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Comments 75951 to 76000:

  1. Dikran Marsupial at 01:59 AM on 3 September 2011
    Mythic Reasoning about Climate Uncertainty
    Jonathon I see little reason* to depart from the forcings and uncertainties given by the IPCC: BTW, ENSO is not a forcing, it is an element of internal variability and if by "urbanisation" you mean the urban heat island effect, then urban areas are such a small proportion of the Earths surface that their effect on actual (rather than as estimated by raw area-weighted averages of surface station data) global surface temperatures is essentially insignificant. * There are other forcings not mentioned in the table, e.g. the GCR theory, however the current level of scientific undersdtanding (LOSU) and observational evidence do not suggest that they will substantially alter the overall picture.
  2. Trenberth on Tracking Earth’s energy: A key to climate variability and change
    Wow. As I read #193 I found myself wondering what part Pyramid Power and Hagbard Celine had to play in this hypothesis. Doug, you are attempting to overturn 100+ years of science without showing a single equation or data point. That might get you a special on the (now ruined) History Channel following Ancient Aliens but the scientific community is not going to take you seriously.
  3. GHG emission mitigation solutions - a challenge for the Right?
    KR, that makes sense. What I was thinking of was the processed silicon that companies like Solyndra needed to buy. But now it looks like I could soon be wrong: http://www.solarpoweradelaide.net/the-end-of-the-silicon-shortage.html and that would be a very good thing.
  4. Trenberth on Tracking Earth’s energy: A key to climate variability and change
    Cotton: "In effect, the empirical data debunks the concept that climate is forced by factors involving solar insolation and atmospheric gases." Long-term orbital cycles, then, should have very little effect on temps, and certainly not the effects shown in the established long-term temperature record. Low-latitude glacial deposits should be impossible, despite the historical evidence. And stratospheric cooling with tropospheric heating -- well, it must just be a long-term cycle with some other explanation. Locked in, this one.
  5. Mythic Reasoning about Climate Uncertainty
    I am curious as to what everyone would say is the contribution to the industrial-era warming and uncertainties from the following forcings: CO2, urbanization, solar, ENSO, volcanic activity, and albedo (feel free to add others as deemed appropriate).
  6. Lessons from Past Climate Predictions: IPCC SAR
    Correct Dave. Model inputs are things like changes in GHGs and solar irradiance, and the physics of how much of a radiative forcing these cause. The resulting temperature change, and thus the climate sensitivity, are outputs of the model. Or I guess more accurately, the sensitivity is built into the model, and can be determined by seeing how much the temperature changes in response to a given forcing. That's my understanding anyway - I'm no climate modeler.
  7. Trenberth on Tracking Earth’s energy: A key to climate variability and change
    DougC#193: "There is further empirical support ... empirical data debunks the concept that climate is forced by factors involving solar insolation" Your conclusions based on this very limited empirical exercise were shown to be completely incorrect the last time around on this very thread. On further inspection of #193, your earth-heat-lunar-tides idea is utterly unsubstantiated as well (and in my opinion, patently absurd). The challenge made there still stands: show data and research from credible sources - peer reviewed whenever possible - that support your 'diffusion will prevail' model. Until you can meet that challenge, your ideas remain merely your personal opinion. Until you can meet that challenge, all of your pronouncements must be read with the preface, 'in my opinion.'
  8. Mythic Reasoning about Climate Uncertainty
    scaddenp#63: "Uncertainty cuts both ways." Would that it did, but 'skeptics' have absolute belief in their myths. They know that natural cycles, for example, are more important than greenhouse gases could ever be. How they know this is of course unclear, but it doesn't seem to matter. The skeptical 'its a natural cycle' must therefore be met with a resounding 'how do you know that?' and 'what is your uncertainty?' If there could be a rational answer to those questions, then we could have a slightly more level playing field.
  9. Venus doesn't have a runaway greenhouse effect
    Again, a Climastrology button is needed for Rosco. These sorts of creative science perception discussions need a thread of their own, because they really don't belong anywhere, and hence tend to wander about willy-nilly. Rosco barely met the requirements of this thread by rather randomly throwing the word "Venus" into his post. This sort of Alice-through-the-looking-glass discussion has been happening just far too often in recent months.
  10. Trenberth on Tracking Earth’s energy: A key to climate variability and change
    Again, a Climastrology button is needed for Mr. Cotton.
  11. GHG emission mitigation solutions - a challenge for the Right?
    Eric (skeptic) - "Silicon for solar does not have economies of scale as far as I can see. What does have economies of scale is large FF and nuclear power plants (perhaps unfortunate but it is a fact)." From what I understand, Eric, the economy of scale for solar power (PV at least) is in the production of the solar panels. A number of commentaries on the recent Solyndra bankruptcy (here, for example) noted that they just couldn't reach the production numbers required for their panel prices to be competitive. I can't find the reference right now, but they had recently dropped production levels, and saw their panel prices double to ~$3.80/watt - when $2.00/watt was their break-even price. Low production numbers for solar panels just aren't economically viable. Meanwhile, Chinese panels (slightly less efficient than Solyndra, but...) were coming in at a price of $1.20/watt. Solyndra just got out-priced.
  12. Venus doesn't have a runaway greenhouse effect
    Rosco, did you read the paper I linked to? Did you? I recall you saying, "I'm more than open to listen." Reading is "listening" when writing is the primary means of communication. You are not arguing from a physical model. You're arguing from what seems to be right to you. If you accept "seems to be right" as an argument, then we are at an impasse, because then my word becomes as good as yours, and we're all right. If you don't accept "seems to be right" as an argument, then start describing your physical model. Everything you've said so far suggests that you don't believe that CO2 absorbs and emits at specific frequencies (broadened by pressure). That might be a good place to start understanding. What are the emission/absorption spectra of Earth's (or Venus') ten most populous atmospheric gases? If you don't know, then you're not prepared to enter the discussion. While some here might tell you to go away (either directly or in tone), I won't.
    Response:

    [DB] "While some here might tell you to go away (either directly or in tone), I won't."

    I think you speak for everyone in that our sincerest wish is for Rosco to be able to express himself more ably by addressing the science directly, uncomplicated by feelings and fuzzy thinking.

  13. Trenberth on Tracking Earth’s energy: A key to climate variability and change
    To both: I assumed you knew where to find NASA data at http://discover.itsc.uah.edu/amsutemps/ where you can select "Sea Surface," then tick 2003 and 2011 and 'redraw." The above borehole plot over hundreds of years is irrelevant because it was probably at shallow depths where solar insolation had an effect. Note the yellow linear trend line on this, the deepest (9,000 metre) borehole, and note the intercept at the surface around 10 to 12 deg.C.
    Now you can see similar plots for hundreds of other boreholes using the link in (d) at (-link snipped due to antivirus security threats-) Suppose (-Off topic Gish Gallop snipped-)
    Response:

    [DB] Last warning about being off-topic.

    BTW:  Borehole data is at depth to avoid surface temp contamination of the data.  Which you would know if you had bothered to actually look at data that might confound your perambulations and not just cherry-pick the little data which may through happenstance support you.

  14. Venus doesn't have a runaway greenhouse effect
    30, Rosco,
    There has never been any demonstrated mechanism of trapping heat
    False.
    Even the stars have an energy input through gravity
    Misleading or misunderstood. See Kelvin-Helmholtz timescale. See nuclear reactions, the true source of energy in stars. But in a nutshell, for the potential energy of gravity to be converted to another form, work must be done, meaning the object must compress, which it cannot do indefinitely (for a star, it would "burn out" in mere 18 million years). Otherwise it is a perpetual motion machine that is creating energy and violating the First Law of Thermodynamics.
    ...there must be some source of heat that we don't know about.
    False
    I think...
    Fuzzy thinking of no value. What you think does not make it true. It does not create facts or truths, and is not a valid argument.
    We would still have the sun's input...
    Yes, about 241 W/m2 of solar input, which would bring the planet to 255K, when it is in fact at 288K. The question is how do we get that extra 33K? Answer: The Greenhouse Effect This is all very, very basic science. Please follow the links and read before posting further comments.
  15. Lessons from Past Climate Predictions: IPCC SAR
    Dana- So sensitivity is something models calculate...rather than being an input into the model. I can't see a reason offhand why I would need sensitivity as a term in a model...what I need is the solar in, IR out and terms for where the heat goes.. ( so much for ice melting, so much for heating the oceans, so much for heating the near surface air, accounting for water vapor movement and circulation and so forth) and at the end what is left shows up as an increased global average temperature... from which you can calculate "a" as a convenient understandable number?
  16. Trenberth on Tracking Earth’s energy: A key to climate variability and change
    Fourier already knew of the internal heat of the earth and noticed it was negligible. Two centuries ago.
  17. Trenberth on Tracking Earth’s energy: A key to climate variability and change
    DougCotton @193, the frictional heat generated by lunar tides has been well quantified. The energy dissipated by the M2 tide is approximately 2.4 Terrawatts. Assuming energy dissipation scales with the magnitude of the tide, that means the total energy dissipated by all tides is around 6 to 6.5 Terrawatts at most. In other words, the energy dissipated by tides averaged over the Earth's surface is at most 0.013 W/m^2. From there, a quick calculation with the Stefan-Boltzmann Law shows that at most, tidal energy could raise the Earth's temperature by only 22 degrees K above absolute zero, or raise the temperature by 0.0025 degrees K above the current Mean Global Surface Temperature of 288 degrees K. Of course, anyone who gave this casual thought already knew that the combined energy from tides and radioactive decay cannot significantly contribute to the Earth's surface temperature. If they did, it would be impossible for -89.2 degrees C (as it has in an Antarctic winter). Indeed, as the heat from the core is conducted equally in all directions, the necessary consequence of its being the major source of surface warmth would be that the surface would be nearly equally warm at all locations - ie, the tropics and poles would have similarly balmy (or frigid) conditions. But by all means, go ahead and believe the 0.013 W/m^2 of tidal energy is far more important than the (average) 240 W/m^2 of solar energy. Please do not let any fact checking disturb you from the fantasy land you are so keen on inhabiting.
  18. GHG emission mitigation solutions - a challenge for the Right?
    Scaddenp, I for one appreciate your efforts to elicit solutions to the political and philosophical questions. Far too often there is a presumption that those can be ignored. In your hypothetical we require state and federal support for lots of things like basic research, retraining for low power industry, adjustments for regions with transition difficulties, etc. Contrary to some, I don't see a more general federal role except for something as simple as possible, like the Hansen tax. It should take 5 minutes to figure out and pass the Hansen tax, instead there would be 5 months of wrangling producing a compromise that would not be pretty. But for the source changes you describe, the federal government has to be involved. The Hansen tax seems to be the least likely to get turned into a plate of sausage and beans. It also gives people the resources to becomes self sufficient It takes away incentives for "showcase" solar projects that don't work but do drive up prices. Silicon for solar does not have economies of scale as far as I can see. What does have economies of scale is large FF and nuclear power plants (perhaps unfortunate but it is a fact). Here's a quote attributed to Eclectic Magazine: "There are three kinds of people in the world, the wills, the won'ts, and the can'ts. The first accomplish everything; the second oppose everything, the third fail in everything" Most people are in the first category, but politicians are often in the third and push voters into the second. But high electric rates and a rebate offer certain opportunities for people. A smart grid offers others since preferential sources will be much cheaper. But local control and local entrepreneurship would put a very large number of people in the first category and away from the whims of the federal level politicians.
  19. Trenberth on Tracking Earth’s energy: A key to climate variability and change
    Trenberth's curved trend line for sea surface temperatures can now be extended with NASA data available to the end of August 2011. The trend passed a maximum a few years ago and has been declining since. That is why NASA data currently shows virtually all of 2011 below 2003 - the year 2003 was on the way up and 2011 on the way down. This is just one piece of empirical data which is in accordance with my group's theory that it is crust temperatures (themselves controlled by core temperatures) which are forcing climate, not solar insolation. Over the last two weeks I have been doing calculations on borehole data and this very convincingly supports the theory. We see different underground temperatures which are related to latitude, thus confirming that frictional heat (due to the moon) is being generated in the core, more at the equator than at the poles. There is further empirical support in the fact that, on the days when the sun is directly overhead in the tropics, whether 23 deg latitude or at the equator, the temperature varies with latitude. This would not be the case if solar insolation were the only factor. The variations with latitude correlate with the underground temperatures. Associated variations in the angle of the sun at different latitudes are not sufficient in themselves to explain the empirical data. In effect, the empirical data debunks the concept that climate is forced by factors involving solar insolation and atmospheric gases. Yes, indeed, it is the sun's heat which causes what is only temporary warming each day. Solar heat flows into the surface and back out again. The net flow is small, but the absolute flow each way is quite significant as you should know if you've ever burnt your feet on hot sand. Because that flow in and out is far greater than the net flow, equilibrium can be and is achieved between the surface and the first 1mm or so of the atmosphere. From there up, convection takes over. So, whilst core heat has helped build up the temperature of the atmosphere over billions of years, it now plays a supporting role, making it easier for the sun to warm the air when the surface is warmer, and harder when it is cooler. Some heat is retained in the surface, and especially the oceans, from local summer to winter. Our group's theory explains all the physical observations, including the extending of the day's warmth into the early evening and the warmer ocean in local summer. It takes only a very small percentage change in the temperature of the liquid core (~5700 deg.K) to give rise to the kind of variation we have seen since the Little Ice Age. And that is perfectly possible (and probable) due to the variation in total gravitational force from the moon plus the major nearby planets. Our theory is supported by the physically observed facts. The "consensus" theory is not supported by Trenberth's trend, nor by the magnitude of the variation in temperatures with latitude, nor by the very significant correlation between the extrapolation of underground temperatures (using only data from 200 metres or deeper - beyond the influence of solar insolation) to the surface and the local above surface stable base temperatures.
    Response:

    [DB] I'm not going to even begin to address all the nonsense presented here, but just some of the egregious:

    1. Provide a link to the specific NASA data which you claim supports your Sea Surface Temperature (SST) claim
    2. Provide a link to a reputable source showing that your use of the word "theory" instead of "hypothesis" can be supported
    3. As for latitudinal variations in the angles of the suns rays being insufficient to explains measured temps: get a grip.  The Earth has a large, moving body of water with a gaseous envelope surrounding that called the atmosphere.  They do stuff like rearrange heat within the system.  Get used to it.  Or prove that they don't.  The empirical data strongly supports the radiative properties of the atmosphere powered by the sun as being the thermostat regulating global temps.  It's just physics.
    4. Global borehole data, like SST data, does not support you:


    Global surface temperature change over the last five centuries from boreholes (thick red line). Shading represents uncertainty. Blue line is a five year running average of HadCRUT global surface air temperature (Huang 2000).

    Mr. Cotton, playing make-believe is all well and good when writing stories.  But for things in climate science the accepted practice is to use physics.  And here at Skeptical Science participants use the language of science and physics to explain climate science. 

    And it is those selfsame physics, based on more than 150 years of study and research (upon which our civilization is built) that says that your pet hypothesis (which is all that it is, not a theory) which you ignore.

    So by all means, play a 21st Century Don Quixote and tilt at windmills.  But unless you can express your points in cogent scientific fashion, which involves using physics to explain why those processes and metrics we can empirically see and measure work so well for everything our civilization depends upon, but do not apply to controlling global temps.  And the onus is on you to do it in step-by-step fashion on appropriate threads, or those comments deemed off-topic will be deleted.

    Until then the participants here will rightfully ignore you.

  20. Tar Sands Impact on Climate Change
    a sign of how truly addicted we are to FFs The fact that we blame the supplier rather than the person in the mirror is a sign of how truly addicted to FFs.
  21. Tar Sands Impact on Climate Change
    Albatross The Alberta government is not perfect. I never said it was. But flaring is a huge source of Greenhouse gas emissions. To thumb our nose while willing filling our gas guzzling SUVs with OPEC oil does absolutely nothing to stop global warming. None.
  22. SkS Weekly Digest #13
    Thanks Paul, It would be good to get a considered legal opinion on this (or are you qualified?) but I can understand the issue you raise. I do however see a potential solution. If the issue is "intention" as conveyed by context, presentation and impression as you argue then tt may still be possible to have all the toons grouped together under a single heading provided there was a suitable explanation which made it clear that the intent was not to promote any copyright infringement. This could be further enhanced by making the thumbnails on such a page link to the original source material rather than to the image itself. Up to the moderators to work it out I suppose but seems a pity not to provide such an excellent source to useful material.
  23. Venus doesn't have a runaway greenhouse effect
    DSL - point taken! Word-play is always dangerous ground. #30: Estimates of Earth's temperature without GHG's come in at well below freezing (IIRC ~-18C), mentioned in Chris Colose's article. The Sun does not provide enough energy this far away from it.
  24. CO2 is just a trace gas
    @Pete Dunkelberg #34: Other SkS authors are crafting the Intermediate and Advanced versions of this rebuttal argument. I'm not certain when they will be posted. The person behind the screen of the Science of Doom's website delves into this matter in excrutiating detail. Some readers of this comment thread may find the information posted on it to be of interest. The comment thread exchanges are also very illuminating.
  25. Venus doesn't have a runaway greenhouse effect
    Heard of insulation? Plain ordinary convention physics with 100 of years of experimental evidence has no trouble calculating the temperature on the surface of venus without any mysterious energy source. By contrast, your misunderstanding has a problem. If you look at the energy diagram you see the breakdown, but most importantly, this energy flows are measured. In your understanding, you could not account for these measurements. Do you agree that the test of whether the science is right is measurement? By all means come up with alternative physics but your alternative theory in which the GHE is missing must be able to account for what we actually observe.
  26. Venus doesn't have a runaway greenhouse effect
    There has never been any demonstrated mechanism of trapping heat - it is the engineer's dream to achieve this and increase efficency of machines. Even the stars have an energy input through gravity and if the assertions about Venus albedo being so reflective that almost no radiation reaches the surface there must be some source of heat that we don't know about. I think Earth's temperature would be about what it is plus or minus a degree or two. We would still have the sun's input and water.
    Response:

    [DB] "There has never been"

    Never?  In over 150 years of scientists researching the greenhouse effect?

    Honestly, you betray your extreme lack of knowledge with comments like this.  You are not doing well, here.

  27. Venus doesn't have a runaway greenhouse effect
    28, DSL, Rosco, I agree. I just looked around and came up with the same thread. The Planetary Greenhouse Interestingly, there's nothing better. No one else in the history of creative denial ever seems to have tried to argue that the greenhouse effect isn't relevant because convection + conduction does it all. Rosco, if you post a clear and concise argument on that thread (leaving out all of your observations that prove that conduction and convection exist, which is a strawman -- that is to say, an argument against something which no one is really contesting, and so of no value in advancing the discussion) then I will post a clear and reasoned response.
  28. Venus doesn't have a runaway greenhouse effect
    Watch that word "trap" sky--it's a denialist deviation point. I prefer "lengthen the path" of OLR. Rosco, what power are you assigning to convection? And are you implying radiative transfer has nothing to do with the average temperature of the Venusian atmosphere? Let's see some specifics on Venus, or take your theory over to the Colose article I linked earlier . . . please.
  29. GHG emission mitigation solutions - a challenge for the Right?
    Eric, firstly an apology. I actually regard you as the most honest skeptic here - you have an honourable record. I'll admit that my comment at the end was a dishonest goad aimed at getting a proper response from you. If I didnt value your opinion, then I wouldn't have been so interested in provoking it. You are also the only skeptic here to really address the political issues rather than just saying they support a technology without saying they would make the change. I was just hoping you might have different ideas based on the rights conflict. I would agree that reducing transportation full stop is a big way to improve efficiency (in my country 44% of GHG are from transport so bigger deal here), but if you can power that transport from non-FF source, then you arent under pressure to rearrange society. Unless world stays in really deep recession through 2012-13, watch the petrol price. "They have a long way to go however if they expect anything like a 200 to 60 drop in kWH/p/d". Cant be done on energy efficiency/reduction without really major social change. This is energy consumption at level of China, Chile, Latvia. Much easier to change source.
  30. Venus doesn't have a runaway greenhouse effect
    Rosco - you seem to disagree on the possibility that CO2 makes it more difficult for energy entering the climate system to leave that system. These energy forms are at different wavelengths and so CO2 affects one over the other. CO2 doesn't create energy on its own (nobody has ever suggested this), it just reduces the ability of the whole system to shed energy effectively. Since the only way the Earth's (or Venus') climate system can shed energy is by radiation, that is rather important. Please be courteous and read the links you were provided with earlier. Based on your postings I suspect you haven't. What temperature would Earth be, if the atmosphere was unable to trap any of the outgoing longwave radiation?
  31. Venus doesn't have a runaway greenhouse effect
    Rosco - try using the search button up top and posting on topic. But first read the articles - you need to learn some science to make sense. If what you post isnt relevant to venus, then I guess it will be deleted. If you want your articles read, then stick to the rules.
    Response:

    [DB] "But first read the articles"

    I can think of no better advice to give someone who is not yet doing so.  Thank you.

  32. Mythic Reasoning about Climate Uncertainty
    "Skeptics are less positive that we can predict the outcome." Do you think that is a reason for inaction? Uncertainty cuts both ways. It could be worse than the conservative predictions of IPCC.
  33. Venus doesn't have a runaway greenhouse effect
    Radiation is the only mechanism for energy into earth's atmosphere and out of it - no argument. I simply disagree with the assertion that in an atmosphere radiation is a dominant form of energy transport. (Off-topic snipped). (Off-topic snipped). (Off-topic snipped). (Off-topic snipped). (Off-topic snipped). (Off-topic snipped). (Moderation Complaints snipped). So be it - I simply think the case for the importance of radiation as the major means of distributing energy in planetry atmospheres is overstated - I see we are never going to agree on this point.
    Response:

    [DB] Portions of your comment not pertaining to this post (Venus doesn't have a runaway greenhouse effect) were snipped, as were complaints about moderation.  If you use the Search function in the upper left corner of every page, you will find about 4,000+ other threads here, many of which will be on-topic for a portion of your snipped comment.  Please make an effort to observe the topic of the post you are commenting on & ensure your comment is germane to the post.

    Note that complaints about moderation are always off-topic and force yet more moderation.  FYI.

  34. Tar Sands Impact on Climate Change
    Badgersouth: Both your links in #61 & 62 are to the same location.
    Moderator Response: Corrected.
  35. Tar Sands Impact on Climate Change
    Suggested reading: “Pray that naysayers are right about climate change,” David Horsey Cartoons and Commentary, seattlepi.com, Sep 1, 2011 To access this cartoon/article, click hhttp://blog.seattlepi.com/davidhorsey/2011/09/01/pray-that-naysayers-are-right-about-climate-change/ere.
  36. Lessons from Past Climate Predictions: IPCC SAR
    Dave123 - there is a difference between short-term sensitivity, long-term fast feedback sensitivity, long-term sensitivity including slow feedbacks, etc. Maybe that's what you mean? James Wight had an excellent post discussing the various measures of sensitivity which I linked at the end of this post (click the "fast feedbacks" link in the last sentence). Chris G - I know, and I very much agree that people disrespect models way too much. No model is perfect, but there's almost always something we can learn from a model. One of the main points of this series is to see what we can learn from them. Learning from past model flaws is why models keep getting better and better. Badger - I'm not sure what assumptions they made about ozone depletion. Ozone plays a relatively minor role in the greenhouse effect though. But if you're interested, they probably talked about it in Chapter 6. You can download the whole SAR WGI report by clicking the first link in the post.
  37. Lessons from Past Climate Predictions: IPCC SAR
    What assumptions about the ozone hole in the atmosphere over Antarctica are embedded in the SAR model and forecasts?
  38. Tar Sands Impact on Climate Change
    Suggested reading: “Looking beyond TransCanada’s summer of discontent Why excluding opponents to resource development is unwise,” by Doug Mathews, Alberta Oil, Sep 1, 2001 To access this article, click here.
  39. Lessons from Past Climate Predictions: IPCC SAR
    Oh, thanks Dana; I missed that. Looking... Really though, I wasn't targeting you, but rather the people who say things roughly like, your model is off by 0.2 C; therefore, all models are worthless.
  40. Lessons from Past Climate Predictions: IPCC SAR
    Dana- Then A can't be constant with time, because feedbacks will be changing with time...albedo for example. The more ice we lose, the more land/ocean exposed, the more heat absorbed. Maybe I'm just confused on what is partioned into A and what into dF. My naive interpretation of dF has been the difference between solar irradiance and IR leaving the earth.
  41. Pete Dunkelberg at 08:24 AM on 2 September 2011
    CO2 is just a trace gas
    Ken, I don't understand the 95 percent figure but we do have an interesting greenhouse environment that depends on both CO2 and H2O. H2O by itself tends to turn from vapor to liquid to solid. When it does this it drops out of the atmosphere and provides no greenhouse warming at all. CO2 stays in the air and provides enough warming to keep H2O evaporating and precipitating out in a cycle. See CO2: The Thermostat that Controls Earth's Temperature. However, as long as water is kept warm enough to keep our familiar water cycle going, it is in the air in much greater quantity than CO2 and provides about half the total greenhouse warming. Since CO2 and H2O intercept some of the same wavelengths one must be careful in calculating how much greenhouse effect to attribute to each. See The attribution of the present-day total greenhouse effect.
  42. Lessons from Past Climate Predictions: IPCC SAR
    Chris G -
    "To be fair, you should compare the accuracy of models predicting warming as CO2 increases with models that don't."
    Actually we've done that. Click the button at the top of the post to see all our entries thus far in the 'Lessons from Past Climate Predictions' series. Easterbrook's cooling prediction is probably the most relevant. We also compared his prediction to Wallace Broecker's 1975 warming prediction in the Broecker post in the series. The purpose of this series is to fairly examine each warming or cooling prediction we can find and see where each went wrong and what we can learn from them. I'm also writing a book/booklet on the same subject.
  43. Lessons from Past Climate Predictions: IPCC SAR
    My pleasure john. I also drafted up a post on the IPCC TAR which will be published in the near future. Matching the projections to observations yields a sensitivity of about 3.4°C for 2xCO2 there. Funny how we keep getting these same answers around 3°C, and yet the "skeptics" are certain sensitivity is somehow much lower than that. Either there's something very wrong with climate models, or something very wrong with Spencer and Lindzen et al.'s claims. Personally I'd put my money on the latter.
  44. Lessons from Past Climate Predictions: IPCC SAR
    Regarding linearity, I don't know of anything that is linear in the climate system, but, as any student of calculus knows, you can approximate any curve with line segments, and the shorter the segments, the less the error term. So, sure, I'd be very surprised if there were a constant (linear) relationship between CO2 and temperature over the range from slushball to ice-free states of the earth. However, given current orbital parameters and the positions, sizes, and shapes of the continents, and the current state of ice masses, it is possible to quantify a linear relationship that is good enough for the near future. WRT, "models are inaccurate", I think it was Gavin at RealClimate who pointed out that all you had to do to prove any model wrong was demand more accuracy out of it than the authors were able to code into it. That's the nature of models; all models are approximations. To be fair, you should compare the accuracy of models predicting warming as CO2 increases with models that don't. Shall we take a wild guess which set yields a better approximation of reality? Model factors are wrong, whatever. It's like a teacher (which in this case is history, not any of us) giving partial credit if the student shows their work on a long problem and the teacher is able to determine their answer world have been correct if they hadn't made a mistake at point X. If there are only one or two points, that somewhat validates the rest of the work. It's a little frustrating to see so many attacks on models because, AFAIK, all models with a halfway decent hindcasting ability predict continued warming under BAU. It doesn't really matter if we reach 4 degrees by 2100 or 2075; at some point we will cross a threshold beyond which the population can not be supported. It is going to continue to get warmer until we either switch to alternatives as our primary energy sources or society collapses.
  45. CO2 is just a trace gas
    Ken @ #35 "How about some complete science here! What happened to water vapor on Table 1? Water vapor does represent 95% of the greenhouse gases and..." For completeness, 95% of what? It isn't 95% of the natural greenhouse effect as CO2 provided 20% of that (7oC of 35oC). Are we then back again to the 'biggest volume matters most' argument? If so, it's ironic because that is the exact opposite of what is up for discussion here.
  46. Lessons from Past Climate Predictions: IPCC SAR
    Thanks for this Dana, have been trying to work out how to put all this into an explanation of how comparing models with observations gives us more understanding of the 3DegC sensitivity, The model update 2010 at RC also shows 3.3DegC sensitivity. appreciated.
  47. Lessons from Past Climate Predictions: IPCC SAR
    Dave123 - not sure what you mean about the independent estimate of the climate sensitivity. To your second question though, feedbacks are built into that sensitivity parameter. That's what "a" tells you - for a given radiative forcing, how much the temperature will change, including feedbacks.
  48. Michaels Mischief #2: Opposing Climate Solutions
    This is quite a good article about Solyndras troubles: http://www.compoundsemiconductor.net/csc/news-details/id/19733965/name/No-surprise-with-CIGS-startup-Solyndra-shutdown.html It was an interesting idea and some other company may take the product on and develop it further. There will be a lot of companies created and disappearing in the solar PV business, because the technology is in its infancy (despite years of stagnation in innovation). There is so much research in this field now, that there will be a lot of changes over the years, making it difficult for companies to stay ahead for long.
  49. Michaels Mischief #2: Opposing Climate Solutions
    Badger@14 Solyndra produces a non-standard product. Their idea is/was to produce 'racks' of tubes with i think thin film solar sells stuck in the inside of the tubes. The tubes are open at the top and the idea was the sun could hit the cells inside at any angle. The racks didn't need to be fixed to the roof (primarily flat rooves) because the gaps between the tubes allowed air to pass through so that there was less resistance. The company web site is still up and running, so they aren't totally dead. But not all ideas and start ups succeed.
  50. Lessons from Past Climate Predictions: IPCC SAR
    Dana- For my own preparedness I'm not clear on two things- The independent estimate of "A" the climate sensitivity factor. and why is this a linear equation? Off hand, given feed backs from changes in albedo as ice melts etc, would be non-linear, and as ice disppears from a region you lose the heat of melting. Or is that all taken into account in the construction of the radiative forcing? All definitional stuff I know... but I think clarity on the origin of the radiative forcing factor in current models might hep Yvan.

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