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Berényi Péter at 10:12 AM on 27 May 2011Temp record is unreliable
#199 dana1981 at 09:08 AM on 27 May, 2011 But the presence of a DTR trend from 1950-1980 somehow doesn't mean the warming during that period was caused by GHGs. WTF?? There was in fact no warming between 1950 and 1980. Especially since it requires ignoring all other anthropogenic fingerprints Whenever you do not know what to say, start talking about something else. After all that's the way science is done. Or was it politics? -
Philippe Chantreau at 10:04 AM on 27 May 2011Temp record is unreliable
The so-called "Surface Stations Project" is a pile of idiotic nonsense that is of use only to those defined by Trenberth as "fools and charlatans." It has been proven irrelevant frome early on by the ones interested enough to follow up on it with real data analysis. It is not worth bothering with. -
Philippe Chantreau at 09:58 AM on 27 May 2011The Stockholm Memorandum
Please, DNFTT. Damorbel is the one who contradicted himself for the sake of argument on the 2nd law thread, in which he demonstrated, among other things, total confusion on Wien's law. It is not worth engaging, especially since the point he is trying to make here is both ill-defined and irrelevant. -
Chemware at 09:57 AM on 27 May 2011The Stockholm Memorandum
@6 e: Err, no. See Skeptic Argument #4. These guys (with one exception) fall into Doran's "Active Publishers" category, not "Climatologist" and related categories. -
Gareth at 09:36 AM on 27 May 2011The Climate Show Episode 13: James Hansen and The Critical Decade
With my knees, I don't do "spring" any more. Think of it more as a slow tentacular movement that involved planning, and cooperation from the tremendous team at UC. ;-) -
jonicol at 09:29 AM on 27 May 2011Carter Confusion #1: Anthropogenic Warming
Scaddenp. I am not sure how time series analysis is useful in model validation against paleoclimte since again one could only look for cyclical or repetitive functions to match repeated changes, which is essentially what the Milanovich cycles do so well. I would be interested if you could eleborate a little. Perhaps you could point to the parts of the Postma's article you referred me to which you think I should avoid. Thanks again for your helpful comments and this reference. John -
Albatross at 09:21 AM on 27 May 2011Temp record is unreliable
And BP @196, to fill the vacuity of his argument elects to argue a strawman about equants. Did you miss the bolded text from Zhou et al. (2009) and Zhou et al. (2010). You are making a fool of yourself BP. I remind you again that John Nielsen-Gammon, an author of Fall et al., agrees with Zhou et al. (2010). Unlike you,these guys are experts in this field and do in fact know better. Also, please read my post @192 very carefully, and actually look at the Figs. 2 and 3 in Zhou et al. (2010), better yet read the paper. "No, I do not think that, I am not American." But apparently you do when you mistakenly think that certain data from the US support your preconceived ideas and/or beliefs. Does your silence indicate that you implicitly agree that you fabricated the phrase "but the fast increasing DTR"? Please substantiate your claim or admit that you made it up. -
dana1981 at 09:13 AM on 27 May 2011Carter Confusion #2: Green Jobs
jonicol - as long as we're talking about costs, there are a whole lot of externalities not accounted for in the market price of coal power. It's actually an exceptionally expensive energy source - moreso than almost every source of renewable energy. But as long as the electricity bill is low, people tend to ignore those external costs. But if we're just talking jobs, renewable energy tends to beat out fossil fuels on that front too. So taking all costs into consideration, it's both cheaper and positive for employment. -
jonicol at 09:08 AM on 27 May 2011Carter Confusion #2: Green Jobs
Speaking of costs, I notice people are adding transport and fuel costs to those paid for coal produced power. Surely the cost of power from both government owned and privately owned genrating plants already includes thes components before sending out their bills to consumers. If the cost of building solar and wind power generators and their continuing operation were so competitive, why would we need a carbon tax to make the coal fired producers convert to solar etc? You do need to be care as to how you presentthese arguments I believe. -
dana1981 at 09:08 AM on 27 May 2011Temp record is unreliable
To be honest I don't usually pay a lot of attention to BP's comments (no offense intended - he just tends not to comment on posts I monitor the most). But I saw this comment and it just floored me. The lack of logic is staggering. In BP land, the lack of DTR trend from 1980-Present means the warming wasn't caused by GHGs. But the presence of a DTR trend from 1950-1980 somehow doesn't mean the warming during that period was caused by GHGs. WTF?? Of course as Tom Curtis notes in #195, DTR is influenced by other factors besides just GHGs (not to mention the world being larger than the USA), so concluding that the warming wasn't anthropogenic just because the DTR trend isn't evident during that period is, well, it's not very wise. Especially since it requires ignoring all other anthropogenic fingerprints, not to mention that pesky...what's the word I'm looking for? Oh yeah, physics! Sorry BP, but you really need to think about what you're arguing here. It's patently absurd. -
KR at 08:57 AM on 27 May 2011Temp record is unreliable
Berényi - Straws, grasping at, see here. You, of all people, know that regional data can give contradictory indications to full global data. Yeesh. -
Berényi Péter at 08:29 AM on 27 May 2011Temp record is unreliable
#195 Tom Curtis at 07:56 AM on 27 May, 2011 Even more bizzare, BP seems to think that the continental US is the Earth. If we check the data for Australia, which has a similar area to the continental US, we find a clear reduction in DTR with a trend of -0.05 degrees C per decade. No, I do not think that, I am not American. But as far as I know the SurfaceStations project is not a global one yet, specifically it is not extended to the surface stations of Australia. Therefore you can not tell us how much of the Australian trend is due to poor siting and how much of it is genuine. The aerosol card is also a convenient joker, for global atmospheric aerosol concentrations are not measured properly (and never were). -
Rob Honeycutt at 08:17 AM on 27 May 2011Even Princeton Makes Mistakes
Jay... You also might note that, as best as I can tell, Happer was on the steering committee as a JASON that produced a report on greenhouse gases in 1990. Over 20 years ago. That wouldn't make him an expert then or now.Response:[DB] Fixed text.
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Berényi Péter at 08:01 AM on 27 May 2011Temp record is unreliable
#192 Albatross at 06:26 AM on 27 May, 2011 What is critical to note is that without including anthro GHGs, the model projections in Zhou et al. (2010) were unable to produce the observed trends and patterns in both mean temperature and DTR What is critical to note is that without including equants, the model projections in Ptolemy (~150) were unable to produce the observed planetary orbits So what? Does that make equants real? Of course if you suppose the model is basically correct, you can prove (using observations) the equant can't be located at the center of the deferent circle (and neither one is colocated with the center of the Earth). Same logic. -
Riccardo at 07:58 AM on 27 May 2011The Stockholm Memorandum
damporbel #5 "Nobel Prizes in science are awarded for outstanding progress in science," Indeed! Progress, not denial. Anyway I was just saying that this memorandum is going to be ignored by skeptics, which your comment apparently confirms. -
Tom Curtis at 07:56 AM on 27 May 2011Temp record is unreliable
One bizzare aspect of Berényi Péter's campaign to retract the fingerprints article is that it assumes that only one effect can be influencing the climate at any one time. Specifically, increasing GHG concentrations and increasing aerosol load will both decrease the Diurnal Temperature Range, although the former warms the globe while the latter cools it. In contrast decreasing GHG concentrations and decreasing aerosol load will increase DTR, although the former cools the globe and the later warms it. As it happens, over the continental US, from the 1950s to 1980, both GHG concentrations and aerosol load were increasing, generating a significant reduction in DTR, but since the early 1980's, GHG concentrations have been increasing but aerosol load has been decreasing. Absent the effect of GHG, we would expect an increase in DTR over that period. That we do not see it is therefore evidence of GHG warming (although not the strongest evidence). Even more bizzare, BP seems to think that the continental US is the Earth. If we check the data for Australia, which has a similar area to the continental US, we find a clear reduction in DTR with a trend of -0.05 degrees C per decade. The annual fluctuations are, of course, very large, and dominated by variations in humidity.
Australia is also not the Earth, but the clear difference shows it is foolish to draw a conclusion about global trends from a study of 1.8% of the world's surface area.
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Dave123 at 07:41 AM on 27 May 2011Even Princeton Makes Mistakes
Dr. Jay Cadbury, Ph.D. @96 The forcing effect of CO2 is different from the radiative effect. If Happer wants to play, the same rules apply to him as everyone else. Do the math. The radiative calculations are out there. Tell us why they're wrong. Qualifications don't matter if people don't put the skills they learned to use. Since you know him Jay, does this guy EVER get in an equal-to-equal discussion with anyone on this, or is he episystemically closed? I know some senior profs get that way. But I look at it this way: Earning a Ph.D. did not grant me the privilege of opining and it being respected because I had a Ph.D. It was a lifetime sentence to proving what I said was true. The Ph.D. part means people expect me ( and you and everyone else with a Ph.D.) to be able to do it. Getting tenure or a named chair at a University only raises that expectation. Happer has the ability to do the math, to challenge whatever he wants and instead he's quoting the classics in polemical way. Happer in my view is letting down the academic tradition by his fact-free opining. One last point: when you say- 'leads him to claim the possibility of extreme weather will be weaker than anticipated"...are you attempting to move the goal posts here? That is not the least of Happer's positions. -
scaddenp at 07:33 AM on 27 May 2011Can we trust climate models?
"Clearly some tweaking went on in an effort to make the hindcast similar to instrumental readings." Can you substantiate that please? Hindcast do have a problem in that proxies have to be used to estimate forcings, but this is fit to proxy not temperature on the whole. As to "not looking good so far" - we had hottest year on record in GISS despite deepest solar minimum since satellite measurements begun but agreed its not accelerating. Would you expect it to when compare forcings change in CO2 cf forcing from sun over same period. Do you seriously expect that temperatures are going to decline as solar cycle revives or are you expecting solar minimum to last till 2100? -
grypo at 07:32 AM on 27 May 2011The Stockholm Memorandum
This is about sustainability, of which climate is just a part, albeit, an important one. Whether or not they are all experts in climate science is irrelevant. It's an all encompassing look at humanity going into the future. Even scientists that are skeptical of the fat-tails on climate sensitivity don't dismiss the risk that these pose to human sustainability. -
les at 07:30 AM on 27 May 2011The Stockholm Memorandum
Do I not get an answer :( -
Rob Honeycutt at 07:25 AM on 27 May 2011Even Princeton Makes Mistakes
Mike @ 95... Princeton can't screen how a tenured professor chooses to represent his credentials but I'd bet dollars to doughnuts there are some meetings going on at Princeton following Happer's piece that are very close to coming to fisticuffs. Happer has clearly chosen to make a public and highly politicized statement on behalf of the George C Marshall Institute BUT chosen to identify himself using his Princeton credentials (and curiously omitting his GMI connection). Princeton would have every right to be utterly furious about this kind of activity. It'll be curious to see if the university responds publicly in some manner. -
damorbel at 06:57 AM on 27 May 2011The Stockholm Memorandum
Re Response to #5 It is not about what you said, The title of the event is "3rd Nobel Laureate Symposium on Global Sustainability" Yes V. Ramanathan has written extensively on climate related matters, but he is not a 'Nobel Laureate'. Just what is he there for, to guide the Symposium towards its conclusions?Response:[DB] Please read the original post then. And then the materiel linked within it. This is all information you could find out for yourself.
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Albatross at 06:53 AM on 27 May 2011Temp record is unreliable
More from Zhou et al. (2009) [with Vose a co author]: "In general, the magnitude of the downward trend of DTR and the warming trend of Tmin decreases with increasing precipitation amount, cloud cover, and LAI, i.e., with stronger DTR decreasing trends over drier regions. Such spatial dependence of Tmin and DTR trends on the climatological precipitation possibly reflects large-scale effects of increased global greenhouse gases and aerosols (and associated changes in cloudiness, soil moisture, and water vapor) during the later half of the twentieth century." So the decrease in DTR from elevated GHGs is (and should be) greatest where the signal is not swamped/muted by moisture-- that is in should be greatest in Arid and semi-arid areas. An interesting question is how changing atmospheric moisture, rainfall and cloud in response to AGW are affecting DTR. This is another reason why the seasonal fingerprint (winters warming faster than summers) is a more robust fingerprint. But it would be a huge mistake for the contrarians and those in denial to claim that issues with the DTR is a silver bullet that refutes the theory of AGW, or that is demonstrates that warming in the satellite era is not attributable to enhanced GHGs, especially if they choose to ignore/neglect the numerous other fingerprints in the process. -
damorbel at 06:50 AM on 27 May 2011The Stockholm Memorandum
Re #3 you wrote "This gathering had such heavy hitters in their fields" Very true. But I am a loss to know why the expertise of Werner Arber, awarded the Nobel Prize in Medicine/Physiology in 1978 for the discovery of restriction enzymes and their application to problems of molecular genetics; should be put forward as a reccommendation. Surely he should be reccommended for his expertise in climate science. I think it is very demeaning, not to mention his relevant climate expertise; it might be thought he was some kind of interloper which is almost certainly not true. -
The Stockholm Memorandum
damorbel, The panelists in this gathering are the ones who form the consensus in the first place. What point are you trying to make? -
Dr. Jay Cadbury, phd. at 06:47 AM on 27 May 2011Even Princeton Makes Mistakes
I think Happer is pretty qualified to speak on climate science considering he has studied the greenhouse effect intimately and the radiative chemistry of the physics aspect. I don't know if he is qualified to speak about weather patterns, sea level or other possible effects of climate change but since he is claiming that the forcing of co2 is weak, that leads him to claim that the possibility of extreme weather will be weaker than anticipated. -
damorbel at 06:38 AM on 27 May 2011The Stockholm Memorandum
Re Response to #1 Ramanathan has not yet been awarded a Nobel Prize Re #4 Riccardo, you wrote "Skeptics that can not accept the scientific consensus of literally thousands of climate scientists." Which of the Nobel Prize winners taking part in the Symposium (or any other Nobel Prize winner for that matter) was awarded a Nobel Prize for, as you say: "accept[ing] the scientific consensus of literally thousands"? Nobel Prizes in science are awarded for outstanding progress in science, not for citing what is known already 'by the consensus of literally thousands'!Response:[DB] Strawman. I never said Ramanathan was a Nobel Prize winner. I gave you a participant list which identifies who the prize winners are and what their areas of note were. I then made the observation that the esteemed Dr. Ramanathan was on the list. Please do try and read more carefully.
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Albatross at 06:37 AM on 27 May 2011Temp record is unreliable
BP @191, Please substantiate this "but the fast increasing DTR is inconsistent with model predictions", in particular the reference to "fast increasing". Vose et al. (a extended conference abstract it appears) state that: "Both maximum and minimum temperature increases from 1979-2004 whereas the DTR is basically trendless." And "Given the similarity between maximum and minimum temperature, the trend in the DTR (-0.001 °C dec-1) is not statistically significant at the 5% level." No reference to increasing, so one has to wonder how you arrived at the conclusion that DTR is rapidly increasing. And please actually read Zhou et al. (2010). -
scaddenp at 06:31 AM on 27 May 2011Can we trust climate models?
GC "Will similar trends extend over the next 100 years? I would wager $10,000 that it will not but sadly I won't be around to collect my winnings." Well I would bet the temperatures will follow the total forcings whatever they actually are and base that bet on established science. You would be basing your bet on what? Hope? Good luck? Pity - my retirement savings could do with a boast. As to history channel - well firstly I am in NZ, dont have access to such a channel and frankly prefer to get my science from published papers, or even my colleague across the passage whose speciality this is, rather than the biases of some tv director. And what on earth is the relevence? The science so far agrees LIA was indeed global event (though far less pronounced in SH than NH), and the response of climate to the forcings of the time. Are you implying the same forcings have suddenly come (the deep solar minimum) which somehow overwhelm all the other forcings.? -
Albatross at 06:26 AM on 27 May 2011Temp record is unreliable
KR @186, Dana@187, It certainly is entertaining to watch those in denial about AGW and certain contrarians pounce on this finding by Fall et al. (2011) concerning the DTR over the US. John Nielsen-Gammon, one of the authors of Fall et al. agrees with the findings in Zhou et al. (2010). Also, as has been noted elsewhere, the findings by Fall et al. bring the model projections concerning DTR into closer alignment with observations, at least for the contiguous USA. The obfuscators should also look carefully at the Figures in Zhou et al. For example, Figs. 2 and 3 show that the observed and modeled decrease in DTR was not statistically significant over large portions of the contiguous US between 1950 and 1999. But step back and see what was observed and modeled for the globe, you now anthropogenic global warming. Zhou et al. say, "Evidently the ALL [natural and anthro forcing]simulations reproduce the global signal much better than the regional variations." What is critical to note is that without including anthro GHGs, the model projections in Zhou et al. (2010) were unable to produce the observed trends and patterns in both mean temperature and DTR (see their Fig. 5). A caveat though, Zhou et al. also conclude that: "The model simulated warming in Tmax and Tmin and the general decrease in DTR may reflect large-scale effects of enhanced global GHGs and direct effects of aerosols. The strong and persistent increase in DLW, which mainly reflects GHGs effects of a warmer and wetter atmosphere and to some extent of a warmer surface, is the dominant global forcing in explaining the simulated warming of Tmax and Tmin from 1950 to 1999, while its effect on DTR is very small. Decreases in DSW due to enhanced aerosols and PRW contribute most to the simulated decreases in DTR." -
Berényi Péter at 06:19 AM on 27 May 2011Temp record is unreliable
#186 KR at 04:52 AM on 27 May, 2011 observed diurnal temperature range (DTR) changes are actually much larger than predicted by models I see. You say the proposition "If global warming is caused by an increased greenhouse effect, then the planet should warm faster at night than during the day" is a false one. That's certainly a possibility. However, the fingerprint thing even in this case should be retracted. Because if A => B is false, the truth-value assigned to B should also be false. That false proposition reads "The planet is warming faster at night than during the day." In other words, you are claiming the temperature record is unreliable in this respect, which is exactly what Fall 2011 says. Or, alternately, you can insist the temperature record is reliable, but the fast increasing DTR is inconsistent with model predictions. In that case computational climate models (which, as you claim, indicate much smaller changes) are falsified. -
Riccardo at 05:45 AM on 27 May 2011The Stockholm Memorandum
Skeptics that can not accept the scientific consensus of literally thousands of climate scientists will dismiss this Memorandum of "the dirty dozen" of Nobel Prize winners, no doubt. -
shoyemore at 05:34 AM on 27 May 2011The Stockholm Memorandum
This gathering had such heavy hitters in their fields that the word "awesome" can only apply. I mean - Amartya Sen, Economics, and Murray Gell-Mann, Physics! Sen has moved from places like Oxford to Yale to Chicago. Gell-Mann was an equal sparring partner to the legendary Richard Feynmann, and shared a Nobel for theorizing the existence of quarks. The bathos of it all comes when you consider this set of speakers about to attend the "Heartland Institute Conference on Climate Change" with the theme "Restoring the Science". Scott Mandia on the Heartland Institute Conference As Michael Tobis almost said - is science that bad it needs the Heartland Institute to save it? It's like leaving Harvard University to attend Hamburger University. -
mclamb6 at 05:34 AM on 27 May 2011Temp record is unreliable
BP @ 189--the implication of this statement: 'warming trend in the data at least since 1980 is not caused "by an increased greenhouse effect", but something else.' is clearly that prior to 1980, the warming was due to an increased greenhouse effect. You provide some wiggle room "at least since", but it's a fairly weak caveat. -
Mike Lemonick at 05:34 AM on 27 May 2011Even Princeton Makes Mistakes
Skywatcher (68) asks: "What are Princeton's policies on making statements like these when using their name as authority? It is one thing for Happer to make this gish gallop of verifiable lies and unscientific disinformation when writing personally, but it is something else when writing in his professional capacity, or using his position at Princeton as 'authority'. Especially when he is not an actively publishing member of the field of science that he is dismissing and insulting" Like the author of the post we're all commenting on, you seem not to understand how universities work. Happer is a member of the Princeton faculty. He's entitled to identify himself as such, even when saying stupid things. Princeton doesn't, and really can't, have a "policy" preventing him from doing so. Universities aren't like corporations, where you're required to vet public statements before making them. And I happen to know that colleagues HAVE confronted him on his nonsense. It clearly hasn't had any effect. -
DSL at 05:29 AM on 27 May 2011Even Princeton Makes Mistakes
You know, Dave, they found Atlantis, although it turns out it wasn't a continent but was, rather, sort of incontinent. On Mu, there was a spelling error. Everyone thought it was "continent," but it was really supposed to be "content"--the Lost Content of Mu. Mu is an obscure continental spelling of "Moo," which of course is a reference to cows. The lost content of cows: milk. Every morning when you eat your continental breakfast, choose the lost content of Mu. Got Mu? You might even read this before it gets deleted. -
DSL at 05:20 AM on 27 May 2011Even Princeton Makes Mistakes
Mods, you might expand the comments policy or create an article (with a link above the comment box) that points out what happens when a Gish or a completely-unevidenced-but-soooo-obvious-you-idiots-absolute-Truth-,-pardon-me-,-TRUTH appears. I say this knowing full well how DB loves to repeat/copy "Welcome to Skeptical Science . . ." It might be good to work through a few example posts to define "quality" as SkS sees it.Response:[DB] I do not love to type it, which is why I cut & paste it. ;)
I refer to it as the reading of one's SkS Miranda rights...
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Berényi Péter at 05:19 AM on 27 May 2011Temp record is unreliable
#188 dana1981 at 04:58 AM on 27 May, 2011 you're admitting the warming from 1950-1980 was largely anthropogenic, yet even though atmospheric CO2 has continued to grow rapidly since 1980, somehow it's no longer causing warming? Are you confabulating? A have never admitted such a thing. Read carefully: warming trend in the data at least since 1980 is not caused "by an increased greenhouse effect", but something else. How can you read it as "the warming from 1950-1980 was largely anthropogenic" is beyond me. On top of that according to GISS there was hardly any warming between 1950 and 1980. Are you trying to say no-warming is also anthropogenic?
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dana1981 at 04:58 AM on 27 May 2011Temp record is unreliable
I mean seriously, think about what you're saying. Even ignoring all the other mounds of evidence for anthropogenic warming, you're admitting the warming from 1950-1980 was largely anthropogenic, yet even though atmospheric CO2 has continued to grow rapidly since 1980, somehow it's no longer causing warming? Is that really what you're arguing? That the laws of physics were different in 1950-1980 than 1980-2011? -
dana1981 at 04:54 AM on 27 May 2011Temp record is unreliable
BP #185 -"Therefore we know warming trend in the data at least since 1980 is not caused "by an increased greenhouse effect", but something else."
Is that a joke? Because one 'fingerprint' isn't obvious in one study over one period, we can ignore all other evidence and physics and blame the warming on some other unknown cause? All I can say is wow. -
KR at 04:52 AM on 27 May 2011Temp record is unreliable
Berényi - The original contention by Watts was that the long term mean global temperature was not rising, and the indication was an artifact of distorted data. Are you claiming that this is correct? Watt's data shows that it isn't. The issues with day/night temperature range are quite different - you might profitably look at Braganza et al 2004, who note that observed diurnal temperature range (DTR) changes are actually much larger than predicted by models, most likely because of insufficient accounting for temperature driven cloud increases in those models. From that paper: "Observed DTR over land shows a large negative trend of 0.4C over the last 50 years that is very unlikely to have occurred due to internal variability. This trend is due to larger increases in minimum temperatures (0.9C) than maximum temperatures (0.6C) over the same period." Your call to "retract" the fingerprint statement is quite premature. But all that aside - Watt's initial accusations did not pan out, and shifting to the DTR is indeed a shifting of the goalposts. -
Berényi Péter at 04:36 AM on 27 May 2011Temp record is unreliable
#184 Albatross at 03:11 AM on 27 May, 2011 Zhou et al. (2010): "Observations show that the surface diurnal temperature range (DTR) has decreased since 1950s over most global land areas due to a smaller warming in maximum temperatures (Tmax) than in minimum temperatures (Tmin). OK. This paper does not do any DTR data analisys of its own, it uses Vose 2005 (Maximum and minimum temperature trends for the globe: An update through 2004), which says: "a widespread decrease in the DTR was only evident from 1950-1980." Indeed.
And that with no correction for station quality whatsoever.
Therefore we know warming trend in the data at least since 1980 is not caused "by an increased greenhouse effect", but something else. That fingerprint thing should really be retracted.
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les at 04:20 AM on 27 May 2011The Stockholm Memorandum
1 damorbel It's a bunch of folks reflecting on a verity of global issues facing all of us. Why do they have to be experts in just one particular disceplen?!?!? -
damorbel at 04:07 AM on 27 May 2011The Stockholm Memorandum
Which of these Nobel Prize winners has published on climate matters?Response:[DB] The Symposium participant list can be found here. Short intro/bio on each.
Note that V. Ramanathan was a participant (he literally "wrote the book" on radiative-convective climate modelling).
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Charlie A at 03:28 AM on 27 May 2011Can we trust climate models?
#26 Kevin C says "You describe it as a 'a simple linear + 1 lag model' - do I infer correctly from that that you are using two terms: one exponential lag and one which is a direct feed-through of the forcing (i.e. a delta-function response)?" Here are some notes on how to make a simple spreadsheet that, given a set of forcings either projected or historical, will generate a global average temperature anomaly almost identical to the GISS-E AOGCM. I initially had several misunderstanding about the toy model, mostly because terms were used differently than in engineering fields. For example, a step change in forcings was called an impulse forcing. The points below hopefully make it easier to understand, or at least to avoid several of the misunderstanding I had. 1. The model works with changes in forcings causing changes in global temp anomaly. The estimated global average temp is then calcuated as a running sum of the temperature changes. 2. This works because the earth heat up in response to a step change in forcing, and the warmer earth radiates more energy, cancelling out the step in forcing. The time it takes for the temperature of the earth to respond to a step increase (or decrease)in forcing can be approximated by an exponential with time constant in the 2 to 5 year range. Physically, this corresponds roughly to the time it takes to heat up the well mixed layer of the ocean (i.e. the layer above the thermocline .... typically considered to be an equivalent depth of 60 or 70 meters). 3. The ultra simple model is just a single multiplication. X watt/m^2 step increase in forcing will cause a step increase of (lambda * X) degrees. delta T = lambda * delta F. 4. The 1 box model is the same as above, except that the step change in forcing results in the same temperature delta, but over a period of a few years rather than instantaneously. The step change in forcing is an impulse in the derivative. The impulse response is simply exp(-T/tau). The response is delta T, not T. Specific example: if e-folding time (time constant) is assumed to be 2.6 years, then for each year after the step increase in forcing, the increase in delta T will be about 68% of the increase from the previous year. Exponentially decaying series never go to zero, but including just approximations of the first 6 terms (and a scaling of volcano forcing) resulted in a toy model that emulated the GISS-E model with an error of only about 0.027C rms. An exponential decay of 2.6 year time constant starts off as 1, 0.68, 0.46, 0.32, 0.21, 0.15. If I truncated the series after those 6 terms, and then normalize the sum, the rounded off coefficients are 0.36, 0.24, 0.16, 0.11, 0.08, 0.05. 5. This simplified version can easily be hardcoded into a spreadsheet. A. download the GISS-E forcings for 1880-2003, and then add 10 or 20 rows above for years prior to 1880 and fill the forcings with zeros. B. Setup up a column, Delta F, which is nothing more than forcing change from the previous year. C. Setup a cell called Lambda. D. The delta T for each year is simply lambda* (0.36* delta F + 0.24*delta F of the prior year + 0.16*delta F for the year before that ...... on through the 6 terms). E. Now you have delta T for each year. F. The estimated temperature is the running sums of delta T. That's it. Nothing more is needed to emulate GISS-E model anomaly temps to within about 0.5 C rms error. Before calculating error, be sure to baseline the two anomaly temps series, which have about 0.12C offset. 6. The plot of this simple model, though, shows excessive response to volcanic events, which indicates that the GISS-E model is less sensitive to stratospheric aerosol forcings of volcanoes than to other forcings. A 30% reduction in the volcano forcings resulted in a better fit. 7. A more elegant method of implementation in a spreadsheet would be to set up a coefficient array and then do a dot product array multiplication to get the estimated delta-T. Note that, if the forcings are in a vertical column, latest year at the bottom, then for the array multiplication to work properly the coefficients have to decrease going from right to left. I'll put together than spreadsheet today or tomorrow, and hopefully find a place to post it. -
Albatross at 03:26 AM on 27 May 2011Monthly Climate Summary: April 2011
CW, Re "Moisten up the air mass within the cold trough and you've diminished the kinetic energy from which the tornadic cells evolved." This is a nonsensical (and unsupported) statement. Read the papers above [you might also want to read Crook (1996)] and please stop talking though your hat for the sake of arguing. -
Dave123 at 03:18 AM on 27 May 2011Even Princeton Makes Mistakes
Depends on the faculty club I suppose. My whimsy was more social than political. But at the risk of saying to much about myself, I still remember my shock at learning the my retiring undergrad prof of P.Chem. was a serious believer in the lost continents of Atlantis and Mu. But overall, he's in a position where no one can reasonably induce him to respond in a factual fashion. -
Albatross at 03:11 AM on 27 May 2011Temp record is unreliable
Not so fast BP and Poodle, Zhou et al. (2010): "Observations show that the surface diurnal temperature range (DTR) has decreased since 1950s over most global land areas due to a smaller warming in maximum temperatures (Tmax) than in minimum temperatures (Tmin). This paper analyzes the trends and variability in Tmax, Tmin, and DTR over land in observations and 48 simulations from 12 global coupled atmosphere-ocean general circulation models for the later half of the 20th century. It uses the modeled changes in surface downward solar and longwave radiation to interpret the modeled temperature changes. When anthropogenic and natural forcings are included, the models generally reproduce observed major features of the warming of Tmax and Tmin and the reduction of DTR. As expected the greenhouse gases enhanced surface downward longwave radiation (DLW) explains most of the warming of Tmax and Tmin while decreased surface downward shortwave radiation (DSW) due to increasing aerosols and water vapor contributes most to the decreases in DTR in the models. When only natural forcings are used, none of the observed trends are simulated. The simulated DTR decreases are much smaller than the observed (mainly due to the small simulated Tmin trend) but still outside the range of natural internal variability estimated from the models." As for "There is no escape route." Indeed, Watts has been hung by his own petard. And Fall et al. (2010) is not without its problems. I will concede that DTR is perhaps not the best fingerprint for AGW, just because it is affected by so many factors other than GHGs, and there are clearly problems measuring it. The changes in the seasonal patterns (winter warming faster than summer) is a robust fingerprint. Looks like SkS will have to do a post to refute the chatter in denier circles about the Fall et al. paper. -
Berényi Péter at 03:06 AM on 27 May 2011Temp record is unreliable
#182 KR at 02:52 AM on 27 May, 2011 And with a lovely grinding noise the goalpost is moved. KR, you are smarter than that, it's about attribution. It is a serious issue, can't make it go away by simple handwaving. -
KR at 02:52 AM on 27 May 2011Temp record is unreliable
thepoodlebites "The best-sited stations show no century-scale trend in diurnal temperature range in the lower 48 states." And with a lovely grinding noise the goalpost is moved. Watts started that project to "demonstrate" that poor siting induced a long term false trend in mean temperatures. It did not, as his analysis demonstrated. He found higher variances in poorly sited stations - no huge surprise. And now he's claiming that's invalidating the temperature record? Please...
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