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Comments 51 to 89 out of 89:

51. Tristan at 01:26 AM on 22 April, 2012
    Not sure if I'll be able to stand watching either.I may be underestimating the two young ladies on our side, but I'd have felt more comfortable knowing that someone of JC's calibre were defending the scientific position.
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52. caerbannog at 01:27 AM on 22 April, 2012
    Wow -- the WUWT discussion thread that I linked to above has turned into a completely stunning train-wreck. I mean, how many ways does one have to explain that 15GT/year is less than 30GT/year before some people will acknowledge that natural processes are acting as a net CO2 *sink*? So let me add my own item to the "How we know we are right" list. 11) We are willing to accept the result of a simple subtraction operation, even if that result is less than 0.
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53. climatehawk1 at 01:31 AM on 22 April, 2012
    Well, in the spirit of "Everything has been said, but not everyone has said it," let me add my two cents. "I don't believe anything" or "I wish to not believe anything"--bold statements, but I think they belong in the Platonic realm. Even if you only look at data you have derived yourself, you're still believing the data exist and are telling you something about the subject of study. Like Bill and JimF above (JimF, I'm guessing here, so please excuse me if I'm wrong), I'm not a scientist. I'm a specialist in communications. I believe in basic physics and in the science I see revealed regularly in peer-reviewed publications, and I don't think it's mistaken or unwise to do so--we cannot all perform our own experiments. I "believe" that if I jump out a 10th-story window, I'm going to die, even though I've never done it personally and therefore don't "know" it. I agree that we're losing, but that won't last, because we have the ultimate rebuttal--the weather, and especially what the weather is going to do to food crops and economies. So the scientists have to keep doing the best science they can, and we communicators have to keep doing the most effective communicating we know how to do, and try to shorten, as much as we can, the time between now and when effective action is taken to mitigate climate change and lower atmospheric GHG concentrations. Oh, and how do we know we're right? We don't, but as someone pointed out here recently in exhaustive detail, there are virtually no peer-reviewed publications on climate science from the camp of those in denial. I take that as working evidence unless and until such evidence appears.
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54. Dikran Marsupial at 01:41 AM on 22 April, 2012
    caerbannog I know I said "I don't think that we are sure that we are right", however that the rise in atmospheric CO2 is anthropogenic is probably the fact that is known with least uncertainty; we can be pretty confident we are right on that particular issue! As such it is ironic that some skeptics still can't accept it, even when someone like Fred Singer says on record that such canards only serve to give the skeptics a bad name!
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55. funglestrumpet at 02:33 AM on 22 April, 2012
    Yet again the discussion centres on whether we as a species are responsible for global warming or not. Just imagine for one moment that our certainties about AGW are in fact misplaced and Mr Watts, Professor Salby and that small number of like minded individuals who are of a similar opinion, are actually right about global warming and we are not the cause. It might be that the current warming is actually due to some as yet undiscovered aspect of the natural carbon cycle that has the effect of increasing atmospheric CO2 concentrations. Or, it might be that the IPCC, despite all its credentials, is wrong on the issue and the warming is due to the Sun. Alternatively, it might be due to a global increase in flatulence resulting from eating genetically modified crops. Would that mean that we should not do whatever we can to limit the warming that we are experiencing (especially if it is due to the latter)? I sincerely hope not. I rather think future generations would wonder why we did not curtail our production of CO2 all the more if the warming were due to some other reason than that currently identified, especially if it were an unknown one. Regardless of its cause, we do know that cutting our CO2 production would act to combat the phenomenon and should really be given a far higher priority than it currently enjoys. Until Mr Watts, or Professor Salby, or whoever else (but please not Monckton, I am already dangerously close to an overdose of that individual), can identify why the planet is warming if it isn’t due to our production of CO2 (the famous ‘A’ in AGW), then surely the safest course of action is to try to re-establish the conditions that we know produced a reasonably stable temperature in the past. In other words, we should be working really hard to achieve pre-Industrial Revolution CO2 levels. When Mr Watts etc. produce hard, peer-reviewed evidence of what they believe is causing the warming if it is not due to mankind, and, of course, what they recommend the remedial action should be, I see no other option, unless the free market takes precedence over saving lives, of course. Perhaps Mr Watts might like to respond with an explanation as to why he does not support cutting our CO2 production, regardless of what is causing Global Warming, i.e. with or without the 'A'.
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56. electroken at 06:10 AM on 22 April, 2012
    I can see evidence of climate changes where weather patterns have altered from their normalality. I can also understand that there has been evidence of CO2 rises in the past which follow warming trends. The evidence I have seen indicates that the CO2 levels rise after a period of warmer climate. I have seen the curves presented about this and the explanation is that as the seas warm up they release more CO2 as they can no longer hold as much at a higher temperature. I can let all that go and agree to disagree about which comes first, the warming or the CO2. I personally believe that the blame is put on CO2 because that can be taxed. What is never seemingly considered in all this climate debate is the contribution of water vapor. I will not get into a long argument about this, but it is apparant that we are evaporating water in large quantities due to agriculture primarily but also where we are making man-made lakes in deserts and arid regions and filling them by taking water from the aquifers. I read that the large aquifer under the middle usa has dropped 150feet in only 10 years. I read that many years ago now so it cannot have gotten any better I would think. If you know your physics you will appreciate that water requires a considerable amount of energy to evaporate (on the order of approximately 1500 btu/lb I think) and this enourmous amount of water being put into the atmosphere can alter weather patterns and lead to larger and more storms than before. It is happening! I am more critical of lack of thought as to what else might be making us warmer and changing our weather. I am not alone in this thought and there is at least one other person who has compiled a lot of data on this subject. It does not even consider the role of water vapor being put into the upper atmosphere by high altitude jets at the rate of 5 pounds of water vapor for each pound of fuel burned. Please look into it before throwing out the baby with the bath water.
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57. sidd at 06:36 AM on 22 April, 2012
    Mr. electroken writes at 06:10 AM on the 22nd of April, 2012: "...agree to disagree about which comes first, the warming or the CO2. I personally believe that the blame is put on CO2 because that can be taxed." So: No calculation. No citations. Argument from motivations. Statement of personal belief. I do feel honored that you so graciously agree to disagree. "What is never seemingly considered in all this climate debate is the contribution of water vapor. I will not get into a long argument about this, but it is apparant..." It is not at all apparent. Climate scientists are quite aware of the nature of condensible greenhouse gases. Let me put it this way: Consider that little pink unicorns are heating the earth. The earth has a big pool of water on it. In response to the unicorn heating, water vapor will evaporate and amplify the warming. Now imaging that all the unicorns are summarily killed, and the warming stops. Guess what, the earth cools back down, and the water vapor that evaporated earlier rains back out. Water vapor is a feedback, not a forcing. "If you know your physics..." I just might. I do hope that the better part of a decade in grad school, followed by years of physics research might have helped. Now, to drag the conversation back toward topical: Let me ask you something: why do you believe the statements that you made ? what is your level of math training ? have you done any calculations yourself ? do you read the literature ? or are you regurgitating arguments from denialist web sites ? in short, i am trying to discover why you believe untruths on the level of pink unicorns... sidd
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    Moderator Response: Electroken, if you'd like to discuss whether warming or CO2 comes first, do so on the thread CO2 lags temperature--after you read the post there. if you'd like to discuss water vapor more, do so on the thread Water vapor is the most powerful greenhouse gas--after you read the post there.
58. dr2chase at 06:52 AM on 22 April, 2012
    @muoncounter (#39) - I think that means that knowing gross bounds on sensitivity is part of what we are or are not sure of. I agree that we've bounded sensitivity below and probably above at this point, but I think it is relevant as a checklist item, "are we sure of this, and why?" It's probably not a bad idea to push the bounds on what we are or are not sure of; that helps tell you where to look for more information, do more research, or think harder. For example, I am not "certain" that the sea level rise in the next 90 years will necessarily be above half a meter, or below five meters (i.e., loads of uncertainty there). One of those outcomes is really costly. I'm not sure that we'll lose the ability to grow mass quantities of grain here in the US, but I'm not sure that we won't, either.
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59. Killian at 07:26 AM on 22 April, 2012
    How do we know we are right? What, exactly, tells us we aren't? Answer: Nothing. This is literal. There is not a single study out there that in any way invalidates any of the core knowledge of climate science leading to the conclusion - let alone the observable changes! - that anthropogenic climate change is in process, and more advanced than many (publicly) acknowledge. But let us play this game. As pointed out above, we'd have to invalidate great chunks of basic science to deny the research and observations. A corollary of that is, what other areas of science of so-called skeptics deny? None. Only those that blow up their economic desires (climate, peak resources) and their religious beliefs (evolution) get challenged. Why are all other areas of science believable, but not these two? The scientific method is what it is, and is applied with variance in techniques, to all areas of science, but it's invalid in just those areas that are socio-politically conservative? Things that make you go, "Hmmm...!" But, hey, let's just toss out the scientific method. How else do we know? The scenarios created forty years ago (Limits to Growth), and thirty years ago (Hansen, et al. '81-ish), 24 years ago (Hansen, et al, '88-ish) and ever since are indicating, then being validated by, the physical world. if anything, the scenarios have tended strongly to underestimating change than overestimating despite the bleating idiocy that allows some to call this falsification of the scenarios! Now, I'm not a scientist, but consider myself fairly good at analysis, particularly of patterns. While scientists mostly constrain themselves to what they can prove or demonstrate with high **scientific** confidence,individuals such as myself can go straight to risk assessment and call this what it is: a massively dangerous change for humanity and all the rest of the biota on the planet. And,we non-scientists can also step beyond scenarios and talk predictions. I have been saying since 2006-7 that the changes were coming far faster than scientists were saying. That's six years of calling imminent large changes in weather and climate, and being right. This isn't hard. It's all about understanding systems, connections, complexity and bifurcations... along with other stuff, but at the core, that's really all it is. I had an e-mail conversation with a scientist about the clathrates after the 2007 work by Walter, et al., came out about thermokarst lakes. The patterns we were seeing even then made it clear the decomposition of the Arctic had to be far, far faster than thought at the time. It, again, wasn't rocket science, it was merely looking at what was supposed to be happening, then looking at what *was* happening, adding in the background of how non-linear and chaotic systems behave, the speed of change, tipping points, etc., and it was plainly obvious. Yet, the scientist i was e-mailing with, the guys at RealClimate, etc., all held to the decades/centuries standard response. I was scared to death to have a paper published that saw it as I did, but when the projections came out of 80 melt of Arctic Sea ice between 2013 and 2020 came out, I was also elated: Finally! The science was catching up! I'm confident because what is being predicted is coming true, let alone the scenarios being accurate. And, really, all you have to do is open your eyes. Pretty simple. And remember: it's the extremes that will get us, not the averages. We will continue to see massively disruptive events, and they will get far worse long before we reach an average of +2C. This Spring's reverse "Indian Summer" and the subsequent crop losses (95% of grape crop in SW Michigan, e.g.) are just a taste. Let this become (more) normal and food is going to become a big issue in a very short period of time. When the Arctic Sea Ice really does hit as low as 80% mass/area/extent loss it will likely be game over. At that point, only a massive, global shift to localization and sustainability will have any hope of cooling he oceans quickly enough to prevent a clathrate bomb. The fuse is already lit. Reforestation: Can equal 100% of current CO2 emissions. Regenerative Farming/Gardening: Can equal up to 40% of current emissions. So, just two simple changes can get us moving backwards with carbon within five years. Hmmm... The solutions are out there, they are simple, they are doable. They are not tech, they are not greater complexity. They are simple, rich, organic, local. We DO know what is happening, we DO know where we are headed, we DO know the risk assessment. We can keep letting false equivalence and scientific reticence keep us from speaking and acting, or we can bring ourselves back from the brink. Up to you.
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60. kampmannpeine at 08:59 AM on 22 April, 2012
    A simple thing as regards theories and "truth": Einstein said: when I have various choices for a theory then I choose the most simple. Apply that to the problem of Keplerian equations versus Ptolemaeus ... Kepler's equation are elegant an simple compared to the epicycle stuff of the old Greeks ..
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61. kampmannpeine at 09:00 AM on 22 April, 2012
    Thanks for those nice comments ... I will use the ideas in my lectures ...
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62. empirical_bayes at 12:15 PM on 22 April, 2012
    Because the question and the phenomena cannot be argued with the weak devices of words and verbal logic. It demands mathematics.
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63. bill4344 at 14:23 PM on 22 April, 2012
    dikran, caerbannog, Connoiseurs of the true train-wreck should really take time to savour what happens here [HVR* warning] to even one of the faithful where he dares point out that Salby's Emperor is, um, starkers!... *Head-Vice Required.
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64. jyyh at 16:51 PM on 22 April, 2012
    Why Are We Sure We're Right? Well, we can't be absolutely sure we're right but the people who have survived the attack of the Auditors of Reality as has been described in the Book of Blind Io have told us the Roundworld really exists and that life on the Disc is really annoying to them because of the Majjik exerted on it makes the calculations of entropy, entalphy and in fact the all alternative theories of GHE really complicated. Just a presence of one wizzard on an area may increase the heating potential of Swamp Dragons by 10-fold, specially so if they're being chased by trolls, it's lots easier to calculate this with methane and carbon dioxide, they say. I might do this more seriously sometime.
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    Moderator Response: [DB] [GT] New addition to the SkS Moderation Policy. References to Terry Pratchett are ALWAYS Omn Topic.
65. John Russell at 02:07 AM on 23 April, 2012
    Why am I sure I'm right? Well as of this moment I can be completely sure -- though that's not to say contrary evidence might one day make me change my mind (well; we can live in hope). But, if I look at all the various lines of evidence in thousands of papers produced by thousands of climate scientists and the thousands of explanatory blogs written by climate science supporters, then it all adds up to a coherent picture. A picture that's not completely formed and has a few missing pieces -- but is very much hanging together. On the other hand, if I read all the fake sceptic and denial literature I don't see a coherent picture: I see a mish-mash of cherry-picked, discrete examples of evidence, many of which contradict one another. What's more, when I see climate scientists and lay people discussing the evidence, sometimes disagreeing about detail I see that generally they learn from each other in an atmosphere of discovery. On the other hand, with fake sceptics and deniers, I see just people spreading denial memes and failing to argue with one another: if you're in climate denial and you're having a go at 'the team' then you're a good egg. So the answer to the first question is very clear to me.
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66. KeefeandAmanda at 02:11 AM on 23 April, 2012
    Well, when all the causal possibilities except one have been pretty much falsified, by the process of elimination that's pretty darn well close to being sure. Here is what I mean: I like to simplify and generalize things as much as possible when talking to people about global warming, especially when they are fake skeptics. Here is what I say: To simplify and generalize things as much as possible, let's realize that apart from heat from the interior of the planet, there generally are only three possible ways to heat the planet's fluidic system (atmosphere and oceans taken together as a system - see http://en.wikipedia.org/wiki/Fluid_dynamics for an idea of what I mean): (1) More heat falling onto Earth from space (from the sun); (2) more of the heat falling onto Earth being absorbed - that is, decreased albedo or less reflected sunlight; (3) less of the absorbed heat radiating back out into space via increased greenhouse gas activity. (All talk of such things as cosmic rays, clouds, aerosols from volcanic activity or human pollution, etc. is covered by the general case of (2).) Atmospheric heating by either of general cases (1) and (2) alone or together implies that, globally: (A) the nighttime temperature rises slower than the daytime temperature; (B) the arctic temperature rises slower than the equatorial temperature; (C) the winter temperature rises slower than the summer temperature. Atmospheric heating by general case (3) implies that, globally: (D) the nighttime temperature rises faster than the daytime temperature; (E) the arctic temperature rises faster than the equatorial temperature; (C) the winter temperature rises faster than the summer temperature. Guess what has actually has been happening on average over the past several decades? Conditions (D), (E), and (F) happened, the opposite of (A), (B), and (C). Since (1) or (2) alone or taken together implies false conditions, the fake skeptic claim that only one or both of (1) or (2) has been causing the heating - that (3) has had nothing or essentially nothing to do with it - is falsified. By the process of elimination, there has to have been very significant involvement of (3) to result in the heating, an involvement much more significant than the fake skeptics are willing to admit to.
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67. KR at 04:36 AM on 23 April, 2012
    bill - "...take time to savour what happens here [HVR* warning] to even one of the faithful where he dares point out that Salby's Emperor is, um, starkers!..." As someone else who participated in that discussion, noting the concentration adjustment time factors for CO2, I would have to once again quote Nietzsche: "At times one remains faithful to a cause only because its opponents do not cease to be insipid." Quite frankly, if the 'skeptics' had any actual points regarding the science - well, they would make better arguments.
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68. actually thoughtful at 07:37 AM on 23 April, 2012
    The question really drives at what is science? How do we know anything? What we DO know - we know from science. Science tells us AGW is by far the most likely theory. When science tell us a different theory explains AGW (and the chances of this are less than 1%) - then I will "know" that is right.
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69. Doug Hutcheson at 11:37 AM on 23 April, 2012
    bill @ 63, I gave up reading the comments at JoNova, after finding this gem:

    It is probable that oil existed before plant life – that fossils found in coal are merely plant life enveloped in solidified oil.

    And this one:

    “‘controlling the natural flux of CO2 is ... a fool’s errand to try”" How do we get this message into the public domain after so many years of “scientific” indoctrination in schools??

    Sigh.
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70. John Brookes at 22:43 PM on 23 April, 2012
    So I'm a skeptic. I find it hard to believe that warming of 2 or more degrees will happen this century. But that seems to be what the smart people are saying, and you'd be a fool to ignore them and just hope it won't happen. But as with many other commentators here, its the "skeptics" themselves who make me feel more confident that AGW is a problem. The "skeptical" position is totally undermined by their own arguments. Once you've seen a "skeptic" embrace a particularly silly idea (Salby's is just another one), it is very hard to take them seriously on anything else they say. Their weird ideas on economics and government also make it hard to give their views on climate any credence. It is worth noting that extreme environmentalists are the same as "skeptics". They are only too willing to incorporate the latests silly idea into their world view.
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71. Cornelius Breadbasket at 23:06 PM on 23 April, 2012
    Why do I think I’m right? I don’t know if I do. I’m a layperson when it comes to science, so I feel that it is possibly harder for me to ‘know’ I’m right than many others who post here. I apologise if my reasoning and arguments are simplistic, I am not a complex thinker. What does ‘right’ mean? Throughout my life I’ve learned that in order to make informed decisions you have to continue to question everything until you perceive a balance of evidence. ‘Right’ about what? Right that human activity is warming the planet, changing the climate and could be dangerous. The evidence that I have seen and the experts that I trust help me to make decisions about AGW. Again, the following list is extremely simplistic but it is genuinely part of my personal decision-making process. Personal experience:
    • I’ve been a gardener/small farmer for 30 years. Food production is becoming harder because of recent weather pattern changes
    • I live in the UK and we are seeing new species of insects migrating to the UK from southern Europe
    • Occasionally there are Daffodils at Christmas – in my childhood and youth they came in March and April
    • Garden birds are nesting in March instead of April and May
    • There have been more extreme weather events than during my childhood and formative years. We are currently experiencing a drought
    • I have had dramatic personal experience of a near-fatal flooding event in 2007 (I understand that this was a one in a thousand year event. We have had two more similar flooding events in the UK since then)
    • Insurance premiums increasing because of increased flood risk
    • I have seen that human activity can have a detrimental effect on landscapes, levels of pollution and biodiversity so it is probable that human activity has an effect on the atmosphere of a finite planet
    Informed sources I also look to experts to help make informed decisions. This is how I choose the experts that I feel I can trust:
    • People with qualifications in the field in which they speak
    • People who admit if they are wrong and re-evaluate their claims based on evidence
    • People who have access to the latest and most up-to-date equipment and research methods
    • People who are open about any political, corporate or financial motivations that may influence their opinions
    • Those who are not motivated by fame or notoriety
    Using these points as a filter I rule out the opinions of Gore, Michaels, Lovelock, Lindzen, Spencer, Singer, Christy, Watts and Monckton. I rule in the opinions of Mann, Hansen, Briffa, Jones, Trenbeth, Schneider, Schmidt, Alley and Abraham. The balance of my own experience is that the climate is changing and that the world has become more populous and industrialised. The balance of opinion of the experts that I trust is that human activity is warming the planet, causing climate change and is likely to be dangerous. So, in summary, I think I am right because of personal experience combined with the opinions of experienced expert sources in areas in which I am not qualified.
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72. ajki at 03:52 AM on 24 April, 2012
    As to climate questions, especially global climate, I'm not only not qualified, but absolutely unable to gather data, test & qualify, discuss & describe, interpret & model or combine & evaluate within in even one single field of the broad spectre of relevant sciences. This situation is nothing unusual for me - in a highly specialised modern world there are very few areas where I myself have enough knowledge, experience and practice to come by with at least educated guesses. Heck, I can't even repair the damned car anymore because of the load of built-in electronic components today. But I've also learned - as anybody else - to delegate the workload to specialists. And here in Germany, there are a lot of great institutions bound to climate sciences - for decades now. If those "specialists" publish through formal channels and their findings are based on empirical data and their findings have a reasonable and coherent outcome, I trust them. Why shouldn't I? And then it really helps to consider between right and wrong when you permanently find those ad hominem attacks on denier blogs (e.g. calling Drs Rahmstorf and Schellnhuber "... so called climate scientists ..." on EIKE - don't look for it, it's WUWT, only worse).
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73. Chris G at 13:44 PM on 24 April, 2012
    I'm wondering who 'we' are. What's the criterion: Someone who actually does research in the field, or someone who just believes that the majority of scientists are more likely to be correct than the very small minority who say we have nothing to worry about? I mean, for most people, it is an appeal to authority, isn't it? For my part, I can fit the various aspects within the physics, chemistry, statistics, etc. that I learned in school, and I can not fit any argument put up by the opposition. But, while my education is much less than a researcher's, it is also much more than an average layman. How is the average person supposed to know if they don't understand even basic physics? I thank Rob for putting this up, but I am starting to think it really doesn't matter how researchers know. People with a high level of understanding on the subject are a small minority. There are way too many voters who believe whatever sounds good to them, and there are too many people happy to tell them what they want to hear. Who in their right mind would enthusiastically embrace the notion that they have contributed to something which will be detrimental to the well-being of their children? That's what the facts lead to, but given that kind of psychological pressure, it should not be surprising that all sorts of irrational ideas come squirting out of people's minds. It doesn't matter; faced with that awful conclusion, almost anything else is easier to believe.
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74. Fran Barlow at 11:49 AM on 25 April, 2012
    Those interested in supporting Grahame Readfern over at his blog on the Anna Rose v Minchin I can engage in a flawed debate on Climate Change can follow the link to do battle. I've had my say.
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75. Tristan at 21:09 PM on 25 April, 2012
    Cogent and succinct, Fran.
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76. Glenn Tamblyn at 22:27 PM on 25 April, 2012
    Steve Case @33 Sorry about the delay in replying - just in the middle of selling my business and life has been hell Yo asked "Glenn's list is a good one for the basics of the greenhouse effect, but I should like to know if he's sure he's right about the positive feed backs that elevate CO2 Climate Sensitivity from the basic 1.2°C to 3°C or more." I think the ground for thinking that CS is something like this is quite solid, although there is still significant margins on the current estimates.Item 10 on my list about the Clausius-Claperon eqn goes to the heart of this. Warmer air can hold more water vapour. It is often suggested that increased evaporation will produce increeased water vapour levels but actually, in a warmer world, water vapour levels are likely to be higher even without greater evaporation. Put simply, evaporation pumps water vapour into the atmosphere and precipitation pumps it back out again. Water vapour levels will be in long term balance when global evaporation and precipitation rates are qual (obviously at short time scales and regionally this doesn't hold; I am talking more about longer averages) But precipitation needs clouds. No clouds, no rain. And clouds largely only form when water vapour content is close to the saturation level for the atmosphere; when relative humidity is nearly 100%. This is why clouding seeding has never been too successful. If the air temperature is higher, the amount of water vapour needed to reach saturation is higher. And clouds can't form until reaches that level. So evaporation will keep increasing the water vapour content of this warmer air until it does reach saturation so clouds can form. If we could wave a magic wand and instantly increase the air temperature everywhere by 5 Deg C, the most immediate and visible impact that much of the cloud around the world would vanish - re-evaporate back into the air. Only when evaporation has built water vapour levels up higher can cloud formation and precipitation start again. There are obviously local effects, dry air regions etc but this basic property that rain can't happen unless their is enough water vapour in the air is absolutely fundamental science. Thus water vapour MUST producea positive feedback. There are valid questions of how much. Clouds in contrast have both cooling and warming effects, depending on the type of clouds. The net impact is thought to be a slightly positve effect. So for changes in clouds to counteract the definite positive feedback of water vapour, there would need to be not just a change in the total amount of cloud, but a change in the mix of cloud types. No one has put forward a reasonable explanation for why that might happen. Without this, clouds can't counter the positive feedback from water vapour. There is however a whole range of other evidence in support of CS values in the 3 range. This come from a wide range of studies looking at past climates going back centuries, 100's of 1000's of years, Millions and even 100's of millions of years, responses to volcanic eruptions etc. It isn't just climate models predicting CS values of that range, it is physical evidence from past climates. And since temperatures significantly higher than now have actually been the norm for much of the last 1/2 billion years, warming now isn't unusual, unprecedented or unlikely. The climate could quite easily return to a warmer state if we push it that way. Human Civilisation developed in a relatively cool 'Goldilocks' climate.
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77. Glenn Tamblyn at 22:47 PM on 25 April, 2012
    elektron @66 read this earlier post I wrote some time ago here. It discusses how the magnitude of the warming we are experiencing limits the range of possible explanations. Jet exhausts in the Stratosphere are certainly a contribution because water vapour in the stratosphere doesn't get removed from the atmosphere quickly. The stratosphere is also the main location where Methane gets converted to CO2 & Water Vapour. Jet Con-Trails have also been identified as having a small cooling effect as well. The principle reason why evaporation of water from land is only a relatively small component is because evaporation from the oceans is so massive. Also, as I discussed in my previous comment, it isn't necesarily increased evaporation that is the issue. It requires increased temperatures to allow the atmosphere to hold that increased amount of water, otherwise it justs rains out again. Increases of GH gases other than water are needed to cause a warming that allows more water vapour to be held by the atmosphere.
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78. otter17 at 03:07 AM on 26 April, 2012
    Excellent article topic and discussion. My domain is engineering, but I find the mindset that many scientists have to be worth emulating. For me, I have made a habit of re-evaluating my stance every once in a while, realizing that it is a strength, not a weakness. It is good to see the authors here think along the same lines.
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79. RW1 at 08:07 AM on 26 April, 2012
    How do I know I'm right? Very simply. The AGW 3C rise hypothesis requires that watts of GHG 'forcing' have a 3 times greater ability to warm the surface than watts forcing the system from the Sun. Give that each incremental watt from the Sun causes proportionally less and less warming in the system, and a watt of GHG 'forcing' can only do the same amount of work as a watt of solar forcing, Occam's razor prevails.
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80. RW1 at 08:23 AM on 26 April, 2012
    Actually, if anything, the ability of a watt of incremental GHG 'forcing' to warm the surface would be a little less than solar because some of the internal energy would have to be expended to reorganize the temperature structure of the atmosphere.
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81. scaddenp at 08:59 AM on 26 April, 2012
    Sigh, numerous people have tried to help you see this particular error, RW1, but since you wont do your homework, I doubt it is worth trying. Just for the record, the efficacy of the various forcings are approximately the same (see here and Hansen 2005. Climate science agrees solar and CO2 forcing are about the same. It's your excessive linearization that makes you think that CO2 is required to be 3 times solar.
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82. RW1 at 09:13 AM on 26 April, 2012
    scaddenp (RE: 81), "Climate science agrees solar and CO2 forcing are about the same. It's your excessive linearization that makes you think that CO2 is required to be 3 times solar." Actually, no - it's the exact opposite. It's the non-linearity of the system's response to the forcing of the Sun that contradicts GHG 'forcing' being 3 times that of solar.
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83. KR at 09:23 AM on 26 April, 2012
    RW1 - "It's the non-linearity of the system's response to the forcing of the Sun that contradicts GHG 'forcing' being 3 times that of solar." Nobody claims that GHG forcing efficacy is 3x that of solar. They are roughly the same according to current data, with long-lived GHG's perhaps 10-15% more effective than solar due to where the energy goes. But if the solar input increased by 3.7 W/m^2 (as per a CO2 doubling), we would still expect ~3C of warming total.
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    Moderator Response: [DB] If RW1 persists in his refusal to understand this point, then he will have to take it to a more appropriate thread. This will be about the 4th go-round for him, if so.
84. scaddenp at 10:36 AM on 26 April, 2012
    "excessive linearization" is inappropriate attempts to linearize a non-linear system. That's the only way to conclude "The AGW 3C rise hypothesis requires that watts of GHG 'forcing' have a 3 times greater ability to warm the surface than watts forcing the system from the Sun." As KR's plot show, AGW requires no such thing.
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85. Tom Curtis at 10:38 AM on 26 April, 2012
    RW1's bizarre claims assume that solar forcing results in no feedback response. That is, if the world's oceans are heated by 1 degree C by an increased GHG concentration, that will result in increased evaporation and an increase in absolute humidity (and hence a water vapour feedback), but that an increased temperature of the same proportion brought about by a brighter sun will not increase evaporation at all, nor melt any snow, or in any other way have feedbacks. RW1 can only attribute this view to climate scientists because, as always, he operates in complete disregard of what climate scientists actually say. As KR ably demonstrated, climate scientists make no such assumption. Indeed, in the only direct comparison in the chart above, CO2 forcing is around 10% more effective than solar forcing, and WMGHGs in general are 20% more effective - a far cry from the 300% claimed by RW1. These small differences are because the CO2 GHE and solar warming have their strongest effects at different latitudes, and at different times of the day and year. Still more bizarre is RW1's claim that CO2 should result in less warming because of the energy needed to modify the internal energy structure of the atmosphere. What is bizarre here is that inside the troposphere, there is no significant difference in the change in temperature structure with time under GHG and solar warming. But solar warming heats the stratosphere, while increased GHG cools it - so as usual, RW1 gets the science completely backwards.
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    Moderator Response: [DB] Please take this discussion to one of the more appropriate threads. RW1 must perforce translate everything climate related into electrical engineering terms instead of learning the science in question; a very slogging approach, detrimental to thread health.
86. RW1 at 12:05 PM on 26 April, 2012
    Which thread, DB? How about suggesting a thread before deleting comments?
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87. RW1 at 12:13 PM on 26 April, 2012
    Can you move my deleted comments to an appropriate thread of your choice? If Tom wishes, he can continue the discussion there.
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88. Bob Lacatena at 13:49 PM on 26 April, 2012
    RW1, I suggest you take your comment to the climate sensitivity thread.
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89. RW1 at 03:54 AM on 27 April, 2012
    Sphaerica, OK, sounds good. Moderators, can you move my deleted comments to the climate sensivity thread? I would do it myself, but I didn't copy them and don't have them anymore. Thank You.
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