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Clouds provide negative feedback
RW1 My point is there is really no physical or logical reason why the net cloud feedback would suddenly switch from negative (cooling) to positive (warming) on the next few watts incident on the surface It doesn't need to switch to a net positive effect in order to be a positive feedback. If the total effect is currently negative, and a warmer climate causes structural changes in cloud cover that makes the total effect less negative, then that will result in additional warming beyond the original forcing. In other words less cooling is equivalent to warming. -
mdenison at 11:00 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
Having read the article quoting Lindzen it seems to me that Lindzen is mostly concerned with the measured rise being comparable with the magnitude of natural variability. I think Dana has misinterpreted Lindzen's comments. He was not trying to claim that the temperature rise was 0.1C but rather that the effect excluding natural variation was only 0.1C since noise renders it pretty much impossible to detect a meaningful signal. "As far as the data goes, I would argue that we really don't have the basis for saying it's a half degree plus or minus 0.2. That is false use of science. What we have is data that says that maybe it occurs, but it's within the noise." When we compare 1880 decade with average temperatures of the next 100 years we see that it is below average but not so far below as to make us believe it could not have dropped to this level by natural variability. In other words the 1880's are colder than the norm, ie. in Lindzen's anomalous minimum. Likewise we see that the 1970's are above average but again no more than can be explained by than magnitude of natural variation. In other words he believes that most of the warming is explained by chance switch from an unlikely cold state to an unlikely warm state. It is just unfortunate that the GISS record happens to begin and end on these extremes. Therefore we must attribute most of the surface temperature rise to natural noisy redistribution of heat and only a small amount 0.1C could be due to heat input to the system and even that estimate is very uncertain. He states "Even if the Sun's output were fixed, even if the radiative input were absolutely constant, even if there were no change in the absorbing gases, the ocean itself can take up and store heat and release it..." and later he states "On the planet the most wonderful constituent is water with its remarkable thermodynamic properties. It's the obvious candidate for the thermostat of our system, ...." The real problem for Lindzen in 1989 is natural variability. The oceans an clouds are clearly important but are poorly understood. Greenhouse warming may be occurring but he feels that given the size of observed effects natural variation is the more important given the amount of noise it creates. He believes the noise is clearly drowning the signal of CO2 induced warming and therefore CO2 warming must be small and will remain of little significance. "I argue that the greenhouse effect does not seem to be as significant as suggested." He was wrong. There was a signal and it was indicating a rising CO2 effect. Jim Hansen spotted it despite the noise. "The predicted CO2 warming rises out of the 1sigma noise level in the 1980s and the 2sigma noise level in the 1990s" In 1989 Lindzen had some excuses. There was less data and it was noisy. By 1981 a good deal of the temperature rise was natural or at least not due to CO2 and much was masked by poorly understood aerosols. 23 years later he still appears to be clinging to this position that natural variation in the oceans and/or clouds can explain the warming even though no one has yet made a case that indicates this is possible. And this despite the fact that the signal is well out of the noise of natural variability and consistent with the warming expected due to greenhouse gases. It would appear that no matter how high temperatures rise this is, for him, an indicator that natural variability is ever greater than we had supposed. -
RW1 at 10:40 AM on 29 April 2011Clouds provide negative feedback
Sphaerica (RE: 156), "But there is. You're just denying that it exists. Hint: Go to the top of this web page and actually read the post." I have read the post. I do not see where the issues I've raised has been addressed or answered. -
David Huber at 09:53 AM on 29 April 2011Climate Change Denial book now available!
My next book purchase. Thanks John! -
Ken Lambert at 09:45 AM on 29 April 2011How climate change deniers led me to set up Skeptical Science website
Daniel Bailey Thats the point Daniel - I was not shown to be 'in error' on the Flanner thread - quite the reverse. The main respondent Tom Curtis made error after error and had to admit such while ploughing on to the next calculation, which eventually got closer to the Trenberth number. You have to remember that Dr Trenberth is a proponent of AGW - just one of the leaders in the field who we rely upon for the numbers. When your AGW enthusiasts are making uncorrected extreme claims of warming which bear no relation to scientists like Dr Trenberth's numbers - then it is time to say that this site has lost its scientific mojo. John Cook is also seeming slow about getting Dr Trenberth on to this site. Do you fear a couple of skeptical science interactions with Dr Trenberth John?Moderator Response: [e] Tom Curtis currently has the last comment on the Flanner thread addressing your claims. Please take any further discussion over there where it belongs. -
michael sweet at 09:34 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
Dana, Terrific post. Are there records for Spencer and Christy for a comparable post for them? I think all three of them claimed that the satelite record was better than the surface record. That has been proved incorrect. The skeptics like to say Hansen's predictions are bad becasue they are not exactly correct. By comparing Hansen to the skeptics it becomes clear who has been more accurate over time. -
Marcus at 09:34 AM on 29 April 2011CO2 is plant food? If only it were so simple
"you seem to intimate that root-pathogens, insect pests and other diseases are going to emerge as new problems" @John D. No, what I'm intimating is that these are going to become even *more* dominant problems in an enriched CO2 world-a fact backed up by at least one FACE trial in each of the 3 cases (insect pests, weeds & soil-borne diseases). Even assuming we can overcome these problems quickly enough, it will only be done at a significant increase in the cost of farming-a cost which will be passed on to the consumer. Also, given that the upbeat assessment for yield increases you cite actually seem to all come from just the *one* 3-year FACE trial (Meta-analysis of FACE trials over the last 15 years-most of which were performed under otherwise ideal conditions-shows only a 5-7% yield increase in rice and and 8% yield increase in wheat), I find it slightly hypocritical that you easily dismiss the results of FACE trials which highlight the *downsides* of an enriched CO2 world. Still, I've noticed you've got a habit of cherry-picking only the stuff that supports your claims, whilst ignoring anything which undermines it. -
Marcus at 09:26 AM on 29 April 2011CO2 is plant food? If only it were so simple
@Arkadiusz Semczyszak. I see you're being true to form-another long winded post that essentially says *nothing*. "We should also remember that the increase in CO2 usually: - increases the number of leaves and flowers," Actually, CO2 usually increases the vegetative biomass (stems & leaves)-at the *expense* of reproductive biomass (fruits & seeds). Unless you intend to start eating leaves & stems in the near future, I'd suggest that's *not* a good thing. Also, as those leaves will contain less Nitrogen-a major component of the chlorophyll in those leaves-then I'd suggest that this will lead to a decline in total photosynthesis-again in contradiction to the claim that "CO2 is a plant food". "The current "mechanisms" of photosynthesis exist hundreds of millions of years. C4 grasses arose as a reaction to the unusual - in the history of life on Earth - a decrease in the concentration of CO2 - just a 3? million years ago ..." Yes, & guess which kinds of plants are the most dominant in agricultural terms? That's right, the grasses which first evolved 3 million years ago under a "low" CO2 regime. Rice, Wheat, Barley....amongst other "grass-based" crop plants. Again, sort of defeats your argument, doesn't it? "Being (in my country) at an scientific conference on pests - warming - I heard that you get from us (as a result of global warming), The Western Corn Rootworm, Diabrotica virgifera ... I have a question - that the yields and profitability of maize production is higher in my country, or where there is a Western Corn Rootworm ?" ....and what exactly are you trying to even say here? It sounds like a pretty weak attempt to avoid the issue if you ask me. "Consequently, adequate data are not available to reliably estimate the extent to which amelioration of drought stress at elevated [CO2] will improve yields over the range of C4 crop growing conditions and genotypes." Even if this were the case, & I've seen plenty of evidence to the contrary, then at best it simply proves the fact that claims that "CO2 is plant food" is not only overly simplistic, its also extremely premature. -
robert way at 08:40 AM on 29 April 2011Climate Change Denial book now available!
Congrats John, You will be remembered as one of the real heroes in this great fight -
johnd at 08:38 AM on 29 April 2011CO2 is plant food? If only it were so simple
Ian Forrester at 00:41 AM, in the context of the paper you referenced, referring to any differences as being CO2 induced is a means of differentiating the results from the control results. However until the grain and flour properties of the higher yield/ lower protein grains are compared head on head with grains with the same higher yields/ lower protein characteristics grown under non CO2 enriched conditions, then it is not possible to establish whether the differences are merely growth related, or if there is in fact some direct biological link to CO2. Bear in mind that the FACE and laboratory studies are relatively narrow focused, and without the much longer and broader database that has been accumulated by the grain growing and flour milling industries that has seen virtually every combination of factors, apart from CO2, that are possible. The qualities that the paper you referenced focused on as being important, were developed by the industries themselves through the accumulation of knowledge as commercial interests sought to refine the quality and productivity of both the end and the primary products. The battle between yield and protein, and the relevance of nitrogen, is, and has been long and well understood by every grower from even before nitrogen based fertilisers began to be used, and from whom much of the existing knowledge has originated. -
dorlomin at 08:31 AM on 29 April 2011How climate change deniers led me to set up Skeptical Science website
Keep em coming John, great blog gets put to near daily use on the Guardians enviroment pages. Great to see so many people from other parts of the world keen to stand tall and explain a science others are hell bent on smearing. I think you have done a fantastic job with where you are pitching the blog in terms of both tone (its very easy to get dragged into the name calling and by hell I am guilty of that) but also being so well aimed at people who may not have strong science backgrounds but are smart enough to pick it up. Its easy for a professional to knock out a very nerdy and science dense technical blog posting and its easy to knock out blogs about the social or political aspects of climate science but you manage to put together one that is about the technical aspects but that the man "on the Clapham omnibus" can understand. Hats off. -
CO2 effect is saturated
Berényi, Moderators (Emphasis as in originals) KR: "- Most importantly; Anderson's spectra are not corrected for global warming, to the equivalent black body temperatures. Anderson is showing the raw differences between the two satellite spectra with some fairly impressive corrections added. But this is not corrected for the equivalent black-body spectra (Brightness Temperature) as Harries did, and hence does not show what you claim it does." (hence overlaying these two different graphs is incorrect) Berényi: "You are right. However, I would use a different wording: Anderson's spectra are not adjusted until they confess. The reason I am saying that is because Harries at al. do not simply correct for equivalent black body temperatures, they perform a vastly more sophisticated transformation." -- Confess? What does Anderson have to confess to? Having written a rather clear paper on comparing data from two different platforms, that you have misinterpreted? Moderators, I think this is going entirely too far. These constant unjustified insinuations and accusations of bad science and data manipulation are clearly outside the Comments Policy limits. Berényi, unless you have proof of malfeasance, I would suggest you drop the accusations. If you disagree with a paper, point out the issue you disagree with. But attributing bad practice and data manufacture (as you have done at least twice in this thread alone) is a completely unjustified, insulting, and repetitive ad hominem fallacy.Moderator Response: [DB] Agreed. This goes no farther without links to proof of malfeasance. No more insinuations, no more implications. Further remarks not complying with the Comments Policy will be simply deleted. -
littlerobbergirl at 07:25 AM on 29 April 2011CO2 is plant food? If only it were so simple
great post Dawei. but, oh dear, wot adelady says in 23. it's all wiped out by other factors. grown women weeping here at unseasonal infestations of various bugs, despite best efforts of carefully encouraged wild life, slow worms, toads, and even the final solution - blitzing with chickens! a month of drought at a time of normally wet weather can undo any advantage of raised co2 levels. -
littlerobbergirl at 07:15 AM on 29 April 2011Wakening the Kraken
'the kraken wakes' comes to me from wyndham's science fiction - so i'm a pleb. well, it wont matter soon... i was on the loo with a back copy of the new scientist just today reading another possible reason for the PETM - massive methane release triggered by a spreading ripple from a pulse of magma - hot blob - from the geologic hotspot at iceland. pay to view but here is the chap proposing the main theory; http://www.esc.cam.ac.uk/people/research-staff/bryan-lovell -
Albatross at 06:51 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
This email sent by Lindzen to denier Anthony Watts speaks volumes about how those in denial and 'skeptics' collaborate and scheme to obfuscate and mislead by cherry picking the data for a predetermined outcome. Scientific misconduct much Dr. Lindzen? "Look at the attached. There has been no warming since 1997 and no statistically significant warming since 1995. Why bother with the arguments about an El Nino anomaly in 1998? (Incidentally, the red fuzz represents the error ‘bars’.) Best wishes, Dick ================================================== Richard S. Lindzen Alfred P. Sloan Professor of Atmospheric Sciences MIT Cambridge, MA 02139 USA” -
BBP at 06:42 AM on 29 April 2011How climate change deniers led me to set up Skeptical Science website
Mark-US There are several things wrong in what 'someone' was saying. 1) The sun will not go nova (a nova is caused by mass transfer from one star to another, so you need at least 2 stars). 2)The sun will become a red giant, but that is billions of years from now. Currently, the suns radius may be changing cyclically, but it is not getting bigger, for example, see Suns Diameter 3) Any radius change will have an effect via a change in apparent luminosity, which is not changing (See It's the sun) -
david b at 06:22 AM on 29 April 2011CO2 is plant food? If only it were so simple
Stephen Just to reiterate/clarify, I would bet on the fact that the long term impact of drought and shifting patterns in precipitation will quickly eclipse any benefits realized by atmospheric CO2 "enrichment." Compare a map of Global Net Primary Production (NPP) to a map of global precipitation patterns you'll see a strong relationship between the two variables. Increased CO2 will hypothetically improve water use efficiency but it is clear that precipitation is, far and away, the leading factor determining primary carbon fixation. -
dana1981 at 06:18 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
pbjamm - the key aspect Lindzen was wrong about was the temp *change* (a.k.a. global warming). You can shift his graph upwards with a different interpretation of his comments, but it's still equally wrong about what matters. He was wrong about both the temp record accuracy and the warming effects of CO2. -
dana1981 at 06:12 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
It's also worth noting that while Lindzen claimed the temp change was -0.2 to +0.4°C, GISTEMP had measured it at 0.5 to 0.7°C. The measurements weren't even within his range of possibilities! -
pbjamm at 06:11 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
We seem to be taking very different things away from his statement that I quoted @10. To me he was saying that 1880 is essentially an unintentional cherrypick. The instrumental record begins then, but it was unusually cold so an unfair starting point. However... He is wrong on that point, "the entire record (Hadley data) indicates that 1880 was pretty average (or a bit above). Perhaps I am being too generous to him since he has a history of 'misstatements' of fact. Even if you were to spot him the 0.2C on the starting point, raising the whole whole graph by that amount, the projection would still be off by a very large margin. -
PeteM at 06:06 AM on 29 April 2011How climate change deniers led me to set up Skeptical Science website
This is an excellent site for those who prefer to use rational thinking and base opinion on the complexities of scientific understanding. I look forward to buying and reading John's book as one of my summer reading pleasures. -
Albatross at 05:54 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
dana81, "it was just as likely that the planet had cooled 0.2°C as warmed 0.4°C!" You are right, of course Dana-- I was trying to give him the best possible benefit of the doubt and in doing so had to force myself to turn a blind eye to that major faux pas by Lindzen. It is truly sad (and scary) that disingenuous people like Lindzen can do no wrong in some peoples' eyes, heck he is even revered by the "skeptics" and those in denial about AGW. -
Irek Zawadzki at 05:47 AM on 29 April 2011How climate change deniers led me to set up Skeptical Science website
Like for most people my interest in the issue of the climate change used to be very limited. I have heard about Al Gore’s movie, read some articles in the popular media and I assumed that the issue by and large was settled. Then one day I had a “vigorous discussion” (if I may borrow John’s expression) via Skype with my brother who bombarded me with a litany of skeptical arguments he picked up from polish newspapers and from TV. I was skeptical about the validity of his arguments but could not immediately answer them. The next day I found skepticalscience.com and it took me about a minute to realize that this is exactly the resource I needed. The only problem was that my brother does not speak English so I asked John for permission to translate some articles to Polish. He immediately picked up on my offer and patiently worked with me on setting up the Polish translation page. I am proud to say that my brother, after reading the “Scientific Guide to Global Warming Skepticism” and other translations, is no longer a “skeptic”. I have reasons to believe that many other people in Poland found John’s website extremely valuable and educational. Thank you John for a true World Treasure! -
dana1981 at 05:39 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
Albatross #12 - according to Lindzen, it was just as likely that the planet had cooled 0.2°C as warmed 0.4°C! #13 - indeed, as another example Lindzen continues to make the demonstrably wrong "Earth hasn't warmed as much as expected" argument, at least since this 1989 talk. He seems to have no qualms continuing to peddle disproven claims for decades on end. Yet he's one of the most highly-revered and referenced scientists by "skeptics" -
Albatross at 05:29 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
Jimbo @9, "If there is one thing that points out the difference between science and anti-science, it is that even though Lindzen has been consistently wrong for at least 20 years." Good point, yes Lindzen has been peddling the same misinformation for decades, and what is perhaps worse, he has not adjusted his position or acknowledged his errors (to my knowledge) when he has been shown to be wrong. That is the very antithesis of good science. -
Albatross at 05:25 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
Pbjamm @10, To this day Lindzen disputes the amount of warming, and makes every effort to downplay the amount of warming and/or caste doubt on the values. For example, when he testified to Congress recently he stated that part of the warming trends because the thermometers are more sensitive to warm perturbations than they are cold ones. The one part I might take issue with in this article is that Lindzen stated a warming of +0.1 with an uncertainty (unsubstantiated) of +/- 0.3 C. Even so, allowing for a warming at the upper end of his range (+0.4 C) by 1988/1989 (not 1981) still does not improve his situation much. The inconsistencies and inadequacy of Lindzen's statements are quite striking. The recent words of wisdom by Dr. Emanuel come to mind (yet again!): "[B]eware those who deride predictive science in its entirety, for they are also making a prediction: that we have nothing to worry about. And above all, do not shoot the messenger, for this is the coward’s way out of openly and honestly confronting the problem." -
Philippe Chantreau at 05:21 AM on 29 April 2011Cosmic ray contribution to global warming negligible
"At issue is the fact that so many other particles can form CCNs that the question was whether or not the additional (GCR generated) ones were significant" That is indeed a big question. Oceanic air, although less rich in CCN than that over land, gets a lot of ions from sea spray, and these tend to be in already big clusters. Useable size for CCN is about 30nm diameter. The particles created by GCRs are about 0.5. This covers some of the processes necessary for CRs to have any effect at all. As you will see, it is rather convoluted. It is far from obvious whether or not it can be a factor at all in either weather or climate. Furthermore, it has been shown already that CCN size is a more important factor than chemistry. -
Stephen Baines at 05:15 AM on 29 April 2011CO2 is plant food? If only it were so simple
david b "... gas exchange analysis of photosynthesis cannot be trusted as it depends on stomatal "openess" to accurately measure the exchange of CO2 and water vapor from the leaf mesophyll and the atmosphere." Gas exchange is certainly problematic if you are studying the short term consequences of water availability on photosynthetic processes. How the the trade off- between CO2 and water economies balance at a physiological level in a world of changing CO2 and climate is a really interesting topic to me. But, I think Bob and I were talking about the influence of a persistent change in local water availability on overall plant growth/biomass/productivity, which is the endpoint of most interest in discussion of the net effect of CO2 and climate change. We don't really need FACE experiments to know water availability makes a difference in regard to vegetative biomass or productivity. The results of large long term natural experiments are there for us to look at right now. I see you answered already...sounds like we're on the same page. -
dana1981 at 05:07 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
pbjamm - either Lindzen thought that 1880 was much hotter than it actually was, or that 1989 was much colder than it actually was. Either way he was wrong, and this point doesn't change the slope of his graph, or the fact that it's 90% lower than reality. -
david b at 04:49 AM on 29 April 2011CO2 is plant food? If only it were so simple
@ Sphaerica - OK, I see what you're getting at. It's a delicate balance between water loss and CO2 aquisition. Nate McDowell et al did an excellent job reviewing drought related mortality in the context of climate change (but not CO2 increases). You'll notice that one of the major hypothesis of (long term) drought mortality is from carbon starvation due to stomatal closure. In this case it is a combination of water and CO2 limiting growth (ultimately resulting in mortality). On a shorter time span drought mortality (most often occurring in herbaceous, non-perennial plants) is due to all out interruptions of cellular processes, transport of nutrients and assimilates and overheating in the leaves leading to a denaturation of enzymes. In this case CO2 levels have zero impact on prolonging plant life. The opposite would be true as well, in well watered situations with limiting CO2, the plant will die (just not as rapidly). It would really require a case-by-case basis to estimate CO2 vs. water status threshold, but the balance and trade-offs between the two would, again, make it difficult to tease apart what the actual cause of mortality would be. Sorry for the +/- non-answer. -
Berényi Péter at 04:47 AM on 29 April 2011CO2 effect is saturated
#158 e at 03:49 AM on 29 April, 2011 Since you are not comparing equivalent data Since you have not read the paper I was talking about -
pbjamm at 04:43 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
dana1981 "The bottom line is that Lindzen claimed the planet only warmed 0.1°C between 1880 and 1989" That is not at all how I read the statements from the article: Nor, he said, was the temperature data collected in a very systematic and uniform way prior to 1880, so comparisons often begin with temperatures around 1880. "The trouble is that the earlier data suggest that one is starting at what probably was an anomalous minimum near 1880. The entire record would more likely be saying that the rise is 0.1 degree plus or minus 0.3 degree." ==== He is (incorrectly) saying that 1880 was abnormally cold and therefor a poor starting point. I don't think he is disputing the temperature in 1981. -
Bob Lacatena at 04:31 AM on 29 April 2011CO2 is plant food? If only it were so simple
48, david b, I was thinking of a more general approach... less in tying precipitation changes to specific biological mechanisms (like photosynthesis), and more along the lines of "it doesn't really matter how good increased CO2 might be for a plant if it dies due to lack of water." -
Mark-US at 04:28 AM on 29 April 2011How climate change deniers led me to set up Skeptical Science website
Awesome work FYI recently someone offered a reason for denial that isn't on your list. This is closely related to the (false) claims that the sun is burning hotter. Instead, we're closer to the sun before. The reasoning went like this: The sun is slowly going nova, and as it does it is slowly turning into a red giant, and that means the sun is expanding, but since the earths orbit is the same, the result is that the sun's surface is now closer to the earth.Moderator Response: [DB] Nice Poe. -
dana1981 at 04:24 AM on 29 April 2011Lindzen Illusion #1: We Should Have Seen More Warming
Ken L - you're equating two totally different concepts. -
david b at 04:23 AM on 29 April 2011CO2 is plant food? If only it were so simple
@ Stephen Baines and Sphaerica Your requests offer a uniquely difficult task to accomplish unfortunately. Most drought studies that involve determinations of photosynthetic responses tend to be unfavorable in a peer reviewed context. For plants there is either enough water or it is limiting. In water limiting conditions most plants close their stomata (completely or almost completely) to limit water loss. The unfortunate side effect of this is that gas exchange analysis of photosynthesis cannot be trusted as it depends on stomatal "openess" to accurately measure the exchange of CO2 and water vapor from the leaf mesophyll and the atmosphere. Long story short - it is very difficult (if not impossible) to tease apart the decrease in actual photosynthesis from instrument error in relation to reduced stomatal conductance in response to drought. More holistic measurements may be taken in drought studies of CO2 enriched plants (biomass, grain yield etc.) but these fail to truly capture the mechanism affecting differences in plant growth and resource allocation that gas exchange captures so well. Chlorophyll fluorometry offers promise in quantifying photosynthesis with out relying on gas exchange, but thus far the responses measured by fluorometers deal more with the efficiency and productivity of photosystem II than with the photosynthetic apparatus as a whole. -
CO2 effect is saturated
Berényi, You are comparing against the wrong Harries graph. The comparable graph showing measured brightness difference is item b in Fig 1., not item c. You will notice it is similar to the other graphs you have provided. Here is the full figure:
And caption:
"a, Observed IRIS and IMG clear sky brightness temperature spectra for the central Pacific (10° N–10° S, 130° W–180° W). b, Top, observed difference spectrum taken from a; middle, simulated central Pacific difference spectrum, displaced by -5 K; bottom, observed difference spectrum for 'near-global' case (60° N–60° S), displaced by –10 K. c, Component of simulated spectrum due to trace-gas changes only. 'Brightness temperature' on the ordinate indicates equivalent blackbody brightness temperature."
Since you are not comparing equivalent data, your analysis and conclusions are moot.
-
Jim Powell at 03:32 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
I appreciate getting credit for pointing out the 1989 interview with Lindzen, but in the interest of full disclosure I must report that I discovered that interview in Hansen's "Storms of My Grandchildren," Appendix 1, "Key Differences with Contrarians." In it, Hansen points out other errors that Lindzen has made in addition to those dana1981 describes above. If there is one thing that points out the difference between science and anti-science, it is that even though Lindzen has been consistently wrong for at least 20 years, his stature among deniers has risen. -
Berényi Péter at 03:31 AM on 29 April 2011CO2 effect is saturated
#155 KR at 08:44 AM on 28 April, 2011 - Most importantly; Anderson's spectra are not corrected for global warming, to the equivalent black body temperatures. You are right. However, I would use a different wording: Anderson's spectra are not adjusted until they confess. The reason I am saying that is because Harries at al. do not simply correct for equivalent black body temperatures, they perform a vastly more sophisticated transformation. Unfortunately there is no open access copy of Harries 2001 online, so I will use a conference abstract by the same authors which discusses their adjustments at some length. 11th Conference on Satellite Meteorology and Oceanography Session 2, Climatology and Long-Term Satellite Studies (Continued) Monday, 15 October 2001, 4:00 PM-5:00 PM 2.2 Changes in the Earth's resolved outgoing longwave radiation field as seen from the IRIS and IMG instruments (Invited Presentation) Helen E. Brindley, P. J. Sagoo, R. J. Bantges & J. E. Harries First of all let's compare their raw difference spectrum with the one given in Anderson 2004.
The match is reasonably good considering Anderson processed many more spectra, attained finer spectral resolution, smaller error bars and also covers a larger area.
And Brindley et al. show even less decrease in brightness temperature in the CO2 wing (at the left edge) than Anderson et al. do. Practically none at all, while both analyses show increase in the window and decrease in the methane band (the curve is above or below zero, respectively).
So. How does Fig. 1. Harries 2001 come about?
It is the difference between the spectrum above and a theoretical spectrum where radiative effects of changes in water vapor distribution along with sea surface and atmospheric temperatures are taken into account, but GHG concentrations (other than H2O, and only for radiance calculation purposes) are kept constant.
Therefore their finding is not "direct experimental evidence" in any reasonable sense of the word. It can't be better than their theoretically derived spectrum used for adjustment.
I quote the full passage dealing with this theoretical derivation from the extended abstract, because it is essential.
"3. SIMULATION METHODOLOGY
Pentad mean global temperatures and specific humidity fields representative of two twenty-seven month intervals centred on the operational periods of the two instruments, running from April 1969 to June 1971, and April 1996 to June 1998 were generated using the HadleyCentre Atmospheric Model version 3 (HADAM3).
HADAM3 comprises the atmospheric portion of the Hadley Centre Coupled Climate Model, with 19 levels in the vertical, and a horizontal resolution of 2.5° latitude x 3.75° longitude.
The model was forced by observed sea surface temperatures taken from the Global Sea Ice and Sea Surface Temperature (GISST) data set, and also included the effects of changes in trace gases, and a parameterisation of volcanic and solar forcing over the period considered. In order to quantify the impact of model uncertainties, four realizations of the atmospheric state were provided.
Using the model geophysical fields along with representative values of trace gas concentrations for each period, radiance spectra were calculated for each grid point and month at 1 cm-1 resolution over the wavenumber range 600-1400 cm-1 by the MODTRAN3.7 radiative transfer code. These 1 cm-1 radiances were then degraded to 2.8 cm-1 resolution using the IRIS instrument function and converted to the equivalent BT".
The take home message is they have used various data sources for their theoretical calculations, but neither atmospheric temperatures nor specific humidity fields were measured, they were derived by running HADAM3 (four times).
They do not verify if HADAM3 is correct or not, they assume it. See: "Assuming that HADAM3 correctly captures etc., etc."
It means their result is neither measured nor verified. It is assumed.
Have a careful look at Fig. 3 (a) in Brindley 2001 please. This is the theoretical spectrum to be subtracted from the measured one to arrive at Fig. 1. Harries 2001.
You will notice H2O forcing is the decisive factor. Influence "SST only" (measured) is neutral, "T only" (not measured) overfills the CO2 notch in measured spectrum, while "H2 only" (not measured) is an exaggerated mirror image of it, if subtracted, re-creates the notch.
Therefore what you see in Fig. 1. Harries 2001 is the result of HADAM3 computations and has only extremely weak relation to IRIS or IMG data.
As we do not have actual specific humidity measurements along the entire air column over the East Pacific for the IRIS period and there is no way to go back in time and recover it, their result is utterly unverifiable.
When I was young, inherently unverifiable propositions used to belong to other realms of the human endeavor, not science.
Moderator Response: [DB] This goes no farther without links to proof of malfeasance. No more insinuations, no more implications. Further remarks not complying with the Comments Policy will be simply deleted. -
Stephen Baines at 03:26 AM on 29 April 2011How climate change deniers led me to set up Skeptical Science website
John Thanks again! A great resource. After looking through the debate KL was recently involved with (A Flanner in the works of Ice and Snow), I can't say I agree about his complaint. That thread is a good example of how patient members can be addressing concerns, and how moderating allows such a debate to stay focused on evidence... @ pbjamm #4 I read Foucault's pendulum and it made me a paranoid wreck for two weeks!!! The addictive nature of motivated pattern seeking is something that deserves more neurological and behavioral research. -
pbjamm at 03:21 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
dana1981, I am not sure this is an accurate representation of Lindzen's position. It seems to me from the quote that he is arguing that 1880 was an "anomalous minimum" so if it had been closer to the norm the difference between 1880 and 1981 would have been quite small, 0.1C. The Hadley data you link to indicates that he was incorrect about that but I think it a bit unfair to create the graph that shows him to be completely wrong about the average temperature in 1981, a value he surely knew.Response:[dana1981] I disagree. Lindzen disputed the accuracy of GISTEMP, and was wrong about 1880 being anomalously cold. The bottom line is that Lindzen claimed the planet only warmed 0.1°C between 1880 and 1989. That's precisely how I depicted his comments.
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Jeff T at 03:08 AM on 29 April 2011How climate change deniers led me to set up Skeptical Science website
John, Thanks to you and the many contributors who make Skeptical Science such a great resource. -
DSL at 03:06 AM on 29 April 2011How climate change deniers led me to set up Skeptical Science website
Ditto #4. Thanks, John, mods, et al. who patiently work through the problems and who, I might add, admit when they're wrong or haven't looked deep enough or just aren't sure. I wonder how much some understandings have changed over time through the mechanism of this site--especially among the regulars (from all sides). Certainly I have a much, much clearer understanding of the basic mechanics and complexity of the atmosphere. When I first started lurking around the global warming issue, I understood the greenhouse effect literally: CO2 was a cap. Ugh. -
dana1981 at 02:58 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
Tsumetai - sure, it's just a very rough adjustment to show that a model with 3°C sensitivity would have fit the data pretty well. -
Tsumetai at 02:50 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
So by scaling down from 4.2 to 3°C, I'm showing what the model output would have looked like had that been its sensitivity.
Well. Approximately, perhaps. Sensitivity tells you how high you'll end up, but it doesn't fix the shape of the path you take to get there. To scale down, you need to assume that global mean temperatures are at every stage a linear function of sensitivity, which probably isn't true in general. It may be sufficiently close to the truth to get in the ballpark. But Hansen's original projections are already in the ballpark. I'm not convinced there's any real benefit to going further than that. In this instance, it gives a nice result, but it's not clear that the agreement between your adjusted curve and the observed temperatures is actually meaningful. -
MattJ at 02:37 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
The article ends with the mildly provocative, "...one can only wonder what they must think about the massive underestimate of this warming based on Lindzen's 1989 comments." Well, I don't wonder, because I am very confident of the answer. The answer is that they and Lindzen are really hoping we just don't notice how massive the underestimate is. Unfortunately, they know that in the diffuse public debate, this massive underestimate will be challenged by far too few. -
Stephen Baines at 02:28 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
Yes, of course, I get it. Those are the IPCC predictions based on the model runs...you didn't calculate them based on the sensitivity on your own. Sorry...Need more coffee...Response:[dana1981]Well, they're Hansen et al.'s projections based on their model (this is pre-IPCC), but yes, you got the idea
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pbjamm at 02:25 AM on 29 April 2011How climate change deniers led me to set up Skeptical Science website
Reading through the comments section of the Guardian article is painful. The amount of anger and vitriol combined with the complete lack of anything resembling evidence makes me despair. It reminds me why I gravitated to this site a few years ago. Thank you John and everyone else who does the hard work here. SkS is a great resource for people who want to learn about Climate Science and AGW rather than denigrate it. If I want conspiracies I will re-read The Illuminatus Trilogy or Foucault's Pendulum. -
dana1981 at 02:23 AM on 29 April 2011Lindzen Illusion #2: Lindzen vs. Hansen - the Sleek Veneer of the 1980s
Stephen #2 - yes, 3°C is the equilibrium sensitivity, but remember, we're just showing the model output at any given time. So by scaling down from 4.2 to 3°C, I'm showing what the model output would have looked like had that been its sensitivity. The transient sensitivity is already incorporated into Hansen's model. -
Stephen Baines at 02:18 AM on 29 April 2011CO2 is plant food? If only it were so simple
Dawei, Very excellent to see all this info on a very hot topic. It cuts through a lot of the oversimplifications. There are a lot of scientists trying to get some sense of what the real net impact will be on plant productivity at the ecosystem scale, given all the higher order impacts on plant interactions, herbivory rates and nutrient cycles. It's a tough nut to crack, which is why no real consensus has yet emerged beyond the obvious physiological responses to CO2. I also would like to second Sphaerica's request to put the effects in context with effects of water availability as a controlling factor. Terrestrial ecosystem productivity varies almost 2 orders of magnitude among regions of the earth because of variation in precipitation. We're talking increases of 50% or less in real world production related to CO2.
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