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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 87401 to 87450:

  1. Cosmic ray contribution to global warming negligible
    HR @ 27: The number of citations is an interesting metric. The AR4 cites Svensmark several times in their discussion about why the GCR hypothesis is not likely responsible for the observed climate change. Anyone refuting a paper should cite it. arch
  2. Cosmic ray contribution to global warming negligible
    Humanity Rules @25: Don’t quote me out of context. Why would you do such a thing? (Rhetorical question- just think about it). What I said was: “I admit that it is an interesting hypothesis, but only folks highly selectively biased by personal belief could possibly believe that galactic cosmic rays have a climate effect greater than that of the change we have seen in atmospheric CO2 levels. Little in the scientific literature supported it then and even less does now.” I never said there was little evidence to support the fact that CR may affect cloud cover. Indeed there is. What is lacking is substantial evidence that the changes in cloud cover are significant enough to affect climate to a degree greater than (anthropoid changes in) CO2 does. I thought this summary was a good one when it came out 2006 at the start of the CERN CLOUD experiments. I think it still is. HTH, arch
  3. CO2 is plant food? If only it were so simple
    I'm not quite sure whether I have correctly understood your post. Have there been experiments which include changes in CO2, temperature, water, competing plants (weeds) and pests? Another question: If the effects of higher CO2 are on balance negative, would a lower CO2 be better? Are there any experiments from which one can conclude what an optimal CO2 level would be for the world's major crops?
  4. CO2 is plant food? If only it were so simple
    Excellent post! I would nit-pick at you choice of words in the paragraph: "Only recently have researchers begun to pull away from these controlled settings and turn their attention to outdoor experiments." I would say that the experiments aren't recent; rather, they were started some time ago but it takes several years before the results can be reported, and the results are recent. Back to the main idea, I've often replied to "CO2 is plant food" by saying "yes, where CO2 is a limiting nutrient" and these same people usually have irrigated and fertilized lawns and gardens but never thought of trying to add CO2. I also like to point out the tree-topped mountains where I live, and ask why do the trees grow up there and not on desert and chaparral? For the thinner air? Reading your post, I'm beginning to think my "where CO2 is limiting" response is too simple. Rising CO2 affects plant growth whether it is or isn't a limiting nutrient. thanks, jg
  5. Cosmic ray contribution to global warming negligible
    Going off-topic for a moment. Seems like we have bigger things to worry about than the 'ideologically motivated' demise of GCR/climate research. the House of Representatives proposed budget includes no replacement for the NOAA polar orbiting weather satellites.
  6. Cosmic ray contribution to global warming negligible
    "Those that seem to want to kill the CGR/climate connection are as ideologically motivated as the worst sceptics" Yeah, that's why we insist that the GCR/climate connection violates the 2nd law of thermodynamics, just like certain skeptics insist that radiative transfer theory does. /snark
  7. CO2 is plant food? If only it were so simple
    This is a good article. I would come at it from a different angle. Greenhouse studies are not a good indication of a real world scenario; most people agree on this. FACE studies are a bit better, and show less improvement from CO2 enhancements than greenhouse studies. But if you want a more accurate reflection (although still not perfect) of how CO2 increases will affect crop plants in the real world, you have to account for the shifting climate zones. For instance, you try growing crop varieties commonly used in Missouri, but try to grow them in central Texas, adding all the CO2 you want. Anyone want to bet on whether the results will continue the downward trend on yield improvements seen in moving from greenhouse to FACE?
  8. Lindzen Illusion #1: We Should Have Seen More Warming
    KL #94: top of the atmosphere energy imbalance is not the same as radiative forcing at the surface.
  9. CO2 is plant food? If only it were so simple
    The article states "FACE studies...; unfortunately, the results of these studies are not nearly as promising as those of greenhouse studies, with final yield values averaging around 50% less in the free-air studies compared to greenhouse studies " In looking at the reference cited, it's clear that the article should state that the "with the INCREASE in final yield values averaging around 50% less in ..... " As the first reference ( Leaky et al. 2009 provided in that section of the article says, there are 6 important lessons learned from FACE studies: "First, elevated CO2 stimulates photosynthetic carbon gain and net primary production over the long term despite down-regulation of Rubisco activity. Second, elevated CO2 improves nitrogen use efficiency and, third, decreases water use at both the leaf and canopy scale." ..... (read the article to see the rest) So CO2 is not only a plant food, but it also decreases water use and improve the efficiency of nitrogen use.
  10. Philippe Chantreau at 01:36 AM on 28 April 2011
    Cosmic ray contribution to global warming negligible
    HR: "Applied science is never based on one piece of evidence and an idea is never dismissed because one piece of the puzzle still eludes us." Curiously, that is exactly what some regular skeptic contributors have suggested when they protested against the larger picture type of concept. I will make sure to cite you when running into attempts to do exactly that by so-called climate skeptics. I know it won't be long until it happens. In this case, it can be reasonably argued that the physical mechanism is more than just "one piece of the puzzle." "that's funny." Why? "The necessary experiments" is exactly what CERN's CLOUD program is all about. You know, that darn government-run, public-money scientific research thing. So far the only truly clear result is that the chamber walls overwhelm whatever other effect could possibly exist. Now, whomever is running the program must manage to get money to continue it. It may be decided that CERN's priorities are elsewhere and I wouldn't venture to emit a judgement on the issue if it happens. I'm sure there are countless people better qualified than me to say how CERN should allocate resources. However, your snark is unwarranted. I'm all for understanding nature, even that part.
  11. Lindzen Illusion #1: We Should Have Seen More Warming
    Ken Lambert at 95 says This should not be a cause of the abuse and denegration of any scientist as long as the opinions held are honest and in good faith. Error is not a crime. ----------- I agree. But: Lindzen has written one newspaper article, if memory serves,.that abuses and denigrates other scientists, so maybe you should explain this to Lindzen. Lindzen is often presented as an authority, which means he should check his facts and not dogmatically communicate the same wrong information over and over again. Science is a collective enterprise, so the tendency to claim yourself as correct and everyone else as wrong, incompetent or dishonest is not a valid position. If Lindzen is propagating information which is in error, people should be able to explain why without having their own motives impugned.
  12. CO2 is plant food? If only it were so simple
    Pete @10 raises a very interesting point. It could be that elevated CO2 creates more biomass to burn in a warmer world.
  13. Lindzen Illusion #1: We Should Have Seen More Warming
    Re "Lintzen is plumbing for the low end, others the high end." @94, I do agree that Lindzen is aiming for the low end alright (< 1 K), in the very tails of the probability distribution function for climate sensitivity in fact. Lindzen is an outlier in more than one sense-- we are still waiting for his mystical negative cloud feedback mechanism to kick in, while evidence to the contrary continues to mount. Not sure who the "others" are in the above quote, but the IPCC is actually stating the middle ground for climate sensitivity at 3 K, and that is derived using data from multiple independent lines of evidence and studies (e.g., Knutti and Hegerl 2008). To be high they would have to be calling for a climate sensitivity greater than about 4.5 K (see Annan and Hargreaves 2006, for example), and a paper by them in 2009 came to a similar conclusion supporting a most likely climate sensitivity near +3 K. See also Knutti et al. (2006). SkS continues to be an excellent source for genuine scientific information and a beacon of light in a "debate" often filled with invective, vitriol and hyperbole. Unfortunate then that contrarian posters have taken it upon themselves to try and ruin has become a valuable pedagogical tool.
  14. CO2 effect is saturated
    Berényi - The only difference between those two phrases is in which you would use in polite company. Both indicate data made up, manufactured, in order to prop up an argument. Given that Trenberth 2009 is described as an update to Kiehl and Trenberth 1997 (see Trenberth 2009, second paragraph, for the reference), that is the very first location to look for items not discussed in detail in Trenberth 2009. I therefore consider your language here unwarranted. "Somewhat ad hoc" is a reasonable description given the 1997 paper. However, this does not address the underlying issue of using a summary, one that has been adjusted for internal consistency, in place of a GCM. From the 1997 paper, page 10: "The values put forward in Fig. 7 are reasonable but clearly not exact. The purpose of this paper is not so much to present definitive values, but to discuss how they were obtained and give some sense of the uncertainties and issues in determining the numbers. Several quantities in Fig. 7 are not adequately measured to pin them down as much as desirable, and the global climate models are not yet good enough to justify refining the estimates here, which are based on a much simpler but appropriately tuned and observationally constrained radiation model. By putting all the estimates together, however, the fact that the total heat budget at both the surface and the top of the atmosphere has to balance and all the components add up is a considerable constraint and lends some confidence to the values assigned. Regardless of the errors assigned to each component, the fact that the components sum to zero means some errors must cancel." (emphasis added) The 2009 paper has improved data, fewer uncertainties, but this is still a constrained summary and overview, not in itself a GCM. The biggest, most powerful constraint is that everything has to add up, and that "...some errors must cancel". Now back to the subject matter of this thread. There are definitely uncertainties in cloud absorption, much smaller uncertainties in water vapor distribution. But there is no uncertainty in the fact that CO2 is not saturated at current concentrations.
  15. Lindzen Illusion #1: We Should Have Seen More Warming
    "The IPCC 95% confidence range puts the total net anthropogenic forcing at 0.6 to 2.4 W/m2 (Figure 1)." and "For example, Hansen et al. have a new draft paper out which puts the aerosol forcing at -1.6 W/m2. CO2 levels have continued to rise since the IPCC report, and the CO2 forcing is now 1.77m W/m2. If we incorporate these figures, the most likely net forcing value becomes 1.5 W/m2" But of course Dr Trenberth says that the net forcing is actually 0.9W/sq.m NOT 1.5W/sq.m when the 'CLIMATE REPONSES' are taken into account. Surely this is enough of an indicator of the wide range of potential NET forcing to make a similarly wide range of temperature rise outcomes. Lintzen is plumbing for the low end, others the high end. This should not be a cause of the abuse and denegration of any scientist as long as the opinions held are honest and in good faith. Error is not a crime. The tone and quality of debate on this site has deteriorated since Moderators were appointed { - snip -}
    Moderator Response: [muoncounter] Complaints about moderation snipped. You know the rules; when you don't follow them, you have no one but yourself to blame.
  16. Waste heat vs greenhouse warming
    RSVP - The difference in TOA effects between AHF (more coming in) and greenhouse gases (less energy going out) is very clear. Think of a pot on a stove. Adding AHF is equivalent to turning up the burner. The stew gets hotter, more steam comes out, it recovers equilibrium (stops changing temperature) when in = out. GHG's are equivalent to putting a lid on the pot, reducing outgoing energy. Less steam comes out, the stew gets hotter, it recovers equilibrium when in = out. Even leaving aside the small matter (!!!) of two orders of magnitude difference in energy as you wish to, the decreased TOA IR demonstrates that the primary cause of global warming is a reduction in energy loss to space, not an increase in energy fed into the climate. AHF therefore cannot be the primary cause of global warming. Your fixation on this in the face of logic, numbers, and physics is most unfortunate.
  17. CO2 is plant food? If only it were so simple
    HR @6 I still don't get why 'CO2 is plant food' is not a good general point to make Two reasons: 1. the implication of your statement is that from this it automatically follows that the agricultural yield of the planet will increase with higher levels of CO2. As Pete Dunkelberg points out @10, there are missing, more questionable steps in that argument 2. Your statement can have the implied follow-on "so therefore is nothing dangerous about CO2" which, as I'm sure you're aware, has all kind of logical fallacies attached to it. Changes to commodity prices over recent history don't suggest any beneficial effect on crop yields yet! (I accept, obviously, that this is somewhat crude measure)
  18. Pete Dunkelberg at 22:22 PM on 27 April 2011
    CO2 is plant food? If only it were so simple
    Try a full accounting of plants vs CO2 at 550 ppm. With tundra and rain forest converting to more CO2 and even temperate plants succumbing to wildfire, and crops in broad continental interiors failing due to heat waves, it looks like CO2 turning existing plants into more CO2 rather than vice versa ;) At any temperature, what humans need is not "plant food" but "people food". All us animals need protein, which requires nitrogen. Plants can not turn carbon into nitrogen. Legumes with their nitrogen fixing bacteria may be able to produce more protein given more CO2 and genetic engineering may help other crops to use nitrogen for protein more efficiently but first these plants have to beat the heat. Good luck on that.
  19. CO2 is plant food? If only it were so simple
    I am delighted to see this topic receive more nuanced attention as it is generally neglected. We are indeed engaged in a vast experiment that has veered out of control, whereas even the best scientists barely understand all the complex ramifications to plantlife. I would venture to say that we are well behind the curve even compared to the relatively recent revelations about ocean acidification, as far as comprehending the cascading effects in the terrestrial ecosystem by altering the composition of the atmosphere. The consequences of dying trees - losing an essential CO2 sink and the production of oxygen, not to mention habitat for countless species - are at least as dire as losing coral reefs, pteropods and phytoplankton. It has so far been impossible to remove existing ambient background levels of tropospheric ozone for controlled experiments on trees and because of this, the long-term impacts are generally ignored. It's kind of like sea level rise - everyone knows it's going to be far higher than IPCC predictions based solely on thermal expansion, but because there is too much uncertainty in modeling the rates of melting ice sheets, it is simply left out of the predictions. Fine - that's science. The same is true for trees. Anyone the least familiar with ozone knows it is toxic to vegetation, and knows the background levels are inexorably rising. But because no one has been interested or, perhaps, had the funding to do a gigantic, enclosed, decades-long experiment comparing trees growing with pre-industrial levels (basically zero) to today's (anywhere from 40 ppb to 80 or more) we act as though there is nothing significant to worry about. And yet in the real world, in this uncontrolled experiment, it is easy to ascertain that trees everywhere are dying, and at a rapidly accelerating rate. This is true for trees of all species, in all habitats - even young trees being watered in nurseries. Their decline is chalked up to all sorts of other opportunistic causes - insects, disease, fungus, drought, road salt, natural gas line leaks, climate change and on and on. But there is an immense, global pattern here which is attributable to the one thing that trees everywhere share in common - the atmosphere, which is poisonous, and to which they are exposed season after season. They have the tree equivalent of AIDS, a compromised immune system. It has been my hope for years that someone with scientific credentials will reveal this existential threat before we lose the ability to preserve seeds and nuts. This article is a great leap forward, with a number of excellent references - there are many more links to published research collected at the top of my blog, http://witsendnj.blogspot.com/
  20. CO2 is plant food? If only it were so simple
    #6 HR. In a sense, H2S is the "closest" relative to H2O, and it can surely be useful. Why, then, don't we praise its presence as a source of sulfur, which is biochemically essential? When we talk generally about different substances, we do of course refer to their effects in general. This post is a general, balanced account of CO2, or you should at least acknowledge that it is a good and honest try at that.
  21. Berényi Péter at 20:52 PM on 27 April 2011
    CO2 effect is saturated
    #146 KR at 08:28 AM on 27 April, 2011 You should, then, be aware that in English "pulled out of thin air" has extremely negative connotations with regard to numbers, namely "manufactured, made up, baseless". English is obviously not my native language, and I am happy to learn. But it was always my impression there was a difference between numbers pulled out of thin air or pulled out of the ass. Anyway, I certainly meant atmospheric IR window radiation flux in Trenberth 2009 is baseless, it is produced seemingly out of nowhere, as if by magic. And Kiehl & Trenberth 1997 does not make it any better. They themselves admit "The estimate of the amount leaving via the atmospheric window is somewhat ad hoc". And indeed it is, by the method they say they've arrived at it. So let's settle at a qualification like it was somewhat ad hoc. Is that OK? I do not believe in a value "that has been known for >80 years", but never measured. Global average IR radiation flux escaping directly from surface to space is an important quantity. If it is not known, average atmospheric IR optical depth can't be calculated and talking about trends in an unknown quantity is just futile. I do not believe either atmospheric transmission can be properly determined as a side product of the line-by-line radiation models. The HITRAN Database is a magnificent product, but with no established cloud (and water vapor distribution and surface emissivity) model it is useless for this purpose. Also, atmospheric transmission is heavily influenced by the gazillion weak absorption lines still missing from the database (because of measurement issues), their far wing shapes and the ill-understood water vapor continuum.
  22. Cosmic ray contribution to global warming negligible
    #33 HR. I suggest you contemplate the difference between "killing the connection" and quantifying it. I think this is quite analogous to what I often experience in medicine/health studies, where we may identify covariates in regression models that may be highly significant statistically, because we have so many subjects and good precision. BUT only account for, say 0.5% or less of the total variation - significant but, in the majority of cases, not relevant. If all the self-declared "skeptics" could make it a routine exercise to estimate the likely net effect of what they are looking at, and from there do a quick judgment of relevance, the discussion would benefit a lot. And, of course, one must take all the available data into consideration when estimating. By all indications, the eventual climate effect of GCR is very small, and if it were very strong, this would normally have been demonstrated or strongly hinted at by now.
  23. Antarctica is gaining ice
    We were also talking about LAND ice in Antarctica... not sea ice. Or, at least, that's the only thing I can think of which '10 year trend' might have been referring to. Since surface temperatures on most of the continent (peninsula excepted) seldom get above zero, land ice wasn't expected to start declining for decades. Yet it already has because rising ocean temperatures have cleared out sea ice and ice shelves while also undermining coastal land ice... all of which leads to faster ice export and the recently observed continent wide trend of declining ice.
  24. CO2 is plant food? If only it were so simple
    For the very simple reason, HR, that your side of the debate use this over-simplification to con people into thinking that it'll be perfectly fine to keep artificially altering the composition of our atmosphere. A 30% increase in crop seed yields might sound great, but are those yields pre-or-post acclimation? What will happen to those yields in warmer conditions, where we are now learning that levels of Rubisco Activase are lower? How will these yields be impacted by changes in insect pests, soil-borne diseases & weeds-all known to be altered by changes in CO2 alone-even before we consider the impacts of eCO2 on mean temperature & hydrology? What happens to Protein, Zinc & Iron levels in those rice plants grown under eCO2 conditions? You can't just avoid these many issues in order to paint a Utopian vision of an eCO2 world-yet that's exactly what you & your fellow contrarians do quite regularly. Ultimately, though, its because the statement that "CO2 is a plant food" ignores the fact that water, nitrogen & trace elements have a far more limiting effect on plant growth-in the mid to long term-than CO2 does.
  25. HumanityRules at 19:02 PM on 27 April 2011
    CO2 is plant food? If only it were so simple
    I still don't get why 'CO2 is plant food' is not a good general point to make. All science (in fact all aspect of human experience) has ever increasing levels of complexity but it doesn't mean that you can't also make generalized statements about subjects. Take for example this review which makes many of the same points as made here but which still doesn't shy away from stating "The stimulations of crop seed yields by the projected CO2 levels across FACE studies are about 18% on average and up to 30% for the hybrid rice varieties and vary among crops, cultivars, nitrogen levels and soil moisture." in it's abstract.
  26. Waste heat vs greenhouse warming
    KR 386 "In fact, if waste heat was the cause of warming, we would see an increase in outward IR due to the planet being over equilibrium temperature, rather than the observed decrease as the climate catches up to the GHG forcing. " Another contradiction: Here you say there is now less outward IR being observed, when you have been saying that waste heat is "no different from any other radiative forcing", and that as temperatures go up, IR increases. Based on your "logic", the Earth must now be cooling.
    Moderator Response: [DB] It all has to so with the definition of a "forcing". That is where you are having a disconnect.
  27. CO2 is plant food? If only it were so simple
    Thanks for this. Though I think it is written well enough for intermediate readers to understand as well as advanced. I hadn't seen the temperature angle tackled like this before - very interesting. Further to the interation with other species section it has been shown that lacwing predators of aphid pests become less efficient consumers under elevated CO2 (Gao et al.; 2010*). Which, if combined with increased fitness of pests & pathogens as hypothesised by Gregory et al. (2010)** signls a possible need for increased pesticide load under elevated CO2. Is Sherwood Idso any relation to the CO2"science" Idsos? Speaking of them, I wonder how many of the studies cited above are also cited over there. *Elevated CO2 lessens predation of Chrysopa sinica on Aphis gossypii. Entomologia Experimentalis et Applicata. 135 **Integrating pests and pathogens into the climate change/food security debate. Journal of Experimental Botany. 60
  28. Waste heat vs greenhouse warming
    KR 398 "Which is 2 orders of magnitude larger. " Interesting to know if you theoretically allow any amount of waste heat to cause a global warming effect. From what you have repeated many times, as the amount of waste heat energy dumped into the environment increases, temperature goes up, and all this just makes for more outward radiation, and therefore there is no concern for global warming on the account of waste heat. On the otherhand, in post 398 (and possibly other places), the "two order of magnitude" energy difference does seems to matter. Is it possible to mend this contradiction?
  29. Christy Crock #4: Do the observations match the models?
    Dear Berenyi Peter, You say @35 that "... it is not a quote..." and then, still @35, "... it is a quote indeed." I'll take that to mean you assert that what you wrote was a quote and was not a quote. That assertion is a plainly a contradiction and obviously false. But @25 you asserted also 'from a false proposition anything follows ... along with "I am the Pope" '. I am sure Bertrand Russell would enjoy your nod to him, and readily agree that, within your manifest system of reason, you have (somewhat elliptically) demonstrated to us all that you are, indeed, the Pope. That may be why some of the natural skeptics on this site, who actually doubt that you are, in fact, the Pope, are thinking instead that there is probably a flaw in your reasoning or assumptions. But why limit your career to Pope? "Haiku on the universal euhemerism of Bertrand Russell. If we knew that one equals two, then I'd be a God and so would you." Best regards, Don
  30. Wakening the Kraken
    Daniel, I think this article needs a major update per the recent Shakhova slide presentation linked over at CP. See my comments just after yours there.
  31. CO2 is plant food? If only it were so simple
    Yes, excellent summary Dawei.
  32. Christy Crock #4: Do the observations match the models?
    Hey anyone, and maybe Dikran Marsupial in particular. (BP and Gilles, you can skip this.) I am confused by how "variability in model prediction" is being analyzed in this thread in order to characterize ensembles of climate models. From my point of view, one certainly expects to get variability in the behavior of a particular dynamical system if one changes initial conditions or the values of time-varying parameters. One also gets variability of outcome if one builds stochastic uncertainty into the dynamics but keeps initial conditions fixed and doesn't alter the time dependence of parameters. (And clearly different models can produce different outcomes.) There are several reasons why the same model can produce different outputs on different runs. My question concerns the source of variability within the individual models discussed in this thread. Is it due to uncertainty in initial conditions, uncertainty in time-dependence of parameters, an assumption that the dynamics are stochastic, numerical instability or chaos in the model, or some combination of these sources of variability? Anyway, I believe "ensemble mean" is a wonderful, ancient, and useful concept, it is just that for climate models I don't have the background to identify the sources of run ensemble variability either within or between models. (This is just a question about the mainstream models, not about the actual climate variability as it unfolds before us.)
  33. CO2 is plant food? If only it were so simple
    I knew nothing about the C3 and C4 pathways until recently when I was trying to understand why the C13/C12 isotope ratios for fossil carbon where different than for atmospheric carbon (thus allowing the identification of fossil carbon on the atmosphere). The reason is that while C12 and C13 are chemically identical, but their different masses mean that they diffuse across membranes at different rates. Different diffusion steps mean that the two pathways fix different amounts of C13. The C4 pathway is more efficient, but only evolved recently.
  34. CO2 is plant food? If only it were so simple
    This post is a balanced and understandable treatment of a very complex topic. Well done!
  35. Models are unreliable
    342. All that happened after we mucked it up. Look, we are in uncharted territory. I know perfectly well that the millions of tons of CO2 we have dumped are producing some warming. Did you read 339? What I am saying is that hindcasting may be misleading. You may recall that I am haunted by a feeling that we are missing a piece to the puzzle, whether it be before our noses and we are overlooking it, or something beyond our current understanding. I fully realize that I, who have repeatedely invoked Occam, am ignoring him here. But nothing we have comes close to explaining the three things in 339.
  36. CO2 is plant food? If only it were so simple
    And just to make things more complicated it is being reported that CO2 fertilization is killing koalas because CO2 fertilized plants put more of their energy into structure. Eucalyptus leaves become harder for present day koalas to digest because they are more fibrous. This is probably not restricted to eucalyptus and might indeed affect some of the plants we eat, or at least affect more animals than just the Koala.
  37. Clouds provide negative feedback
    Sphaerica (RE: 152), "It matters what types of clouds form, where they form, and when they form. More clouds in northern latitudes in winter will not nave a net cooling effect. High clouds made of ice crystals that are transparent to visible light will not have a net cooling effect. Clouds that build beyond a certain critical depth will not have a net cooling effect. OK, explain specifically how all the various cloud types will respond in a way that results in a net warming effect on the next few watts at the surface and specifically why all different cloud types don't respond this way to the original 239 W/m^2 incident on the surface from the Sun. "It's more complicated than your simplistic logic makes it sound." I know the balance is complicated. It doesn't change the fundamentals. Besides, Dessler doesn't get into different types of clouds in his analysis.
  38. Models are unreliable
    No truckmonkey, we know that isnt true. The isotope ratios for fossil fuel produced CO2 is different from that produced by carbon cycle feedbacks. If you look at the isotopes in CO2 from ice core bubbles, the increased CO2 during warming is from carbon cycle. If you look at isotope ratio in current atmosphere, you see increase is due to fossil fuel. At the moment, the carbon sinks are cleaning up about half our emissions. Over longer time, this will reverse.
  39. Clouds provide negative feedback
    Sphaerica (RE: 15), "your logic that if the effect of clouds is a net negative in the current climate, then a changed climate must have more clouds with the same net negative effect, only more so, is simplistic." No, not really. My point is there is really no physical or logical reason why the net cloud feedback would suddenly switch from negative (cooling) to positive (warming) on the next few watts incident on the surface, especially to cause a net warming effect so much greater than the response of the system to the original 98+% (239 W/m^2) incident on the surface from the Sun.
  40. Clouds provide negative feedback
    muoncounter (RE: 151), "Oh, that makes it all perfectly clear. A mechanism of warming, 'not in dispute,' doesn't conflict with net negative feedback? Do you have any evidence to support this astounding statement?" I'm not sure I understand your objection. The net effect of clouds, globally averaged (night and day combined), is to cool. The fact that clouds are much better at trapping outgoing surface emitted radiation than the clear sky, which makes their net effect at night to retain more energy than the clear sky, would only be significant it was more than the energy the clouds reflected away during the day.
  41. Cosmic ray contribution to global warming negligible
    Yes Muon, funny how the "skeptics" play up the so-called "uncertainty" surrounding Anthropogenic Warming, yet are very quick to promote any other potential source of warming-regardless of how *weak* the foundation for it is. Anyone would think they were trying to "kill the CO2/climate connection".
  42. Clouds provide negative feedback
    150, RW1, What else does Dessler say in his paper? Let me give you a hint... your logic that if the effect of clouds is a net negative in the current climate, then a changed climate must have more clouds with the same net negative effect, only more so, is simplistic. It matters what types of clouds form, where they form, and when they form. More clouds in northern latitudes in winter will not nave a net cooling effect. High clouds made of ice crystals that are transparent to visible light will not have a net cooling effect. Clouds that build beyond a certain critical depth will not have a net cooling effect. It's more complicated than your simplistic logic makes it sound.
  43. Models are unreliable
    Sorry about the double post. Don't know how to retract it. All I did was refresh. 340. I am saying that until we mucked it up the rise in temperature produced the rise in CO2.
    Moderator Response: [DB] Refreshing after posting will result in a double (triple, quadruple, etc) posting. You are not the first, nor will you be the last.
  44. Clouds provide negative feedback
    RW1#149: "net effect of clouds at night is to warm (or slow heat loss)... Again, this is not in dispute, nor does it conflict with net negative feedback for clouds." Oh, that makes it all perfectly clear. A mechanism of warming, 'not in dispute,' doesn't conflict with net negative feedback? Do you have any evidence to support this astounding statement? Or does your model simply require that you assume a net negative feedback and thus do not need to bother with any evidence?
  45. Clouds provide negative feedback
    Sphaerica (RE: 148), "You keep saying there's a net negative cloud effect, but (1) you don't prove it," I've provided much evidence and logic for net negative cloud feedback. Even Dessler says in his paper the net effect of clouds is to cool by 20 W/m^2. "(2) as several people have pointed out, the important factor isn't the net current effect, it's the net change as a result of warming." I'm aware of this, but I'm not the one making the claim that the net effect of clouds is suddenly going to switch from cooling to warming on the next few watts incident on the surface.
  46. Cosmic ray contribution to global warming negligible
    HR#33: "This obscure paper " Comments on the Rao paper are here on the prior Its cosmic rays thread. Not so obscure. "Those that seem to want to kill the CGR/climate connection are as ideologically motivated as the worst sceptics" Wow, how did you get there? Who is trying to kill the connection - if so, why did CLOUD even get built? What are the 462 citations you claimed in #27? How does that in any way suggest anyone is trying to kill the connection? Please do not make such accusations without any trace of substantiation. No, the problem with the GCR/climate connection is that no one can substantiate it and that 'skeptics' are desperately trying to cling to it. Do you think they are ideologically motivated?
  47. HumanityRules at 12:45 PM on 27 April 2011
    Cosmic ray contribution to global warming negligible
    28 Philippe Chantreau As far as I'm aware the necessary experiments have yet to be performed to answer your criticisms although there is plenty of speculation on mechanisms and even some supporting evidence (such as much of Harrison's work). Applied science is never based on one piece of evidence and an idea is never dismissed because one piece of the puzzle still eludes us. I guess you fully support the continued investigation of this problem? "I'm not so sure that 462 citations in 14 years is that remarkable." That's funny! 29 muoncounter This obscure paper from the Indian Academy of Science Journal seems to suggest the impact on global temperature is very different to the paper Ari has presented. Very few scientists have bothered to quantify the impact of CGR on global temperatures, I'm not sure that Svensmark has even bothered to do this. I think my position on this science is much like the rest of climate science. Uncertainty in the science rules, which suggests further investigation before firm conclusions can be made. Those that seem to want to kill the CGR/climate connection are as ideologically motivated as the worst sceptics. And the IPCC position on this issue can only have the effect of strangling research on this subject.
  48. Clouds provide negative feedback
    muoncounter (RE: 47), "I don't know where you live, but in my neck of the woods, nights don't get cool when there's high humidity (which is almost always) or high clouds. But here's how an actual weatherperson puts it: Clouds are regions of a high density of saturated air, (which form cloud droplets). Clouds (especially low thick clouds) have a high ability to absorb and re-emit longwave radiation. Thus, on cloudy nights much less longwave radiation is able to escape to space. Holding in heat at night is a fingerprint of the enhanced greenhouse effect. So your thesis that clouds will always be negative feedbacks doesn't hold water." Yes, net effect of clouds at night is to warm (or slow heat loss). This is because clouds are better at 'trapping' outgoing surface energy than the clear sky is. Again, this is not in dispute, nor does it conflict with net negative feedback for clouds. Globally averaged data automatically includes the effects of night and day.
  49. Antarctica is gaining ice
    RyanS#78: "seasonally the ice expanse at the poles swings wildy. In winter ocean ice is a multiple 5-10 times what it is in summer, ... there is and always has been very much melting at the poles" If by 'poles,' you're including the Arctic, then you are: a). off topic b). making an unsubstantiated claim c). incorrect. Arctic ice extent did not always swing wildly; there are a number of Arctic ice threads with plenty of actual data to examine. If it's credibility you seek, point to some numbers.
  50. Antarctica is gaining ice
    CBD I'm not exactly sure what you're getting at in the first paragraph. Are you eluding to the fact that ice melts or doesn't melt and for all temperatures below 0 the ice will be frozen? That's true but we're not dealing with a smooth climate, seasonally the ice expanse at the poles swings wildy. In winter ocean ice is a multiple 5-10 times what it is in summer, as a ball park range. So there is and always has been very much melting at the poles and our concern is the mean figures over time.

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