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Comments 92351 to 92400:

92351. angusmac at 05:50 AM on 17 March 2011
       Climate Emergency: Time to Slam on the Brakes
       Albatross I will respond to @106 but it may take some time because I am trying to source data on your RC chart. However, I hazard a guess that the rest of SkS are total bored with our dialogue. Wake up SkS! It can’t be that boring – we all may learn somthing. If you are still following this please give us some encouragement. Meanwhile Albatross, I request that you desist from giving me personal advice – especially when it is patently wrong. For example @102, if I needed to replace my brake pads on my car, I would accept the advice of a service station technician as you suggest. However, if I needed someone to “break pads” on the car, I would go to a wrecker’s yard.
92352. Tom Curtis at 05:39 AM on 17 March 2011
       What would a CO2-free atmosphere look like?
       BP @61, assuming it was sensible to calculate a no feed back change to temperature from the removal of CO2, your method of doing so is so sloppy as to be worthless. Using Modtran, setting it to a US standard atmosphere and then adjusting the temperature down to approximately equal the effective temperature (-0.9 degrees), I then removed the CO2. The result was to increase OLR by 27 watts, increasing the effective temperature by approximately 10 degrees. The version of Modtran I used is obsolete, so this figure is not exact; but it is a far better estimate than your estimate by sloppy calculation based on generous (to your argument) estimates.
92353. shoyemore at 05:30 AM on 17 March 2011
       Maximum and minimum monthly records in global temperature databases
       Henry justice, Apologies, you will have to explain what you mean by "duration" in your post. Do you mean time between records?
92354. Henry justice at 05:06 AM on 17 March 2011
       Maximum and minimum monthly records in global temperature databases
       The number of maximum or minimum temperatures may or may not indicate warming or cooling. As such, the amount of warming or cooling is not quantified by such data. Without this quantification of warming/cooling, no conclusion should be drawn from just the number of the max or min only data without the duration added in in some form of units. In other words, you certainly can have three times the number of max warming vs cooling, but cooling can still be occurring due to their longer duration.
92355. Chris Colose at 05:02 AM on 17 March 2011
       What would a CO2-free atmosphere look like?
       BP, First off, a "CO2 frequency-band effective temperature" is highly wavelength dependent, moving from even colder than 240 K at the center to even warmer than 240 K toward the wings, and with spectral overlap with the other GHG's. You wouldn't even be able to define how the temperature would change using your methodology for a doubling of CO2, since the "bite" in the spectrum by more CO2 doesn't really get deeper at the center. Secondly, CO2 absorbs in a much more important place in the spectrum than in other conceivable spectral domains, say, toward the far tail of the Planck function. The "no-feedback" temperature change is approximately RF/(4*sigma*T^3), where RF is the radiative forcing and the denominator is the derivative of the Stefan-Boltzmann equation for a blackbody. For T=255 K, the denominator is about 0.26 K/(W/m2), which allows you to approximate the traditional ~1 C temperature change for a CO2 doubling. In contrast, by removing all the CO2, the RF is even more so a real value is closer to 7 C. As Albatross noted, your estimates don't include feedbacks at all, either surface albedo or the water vapor feedback.
92356. Rob Honeycutt at 04:38 AM on 17 March 2011
       What would a CO2-free atmosphere look like?
       BP... Don't you think it's just a little bit disingenuous to make a statement about Holocene variability compared to glacial periods by tossing up GISP2 data? You'd be more clear and accurate to say "Holocene variability above the Arctic circle..." The actual variability within the last glacial is not that much greater than the Holocene, and it's pretty well accepted (to my understanding) that Vostok is probably more indicative of global temperature than is GISP2.
92357. shoyemore at 04:29 AM on 17 March 2011
       Maximum and minimum monthly records in global temperature databases
       Eric (skeptic), #39, Yes ... but ... this method is used in a variety of situations in healthcare and industrial monitoring. It has a rich literature in reliability engineering and survival analysis. For example, a study on asthma in a collection of sufferers may only collect the datum "onset of attack", rather than patient peak flow measurement. Monitoring of computer systems may collect the datum "alarm recorded" rather than voltage or current, or the error count rather than the errors. Analysis of these "time to event" data is quite complex .. Rigdon & Basu Statistical Methods for the Reliability of Repairable Systems is a good introduction. It would be wrong to assume that a discrete count measurement has a lesser statistical significance than a measurement on a continuous scale. It is true that the references approach the counting of records from a different viewpoint, but I found no references with an approach like this one.
92358. RickG at 04:24 AM on 17 March 2011
       CO2 lags temperature
       trunkmonkey @ 297, I see a lot of hand waving but not a bit of supporting evidence to back up anything you said.
92359. Gilles at 04:13 AM on 17 March 2011
       Republicans to Repeal Laws of Physics
       Marcus : i'm speaking of the integral over time (ultimate recoverable ). I don't see how Germany or California could have proved anything concerning the integral production of the whole world throughout the century. I explain further if it's still unclear : a country owns an oil field containing 100 Gbl. With no conservation, it would be exhausted in 30 years. Now thanks to great effort in the world, consumption has been divided by two, so after 30 years , it still remains one half of the initial content. Will it stop the extraction just because "if nothing had been done, it would have been exhausted now?" Of course not -first because we wouldn't have any idea of what would have happened "if ..." , and second because it would be completely silly to stop the extraction when a lot of people still need it. We don't stop NOW the extraction of oil just because the oil growth curve has been strongly reduced after the first oil shocks ! (it has.). Concerning the alleged attitude of 'recommending" to spoil FF, I defy you to find a single post from me where I would have said that. " There's a whole WIKIPEDIA page here about the Creationism/Evolution 'controversy', and scientists like Spencer would claim that the debate is worth having and, therefore, isn't settled. Do you agree ? " Spencer is not a biologist. Newton believed in alchemy, I don't. Evrything is not comparable. As a general scientist, I find that many criticisms concerning an undue faith in numerical simulations and uncertain reconstructions are founded,and Mcintyre has already made relevant criticisms that have been acknowledged by the community, and published reviewed papers (which is not the case of astrologists for astrophysicists or creationnists, to my knowledge). But my main criticism is not about the uncertainty of models, which is acknowledged even by climate scientists : it's about the unreasonable amount of FF that are needed in most scenarios
92360. Berényi Péter at 03:53 AM on 17 March 2011
       What would a CO2-free atmosphere look like?
       #63 Albatross at 03:20 AM on 17 March, 2011 one can trigger a full snowball Earth with a sufficient reduction in atmospheric CO2 Perhaps one could. And a snowball Earth has much higher short wave albedo indeed. However, it has no bearing on our present situation. Area of ice covered surface is small relative to the entire surface in this interglacial, on top of that where there's ice there's no insolation for half a year. Therefore even if all the ice melted, the effect on global albedo would be negligible. Especially if low level clouds which tend to develop over ice free cold regions are taken into account as well. It just shows how fast climate sensitivity decreases with increasing temperatures. This is why Holocene temperature variability is an order of magnitude smaller than during glacial periods, don't you think?
92361. Rob Honeycutt at 03:52 AM on 17 March 2011
       What would a CO2-free atmosphere look like?
       BP... My point is that you're taking the same position as Lindzen and doing pretty much exactly what Lindzen did in front of the Congressional Subcommittee. Pulling a napkin out of your hat and saying, "Eh, I think would be about 2.5 degrees cooler" without hard research to back up the statement. Conversely, those who have done the hard research (Lacis, as mentioned above by Albatross) come up with completely different numbers. For me, napkin calculations just don't sway my opinion as much as published research. Now, if you could get that napkin worked up into a published paper then you (and Lindzen) might have something worthwhile to discuss.
92362. MattJ at 03:48 AM on 17 March 2011
       Maize harvest to shrink under Global Warming
       This is why I keep telling people in various online forums: bad as nuclear power is, even a thousand Fukushimas will not cause as many deaths in misery and agony as our continued use of fossil fuels, especially coal, causes due to rising famine, war and pestilence. I try to phrase it better than that, though;) Of course, it is still quite an uphill battle, because the same "green instincts" that usually accompany taking AGW seriously, also find nuclear power repellent. Then there is the widespread fear of radioactivity simply because it is invisible and poorly understood. TEPCO's incompetence both in handling the disaster itself and in handling the public relations around it don't help, either.
92363. Chris G at 03:33 AM on 17 March 2011
       Republicans to Repeal Laws of Physics
       Gilles, Regarding, "Lindzen , Pielke, Curry ... They may be wrong, but I'm not qualified to say that" So, it is an appeal to authority argument. Let's examine your authorities: Lindzen - Agrees that CO2 is a greenhouse gas and that more of it will change the thermodynamic properties of the earth, but believes through a bit of complicated math that the earth's climate will regulate itself and thereby prevent changes dangerous to us. This is despite a geologic record which does not give one the sense that the climate is inherently stable. He reminds me of the guy who "proved" that heavier-than-air flight was not possible; it is not clear what he thought of birds. Well, actually, there was more than one who believed this, but Lord Kelvin was one of them. My point is that Lindzen may be highly competent, but the evidence is against him. Peilke - I have no comment. Christy - He seems to be saying that either the observed warming is not really observed, and/or that we don't know anything because we don't know everything. Curry - I sometimes have trouble reconciling the different statements she makes, but that could just be me. In any event, she also has stated that the warming is real and that it is potentially dangerous. Her range of possibilities include some scenarios under BAU that are pretty much game-over situations. So, I don't believe that she is a good authority for supporting BAU. You are using an appeal to authority, and the vast majority of the authorities are against you. The only efficient way to stabilize the CO2 content of the atmosphere is to quit putting more into it. As I understand it, the current bill does not counter the findings of the EPA that higher levels of CO2 are dangerous, it just removes their ability to regulate CO2. The vast majority of authorities agree that things will get catastrophically bad if BAU continues until we run out of fossil fuels. Like Yul Brynner, at some point, we will quit using fossil fuels. The sooner we do that, the less chance we have of developing a fatal condition. The current bill would delay when we quit.
92364. trunkmonkey at 03:25 AM on 17 March 2011
       CO2 lags temperature
       294. "the problem (as with a lot of problems in paleoclimate) is not finding a solution but that there are more solutions than the data can constrain." Sad but true. The only data that can really constrain anything come from the last sixty years and everything pre satellite is sketchy. Paleoclimate is really a logic excercise where you are lucky when the disparate signals from proxies give you a correlation. What is unique about the Antarctic ice core data (although the "down under" data point is less than ideal) is that they give us independent signals for both temperature and CO2 at the same time and in the same medium. I believe that the clear signal that temperature lead CO2 in these data is an extremely important clue that is not adequately explained by Milankovitch. Invoking Occam, we should probably suppose that temperature has lead CO2 for all of earth history, or at the very least in prior glacial episodes.
92365. Berényi Péter at 03:23 AM on 17 March 2011
       What would a CO2-free atmosphere look like?
       #62 Rob Honeycutt at 03:08 AM on 17 March, 2011 I don't think even Lindzen has any research that backs that up I am not talking about Lindzen's research, but actual data and simple back of the envelope calculations. It does not show changes in surface temperature directly, it's about the temperature of terrestrial photosphere. However, if environmental lapse rate does not change dramatically, it should translate to a surface temperature anomaly of the same order of magnitude.
92366. Albatross at 03:20 AM on 17 March 2011
       What would a CO2-free atmosphere look like?
       BP @61, "Of course it is a very crude approximation. The actual value can be anywhere between 2°C and 3°C." Quick, submit a rebuttal to Lacis et al. in Science, all based on a short bog post and a "very crude approximation"-- post normal blog science lives, and what is more we do not have to worry about the consequences of doubling CO2 b/c its effects on global SATs are minimal! Hang on though, first you might want to read their paper....I see no consideration for feedbacks in your "analysis" BP, other than the plants dying because they have no "food". From the main post, b/c you seem to have not read it: "There have been a number of studies which examine the evolution of the climate system with no CO2 in the atmosphere. Such experiments are described for example in Pierrehumbert et al (2007) , or by Voigt and Marotzke (2009). From these papers, one can trigger a full snowball Earth with a sufficient reduction in atmospheric CO2. A substantial reduction in water vapor (shown below, from Lacis et al (2010) as well as increase in the surface albedo are important feedbacks here, showing that removing the non-condensing greenhouse gases (mostly CO2) in the atmosphere can collapse nearly the entire terrestrial greenhouse effect. What’s more, since the albedo increases substantially, the total greenhouse effect can be thought of as providing even more than 33 K of warming relative to Earth’s blackbody emission temperature."
92367. pbjamm at 03:15 AM on 17 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       It would be very helpful if PhysSci would actually state his position and present his argument. If you are unwilling to do so until after you publish your paper then please wait til then to comment on it.
92368. Rob Honeycutt at 03:08 AM on 17 March 2011
       What would a CO2-free atmosphere look like?
       BP... I don't think even Lindzen has any research that backs that up. It's little more than a bit of wishful thinking pulled from a tattered top hat that would justify his sloppy research.
92369. Albatross at 03:06 AM on 17 March 2011
       Republicans to Repeal Laws of Physics
       Gilles, I have not read all of your rant above @157, I almost stopped when I read this fallacy posted by you: "Even McIntyre is a real statistician who knows his stuff." McIntyre is not a real statistician, and has been shown to not know his stuff. He is a conduit for misinformation and a lap dog for the Republicans, "skeptics", contrarians and those who deny AGW. He also has a personal vendetta against Dr. Mann. Finally, a source (referring to you quoting the IPCC), something substantive. The SRES scenarios are the best that we have, and thus far the projections have been on the conservative side, that is not encouraging, and not consistent with your opinion voiced here. Who to place more weight on, a contrarian on the web or the imperfect SRES? Easy, SRES and the work that has since been done since which Daniel Bailey linked us to above. "I think it's difficult only if you don't really listen to what I'm saying, but judge me with your prejudices." Nonsense, you have for all here exposed your bias, prejudices, so please do not project those onto me. In fact, it is you who is judging the IPCC and climate scientists with your prejudices and are failing to listen to the informed people both here and at RC. I am judging you on your inability to make a consistent, coherent and fact/science-based argument, and your inability to get your facts straight. No efficiency alone is not going to reduce GHG levels or net emissions, it is part of the wedge approach proposed by Pacala and Socolow. More science for the Republicans to ignore. Giles, I am not going to continue debating with you, and providing you a platform to perpetuate your misinformation.
92370. Berényi Péter at 02:57 AM on 17 March 2011
       What would a CO2-free atmosphere look like?
       "An answer was provided by MIT scientist Dr. Richard Lindzen, who suggested that such a hypothetical removal of all the CO2 in the air would translate into a global cooling of about 2.5 degrees, presumably in Celsius" Yeah, that's about right. As you know effective temperature of a body is the temperature of a black body that would emit the same total amount of thermal radiation. Effective temperature of Earth as seen from outer space is about 255 K. This value does not depend on CO₂, neither on any other GHG for that matter. It is entirely determined by the solar constant and the short wave albedo of the planet. We can also define effective temperature of Earth for a restricted frequency range like the main CO₂ band between 18 and 22.5 THz (which includes the wings) the same way. Currently it is about 240 K. As for realistic temperatures (let's say between 220 & 290 K) a black body emits about 16% of its radiation in this frequency band, it means effective temperature of Earth outside the main CO₂ absorption band should be some 257.5 K to still produce a 240 W/m² overall OLR. Now, if we removed the carbon dioxide from the atmosphere, effective temperature inside and outside this band would both be 255 K, which is a decrease of 2.5°C. Of course it is a very crude approximation. The actual value can be anywhere between 2°C and 3°C. Not to mention the fact if we removed all the carbon dioxide, we'd kill plant life, which would change short wave albedo by eliminating evapotranspiration entirely. Fortunately there'd be no one to notice it, because with no food people are inclined to starve to death.
92371. Chris G at 02:51 AM on 17 March 2011
       Republicans to Repeal Laws of Physics
       I thought this Dilbert would be appropriate, and perhaps provide some levity.
92372. Rob Honeycutt at 02:32 AM on 17 March 2011
       Skeptical Science nominated for Climate Change Communicator of the Year
       Albatross... If I might add an analogy: Science, that is "real" science as done within scientific circles by professionals whose field of expertise is in the subjects they are researching, is like a wrestling match; like Greco-Roman wrestling. True tests of strength and agility. It uses clear rules that both sides abide by that assure fair play and legitimate measure of the best athlete. "Skeptic" (note the quotes) climate science as played out on blogs (i.e., WUWT) is the WWF. Sure, there is athleticism in the WWF (or WUWT). I would never begrudge that. But it's not a real test of athleticism (science). And similarly, WWF plays very well with the general public where Greco-Roman wrestling can hardly hold peoples attention unless they are directly involved somehow.
92373. SNRatio at 02:22 AM on 17 March 2011
       Maize harvest to shrink under Global Warming
       While studies like this give strong indications, I would be very careful when it comes to actual estimation. Implying that we may have too little knowledge as of yet about how large the net effects will be. There are too many parameters which I think are not properly controlled here. Adaptations in genetics, growing techniques etc may to some extent mitigate. I would also be careful about generalizations. While there may be very good support for a claim that warming, all other factors held constant, will reduce crops, all other factors will not be held constant in practice. But extrapolating from past improvements is even worse, I think..
92374. michael sweet at 02:03 AM on 17 March 2011
       And so castles made of sand fall in the sea, eventually
       Idunno, I have seen several posters recently suggest sea level rise would stabilize the gas clathrates. The addition of 2 or 3 meters of water would only add a small amount of pressure. The temperature change is much more important in their stability. We are currently changing the temperature in a big way. I am 52 years old. Even a house in the Florida Keys (very low land near Miami) would be unlikely to be inundated in my lifetime. Decision makers like Dick Cheney, who is older and in poor health, do not care if Miami is inundated in 40 or 50 years. My students were excited about Inconvienent Truth and sea level rise when it first came out. When they realized that the projected 20 foot sea level rise would not occur for 100-250 years many said "my grandchildren can deal with it".
92375. chudiburg at 01:48 AM on 17 March 2011
       It's cooling
       Thanks guys. I must have missed that we are in the midst of a la nina year. That explains some of the temporary cooling (compared to the last few years at least) I also liked the analogy about how much you grow in a day vs. a week/month/year. Keep up the good fight gentlemen. Cheers!
       Moderator Response: [DB] Cheers to you, too. BTW, Feb data is now available from the GISS link I provided earlier.
92376. les at 00:45 AM on 17 March 2011
       Republicans to Repeal Laws of Physics
       

       Following on from 159 JMurphy/Gilles.... The "there is debate so the science isn't settled" argument is a real tell that someone really knows little about how science actually works. To illustrate. There was a fascinating paper in Nature the other week on olification. Really it's not clear - it turns out - which proteins process which molecules do smell, or how - shape or vibrational state. Vibration theory of olfaction .v. Shape theory of olfaction Yet no one goes round saying "smell isn't real" or "I'm not prepared to smell anything till the science is settled". The American legislature doesn't vote against perfume sales etc. etc. There is legislation that keeps down bad smells in various places. I've no doubt there are people who lobby for and against such things. The facts are that we can smell things. It's an objective, measurable (to some degree) fact. That we don't know how it works beyond any doubt is neither here nor there... The settledness of the science is immaterial. OK, compared to the climate; it's of less economic importance, impacts on peoples lives less... but that's not the point if you're arguing that "... so long as scientists debate... things are not settled". No. That is the attitude of someone who has never been closer to science than "The Cookie Monster Drop an Apple and Explains Newton" episode of Sesame Street. Real science is knee deep in uncertainties, debates and alternatives... which embed within a settled science.

       Moderator Response:

       [DB] Another good example is the internal combustion engine. The fact that few people have any real idea how they work doesn't stop them from driving a car.

92377. KR at 00:35 AM on 17 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       Tom Curtis - Excellent and very clear explanation here at @563; thanks!
92378. RickG at 00:34 AM on 17 March 2011
       Skeptical Science nominated for Climate Change Communicator of the Year
       Ken Lambert: Censors just keep deleting my replies - so I guess the message is that this site has put up the shutters and is only wanting to hear from the true believers. Considering recent posts by "PhysSci" I would suggest your claim has no support. Maybe your deletions have something to do with the comment policy.
92379. Arkadiusz Semczyszak at 00:33 AM on 17 March 2011
       The name is Bond...Gerard Bond.
       @Tom Curtis I agree ... Information from Wikipedia might already be outdated. Changes may be slow. See here. Sorry is my "oversight" - should verify the information in Wikipedia. P.S. About my link - it’s refers to a global phenomenon that affects the Sahara.
92380. KR at 00:30 AM on 17 March 2011
       2nd law of thermodynamics contradicts greenhouse theory
       PhysSci "Gentlemen, absorption and re-emission can only redistribute available energy, but cannot produce extra heat in the atmosphere needed to explain the near-surface thermal enhancement presently called atmospheric 'greenhouse effect'." PhysSci, that would be true if the climate were a static, fixed energy system. However, the climate is an open ended energy flow, not a static distribution. Energy will accumulate or dissipate based upon flow rates until input energy equals output energy. Given the limiting throughput of the atmosphere, there is more accumulated energy at the surface than the instantaneous flow rate, but that instantaneous flow rate of 240 W/m^2 enters the system and leaves it. Sorry, Tom Curtis, another analogy. PhysSci, water flows down a river, into a dam, and out the other side. The water is much deeper at the dam than in the upstream river, pressure at the bottom of the dammed lake is much higher than at the bottom of the river, but the flow rate in and out of the dam is equal, or the level at the dam will change until that is true. Your complaint is inappropriate for this situation. Sadly, PhysSci, it is becoming apparent to me that your grasp of the physics involved is not terribly strong. I suggest more reading on your part.
92381. witsendnj at 00:29 AM on 17 March 2011
       Maize harvest to shrink under Global Warming
       Maybe the results wouldn't be quite so surprising had the researchers factored two undisputed and well-established (although generally ignored) tenets into their calculations: 1. more heat = higher levels of tropospheric ozone and; 2. tropospheric ozone is toxic to vegetation - multiple international studies have conclusively demonstrated that at ambient levels ozone is already significantly (5 - 80%) reducing both crop yield and quality and that amount is expected to increase as climate change continues. http://witsendnj.blogspot.com/p/basic-premise.html
92382. Ken Lambert at 00:21 AM on 17 March 2011
       Skeptical Science nominated for Climate Change Communicator of the Year
       Rob and Albatross Censors just keep deleting my replies ( -Snip- )
       Moderator Response: [DB] Your first response was deleted because it was a long comment filled with a multitude of topics found on many other threads. This forced a moderator response, as it amounted to a Gish Gallop. Subsequent complaints about moderation do not help, as you should well know. Comments that are succinct to the topic of the thread they are posted on which also comply with the Comments Policy receive no moderation. You are welcome to resubmit your individual points on the appropriate threads, with a summary response posted here pointing to each individual thread. This is how business is done here to keep the dialogue on individual threads on topic. And again, this is something you have been repeatedly counseled on.
92383. JMurphy at 00:03 AM on 17 March 2011
       Republicans to Repeal Laws of Physics
       Gilles wrote : "My position is that as long as scientists debate, there is a debate. Lindzen , Pielke, Curry are NOT politicians or astrologists. Even McIntyre is a real statistician who knows his stuff. They may be wrong, but I'm not qualified to say that. I'm just observing that things are not settled." There's a whole WIKIPEDIA page here about the Creationism/Evolution 'controversy', and scientists like Spencer would claim that the debate is worth having and, therefore, isn't settled. Do you agree ? As for McIntyre, could you tell what you mean by him being a "real statistician" ? What do you base that on, considering that you don't feel qualified to judge ? Is it just fact that he (and a few others) are arguing from a minority position, therefore they must have a valid point somehow ? How have you determined that ?
92384. Lou Grinzo at 23:49 PM on 16 March 2011
       Maize harvest to shrink under Global Warming
       johnd: I would say this study does tell us something we didn't know -- it quantifies the effects you mentioned. It's one thing to say "condition X is sub-optimal compared to condition Y" and quite another to know just what the impact is in change from Y to X. Surely various studies will arrive at different values -- look at the assessments of the life cycle carbon savings from ethanol, which are all over the map -- but given the implications for humanity and public policy, I would rather see us start soon with a possibly flawed set of studies and work (quickly) to improve them than to guess.
92385. johnd at 23:29 PM on 16 March 2011
       Maize harvest to shrink under Global Warming
       Does this tell us anything that is not already known? Commercial croppers know the optimum growing conditions required for the crops they grow, and based on how seasonal conditions are progressing, and forecast, will adjust their sowing time accordingly. Grow out of season and the results will disappoint. Nor is the season ruled by the calender. This is why accurate forecasts are so important to croppers, and why many are prepared to pay private forecasters handsomely for a premium product. It is really no surprise that if the conditions change after sowing, or if the crop is sown late, that the yield will be effected. As for how the trials were conducted, I can't understand why they had to use data from local weather stations remote from the trial sites if these were properly controlled trials on research stations. The weather data should have been collected at the trial plots by those conducting the trial, especially if irrigation was being used, as it was. It has happened here in Australia where trial results have been invalidated because the rainfall data was collected from nearby stations, not from the actual trial location. I also don't understand this rationale behind this artificial adjustment if the trials were producing yields that could be physically measured- "The net effect of warming on yields was computed for each trial by artificially raising observed temperatures on each day by 1 °C, recomputing temperature indices such as GDD8,30, and using the regression equations to predict the new yield." Can someone explain the reason for having to do this?
92386. Arkadiusz Semczyszak at 23:23 PM on 16 March 2011
       Maize harvest to shrink under Global Warming
       “... a new study demonstrating once again, that global warming will generally have a very negative impact on food production.” That conclusion is nothing “illegitimate” - optionally may apply only to maize and part of Africa. “Projected impacts relative to current production levels range from −100% to +168% in econometric, from −84% to +62% in process-based, and from −57% to +30% in statistical assessments.” (Climate change risks for African agriculture, Müller et al., 2011.) “Despite large uncertainty, there are several robust conclusions from published literature for policy makers and research agendas: agriculture everywhere in Africa runs some risk to be negatively affected by climate change; existing cropping systems and infrastructure will have to change to meet future demand.” Only this request has a strong scientific basis - but only for Africa. Interannual variability and climate sensitivity of Net Primary Productivity: a process-based multilayer-canopy vegetation model compared against observed tree-ring width, Bodin, Alton, and Krakauer, 2010.: “We estimate a global increase in NPP of 0.32% yr - 1 over the period 1951-2000. This is in approximate agreement with previous studies. Most of this increase can be attributed to CO2 fertilization rather than climate change.” Generally ... - this is the 0.32% NPP increase per year in the Positive.
92387. CBDunkerson at 22:54 PM on 16 March 2011
       And so castles made of sand fall in the sea, eventually
       Daniel Bailey in #5: "Seize every chance possible over the next few years to unload low-lying real estate near the sea." I've often found myself wishing I could think of a way to 'invest' in the continuation of global warming... and encourage 'skeptics' to invest in its supposed non-existence. With those who deny the possibility of fossil fuel depletion you can invest in the alternative energy sources which must eventually replace them... though picking which alternatives will do so is still a gamble. For GW I suppose one could buy real estate along the 'future coastline', but again that would be a gamble in determining exactly where that will end up. Anyway, the underlying point is that I think we've arrived at a world where denial of reality is status quo for large sections of the population. One way of changing that would be if clinging to such irrational beliefs hurt them financially in a directly visible way. Currently the 'scam artists' get away with it because they can always divert blame elsewhere or change their stories as the situation changes. Make falling for these scams a direct hit on the pocketbook and they could no longer continue ad infinitum as they do now.
92388. Lou Grinzo at 22:50 PM on 16 March 2011
       Maize harvest to shrink under Global Warming
       I'm glad to see SkS highlighting this information, because I think it's one of those "little details" that has immense implications. If you start with large, sustained (for now) CO2 emissions, you see a range of effects, some of which interact with each other, and most wind up in some way affecting humanity's ability to feed itself. Given the role that drought, rising sea levels (and the resulting salt water incursion into coastal farm land and wells), and population growth will have our situation, even a small decrease in our ability to grow a major food is a very big deal.
92389. Tom Curtis at 22:29 PM on 16 March 2011
       The name is Bond...Gerard Bond.
       AS @20, if you want to trump the variety of papers I linked in suport of the slow drying of the Sahara, perhaps you coud find something more recent than a seminar in 1998 (the source of the Wikipedia claim). For your edication: The onsite evidence clearly shows a gradual drying. Your scientific link, by the way, does not discuss the drying of the Sahara.
92390. bananabender at 22:21 PM on 16 March 2011
       Greenhouse effect has been falsified
       John Tyndall actually measured heating in carbonic acid solutions of various concentrations (CO2 dissolved in water) illuminated by gas flames. He didn't measure the absorbance of IR in purified gases. Knut Angstrom, an expert is solar radiation, proved that Arrhenius' calculations were wildly incorrect and based on an improper methodology. The fact that the Earth is warmer than the Moon simply proves that the oceans and atmosphere of Earth have an "atmospheric warming effect". It certainly doesn't prove the existence of a "Greenhouse Effect" due to CO2 or any other gas. All the planets(except Mercury which has no atmosphere) have an atmospheric warming effect that correlates directly with the pressure of the atmosphere. This is regardless of the actual atmospheric composition. The most important source of warming on Earth is the transfer of latent heat via evaporation and condensation. This is why coastal areas have far less variation between day and night temperatures compared with deserts. This is despite the concentrations of "GHGs" being the same. The satellite data simply shows that the Earth is radiating more heat. This can be caused by the upwelling of warm ocean water. It does not prove the existence of any Greenhouse Effect.
       Moderator Response:

       [Daniel Bailey] Angstrom's error was in treating the atmosphere as a single layer. Later studies (of which they are legion) conclusively show that portion of his work to be in error. The GHG effects of CO₂ are considered established fact. For a more in-depth discussion, see here, here and here.

       The remainder of your comment is in error. So I recommend that you also read Newcomers, Start Here and then learn The Big Picture. I also recommend watching this video on why CO₂ is the biggest climate control knob in Earth's history.

92391. idunno at 22:20 PM on 16 March 2011
       And so castles made of sand fall in the sea, eventually
       Hi all, This is something of a repost. Sorry if the previous one contravened the guidelines. Looking at the graphs on Hansen 2011, linked by Daniel@4, page 6, it seems that there is a clear relationship between temperature, levels of greenhouse gases and sea level in the geological record. The fact that sea level rises with ocean temperature may well have been an important mechanism of the self-regulation of the biosphere's temperature. A rise in sea level applies a greater amount of pressure on the submerged deposits of methane clathrates and other methane hydrates dissolved within the water column. If the current warming proceeds too rapidly, the temperature may increase far more quickly than the corresponding increase in pressure, which will perhaps lead to a dangerous erosion of the clathrate stability zone. So, and I do not claim this is an expert view, merely a subject for discussion, it may just be that the rise in sea levels is currently dangerously slow. Dangerous because it could lead to a potentially catastrophic release of methane - CH4.
92392. Marcus at 22:13 PM on 16 March 2011
       Republicans to Repeal Laws of Physics
       So what you're saying Gilles is that, because we can't 100% guarantee that improving efficiency will reduce total emissions (even though nations like Germany & States like California have proven that it does) that we shouldn't even try? Wow, talk about a defeatist attitude-the fossil fuel industry loves people like you. You're the kind of person that Stalin once described as a "useful idiot". I'll give you this iron-clad guarantee: improving efficiency & reducing the amount of energy we derive from fossil fuels will-at the very least-slow down the rate at which GHG emissions rise over the next century compared to the BAU approach that you seem to keep recommending. Of course, if we take a more realistic approach to population growth & restore some of our lost carbon sinks, we might actually get GHG emissions to levels lower than the current century. "I think it's difficult only if you don't really listen to what I'm saying, but judge me with your prejudices." No its not prejudice, Gilles-you claim not to be pro-fossil fuels, yet every comment you've made has been to effectively spruik the ongoing, inefficient use of fossil fuels for many decades to come.
92393. Arkadiusz Semczyszak at 22:08 PM on 16 March 2011
       The name is Bond...Gerard Bond.
       #Tom Curtis Sahara “... and dissipated slowly in the period 5000 to 3000 before the present.” That's not true. wikipedia: “A curious discovery from the marine sediments is that the transitions into and out of this wet period occurred within decades, not millennia as previously thought.” A major widespread climatic change around 5300 cal. yr BP at the time of the Alpine Iceman Magny & Haas, 2004.: “It has possible equivalents in many records from various regions in both hemispheres dating to 5600–5000 cal. yr BP and corresponds to global cooling and contrasting patterns of hydrological changes.” Sahara is the result of synchronous global cooling for the SH and NH.
92394. Rob Painting at 22:06 PM on 16 March 2011
       CO2 lags temperature
       Rick G -

       if you are going back pre-Quaternary you need to account for paleo-geography

       And orography (mountain-building), and the rise of angiosperms (flowering plants). The climate models show some pretty marked cooling when these are accounted for.
92395. Arkadiusz Semczyszak at 22:05 PM on 16 March 2011
       The name is Bond...Gerard Bond.
       I was late to this interesting discussion. But II have to give a few remarks ... Wikipedia says: “Bond et al. (1997) argue for a climate cyclicity close to 1470 ± 500 years in the North Atlantic region.” I feel the most convincing explanation of the paper (with references the paper cited by Cambrun): Holocene climate variability in northernmost Europe, Allen et al., 2007.: “Time-series analysis of pollen analytical and sediment geochemical data indicates that each exhibits statistically significant periodic behaviour (at periods of ca 190, 410, 1050, 1650 and 1810 yr). The periods detected suggest this behaviour may reflect regional expression of climate system responses to solar variability and/or of effects upon tides and ocean circulation of periodic lunar orbital variation.” The Sun This figure (panel solar cycles) explains part of differences in the length and intensity of events Bond. I I also recommend this work: Linking solar forcing with climate and primary productivity changes in the Northeast Pacific: evidence from mid to late Holocene laminated sediments, Patterson et al., 2011. The Moon Impacts of late Holocene rapid climate changes as recorded in a macrotidal coastal setting (Mont-Saint-Michel Bay, France), Billeaud, Tessier and Lesueur, 2009.: “The sedimentary expressions of rapid climate changes vary according to the different subenvironments within Mont-Saint-Michel Bay; cycles, a few meters thick, can be correlated throughout the bay, and radiocarbon dating suggests that they have a millennial time scale. The various changes reflect an increase in wave dynamics in association with Bond cold events, possibly in conjunction with long-term (1800 year periodicity) tidal cycles.” It is worth noting that the solar cycle Hallstad - c. 2300 years - is about c. 500 years longer than the tidal cycles. The events of Bond - in the past - there asynchrony between NH and SH but in two points, however, we notice the coincidence. Both the end of the last glaciation and the optimum - the middle Holocene occur synchronously on the NH and SH (like the current warming). Here we see a periodicity of about six thousand. years. Most likely, the recently discovered solar cycle 6 thousand. years is so strong that it (through the effects of second-order?) - can be a superposition of cycles - equally affecting - globally at the same time - climate change in the SH and NH. The optimum climate synchronicity middle and late Holocene in both hemispheres-evidenced by numerous works on southern hemisphere (also shows warmth at the same time - NH): Antarctic ice cores, cave stalagmites, glaciers, alkenones in seabed cores off Chile, etc.. The latest paper I recommend: Ice core: Antarctic lakes suggest millennial reorganizations of Southern Hemisphere atmospheric and oceanic circulation, Hall et al. 2010.: “Here, we present new data from closed-basin lakes in the Dry Valleys region of East Antarctica that show high-magnitude, high-frequency oscillations in surface level during the late Pleistocene synchronous with climate fluctuations elsewhere in the Southern Hemisphere. These data suggest a coherent Southern Hemisphere pattern of climate change on millennial time scales, at least in the Pacific sector, and indicate that any hypothesis concerning the origin of these events must account for synchronous changes in both high and temperate latitudes.” Marine sediment core: Holocene Southern Ocean surface temperature variability west of the Antarctic Peninsula, Shevenell et al., 2011.: “On millennial timescales, abrupt SST fluctuations of 2–4 °C coincide with globally recognized climate variability8. Similarities between our SSTs, Southern Hemisphere westerly wind reconstructions9 and El Niño/Southern Oscillation variability10 indicate that present climate teleconnections between the tropical Pacific Ocean and the western Antarctic Peninsula11 strengthened late in the Holocene epoch.”
92396. Gilles at 21:56 PM on 16 March 2011
       Republicans to Repeal Laws of Physics
       "Gilles @142, Nice try to reframe the argument, but I can only assume that those practices to which you refer (cherry-picking etc.) are those which have been engaged in by "skeptics" and contrarians, including those who have testified to Congress on behalf of the Republicans. So yes, I hope that you will join us in condemning the misinformation and distortion presented by the likes of Lindzen, Christy, Michaels, Pielke Snr and Monckton (their misinformation has been well documented here at SkS and elsewhere) to the US Congress and people of the USA. And that is before we have dealt with the so-called "post-normal science" crowd, whose scientific misconduct has been well documented and is the subject of at least one investigation." My position is that as long as scientists debate, there is a debate. Lindzen , Pielke, Curry are NOT politicians or astrologists. Even McIntyre is a real statistician who knows his stuff. They may be wrong, but I'm not qualified to say that. I'm just observing that things are not settled. " "SRES scenario have no predictive power, they are not based on known and validated laws, they have no associated probability - it is just some set of possible histories, which may all be quite unlikely." Wow, if you wish to have any credibility, at least try and back up your beliefs with some substance, citations, and science. This kind of vacuous arm waving serves no purpose. And yet you somehow feel free to accuse others of not quantifying the probability?.... " well , I suppose that IPCC is a valuable source ? http://www.ipcc.ch/ipccreports/sres/emission/index.php?idp=25 "Scenarios are images of the future, or alternative futures. They are neither predictions nor forecasts. Rather, each scenario is one alternative image of how the future might unfold. A set of scenarios assists in the understanding of possible future developments of complex systems. Some systems, those that are well understood and for which complete information is available, can be modeled with some certainty, as is frequently the case in the physical sciences, and their future states predicted. However, many physical and social systems are poorly understood, and information on the relevant variables is so incomplete that they can be appreciated only through intuition and are best communicated by images and stories. Prediction is not possible in such cases " blah, blah , blah .... " How do you reconcile this statement made by you: "Most SRES scenarios were already wrong when they were published, because the fuel consumption in the 90's was already greater than their prediction"" With your claim that "560 may be reachable in the far future - I don't think that it will be a catastrophe either." " just because there is no obvious link between a current growth rate and an ultimate integral value. " Well, it is difficult to keep track of your position on this amongst all the arm waving. OK, so we agree that the EPA should be permitted to regulate GHG emissions which will reduce FF consumption and pollution." I think it's difficult only if you don't really listen to what I'm saying, but judge me with your prejudices. Again : Improving the EFFICIENCY doesn't insure that we will reduce the total emission rate, and even limiting the RATE of GHG emission doesn't insure at all that we'll limit the INTEGRATED AMOUNT of GHG. Do you agree at least with this assertion ?
92397. Eric (skeptic) at 21:56 PM on 16 March 2011
       Maximum and minimum monthly records in global temperature databases
       I don't think the three references are applicable (although they are a related topic). The first paper had a dead link, but I found a paper by Benestad in 2004 http://regclim.met.no/results/Benestad_GPC2004.pdf that may be similar. The datasets in the papers have a lot more points to derive a statistical trend. When you used only one GAT series (one reading per month) instead of many readings per month used in the papers, your result has less statistical signifigance and reflects some global biases such as ENSO popping records at a higher rate in the 90's. OTOH, the benefit of using GAT is that UHIE has been accounted for.
92398. RickG at 21:41 PM on 16 March 2011
       CO2 lags temperature
       scaddenp: ...the orbital variations have probably been constant as long as there has been life on earth, yet glacial periods are exceptional in earth history.We're just lucky I guess? If you are going back pre-Quaternary you need to account for paleo-geography, i.e., continental drift. If you don't have a continental mass at the poles or at least enclosed around a pole as is present day, it is not likely an open ocean is going to freeze. Further consideration would be different ocean circulation and a dimmer sun.
92399. Rob Painting at 21:24 PM on 16 March 2011
       Maize harvest to shrink under Global Warming
       Adelady - Thanks for pointing that out. Some glitch that inserts extra characters into the link, so I can't fix it. I've deleted the link, and MichaelM has kindly provided the map I was attempting to highlight. cloa513 - Not sure what your point is. Bern - Clearly the picture will be different with changing rainfall patterns, however allowing only for temperature, yield declines and this is amplified by drought. Heat seems to affect the reproductive (flowering) process. The authors also point out the trials used artificial (nitrogen) fertilizers, whereas most African farmers don't. Under nitrogen stress (the typical African farm) the response to heat & drought is reduced. The end result being the trials slightly exaggerate the stress response.
92400. MichaelM at 20:44 PM on 16 March 2011
       Maize harvest to shrink under Global Warming
       Until the 'dotted link' is fixed here it is.

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