later when the topic has gone ‘cold’. There was even the occasion, some years ago, when I posted a list of studies countering the H-S reconstruction, but – overnight – the whole thread disappeared due to a “technical hitch”. Clearly someone hadn’t been watchful enough and had allowed something they shouldn’t to be published. If I remember correctly, someone recovered the cached files. I think Steve Milloy might have been involved.
There is no comparison between the policies on this site or CA with those of the main pro-AGW sites and you clearly have no idea what you’re talking about. Nevertheless, you’ll probably still be allowed to post here.
Anthony: your troll policy is remarkably enlightened. Another reason why this blog is so productive and congenial. Thanks.
Regarding the “mystery index” that shows 5x previous correlation with models– I humbly await further revelation. I imagine it’s a blend of things: “take 2 pinches of albedo, mix in 0.6 of average tropopause temperatures, allow to marinate overnight with average velocity of jetstream, subtract the square root of Michael Mann’s credibility, and serve hot.”
danappaloupe (00:20:54) :
Here
Re: Claude Harvey (22:23:48) :
I have no idea what the man is talking about, but I’m guessing the recent jump in satellite measured temperature at the 14,000 foot level that he regularly tracks along with the recent SST numbers has given him pause to reflect. I suspect the “skeptic” community will not be delighted with Spencer’s eventual unveiling of his latest theory.
There is a new channel for SST on the MSU webpage. SST are heading down again, watch the air temps going the same soon.
While the climate models assume a constant relative humidity which leads to positive feedback when temps rise (and therefore should lead to negative feedback when temps fall which they never mention) they have never actually made the case for their conjecture much beyond the assertion that it is so.
The models aren’t gridded fine enough to really analyze it anyway so their fallback position is, as always, that any deviation from the mantra is merely weather noise and they are dealing with climate.
Note danappaloupe’s statement: “your readers need to be educated about the difference between weather and climate”. ::snort::
Gavin insists that though the climate models fail with short term forecasting (weather), their predictions, excuse me, projections about the long term (climate) are correct.
That’s why what spencer is doing is so darned important. If a rise in CO2 levels is really going to have a severe impact on future weather* then there must logically be some way to tease out the evidence even in the short term. We should be able to identify and quantify something that is occurring RIGHT NOW that will show us not only what may occur re temp, but how long it will take.
—–
*there is no such thing as weather now, climate later. That’s merely an obfuscatory construct giving the impression that natural variation will end. Its mirror is the flattening of the MWP to remove natural variation in the past.
Can we kill this off instead just by saying that nobody who is interested in scientific truth thinks that one year of weather data is important. But many politicians, celebrities, journalists and come scientists need constantly reminded of that too. It’s just too easy for them to assume or loudly hint that man has caused event x,y, or z when neither the science nor the simplistic models even vaguely support such a premise. If danappaloupe or anyone else needs an example of such hypocriticalconfusion he can head off to Bill Maher’s blog where he that we are all idiots if we don’t see that the recent Australian drought was “climate change” in action and that we are idiots to believe that a very harsh Winter cooling means climate isn’t changing and that by the way us idiots shouldn’t be confusing weather with climate. Ho ho! Cue the braying of sheep! There are so many example of this one-sided thinking to choose from: Just pick almost any article about climate change anywhere.
Weather and climate are chaotic by nature hence you have to look at long term trends and sort out the natural from the man-made. The separation part isn’t easy because we don’t know why we slipped into a little ice age in the first place. Hence to assume all recent warming is due to man – as apparently Spencer has done above – is facile. The long term trend part however is fairly easy. By looking a trends it seems there has been no discernible increase in any extreme weather events anywhere – despite the acknowledged warming. Ergo man needn’t be assumed to be a part of any zero trend in extreme weather events. So if any visiting scientists here would help kill off this persistent rumor that wild weather events are getting worse and man is causing it then the science would be healthier. Unfortunately it was climate scientists who started this baseless rumor in the first place.
Re: wattsupwiththat (23:45:27) :
Any source you pick, NSIDC or JAXA shows the same result: More ice in 2009 than 2008, more ice in 2008 than 2007. If you are able, interpret these two graphs.
—
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.
“yet is touted as a science blog (and a best one at that!).”
I think someone has blog envy, and is desperate to get in on the action.
[Reply: It is not ‘touted’; WUWT won this year’s “Best Science” category in the Weblog Awards. Click on their icon on the upper right of the page. Compare the results to RealClimate. ~dbs, mod.]
Lets look at this from first principles. The chosen index of long term warming is surface temperature – at least that chosen by the IPCC, doubtless because of its direct relevance to human life and ecosystems. Changes in surface temperature over several decades is primarily a consequence of cloud cover and humidity, with an element of aerosols that deflect sunlight, coupled to the regular solar cycle variation of 0.1% insolation (and any potential electro-magnetic effects on cloud seeding or electrical effects on aerosols).
Thus, if we identify a short-term (2000-2008) relationship, we have to show how it can be continued over several decades – either increased or decreased. In the time period of data that Roy Spencer has at his disposal, there is a transition from one solar maximum to one solar minimum. I can’t see how he is going to derive an indication of the direction that this decade’s data might go in. The next solar cycle will likely be down on the previous (electromagnetically), and the transition is a long one – thus lengthening the period when solar insolation is slightly reduced (note that other work has shown that surface temperatures respond to the 11-year solar cycle and that the scale of response suggests an amplifier in addition to the change in short-wave radiation at source – the 0.1%).
The past surface temperature data for centennial scale changes show evidence of cycles and thus the chief candidates for long term change – cloud, aerosol and water vapour, ought to reflect those cycles – but we have limited data. The main long cycles are 400/800 years (LIA/MWP), 70 years (Arctic Oscillation, AMO) 30-40 years (PDO) – and the satellite era really only covers the last one’s positive phase.
So – whatever the short-term indicator is, we have to know how it relates to the drivers of these cycles.
Here is my cent’s worth (which I outline in my book, ‘Chill’) and for which I would dearly like some discussion: in the short term, the primary area of interest should be the pulse of SW radiation to the equatorial regions of the ocean surface where heat is first stored within the planetary system. Cloud cover in this area will modulate that heat store – less cloud, more heat stored. If we look at several decades of surface temperatures in the ENSO region, for example, and look less to the ‘trend’ but to the rising amplitude of the ENSO pulse (which may now be declining), then we see that the heat is not stored in that region. A glance at the spatial distribution of the global upper ocean heat stores shows that they are not homogenous but concentrated in the gyres of the northern Pacific and Atlantic basins.
We now know (thanks to Compo and Sardeshmukh) that 80% of land surface temperatures are driven by transfer of heat from the oceans. The main transfer is via westerly ‘winds’ in the northern hemisphere. These winds are driven by the jetstream – but they are not so much winds, as vortices or cyclones, that extract the heat, create cloud and dump the heat as rainfall or radiative cloud cover on land. The ‘unusual’ Arctic melt-down has been partly driven by excess radiative cloud over the polar region (14% from 1980-2000) and warm ocean water travelling further north than usual under the sea-ice.
When there is more cloud in higher latitudes (and the gyres are located between 30-60 degrees north) the effect is warming – insulation of the ocean heat stores, rather than cooling as in the tropics. So any change in percentage cover OR spatial distribution will affect those heat stores.
In my view, therefore, Roy must relate the short term indicator to these long term ocean dynamics to get a real-world understanding of the long term changes. I don’t think the climate models he refers to even attempt to model these ocean dynamics.
Clearly, some short term (decadal) variable has created the build-up of heat in the oceans – and I would suspect the amplitude of the ENSO cycle is the primary driver, with the warm water pulses it creates being redistributed northward (and southward too, but more readily dissipated in the southern ocean circumpolar current where there is a net heat loss and no continental constraints that create large gyres).
If we are now entering a longer term cooling, then we should look for a signal that shows a) depletion of the northern gyres’ warm water pool; b) changes in cloud, storm tracks and wind patterns in relation to those gyres (especially the track of the jetstream). Ultimately, i suspect that it is the latter, which the work of Drew Shindell at NASA (I keep mentioning this but nobody seems to know what happened to the line of research) showed was correlated with a variable of solar output (UV light), that determines the long term pattern of build-up and depletion of upper ocean heat stores.
Scaling. The lead graph is visually deceiving simply because the total Y axis range is only 1 degree showing departure from 0 change. The average caveman would not know how to interpret the graph. Accompanied by a press release stating that up is bad and down is good, we end up being beaten to death by club wielding cavemen.
Apologies if this is slightly off topic, and let me preface it by saying I have an enormous amount of respect for what Dr Roy has done and the integrity he has shown in doing it.
I don’t pretend to know enough to debate Dr Roy on climate, or even to fully understand what he is looking for here, but the thing that has struck me most about the climate issue is the close correlation between the PDO cycles and temperature since 1880. So far we have had 3 warm cycles and 2 cold cycles, and are just beginning the third cold cycle.
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.
If this third cycle plays out like the rest, and all other things being equal (which of course, they won’t be), then temps will have risen by about 0.8 degC over 150 years, and CO2 will have risen by about 50%.. Is it not fair to say that only that 0.8 degC is up for grabs as far as figuring out what other forcings/feedbacks are at play?
Anthony
An adaptable explanation of agw/climate change (up)?
http://go2.wordpress.com/?id=725X1342&site=wattsupwiththat.wordpress.com&url=http%3A%2F%2Fblogs.abc.net.au%2Fqueensland%2F2009%2F10%2Fa-new-economic-theory-the-magazine-cover-index-.html%3Fprogram%3D612_otf
A new economic theory – The Magazine Cover Index
Oct 05, 2009
Ever wanted to find out which way the markets were moving – housing or stocks and shares?
There’s plenty of advice around, but who do you believe?
We have one man who says it’s really quite easy. Chris Leithner’s theory suggests that all you have to do is look at what the magazine covers are saying – and then do the exact opposite….
Audio on site
I just put this up on Tips, but in the face of some I’m reading above it might fit here – snip if not.
RR Kampen: all of the ice that is in the Arctic today will be a year older and much thicker after this winter is over?