These days, when global warming inactivists need to trot out somebody with some semblance of scientific credentials (from the dwindling supply who have made themselves available for such purposes), it seems that they increasingly turn to Roy Spencer, a Principal Research Scientist at the University of Alabama. Roy does have a handful of peer-reviewed publications, some of which have quite decent and interesting results in them. However, the thing you have to understand is that what he gets through peer-review is far less threatening to the mainstream picture of anthropogenic global warming than you’d think from the spin he puts on it in press releases, presentations and the blogosphere. His recent guest article on Pielke Sr’s site is a case in point, and provides the fodder for our discussion today.
Actually, Roy has been pretty busy dishing out the confusion recently. Future posts will take a look at his mass market book on climate change, entitled Climate Confusion, published last month, and his article in National Review. We’ll also dig into some of his peer reviewed work, notably the recent paper by Spencer and Braswell on climate sensitivity, and his paper on tropical clouds which is widely misquoted as supporting Lindzen’s IRIS conjecture regarding stabilizing cloud feedback. But on to today’s cooking lesson.
They call it "Internal Radiative Forcing." We call it "weather."
In Spencer and Braswell (2008), and to an even greater extent in his blog article, Spencer tries to introduce the rather peculiar notion of "internal radiative forcing" as distinct from cloud or water vapor feedback. He goes so far as to say that the IPCC is biased against "internal radiative forcing," in favor of treating cloud effects as feedback. Just what does he mean by this notion? And what, if any, difference does it make to the way IPCC models are formulated? The answer to the latter question is easy: none, since the concept of feedbacks is just something used to try to make sense of what a model does, and does not actually enter into the formulation of the model itself.
Clouds respond on a time scale of hours to weather conditions like the appearance of fronts, to oceanic conditions, and to external radiative forcing (such as the rising and setting of the Sun). Does Spencer really think that a subsystem with such a quick intrinsic time scale can just up and decide to lock into some new configuration and stay there for decades, forcing the ocean to be dragged along into some compatible state? Or does he perhaps mean that slow components,like the ocean, modulate the clouds, and the resulting cloud radiative forcing amplifies or damps the resulting interannual or decadal variability? That latter sounds a lot like a cloud feedback to me — acting on natural variability whose root cause is in the ponderous motions of the ocean.
Think of it like a pot of water boiling on a stove. What ultimately controls the rate of boiling, the setting of the stove knob or the turbulent fluctuations of the bubbles rising through the water? Roy’s idea about clouds is like saying that you should expect big, long-lasting variations in the boiling rate because sometimes all the steam bubbles will decide to form on the left half of the pot leaving the right half bubble-free — and that things will remain that way despite all the turbulence for hours on end.
The only sense that can be made of Spencer’s notion is that there is some natural variability in the climate system, which in turn causes a natural variability to some extent in the radiation budget of the planet, which in turn may modify the natural variability. Is this news? Is this shocking? Is this something that should lead us to doubt model predictions of global warming? No — it is just part and parcel of the same old question of whether the pattern of the 20th and 21st century can be ascribed to natural variability without the effect of anthropogenic greenhouse gases. The IPCC, among others, nailed that, and nobody has demonstrated that natural variability can do the trick. Roy thinks he has, but as we shall soon see, it’s all a matter of how you run your ingredients through the food processor.
The impressive graph that isn’t
So here’s what Roy did. He took two indices of interannual variability: the Southern Oscillation (SOI) index, which is a proxy for El Nino, and the Pacific Decadal Oscillation Index (PDOI). He formed an ad-hoc weighted sum of these indices,and then multiplied by an ad-hoc scaling factor to turn the resulting time series into a time series of radiative forcing in Watts per square meter. Then he used that time series to drive a simple linear globally averaged mixed layer ocean model incorporating a linearized term representing heat loss to space. And voila, look what comes out of the oven!
Roy is really taken with this graph. So much so that he uses it as a banner near the top of his climate confusion web site under the heading "Could Global Warming Be Mostly Natural?" But is it as good as it looks? To find out, I programmed up his model myself, but chose the set of adjustable parameters based on compatibility with observations constraining reasonable magnitudes for these parameters. Here’s what I came up with:
So why does Roy’s graph look so much better than mine? As Julia Child said, "It’s so beautifully arranged on the plate – you know someone’s fingers have been all over it."
A Cooking lesson
Lesson One: Jack up the radiative forcing beyond all reason. Reliable data on decadal variability of the Earth’s radiation budget are hard to come by, but to provide some reality check I based my setting of the scaling factor between radiative forcing and the SOI/PDOI index on the tropical data of Wielecki et al 2002 (as corrected in response to Trenberth’s criticism here.) The data is shown below. On interannual time scales, it’s mostly the net top-of-atmosphere flux that counts, so the curve to look at is the green NET curve in the bottom-most panel.
Except for the response to the Pinatubo eruption (the pronounced dip during 1991), the fluctuations are on the order of 1 W/m2 or less once you smooth on an annual time scale. Based on this estimate and on the typical magnitude of Spencer’s combined SOI/PDOI index, I chose a scaling factor (Roy’s a) of 0.27 W/m2 .. In his article, Roy uses a value ten times as big, but then he partly covers up how large the annual radiative forcing is by showing only the five year averages. With Roy’s value of the scaling coefficient, the annual radiative forcing looks like this
which is clearly grossly exaggerated compared to the data. Moreover, in my own estimate of the scaling factor I tried to match the overall magnitude of the fluctuations, whereas restricting the estimate to that part of the observed fluctuation which correlates with the SOI/PDOI index could reduce the factor further. Finally, even insofar as some part of climate change could be ascribed to long term cloud changes associated with the PDOI and SOI, one cannot exclude the possibility that those changes are driven by the warming — in other words a feedback. Still, let’s go ahead and ignore all that, and put in Roy’s value of the scaling coefficient, and see what we get.
So here’s our cooked graph as of Lesson 1 of the recipe:
Lesson Two: Use a completely unrealistic mixed layer depth. OK, so we’ve goosed up the amplitude of the temperature signal to where it looks more impressive, but the wild interannual swings in temperature look completely unlike the real thing. What to do about that? This brings us to the issue of mixed layer depth. The mixed layer depth determines the response time of the model, since a deeper mixed layer has more mass and takes longer to heat up, all other things being equal. The actual ocean mixed layer has a depth on the order of 50 meters. That’s why we got such large amplitude and high frequency fluctuations in the previous graph. What value does Roy use for the mixed layer depth? One kilometer. To be sure, on the centennial scale, some heat does get buried several hundred meters deep in the ocean, at least in some limited parts of the ocean. However, to assume that all radiative imbalances are instantaneously mixed away to a depth of 1000 meters is oceanographically ludicrous. Let’s do it anyway. After all, as Julia Child said, "In cooking you’ve got to have a ‘What the Hell’ attitude." Here’s the result now:
Lesson 3: Pick an initial condition way out of equilibrium. It looks better, especially in the latter part of the century. But it doesn’t get the trend in the early century right. Gotta keep cooking! The essential ingredient this time is the choice of initial condition for the model. If we initialize the anomaly at -0.4C, which amounts to an assumption that the system is wildly out of equilibrium in 1900, then this is what we get:
Now, it’s finally looking ready to serve up to the unsuspecting diners. Note that it’s the adoption of an unrealistically large mixed layer depth that allows Roy to monkey with the early-century trend by adjusting the initial condition. With a more realistic mixed layer depth, changing the initial condition on temperature anomaly only leads to a rapid adjustment period affecting the first few years.
My graph is not absolutely identical to Roy’s, because there are minor differences in the initialization, the temperature offset used to define anomalies, and the temperature data set I’m using as a basis for comparision. My point though, is that this is not an exacting recipe: it’s hash — or Hamburger Helper — not soufflé. Following Roy’s recipe, you can get a reasonable-looking fit to data with very little fine-tuning because Roy has given himself a lot of elbow room to play around in: you have the choice of any two variability indices among dozens available, you make an arbitrary linear combination of them to suit your purposes, you choose whatever mixed layer depth you want, and you finish it all off by allowing yourself the luxury of diddling the initial condition. With all those degrees of freedom, I daresay you could fit the temperature record using hog-belly futures and New Zealand sheep population. Anybody want to try?
Postlude: Fool me once …
Why am I not surprised about all this shameless cookery? Perhaps it’s because I remember this 1997 gem from the front page of the Wall Street Journal, entitled "Science has Spoken:Global Warming is a Myth":
That’s not Roy’s prose, but it is Roy’s data over there in the graph on the right, which purports to show that the climate has been cooling, not warming. We now know, of course, that the satellite data set confirms that the climate is warming , and indeed at very nearly the same rate as indicated by the surface temperature records. Now, there’s nothing wrong with making mistakes when pursuing an innovative observational method, but Spencer and Christy sat by for most of a decade allowing — indeed encouraging — the use of their data set as an icon for global warming skeptics. They committed serial errors in the data analysis, but insisted they were right and models and thermometers were wrong. They did little or nothing to root out possible sources of errors, and left it to others to clean up the mess, as has now been done.
So after that history, we’re supposed to savor all Roy’s new cookery?
That’s an awful lot to swallow.
Dhogaza, Agreed, it is mostly fundamentalist X-tians who advocate ID, although if they considered some of the theological implications, I think it would give them pause. My point was that we see as many loons on the ideological/religious/political left as on the right–and both are dangerous precisely because they see everything through ideological lenses. I am as wary of those who would use climate change to bring about a dictatorship of the proletariat as I am of those who deny climate change is occurring for theological or political reasons.
[Response: Well put. I would worry about the objectivity of a scientist who believed in ID as much as I would worry about the objectivity of a scientist who doubted that tobacco caused cancer. In either case, one needn’t go into the scientist’s religious beliefs. –raypierre]
I’m new here, and I’ve read Spencer’s book “Climate Confusion” and a few other books to learn about the subject. I have questions about the water vapor feedback.
In his book, Spencer’s scientific objections are neatly summarized on page 172-175. It seems mainly centered on his hypothesis that water vapor will provide a negative feedback so that as humans add more C02, causing warming, the water vapor will stabilize the global temperature. He was a little vague (to me at least) on how this would work — having to do with precipitation systems. For example, Spencer says on page 175, “I predict that there will be an increasing number of scientific publications in the coming years describing ‘newly found’ stabilizing processes in the climate system.” Is there support for this prediction ?
I also read Kerry Emanuel’s short book “What we Know About Climate Change”. Emanuel states that one can calculate that if we doubled the concentration of C02 and kept the rest of the system fixed, the Earth’s temperature would rise about 1.2 C. He writes that most of the controversy comes from knowing how much CO2 will indirectly cause other components of the system to change, the most important being water vapor, as Spencer’s book also says.
The “standard view”, writes Emanuel, is that the relative humidity remains approximately constant as the climate changes; therefore, as the temperature increases the water vapor increases, which further increases the temperature since water vapor is a greenhouse gas — hence, a positive feedback. Emanuel says this is supported by observations and models, but he admits that not everyone agrees.
I would like to ask two questions: 1) Is this CO2 forcing (deltaT = 1.2C for doubling man’s CO2 contribution) together with positive feedback from water vapor the main components in the model prediction for further warming by 1.5 to 4.5C by the year 2100, or is it a lot more complicated than that ? 2) How settled is it that the feedback is positive ? Does Spencer have a good point that it may well turn out to be negative ?
[Response: 1) yes – but you need to factor in ice-albedo and cloud feedbacks to get the whole range. 2) Very. The constraints come from paleo-climate records, and you can look up our previous discussions of climate sensitivity to get a handle on why (note that a climate sensitivity greater than 1.2C implies a positive feedback. In addition, the main feedbacks (WV and ice-albedo) have all been measured and validated in the field. Cloud feedbacks are the most uncertain factor. 3) No. Spencer appears to be indulging in wishful thinking in the absence of any evidence. – gavin]
[Response: Well said, Gavin. I’d add that, with regard to the water vapor feedback, it’s telling that even Lindzen has abandoned his earlier claims that water vapor would prove a stabilizing feedback. It is difficult to detect long-term trends in water vapor, but such measurements as there are tend to confirm an increase of water vapor, and rule out a stabilizing drying of the atmosphere. More importantly, the water vapor feedback is not put in the GCM’s by fiat, but rather emerges from large scale circulations and basic thermodynamics — and the patterns gotten from this physics agree well with detailed satellite observations of the present atmosphere (see e.g. my GRL papers with Roca and with Brogniez, among many, many others). Finally, if you took away a positive water vapor feedback, climate would be so insensitive to radiative forcing that it would become essentially impossible to account for climate change of the past century, the cooling during glacial periods, or Eocene warmth. For that matter, if you took away positive water vapor feedback, it would not only make it harder to explain 20th century climate variations using CO2, but it would make it equally hard to explain it by any of the alternate mechanisms the contrarians favor. Roy’s forlorn faith in a stabilizing water vapor feedback is intellectually bankrupt. Clouds are a different matter. While there’s no credible evidence for a significant stabilizing cloud feedback, one can’t easily rule that out on basic physical grounds. On the other hand, as ClimatePrediction.net showed, cloud feedbacks have the potential to make climate sensitivity much, much worse than the top of the IPCC range. So, if you are fairly dealing with that uncertainty, you have to weigh the small chance that clouds will save you against the small chance that clouds will cause utter catastrophe. –raypierre]
Ray Ladbury (#50): Do you really know of people “who would use climate change to bring about a dictatorship of the proletariat”? I can’t help thinking of Logan Pearsall Smith (yes, this is getting a bit far afield):
“You must beware of thinking too much about Style,” said my
kindly adviser, “or you will become like those fastidious people
who polish and polish until there is nothing left.”
“Then there really are such people?” I asked, lost in the thought
of how much I should like to meet them. But the well-informed
lady could give me no precise information about them.
I often hear of them in this tantalizing manner, and perhaps one
day I shall get to know them. They sound delightful.
When they stick to science, no. But both Spencer and (to a lesser extent IMO) Christy operate outside science, too, and both are open about their being part of the conservative wing of the Southern Baptist church and how faith influences their lives. Spencer was co-author of the letter signed by over 100 evangelicals (including himself, of course) disagreeing with the recent announcement by the leadership of the Southern Baptist Church that they accept the scientific consensus regarding climate change.
I don’t care about Spencer’s religious beliefs, but I *do* care about his political activities which are focused on trying to get people to ignore the problem, and his scientific work, part of which was the focus of the original post. He’s politically active in the Southern Baptist Church, and those activities (NOT his religion per se) are fair game IMO.
Ray …
Nothing to disagree with there, but the thread’s about Spencer’s work, and he’s not a part of the left (political, religious, ideological or otherwise). I pointed out his public support for ID to undermine his credibility, not the credibility of some of the more whacko people on the left etc. But if a thread pops up with such a person as its focus, you can depend on me to pile on.
Just what, a year or so ago, the specter was raised of some fearsome liberal climate dictator who was going to kill off a free peoples’ right to forever drive SUVs and pickups.
Today the CEO of Vespa (scooters are suddenly highly profitable) got major face time on a Wall Street TV show on the day that Ford announced major cutbacks in the production of SUVs and pickups.
This dictator better get his butt to the party.
> those fastidious people who polish and polish
> until there is nothing left.
I can give you an approximation on that. Somewhere, probably in a book I once read, found on a library shelf — but not apparently on the Internet, at least with a brief search — you’ll find a WW-II US Navy order banning the polishing of the brass inner doors on torpedo tubes on the diesel-electric submarines. They were before and early on in the war polished like all other Navy brass — until someone measured them and found they’d been cast barely thick enough for the pressure requirements, and were in danger of being polished to where they were below spec for safety.
It’s possible the people who give tours at those still afloat — one in San Francisco and one in Portland that I know of — can give you a reference on that one.
Maybe:
“The clearance between the outside diameter of the valve plate and the inside diameter of the upper head skirt is very critical. At the most, it amounts to only a few thousandths of an inch. Once established, it should not be altered. When it is necessary to remove corrosion from either part, it should, preferably, be chucked in a lathe, rotated at slow speed, and a very fine abrasive applied cautiously, as by a polishing cloth. It should be remembered that, although a slow and painstaking procedure is onerous, if this clearance once becomes too great the only remedy lies in replacing one or both of the parts, followed by a complete calibration check by the trial firing of torpedoes or dummies.”
http://hnsa.org/doc/fleetsub/tubes/chap12.htm
Sorry for the digression. I love this kind of thing.
Re # 19 dhogaza (and responses)
Once someone invokes Intelligent Design to explain the complexity and diversity of life on earth, all scientific principles go out the window – he/she is no longer constrained by natural laws or empirical knowledge. So, the “source of these internal forcings..[is] somehow un-knowable” (# 15 Arthur Smith)becomes an acceptable explanation.
Re: # 16 wmanny: If Spencer is indeed a member of the rock band, EcoFreako (# 21 bigcitylib), it is quite clear who is politicizing the issue of global warming (Hint: It is not Raypierre or anyone else at RC).
Badly done, RayPierre, on the censorship, and once again I get to demonstrate to my AGW colleagues, who led me to your site to begin with, exactly how tolerant you are of dissent. You are evangelicals all, at this place, and I will miss some of it, but there are clearly more useful places to go to seek genuine disinterest, debate and actual conflict of ideas. I have learned what RC’s true colors are, and it did not take as long as I thought it would. Sending a couple of students out to UChicago next fall, by the way, who will be sure to check you out. My son almost went there and arrived instead, coincidentally, at Bowdoin.
[Response: Thank you for your comments. They are most appreciated. Your son should make sure to touch base with Mark Battle, at Bowdoin, from whom he will learn much. Any of your students who reach U. of Chicago, will be warmly welcomed in any of my climate classes, or in Dave Archer’s introductory global warming class — which has just hit an enrollment of about 260, making it probably the biggest class in physical sciences at our place. Lively discussion from people who have taken the trouble to inform themselves of the scientific issues is always welcome. –raypierre]
Thanks for the answers about the WV feedback. One of the objections I imagined myself, and subsequently read somewhere, is that if there is a positive feedback why isn’t there a runaway temperature — boiling away the oceans and making the Earth become like Venus ? Since this didn’t happen in 4B years, a positive feedback is absurd, so the reasoning goes.
But I think the answer is: The main driving term for warming the Earth is the Sun, whose radiation output has varied randomly over long time periods (geological time) — sometimes going up and sometimes down. Other influences, e.g. volcanoes, orbital variations, etc, are also random over the long-haul, though even before humans, living systems presumably have changed the atomosphere (another topic entirely). It would seem, therefore, that the positive feedback does no harm if the driving term is random, but if the driving term (man-made CO2) is monotonically increasing in time, we can have trouble ahead.
Is this correct reasoning ?
A colleague of mine offered a dark view of feedbacks: humans, the present driving term, would possiblly die off in mass numbers due to rapid climate change and an economic inability to adjust, thus stopping the source of extra carbon and providing a negative feedback. A bit of black humor for you.
[Response: It’s important to recognize that a positive feedback does not in general lead to a runaway. It can act as an amplifier, causing the system to equilibrate at a stable temperature value that is warmer than what you would get without the feedback. This is the situation with Earth. The Venus runaway case is a more extreme version of water vapor feedback, in which the feedback is so strong that you don’t equilibrate until the whole ocean is evaporated into the atmosphere. In the present Earth situation, for every 1 degree of warming you get from CO2 directly, you get another 1 degree of warming that comes from the extra water vapor in the atmosphere at the TOTAL new warming — i.e. two degrees. The Sun has gotten gradually more luminous over time — by about 30% over 4 billion years, but its shorter term fluctuation are comparatively minor. Changes in greenhouse gas content of the atmosphere are believed to be the main drivers of climate over geological time scales. But that’s beside the point. Water vapor feedback amplifies any radiative forcing, whether solar brightness change or CO2. It’s not any difference between CO2 and the Sun that makes the difference in water vapor feedback. It’s that the Earth is in a state where a new (amplified) equilibrium is reached, not in a runaway state. –raypierre]
So, are we ever going to get a formal peer reviewed paper debunking
1. Douglass 2007
2. Spencer 2007
3. Spencer 2008
?
Skeptics seem to thrive on any sort of doubt or ambiguity.
Without a formal paper, it’s rather hard to kill it once and for all.
#60 R. Michaels
For mathematical visualization, suppose that a 1 degree rise in temperature led to some feedback f. Suppose this leads to f*f which leads to f*f*f and so on…so that deltaT = 1 + f + f^2 + f^3 + f^4…
if your feedback factor is less than 1 but greater than 0 (so that the feedback change is less than the original one, but positive) then eventually that series will converge to a stable system, but at a higher temperature. In the case of Venus, the planet passed a limit at which the incoming solar radiation exceeded the possible outgoing radiation (being just that much closer probably made the difference), but since the OLR goes up like the fourth power of the temperature it’s not easy to do…and it won’t on Earth until the sun gets much brighter.
I’m not sure if others would agree, but I would say that changes in greenhouse levels have been a more important cause for *changes in* climate over geologic time, than changes in the sun. In fact if you paint a broad brush picture of 4.6 billion years you are going from warmer to colder, no ice to ice, high greenhouse levels to low greenhouse levels, and a dim sun to a brighter sun. What’s more, just about every major climate change (or extinction) like the Cretaceous or Paleocene-Eocene or snowball earth in some way involves changing greenhouse levels.
#61
1) RC already did one
2) I see an MJO, not a “less positive feedback.”
3) Not there yet…I’ll get back to you
Actually…sorry, there isn’t a formal peer reviewed response to Douglass (as far as I know). I guess it would be good to see one, but it probably won’t be necessary.
Cheers
Walter Manny #59, I think you misunderstand the purpose of this site. Realclimate is a place where people can come and learn about climate science from the scientists who actually do it. Genuine scientific debate takes place within the pages of peer-reviewed scientific journals and at scientific conferences. The fact that the few genuine skeptics have nothing to say in those venues–and that on those rare occasions when they do publish, their ideas lead nowhere–demonstrates the infertility of denialism of anthropogenic causation. That the most virulent attacks of Spencer and other denialists come in nonscientific publications demonstrates that they are not based on science.
So if you ever develop an interest in actually learning the science, this site will be here as a resource for you. Indeed, belief in the science is not a prerequisite–merely a desire for ones opposition to be more informed. Until that time, there are plenty of places where one can pontificate in impotence.
Lee Grable writes:
Well, for thermal energy, the surface temperature is a good indicator! But if you want you can figure the amount of energy in the biosphere, atmosphere or ocean. Subdivide them properly — for instance, the atmosphere and ocean are different temperatures at different levels and in different locations — then multiply the mass by the specific heat and the temperature to find the thermal energy content in joules.
I’ll demonstrate with a very crude example. The atmosphere has a mass of about 5.136 x 1018 kilograms. The specific heat of moist air is around 1,010 Joules per Kelvin per kilogram. If the mean temperature of the atmosphere, then, is 255 K, then the total heat content of the atmosphere is 1.32 x 1024 Joules.
In my may years of model making of stellar atmospheres we use to say “given 8 free parameters we could fit the New York Skyline”. This is a very nice analysis of what can only be viewed as a deliberate deception.
Good post. Thank you for showing us your talents. You seem to be very good at cooking!!
[Response: Thanks. By the way, though I don’t entirely go along with the way Bryan S. has posed the issue of deep ocean heat burial, I do think he has raised a point worth further discussion, and I wouldn’t be unhappy to see the discussion turn in that direction. There isn’t any really good way of representing all the time scales you need within a single-layer formulation, and given the nature of ocean circulations it’s not clear how far you could go even with a two-layer formulation. The problem of shoehorning everything into a single response time was one of the things that led Steve Schwartz astray in his attempt to estimate climate sensitivity from observed temperature variations. Still, we needn’t restrict our discussion here to Spencer’s one-layer formulation. The question of how the actual mechanism of deep ocean heat burial affects decadal to centennial variability is an interesting one, that certainly merits further discussion. –raypierre]
Ray – In your response in #52, you say, “Clouds are a different matter. While there’s no credible evidence for a significant stabilizing cloud feedback, one can’t easily rule that out on basic physical grounds.”
However, doesn’t the same paleoclimate evidence that you noted in regards to the water vapor feedback also suggest that there can’t be a significantly-stabilizing cloud feedback either (or, at least that at the end of the day the net feedbacks have to still be positive)…Or is there something that I am missing here?
“Now, if you meant the other red curve, in the graph below, that is not from data at all. That is what you would get from Roy’s combination of the PDO and SO indices, using his scaling factor, if you don’t hide the amplitude by taking a five-year running mean.”
Ray, yes, I meant the “other” red curve that was output from Roy’s model. My question is whether you are comparing apples and apples with Wielecki’s “net” curve, or rather is your output (based on Roy’s assumptions) in fact the “total” TOA annual radiative flux density (range for both SW in and LW out)? It is not clear from the labeling what this graph actually represents. If your graph is in fact the latter, it would not be so clear that it is extremely jacked up compared to satellite observations.
I will have more to say on the ocean mixing when I have more time to formulate coherent thoughts.
[Response: The red curve in the graph labeled top-of-atmosphere anomaly — that’s the second graph, the one with amplitudes up to around 10 W/m**2 — is what you get from applying Roy’s scaling factor to Roy’s PDOI/SOI index. It is what is used to drive the mixed-layer model, and since it is net top-of-atmosphere flux that is the primary driver at the time scales of interest this should be compared to the green curve labeled NET in Wielecki’s data. I can see now I may have confused you by the choice of color for the lines — it would have been better if I made the curve in the scaled radiative forcing graph green. I hope that helps to clarify things, and I’ll look forward to your thoughts on ocean mixing. –raypierre]
I wonder if one can experimentally simulate CO2-driven warming ?
A modest proposal :
Suppose we took a remote patch of land and walled off a large section. The wall would need to be impervious to gas, a decent thermal insulator, and very lightweight material. The wall would need to extend from the ground to space. The area projected to the ground would need to be big enough to get a reasonable simulation of the atmosphere with its weather systems. Perhaps in northern Canada ?
Into this volume one would slowly inject up to 1000 ppm CO2 over a two year period and see what happens; the CO2 could be pumped from the rest of the atmosphere so that when the wall is dismantled it just diffuses back and causes no harm. Constructing and supporting the wall would be difficult — perhaps use numerous helium balloons to hold it up ?
Re: response to 67
I didn’t understand why Spencer resorted to finite difference simulations of a linear equation which he could have just solved exactly. Similarly if you’re sticking with linear models why not replace the finite number of layers with a continuum diffusive term in the depth? It wouldn’t require any more parameters and you could solve it exactly but I doubt seriously it would shed much light on heat burial. I don’t know the physics very well, but it seems to me that heat must get carried to the ocean bottom in downwellings and upwellings of cold water which probably occur preferentially in specific locations?
Spencer posted a rebuttal to this rebuttal:
http://climatesci.org/2008/05/22/a-response-to-ray-pierrehumbert%e2%80%99s-real-climate-post-of-may-21-2008-by-roy-spencer/
The best part is here:
“And besides, the SOI/PDO example took me 1 hour on a weekend with a very simple single idea, internet access, and an Excel spreadsheet.”
Along with:
“In fact, both Forster and Held had to construct their own simple models of the effect to understand what I was talking about so that they could convince themselves. Now, I am not a modeler – I’m more of an observationalist. Why did it take someone like me to point this out before anyone else in the modeling community discovered it? I’m not funded to do this stuff – they are.”
So this guy has the same credentials that I do? I was playing around with fitting ENSO data to the NASA climate data a couple of weekends ago and playing around with smoothing and scaling.
Should I submit my results to J. Climate?
“The IPCC, among others, nailed that, and nobody has demonstrated that natural variability can do the trick.”
You can certainly bullshit with the best of them, I’ll give you that… Since your whole website is directed at ‘true believers’ and generally non-technical people, how about a straightforward and easy to understand article that unambiguously proves the above sentence (that you repeat like a mantra), yet never seem to provide comprehensible evidence for? if it’s so obviously true, this shouldn’t be too hard to do. While I find some of the ‘denier’ arguments dumb or disingenuous at best, what you dish up on this web site is hardly reassuring either.
[Response: Why don’t you save us all some time and inform yourself before spouting off. It really isn’t that difficult in this case. All you needed to do was go to our “Highlights” sidebar and select “The IPCC Fourth Assessment Report” for a summary of that report, and in particular, sourcing for the conclusion that human influences on climate are ‘very likely’ (> 90% chance) already detectable in observational record, which is what Ray was simply stating in less technical parlance. On a more general note, if you are willing to inform yourself adequately enough to contribute meaningfully and constructively to the discourse on this site, you are welcome to do so. However, uniformed and ill-mannered blather such as you have provided us with this comment is not welcome here from either you or any other similarly minded would-be participants. -mike]
I second the request for more detailed discussion of oceanic mixing. How exactly are the oceans treated in an AOGCM ? are the currents, upwellings, deepwater formation zones put in by hand ? Is there any treatment of coupling to ice sheets ?
Even if this is not the right venue, I would greatly appreciate some references.
#71 Will
I recommend my post here:
http://chriscolose.wordpress.com/2007/12/18/the-scientific-basis-for-anthropogenic-climate-change/
and maybe
http://chriscolose.wordpress.com/2008/02/13/just-a-few-more-molecules/
Realclimates “CO2 problem in 6 easy steps” is also good. There is a wide variety of evidence from straight forward physics, the paleoclimatic record, etc tha tsupports man’s influence on climate today. Right now we have satellites showing the sun not changing over the long term, cosmic rays aren’t changing, heat is going in the ocean not going out, the stratosphere cooling, among other things that allow attribution now with high confidence.
I’ll second sidd, and take up Ray’s offer in #67.
It’s easy enough to visualise how GCMs handle the atmosphere. They generate realistic “weather” (albeit at a coarse scale) and project how that changes as the atmospheric forcings evolve. The numerical representation of the atmosphere is pretty sophisticated – we’ve been doing it for 50+ years – but what’s the equivalent state of the ocean models? What sort of layering and grid structure is used in the best models, and do they generate realistic currents, upwelling and downwelling, and how good is the atmospheric coupling? Modelling heat transport in the oceans is obviously crucial to both the general question of future climate states, but also to the shorter term regional forecasting that is the current goal of much study (and a recent post here). A post on the state of the ocean models would be enlightening…
Will Nitschke asks “Since your whole website is directed at ‘true believers’ and generally non-technical people, how about a straightforward and easy to understand article that unambiguously proves the above sentence (that you repeat like a mantra), yet never seem to provide comprehensible evidence for?”
Actually, Will, I work as a physicist and many other readers who comment regularly are technical as well. We appreciate the opportunity to learn about this important issue when we would not have time to read every technical paper AND keep up with our own technical field as well. How about you, Will? Are you serious about learning?
Actually, technical folks are pretty convinced by the evidence. There is currently not a single technical society that has looked at the evidence and taken a position running against the consensus position that humans are behind the current warming epoch. The few contrarian manuscripts that are published in peer-reviewed journals are met with silence and go on to die quiet deaths as they provide no path to progress. So, really, there’s not much argument in technical circles.
Re 70. I find it interesting that Pielke has posted Spencer’s response this post, but at the end it says, “Sorry, the comment form is closed at this time.” How very convenient.
I was once under the illusion that Pielke was actually trying to do something useful, however bumbling his efforts. No longer.
#71
“While I find some of the ‘denier’ arguments dumb or disingenuous at best, what you dish up on this web site is hardly reassuring either.”
As a thinly science-educated layman myself, I have spent a couple of years struggling to judge the credibility of either side of this ‘debate.’
In that time, I have never caught RealClimate in a lie. The same cannot be said for the most of the leading denier sources, who do not scruple in the slightest to ignore the truth in the cause of making a talking point.
The fact that the aforementioned deniers must always, at last, resort to conspiracy theories to explain why overwhelming scientific research is against them, is the slam dunk that says “game over,” to me.
#7 “The IPCC, among others, nailed that, and nobody has demonstrated that natural variability can do the trick.”
Will, please check out figure 2d in this paper:
http://www.cgd.ucar.edu/ccr/publications/meehl_additivity.pdf
While natural forcings alone can pretty well explain observations until about the middle of the twentieth century, anthropogenic forcings, along with natural variation, are needed to account for the observed warming of the past 3or 4 decades. This is what’s called doing science, not bulls–t.
#52, #68 clouds: the paleoclimate argument is strongest for me. If you add more energy to the system, whether by more CO2 or by an orbital change, or whatever other means, how do the clouds know the difference? If they were a magic stabilizing mechanism why didn’t they stop warming in previous interglacials?
On “Spencer’s rebuttal”
Spencer writes: //”It matters a great deal whether radiative fluctuations are the result of feedback on surface temperatureure, versus the myriad other variables that control cloudiness.”//
This just goes back to the question on what this internal radiative forcing (I’ll say IRF) hypothesis means. Does Spencer think that the ocean-atmosphere system has just changed by itself over the last few decades, with little to no external perturbation, leaving no evidence behind? All IRF is describing is the internal radiative changes from interannual variability like ENSO, but this has negligible impact on the global mean over climatological timescales, and the associated “fingerprints” and ciculations patterns are very different from a CO2-induced warming world.
Spencer writes: //”And if daily random cloud variations can do this, what might weekly, monthly, or yearly non-feedback fluctuations do? Any cloud changes resulting from fluctuations in stability, wind shear, precipitation efficiency, etc. accompanying El Niño/La Niña, the Pacific Decadal Oscillation, or any other mode of internal variability will ALWAYS look like positive feedback – even if there is no feedback present. “//
If there is an IRF (that can act like external forcings over decades) in the climate system during the last century, the signal is very weak, so we have to look really carefully to see it, and we need to explain why it just happens to “look like” CO2 variations (strat cooling, night time temps increasing faster than day temps, etc) and doesn’t look like a forced lower albedo or circualtion anomalies accompanying internal variation. Because any signal appears very small compared to the muted natural variability of the climate over the most recent millennia, the idea seems quite far-fetched that any influence of this possible-but-unproven natural forcing would suddenly become so huge as to swamp out the natural variability that has obscured it in the past and the strong changes expected from human influence. Scientifically, Spencer’s idea would be interesting if he could extend IRF outside of “weather” and to “Climate forcing”; it points towards “new physics”, and that is always good. But for prediction, I would not rely on it. And because we do not know how to account for it (or quantify it), we do not neven know the sign (in what direction it would be going), or where we are headed. What’s more, is that the IRF hypothesis cannot simply “cancel out” what we know about greenhouse gases and feedbacks. That is, we know that adding a greenhouse molecule heats up the planet because it retards the heat loss efficiency of the planet, we know water vapor gives a positive feedback, we know declining ice gives a positive feedback, etc. and that will happen even if you throw another (I) term into the mix.
Let’s use Spencer’s IRF hypothesis on ice-albedo instead of clouds. Spencer would argue that natural ice decline (possibly from a positive AO or something) is resulting in a lower albedo, and thus a global mean effect that “looks like” a feedback. In turn, higher polar temperatures might affect cloud cover permanently, which might further effect SW or LW fluxes. Assuming this idea carried any explanatory power, you couldn’t just replace CO2 with this new “ice-albedo forcing” hypothesis, you’d only need to add to it, and any possible internal forcing would simply be superimposed on the (much larger) anthropogenic signal. When dealing with a multitude of factors that can change climate, you have to take the sum of them all, not play the “Either-or” game.
Spencer writes: //”And besides, the SOI/PDO example took me 1 hour on a weekend with a very simple single idea, internet access, and an Excel spreadsheet. In stark contrast, the IPCC work represents many years and hundreds of millions of dollars of effort to connect the few degrees of freedom contained in the last 100 years of global temperature variations to an anthropogenic cause for those low-frequency signals. What might we have learned if we put that kind of money and brainpower into looking for potential natural non-feedback sources of radiative variability?”//
This is pure nonsense. The IPCC does not represent an effort to connect dots between global mean temp. and CO2, nor does the IPCC do original research. The IPCC collects, interprets, and summarizes the standing literature and knowledge on the subject. It’s hard to include something that has no peer-reviewed backing to it (IRF) and much easier to talk about something with a mountain of literature to support it (AGW). Interestingly, Spencer does not address much regarding the “cooking up” of the graph.
//”Well, contrary to Ray’s claim, we corrected those errors after they were demonstrated.”//
But that didn’t stop Fred Singer from saying that the AGW hypothesis is falsified, right after 5 minutes of Lindzen, Christy, and Pat Michaels talking about the surface/atmosphere temperature “discrepanacy” from satellites and weather balloons in the Swindle Video, eh? It still doesn’t stop Bob Carter from saying that if you remove the effects of El Nino, there is no warming since 1979. More examples?
//”…But the claim that an anthropogenic source for the warming has been demonstrated to a high level of confidence can not be supported…simply because so little work on potential natural causes has been done.”//
While ignoring a centuries plus worth of physics… Or it might be that the natural variations being too small to account for modern warming is just too inconvenient? The question I pose for Roy Spencer, is what kind of evidence would demosntrate with high confidence that there is an anthropogenic cause for modern warming? MEanwhile, while the noise on certain blogs is going up more and more, the paradigm of AGW has repeatedly proven to be successfully predictive as well as explanatory with very high confidence; thus far, no one has been able to provide a natural mechanism to account for modern warming, nor any substantial reason to doubt the IPCC range for climate sensitivity.
Thanks for that WSJ note at the end of the post. I tried to find the original article and like clockwork, junkscience.com still has it.
http://www.junkscience.com/news/robinson.htm
This is an interesting quote:
“During the past 20 years, atmospheric temperatures have actually tended to go down”
Sounds familiar
“, as shown in the second chart, based on VERY RELIABLE satellite data, which have been confirmed by measurements from weather balloons.”
Notice that data is only “very reliable” to contrarians when it tells them what they want to hear. And of course we now know it wasn’t reliable in the least. It should also go without saying that the WSJ isn’t at all reliable at least with regards to climate science.
A book review article by Freeman Dyson “The Question of Global Warming ” in the NY Review of Books is now online at: http://www.nybooks.com/articles/21494
A Question of Balance: Weighing the Options on Global Warming Policies
by William Nordhaus
&
Global Warming: Looking Beyond Kyoto
edited
by Ernesto Zedillo
Article well written, simple, and he offers a nice foundations. One point of contention:
“…the average lifetime of a molecule of carbon dioxide in the atmosphere, before it is captured by vegetation and afterward released, is about twelve years”
Is 12 years commonly accepted?
[Response: Using his definition (reservoir/(land+ocean flux) ) it’s more like 5 years. However, that isn’t the same as the perturbation timescale (how long a pulse of emissions keeps the CO2 level high). As described by David and colleagues, that is a very complex function of ocean chemistry and transport, and is usually reckoned in the hundreds of years. Note that there isn’t just one number for this timescale. – gavin]
More news from the Arctic that’s no cause for alarm:
#71 It is pretty apparent that most people on here are technical people. Ray is a physicist. I am a physicist. We both appreciate this site as a way to stay informed on an important issue without having to try to read all the technical papers in a field other than our own. Many many others are very clearly technical people. What do you do? I entered your name into google scholar to find out but came up empty.
People who are looking for discussions about layer and ocean heat issues:
OHC: latest numbers
Ocean Cooling. Not.
Look for comments by Josh Willis and Bryan S., and, of course, contributor responses.
When the paper, recently in the news, by Josh Willis is published, perhaps RC will have a new article. Anyway, that is what has kept me on the edge of my chair. Somewhere Brian M. Flynn posted an extensive recap. You might look for that.
RE 83:
Following cryosphere today is like watching a slow motion train wreck. Horrifying, but fascinating. This shows todays arctic ice coverage versus last year’s on this date. There is more open water this year, and to my eye, more partial coverage than last year. Open water showing west of Greenland, in Hudson’s bay, north of European Russia, north and south of Banks Island, north of Alaska.
Re #88
Quikscat too! Try watching this movie (up to yesterday) particularly the Beaufort sea and the long lead that’s opened up along the coast to Ellesmere Island.
http://ice-glaces.ec.gc.ca/App/WsvPageDsp.cfm?Lang=eng&lnid=43&ScndLvl=no&ID=11892
#88 Tim McDermott: Thanks for the link. It’s instructive to compare summer sea ice extent (e.g 31 August) for 1998, the year “global warming ended”, with the nearest equivalent time (2007).
See any difference?
Next trick: successively set up scenarios from comparison of 1998 with 1999 and successive years then use your browser’s forward and back buttons to make a slide show. Show this to anyone who wants to believe global warming ended in 1998.
Until he approaches science of some sort a lot more closely in this crusade of his, I’m going to call Spencer’s “internal radiative forcing” spontaneous atmospheric parameter value change.
Maybe it’s caused by large banks of subterranean fudge that we didn’t factor into our equations?
#23 Gary Plyler
To see what La Thuile was like in March 2008 you can try YouTube videos: try Snowboarding holiday La Thuile, Italy http://www.youtube.com/watch?v=1wrKz_QftSM or this one – shows what the hotel looks like (from the other side ie the front) about a week earlier: http://www.youtube.com/watch?v=gTr7S6q73qo
In the first week of March there was about 40cm on lower slopes and 1.5m on upper slopes – there was some snow fall in March as you’ll see from the videos
(http://www.skiclub.co.uk/skiclub/reports/historical/report.asp) and the temperatures were forecast to be 0-4 deg C (http://www.snow-forecast.com/resorts/La-Thuile/hindcasts/2008-03-06/bot)
[Response: I’m not sure what your point is, but the meeting was March 2-8 and except for scattered melting patches of snow, the ground was mostly bare at the level of the town. I was there and walked on the mud myself. It was warm and the snow was melting everwhere at town-level, even in the shady parts of the valleys, though there was enough base that one could still ski on the slush. Behind the hotel where the lifts start, there was in icy-skiable crust, since they started with base and do heavy track maintainence so that people can get to the lifts. There was only the faintest dusting of new snow during the week, except near the mountain top. i had a great time anyway. I’m not making any claim whatsoever regarding the attribution of this warm weather in early March, but I’m just responding to #28’s implication that I picked an archival photo to give a misleading subliminal impression of warmth. –raypierre]
Spencer has added a follow up to his rebuttal.
#73 Will Nitschke
I agree with Mike.
But you was a simple way to understand why “nobody has demonstrated that natural variability can do the trick.”
Here’s one for you. Lot’s of people say that there is no proof and it’s probably natural cycle, even though the evidence is well understood and not to difficult to understand, even for non scientists (that look hard enough). We won’t get into the problem with critical thinking and the educational system here.
Here’s a simple way to understand it. For millions of years the temperature has varied in natural cycles. In the well understood Milankovitch cycles the pattern of warming and cooling is referred to as the 100k Year cycle (for the past 1 million years).
Here is how it works, earth slips into an ice age (when further from the sun), then when it gets close to the sun again it warms up and comes out of the ice age (this happens pretty fast, in a few thousand years). Then, guess what… it goes back into an ice age (It never stays to long in the warm period though, some thousands of years or so).
Then another magical thing happens, it comes out of the ice age. And believe it or not, the next thing that happens is it goes back into an ice age. then out, then in, then out then in, then out… You get the picture? That is the natural cycle.
Well we came out of an ice age 15,000 years ago. Let’s see if you can guess what is supposed to happen next?
Choice A. We go back into and ice age, just like the natural cycle?
Choice B. We warm up even more, because something changed to alter the natural cycle?
It’s very simple to understand. According to the natural cycle, we were supposed to be going into an ice age and now we are heating up. From a geophysical/atmospheric point of view only one thing changed.
That is the of course the concentration of GHG’s in the system which increased the forcing level. Is that simple enough for you, or do you want me to draw you a picture?
And while you might think that a good thing (which is typically the next thing science deniers go to), do yourself a favor: Check the prices of tomatoes and lemons and other food items and ask yourself how long do you think you can afford the food price increases?
Many commodities went up 40 to 100% in the past year alone. The commodity prices are not a cycle in this case, they are a trend, based on warming and loss of crop lands; as well as demand for a still increasing world population.
That now mixed in with hedge fund market manipulation and biofuel development to answer that other little problem of increasing oil prices…
So ask yourself again, how much warming do you think the human socio-economic system can handle in a reasonable fashion?
Best,
John
And please read more of the real science and try to stay of the junk science, it’s bad for your health.
In this question as to what you can say to a denier or a skeptic the answer is frequently “nothing”.
I was on a discussion board with a completely different focus (American football) and somehow the topic of climate change came up. After giving what I thought were sound scientific reasons for climate change I got this answer:
“When you prove to me that man is causing climate change THEN I will give a s..t about science”
Re #93
“Spencer has added a follow up to his rebuttal.”
Of course like his rebuttal he does where comments aren’t allowed!
JPR, one remark: in my recollection of another excellent piece of work by Tamino, it’s more the geographical distribution of solar energy on the Earth than the distance to the Sun that induces glaciation/deglaciation in the Milankovitch cycles. The total amount of energy received does not really change. See these posts:
http://tamino.wordpress.com/2007/11/19/wobbles-part-1/
http://tamino.wordpress.com/2007/12/02/wobbles-part-2/
It’s interesting that we’re already starting to see alarming (I know some don’t like that word, too bad for them) signs about the state of Arctic ice although we’re still in May (!).
Undoubtedly, there will be some to argue that it’s natural variability, and that whatever ice is lost will be back next year. Whatever.
Just like there will be some to argue that we should continue to feed the entire economy on oil even as it edges ever closer to $200/Bl.
Meanwhile, Spencer and others carry on with their “stuff” (the word I’d really want to say would probably be edited). This is getting ridiculous.
#93 JCH,
Thanks for that link.
I got there just in time to see Dr Spencer’s head disappearing below the turf.
Looks like he’s still digging. ;)
Factoring in a millenial/centennial damping to address a decadal observation, oh dear. And apparently it’s OK to pick arbitrary offsets to make the graph more persuasive because that offset is irrelevant to the key issue. Very revealing.
By his replies Dr Spencer has merely delivered the coup-de-gras to his own graph.
#90 Philip Machanick,
Sorry to be pedantic but…
Even if we had good reason to see 1998 as the peak, the subsequent events in the Arctic would still have happened. I’d avoid using argument like that based on such secondary effects. It can end up a bit like denying arson because the building is still burning yet your matches are in your pocket.
“That now mixed in with hedge fund market manipulation and biofuel development to answer that other little problem of increasing oil prices… ” – John P. Reisman at 94
Recently a large brokerage firm invited assault by rotten tomatoes for suggesting we owe a debt of gratitude to hedge funds for accelerating the rationalizing of the price of oil, which I have to agree was exceedingly low for more than two decades. The low oil price led society to make all sorts of totally irrational infrastructure decisions that will have to be undone, and at considerable expense.
It was interesting to hear Robert Crandall, the former CEO of American Airlines, lay out an example of the irrational decision making caused by suppressed oil prices. He stated that nobody should be flying from New York to Washington DC; according to him that trip should be made by either bus or train. The reason most fly – cheap jet fuel rationalized airport construction, airline expansion, airline startups, etc.
Had we continued paying a rational price for oil from the late 1970s until now, that is exactly how most would be making that trip: by bus or by train.
Please no more discussion on ID. There are plenty of other places in the blogosphere where that is allowed (nay, encouraged!). – gavin