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Comments 121901 to 121950:

121901. KR at 05:37 AM on 27 March 2010
        A peer-reviewed response to McLean's El Nino paper
        Well, chris, I was trying to be nice. I agree - the bandpass operator they use is pretty worthless, as shown by getting equal matches to randomly generated data; I just wanted to point out that big internal consistency flaw between their paper and their (unjustified) conclusions.
121902. KR at 05:32 AM on 27 March 2010
        Is CO2 a pollutant?
        suibhne, also look at this, which is an excellent explanation of what G&T's attempted equivalence of convective greenhouse heating with radiative greenhouse gas heating really means.
121903. KR at 05:28 AM on 27 March 2010
        Is CO2 a pollutant?
        suibhne, I read the G&T paper. I've rarely seen a worse article, EVER. I would suggest you look at some of the responses to that which have been linked to from this blog. G&T pose a strawman argument, that the greenhouse effect (radiative heating by greenhouse gasses in the atmosphere 55 pages in their paper) is not the same mechanism as surface greenhouses (blocking convection/conduction heat exchanges, 20 pages). This gets covered in the first two minutes of review in any thermodynamics discussion on the topic - G&T claim this these aren't equivalent, therefore greenhouse gasses don't hold heat, which is bull****. The surface of the earth would be ~33C colder if they didn't. Nobody argues that these two mechanisms hold heat the same way, just that they are similar in effect (warming things up). Side note - they also seem to claim that the IPCC came up with radiative forcing and radiative equilibrium. They're a bit off with that statement; I believe that dates to 1791. Please read that, the references are excellent. G&T misderive path length intercepts for IR and CO2, derive wavelength dependent energy retention for glass but then claim that can't possibly work for CO2, contradicting themselves, etc. There are (by my count) about 2 misstatements per page. The core of their argument, described in regards to a car heating in the sun, is "Conduction, condensation and radiation, which slow down the rise in temperature, work practically the same inside and outside the car. Therefore, the only possible reason for a difference in final temperatures must be convection...". G&T essentially argue that radiation would rapidly equalize temperatures. This means that they haven't done their math! Total energy into the atmosphere (solar plasma emission spectra) warms the surface of the earth, which radiates a different spectra (thermal IR) back up. Increasing CO2 blocks part of this thermal spectra. For the energy output to balance the solar input in a steady state condition, the entire thermal spectra must increase in intensity to counter the CO2 blockage, which means that energy will accumulate (rising temperature) until the sum spectral energies in/out are equivalent. This is pretty basic; G&T either don't understand radiation equilibrium or choose to ignore it. The paper is worthless. Read this, this, and finally this for some useful descriptions of radiative equilibrium. There are some excellent thermodymanics links from those pages as well.
121904. chris at 04:58 AM on 27 March 2010
        A peer-reviewed response to McLean's El Nino paper
        Ned, McLean et al neglected to reproduce this part of the review:

        Accept pending major changes (mainly in style not scientific comment) The real mystery here, of course, is how the McLean et al. paper ever made it into JGR. How that happened, I have no idea. I can't see it ever getting published through J Climate. The analyses in McLean et al. are among the worst I have seen in the climate literature. The paper is also a poorly guised attack on the integrity of the climate community, and I guess that is why Foster et al. have taken the energy to contradict its findings. So the current paper (Foster et al.) should certainly be accepted. Someone needs to address the science in the McLean et al paper in the peer-reviewed literature. But the current paper could be - and should be - done better. That's why I am suggesting major changes before the paper is accepted. All of my suggestions have to do more with the tone and framing of the current paper, rather than its content.

        An account can be found in RabettRun
121905. Ned at 04:39 AM on 27 March 2010
        Is the science settled?
        Oh, dear, Chris. Sorry about that. Looks like we were responding simultaneously. Chris writes: Therefore something's wrong with your argument. Can you spot it? I'm afraid I might have given a small hint there. :-)
121906. Ned at 04:36 AM on 27 March 2010
        Is the science settled?
        Berényi Péter, I don't think you understand the mathematics of feedbacks. You might want to reread the comment by Chris above. A positive feedback does not imply a "runaway" system unless the feedback coefficient f is >= 1. For positive feedbacks 0 < f < 1, the total increase from the feedback will be 1/(1-f), as Chris says. As you yourself said, It is not climate science, not even physics. Just plain old math. However, it's important to have the math correct. This is a common mistake -- many people assume that a positive feedback must increase without bound.
121907. shopa at 04:36 AM on 27 March 2010
        How you can support Skeptical Science
        John, you are doing a great job. I have started a chain letter to get readers for you in the USA. To readers: I have invented a new way to fight bushfires. www.electric-fluid-pipeline.com Please help me get some attention from the Australian authorities.
121908. chris at 04:32 AM on 27 March 2010
        Is the science settled?
        Berényi Péter at 03:45 AM on 27 March, 2010 Don't think anyone's going to fall for that BP! Since the water vapour response is positive (after all we can measure the increased water vapour concentration in the atmosphere as a result of warming over the last 30-odd years, pretty much as predicted), and we haven't had your scary runaway scenario, it follows that the latter isn't "inevitable" as you assert. Therefore something's wrong with your argument. Can you spot it?
121909. Ned at 04:13 AM on 27 March 2010
        CO2 was higher in the past
        Thanks, muoncounter. Also, re: Please note that I accidentally italicized the last sentence ("We don't see...") in #10. That was my statement and not part of the referenced article. Yes ... and I solved that by inserting a "/i" tag (in brackets) at the beginning of my comment. :-)
121910. Berényi Péter at 03:45 AM on 27 March 2010
        Is the science settled?
        Ned, folks could use some common sense, I guess. If water vapor feedback on CO₂ warming is positive, then it is positive on any kind of warming, right? Even on warming caused by some random increase of humidity. At this point one can safely forget about carbon dioxide and start worrying about dihydrogen monoxide pollution. For we have an almost infinite supply of the liquid form of this stuff with an open surface exceeding 3.6 × 10¹⁴ m². As temperature gets higher, the Clausius–Clapeyron relation ensures ever higher rates of evaporation. Or does it? The final state is a H₂O atmosphere with trace amounts of nitrogen and oxygen. Surface pressure is 2.6 × 10⁷ Pa, temperature above 600 K. It is called a runaway greenhouse. Can last for some ten million years, molecules split by UV in upper atmosphere, hydogen escapes to space, are left with plenty of oxygen but no water. Limestone releases CO₂ slowly, Earth is transformed to hell. Somehow it never happens. Why? Because dihydrogen monoxide feedback is not positive. If it would be positive, the scenario described above is inevitable. It is not climate science, not even physics. Just plain old math. Plus the empirical fact we are still alive. Water feedback should be slightly negative, very close to neutral. Greenhose effect is saturated. So. The one million dollar question to climate scientists is not whether water vapor feedback is positive or negative, but how this negative feedback loop works?
121911. muoncounter at 03:38 AM on 27 March 2010
        CO2 was higher in the past
        Ned, Those mechanisms are critical to the argument over "high CO2 and glaciation=No". It is certainly clear that widespread carbonate deposition takes up lots of atmospheric CO2, but whether that alone causes an ice age isn't clearly established. It is also clear that the graph of CO2 levels taken from a denialist website, posted above (#6), doesn't take a short-term drop in CO2 due to perfectly valid geological mechanism into account. I have some difficulty with the mechanisms in the "Mountains that froze the world" article John references at the top of this thread. For one thing, the Appalachians weren't all done in the late Ordovician -- it took another 100 MY or so until the Alleghenian Orogeny was complete. The image below is the mid-Ordovician southern ocean: -- source All that light blue is shallow sea -- mostly between 10N and 30S latitude -- perfect environment for carbonate deposition from marine organisms. For another, the idea that Sr86 in Nevada is runoff from the proto-Appalachians just doesn't seem right -- on the map above, Nevada is on the 'north coast' of Laurentia, while the emerging Appalachians are on the 'south coast'. Other mechanisms abound in the literature, from a mega-volcano to a gamma-ray burst. From another key paper on this subject, "the waxing and waning of ice sheets during the Late Ordovician were very sensitive to changes in atmospheric pCO2 and orbital forcing at the obliquity time scale (30–40 k.y.)" I've even seen one author who suggests that the concentration of continental land masses at the south pole would perturb the earth's orbit -- but that's a much longer-time scale event. Please note that I accidentally italicized the last sentence ("We don't see...") in #10. That was my statement and not part of the referenced article.
121912. Ned at 03:01 AM on 27 March 2010
        A peer-reviewed response to McLean's El Nino paper
        HumanityRules writes: Here is Mclean et als reply to the Foster comment. Warning: this is not peer-reviewed (this becomes obvious very quickly). It also contains reference to the climategate emails which I know some people are a little sensitive about. Hmmm. It looks like McLean et al. went through the CRU emails and found the anonymous reviews of the Foster et al. comment. They quote a couple of sentences allegedly from one of the reviews ("But as it is written, the current paper almost stoops to the level of 'blog diatribe'. The current paper does not read like a peer-reviewed journal article. The tone is sometimes dramatic and sometimes accusatory. It is inconsistent with the language one normally encounters in the objectively-based, peer-reviewed literature.") I'm a bit disturbed by the idea of going through someone's email to find and selectively quote comments from the peer review process, which is supposed to be anonymous and confidential. If McLean et al. are going to do that, I think that they ought to make the reviews of their own (rejected) comment similarly public. And in both cases they ought to show the full text of all the reviews, not selectively chosen snippets from one review. What else did this reviewer have to say about the Foster et al. comment, besides a couple of sentences complaining about the tone? It's hard not to suspect that if there had been any more substantial criticisms, McLean et al. would have quoted those parts, rather than the fairly mild complaint they did quote.
121913. Ned at 01:38 AM on 27 March 2010
        Is the science settled?
        Berényi Péter, I don't think we're going to throw out Clausius–Clapeyron any time soon. The evidence for a positive water vapor feedback is discussed in some detail on John's page Water vapor is the most powerful greenhouse gas. This can be easily seen over the long term, but it also manifests itself via interannual variability e.g. following the eruption of Mt Pinatubo. I think Solomon et al. 2010 does a nice job of discussing both the long-term role of water vapor as a positive feedback and its shorter-term role in sub-decadal scale variability.
121914. Ken Lambert at 01:04 AM on 27 March 2010
        Is the science settled?
        Profmandia #7, #25, Ned#66 BP#78 Glad you had a look at the Trenberth paper because I find the overall calculation of the Earth's energy imbalance the most relevant measure of potential warming or cooling. Dr Trenberth's paper estimates that the net overall imbalance is +0.9W/sq.m from net radiative effects which equals 145E20 Joules/year. He can only account for about 0.55W/sq.m (about 80E20 Joules/year)in the energy budget for warming oceans, melting ice, warming land etc. He muses over whether the rest is hidden in the oceans below 2000m (recently found in part by von Schukmann but disputed by BP and at variance with several other ocean heat analyses) Within the 0.9W/sq.m imbalance is embedded the climate reponses from Fig4 of Dr Trenberth's paper. The radiative feedback from increasing Earth's temperature of -2.8W/sq.m is based on Stefan-Boltzman Eqan for 255degK and a surface temperature rise of 0.75 degK which seems to apply faily well to the troposphere for the planet above the 'equilibrium temperature' of pre-industrial times. The critical point is what will be the negative radiative feedback for the postulated 3degK rise in surface temperature (doubling of CO2) when applied to Fig 4 of Dr Trenberth's paper where a doubling of CO2 would by IPCC formula increase CO2 radiative forcing to 3.7W/sq.m and other GHG forcings by unknown amounts. The key to this is what portion of the 3degK rise also applies to the troposphere and what will be the increase in the Earth's overall OLR and 'equilibrium temperature'. Humidity and lapse rate are critical parameters around which there is much discussion and uncertainty. Your thoughts gentlemen?
121915. Berényi Péter at 01:00 AM on 27 March 2010
        Is the science settled?
        #79 Ned at 21:56 PM on 26 March, 2010 "What is the "it" in that sentence?" The sign of the water vapor feedback loop, of course. There is a rather strong positive feedback if we keep relative humidity constant on all levels (as it is routinely done in computational models of climate). Whether Mother Nature complies with this requirement is not known.
121916. Christopher Fraser at 00:56 AM on 27 March 2010
        Better to adapt than mitigate
        The Stern Review on the Economics of Climate Change, a 700-page report commissioned by British Government released October 30, 2006, concluded that the benefits of strong, early action on climate change considerably outweigh the costs.
121917. James Wight at 00:35 AM on 27 March 2010
        It's a 1500 year cycle
        John, I've been reading through Motl's rebuttals to your counterarguments, and I think he does have a point about this one. The title "It's just a natural cycle" implies that the page discusses natural climate cycles in general (including solar cycles, orbital cycles, etc). But your response only deals with the claim that we're experiencing something analogous to a Dansgaard-Oeschger event. Thus the title is a bit of an oversell.
        Response: I know, this argument started as a focus on the 1500 year cycle but when I started the Global Warming Links directory, I splintered it off into the more general natural cycle and the more specific 1500 year cycle. But I haven't got around to answering the more general argument. Problem is people have already started adding links to the 1500 year cycle argument so I can't go back to the way it was. Long story short, I painted myself into a corner with my argument structure and the only way out is to find the time to write detailed rebuttals to both. Okay, now where is that time, I know I left it around somewhere...
121918. PatriciaW at 00:06 AM on 27 March 2010
        How you can support Skeptical Science
        I got this message via email and I want to comment that just copying and pasting content from a website to an email message does not work properly. For example the Donate button is not visible, there is no left margin, and lots of characters (Â) are inserted which make it hard to read.
121919. JMurphy at 00:02 AM on 27 March 2010
        What CO2 level would cause the Greenland ice sheet to collapse?
        Ned wrote : "I do not understand why you [GALLOPINGCAMEL] persist in accusing the honest, hardworking scientists of NOAA and NASA of "throwing away data" that they were never given in the first place ... particularly when many different, independent analyses of the data show there is no effect on the end result." For the very same reason that he/she keeps repeating things like : 'The idea that humans are a significant factor in raising global temperatures rests on a very shaky foundation as "Climategate" has shown.' I.E. A few emails/files (none of which actually relate to the science of AGW, unless you believe in cherry-picking words and quotes) are enough for some to carry on denying. 'Unless better evidence is presented I will continue to believe that natural factors dominate.' I.E. With reference to the previous excuse : 'I don't want to accept AGW and will use any straws to clutch at.' 'The "Copenhagen Diagnosis" mentioned at the top of this thread encapsulates the IPCC's over reaching and exaggeration of mankind's influence.' I.E. 'I don't understand/want to wilfully misinterpret the IPCC and what they do and don't do..because I don't want to accept AGW.' 'This is what I call the "Catastrophe de Jour" approach which has damaged the IPCC's credibility beyond repair.' I.E. 'I must join in with those who want to destroy the credibility of the IPCC and we will use any small errors to try to do so; or, at least, to make sure that we can justify our denial of AGW.' 'The IPCC's Alarmist predictions for 2100 depend on climate models (GCMs) and Michael Mann's adherents who cling to tree ring temperature proxies.' I.E. The conservative projections based on GCM and AOGCM models from 10 different countries are, supposedly, all based on Michael Mann and his friends. Hmm. And, supposedly, they are the only ones using tree-ring temperature proxies. Hmm 'One of the many scientists who doubt mankind's ability to affect climate is Roy Spencer:' I.E. One of the very few, but a trusted expert to those who wish to clutch at straws and deny. And one who is presently struggling to explain the high UAH anomalies without reference to AGW. All the statements are trying to justify denial, and neither facts, figures nor reality will be allowed to get in the way of that. That means constant repetition, ignoring others, repetition, repetition, etc., etc.
121920. Ned at 23:29 PM on 26 March 2010
        CO2 was higher in the past
        muoncounter: Thanks for the link to that Villas et al. 2002 paper. That's really neat. They claim that marine carbonate deposition sequestered a mass of carbon equivalent to 350 times the current quantity of atmospheric CO2! I like their explanation of the mechanisms for both the onset and termination of glaciation.
121921. Ned at 23:14 PM on 26 March 2010
        Water vapor is the most powerful greenhouse gas
        Thanks for the comment, Bob Close. First, on the very narrow point of CO2 vs water vapor: As a thought experiment, imagine that you could somehow remove all the water vapor from the atmosphere, and prevent any more water from evaporating into the atmosphere (but you keep CO2 constant). Now, alternatively, imagine that you removed all the CO2 from the atmosphere, but kept water vapor constant. (Yes, both these alternatives are physically impossible on our world, but use your imagination). The world with no water vapor (but normal CO2) would get much colder than the world with no CO2 (but normal water vapor). So in that sense, you could say that "water vapor is more important than CO2 in warming the planet". However, neither of those is a realistic scenario. In the real world, we are doubling CO2 concentration. This has the effect of warming the planet somewhat. Water vapor then acts as a feedback, increasing the warming started by CO2. So we end up with our natural base temperature (t0) plus some new warming from CO2 (dt1) plus some additional new warming from the water vapor feedback (dt2). But in terms of assigning responsibility for that warming ("whodunit?") ... both dt1 and dt2 are a result of the increase in CO2. If we hadn't burned any coal or oil, we would still be at t0. The same would be true if there were some other event that caused warming (or cooling). For example, 65 million years ago a bolide impact on the Yucatan peninsula injected a lot of dust, aerosols, etc. into the stratosphere, which cooled the planet, which in turn reduced the amount of water vapor, which cooled the planet further. None of that cooling would have happened without the bolide impact, so even though some of the cooling involved water vapor, we still would say that all of the cooling was caused by the impact event. That initial cooling was followed by a rapid and extreme warming, caused first by CO and other shorter-lived greenhouse gases, then by CO2 which lasted for many centuries. Much of this new carbon came from the carbonate rocks that were vaporized at the impact site, injecting lots of carbon into the atmosphere. Once again, this warming was amplified by the water vapor feedback, but none of it would have occurred without the presence of CO, CO2, etc. So on both the downswing and the upswing in temperatures, water vapor acts as a feedback amplifying the change in temperature that is created by some other forcing (greenhouse gases, aerosols, solar variations, etc.)
121922. Peter Hogarth at 22:59 PM on 26 March 2010
        Visual depictions of Sea Level Rise
        Berényi Péter at 21:33 PM on 25 March, 2010 I can only suggest your skepticism about GPS is groundless and would be quite worrying to the surveying/military/geodetics community world wide. Please think about the implications. You should re-read your original reference from Ekman 2000, chapter 4 about the then emerging science of vertical GPS measurements and then update it by 10 years by reading the references I and others have supplied, and continuing with your online course. Your comments about “same story” indicate that you have some belief system against AGW which you are using here to discredit high precision geodesy and GPS. This is not evidence based. You have also seem to have confused differences between Geoid and real Earths surface, (which I agree can be very large), and the absolute measurement error in these differences, which is small. I have first hand experience of modern precision GPS base stations as used for Real Time Kinematic work, such as vessel positioning and real time tidal or even absolute heave corrections of vessel motion. If I place such a system on the Earths surface, turn it on, and then look at the diagnostics, I can see the RMS vertical error gradually reduce and settle over a few minutes to cm level or better. This is reported as a difference to geoid measurement (WGS84 usually) but is ultimately referenced to the ITRF Geocentric frame and GPS orbital parameters as already discussed at length. The Geoid is merely a useful tool (for charting etc). Local chart vertical datums are another story altogether! I appreciate you are learning about Geodesy, but a learner should be cautious about making sweeping generalizations based on casual reading. The following is a practical short introductory guide to real world height measurement, and it is already slightly dated as the technology advances rapidly: Heighting with GPS: Possibilities and limitations. The section on manufacturers quoted accuracy should be noted. These are real systems in everyday use. I can supply more detailed references if you wish, but please take time to absorb first and comment later? I have designed non-GPS cm level long range precision positioning/tracking systems down to component level, and these sometimes rely on GPS for absolute accuracy and repeatability over long periods so I have some hard won knowledge of many of the issues I am trying to explain. I still do not consider myself an expert, though I hope you realise that I answer your points constructively with science modulated by rational thought. If I am allowed an off topic comment your conclusions on GPS are indeed “something completely different!”
121923. Ned at 22:41 PM on 26 March 2010
        What CO2 level would cause the Greenland ice sheet to collapse?
        gallopingcamel writes: Yes, I find the prospect of a cooler world much more scary than a warmer one. Perhaps, but the former isn't a realistic danger while the latter is. You might also find the prospect of being chased down Main Street by a hungry T.Rex "much more scary" than the prospect of being killed in an auto accident on Main Street ... but which eventuality is it worth expending effort to prevent? In addition, gallopingcamel writes: On the weather station drop off issue, nobody has addressed my question. How can you justify throwing away most of the data? Yes this has been addressed repeatedly and very specifically. You simply keep ignoring the answers. In very plain terms: No data are being "thrown away." Neither NASA nor NOAA are "eliminating" weather stations -- they use the data that are provided to GHCN by participating national meteorological programs in other countries, and in some cases those stations are dropped by their home countries or there are delays in reporting. For example, with Canada, there are many more stations with data currently through 2008 which presumably will be providing updated data at some point. If you have a problem with this, complain to Canada, not to NASA or NOAA. I do not understand why you persist in accusing the honest, hardworking scientists of NOAA and NASA of "throwing away data" that they were never given in the first place ... particularly when many different, independent analyses of the data show there is no effect on the end result.
121924. James Wight at 22:35 PM on 26 March 2010
        The Dunning-Kruger effect and the climate debate
        I found the information on this page, regarding global vs Mauna Loa CO2, actually more useful than that on the "CO2 measurements are suspect" page. Perhaps you might consider copying it there? I think there is also material here for a potential response to "Mauna Loa is a volcano".
        Response: James, I like your thinking - you have a knack for identifying content from one part of my site that is useful elsewhere. Kind of like "renewable content" for "sustainable blogging". I've just added the 104th skeptic argument, "Mauna Loa is a volcano". Will probably flesh it out further with more info on how they account for the volcano CO2. I've also shamelessly copied the Mauna Loa content to the "CO2 measurements are suspect" page. When I get the time, I'll reshape both contents to make them more distinct from each other.
121925. Ned at 22:23 PM on 26 March 2010
        Is the science settled?
        RSVP writes: Considering that the Moon's temperature goes from 123 C down to -233 yields a median of -55C, telling you that -55 C is where temperatures on the Earth would tend to go in the absence of its atmosphere. So if temperature holds roughly around 14 C (as it does on Earth), this can be attributed to all "greenhouse" effects combined. This is more or less right. The Earth has a higher albedo than the Moon, so with no greenhouse effect the Earth would actually be a bit cooler than the Moon. You're right that this temperature differential is proof of the existence of the greenhouse effect (which should go without saying, but someone keeps disbelieving it over in this other thread) and that it's due to the combination of all greenhouse gases, not just CO2 (mostly water vapor in fact). So that's all well and good. However, RSVP continues: My point being that if anything, for Earth, there is a natural tendency towards cooling... NOT warming. At first I was confused by this, but I think I understand what you mean. We need CO2 to keep the Earth from freezing over, right? Of course, too much CO2 would be unpleasant (cf Venus). For the foreseeable future, though, there is no physical mechanism that could either eliminate the greenhouse effect and freeze us, or create a runaway greenhouse and broil us. Whew! Insofar as there is a long-term natural trend, there are two things to keep in mind: (1) On a timescale of hundreds of millions of years, the sun is getting brighter, which would naturally tend to cause the Earth to heat up (and eventually this will become unstoppable). (2) On the other hand, on the same timescale, CO2 is being removed from the atmosphere and sequestered in carbonate rocks, reducing the greenhouse effect and cooling the planet. So far, over the long term (say, the Phanerozoic Era) the Earth's temperature has generally cooled, meaning that (2) has had a bigger impact than (1). Of course, there's a lower bound below which CO2 can't go, and at some point in the distant future the increasing irradiance will swing the thermostat back towards "broil"....) However, that's all pretty much irrelevant on the timescales we care about (tens, hundreds, thousands, or even millions of years). Right now there's no danger of an abrupt decrease in the greenhouse effect. Instead, the danger is entirely on the "warm" side, especially if we keep burning coal.
121926. Ned at 21:56 PM on 26 March 2010
        Is the science settled?
        Berényi Péter writes: "It depends on [...]" What is the "it" in that sentence?
121927. LauraM at 21:55 PM on 26 March 2010
        How you can support Skeptical Science
        I just read Lubos Motl's critique. If that's the best proofreading of the arguments out there, then I say you've done very well indeed. Although, it is obvious he didn't even bother with the expanded links for quite a number of them. "He apparently thinks that the more convoluted chain of arguments he constructs, the more likely it will become." This applies to LM perfectly.
121928. Philippe Chantreau at 19:10 PM on 26 March 2010
        What CO2 level would cause the Greenland ice sheet to collapse?
        Yet the prospect of a cooler world is both less likely and a lot more remote in time. Milankovitch cycles won't bring glaciation until 10s of thousands of years from now, way more time than civilization has existed. It is not assured that Humans will still be around by then. If they are, I'd like to think that they'll be able to deal with it with science and technologies that were tens of thousands of years in the making. You are entitled to your opinion, but I do not find it to be based on an objective assessment of the existing science and neither is Roy Spencer's opinion. He has demonstrated that through many of his writings and a few blunders too, not the least being related to his own UAH erroneous data, which had to be corrected by others. Unlike his blog posts or opinion pieces, Spencer's record of scientific publications does little (if anything) to undermine the consensus model of Earth' climate. I am unimpressed.
121929. Bob Close at 18:29 PM on 26 March 2010
        Water vapor is the most powerful greenhouse gas
        Good discussion guys! It appears from the comments in general and reading of various paper quoted innthe Arguements,that the critical longer term measurements behind the IPCC consensus understanding of the CO2 forcing and amplification of the dominant water vapour greenhouse effect and feeed backs are not yet available. So although many suspect or actually believe that CO2 has a strong influence on pushing higher atmospheric temperatures, we dont actually know this to be true as a scientific fact. Arguements were made that increased CO2 has caused a little warming which then causes water vapour increases that sustains and amplifies the warming. But surely as Mizimi has rightly emphasised in many ways, water vapour is the dominant GHG as part of the natural evaporative cycle, so it's always been operating and the anthropogenic CO2 increase has just caused some minor additional warming! How does one differentiate the various contributions to GW? Fundimentally then what is the hard proof that CO2 is the dominant factor in GW?, leaving aside model driven assertions that are by default somewhat suspect because factors chosen or their levels may not be represenative of the real complexities involved. I have read the Carbon isotope proposal showing the increased carbon in CO2 mostly comes from burning fossil fuels-and that seems reasonable, but doesn't in itself prove AGW. Climatologists may be sure that their data tells the story well enough, but so far it does not convince me, though I admit to being worried by the evident belief expressed by many authors. However, asserting that CO2 must be the main cause of AGW because nothing else fits the bill- is not geood enough! The science on this must be more clear cut and definitive than at present, especially when major global policy affecting future world economic growth and energy use is at stake.
121930. Berényi Péter at 17:43 PM on 26 March 2010
        Is the science settled?
        #66 Ned at 06:29 AM on 26 March, 2010 "water vapor acts as a feedback, amplifying the forcing from CO2" It depends on global upper troposphere average log absolute humidity trend, which is unknown. Radiosonde balloon measurements indicate a decreasing trend in absolute value, but are questioned. Remote sensing (satellites) is not quite up to the task yet either. Both spectral and vertical resolution are poor, humidity reconstructions are based on sophisticated model calculations, their validity depends on hidden assumptions.
121931. RSVP at 17:41 PM on 26 March 2010
        Is the science settled?
        Thank you Marcel Bokstedt for the reply to the question..."why does Earth's average temperature happen to oscillate about 14 C (or whatever the number happens to be)?" I dont know if it takes so much science or just plain common sense. Considering that the Moon's temperature goes from 123 C down to -233 yields a median of -55C, telling you that -55 C is where temperatures on the Earth would tend to go in the absence of its atmosphere. So if temperature holds roughly around 14 C (as it does on Earth), this can be attributed to all "greenhouse" effects combined. My point being that if anything, for Earth, there is a natural tendency towards cooling... NOT warming. The Earth's temperature is not free floating but "grounded" in a value that is generally driven by its distance from the Sun, and that temperature is much lower than what we are used to. Also, as I tried to say before, graphs such as Figure 2 above, or that which Ned posted, tell you nothing about where temperatures should end up, however they do make an assumption of water being in specific state, (i.e., slightly above its triple point).
121932. gallopingcamel at 16:27 PM on 26 March 2010
        What CO2 level would cause the Greenland ice sheet to collapse?
        Philippe Chantreau (#60), Guilty as charged! Yes, I find the prospect of a cooler world much more scary than a warmer one. When populations are stressed they are more prone to disease be it the Black Death, Malaria or a 'flu pandemic.
121933. gallopingcamel at 15:54 PM on 26 March 2010
        What CO2 level would cause the Greenland ice sheet to collapse?
        scaddenp (#59), The idea that humans are a significant factor in raising global temperatures rests on a very shaky foundation as "Climategate" has shown. Unless better evidence is presented I will continue to believe that natural factors dominate. The "Copenhagen Diagnosis" mentioned at the top of this thread encapsulates the IPCC's over reaching and exaggeration of mankind's influence. This is what I call the "Catastrophe de Jour" approach which has damaged the IPCC's credibility beyond repair. The IPCC's Alarmist predictions for 2100 depend on climate models (GCMs) and Michael Mann's adherents who cling to tree ring temperature proxies. One of the many scientists who doubt mankind's ability to affect climate is Roy Spencer: QUOTE There is no question that great progress has been made in climate modeling. I consider computer modeling to be an absolutely essential part of climate research. After all, without running numbers through physical equations in a theoretically-based model, you really can not claim that you understand very much about how climate works. But given all of the remaining uncertainties, I do not believe we can determine — with any objective level of confidence — whether any of the current model projections of future warming can be believed. Any scientist who claims otherwise either has political or other non-scientific motivations, or they are simply being sloppy. UNQUOTE For more information check out: http://www.drroyspencer.com/ On the weather station drop off issue, nobody has addressed my question. How can you justify throwing away most of the data? In my business there are thousands of scintillation detectors counting energetic photons. We could have saved millions of dollars by dispensing with 80% of the detectors but instead we squirelled away money to buy more!
121934. Philippe Chantreau at 15:39 PM on 26 March 2010
        What CO2 level would cause the Greenland ice sheet to collapse?
        Gallopingcamel, you are sliding toward irrationality and, well, alarmism, with your post #58. Let's not oversimplify things, shall we? Pestilence: Yersinia Pestis multiply in the digestive tracts of fleas, whose blood diet leads to fibrin plug obstructions. The fleas become active above 10 degC. Warmer spring temperatures and wetter summers lead to greater incidence of the disease. http://www.pnas.org/content/103/35/13110.abstract The pestilence of the Black Death is not a companion of cold times. It is interesting to note that wet summers, which tend to be have less very hot days, are especially conducive to greater rates of infections, since the fibrin plugs dissolve above 27.5 degC, temp less likely to be reached consistently for a number of days in a wet summer. As for famine, the potato blight has made a comeback recently, and has been associated with the hairy nightshade, which is well suited to benefit from a longer growing season too: http://www.sciencedaily.com/releases/2007/01/070102132649.htm http://www.jstor.org/pss/4046887
121935. Philippe Chantreau at 14:40 PM on 26 March 2010
        Is the science settled?
        Marcus, short answer: better but nowhere near where they could be. Truth is, the US wastes a lot of energy. The electrical grid is also a significant problem. Plethoric intermediates (brokers types) only add to the problem, since their ways of making money do not necessarily go in the direction of best overall efficiency (remember Enron). Misplaced subsidies also work against efficiency: a small business owner would get a better tax rebate from claiming a large SUV than a compact sedan for example. This is somewhat OT, so we should probably drop the issue for now.
121936. Marcus at 13:57 PM on 26 March 2010
        Is the science settled?
        Yes, I was going to make the same observation Phillipe. How much of the increase in efficiency is actually the result of Americans buying more European & Asian cars I wonder? We all know that US Auto makers fought tooth & nail against mandated efficiency standards-& where are they now?
121937. scaddenp at 13:57 PM on 26 March 2010
        What CO2 level would cause the Greenland ice sheet to collapse?
        If sealevel rise stayed at 320/c then I would agree. However at end of last glaciation, while there was a lot more glaciers to melt, the rate of temperature rise was much lower. We dont know how fast sealevel will rise with various scenarios but best guess is in 80-150cm by 2100. This puts you up around the 1000/c level. Not a problem for you or I but one for our descendents. You dont think mankind can control sealevel? We are raising temperatures so we just stop doing it. Or do think sealevel rise is due to some other unknown factor other than ice melt and ocean warming? I think we can control but I dont think we can impact GHG gases quickly which is why we start acting now for the sake of the future. And I think Florida problems are pretty trivial compared to Bangladesh and Nile. As to whether warm is good or bad - how many times do people have to tell you its all about rate of change not what you change to. And on weather stations - why dont you read the what people have pointed to you about "selecting" weather stations and the process by which station data is gathered instead of making inane comments?
121938. muoncounter at 13:53 PM on 26 March 2010
        CO2 was higher in the past
        Ned, "a much smaller increase in CO2 today will produce a climate that would have required much higher CO2 to achieve in the Paleozoic." That's an excellent way of putting it. The Ordovician's big dropoff in CO2 is usually explained by the massive, continent-wide carbonate banks (Trenton, Knox, Arbuckle, Delaware Basin, etc in the US) deposited in warm, restricted shallow seas. "These carbonate rocks constitute part of the “Great American Bank” (Ginsburg, 1982) that extended more than 3,000 km (1,864 mi) along nearly the entire length of what was the southern seaboard of the Laurentian continental mass" -- Pennsyvania Geological Survey The deposition of carbonates (Ca0+CO2->CaCO3, calcite) is linked to climatic change in this paper: "The accumulation of great volumes of carbonates during pre-Hirnantian late Ordovician, in regions where these deposits were previously absent, is suggested as a major sink of atmospheric CO2. This would have caused an important lowering of the average temperature". We don't see such massive carbonates deposited today.
121939. gallopingcamel at 13:15 PM on 26 March 2010
        What CO2 level would cause the Greenland ice sheet to collapse?
        muoncounter (#55), Sure there are negatives to a warmer climate but longer growing seasons in the higher latitudes is such a huge positive that it completely swamps the negatives. There is plenty of evidence for longer growing seasons in the Medieval Warm Period and the prosperity that resulted. What if temperatures go much higher than recent "Climate Optimums"? Then we have to look back to the Eocene and there is plenty of room for debate about conditions back then. It is very well documented that a cooler climate increases stresses on humanity through glacial advances, famines, pestilence, bad weather and much more. Asking for a cooler climate makes no sense at all given that we know what to expect.
121940. gallopingcamel at 13:01 PM on 26 March 2010
        What CO2 level would cause the Greenland ice sheet to collapse?
        I seem to be drawing a crowd here so I will try not to disappoint anybody. scaddenp (#53), with regard to the rate of sea level rise the current rate is quite low at ~320 mm/century. Since the end of the last Ice Age, sea levels have risen by ~120 meters, often at rates exceeding 10 mm/year. There were periods when sea levels rose very rapidly indeed as mentioned in earlier posts on this thread. According to the USGS, the melting of all the remaining ice sheets and glaciers would raise sea levels by another 80 meters. A serious matter for folks like me who live in Florida. The catch is how long will it take? You seem to believe the IPCC who predicted that the Himalayan glaciers would disappear by 2035. This nonsense has been dubbed "Glaciergate". You ask me what rate of rise I would like which seems to imply that you think mankind can control sea levels. I seriously doubt this but we can probably do a great deal of harm just by trying! There was an old lady who swallowed a fly.......
121941. Philippe Chantreau at 12:10 PM on 26 March 2010
        Is the science settled?
        Chris is back! Good to read you again! HR, your graph of auto mileage shows excellent progress for 20 years, then little to no progress until 2005. The average fuel consumed per vehicle is in fact on the increase since the early 90s. Nothing to brag about. Do you have any figures on how it has been in Europe?
121942. Ned at 12:05 PM on 26 March 2010
        Oceans are cooling
        Lyman et al. 2006 and Gouretski and Koltermann 2007 both illustrate that the oceans have been cooling since 2003. The same authors of Lyman et al. 2006 published a correction in 2007 noting that the apparent cooling had been an artifact of errors in the analytical method used. From their abstract: "Two systematic biases have been discovered in the ocean temperature data used by Lyman et al. [2006]. These biases are both substantially larger than sampling errors estimated in Lyman et al. [2006], and appear to be the cause of the rapid cooling reported in that work." Much has been published since then, including a followup by the same authors (Willis 2009)
121943. Ned at 11:48 AM on 26 March 2010
        Is CO2 a pollutant?
        suibhne writes: Is there no one with a background in thermodynamics that can give G&T a reasonable debate? Actually, a number of those coauthors have already explained the problems with G&T in various blog posts etc. elsewhere. But it will be nice to have something appear in a journal. If I were you I'd drop G&T and find some more productive ground for climate skepticism. This one is a lost cause.
121944. Ned at 11:39 AM on 26 March 2010
        CO2 was higher in the past
        Oh, yes, you're quite right .... I'm not at all minimizing the problems resulting from doubling CO2 on short timescales. Just pointing out that when people refer to the very high CO2 in the Paleozoic, 400 million years ago, they need to realize that it was countered by what was a much lower solar irradiance. If CO2 hadn't dropped over time, the world would be more or less uninhabitable today. Or, another way of putting it is that a much smaller increase in CO2 today will produce a climate that would have required much higher CO2 to achieve in the Paleozoic.
121945. michaelkourlas at 11:25 AM on 26 March 2010
        Oceans are cooling
        Lyman et al. 2006 and Gouretski and Koltermann 2007 both illustrate that the oceans have been cooling since 2003.
121946. suibhne at 11:16 AM on 26 March 2010
        Is CO2 a pollutant?
        I'm afraid that I have misled the readers of this thread. I thought that a peer reviewed article was about to be released. Instead it is a comment. Chris Ho-Stuart one of the authors addmitted None of my co-authors are prominent as physicists. The reference is: Joshua Halpern, Christopher M. Colose, Chris Ho-Stuart, Joel D. Shore, Arthur P. Smith, Jörg Zimmermann (2010) Comment On “Falsification of the Atmospheric CO2 Greenhouse Effects within the Frame of Physics”, (to appear in) International Journal of Modern Physics (B), Vol 24, Iss 10, March 30 2010. Is there no one with a background in thermodynamics that can give G&T a reasonable debate?
121947. chris at 10:18 AM on 26 March 2010
        Is the science settled?
        Geo Guy at 08:37 AM on 26 March, 2010 Your post is a little confused about water vapour as a greenhouse gas Geo Guy. Water vapour partitions into the atmosphere according to the atmospheric temperature (and pressure). It's effectively the atmospheric temperature that governs the levels of water vapour on average. With an Earth atmosphere warmed by the sun, and containing greenhouse gases that amplify the atmospheric temperature above the Earth's blackbody temperature, water vapour will partition according to the atmospheric temperature (Clausius-Clapeyron equation), further amplifying the atmospheric temperature (since water vapour is a greenhouse gas). With a constant CO2/methane/nitrous oxide etc. level and a constant solar output, the atmosphere will settle around an equilibrium temperature, a significant contribution to which will be the water vapour that partitions into the warmed atmosphere. Now: raise the CO2 levels. The atmosphere will warm. Since the atmosphere warms so the atmospheric water vapour levels increase. Sinc water vapour is a greenhouse gas the CO2-induced warming is amplified. To what then do we attribute the enhanced warming? Strictly speaking some is from raised CO2 and some is from the resulting raised water vapour which partitions at higher partial pressure due to enhanced CO2-induced warming. However, in essence all of the warming is a consequence of the raised CO2, even 'though part of this is the warming from the CO2-induced enhancement of water vapour concentration (the water vapour feedback). The water vapour feedback applies to anything that enhances (or reduces, of course) the atmospheric temperature. So if the sun became a bit brighter (say) such that the direct atmospheric warming is 1 oC, and the resulting water vapour feedback adds an additional x of additional warming, then the total warming from the solar enhancement + water vapour feedback is something like 1 + x + x^2 + x^3 + x^4 ... which is 1/(1-x). So if the water vapour response to a 1 oC warming is 0.5 oC then the total warming (when everything comes to equilibrium) is 1/(1-0.5) = 2 oC. Again, strictly speaking we could say that 1 oC of warming is due to the sun being brighter and 1 oC is due to the water vapour. But all the warming is essentialy due to the sun being brighter, since the water vapour feedback is a direct result of thesun-induced warming in this case (that's pretty much what is meant by "feedback"). This is all pretty well understood, and the water vapour feedback is (of course!) taken into account. No one "puts water vapor into a subordinate role"!
121948. scaddenp at 09:45 AM on 26 March 2010
        Is the science settled?
        Geo Guy - what causes water vapour increase - temperature rise. What causes temperature rise CO2. CO2 is the forcing - water is the feedback. Oh and so is albedo etc. It doesn't make sense to refer to feedbacks when looking for causes. Ditto, ice age cycle is driven by solar, not the CO2 feedback that amplifies it. On and on IPCC, PLEAZZE! The IPCC reviews and summaries the the published science. The talk about the "inaccuracies" is crock - so some human mistakes happen but is that the best you can do?? Note a lack of issue of WG1 which I bet has been heavily scrutinized. As for "radiative forcing" being coined by IPCC - where do you get these ideas? Do you understand it? Do you realise why it so useful? Want to google the published science that uses the term? You are at a website devoted to scientific answers to skeptic rubbish. Try looking at the articles.
121949. chris at 09:42 AM on 26 March 2010
        Is the science settled?
        re Geo Guy 08:37 AM on 26 March, 2010 Asserting falsehoods isn't helpful Geo Guy: Two here:

        Finally the term radiative forcing was coined by the IPCC - so it's best that we use a different term - after all their mandate was not to identify the cause of global warming but rather instead they set out to prove global warming is attributable to man's activity.

        (a) The IPCC was formed in 1988. The term "radiative forcing" has a long history in atmospheric science. Here's a paper from 1975, for example: D. W. Blake (1975) Radiative Forcing Of Annual And Semiannual Oscillations In Stratosphere Transactions-American Geophysical Union 56, 996-996. Therefore the term "radiative forcing" clearly couldn't have been "coined by the IPCC" could it, Geo Guy, since it was alread "coined" many years before the existence of the IPCC. (b) The IPCC wasn't set up "to prove global warming is attributable to man's activity." We can look at the IPCC mandate here: and see that your assertion is false.
121950. Marcus at 09:29 AM on 26 March 2010
        Is the science settled?
        Geo Guy, you're way off base for the following reasons: 1) Water vapor is about 100 times more concentrated in the atmosphere than carbon dioxide, yet contributes about 70% of the *natural* Greenhouse effect compared to the 20-30% contribution of carbon dioxide-this makes CO2 20 times more potent-on a parts per million basis-than water vapor. 2) Given this fact, even a 1% rise in water vapor is not sufficient enough to give the rise in temperature-especially given the short lived nature of water vapor in the atmosphere, as compared to CO2 & methane. 2a) CO2 levels have risen by 110ppm above pre-industrial levels-almost all of it in the last 40 years-which actually represents an almost 1% rise per year in atmospheric CO2 levels. 3) Water vapor is just as likely to act to increase albedo (clouds) as it is to capture outgoing long-wave radiation.