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barry1487 at 15:19 PM on 21 April 2012First Look at HadCRUT4
Heh - skywatcher, apologies. -
barry1487 at 15:18 PM on 21 April 2012Weird Winter - March Madness
Yeah, those are great vids, and very informative on the jet stream, which has hitherto been a bit of a mystery to me. Well done, greenman. -
barry1487 at 14:50 PM on 21 April 2012First Look at HadCRUT4
DB F & R 2011 methodology gives statistically significant trends for shorter periods, yes, but that was not what skywalker was refering to. "1. skywatcher was responding to the claim by fydijkstra that "the warming trend in the last 15 years is zero"; skywatcher ably showed the trend to not only be non-zero, but positive." Just off the first graph that skywatcher diaplyed, one can see that the uncertainty is greater than the trend. Therefore one cannot ably demonstrate a warming trend 'for the last 15 years' from that. So I guess you are saying that the addition of the second observation, warming over the past 30 years, makes skywatcher's conclusions solid. Is this because we take the 30-warming trend to be the null hypothesis, and that the recent 15 year trend does not invalidate it? I ask because I have been among the many (inlcuding commenters and contributors here and Tamino etc) who rebut 'skeptics' who use non-statistically significant trend estimates to make strong claims. Here's another way of doing it, but I don't think it's quite right either: Trend 1967 to 1996 inclusive (30 years, to overcome noise)
Now extend to the most up-to-date data point (1967 - Dec 2010?).
Not only has the trend continued, it has increased.
But, the trend difference is not statistically significant.
I am leery - perhaps overly leery considering very low skill in stats - of using non-statistically significant trends to say very much at all.
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victull at 14:09 PM on 21 April 2012Global Surface Warming Since 1995
dana1981 Given that global warming is about whether or not the Earth 'system' is warming over time or not, it should be clear to all what is defined as the 'system' and what is a significant time. I think of the 'system' as a spherical shell of air, water and land, bounded by the bottom of the ocean and land surface and the top of the atmosphere. This shell is about 100km thick and has energy entering and leaving at the top and entering from geothermal at the bottom. To stay at equilibrium, the top balance has to be slightly cooling in order to offset the slight warming from the bottom of the oceans. A separate issue is what portion of the warming is caused by human releases of CO2. That portion could be thought of as more than 100%, for if the Earth system would have been naturally cooling and it is now warming, the CO2 effect is offsetting the cooling and then adding some extra warming. Figure 2 suggests that CO2 GHG warming portion is about 100% because the lack of surface temperature increase over 17 years is all due to the cooling effects of Solar, ENSO and Volcanoes. Solar and Volcanoes are accepted as external to the Earth 'system' - ENSO is not - at least over a significant time. Which brings us to what is a significant time. The figure of 15 years has been quoted - 17 years in the above article. My question is whether ENSO should properly be treated as an external forcing over this time period. If not its effects should be excluded from Fig 2. -
Daniel Bailey at 14:06 PM on 21 April 2012Roy Spencer finds negative feedback
Agreed. Without evidenciary links to supportive works in the literature, it's an exercise in climastrological mathturbation. -
skywatcher at 13:59 PM on 21 April 2012Roy Spencer finds negative feedback
#3 - a handwaving attempt to dismiss the evidence of a whole range of branches of science, doesn't cut it for me I'm afraid. Re-read Knutti and Hegerl. Just one example: With low climate sensitivity, how do you get glacial-interglacial cycles, which are clearly (from timing and frequency) forced by the small Milankovitch orbital variations? -
barry1487 at 12:49 PM on 21 April 2012Why Are We Sure We're Right? #1
JimF@30, An acquaintance who is a scientist that studied under John Houghton allowed me to question him about the greenhouse effect and AGW. I mentioned skeptics, and looked for his opinion. I had a couple of long chats, and came away with the realization that he had not given me any kind of position at all on the matter, only what he thought were relevant scientific points (Ari's reply in the OP smacks of). I didn't know what he thought about the 'issue'. "Here," I thought at the time, "is a scientist." (Not long after, one of my (arts) students after 6 months of informal chats in the classroom and pub on climate change, complained I'd said much but given no opinion. I was surprised and pleased as punch - but didn't mistake myself for a scientist :-) I think skepticalscience treads a line between science and activism. Dikran's response was the one I related to most. His clear concession to uncertainty inspires the most trust in what he might say. Whereas the bald certainty of much 'skeptic' commentary inspires no confidence from me. I sometimes make the argument that greater uncertainty is actually a greater impetus to do something. If the hazard is potentially lower because we don't know the bounds as well as we thought, that also means (naively) that the hazards are also potentially greater. But this is not a good 'sell' for an activist, because action is encouraged by bold statements, not deference to uncertainty. The irrational 'skeptics' equate uncertainty with lowering the bottom AND top end of the risk scale instead of widening it. -
Brendon at 12:22 PM on 21 April 2012Why Are We Sure We're Right? #1
I believe in AGW and I think I am correct. However this is not my opinion, I just go with what the science is telling us. If new research were presented that showed us why AGW is not a concern, that some strong negative feedback will prevent higher temps, then so long as it were scientifically sound and withstood the test of proper peer-review, then my "belief" would also change. At the moment that seems unlikely for both warming and acidification. Uncertainty however, is not reason for inaction or complacency. -
barry1487 at 12:07 PM on 21 April 2012GISTEMP: Cool or Uncool?
UAH satellite data: trends for the poles. North Pole 0.47C/decade South Pole -0.05C/decade http://vortex.nsstc.uah.edu/public/msu/t2lt/uahncdc.lt (see comments above for caveats) -
barry1487 at 11:54 AM on 21 April 2012First Look at HadCRUT4
Robert Murphy @ 11 "Hadcrut4 and GISS both show a warming over .11C since the beginning of 1998" Using the skepticalscience trend calculator, I get ~0.083 for both data sets, and the trends are not statistically significant. Did you run trends including more recent data? If so, what was the stat sig for those? skywatcher @ 13 The trend since 1996 is not statistically significant. Caution.Moderator Response:[DB] "The trend since 1996 is not statistically significant."
Actually, 2 main points:
1. skywatcher was responding to the claim by fydijkstra that "the warming trend in the last 15 years is zero"; skywatcher ably showed the trend to not only be non-zero, but positive.
2. Tamino, in his The Real Global Warming Signal thread, showed that (once controlling for exogenous factors) not only is the warming trend since 1996 statistically significant, but that the trend in all 5 datasets examined showed statistically significant warming since 2000.
QED
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LazyTeenager at 11:30 AM on 21 April 2012Why Are We Sure We're Right? #1
The thing which seals it for me is climate skeptic tactics. 1. Relentless attempts to discredit climate scientists or in fact any one who nay says their debating points. 2. Reliance on debating points which are wrong and which they show no inclination to verify for truth. 3. Persistent use of logical fallacies. 4. Cheating and manipulation by a significant number of climate skeptics, particularly the politicals. 5. Consistent promotion of crank science. 6. Lots of arm chair philosophy, but very little science even if you could do the experiments in your kitchen or basement. If they had a strong position they would not need to do any of that. -
muoncounter at 10:58 AM on 21 April 2012Why Are We Sure We're Right? #1
In case you missed it, we're well past the point of 'very low sensitivity.' -
dr2chase at 10:25 AM on 21 April 2012Why Are We Sure We're Right? #1
It may not be a sensitivity thread, but sensitivity modifies our alarm, and the degree to which it matters whether we are right. Very low sensitivity means it doesn't really matter. -
muoncounter at 09:38 AM on 21 April 2012Why Are We Sure We're Right? #1
This is not a sensitivity thread; that's a fine point of the type Scott Denning cautions against. Whether or not we have established the exact sensitivity does not alter the basic facts. Physics doesn't care. -
Rob Honeycutt at 09:07 AM on 21 April 2012Why Are We Sure We're Right? #1
When the IPCC states that climate sensitivity below 1.5C is unlikely, they are basing it on a lot of data from a lot of sources. The more interesting recent research on this topic has been essentially clipping the long tail of the distribution. In AR4 they stated that sensitivity above 4.5C could not be ruled out, but newer research is starting to rule it out. Which is a very good thing. 4.5C is ominous enough for me. Hell, 3C is pretty darned ominous as well. -
Rob Honeycutt at 09:00 AM on 21 April 2012Why Are We Sure We're Right? #1
Steve Case @ 33.... There are several dozen studies that show this to be the case. See IPCC AR4 WG1 chapter 8.6. In general, you'd have a really hard time explaining glacial-interglacials without feedbacks, along with a host of other things, through which climate sensitivity is measured. -
danielc at 08:40 AM on 21 April 2012Why Are We Sure We're Right? #1
@ Noel #32: The consequences of inaction = not having a fridge. Result, spoiled food. The consequences of ordering a fridge that is too large = dealing with the problem while eating fresh and properly cooled food. One consequence is annoying, but tenable... the other is potentially deadly. On climate: the consequences of mitigating emissions and the atmosphere may be expensive, however the side benefits: cleaner power sources, alternative energy technologies, innovation and the creation and burgeoning of potentially huge markets may well offset any short term annoyances. The consequences of doing nothing are by most measures serious, by many measures dangerous, and by some measures, potentially catastrophic. -
Steve Case at 08:26 AM on 21 April 2012Why Are We Sure We're Right? #1
Glenn's list is a good one for the basics of the greenhouse effect, but I should like to know if he's sure he's right about the positive feed backs that elevate CO2 Climate Sensitivity from the basic 1.2°C to 3°C or more. -
William Haas at 08:25 AM on 21 April 2012Shakun et al. Clarify the CO2-Temperature Lag
I again appoligize for my late responses. I will try to answer the posts that involve my comments but I will do that in numerical order. 88 Michael Whitmore Relatively long term average amounts of H2O in the atmosphere scales with increases in temperature. According to green house gas theory, the increase in water vapor traps more heat which also adds to warming. I am sure that the effect has a stable step response or the earth would have burned up ages ago since we are a water planet. H2O levels react to local temperatures in the short term while natural CO2 levels do not. Natural CO2 levels appear to scale primarily with the heating of large volumes of sea water. During the time period that I have been talking about, acording to the article, global temperatures increased but CO2 did not and according to the article, the situation was triggered by Milankovitch cycles. Levels of H2O always vary in the atmosphere but it is the average values that we are talking about that effect climate. Over most of the earth H2O that leaves the atmosphere is quickly replaced except for water starved locations to include deserts and very cold areas of which there were probably more water starved areas of the earth at the time I am refering to than there are now. Prevailing winds also effect the situation. I do not know what actually caused the warming in the far north. Right now I am talking only the 2,500 year period after the LGM. I was initially wrong about Milankovitch forcing during this period. I apparently had the wrong data and I apologize for that. Looking at the data, it may be that this whole period was really part of the normal ice age varation in climate and that the triggering did not occour until the end of this period. Milankovitch forcing was at a low value and not a high value just before this period. Of course if the northern summers were cooler than usual than southern winters were warmer than ususl and vis versa if we consider Milankovitch forcing to be significant. I think that the seesaw effects are primarily caused by ocean currents. The ocean is a domanant player in all of this. The oceans hold a lot more heat than the atmosphere and they hols it a lot longer. The Oceans work as a giant, nonlinear capacitors. By means of convection ceans can be soaking up heat and or be adding it to the atmosphere and it may not be obvious which is occouring where and at what time. I think that the earth in contact to the ocean's bottom may also add to the oceans's heat capacity. That is why I think that some transfer function analysis may help to increase our understanding of what is really going on. You made a comment about CO2. Considerations of its effects are a primary topic here but a full disscussion is I think beyond the scope of this thread. -
noelfuller at 08:11 AM on 21 April 2012Why Are We Sure We're Right? #1
On uncertainty Dikran Marsupial said "In my opinion, a rational cost-benefit analysis, when all relevant uncertainties are properly taken into account, strongly advocates action to mitigate the effects of AGW, rather than adaption when it is already too late." I would ask a person who raises this matter to use a wooden rule, or a dressmakers tape, to measure a distance, supposed to be a gap in a bench say in which a fridge is to go. I would then ask the subject as to certainty in the measurement. Was it read to the nearest millimeter? Could it be read more precisely? How accurate is the instrument of measurement compared to the internationally agreed standard measure? Has the coefficient of thermal expansion been considered in the result? Would it be wise to order a fridge to exactly fit the measurement? What uncertainty should be allowed for in ordering the fridge? Would you decide not to order a fridge given these uncertainties, or is your measurement good enough to act on? Noel -
noelfuller at 08:05 AM on 21 April 2012Why Are We Sure We're Right? #1
Sphaerica "He either truly doesn't get that simple, irrefutable fact ... or else he does know it, and is posting an argument like that any way ..." You might value this quote from Plato: "... there is simple ignorance, which is the source of lighter offences, and double ignorance, which is accompanied by a conceit of wisdom; and he who is under the influence of the latter fancies that he knows all about matters of which he knows nothing. This second kind of ignorance, when possessed of power and strength, will be held by the legislator to be the source of great and monstrous [crimes], but when attended with weakness, will only result in the errors of children and old men; ..." Athenian stranger - Plato, Book of Laws, Book IX Translated by Benjamin Jowett Noel -
JimF at 08:03 AM on 21 April 2012Why Are We Sure We're Right? #1
Well, this whole article depresses me. I'm not a scientist, but I have been active trying to get local pols to finally react to the danger we are facing. But on this post, this is kind of what we get: "I don't think we are sure that we are right..." "Right about what?" "Let people decide if they want to do anything..." "I haven't made up my mind (we have to do anything about it.." That's it? The skeptic side through the Limbaugh's and climatedepot's of the world say definitively that AGW is a HOAX, that scientists who believe it are lying, and that climatology is bought off. Not a lot of equivocation there! And we are expected to go to battle with "I haven't made up my mind yet...?" Yikes. No wonder more and more people in this country don't accept the reality of AGW. -
noelfuller at 07:53 AM on 21 April 2012Why Are We Sure We're Right? #1
from Ari Jokimäki: "I'm on the side that doesn't want to believe anything and thinks that research results should tell us what's happening and possibly what to do about it, if there is such a need." I compare the above with the following: "I taught you not to believe merely because you have heard, but when you believed of your consciousness, to act accordingly and abundantly." - the buddha Gautama The big problem with understanding climate beyond awareness of seasons, and differences while travelling, distinguishing it from weather, is that we are not personally conscious of climate at any large scale. Yet science extends our senses. Science, as in climate science cultivates a form of group consciousness. By it we may "believe of our consciousness" and hopefully "act accordingly and abundantly" Noel -
scaddenp at 07:32 AM on 21 April 2012Why Are We Sure We're Right? #1
"The point of view that John took in the book was that one party was absolutely right and trying to convince the unconvinced to the truth of what that right notion was" TOP, I think is more the point that most of what "skeptics" produce is absolutely wrong. If this was a real scientific debate (with peer-reviewed paper supporting multiple viewpoints), then you would have a valid point. The real science is hardly ever debated. -
climatehawk1 at 07:10 AM on 21 April 2012Why Are We Sure We're Right? #1
Quark Soup has an interesting thread on this topic today. It's about conversations with Dyson and Happer on the basis for their dissent. -
Rob Honeycutt at 07:04 AM on 21 April 2012Why Are We Sure We're Right? #1
William @ 22... Greenhouse theory happens to date back 100 years earlier than does plate tectonics. Greenhouse theory explains a whole lot of things we see including glacial-interglacial cycles and snowball Earth events. AGW is merely an extension of that saying that if WE add the CO2 into the atmosphere (instead of it happening naturally) then we should see similar and proportionate responses in our climate. If you take away greenhouse theory you're left with a whole lot that just can't be explained any other way. -
mattho at 07:04 AM on 21 April 2012Why Are We Sure We're Right? #1
A very relevant debate! There is however one fault on both sides: We often confuse denial with skepticism thinking they mean the same. Most people mean by: I am a Climate Change skeptic that they don't think it's happening, or not human made and/or not bad in any way. However skeptic really means to be seeking truth, and not - as most fake experts do - assume they already found it. This is well presented in the recent book: CLIMATE CHANGE DENIAL by H. Washington & J. Cook (2011) -
danielc at 07:02 AM on 21 April 2012Why Are We Sure We're Right? #1
Repeatable observations. Period. Full stop. I've never met any of you, but I have access to a mass spectrometer, I know how to use it, and I know the implications of measured values and changes and trends in 18O and 16O, 13C and 14C, Hydrogen and Deuterium...and so on... I can measure them myself. I can do the physics myself. I can repeat the experiments and observations in the classic papers from 150 years ago on forward, and as if by magic, I get the same results they do!! WOW!! "Consensus" is different from "Scientific Consensus" - "consensus" means we all agree that the Red Sox are the best baseball team and the color green is far superior... Scientific consensus means that we all can measure similar things, get similar data, show similar trends and that 2+2 = 4. I know that humans are contributing to atmospheric carbon because I can measure the relative proportions of isotopes of carbon through recent and geologic time... I can measure the change in 13Carbon, and the drop in 14Carbon as older light carbon is added via fossil fuel burning. I know that 18O is heavier and is preferentially left behind on evaporation and preferentially deposited during the initial rain-outs. That the ice in glaciers is enriched in 16O... that the Oxygen that critters make their shells from reflects the isotopic composition of the extant water they live (and die) in. That their shells therefore reflect changes in 18O/16O ratio, which is a function of the ratio between evaporation, rain-out and glacier melt over space and time. I can state those as observations, and whether you know me or not, like me or not, think me a complete wanker who stupidly likes the red sox and the color green... you can measure the same thing... and if we're both competent and honest, we will come up with remarkably, magically similar curves through time. -
Why Are We Sure We're Right? #1
william - "Let's say, for the sake of the argument, that all the scientists are wrong. It has happened before." And every time that has happened, it is because a different theory explained the data better than the previous one. When plate tectonics was proposed based on continental edge matching, the theory lacked a mechanism. Only when a mechanism (movement of magma, continents floating on that substrate) was proposed did plate tectonics become a viable theory, one that explained those edge matches without arm-waving. The 'skeptics' appear to be sadly lacking in any such theory. There are lots of half-backed hypotheses through around, most of which are mutually contradictory, and none of which explain the data better than our current physical understanding. In fact, most require ignoring the majority of the evidence - because these hypotheses are incompatible with observations. Glenn Tamblyns list is an excellent start on the range of observations and theoretic domains that new hypotheses must be compatible with. In the meantime, given the quality of the hypotheses thrown around by the 'skeptics', I am reminded of a particular quote: "At times one remains faithful to a cause only because its opponents do not cease to be insipid." - F. Nietzsche -
william5331 at 05:52 AM on 21 April 2012Why Are We Sure We're Right? #1
Let's say, for the sake of the argument, that all the scientists are wrong. It has happened before. As recently as when I took Geology 101 in the 1959, my Geology professor, the head of the department, said that plate tectonics was nonsense. So what other reasons are there for slashing our use of fossil fuel. http://mtkass.blogspot.co.nz/2010/10/forget-climate-change.html -
Bob Lacatena at 04:31 AM on 21 April 2012Murry Salby finds CO2 rise is natural
11, Dikran, Exactly. But what's even better in this case is that you've got simple, raw physics to fall back on (expected solubility change of CO2 by measured temperature). You can compute the variation you would expect in the atmosphere based purely on the ocean temperature and partial pressure of CO2. If you can find an adequate data source and guestimation, you can also adjust that changes in foliage/plant growth. Do that and you'd be left with this clear, unwavering linear trend. And absolutely no further information on where it came from. That is I guess my big problem with Salby... when he identifies the trend he assumes that it must be natural because *insert mumbled, incoherent reasoning here*. And yet what he says clearly says absolutely nothing about the cause of the increase, only the cause of the irregular variation. -
Dikran Marsupial at 03:34 AM on 21 April 2012Why Are We Sure We're Right? #1
David Hume established that causal relationships cannot be proven by empirical means. That is as true today as when he said it, and his aphorism about the treatment of evidence is equally correct today a it was then. So Hume wrote things that appear naive from today's perspective? Lets not throw the baby out with the bath water! ;o) -
TonyLo at 03:23 AM on 21 April 2012Why Are We Sure We're Right? #1
Glenn Tamblyn has it right. Confirmation of our understanding of complex systems is based not on one empirical finding but on many different findings that are consistent or at least have not found to be mutually inconsistent--a kind of triangulation. So, anyone who rejects AGW must present an explanation that offers alternatives to well-established physics and chemistry--something that you never see from the deniers. Marsupial's comments are okay but for heaven's sake do not cite David Hume, the causality denier, in support of science or scientific thinking. -
Dikran Marsupial at 03:19 AM on 21 April 2012Murry Salby finds CO2 rise is natural
@spherica estimating the sensitivity of natural changes in CO2 to changes in temperature is a worthwhile question, but the answer is only 8-9ppmv per degree centigrade. Salby is essentially making the same mistake as Spencer in noticing that there is a correlation between temperature and the annual change in atmospheric CO2. However if you differentiate a long term trend (to get the annual change) any linear increase becomes a constant, and the correllation only explains the variability around this offset, it doesn't explain the offset itself, and hence doesn't explain the long term increase in CO2. I really hope Prof. Salby withdraws the paper (I have sent him an email pointing out this error) his other work is apparently very good and it would be a pity for him to tarnish his reputation. -
Bob Lacatena at 02:47 AM on 21 April 2012Murry Salby finds CO2 rise is natural
Stephen, I think the single biggest nail in this whole coffin is that human emissions have extracted 337 Gt of carbon from the ground and turned it into CO2. So any "natural source" argument must both (a) come up with a comparable source of carbon (which would be utterly huge, and unheard of in the past 800,000 years where atmospheric levels have never topped 300 ppm) and (b) a sink to absorb and completely hide the human emissions. As well as some rationale which explains why the sink works on human emissions but not natural emissions, so that the atmospheric and ocean CO2 increases are "entirely natural" while human emissions magically disappear into thin air and have no effect on anything. This, to me is complete and total denial in a nutshell. To make this sort of twisted, impossible, Alice-in-Wonderland argument work requires such a Lewis-Carrollian pretzel that it clearly demonstrates a mind in utter and complete denial of reality. -
sidd at 02:43 AM on 21 April 2012Why Are We Sure We're Right? #1
1) What am I sure about? Simply put, I am sure that adding fossil CO2 to the atmosphere will warm the surface and I agree with the IPCC confidence limits on Charney sensitivity. 2) Why am I sure ? Because I have the math and physics background to understand the argument and the calculations. 3) What would it take to change my mind ? Some process would have to be discovered that masks the warming effect we expect from releasing fossil CO2, together with another process which causes the same amount of warming that we expect from releasing fossil CO2. I am reminded of "Through the Looking Glass" "But I was thinking of a plan to dye my whiskers green, And always use so large a fan, that they could not bee seen" 4) I am certain enough of 1) that I personally waste no time at all on trying to find mechanisms for 3) sidd -
Bob Lacatena at 02:42 AM on 21 April 2012Murry Salby finds CO2 rise is natural
Dikran, Actually I think he goes further wrong in the step before that, starting at 20:00. He says:… sensitivity… how much net emission of co2 is increased by an increase in temperature, or soil moisture. Because they are incoherent with human activity, they can only represent emission from natural sources. If you know that component from net emission, you can add it from one year, to the next year, and so forth. The total then represents the contribution to the observed CO2 from natural sources.
His flaw is that he sees that changes in temperature correlate well with changes in CO2, as we all know they do and thoroughly expect (due to changes in solubility of the oceans). But he then conflates that well understood and even quantifiable mechanism with the idea that therefore any other mechanism (human emissions) is mere noise, and that therefore the obvious, visible effect must be the cause of the net increase. Interestingly, this presumes some magical source of carbon that he not only fails to identify, but never even attempts to mention or address. This is exactly equivalent to noting that clear skies and clouds cause the largest daily changes in temperature, and therefore the net increase in temperature as the seasons change from winter to summer must be entirely a result of the cumulative, net change from cloud cover but not from the change in the angle of incidence of sunlight over many months (because that net daily increment is small, and "is not coherent" with daily temperature changes). I hope in his paper he takes the time to do some real science, i.e. to compute the changes in partial pressure and solubility in the ocean and atmosphere for each year, to compute the expected change in CO2 from these levels, and then to make some effort to identify the source of the discrepancy. Gee, I wonder what it could be? -
Stephen Baines at 02:40 AM on 21 April 2012Murry Salby finds CO2 rise is natural
Beside the mass balance and stable isotope arguments, there is the fact that ocean pH is decreasing and pCO2 in the ocean is increasing in the surface mixed layer. If increasing temperature were causing the observed atmospheric CO2 increase by outgassing, you would see the opposite. Faced with that, he should have been, at the very least, motivated to try to find an alternative intrepretation for his observations. ` -
Dikran Marsupial at 02:04 AM on 21 April 2012Murry Salby finds CO2 rise is natural
You can see Prof. Salby's talk here and I would strongly recommend anyone interested in the topic to watch it. The key error is introduced in the slide at 21:08; more or less every scientific point prior to that appears essentially correct, but completely uncontraversial. @Sascha Tavere, the uptake of CO2 by the oceans is dependent on temperature, but also by the difference in partial pressure between the surface ocean and the atmosphere. The equilibrium warming due to CO2 increases only logarithmically, but the pressure relationship is IIRC linear, and opposes the change. I suspect this is the feedback that Salby had in mind, but I don't know why he didin't just say so. -
Bob Lacatena at 01:57 AM on 21 April 2012Why Are We Sure We're Right? #1
Dana, See, that's my problem. The more strategically minded deniers seem to have adopted the strategy that they can take and dismiss one, single, ridiculous position that is supported only by the nut-jobs of the world (the slayers), i.e. that the GHG effect violates the laws of physics. By so doing, they try to imply that they are the center, the denial nut-jobs are on one fringe, and the entire rest of the professional climate science community represents the other fringe. But they also continue to accept other utterly simple and easily refuted arguments, specifically whether or not the globe is warming (Watts on BEST, Spencer with his recent UHI analysis, Curry with too short a trend) and also -- and this is really, really just downright laughable -- the source of increased carbon dioxide in the atmosphere. I mean, really... the CO2 arguments are just so basic and simplistic that anyone who tries to go there should have a giant D (let's be nice and say that's for "dunce") branded on their heads... particularly if they are "excellent" scientists like Salby or Curry. Even Singer refutes the "natural CO2" argument in "Climate Deniers Are Giving Us Skeptics a Bad Name." I think it's time for scientists who are literally embarrassing the field to be publicly embarrassed themselves. I mean, it's almost a little too easy for me to accept that I'm right when the most "professional" and "excellent" scientists that are in denial are putting forward insanely stupid arguments (Salby on the source of CO2, Curry on Salby revolutionizing climate science, Spencer on surface UHI when his own work demonstrates the opposite in the troposphere). Why are we sure we're right? Because the deniers invest so much energy into coming up with things that are laughably wrong. -
Dikran Marsupial at 01:30 AM on 21 April 2012Why Are We Sure We're Right? #1
Like Dana, I am disspointed to hear that he has not reconsidered. Sadly it seems he will be ruining an otherwise excellent academic career (see his publication record). Unfortunatly once someone has an incorrect idea in their heads it can be difficult for them to accept that they are wrong, counterintuitively especially of the proof happens to be very simple. I suspect being a genuine expert in one field makes one particularly prone to this (c.f. Dyson). If Salby's paper appears in a decent journal, there will be comments submitted, even if I have to do write it (again! ;o). I did post Salby a pre-print of my Energy and Fuels paper, but recieved no reply. -
Uncle Ben at 01:15 AM on 21 April 2012Roy Spencer finds negative feedback
DSL: " The point is that you can indeed calculate sensitivity in a complex system; you just can't calculate it with the precision of a closed mathematical system." I agree! In fact, Spencer has provided us a way to improve the estimate of sensitivity. By separating the trajectory of dH/dt vs dT into segments in which the effect of dH/dt and the non-radiative forcing that creates clouds in the absence of strong dH/dt, he has been able to estimate the slope of the regression of the latter. He finds that the slope is about 6 in the usual units, as opposed to 2.5 using the combined data. This yields a sensitivity low enough to show that the feedback from dH/dt causes is negative. Doubling CO2 then is seen to cause only 0.5 deg. C of warming. Not much calculation is needed, in fact. If you take the trouble to look at his plots, you will see that the straight-line segmenmts are numerous, parallel, and obvious. It is quite convincing. It is their slope which gives the sensitivity to dH/dt. The plots are so clear in showing the straight-line segments that the precision is much higher than that of the widely scattered estimates of sensitivity found by other means. We know now why they are widely scattered. A variable has hitherto been ignored. -
dana1981 at 01:06 AM on 21 April 2012Why Are We Sure We're Right? #1
Sphaerica @9 - to be fair, Watts has joined Singer and Spencer et al. in denouncing the 'sky dragon' hardcore deniers. That said, Watts seems to embrace virtually any other "it's not humans" argument on his blog, Salby's nonsense being the latest in an incrediby long line of ludicrous examples. But at least he did draw the line somewhere! Tom @14 - that's disappointing. After not hearing a word from Salby in 8 months I was hoping like Dikran @13 that he had come to his senses. Given his comments on Spencer and Braswell, clearly that's not going to happen. TOP @11 - I'm sure John would say the point of the handbook is that although we can't be certain, the scientific evidence does overwhelmingly support AGW, and that's what we need to communicate to people. -
Bob Lacatena at 00:59 AM on 21 April 2012Why Are We Sure We're Right? #1
13, Dikran,I gather he is an excellent scientist...
I find this utterly impossible to accept. The concept that small variations can overwhelm a consistent but important underlying signal (i.e. natural variations paralleling global temperature swings versus regular, cumulative addition through human emissions) is literally the simplest thing in the world to grasp. No reputable scientist could possibly make that sort of mistake, and then trumpet it in public as an upcoming, landmark paper. At the same time, his failure to explain or even address where human emissions might have gone (if not into the atmosphere and ocean) as well as where the actual increase could come from (given that CO2 has never risen above 300 ppm in the past 800,000 years) is quite simply unacceptable. His argument amounts to the same denial argument with regard to temperature... an inability to distinguish a trend from the noise. This is basic, basic, basic. He demonstrates either willful ignorance or complete incompetence. In either case, "excellent" cannot come anywhere into this equation. -
Tom Curtis at 00:57 AM on 21 April 2012Why Are We Sure We're Right? #1
Dikran Marsupial @13, apparently this was Prof Salby's position on Feb 20th:"Dear Brian, Apologies for the belated reply; we’re on summer break here. The technical paper underpinning my presentation to the Sydney Institute has certainly not been withdrawn. The cycle of scientific publication is slow, typically about a year. For a subject as political as this one, it can be very slow. The fiasco surrounding Spencer and Braswell (2011), a thinly-veiled exercise in coercion, didn’t help. But, with patience, we will eventually get there. Upon formal release, a notice will be sent to the numerous interested parties. In the meantime, a couple of matters of possible interest: (1) About half of the material in the Sydney Institute presentation is developed in Physics of the Atmosphere & Climate, a peer-reviewed volume that is now out. Although developed for a technical audience, elements should be comprehensible to the non-specialist. Highlighted in the attached is material of relevance. (2) In the coming weeks, a video of the presentation will be made available through the Sydney Institute – inclusive of full graphics. Stay tuned. Murry Salby"
So apparently, no he has not seen reason. But any difficulty he has with publishing is purely to do with politics and nothing to do with any flaws in the paper /sarc -
dana1981 at 00:46 AM on 21 April 2012Global Surface Warming Since 1995
Sphaerica @9 is correct. If only considering temperature data, as with Santer and Jones in the first part of the inteview, the question is simply whether the average global temperature has increased. Attribution of that warming, while an important question of course (one which I've explored in many SkS posts), is a different subject which requires more information. -
Dikran Marsupial at 00:28 AM on 21 April 2012Why Are We Sure We're Right? #1
To be fair to Prof. Salby, I gather he is an excellent scientist, it is just that he has made a serious error on this particular point. I suspect that the journal paper that was mentioned at the time has been quietly withdrawn by Prof. Salby after having seen that the various counter-arguments following his presentation are entirly correct. -
Sascha Tavere at 00:19 AM on 21 April 2012Murry Salby finds CO2 rise is natural
@ Dikran Marsupial Re Q&A Audience question: "... more temperature -> more co2 -> more temperature? ..." (4'30") Murry Salby: "For reasons that I am not going to go into with this audience, there has to be a negative-feed back that bridles this positive feed-back and holds things in check." Oh yeah? Do tell more professor Salby! He didn't. There just "has to be". Am I offended because of the condescension? It might not be possible when speaking to lay people to explain everything in a short space of time, but it seems to be a crucial point that you can't hedge on if you're serieus. Pique or scepsis? -
DSL at 00:14 AM on 21 April 2012Roy Spencer finds negative feedback
Uncle Ben: "3. The little model demonstrates a mathematical fact, which is already obvious to students of statistics, namely that you cannot compute the sensitivity to one variable if another hidden variable is varying the output." Welcome to the geophysical sciences. I hope you had a nice stay in the math department. Every day, you manage to make decisions based on intuitive modeling where one or more variables are unknown. You've managed to live, so far. You've probably actually learned from this daily type of intuitive modeling. You've probably made important decisions based on weather forecasts, which use the same type of modeling. The point is that you can indeed calculate sensitivity in a complex system; you just can't calculate it with the precision of a closed mathematical system. Roy knows that. You should know it. And the unknown variable in this case is not all that unknown. I'll wager that you yourself won't accept certain values for it. -
Bob Lacatena at 00:12 AM on 21 April 2012Global Surface Warming Since 1995
7, Slioch, No. Santer is only discussing whether or not it has warmed, but from the frame of reference that if there were anthropogenic warming then you would have to have 17 years to see any warming (natural or anthropogenic). Santer is not discussing attribution of that warming, and neither is Phil Jones with his "statistically significant" response, and neither is this post. If you wish to discuss it, please do so on the "It's not us" thread here. Your inclusion of Phil Jones' answer to a later question about attribution and your (mis)interpretation of Foster and Rahmstorf (2011) inappropriately steer the discussion in that direction. No one is saying that it's not an interesting or important question. Only that this isn't the place to discuss it. This thread is about Santer and whether or not the earth has warmed in the past X years.
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