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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 76101 to 76150:

  1. Lessons from Past Climate Predictions: IPCC SAR
    Sure Wombat, happy to. The relevant formula is dT = a*dF where dT is the change in temperature, a is the climate sensitivity parameter, and dF is the change in radiative forcing. In the SAR case, for dF = 4.37, they found dT = 2.5°C. So if we plug that into the formula: a = dT/dF = 2.5/4.37 = 0.57°C per W/m2 So for every 1 W/m2 forcing, the model results in 0.57°C warming. If we then use that climate sensitivity parameter to calculate what temperature change we would expect from the forcing associated with a doubling of CO2 (3.7 W/m2), we get: dT = 0.57 * 3.7 = 2.12°C What the SAR did was to overestimate how much of an energy imbalance is caused by a doubling of CO2. As a result, they also overestimated the temperature change in their model resulting from that doubling of CO2. And so they thought their model was more sensitive to CO2 doubling than it actually is. An important distinction is that they overestimated the model sensitivity specifically to doubled CO2, because they overestimated the forcing associated with doubled CO2. But the sensitivity parameter (0.57°C per W/m2) remains unchanged. Clear as mud?
  2. Michaels Mischief #2: Opposing Climate Solutions
    #9 Ahhh, but if there were NO cars, and public transport improved five-fold as a result, you would indeed be able to 'hop-on-hop-off' public transport to complete your errands. Personal vehicles are an unsustainable indulgence, purely because of the resources they consume, never mind the degredaton of the atmosphere, climate, vehicle accidents and hospital costs, etc etc etc. But yeah, in the ABSENCE of an effective public transport system, EV works 'better' than ICE.
  3. Venus doesn't have a runaway greenhouse effect
    I don't dispute that CO2 absorbs infrared energy and increases in temperature. But an equilibrium point is reached where input equals output and no further heating can take place without further energy input.
    Perhaps you are not familiar, then, with that giant ball of burning gas one sees in the sky during the day? The one that is constantly bombarding the Earth (daylight side) with energy...
  4. It's not bad
    Joseph#152: By definition, a cherry pick is the use of a small subset of the available data, usually to draw a pre-conceived conclusion. This is only a 'disconnect' for people who keep score based on who said what when. Those who understand the comment made by Hardy can see that such a prediction is justifiably updated by more complete analysis. This is the normal process of science or for that matter any predictive endeavor. BTW, setting up a misrepresentation of another's argument so it can then be shown as a potential 'disconnect' is known as a strawman. In this case, 'they got the date the glacier would melt wrong' is a strawman. It is far more productive if we engage in substantial issues.
  5. Michaels Mischief #2: Opposing Climate Solutions
    Pete - some days I just ride my bicycle. Where I live it never gets quite cold enough that I can't ride my moped. Sometimes I ride in the rain, and sometimes I carpool with my wife if it's raining too hard.
  6. Pete Dunkelberg at 10:13 AM on 1 September 2011
    Michaels Mischief #2: Opposing Climate Solutions
    dana @ 3, "I commute to work most days on an electric moped...." I'm interested in getting something like that. So what stops you other days? Rain? Cold? Both?
  7. Venus doesn't have a runaway greenhouse effect
    14, Rosco, Latent heat: As long as water vapor stays as vapor, it remains as kinetic energy in the water vapor. When that water vapor condenses, that energy is passed to other molecules in the surrounding atmosphere. This serves to transfer some energy from the surface higher up in the atmosphere, an amount that has been measured and quantified and is roughly 1/5th that which is transferred through radiation. What's your point? Badly burnt: You do this a lot. You seem to have a personal need to correlate all concepts to personal experience, and then you make the mistake of performing value comparisons based on such experiences. That you can be burnt by a hot object says nothing. How does a glowing ember cool... by radiating the heat, or by conduction, heating all of the air around it purely through contact? If you put your hand near but not on a burning ember, do you feel the heat? How, if you aren't touching it? No, it's not because it has heated the air (it has, but not that much, and you wouldn't feel the heat emanating from the object). You are directly feeling the radiation. When the sun hits your face, do you feel the heat? Radiation. Oxygen and nitrogen: I didn't say they don't get hot, that's absurd. I said they don't appreciably emit that heat as radiation in quantities and time scales that are relevant to the current atmosphere, as compared to CO2 and H2O. In a pure O2/N2 atmosphere that radiation would be the only way that the atmosphere can cool. In our atmosphere, O2/N2 act instead as a buffer. Why do you think down vests are so warm? Why is all insulation primarily pockets of air? Shimmering: You're doing it again. You can see it, so it must be more important than radiation. This is not a viable or effective argument. But, interestingly, you are wrong here. The air near the ground is being heated through radiation which is absorbed by the H2O and CO2 in the atmosphere, and then conveyed to the O2 and N2 through collisions. More heating occurs closer to the surface, and enough to cause changes in air density which produce the shimmer. This is not occurring through conduction, even if you imagine that to be the case because the layer of air is close to the surface. Radiators: Proving that conduction exists does not prove that it is the primary mechanism in heat transfer in the atmosphere. Again, you are wedded to what is familiar to you, and dismissing anything that is too abstract for you to consider. This mindset is a trap. Oxygen/nitrogen radiation: Look up the numbers. Look at this spectral analysis and this one. Really, do you think science is done by just squinting one eye and sort of guestimating everything? Everything radiates in proportion to its temperature: No!!! This is true on a macroscopic level, but it is not that simple. On the molecular and subatomic level, quantum mechanics interferes. Things absorb and radiate only in specific wavelengths, and that greatly complicates the interactions. You have a lot of studying to do. This is a denier site, but a lot of the science is very good and accurate. Try starting there. To imply otherwise is in contravention of physics.Okay, this is getting silly. If you have real questions and want to learn, I will help. If you want to just spout nonsense and dig in your heels, do it on your own... but find the proper thread for it. This one isn't it.
  8. Sceptical Wombat at 10:09 AM on 1 September 2011
    Lessons from Past Climate Predictions: IPCC SAR
    However, the SAR used a radiative forcing of 4.37 W/m2 for a doubling of atmospheric CO2. The IPCC TAR updated this value five years later with the value which is still in use today, 3.7 W/m2 (see TAR WGI Appendix 9.1). Since the SAR overestimated the energy imbalance caused by a doubling of CO2, they also overestimated the climate sensitivity of their model. You appear to be saying that the SAR overestimated the climate sensitivity of their model and therefore underestimated the global temperature change. This is a bit counter intuitive. I'm sure that there is a perfectly good explanation but could you please elucidate for my benefit?
  9. It's not bad
    No cherry picking, as a matter of fact your posting goes to my point! When scientists don't have all the data or all the variables and they make forecasts based on that, then that disconnect is created. Again this is not to say that global warming is not happening, or is not melting Kilimanjaro's ice, it just says that maybe there is a disconnect between currents trends vs. projections.
  10. The human fingerprint in the daily cycle
    Here is some actual empirical evidence giving a reasonable alternative explanation for the decrease in DTR over the last few decades. It is manmade but not CO2 emissions. The effect of decreased DTR is most noticeable over land areas and this article also explains this. Scientific explanation for decrease in DTR. From this article my DTR change for Omaha Nebraska (Post # 101) as compared to the long term norm makes a lot of sense now.
  11. Venus doesn't have a runaway greenhouse effect
    Sphaerica Where does the latent heat go ? If radiation is so powerful why is it you get really badly burnt when you touch a hot object while you can stand near it for long periods ? What special properties do oxygen and nitrogen possess that allows them to defy the laws of physics ? You don't believe oxygen and nitrogen get hot ? Then hot air balloons are really hot "greenhouse gas" balloons ? What is the shimmering you see rising from hot bitumen during the day - radiation ? I don't think so - it is diffraction caused by the rapid movement of heated air convection reducing the local viscosity of the air through convection. Even a car's radiator doesn't work by "radiation" - it works by conduction as the water absorbs the engines heat and then by conduction and convection as the air passes over it. Stop the car, leave the motor running and disconnect the fan and see how effective radiation is at removing heat. I'll see you at the mechanics as you try to explain why it shouldn't have destroyed itself through overheating. How do you know oxygen and nitrogen don't radiate in relevant amounts ? So when I'm in the shade in the desert with air temperatures of 45 +C and low humidity it is radiation it is the 0.04% CO2 which is heating me up ? Everything radiates in proportion to its temperature - including oxygen and nitrogen and CO2. The theoretical explanations of bond stretching and vibrations associated with triatomic molecules does not imply they radiated in excess of their temperatures - it is an attempt to explain their absorbtive properties nothing more. To imply otherwise is in contravention of physics.
  12. Venus doesn't have a runaway greenhouse effect
    10, Rosco, I would very, very highly recommend reading Spencer Weart's A Discovery of Global Warming. Really. It is very worth the time.
  13. Venus doesn't have a runaway greenhouse effect
    10, Rosco,
    I get the geometry I just think it isn't relevant for a dynamic system.
    This is a nonsensical statement. I'll be happy to help explain it, but you need to be a little more clear. I don't think you truly understand the geometry, or how it applies, if you think it's not relevant.
    I believe...
    Look out for everything like this. Fuzzy, unquantified, "common sense" thinking is dangerous. It leads to very false but easily accepted conclusions. "I believe" means "I don't really, perfectly understand, but it feels good." But obviously what you are saying in this case is true, the planet does store energy in the day and release it slowly at night. But what's your point? How does it apply? Again, the greenhouse effect is what permits this to happen effectively. Look at the moon, where the moment the sun sets, the temperature plummets. It's wrong to just think it "stores enough" in a vague, wave-of-the-hand sense.
    ...but from the whole atmosphere - oxygen and nitrogen included - which primarily becomes heated by conduction and convection...
    No. This is wrong, and a common denial trope, putting everything on conduction and convection, without quantification, because they are effects you can feel and are familiar with. Oxygen and nitrogen do not radiate in relevant amounts, because of their molecular properties. Radiation far outweighs convection and conduction. This has all been quantified. There's no reason to just visualize it the way you'd like.
    ...the latent heat water vapour carries...
    No. Water vapor doesn't just carry around latent heat in the fashion you imply, and the specific heat of water is not relevant in this instance. Again, you're throwing around scientific terms without properly applying them. Specific heat is not a factor. Latent heat is only relevant for the transfer of some heat from the surface to the troposhere. You have a lot of misconceptions... enough knowledge to be dangerous, so to speak. I suggest you take the time to visit reputable science and climate science sites to learn this properly, beginning from the understanding and position that you do not know and you need to open your mind and learn. If you close your mind by thinking that what you know (and misunderstand) applies (because you misapply it), you will be stuck where you're at.
  14. Venus doesn't have a runaway greenhouse effect
    Sphaerica "The greenhouse effect works exactly by trapping and accumulating heat, as you well know" I don't know that at all. Nothing else in the Universe accumulates heat without an energy input. Everything is perpetually cooling down and the hotter it is the faster the rate of cooling - at least I think that is what Newton said. I don't dispute that CO2 absorbs infrared energy and increases in temperature. But an equilibrium point is reached where input equals output and no further heating can take place without further energy input. So with no other energy source the maximum "blackbody" temperature of Venus with 2644 W/sq m input is about 465 K. It is remarkable that as the space probes passed through Venus's atmosphere they recorded temperature and pressures that are approximately what one would expect compared to Earth. This factor is the fourth root of 1.91 - 1.176.
  15. 2010 - 2011: Earth's most extreme weather since 1816?
    Adelady, I think you may be under a slight misapprehension regarding the rainfall event in Toowoomba. This was NOT the first time by any means that such rainfall has occurred there. The flooding was because of major changes in re-engineered creeks, the insertion of smaller pipes to drain some (one in particular) park areas. Older residents remember flooding as large as 2011 but of course in earlier days the information was much more contained in the area. Grantham was a new experience but the toal anmount of water was not very new and later constructions of raods and railways played a large part in directing higher flooding there also. A second impoortant point about the Brisbane area flooding is that it was all much les, as in some metres lower, than in 1843 and other earlier years of the 19th century and also than both 1893 and 1974. This is in spite of the fact that construction of roads and buildings has caused very different channelling of the water. Other flooding in Queensland, while quite significant, was certainly NOT unprecedented. John Nicol jonicol18@bigpond.com Brisbane
  16. Michaels Mischief #2: Opposing Climate Solutions
    Re #7: Ah, but for some of us public transportation is not a valid option while an EV would be fantastic. For instance, my commute is only about 10 miles each way, but due to the lousy bus system out here it would take me nearly an hour and two different buses each way to commute via mass-transit. Add to that the need to run errands after work (imagine trying to make 2-3 stops with buses this bad) and the public transportation option is simply out of the question. On the other hand, were I able to afford to swap out my current 30mpg compact for a Volt I'd rarely even use the ICE and it wouldn't inconvenience me in the slightest.
  17. 2010 - 2011: Earth's most extreme weather since 1816?
    It is fairly obvious that if the global climate is in a particular condition, such as occurred during each of the ice ages, during the Maunder minimum and the Medeaval Warm period, or during each of the Holocene periods between the coldest years, that ALL of the countries on earth will experience similar changes as shown in Figure 1. What is also remarkable from that figure is that most of the countries cited are in near tropical regions, whereas, the suggestions from all models supporting the IPCC has been, I believe, that the colder latitudes will show the greatest increse in temperature. Poland appears to be the only significant outlier from this observation, and it appears at the lower end of the scale. Since one of the key factors defining weather or climate, and one which is clearly measureable without much massaging, is precipitation, it is very surprising to see Figure 7 here being held up as a demonstration of "extreme" weather. As shown, in the last 100 years, the bunching of more "extreme" years is actually in the 1950s, with something of a decay in that condition thereafter. The peak rainfall in 2010 is only marginally higher than about 1918 and 1951 and is slightly less "extreme" than the dry year of about 1902. John Nicol jonicol18@bigpond.com
  18. Venus doesn't have a runaway greenhouse effect
    For clarification I am not denying the physical properties of CO2 to absorb infrared radiation - I accept that without doubt. I don't claim to know why Venus is 730 K. But I do there are some claims made about the greenhouse effect that make little sense to me. Why is it valid to reduce solar insolation by a factor of 4 to calculate the "effective blackbody temperature" of a planet - especially Venus with it 200 odd earth day long day ? I get the geometry I just think it isn't relevant for a dynamic system. Parts of the earth receive way more than Kiehl & Trenberth's average 235 W/sq m. Parts get almost zero except by ocean and atmospheric circulation. I believe the oceans, and to a lesser extent the atmosphere, store enough energy during the day so that when the sun sets (or the earth turns if you prefer) and the energy really starts to escape to space the ocean and atmosphere radiate relatively slowly so that before we turn into a block of ice we get our next fix the next morning. The downwelling longwave radiation measured in the atmosphere is not only from CO2 and water vapour but from the whole atmosphere - oxygen and nitrogen included - which primarily becomes heated by conduction and convection. At 0.04% of the atmosphere CO2 radiative effect is small - real but it must be in proportion to its concentration. It has a specific heat of less than 1 J/gram. Water vapour, which is at least 60 times more abundant in the average atmosphere has a specific heat of double that but it is the latent heat water vapour carries, which CO2 doesn't, that makes it the driver of the climate - some 2400 J/gram. So - i know this is off topic slightly but it is relevant. Perhaps the water on Venus did disappear as postulated - I don't claim to know.
  19. Venus doesn't have a runaway greenhouse effect
    8, Rosco,
    I realize that the claim is it accumulates but isn't that what I said in my proposal for an energy source which everyone laughed at.
    No. What you said was that it would accumulate, then you implied that this accumulation would be generative... that you could proceed to take out more energy than was being put in after it had accumulated. If you meant that we could only take out the energy that was put in, then what was your point? You described a new form of battery. The greenhouse effect works exactly by trapping and accumulating heat, as you well know, and the disparity in the numbers is not an issue. 132 can lead to 16,100, and you already answered why yourself. If the system takes in 132 every day, and emits 131.9999 every day, then after 10,000 days the temperature has raised 1 degree. Some 160,000,000 or so days later, the surface temperature reaches 730K. There's nothing at all illogical or impossible behind this. Simply declaring that you find it incredible is neither evidence nor argument, but nothing more than mere obstinacy. I find such a position to be unworthy of discussion.
  20. Michaels Mischief #2: Opposing Climate Solutions
    Why in the world does Pat Michaels have a blog at Forbes? Do they actually pay him? And even given that he has a blog, why would they let him write about renewable energy? Honestly, one could come up with about a thousand (or ten thousand) others who are far more knowledgeable. Nevermind. Forget I asked...
  21. Venus doesn't have a runaway greenhouse effect
    I realize that the claim is it accumulates but isn't that what I said in my proposal for an energy source which everyone laughed at. If it is possible to accumulate energy as postulated for Venus then my proposal is equally valid.
  22. Venus doesn't have a runaway greenhouse effect
    The criticism of my proposal is obviously right - it can't work - you always get less out than you input - unfortunate but true. The following is from a University lecture about the greenhouse effect on Venus :- "From geometry, we can calculate the average solar flux over the surface of Venus. It is approximately 661 W/m2. Venus is very reflective of solar radiation. In fact, it has a reflectivity (or albedo) of 0.8, so the planet absorbs approximately 661 X 0.2 = 132 W/m2. By assuming that the incoming radiation equals the outgoing radiation (energy balance), we can convert this into an effective radiating temperature by invoking the Stefan-Boltzmann law (total energy = σT4). We find that T=220 K. But Venus’ surface has a temperature of 730 K!!!" Do a little reverse maths - climate scientists tell us this is right - raise 730 K to the power of 4 multiply by 5.67 by 10 to the -8 (Stefan-Boltzman) and you get a radiative flux of 16,100 W/sq m. Where does this come from when a University Professor tells me the sutface of Venus receives only 132 W/sq m ? I think this is a fair question. If it is from the greenhouse effect how did this develop initially ? 132 W/sq m couldn't possibly do it. Venus has something going on that we don't know about - probably vulcanism, possibly high nuclear radiation - who knows. But I do know Venus is closer to the sun so that it receives nearly twice the irradiation that Earth does, it rotates slowly in the opposite direction to Earth and has enormous temperatures and pressure. Sphaerica, my point is what possible sensible physical principle can explain 16100 W/sq m radiative flux from an input of a mere 132 W/sq m ? It cannot possibly be due to the the greenhouse effect which is simply that CO2 absorbs infrared radiation from the surface of the planet because everything in the Universe radiates proportionally to its temperature so a runaway greenhouse simply doesn't add up - 132 in 16,100 out does not add up. Even if you assume all the solar radiation of 2644 W/sq m top of Venus atmosphere made it to the surface it is still a factor of 6 out. Seriously, I do not believe a runaway greenhouse effect as supposed can possily exist as described for Venus but I am open to convincing. Can anyone offer a valid explanation how the greenhouse effect can accumulate more than 100 times the energy entering a system and contain it ? I didn't find the professors explanation very convincing.
    Moderator Response: The energy accumulated. It did not all appear at once.
  23. Lessons from Past Climate Predictions: IPCC SAR
    "So to summarize how we can show the excellent quality of the SAR projections, we simply need adjust the slope and offset of the the SAR projections to match the observed data."
    I didn't say the SAR projections were "excellent quality". In fact I basically said the opposite:
    "The SAR projection of the warming over the past two decades hasn't been terribly accurate"
    The purpose of adjusting the slope (sensitivity) and offset (baseline) is to see what model parameters would have made accurate projections, not to say the model and parameters were accurate.
  24. SkS Weekly Digest #13
    Added: If you scroll to the bottom of the climate graphics page at the time I am posting this, the graphics are 'published' using this creative commons license: http://creativecommons.org/licenses/by/3.0/ This is only possible because John and other SkS authors are the authors.
  25. SkS Weekly Digest #13
    The graphics provided by John and others are licensed for general use in presentations and anything I think. This is possible because John and others are the authors of the works. If you make use the cartoon above, you would need to check the license. I don't know what that is. The owner of a 'property' decides how it can be used. The issue isn't the ability to copy, the issue is the intent of the owner or author. That is the same throughout all copyright law. Ease of copying doesn't give you any rights to copy.
  26. Sea level rise is decelerating
    Thanks for fixing the tags.
  27. Sea level rise is decelerating
    From time to time I have e-mailed some of the principle names in Climate Science with a specific question but mostly I don't want to waste their time and I don't expect a dialog with them although it did happen once. Furthermore they don't show up on blogs, if they do it isn't under their own name. I most certainly am not going to e-mail John Church to criticize his paper. I don't consider Tamino a principle or objective.
    Response:

    [DB] "I don't consider Tamino a principle or objective."

    Well then, let me ask you this: 

    How many legs does a dog have if you call the tail a leg?

    Four; calling a tail a leg doesn't make it a leg. (Abraham Lincoln)

    Discounting Tamino's analysis because you don't like it or don't consider him objective doesn't detract from the fact the Tamino is a professional time-series analyst whose work in climate science not only stands the test of time but is widely considered a de facto standard in climate science.

    Yes, Tamino can be irrascible.  Mostly that stems from those who refuse to learn, have a large vein of Dunning-Kruger running through them and those slander working climate scientists.  We are similar in that regard.  But again, that does not detract from his work.

    If you have issues with the work that forms this post, take it up with him.  If you have questions regarding the work of Church & White, take it up with them (I have yet to find a climate scientist unwilling to help those with genuine questions about their work).

  28. Dikran Marsupial at 06:37 AM on 1 September 2011
    Settled Science - Humans are Raising CO2 Levels
    Stephen Baines wroe "DM...A skeptic could always argue that we simply don't know all the terms well enough to do a proper mass balance." Yes, they could say that, but they would be wrong, the mass balance argument only requires estimates of anthropogenic emissions (which are taxed, so our estimates are pretty reliable and if anything an under-estimate) and observations of atmospheric CO2 (even WUWT accept that the Mauna Loa record is accurate). If the skeptics can't accept that, they will have no problem not accepting isotopic arguments either.
  29. Mythic Reasoning about Climate Uncertainty
    rcglinski#50 I don't understand what you're objecting to. Translate the IPCC statement into numbers if you like: There is a 90% or better chance that 51% or more of the observed increase in global average temperatures since the mid-20th century is due to the observed increase in anthropogenic greenhouse gas concentrations. The meaning is clear. Of course, 'most' is probably higher than 51%. But that is worst case; where's the problem?
  30. Dikran Marsupial at 06:22 AM on 1 September 2011
    Mythic Reasoning about Climate Uncertainty
    trunkmonkey wrote: "We have seen the models founder at the decadal time scale... " Well duh! Of course they founder on a decadal scale because on a decadal scale what you see is dominated by chaotic features of internal climate variability, not the effects of the forcing. Only someone completely ignorant of the workings of climate models would expect models to perform well on a decadal timescale or very small spatial scales (e.g. station data). Models are just getting to the point where decadal predictions may be worthwhile, hence the next IPCC report is likely to mention them as an active area of research. See this thread at RealClimate So, exactly what was the point you were trying to make when you wrote "the models founder at the decadal timescale"?
  31. Lessons from Past Climate Predictions: IPCC SAR
    I agree that there is no need to get wrapped up in baselines, but it is also good practice to give basic information about what one is presenting. A simple "SAR projections have been offset such that the 1990 projection is equal to the GISS Temp 5 year running average in 1990" would have been sufficient, either in the main post, or in response to my question about baselines. (both the 1990 5 year running average and the 5 year gaussian smooth are 0.27 C, so your plot of projections is a bit low). ====================================== Since offsets or baselines don't matter, and the SAR projection is pretty much nothing but a straight line 1990-2010, then perhaps the most useful comparison would be simply to look at the 1990 to 2010 slopes. The SAR projection extended to 2100 is 1.5 C rise in 110 years, or 0.136 C / decade. The observed GISS land-sea global temp from 1990 through 2010 is 0.194 C/ decade. (per Excel linear regression Slope function). So the observed slope is 0.194/0.136 = 143% of projection. For the best match, we would simply increase the SAR projections by 43%. Treating the stated sensitivy of 2.5C/doubling as 2.12C, and then increasing that to 3 C/doubling is the equivalent of increasing the slope of the SAR projection by 3/2.12 = 42%. Not quite the perfect after-the-fact adjustment, but pretty close. So to summarize how we can show the excellent quality of the SAR projections, we simply need adjust the slope and offset of the the SAR projections to match the observed data. ============================== Regarding the F2x value ..... AR4 shows a range from 3.09 W/m2 for MIROC3.2(medres) up to 4.06 W/m2 for GISS-ER and GISS-EH. So the 3.7W/m2 is by no means the last word. The AR4 table equivalent to the TAR WGI Appendix 9 reference of the headpost is AR4 WG1 Chap 8, supplementary table S8.1. At the very end of (large pdf) AR4 WG1 Chap 8, supplementary info.
  32. Lessons from Past Climate Predictions: IPCC SAR
    Charlie, there's no point in getting wrapped up in baselines. The baseline doesn't mean anything, it's just an arbitrary offset. All I did was offset the SAR projection in 1990 to match the GISTEMP 5-year running average value in 1990 (approximately 0.25°C). What matters are the temperature changes from 1990 to 2010, not the arbitrary baseline selection.
  33. Lessons from Past Climate Predictions: IPCC SAR
    By "Figures 5 and 6 use the GISTEMP baseline" I assume that you mean the 1951-1980 baseline, correct? There are many ways to adjust the baseline of the SAR projection to match the 1951-1980 baseline of the observed data. One method, which generates the best match between projection and observations is to wait until the end of the observation & projection period, and then go back and adjust the mean of the projection so it is equal to the actual observed mean temp over the projection period. It does appear that the 1990 SAR projection has been adjusted upward such that the mean projection matches the 0.424 C 1990-2010 mean of the GISS measured data. Is this what you did? Or is there some other calculation you used to change the 1990 SAR projection from the 0.00C shown in Figure 4, to the approximately 0.25C you show in Figures 5 and 6 ?
  34. CO2 is just a trace gas
    There are many other examples. The generally accepted safe limit for lead in soil is around 300 ppm. More at ClimateBites.
  35. Sea level rise is decelerating
    I went through the tide gauge data set section of Estimates of the Regional Distribution of Sea Level Rise over the 1950–2000 Period I gleaned some numbers for my spreadsheet and put them into tabular order as follows: Record..Status..........Reason 1159....RLR 1950....Met -256....eliminated......Records >2 years -1063...eliminated......Redundant -95.....eliminated......beyond TOPEX/Poseidon range -37.....eliminated......<250 km to Alt grid point. 1658....records for further assessment. ??......eliminated......Disagreement nearby records ??......eliminated......Locations ??......eliminated......Fragmented ??......eliminated......Noise ??......eliminated......Residual trends <10 mm/year -713....Eliminated......For above 5 reasons? (1658-945=713) 945.....combined -491....eliminated......by combination 454.....records for further assessment. -28.....eliminated......No useful data 426.....records for further assessment. Comments: Really, because Topex/Poseidon didn't cover the range they tossed the data? I don't think that makes sense, but I suppose there's a reason for that. In the text they go from 1658 records down to 945 records but don't give us any numbers as to how many were eliminated for the five reasons tabulated above. Residual Trends <10 mm/yr is reasonably objective. The other four listed are somewhat subjective without any guidelines as to what constitutes unsuitable locations, too much noise, too much fragmentation, or how much disagreement with other records is allowed or how near by they must be. After combining the 945 records there was another group of records eliminated for having no useful data. What was not useful? Perhaps in the data file that defies downloading for me, that is spelled out and each and every deletion is annotated as to how the criteria were met. As it stands right now and as far as I’m concerned, there is room for some subjectivity in perhaps several hundred deletions of data. A simple analysis of the data yields one thing, and the process along with the above editing criteria yields the opposite. Now even though there's a difference in sign, if the two time lines were close no one would care, but as you can see, they're not. The above is not the same as Reconstructed GMSL for 1880 to 2009 Which is linked at the top of this page but the treatment of the data is likely to be similar.
    Response:

    [DB] Fixed tags.

    The most likely reason for your lines diverging is that you are doing something wrong.  I suggest you contact Dr. Church or Dr. White (or Tamino, as this is his post) for advice.

    That would be the skeptical thing to do.

  36. Mythic Reasoning about Climate Uncertainty
    @ 28 muoncounter "Why not? If I need to run an economic model, telling me that an event has a 65% chance of occurrence is an input to an expected value calculation." This is an example of a situation where specifying the number does remove the ambiguity. You can't run an economic model off of "pretty sure." You need 65%. The number really means something. If you thought it was actually a 63% chance you'd use that number. Contrast to the IPCC. If they were to define "very likely" as 88% instead of 90% nothing really changes. The intent isn't to say there is actually a 90% or 88% chance that something is right. You're not adding information by citing a number the way you are in the example you gave.
  37. Mythic Reasoning about Climate Uncertainty
    critical#45: Trenberth: Increasing concentrations of carbon dioxide and other greenhouse gases have led to a post-2000 imbalance at the TOA of 0.9±0.5 W/ m^2 Hansen: ... that Earth is absorbing more energy from the sun than it is radiating to space as heat, even during the recent solar minimum. The inferred planetary energy imbalance, 0.59 ± 0.15 W/m^2 during the 6-year period 2005-2010, confirms the dominant role of the human-made greenhouse effect in driving global climate change. There may be differences in the numbers, but there is minimal uncertainty as to the mechanism and the cause. As Denning says, physics doesn't care what you believe. Arguing over the last decimal place is silly; it's real, it's happening. Stop denying that and do something about it. That we do nothing but wait until we 'can get more data' is ultimately the harm done by those who trumpet 'uncertainty' as if it is a red light.
  38. Lessons from Past Climate Predictions: IPCC SAR
    Figures 5 and 6 use the GISTEMP baseline. The GISTEMP smoothing was done with the Excel "smooth" function. The Figure 5 caption explains what it's comparing.
  39. Lessons from Past Climate Predictions: IPCC SAR
    What are the baselines for the lines in Fig 5 and 6? Figure 4, from the SAR starts with a reference point of 0 C in 1990. In Figure 5 and 6 you start at about 0.25C in 1990. What did you use for the offset baseline for the GISS data; and was the smooth a particular function or just a hand drawn approximation? Figures 4 and 5 are nice comparison graphs but what they are actually comparing is unclear.
  40. It's not bad
    Joseph#150: Nice cherrypick! From the same (hardly scientific) article: “Since 2000, we’ve lost about 30 percent of the ice area as of 2009, but the thickness of at least the main glacier, the northern ice field, hasn’t changed a great deal. It was 50 meters thick then and now it’s on the order of 45 meters thick,” he said. Lack of long-term data concerning the thickness of the glaciers is what undermined their forecast, Hardy said. “Before 2000, we had no reference for how to treat the thinning other than by looking at historical photographs.”
  41. Mythic Reasoning about Climate Uncertainty
    Well, what do you mean when you say "positivism"? That's only half a joke. I would say that what you call "postmodernism" is actually post-structuralism being used as a defense against moral demands resulting from the dialectic between the current mode of production and human interests: you can't prove my responsibility because proof requires an absolute structure, and all structured theories ultimately fail (sooner rather than later in the case of any theory that involves a human factor). In other words, you attack by pointing out the apparent failure in the approach, and that, I'll assume your opinion, releases you from the knowledge-based responsibility produced by the approach. Yet you offer no alternative, defensible structure. I'll follow Jameson and point out that the term 'postmodern' is typically used to describe the cultural production that results from a historically-specific set of cultural conditions (collectively called 'postmodernity'). Your willingness to use a post-structuralist attack but not offer an alternative is a postmodern response. Models reflect the current-best effort of humans to predict the future of a system that is beyond their ability (individually or collectively) to comprehend. Models may "founder" at the decadal time scale, but if one says they "fail completely," then one implies that one is holding them to a standard that one is incapable of matching (and forever will be). Even models that predict the complete opposite of observed reality end up helping us produce subsequent models that are more accurate. Everyone's a positivist. You yourself continually act based on models with far greater uncertainties than the IPCC, and action is the representation of one's current understanding of "authentic knowledge," an understanding that is in constant flux--again, especially for individuals, but for the social construction of knowledge as well. Any other epistemology is a form of desperate response to the results of the positivist method (a method, by the way, that works increasingly better as the knowledge base is built and as we learn more and more about our weaknesses as humans). There is tremendous hubris in assuming that quantum randomness is either truly random or not random. So whatchu gonna do?
  42. It's not bad
    #149 skywatcher Example of predictions vs current trends disconnect: below is a quote by the scientists who predicted the disappearance of the snows of Kilimanjaro by 2015 “The glaciers are still shrinking, and in the next decades they will almost certainly disappear, but it will probably be on the order of three or four decades, maybe five,” Hardy said recently. “But we don’t know for sure. It might be in only two.” Here is the full article
    Moderator Response: [RH] Hot linked article.
  43. Climate Sensitivity: Feedbacks Anyone?
    I mean that, very unfortunately, it is difficult to quantitatively define the "Earth system sensitivity" to CO2 concentration, since CO2 concentration is an essential internal component of the system and not an external forcing. It is similar to this case: We cannot meaningfully discuss (fast-feedback) sensitivity of the climate system to specific humidity (=water vapor concentration).
  44. Mythic Reasoning about Climate Uncertainty
    trunkmonk#46 "chemistry and eventually everything would be reducable to physics." All science is either physics or stamp collecting. --Ernest Rutherford
  45. Sea level rise is decelerating
    22, Steve Case,
    That you want to complain about it is isn't anything I can do much about.
    No, I'm not "complaining," I am simply pointing out that the period which you selected, whatever your reasons, is hampered by a large number of factors which make it useless to use for an argument one way or the other. You cannot draw any conclusions about sea level rise acceleration using the period and data you have selected. That it shows what you want it to show, and so you are willing to easily overlook these issues, apparently isn't anything I can do much about. Other readers, however, can easily recognize what is being discussed and decide for themselves what the science says, and what can easily be done to promote false conclusions by creating scientific looking but invalid presentations, graphs and whatnot.
  46. Michaels Mischief #2: Opposing Climate Solutions
    I'm not a big fan of electric cars because the sweet spot for their use overlaps public transport. But I suppose Michaels doesn't like that either.
  47. Sea level rise is decelerating
    Steve - we've got a few posts on sea level rise coming up. I agree with you sea level rise in the 'noughties' has tapered off somewhat. But we, no doubt, disagree on what that really means. I'm awaiting on news on publication of a couple of papers on aerosols and subsequent global dimming over the last decade. Both papers shed light on why we have seen a 'slow-down' in global warming in the last decade.
  48. CO2 is just a trace gas
    I was just thinking that Bowdawg @ #26 was using numbers that were a bit too low for my liking. Then it occurred to me to look up how big US gallons are (or should I say, how small they are). British gallons are about 20% bigger than their US cousins (4,546 litres against 3.785 litres) and contain about 3kg of carbon (petrol slightly less, diesel slightly more) & burning one creates 11kg CO2.
  49. Mythic Reasoning about Climate Uncertainty
    Been enjoying the foray into post-modern philosophy on this positivist website. Positivism got a lot of traction in the early twentieth century when quantum mechanics made it seem that chemistry and eventually everything would be reducable to physics.Postmodernism reacted that emergent phenomena in complicated systems made them irreducable, at least in their behavior. We have seen the models founder at the decadal time scale...
  50. Republican Presidential Candidates vs. Climate Science
    EtR, if you're implying that Gore represents a Left position, you're simply wrong. Gore is in no way against capitalism. At best, he's Right-liberal.

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