How to cook a graph in three easy lessons
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.
21 mai 2008 at 10:42 PM
Of course there is the famous:
All Theories Proven with One Graph
http://www.jir.com/graph_contest/index.html#OneGraph
21 mai 2008 at 10:53 PM
Raypierre:
What do you suppose motivates someone, a scientist, nontheless, do cook his data this way and make such a concerted effort to mislead the public?
[Response: That’s a question for psychologists. I wish I knew the answer. I doubt that he, or Dick Lindzen for that matter, are in it for the money, so that takes out the easiest of motives. I think it’s probably a matter of ideological blinders. The perceived implications of global warming being a real problem are so dissonant with some other value system that it imposes some kind of filter on the interpretation of objective reality. Anything I say would be just guessing, though. Fortunately, this problem doesn’t seem to plague too many scientists. –raypierre]
22 mai 2008 at 12:02 AM
Raypierre, Thanks for this. Very difficult for the layman to spot such chicanery.
I wondered about the graphs in the merde du jour “Science Has Spoken: Global Warming Is a Myth”, by Robinson & Robinson 1997, both from the “Oregon Instutute of Science & Medicine”. The source given was the ExxonMobil funded Mashall Institute. So now we know!
According to exxonsecrets.org, Spencer is on the payroll of numerous other ExxonMobil funded think-tanks.
Google Roy Spencer site:exxonsecrets.org - lots of hits!
For more from the “Oregon Instutute of Science & Medicine”
http://www.realclimate.org/index.php/archives/2007/10/oregon-institute-of-science-and-malarkey/
22 mai 2008 at 12:12 AM
//”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?”//
I certainly read the “internal radiative forcing” idea as something like this (actually I didn’t see any other way to interpret it). For the most part, I’ve not seen much evidence to suggest that internal variations alone can bring the climate to a new state on decadal timescales, even if the internal fluctuations do not completely average out over decades (e.g.,, the PDO being in a positive phase more than a negative phase during the timescale of consideration). What I was reminded of though is something along the lines of the hypothesis of a very weak signal/stochastic-resonance idea, where “noise” and a very weak “signal” could combine (similar to some of the D-O hypotheses out there). Perhaps Spencer could try to relate secular cloud changes as internal variations superimposed on a rising trend (he at least seems to admit that the 2x CO2 non-feedback value is 1.2 C).
Though, there is yearly variability all the time, and the ocean and atmosphere are constantly exchanging heat back and forth on time scales characteristic of the mixed layer, which can be more than a year, and that should change radiative fluxes on monthly to yearly timescales. But you’re precisely right… that is weather. Why should the late 20th century be any different from any other time, and where are these decadal weather forcings in the paleo record?
On the possibility of a changing cloud cover “forcing” global warming in recent times (assuming we can just ignore the CO2 physics and current literature on feedbacks, since I don’t see a contradiction between an internal radiative forcing and positive feedbacks), one would have to explain a few things, like why the diurnal temperature gradient would decrease with a planet being warmed by decreased albedo…why the stratosphere should cool…why winters should warm faster than summers…essentially the same questions that come with the cosmic ray hypothesis.
The key questions are whether internal fluctuations will not actually average out to zero and cause a positive rise in temperatures on long time scales, and is this forcing sufficient to overcome that of well-mixed greenhouse gases. I say the answer to both is no.
22 mai 2008 at 1:43 AM
The people who tell us that computer models are no good because, despite being based on physics, there are gaps, want us to believe that this sort of pure data massaging is somehow superior. I was watching a YouTube of Bob Carter’s recently and he was banging on the claim that computer models are useless because you have to work around gaps in knowledge. His superior solution? Extrapolate from past data which doesn’t include any anthropogenic effects.
The fundamental flaw in almost all the denial arguments I’ve seen is that they start from the premise that global warming isn’t happening therefore the best model is the past.
Sadly there seems to be no limit to how pathetic the argument can be, and some people still consider it plausible.
I like the “inactivists” tag.
22 mai 2008 at 2:47 AM
Spencer is doing what I, as a naive teenager, did with Bode’s Law — curve-fitting by adjusting an arbitrary number of parameters. I got some wonderful fits when I had six or twelve arbitrary constants to play with (for the nine-planet system we had in the ’70s). Both Spencer’s work and mine depend on the statistical fallacy called “the enumeration of favorable circumstances.”
22 mai 2008 at 3:58 AM
Thanks for the thorough analysis. This article has already come up in a few discussions with some who remain skeptics. I now can argue against Spencer’s results. Thanks to Julia too.
22 mai 2008 at 4:13 AM
raypierre
Are you sure with your only 50m mixed layer?
I think that if you apply this little depth, with RF evolution in the last century, you find a very weak climate sensitivity.
To explain the actual temperature anomaly, with a very (too?) simple “model” and with a climate sensitivity of 0.75°C.m2/W, I need, at least, a global 200-300m mixed layer.
For the south hemisphere only it is far deeper.
[Response: No, I don’t think a 50m mixed layer by itself is an adequate description of relaxation. I wanted to stick with the same model Spencer used, and that meant sticking with a one-layer ocean model. The point is that if one is going to go that route, a one km mixed layer gives you far too much thermal inertia. –raypierre]
22 mai 2008 at 4:24 AM
raypierre
I add to my precedent post that, for me, the mixed layer is an “equivalent” mixed layer which includes the thermal exchange between the real mixed layer (which is delimited by the thermocline) and the deeper layers.
I think you agree that the 0-3000 m layer is heating (if we refer to Levitus for example)
22 mai 2008 at 5:12 AM
Roy Spencer is an interesting character to me. His peer-reviewed published track record seems reputable. But his non-peer reviewed statements seem to be full of [edit] distortions. See his 2007 testimony to congress for example.
http://oversight.house.gov/documents/20070320152338-19776.pdf
How does someone like this match up his professional and personal beliefs?
22 mai 2008 at 6:01 AM
Hmm. Methinks I understand the sudden appearance of Gerry Browning, Ferenc M. Miskolczi, et al. They are trying to trash the use of dynamical models using real physics so that the ad hoc approach described here seems to have equal credibility. What a brilliant approach to solving the problem of climate change: All they have to do is change the laws of physics!
22 mai 2008 at 6:35 AM
Nicely put, guys.
Re. graphs that ’show’ things, I particularly like the supposed correlation between global warming and piracy on the high seas:
http://www.scq.ubc.ca/piracy-as-a-preventor-of-tropical-cyclones/
Worth a look if you want to be more creative with your data …
22 mai 2008 at 6:53 AM
The EIB Network is not going to be happy with you guys.
22 mai 2008 at 7:44 AM
raypierre,
Thank you for taking the time to wade through this and attempting to replicate Spencer’s results. That kind of work won’t get you any grants, but nevertheless it’s crucially important for the health of the science!
And thank you for writing it all up in a clear, enlightening, and entertaining fashion.
22 mai 2008 at 8:30 AM
I’ve had some blog back-and-forth with Roy Spencer on this “internal forcing” business, though I wasn’t as clear on the problem with it as you are here. Anyway, my impression after reading some of his responses was that he’s making it deliberately vague as if the source of these internal forcings were somehow un-knowable; surely that’s not the stance of a normal scientist, is it? Wouldn’t you want to get to the bottom of some mysterious internal behavior of this sort? But instead the argument seems to be these are random, uncaused features of Earth’s climate…
On graphs that “show” things, I’ve seen a graph that showed a very close match through the decades between the Keeling curve of CO2 levels in the atmosphere, and the number of submissions to scientific journals (even the seasonal variations match up…). With just two free parameters (scale and offset) you can prove a lot of remarkable things! Who knew that scientific publication was actually the cause of global warming?
22 mai 2008 at 8:38 AM
Pierrehumbert unwittingly makes the point, I believe, that disagreement about what goes into the models (e.g. arguably unrealistic radiative forcing in Spencer’s) is precisely why there is no consensus on the subject of AGW, media repetition of that insistence notwithstanding.
All the books are cooked, because that’s what models are, [necessarily] cooked books with ever-improving inputs. As required by the scientific method, Pierrehumbert properly assumes the Spencer model is wrong until it can be verified. Why RC assumes the other, scarier models are right, following a faith-based assumption that the preferred models are correct until proven otherwise, is problematic. In twenty years time, when, for example, we might know enough about the variability of the Earth’s radiation budget, I think we can agree that we’ll chuckle to some extent at the relatively primitive and incomplete models we are using today.
The politicization of the issue, on both sides, makes it well-nigh impossible to get at the science for readers such as me, as desire outweighs reason so much of the time. I am left with little alternative than to distrust any and all models until more facts are in about this chaotic climate of ours.
[Response: No, the post makes the point that you can’t just make up stuff to put in models to make them come out the way you want. There are uncertainties in parts of the general circulation models used to forecast future climate, but thousands of scientists have made meticulous efforts to make sure that the processes are based on observations of basic physics, laboratory measurements, and sound theoretical calculations. The work that has gone into the representation of ocean circulations and heat burial is a case in point. This isn’t perfect, to be sure, but it is constrained by things like ocean chemical tracer analyses. It’s the sort of thing that allows us to go beyond arbitrary one-layer mixed layer models. –raypierre]
22 mai 2008 at 8:39 AM
Raypierre– Ditto what #14 Anthony Kendall says, this is a substantial piece of work that doesn’t add to your “publication” record, but highly useful and illuminating. You are owed thanks by every rational person concerned by the misinformation that circulates. A recent Pew Center poll shows that a DEcreasing fraction of conservative Republicans think AGW is a problem! Thanks I suppose to guys like Roy Spencer.
But, um, please do give full labels for the graphs in lesson one, what’s LW, SW and NET ?
[Response: Sorry, I pulled that last graph out of the Science article without including the caption. LW is the fluctuation in the longwave (infrared) component of the top-of-atmosphere energy budget. SW is the shortwave (mostly cloud reflection) component. The sum is NET, which is the net fluctuation in the top-of-atmosphere component. The trends in LW and SW are larger than the trend in NET, but it should be noted that getting decadal trends out of satellite data of this sort is difficult. I’m sure this paper isn’t the last word on the subject, but it at least gives us some idea of the actual magnitude of interannual fluctuations of the energy budget. –raypierre]
22 mai 2008 at 8:51 AM
RayPierre: Let me add my thanks for your work in taking this apart. I have read a number of his earlier papers and I would go as far as to call his initial work “ground breaking”. Sadly he appears to have strayed more into politics than science in recent years.
Not too long ago he published an opinion piece that the current rise in CO2 is not due to anthropogenic sources but ocean temperatures are the drivers. He threw in a lot of phrases saying “This is probably the most provocative hypothesis I have ever (and will ever) advance:“, he knew most did not accept it, etc. etc.
Of course now when people quote it, they seem to lose the idea that it is a “provocative hypothesis” and accept it as carved in stone.
John
22 mai 2008 at 9:50 AM
He’s also a creationist, of the intelligent design subspecies. It seems quite safe to assume that his conservative christian faith drives his personal opinion about science, when science conflicts with that faith. “Lying about science for Jesus” seems to be common among conservative fundamentalists, unfortunately. Spencer’s hashing of the data regarding climate change is no different than the misrepresentations of biology and evolution that comes from the creationist/intelligent design crowd. His buying into the latter is maybe easier to understand because he’s not an evolutionary biologist so perhaps can be forgiven for being ignorant of what the science really says. But climate science? It’s his field. There’s no excuse.
22 mai 2008 at 9:52 AM
RayPIerre’s piece not only puts a wooden stake through the heart of Spencer’s argument, but he’s funny, too! If he’s this humorous in English, what’s he like in french?
22 mai 2008 at 9:53 AM
Very useful post.
It would be interesting to do a compare/contrast between what goes into Roy’s blog vs. what he gets through peer review. There was an earlier version of the paper with Brasswell floating around when it had been (if I remember correctly) accepted conditional upon certain changes. Even in that state I believe his formulation was something like “provides weak/marginal support to the IRIS conjecture”. Very mild stuff, in other words.
All else said, however, his rock band is mildly humorous:
http://bigcitylib.blogspot.com/2007/12/hard-rockin-creationist-solos-for.html#links
22 mai 2008 at 9:58 AM
I am clealy not spending enough time in the kitchen in preparing graphs for publication. Excellent work picking through the manufacturing process of a graph, not easy to do. As to motivation, look no further then the attention that is recieved.
22 mai 2008 at 10:50 AM
Raypierre:
I still have not recieved an answer for my question about your “Venus Unveiled” article. In early March of this year you attended a conference at the little ski resort of La Thuile in the Val D’Aosta, the Italian Alps. Your article included a picture of a resort with little snow on the ground. Was that picture taken by you that week or was it some summer picture included in your article for subliminal purposes?
[Response: I wasn’t even thinking of subliminal purposes when I put up that picture; I put it up to give some sense of the natural beauty of the setting. But, in fact I’m glad you asked. That picture was taken during the meeting by Darren Williams, and yes, it was hot and there was hardly any snow on the ground. I managed to stick on a lot of klister and find enough melting snow in the valleys to cross-country ski on, but yes it was hot and the spring skiing was pretty rotten. –raypierre]
22 mai 2008 at 11:19 AM
What an awesome post!
And thank you for that terrific final paragraph on how they botched the satellite data for so long, just coincidentally making a bunch of mistakes that pushed their mis-analysis all in the same, wrong direction.
Anyway, you inspired me:
http://climateprogress.org/2008/05/22/should-you-believe-anything-john-christy-or-roy-spencer-say/
22 mai 2008 at 11:33 AM
Re #16. Walter Manny unwittingly makes the point that he doesn’t understand the difference between dynamical and statistical modeling, while simultaneously showing he doesn’t understand how models are validated. Dynamical models include the physics as best it can be determined–so their agreement with observations is their validation. Statistical models look at past performance and assume the future will perform similarly–the fallacy of which can be seen in all those AAA rated mort-gage-backed securities that are now being recycled for toilet paper.
22 mai 2008 at 11:54 AM
I’ve learned a lot from realclimate, I thank you all for your efforts here.
Now the inevitable caveat. I’ve been around a while, and in that time I’ve followed all manner of scientific and other debate, many of which have eventually been resolved. Here’s a statistical observation from those debates: the side employing a relatively higher personal focus in their attacks on the other side’s ideas is eventually proven wrong a higher percentage of the time.
I didn’t see anything personal in Spencer’s article, nor do I find it on Pielke’s site in general. But I do here, too often. You’re scientists, wage a war of facts and ideas, your readers will figure out for themselves who’s credible and why.
If I misunderstand the purpose of this site, if it’s just for the faithful to gather and reinforce themselves and have their jollies, please hang a big sign to that effect on your homepage. If you’re trying to educate and convince all we need are the facts, ma’am, just the facts.
22 mai 2008 at 12:17 PM
Let me add my thanks for you efforts! This is just what is needed
at this time since quotations from Spencer are being widely
circulated on discussion sites. I will be looking forward to
your review of his peer reviewed papers, particularly
“Cloud and radiation budget changes associated with tropical
intraseasonal oscillations,” published in GEOPHYSICAL RESEARCH
LETTERS in August, 2007.
22 mai 2008 at 12:29 PM
Ken Milne:
“the side employing a relatively higher personal focus in their attacks on the other side’s ideas”
The irony.
How about attacking the facts presented by Ray Pierre instead of attacking the person, as per your own advice? Thank you very much.
22 mai 2008 at 12:43 PM
Ken, I would agree with you if Ray had been dealing with honest errors by someone seriously trying to get at the truth. But an effort that is, in effect, a parody of science deserves to be parodied. I do not think Ray got personal about this at all. He simply pointed out the obvious dishonesty (or incompetence, take your choice) behind the methodology employed.
22 mai 2008 at 12:53 PM
Raypierre,
Thanks for an excellent post that was easy to follow, insightful, and very convincing. It’s very sad to see a scientist like Spencer seemingly blinded by his own biases or simply unwilling to accept his earlier errors (thus he needs to keep shifting the debate and somehow try to save face). All scientists make errors. The good ones accept it and move on to do other good work.
22 mai 2008 at 12:57 PM
I realize this is off topic for this particular thread, but it does relate to a bet, and therefore to previous ones. It would appear that the Govenor of Alaska is going to take the EPA to court,and challenge the ruling that polar bears are threatened. Since most of the justification for the EPA ruling is based on the predictions of AGW, it will be interesting to see how the court rules, if it indeed comes to trial and a verdict is reached. Anyone want to make any bets?
22 mai 2008 at 1:23 PM
Re Jim’s bet in 31, I’ll bet that if we have an ice-pack free arctic this summer, Alaska’s suit will fail.
22 mai 2008 at 1:43 PM
Given that the polar bear listing was a response to a suit the feds were in the process of losing badly, I’d say the Alaskan governor is just going to waste the taxpayers money.
22 mai 2008 at 2:05 PM
Since PDO’s gotten a lot of press coverage recently, I’d love to see a full post on it and its implication on changes on attribution of climate change.
Since this post is about Spencer, a recent op-ed of his is notable:
http://article.nationalreview.com/?q=NTUzNWUzYTA4ZTkwMTVhZmM3M2NkZDc5NDhmOTRkMzA=
Here’s what really bothers me about op-ed pieces like this. Spencer is making ridiculous arguments, yet he clearly is smart enough to know how fallacious they are and it doesn’t take a top expert to point them out. Examples:
- “Apparently, our addition of nine molecules of carbon dioxide to each 100,000 molecules of air over the last 150 years can now be blamed for anything and everything we choose.”
This is an attempt to fool the layperson into thinking the change to our atmosphere is insignificant.
- “The warming that allowed the Vikings to farm in Greenland 1,000 years ago was surely natural. But we are now told that warming in Greenland today is surely manmade. Glaciers retreating in western Canada have revealed evidence of previous forests, showing that warming and cooling cycles do indeed occur, even without SUVs. Yet the SUV is now the scapegoat for retreating glaciers.”
Last year my car didn’t start because of a bad battery. This morning it didn’t start. Even though the battery was tested to be fine and all signs point to a faulty starter, Spencer’s logic would have us believe it’s the battery again.
- “But McCain has made it clear that the science really does not matter anyway because, even if humans are not to blame for global warming, stopping carbon-dioxide emissions is the right thing to do. And if we had another choice for most of our energy needs, I might be willing to accept such a claim as harmless enough.”
McCain thinks science doesn’t matter? Quite the contrary in fact. And we do have other choices for our energy needs.
- “But carbon dioxide is necessary for life on Earth, and I have a difficult time calling something so fundamentally important a “pollutant.” ”
So is the sun, but we don’t really want any more of it.
- “So, here we are with bad science ready to support bad policy decisions that will lead to bad economic times ahead, and no presidential candidate who is willing to ask the hard questions. ”
“Bad economic times”. It’s ironic that those claiming mitigation efforts will cause economic ruin label the scientific community as “alarmist”.
Here’s what I dont’ get: There seems to be no shortage of loud political commentary from contrarians, as seen on various op-ed pages, yet when a scientist from the consensus community makes any suggestion of reducing emissions, an obvious implication from what the science says, it’s a big deal and they are labelled as activists or ideologues.
22 mai 2008 at 2:17 PM
RE: #19
Let’s keep the establishment of religion out of this discussion. […edit…]
[Response: Agreed with that. I deleted the rest of your comment because of the inflammatory accusations. But generally, I agree that one’s religious perspectives don’t have much bearing on attitude to climate change, since I have met plenty of devout from all religious who are concerned about care of creation. I do think, however, that skepticism about evolution is relevant information, from the standpoint of attitude towards scientific argument and ability to deny or distort evidence. But please, let’s not go any further into religion. –raypierre]
22 mai 2008 at 2:21 PM
Thanx for the deconstruction.
I have a question regarding the mixed ocean layer. I would be grateful for a reference showing the time it takes for the ocean to mix to different depths. The article indicates a mixing time of 100 yr for 1000 m; for 50 m i gather the mixing time is on the order of 1 yr ? what would an appropriate mixing time be for say, 300m and 3000m ?
I do understand that these mixing times vary depending upon locale, season, tide , topo, … but are there order of magnitude estimates somewhere ?
[Response: Actually, there are two separate issues floating around in your question. The first is: what is the response time for a given mixed layer depth. That one is easy: all other things being equal, it’s proportional to the mixed layer depth, and using Spencer’s sensitivity coefficient you get something on the order of 50 years for a 1000m mixed layer. The question of how long it actually takes an ocean to redistribute heat to a depth of, say, 1000 meters is more complicated, especially since the processes that mix heat down to those depths are not at all globally uniform. I don’t know how to give a simple few-line answer to that question, except to say that over a time scale of a hundred years, some heat does mix down to a depth of around 300m, which is why we have “committed warming” in the pipeline. In a sense, you have to wait for those deeper waters to finish warming before they stop removing energy from the upper ocean. –raypierre]
22 mai 2008 at 3:28 PM
I’m new here, but I have to ask, is there a way(there should be) to measure the total amount of heat energy in our biosphere? Seems to me that if that number were made public,and talked about, it would disspell a lot confusing talk from the skeptic side about ‘how cold it was in Nebraska last winter, and how that proves that man made global warming is a hoax’.
[Response: I don’t think you are asking the right question, and certainly an answer to that question would not do anything much to address the tendency of certain parties to extrapolate from one or two winters to a long term trend. Could you clarify your reasoning here? Then maybe I can be more enlightening. –raypierre]
22 mai 2008 at 3:37 PM
RayPierre:
This was my point. If my comment was understood to criticize Christianity or Christians in general, I apologize. The vast majority of Christians don’t reject science.
22 mai 2008 at 3:59 PM
Thanks Raypierre,
That was great (love the photo). I was thinking of other analogous illustrations for this phenomenon.
Since we are talking about cooking: The fact that much of prepared food is now sold to us with manufactured ingredients as opposed to real food.
They create all these interesting flavor enhancements to tantalize our pallets and trigger dopamine responses. But it’s not real food. Nowadays, I check labels to see if what I’m buying has any new and interesting created ingredients.
My wife thinks that the ads with the doctors smoking, saying “Look, I smoke” also applies here as well. Propaganda and disinformation is an art it seems.
When all is said and done, and the evidence is assimilated after it becomes tragically obvious, I wonder how any of these folks, (scientists cooking with manufactured ingredients) will feel about their contributions?
Best,
John
PS I did a point by point on John Coleman, mainly because I know a lot of people are claiming that because he started the weather channel he must know what he is talking about.
http://www.uscentrist.org/about/issues/environment/john_coleman
I think it relates here also since we are talking about cooking and the weather v. climate debate.
PPS There are some charts in his presentation that I could not find references to. If anyone knows their source so I can properly address them, would be appreciated if you drop me a note via the contact form on www.uscentrist.org (the ones about the solar/temp connections).
22 mai 2008 at 4:12 PM
Re; #36: Raypierre says:
“except to say that over a time scale of “a hundred years”, some heat does mix down to a depth of around 300m, which is why we have “committed warming” in the pipeline”
Ray, your above statement is absurd. Why do you think Willis is looking at annual changes in heat content down to 700 m? Please look at the work by Sidney Levitus and Josh Willis and others. The heat content changes below 300 meters, integrated over the entire ocean, are much, much, much more rapid and significant than you indicate as shown by time series cross sections of the ocean heat content. There is even evidence of annual-decadal heat content changes down to 1500 meters. Please ask Gavin or some of your other team members (or e-mail Josh Willis) about this issue. Your apparent misunderstanding of how dynamic vertical mixing processes manifest themselves in the real ocean, compromises your entire analysis. You have a conceptual picture of the ocean as a slowly changing laminar fluid, almost like a stratified geologic formation. Shallow waves and conductive transfer of heat are not the only process that ventilate the ocean. Turbulence accomplishes great and mighty things. Also, please post my last comment.
[Response: It is not possible to represent deep-ocean heat burial in any faithful way in a single-layer mixed-layer model. I am not claiming that that is the case. The ground rule here is to stick with the model Spencer actually used, and show how he got his result, how much latitude he gave himself for curve-fitting, and how indefensible his parameter choices are within the model limitations he himself chose. Within that framework, assuming global instantaneous mixing of heat down to 1 km is absurd. It’s what enables him to wipe out the unrealistically large interannual short-term fluctuations you would get by assuming a fluctuation in the radiative forcing as large as he assumed. You are making a good simulation of appearing to know what you are talking about, but as usual, you are just contributing to the noise level. –raypierre]
22 mai 2008 at 4:34 PM
Well, from what I see, the “debate” centers around how warm or cold the atmosphere is. But theres also the oceans ,and the land, and changes in those temps should be reflected in talk about overall changes in temps. And I don’t think they do , which is one reason why it’s so easy to keep the debate going. I started on this line of thought after a skeptic on another message board that I frequent stated that because the air is cooler after it rains, that proves that MMGW is a hoax. I don’t get his reasoning, he never could explain it, he obviously didn’t understand the basics of thermal dynamics, and heat transfer, but a lot of people bought that arguement. And I think that’s a result of the undue focus on air temps. I hope that clarifies my point.
22 mai 2008 at 4:37 PM
Dhogoza, I don’t think you can point the finger at religion–conservative or otherwise–but I have noticed a tendency of many advocates of Intelligent Design to adopt a strong version of the Anthropic Principle in arguments against climate change. In effect they argue that a world designed for human habitation must include negative feedbacks that maintain the state of the planet against our malign influences. This really isn’t a “Christian” idea. Indeed, you get similar arguments from the loons on the left, as well. We have no way of knowing what motivates Spencer. However, such an idee’ fixe’ has poisoned the mind of more than one scientist.
22 mai 2008 at 4:58 PM
It must be an inverse relationship*: NZ sheep numbers are in decline. Dairy cows are where the action is at the moment.
* But of course! We’re south of the equator so it must be inverse. Even the man in the moon is upside down!
[Response: You’re forgetting all the degrees of freedom Roy allows himself by his rules of the game. For example, the arbitrary linear combination of indices allows you to change the sign of indices if it suits your purpose. So, if the sheep population is going down, but you need something going up to do your curve fit, fine — just multiply by a negative number! For that matter,since Roy allows himself to pick any index he wants to do the forcing, if you don’t like sheep try doing the growing cow population. In order to fit the 20th century temperature, you only need a combination of indices that is flat (when smoothed out over some tens of years) and then goes up a bit at the end. The end part gives you the recent rise, the flat part gives you the mid-century, and then you get the early-century rise by diddling with the initial condition (assuming a large mixed layer depth). The fact that a fit can be done is completely devoid of content –raypierre]
22 mai 2008 at 6:10 PM
There’s a lot regarding the history of the intelligent design movement available on the web, including the entire transcript of the trial in Dover during which the conservative Bush-appointed federal district judge became convinced that it is nothing more than old testament-based creationism with a new label.
This really isn’t open to dispute.
And, in this country, old-testament creationism is almost entirely a christian point of view (which is NOT to say most christians hold that point of view, they don’t).
The phrase “intelligent design” arose as a reaction to a defeat in federal court of an attempt to teach creationism as part of the biology curriculum in the south. The publisher of an upcoming creationist biology text hurriedly replaced all occurrences of “creator” with “intelligent designer”, etc in hopes of being able to get it used in public school biology classes.
This is documented history.
Christy and Spencer are both Southern Baptists, and Christy at least has made clear (in writing meant for public consumption) that his faith and his experience having done missionary work in Africa influence his *political* beliefs regarding the climate change debate (but not his scientific work).
The intelligent design movement is a fundamentalist christian variant of creationism. When an avowed fundamentalist christian like Spencer claims that ID proves evolution false “coincidence” is not the first thought that comes to mind.
22 mai 2008 at 6:13 PM
Ray, I think Lee Grable’s point is important: The fact that we use the term “global temperature” to mean the average temperature on a two-dimensional surface rather than the three-dimensional ocean plus land plus atmosphere system of the earth has the potential to allow confusion. It isn’t necessarily obvious to the layman that a one- or two-year decline in measured mean surface temperature does not imply that the three-dimensional earth has cooled. Also, it doesn’t help that climatologists often use sloppy language when talking about this (which happens, of course, in any discipline where shorthand expressions are substituted for lengthy, but precise, formulations). Unfortunately, the answer to Grable’s question is “No, we can’t measure the heat content of the entire earth.”
[Response: But if you could measure the heat content of the entire fluid envelope of the Earth, how would that help you address Grable’s issue? Grable said something about a “biosphere,” which is what triggered my request for clarification. I would claim that the surface temperature — which is a comparatively easy thing to measure — is a relevant test of climate physics because a lot of the ocean response is indeed determined by the relatively shallow mixed layer. Naturally, one can do better with measurements of subsurface ocean temperatures and glacier volume (which affects latent heat content of the Earth), but the surface temperature does pretty well for a start. –raypierre]
22 mai 2008 at 6:19 PM
Raypierre states:
” 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,…”
Among the others who have definitely nailed that are:
http://www.cgd.ucar.edu/ccr/publications/meehl_additivity.pdf
Look especially at their figure 2(d). In order to reproduce observed climate, both anthropogenic and natural effects have to be taken into account. Natural effects alone fall well short of observations.
Raypierre also says: “this is not an exacting recipe: it’s hash — or Hamburger Helper — not soufflé…”
It might also be twenty four blackbirds baked in a pie. They seem to be trying to feed us crow.
22 mai 2008 at 6:24 PM
It is a fundamental principle of science, perhaps first enunciated by Leibnitz in Section 6 of his Discourse on Metaphysics, that a theory must be simpler than the data it explains. Thalt shall not over-fit.
I was trying to count parameters.
We’ve got two lesson 1 parameters (two weights but which sum to one, plus the ad hoc scaling factor making a total of two free parameters), then we’ve got one lesson 2 parameter (the mixed layer depth) and one lesson 3 parameter, the initial temperature anomaly, making a grand total of 4 free parameters plus he got to choose the data sets that he drove this model with in the first place. Did I miss any?
22 mai 2008 at 7:40 PM
“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.”
Ray, Lets talk some science. I have not personally insulted you, so I would ask for the same courtesy. Your above statement deals with choosing a correct mixed layer value to imput into this simple model. Presumably, your choice is driven by observational oceanography, no? (since that is obviously what you are referring to above) Can you document from the literature why you are closer to correct in choosing 50 meters, than Spencer is in choosing 1000 meters? That is a big difference, and I want to find out who is closer to being correct. It is quite interesting that on annual time-scales, quite rapid changes in ocean heat storage can be observed down past 700 meters, as pointed out by the Willis paper reference. Willis has even stated that a smaller, but still possibly significant fraction of the annual to decadal heat content variability takes place below 700 meters. You make a big deal about “instantaneous”, but even mixing in the upper 50 meters is not “instantaneous”, so it really boils down to how fast heat gets mixed to deep layers. Disqualifying his model on the “instantaneous” argument is a strawman. You have made a direct unsupported statement that Spencer’s model is flatly wrong in his choice of a mixing depth. I believe its you who may be wrong, and I challenge you to back up your hypothesis.
I also ask that Gavin drop in on this issue, and report to us what the coupled models depict on mixing depths. It seems to me that they must show deeper mixing than 50 M, since there is not enough mass in the upper 50 meters of ocean to account for the annual heat storage changes that are implied by observations for the the full integrated 700 meter volume of ocean.
Also, in my comment you chose not to post, I pointed out that the Wielicki graph clearly shows net TOA annual radiative fluxes of more than 1 W/m2. I also asked you flatly if the Wielicki graph in green (”net TOA anomoly”) is reporting the same quantity as the red graph labeled “top of atmosphere radiative anomaly”?
There have been some serious charges leveled against Spencer here, so lets put your analysis under the microscope and see how it stands up to closer examination.
[Response: Don’t worry about insulting me. In this business you can’t be too thin-skinned. I’ve been insulted by better than you and lived to tell the tale. Ask Ram about the “spherical mouse” sometime.
As for Wielecki, I’m not sure which red graph you are referring to, but if you mean the one at the top of the three-panel graph from the corrected version of the Science article,that is labeled “LW,” which, as I said in my response to Spencer Weart that is the TOA longwave radiative forcing. The one below that (”SW”) is the shortwave (solar) radiative forcing. “NET” is the sum, and is the green curve at the bottom, which is much smaller than the individual components, because of the substantial cancellation between longwave and shortwave components. Take note of the time scale. A lot of the remaining variability you see averages out over the annual cycle, and as I said, if you just take the part that actually correlates with PDO and SOI, you’d get an even smaller radiative forcing coefficient. You are welcome to try something similar with global radiative forcing fluctuation, but if you do it will be rather tricky to isolate the cloud effect, since you have the snow and ice albedo effect to deal with then, which are largely temperature-related feedbacks. 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. As you noted, that graph has very large fluctuations — which was my point. It’s way out of line with Wielecki’s NET curve.
Now, on to the interesting issue of heat transport to the deep ocean. Your problem is that you are trying to shoehorn the whole ocean into a mixed-layer picture. What makes the mixed-layer the mixed-layer is that wind-driven and buoyancy-driven turbulence mixes heat almost instantaneously, making it act as an isothermal slab. That allows you to compute the thermal inertia without having to deal with the transport explicitly. Large scale ocean currents do not work that way. There is another characteristic time scale, which is the time for transport of fluid from the surface waters into the deep ocean. While there can be individual convective plume events that go deep and quickly, these have to be weighted by the volume of ocean water involved. The reason I say that a global 1 km. mixed layer is oceanographically absurd is that all sorts of well-observed facets of the ocean go haywire if you assume a mixed layer to that depth — seasonal cycle, C14, CFC’s, and for that matter the rate of removal of CO2 from the atmosphere. Moreover, ENSO would go away if you mixed the tropical ocean that deeply. Now, for some purposes if you were looking at the very long term response to a very slowly varying radiative forcing, you might get away with treating the ocean with a deeper equivalent mixed layer. But that is not what is at issue here — Roy is forcing the model with an artificially pumped-up radiative forcing with a lot of short-term variability, but is then artificially suppressing the short-term response by mixing it away to 1km instantaneously.
[Response: Now, as to “accusations,” all I’ve done is shown you how Roy got his graph, and shown you the number of adjustable knobs he allowed himself to twiddle in order to get it. If you want to defend his parameter choices over mine, fine and good luck to you. –raypierrre]
22 mai 2008 at 8:16 PM
John E. Pearson–a quotation.
“Give me 4 parameters, and I will fit an elephant; five, and I will make him wiggle his trunk!”–John von Neumann
22 mai 2008 at 8:18 PM
RayPierre, You have confused me. You state that “the satellite data set confirms that the climate is warming” and send us to the RSS/MSU website http://www.remss.com/msu/msu_data_description.html#msu_amsu_trend_map_tlt
However the average temperature change of the four channels is MINUS 0.002 K/decade over the past 29 years. The greatest increase is the TLT channel at 0.175 K/decade (1.75 K/century). “Warming” should indicate an ongoing process. But none of the channels show any warming since 1998. For a process that occured in the past but is not currently happening, the past tense “warmed” is more appropriate.
[Response: You are being deliberately obtuse. The satellites track the GISS surface temperature record and reproduce the trend. If you want to know why your “global warming stopped in 1998″ meme is nonsense, just go check our earlier posts on the subject. –raypierre]
[Response: It’s worth adding that averaging the four channels makes no sense whatsoever. The stratosphere is involved in TMT, TTS and TLS and that is cooling because of ozone depletion and increasing CO2. - gavin]
22 mai 2008 at 8:22 PM
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]
22 mai 2008 at 8:35 PM
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]
22 mai 2008 at 9:27 PM
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.
22 mai 2008 at 9:51 PM
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.
22 mai 2008 at 9:56 PM
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.
22 mai 2008 at 10:23 PM
> 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.
22 mai 2008 at 10:28 PM
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.
22 mai 2008 at 10:30 PM
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).
22 mai 2008 at 10:40 PM
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]
22 mai 2008 at 11:19 PM
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]
22 mai 2008 at 11:46 PM
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.
23 mai 2008 at 12:07 AM
#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
23 mai 2008 at 12:09 AM
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
23 mai 2008 at 6:04 AM
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.
23 mai 2008 at 7:00 AM
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.
23 mai 2008 at 7:51 AM
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.
23 mai 2008 at 8:07 AM
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]
23 mai 2008 at 8:18 AM
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?
23 mai 2008 at 8:45 AM
“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]
23 mai 2008 at 10:33 AM
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 ?
23 mai 2008 at 10:51 AM
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?
23 mai 2008 at 11:20 AM
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?
23 mai 2008 at 11:49 AM
“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]
23 mai 2008 at 2:07 PM
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.
23 mai 2008 at 3:19 PM
#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.
23 mai 2008 at 3:56 PM
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…
23 mai 2008 at 4:19 PM
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.
23 mai 2008 at 4:21 PM
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.
23 mai 2008 at 5:33 PM
#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.
23 mai 2008 at 5:39 PM
#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.
23 mai 2008 at 6:15 PM
#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?
23 mai 2008 at 6:17 PM
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.
23 mai 2008 at 6:21 PM
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.
23 mai 2008 at 6:41 PM
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]
23 mai 2008 at 7:17 PM
More news from the Arctic that’s no cause for alarm: