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Comments 101801 to 101850:

  1. Human CO2 is a tiny % of CO2 emissions
    Yeah, most people here know the glass greenhouse analogy isn't great. But it actually works in this case. To answer your question, kdfv, if you insist on the 10m-thick slabs of glass analogy, think of CO2 as the thin line of caulk that seals up the cracks between those slabs. :-)
  2. Human CO2 is a tiny % of CO2 emissions
    Re: kdfv (79) Greenhouses warm by preventing convection (glass barrier). CO2 and the other non-condensable GHG's work by slowing the loss of radiated energy at the top of the atmosphere (TOA) through back-radiation which warms the lower layers of the atmosphere nearer to the ground and cools the mid-to upper layers of the atmosphere, like the stratosphere and the mesosphere. Hope that helps. The Yooper
  3. Stratospheric Cooling and Tropospheric Warming
    OK, I think I've got a good way to show this, although I've also found some more of my own limitations. I've had a play with the MODTRAN model interface available online: http://geoflop.uchicago.edu/forecast/docs/Projects/modtran.html and tried the following. I used the defaults (tropical, no clouds, zero ground offset temperature. I ran the model with 100ppm CO2, altitude 20km (ie at the tropopause), looking UP (ie at stratospheric emissions coming back) then again with 1000ppm. The results are striking. The increase in emissivity is clearly visible, and total IR from the stratosphere increases from 6.6W/m2 to 11.0W/m2. What I don't understand is that the model produces the same temperature profile at both concs, but this clearly shows that for increased CO2 and constant temperature, IR emission increases, ergo in order to maintain heat balance you'd expect the temperature to reduce. Someone who understands MODTRAN better can probably get the temperature profile to work properly too. Bob - this sort of graphical output, once correct, could be used to very effectively demonstrate the effect of CO2 in the stratosphere, I think. Apologies, my html isn't up to pasting the graphics straight in here.
    Moderator Response: [Daniel Bailey] 1. First type this symbol: < 2. Next, type: img width="500" src="http://image_url/" 3. Replace the URL in Double Quotes "" with the actual URL intended 4. A common error is to have an extra / at the end of the URL; this can be avoided by using the preview function. Should work for you now
  4. Water vapor is the most powerful greenhouse gas
    A few thoughts on the above post... A comparison is made stating that CO2 is an external forcing and water vapour is a result of temperature. This is is misleading, since CO2 levels in the atmosphere can be affected by temperature (for example oceans) while water vapour is added to the atmosphere by power plants and other industry. Therefore are they actually similar in the source for both gases - both affected by temparature and man made sources. The overall point of the article to state that water vapour warming will amplify CO2 warming is misleading, since there is nothing special about the CO2 warming. A natural sun-inducing warming would have similar effects on water vapour. So it is dangerous to state without qualification that 'Water vapour is also the dominant positive feedback in our climate system and amplifies any warming caused by changes in atmospheric CO2. This positive feedback is why climate is so sensitive to CO2 warming.' It could just as easily read 'This postive feedback is why climate is so sensitive to sun warming'. With this in mind, it leads me to ask why such postive feedbacks inherent in the atmosphere have not lead to runway global warming in the past from any naturally induced changes. The reference to Kiehl 1997 shows the clouds also reflect some sunlight back into space (diagram on page 10). Why is this negative feedback not discussed?
    Moderator Response: I fixed your extraneous line breaks. Please use the Preview button before using the Submit button. Clouds are not water vapor; they are condensed water. This post is about water vapor. See the post Positive feedback means runaway warming.
  5. Human CO2 is a tiny % of CO2 emissions
    If the atmospheric water vapour is equal to 10m spread around the world and co2 is equal to 6mm how does the temperature in a greenhouse alter when 10m of glass is increased by 6mm?
  6. Stratospheric Cooling and Tropospheric Warming
    VeryTallGuy @177, I have thought something similar in the past. Your suggestion is not correct, though, because absorptivity increases with emissivity, so that if you double stratospheric CO2, you double the amount of IR from tropospheric CO2 absorbed. You also double the the amount emitted. Obviously, if the stratospheric CO2 is warmer than the tropospheric, doubling both absorption and emmission will result in a larger increase of emission, thus cooling the stratospheric CO2. If the stratospheric CO2 is cooler, doubling both will result in a greater increase in absorption, thus cooling the stratospheric CO2. In the respective cases, the CO2 was warming (cooling) the stratosphere already, and just does so at an increased rate.
  7. The Scientific Guide to Global Warming Skepticism
    [standing ovation for John's work] Already blogged on my site: Doc alert: The Scientific Guide to Global Warming Skepticism
    Response: Thanks Lou, the post is much appreciated (but for the record, I am definitely defatigable).
  8. Stratospheric Cooling and Tropospheric Warming
    Bob @173, you asked for nit-picking so here goes. "The former dominates" Are you sure - I'd like to see a figure put on this to judge it personally. "Energy also causes CO2 molecules to vibrate but although this vibration is related to the energy content of CO2, it is not related to the temperature of the gaseous mixture." If (big if) I have understood correctly, then this isn't quite right. As temperature rises, a larger proportion of CO2 molecules will enter the higher vibrational states and preferentially emit IR in those frequencies. And this is the mechanism by which stratospheric cooling happens - conversion of thermal energy to IR by CO2. So whilst temperature does not measure vibrational energy, increased temperature does cause more CO2 molecules to enter excited states and hence emit IR. (I think)(Tom makes a similar point @176) "IR radiation contains energy and in the absence of matter, this radiation will continue to travel indefinitely. In this situation, there is no temperature because there is no matter." I think this is just confusing - all it amounts to is saying that vacuum has no temperature, and light can travel through it. Can you just cut this para? "These molecules will then collide with other molecules of either N2 or CO2 and some of the K.E. of these particles will be transferred to the CO2 resulting in excited CO2 molecules and a lowered stratospheric temperature. All entities, including atoms and molecules, prefer the unexcited state to the excite state. Therefore, these excited CO2 molecules will emit IR radiation which, in the rarefied stratosphere, will simply be radiated out of the stratosphere. The net result is a lower stratospheric temperature. This does not happen in the troposphere because, due to higher pressures and shorter distances between particles, any emitted radiation gets absorbed by another nearby CO2 molecule." A suggestion to simplify: "Due to the lower density of the stratosphere, IR is less likely to be reabsorbed, and more likely to escape either to space or back to the troposphere. With increased CO2 concentration, IR emission increases in the part of the spectrum where CO2 dominates. Thermal emissions in the rest of the spectrum must reduce to maintain overall equilibrium, which results in a lower temperature to maintain the heat balance." Tom Curtis @176 "where it not for Ozone being a net absorber of energy in the stratosphere, CO2 would not be a net emitter of energy in the stratosphere. And it is only by being a net emitter that CO2 can cool." I think this may be incorrect. I think that CO2 will increase the emissivity of the stratosphere regardless of ozone and therefore decrease the temperature. However, without Ozone, the temperature of the stratosphere would be much lower, as the UV energy absorbed by Ozone would then be transmitted. The relative effect of extra CO2 would, though, I think reduce the temperature still further. And I'd just like to emphasise I'm no expert in this and could be very much mistaken in my analysis. Interesting to try and understand though.
  9. The Scientific Guide to Global Warming Skepticism
    Brilliant!
  10. We're heading into an ice age
    NQoA wrote: "if accumulated CO2 is causing the globe to warm, then - by the AWG logic - 2008 through 2010 would be below 2007." That's not any 'AGW logic' I've ever heard of. First, sea ice extent is a measure of ice area and how spread out the ice is. The 2007 value was noted at the time to have been in part caused by wind conditions causing the ice to mass up in a small area (which 'skeptics' took as an excuse to ignore it). Now we've had three subsequent years where we haven't seen winds pack the ice into such a small area but the extent has been nearly as low in two of them, because there is now less ice... as we can see from looking at ice volume values, which have continued to drop each year since 2007. Second, there is something called weather which can cause large fluctuations in all kinds of climate readings. The Arctic winds contributing to the low extent in 2007 are one example. In this case the volume (aka 'actual amount') of Arctic sea ice has declined each of the past few years... but if it were to tick up for a few years that wouldn't be contrary to AGW in any way. Just expected natural variation.
  11. The human fingerprint in the seasons
    Norman, as I said somewhere further up in this thread... it is true that various climate feedbacks would take place regardless of what the forcing was. However, it is not true that the feedbacks would be exactly the same. For instance, your claims about water vapor and polar albedo (aka Arctic amplification) feedbacks are demonstrably incorrect. When atmospheric CO2 levels increase they do so globally. The CO2 level goes up for the entire planet and thus the rate of infrared radiation escape goes down. Further, this is a year round phenomenon... the CO2 level only fluctuates slightly during the year, much less than the cumulative increase we have observed (indeed, the annual rate of increase is now about equal in magnitude to the annual fluctuation). As such it causes increased water vapor and increased surface warming worldwide and year round... obviously with large fluctuations for weather events. A solar forcing on the other hand would be geographically and seasonally localized. If it were exactly equal in total magnitude to a CO2 forcing most of that energy would be located in the tropics and during Summer. Thus, while Arctic amplification would still occur it would be much less pronounced because a much smaller proportion of the forcing is at work in the Arctic. Ditto water vapor. It would increase more in the tropics, but less for the rest of the world... resulting in an even more pronounced tropical warming signal over that of the Arctic. Likewise we wouldn't see the accelerated Winter warming that we have with CO2 because a solar forcing would be concentrated in the Summer months. Feedbacks can only respond to forcings when and where they occur. This is inescapable. Thus, you can't have a strong Winter feedback from a Summer forcing... nor a strong Arctic feedback from a tropical forcing.
  12. How to explain Milankovitch cycles to a hostile Congressman in 30 seconds
    jg - that is a superb piece of work, it's bookmarked for future use! I saw the Alley testimony a few weeks ago, and was disturbed by the dreadful way the Republican ignored his answers and kept repeating the most tired old talking points. I agree with archiesteel that Alley should have straightforwardly called out the Mars canard, but I guess he's caught in a hard place where he has to be polite and reasonable with his answers, yet the questioner does not have to be polite (and ignored/spoke over the answers when the got near being utterly inconvenient truths). But the more opportunity that Richard Alley gets to communicate, then the better for all of us, he is fantastic at getting the science across. Alley's CO2 control knob AGU talk should be standard learning material.
  13. The Scientific Guide to Global Warming Skepticism
    Thunderbirds Are Go Push it out there people. G
  14. The Scientific Guide to Global Warming Skepticism
    Absolutely fantastic. Certainly a lot of work but absolutely fantastic. Bob
    Response: Bob, if we do an extended version, we will of course have to explain why greenhouse warming causes the stratosphere to cool. Fortunately you've softened that subject up for us :-)
  15. The human fingerprint in the seasons
    #146 Albatross, "That all said, I have no idea what your speaking to polar amplification of the Arctic has to do with the original post..." The conclusion of the original post "Solar warming should result in the tropics warming faster than the poles. What we observe instead is the poles warming around 3 times faster than the equator. All these pieces of evidence paint a consistent picture - greenhouse gases, not the sun, are driving global warming." The article on polar amplification suggests that warm poles relative to tropics does not appear related to either GHG or solar forcing. It is a unique phenomena based upon another climate factor.
  16. Eric (skeptic) at 21:52 PM on 8 December 2010
    It's cosmic rays
    #25 muoncounter, thanks for transferring my comment to a more appropriate thread. As I tried to explain in the other thread, I am not "chasing" anything, only mentioning a few of the causes of variations in sensitivity that are not in any paleo studies or current era models. Dana shows the non-match to 30 years of temperature in his threads and John shows recent non-match above as well. So the CO2 warming theory holds well for 30 years of precise GCR data and warming data. GCR is a much more variable effect both with clouds as above, and SSW http://www.appmath.columbia.edu/ssws/index.php and other effects. Those effects come and go and may balance out over time. They won't explain any inexorable monotonic warming or cooling because of their measured variability and because their effects are nonlinear and indirect through cloud and weather pattern changes. Events like SSW are modulated by solar activity but celestial in origin so their source is unpredictable but their intensity will be more or less diminished by higher solar activity. The most interesting aspect is the effect on climate sensitivity, not direct warming or cooling. A blocking event such as created by SSW or by other mechanisms will tend to diminish the water vapor feedback part of sensitivity. Another aligned effect is what Mizimi mentions in #10 above, that the water vapor feedback is diminished by CGR cloud formation. It is not an energy effect as correctly pointed out in #12, but it is an important change in sensitivity. A long term change in solar activity and thus GCR flux is a very important consideration in potential paleo and model analysis. Part of the higher sensitivity to CO2 warming measured in the late 20th century may be due to solar activity which diminished both the intensity of SSW events and the low clouds from GCR. Likewise part of the recent decrease in sensitivity may be be explained with solar activity decreases. This last paragraph is speculative, and I welcome critiques and counter evidence.
  17. We're heading into an ice age
    NQoA @162, it is very easy to look up Doran's paper and see that it was 75 of 77 climatologists actively publishing in climatology that answered yes. So that would be 97.4% of that restricted sample. Or are you, perhaps trying to suggest it was only 75 out of the surveyed climatolotists that answered yes? That is certainly what you asserted, but it is false. In fact, of around 157 climatologists surveyed, around 138, or 88% answered yes to that question. Further, 2580 of all respondants (82%) answered yes to question 2. Even if we inflate the figures from the Oregon petition to allow for the effect of responce rates, we still have 97% of scientist who actually know the science of climate change support the basic veracity of the IPCC reports, while apparently, around 0.3% are very ill informed.
  18. The Scientific Guide to Global Warming Skepticism
    A really clear document. I assumne there's no restrictions ( apart from correctly attributing the material) if I print off and give away a few copies
    Response: The Guide has a Creative Commons licence (see the second page of the PDF) so you're welcome to copy the material and distribute.
  19. It's the sun
    Norman @746, you ought to read your sources more carefully. Specifically, from your link above,
    "If you look at the total atmospheric column, from your head on up to the top of the atmosphere, this solar proton event depleted less than one percent of the total ozone in the Northern Hemisphere."
    A 1% reduction of NH ozone (less from the SH) would represent at most a 1% reduction of incoming UV energy, and a 0.25% reduction in temperature. To put that into perspective, chlorofluorocarbons reduced stratospheric ozone by about 30%, an effect which contributes around 30% of the observed cooling of the stratosphere. As the event causing this reduction was episodic (the one observed being the third largest in 30 years) and as the Ozone recovers between episodes, it is doubtfull that such events would compensate for the warming effect in the stratosphere of increased insolation. They certainly would not reverse that effect and give as large a cooling as has been observed.
  20. The human fingerprint in the seasons
    TOP, You hit my nonsense meter with this one, "...because the ocean re-radiates almost nil energy via radiation." Wrong. Please look up the definition of black body and Stefan-Boltzmann. Sea water is a reasonably good approximation of a black body; therefore it radiates energy quite well.
  21. We're heading into an ice age
    NQoA Do you mean that you think that global warming means that every year should show a progressive increase or decrease in each indicator? And that any indicator not showing such a response in any year shows that the globe is not warming?
  22. Renewable Baseload Energy
    380 swieder Load following or spinning reserve capabilities of nuclear do not seem to attract a lot of public attention. Most likely because it's not an issue in many grids where nuclear is 20%-30% or less. As I am not a nuclear engineer, I can only go on what I read from credible sources. It seems to me that if there is an issue with material fatigue or deformation, it's severity or lack of severity is likely to be dependent on specific reactor designs. There is continuous research into the materials science of the hostile environment of reactor cores so I would be a bit surprised if this problem, if it really exists, has not been solved or cannot be solved. I note that Areva state that their current reactor designs load follow at constant temperature which is important not only to the core, but piping, heat exchangers, turbines and such like. Can Nuclear Power Be Flexible? discusses some of the engineering and economic issues. I think this could be an important issue in the future in the context of grid integration with wind. You may be able to get a more substantive answer by posting a question on bravenewclimate.com or a couple of the other nuclear blogs. I quite agree that external costs should be factored in, and also agree that CCS is probably a bit of a dud. Estimates of the external costs of various generation technologies including nuclear are provided here: EU External Costs for Electricity and Transport
  23. Renewable Baseload Energy
    379 Archiesteel 1. I posted both IEA and DOE/EIA estimates of LCOE for nuclear which are at least comparable to and probably lower than wind (the cheapest renewable). Nuclear is undoubtedly cheaper in east and south Asia. Impossible to overstate the importance of this. But it doesn't end there - nuclear displaces coal directly because it is baseload and dispatchable. This makes nuke generated electricity more valuable than wind generation both from an economic and emissions reduction standpoint. 2. Distributed power generation by consumers-producers on a scale and time frame to make a serious impact on emissions is a fantasy. Not only do PV panels need to drop in price a lot, but storage needs to drop in price by a lot. Installation and maintenance costs are not likely to go down. There is a reason things are done on an industrial scale - it's cheaper. I had a glance at the German PV performance for December. It's shockingly poor. Germany has about 15GW of nominal PV capacity. The maximum output at any time of the day on the best day was 0.7GW. On the worst day just 0.2GW. The capacity factor must be somewhere between 1% and 2%. Now think about storage requirements. Most of the world are not loopy survivalists living in the Arizona desert and are not interested in paying for that sort of lifestyle. I challenge anybody who thinks micro generation will make a serious dent into emissions to present a decently constructed scenario where say 3% of the worlds electricity could be feasibly produced by this mean by 2020. 3. It is quite wrong to assume that R&D funding will solve all engineering problems. Why is battery technology progress so painfully slow? Because you can only store so much energy in chemical bonds - the same reason so much fossil fuel is burned for energy. Progress will come but there are underlying hard physical limitations. Same is true for solar and wind - the energy density is low and this will ultimately place a bottom line under the cost for wind and solar CSP. Same is also true for mechanical energy storage such as compressed air, flywheels etc. Nuclear IS different because the binding energy of the nucleus is huge in comparison. No question that some serious engineering is required to realize the potential - but the potential is there, and there is a huge gulf between current implementation and physical limits. 4.There are multiple reasons for the back and forth, but the main reason is ultimately the agitation for the banning of nuclear power and/or the efforts to be as obstructionist as possible where new nuclear is proposed or being built. In my book this is the height of irresponsibility towards climate. There is also a lot of nonsense willfully spread. In discussion of climate science, nonsense is jumped on rapidly from a great hight and rightly so. In discussion of energy, it seems that just about anything goes. Not good enough. 5. My future projection. Sometime towards the end of this decade, when it becomes obvious that non-hydro renewables are not cutting it, there will be a rush to nuclear for reasons of low emissions and energy security. Asian nations will be the biggest suppliers together with Russia and France. And yes I do get involved in discussions other than nuclear. I've had far too many brawls with climate deniers - but not here. While confronting the deniers is important, clarity about energy is just as, or perhaps more important. There are of course ideologically motivated tea party type kooks who will never be persuaded, but there are a significant number of climate deniers that can be made to change their tune if they are convinced that there is road to a low emissions future that is not energy poor.
  24. Renewable Baseload Energy
    @quokka # 378 I had the impression you could technially elude a bit on the fact of the cycle limitation of NPP - is this something discussed seriously in pro-N circles? And if load follow operation is not something regular for NPP (e.g. limited to cycle number of 1000 or such), it is not valid to use it as an argument for nucelar. Regarding the cost: i fully agree with you tht the cheapest source is preferably, but i dont agree that this points to coal/nuclear or oil: considering all externalized cost for detremental effects of (coal, oil, nucler for) mining, transport, enrichment, storage, pollution during production etc. I strongly believe that todays energy is simply to cheap and that those "expensive" renewable can match them in case these cost are considered. Societies worldwide are paying for these external cost every single day. One important point in my mind regarding cost speaks for renewable in any case: the cost for electricity (power) will rise anyway, with or without one-time large investments for renewable now. But the cost for renewable will always only get less due to maturity, they will not increase. No cost decrease for coal, oil, nuclear are expected as far as i know, it will only get more costly with CCS or better environmental standards or safety standards.
  25. NQuestofApollo at 18:30 PM on 8 December 2010
    We're heading into an ice age
    Muoncounter (132): If "Artic sea ice falls to third-lowest extent", that means there were at least two extents that were greater. Here is the chart from the link that you sent - please notice that 2007 is the lowest point and 2008 - 2010 show a greater sea ice extent. While I stand corrected on one point: the increase has been for only two of the last three years; the main point remains: if accumulated CO2 is causing the globe to warm, then - by the AWG logic - 2008 through 2010 would be below 2007.
  26. NQuestofApollo at 18:29 PM on 8 December 2010
    We're heading into an ice age
    To Rob (127) - I have to ask: did you even read Doran's 2009 document? Exactly 75 climatologist agreed - NOT with your Orwellian claim that climate scientists believe that "climate change is real", what fool ever said it isn't? - but, that "human activity is a significant contributing factor in changing mean global temperatures". (do you understand the distinction?) Since you are the master of percentages, just what percentage of ALL climatologist would this be?
  27. NQuestofApollo at 18:29 PM on 8 December 2010
    We're heading into an ice age
    My second main point was questioning whether CO2 leads or follows global warming. To this point, Rob and Daniel were direct: CO2 leads global warming because it's basic physics. Okay - lets talk "physics". Anthropogenic CO2 emissions are about 30 Gtons per year . Total CO2 emissions are about 250 Gtons per year (for this, I estimated a consistent 2% per year increase) - making man responsible for about 12% of all CO2 emissions world wide (this includes CO2 sink effects). The impact CO2 has on GHE is, at its upper limit, about 26%. That means that anthropogenic CO2 emissions - WORLD WIDE - have, at most, a 3.12% impact on the green house effect. And for that, I should be hysterical? The problem here is that the most influential GHG is water vapor (since you all seem to trust the IPCC implicitly, please see their First Assessment Report by Working Group I). By the logic of suppressing GHGs, should we stop cooking and boiling water? Sound ridiculous? That is how I feel about CO2 emissions causing globe disasters. I've stated my reasons. I've tried to give reasonable supporting documents to the reasons for my doubts about AGW. We may have to just agree to disagree.
    Moderator Response: The point about human CO2 emissions being a small percentage of the total is addressed here.
    The point about CO2 lagging temperature is addressed here.
    The point about water vapor being the most dominant GHG is addressed here.

    In the future, please review the List of Skeptic Arguments before posting and place your individual arguments in the appropriate thread (ideally after reading what the post has to say). This will ensure that your points will be readily available to anyone reviewing the discussion of the relevant subject.

    Per the comment policy of this site, any future off-topic posts will be deleted.
  28. NQuestofApollo at 18:26 PM on 8 December 2010
    We're heading into an ice age
    Regarding lines 127-136 (sorry for the delayed response - life got in the way) To JMurphy in particular, I appreciate the time you spent providing all of those links. And, I have to apologize, as it appears that I may have been unclear in the main points of my previous post. My points were only: 1. to questioning the quality of the scientists and 2. questioning CO2 impact on temperature Your links to the hockey stick issue don't change the fact that two different sets of data were concatenated. AGW promoters find this acceptable, the rest of us do not. I'd like to discuss the urban heat effect, but fear we would just talk past each other. Daniel stated that GHG effect of CO2 is "not seriously questioned by any competent scientist anywhere". The only purpose in sending the link to the Petition Project was to show that over 31,000 scientists - surely some of whom must be "competent scientist" somewhere - provided a detailed explanation for their disagreement with AGW. I also took issue with his definition of "competent scientist" and provided links to support my position. It wasn't my intention to open a direct discussion on the petition project or climategate, but to offer those issues as causing legitimate doubt. JMurphy - most of your links regarding the IPCC back up what I said - the IPCC either lied or "misread" data. Furthermore, that happened because their reports were NOT peer viewed. Further promoting my point that they are not an entirely reliable source. That IPCC link represents meager 831 scientists. Additionally, my concerns remain about the quality of the scientists behind the IPCC. The IPCC states that their procedures provide for the InterAcademy Council to "assemble an international panel of experts". Now, you may trust that their basis of selection is unbiased and only considers the credentials of those selected, but I do not. Item 7 of this report gives me pause for concern on that topic as well.
  29. Stratospheric Cooling and Tropospheric Warming
    Bob, I have two points, and I will start with your second explanation first. Below is an image of the outgoing emmissions spectra over the Sahara, the Mediterainian, and over Antarctica: You will notice the small spike at the center of the CO2 absorption/emmision pattern in each case. That spike represents emissions by stratospheric CO2, which being warmer than stropospheric CO2, has a higher brightness temperature. The important point to notice is that the spike is confined to the center of the CO2 absorption/emmision band. Looking at your figure 2 brought my attention to the fact that the majority of excess absorption in the troposphere with increased CO2 takes place on the wings of the band, not at the center. It appears from your figure 2 that there is no reduction in CO2 absorption at the center of the band. But because it is at the center of the band where stratospheric CO2 emits and absorbs, it follows that the reduction in IR on the wings of the band will have no tendency to cool the stratosphere. Clearly, in the non-equilibrium state, adding extra CO2 will reduce the brightness temperature at the center of the CO2 band as well as at the wings, and will consequently reduce stratospheric temperatures. But as the troposphere achieves radiative equilibrium, it may be that the loss of IR radiation on the wings of the band undercompensates for, exactly compensates for, or over compensates for the increased emmisions outside that band due to increased surface temperature. In the first case, the equilibrium brightness temperature at the center of the CO2 band will be less than it was before introducing more CO2, thus cooling the stratosphere. In the second, it will have no effect; and in the third it will slightly warm the stratosphere. As to which case will actually apply, you will have to ask an expert; and it may be the models insufficiently clarify the situation. For practical purposes though, it appears that the cooling of the stratosphere due to the second method is a temporary effect, which declines to close to zero as the atmosphere achieves radiative equilibrium. (As an aside,the emission spectrum for Antarctica is especially interesting; showing, as it does, that the tropospheric CO2 was warmer than the surface. In the situation at the time of this observation, the effect of CO2 in the atmosphere would have been to cool the surface of Antarctica, rather than to warm it. ;) ) On to the first method: Where you say, "... this vibration is related to the energy content of CO2, it is not related to the temperature of the gaseous mixture", this is not strictly correct. The energy stored as vibration is not measured by the temperature, but there is an equilibrium relationship between the heat stored as molecular vibrations and the temperature of the gass. The actual relationship varies from gas to gas, and depends of the degrees of freedom of their vibrational modes. Because the relationship between heat stored as vibration, and heat stored as translation energy, adding more CO2 at the same temperature will not cool a gass (ignoring considerations of pressure and volume), for the added CO2 will have the same proportion of energy stored as internal vibrations. Adding a cooler or warmer amount of CO2 will, of course, temporarilly cool or warm the stratosphere, but the stratosphere will quickly return to equilibrium. What is happening in any gass is that the energy stored as vibration interacts with, and seeks to achieve equilibrium with two sources of energy. The first is the energy from collisions within the gass, which is a function of temperature. The second is the radiant energy it emits (which is a function of its temperature) and recieves (which is a function of the temperature of the source of the radiation it captures). If the temperature of the gas is less than the temperature of source of its radiant energy, its the energy it radiates will be less than that which it recieves, increasing its vibrational energy. This excess will then be passed onto the ambient gass, increasing its temperature. If the radiant energy it recieves has a lower "temperature" than the ambient gass, its will emit more energy than it recieves, draining its pool of vibrational energy. This shortfall will then be made up by collisions with other gass molecules, cooling the ambient gass. Applying this to your model, and assuming all energy transfers are radiant, the effect is that the stratospheric gass will reach an equilibrium temperature equal to the brigtness temperature of the tropospheric CO2. If the stratosphere were cooler than that, than the stratospheric CO2 would be a net absorber of radiant energy, thus warming the stratosphere. If it were warmer, the CO2 would be a net emitter, thus cooling the stratosphere. (In reality, the temperature would be determined by convection and the adiabatic lapse rate, which would dominate at stratospheric altitudes were it not for a major source of radiant energy to those levels.) So, once again, I come back to Ozone. where it not for Ozone being a net absorber of energy in the stratosphere, CO2 would not be a net emitter of energy in the stratosphere. And it is only by being a net emitter that CO2 can cool.
  30. The human fingerprint in the seasons
    Norman @141, Regarding warming rates for polar amplification. You need to keep a couple of factors in mind regarding the the paper by Chylek et al. (2009) that you cited. They, understandably, have access to a few, widely separated stations, and they have consequently greatly underestimated the rate of warming north of 70 N after 1980, especially during the winter months. Using ECMWF-interim data, Screen and Simmonds (2010) found warming of 1.9 C/decade in DJF for areas north of 70 N between 1989 and 2008, compared to 0.58 C/decade for the same area area and season (from 1980-2008) in Chylek et al. (2009). That is a huge difference. We are now clearly dealing with a very different beast than was the case back in the 1910-1940 window. Interestingly, the rate of warming during the winter determined by Chylek et al, for areas north of 70 N was 1.63 C between 1910-1940-- that value is very similar to the rate of warming obtained by Screen and Simmonds for the same season. One has to wonder why Chylek et al's analysis grossly underestimates the post 1980 warming-- did they perhaps use different stations for the two periods? Something does not add up. Also note that, according to Chylek, the rate of warming for the globe (from NASA GISTEMP data) between 1980 and 2008 was almost double (~0.20 C/decade) that observed between 1910 and 1940 (~0.10 C/decade), despite a slight decrease in insolation during after 1980. So Monckton should now be convinced that AGW is real (referring to his entertaining conversation with a Guardian reporter at Cancun)....but I digress. Be careful of confusing regional regimes and internal climate modes with drivers of global climate. That all said, I have no idea what your speaking to polar amplification of the Arctic has to do with the original post...
  31. The Scientific Guide to Global Warming Skepticism
    It's Christmas come early! Thanks, John!
  32. The human fingerprint in the seasons
    Re: Norman You have me torn, sir. On one hand, I dearly wish to aid you in strengthening your understanding of climate science. On the other hand, I believe your gaining an actual understanding is not something I can help you with. By no means am I implying, sir, that you are here under false pretense. But the overwhelming straw-grasping makes it difficult to even know where to begin to help you. Time and again others more knowledgable than I have picked you up, dusted you off and pointed you in the right direction. And to have you come back here and say, "Yes, but _________" (anything but what you were told). The more I have tried to help the less positive effect I seem to engender. So I will recuse myself and bid you adieu. And apologize for being the poor clay vessel I am. The Yooper
  33. The Scientific Guide to Global Warming Skepticism
    Incredible work John! Congratulations, this is a professional document that is crammed with important and pertinent information. Consequently, it is going to be a great resource for lay people wanting to learn more about climate science and anthropogenic climate change (climate disruption). Again, a job well done and thanks to all those experts who offered their valuable time and expertise. And most of all, a sincere thanks to John Cook-- he is a true champion of science and the epitome of pedagogy. PS: Is there anyway people will be able to view the document's content on their iPhones?
    Response: The Guide is essentially a compilation of content from the various rebuttals and blog posts throughout the Skeptical Science website, simplifying the text to make it more accessible to the average person, then showed to a number of scientists to ensure all the science is accurately portrayed. So generally speaking, most of the content from the Guide can be found in the iPhone app.

    Sorry, that's the best I can do at the moment :-)
  34. It's the sun
    #743 Daniel Bailey, Ray Ladbury may make statements with vigor and certainty but that does not make them correct. "First, you have to look at ALL the evidence. There is no way you get simultaneous stratospheric cooling and tropospheric warming without a greenhouse forcing. And increased tropospheric water vapor ain’t gonna give you that." NASA may disagree. An active Sun can destroy ozone in the stratosphere (the primary cause of warming in that region). An active sun can warm the Troposphere by adding more heat to the surface and by destroying the ozone it can at the same time cool the stratosphere. No greenhouse forcing is needed in this case. You have two possible causes for an observed effect. It is possible (I am not saying it is likely, just questioning the claim made by Ray Ladbury) that the troposphere can warm at the same time the stratosphere cools via active sun without GHG forcing (in an atmophere with no GHG that is). Supporting evidence for the above claim. Active Sun can destroy ozone in stratosphere.
  35. The human fingerprint in the seasons
    Norman #143 Well I've examined the relationship between CO2 and warming myself using the publicly available data (here), and my conclusion based on this data, and the theoretical evidence from physics, chemistry and to a lesser extent meterology, is that for the current situation not to be driven by CO2 would be a coincidence of fairly staggering proportions.
  36. The human fingerprint in the seasons
    #142 kdkd "Also, the solar hypothesis suggests that the early increases in temperature will be most measurable during day time, but that in fact we observe night time warming is most marked." I do have a possilbe explanation for this one that does not require CO2 but can be explained by a more active sun. I will link to the page and pull out a factoid from it. Properties of moist air. Quote from this page: "Notice that water vapour, once generated, also requires more heat than dry air to raise its temperature further: 1.84 kJ/kg.C against about 1 kJ/kg.C for dry air." If the Earth received more energy (via less clouds and lower albedo) that energy would evaporate more water on land and sea (exception of desert climate). Warming this increased moist air takes more energy so the daytime does not warm as much relative to the night. Now what happens at night? This moist air is holding more energy than drier air and it cools off slower keeping the night warmer relative to less moist nights. Again I am not saying my point is valid or correct. Just challenging the three fingerprints of AGW, I don't think it is as clearly obvious as the Author makes it out to be.
  37. The Scientific Guide to Global Warming Skepticism
    Great Work Everyone and in Particular John! Thanks for all the time you've put in John!
    Response: I forgot to mention in the post that a big word of thanks is owed to the many scientists and Skeptical Science contributors who scrutinised the Guide and offered comments. In particular, the Skeptical Science authors nitpicked and critiqued with an enthusiasm that would make any skeptic proud!
  38. The human fingerprint in the seasons
    Norman #141 There are are a couple of mid-80s and/or early 90s environmental science text books on my bookshelves, and from memory, they showed that the output of climate models predicted precocious arctic warming under a CO2 forcing scenario, but either absent or not as strong where something other than greenhouse gasses were the driver of climate. Also, the solar hypothesis suggests that the early increases in temperature will be most measurable during day time, but that in fact we observe night time warming is most marked.
  39. A Cloudy Outlook for Low Climate Sensitivity
    Re: jasonk (106) Global warming won't stop because people in general in the US (or anywhere else, for that matter) don't currently place a high priority on it. They longer they wait, the worse it will get. And the less that can be done about it. More's the pity. Meanwhile, we vocal few here still try to talk about the science, not electrical flights of fancy or iris effect pixie dust. It's what we've decided to do with the time we have. While the time to make a difference still has not completely elapsed. The Yooper
  40. The human fingerprint in the seasons
    muoncounter, This claim "Solar warming should result in the tropics warming faster than the poles. What we observe instead is the poles warming around 3 times faster than the equator. All these pieces of evidence paint a consistent picture - greenhouse gases, not the sun, are driving global warming." Has a flaw in the reasoning. I linked to this article on a previous thread but a very important point should not be missed. I will post a quote and then a hyperlink to the article. "Understanding Arctic temperature variability is essential for assessing possible future melting of the Greenland ice sheet, Arctic sea ice and Arctic permafrost. Temperature trend reversals in 1940 and 1970 separate two Arctic warming periods (1910–1940 and 1970–2008) by a significant 1940– 1970 cooling period. Analyzing temperature records of the Arctic meteorological stations we find that (a) the Arctic amplification (ratio of the Arctic to global temperature trends) is not a constant but varies in time on a multi-decadal time scale, (b) the Arctic warming from 1910–1940 proceeded at a significantly faster rate than the current 1970–2008 warming, and (c) the Arctic temperature changes are highly correlated with the Atlantic Multi-decadal Oscillation (AMO) suggesting the Atlantic Ocean thermohaline circulation is linked to the Arctic temperature variability on a multi-decadal time scale." Of significance "the Arctic warming from 1910–1940 proceeded at a significantly faster rate than the current 1970–2008 warming." From what I have read, CO2 levels were much lower in 1910 as compared to today. Yet the Arctic had a higher amplification than current, this would be very strong evidence that the greater warming at the poles is not due to atmospheric carbon dioxide levels but some other unrelated phenomena. Here is a link to the article. Peer-reviewed and accepted.
  41. The human fingerprint in the seasons
    #137 Daniel Bailey "So you're saying it was cloudier before 1980...doesn't parse." Not me saying it, the available data suggests it is a strong possibility. On this web site they warn the data may not be accurate but never-the-less, the chart shows low cloud cover decreasing (low clouds are thought to cause cooling overall). Cloud cover main page. Three different graphs show cloud cover has decreased since 1980. #138 muoncounter "I suppose we could also throw in a few dozen other unknown 'factors' if you like. But let's get back to the topic of this thread and the 'fingerprint' question. Cloud theories, electrical currents, little green men, don't produce the observed seasonal warming differentials" And why can't they? If the tropics are cloudier overall and the poles relatively less cloudy than before that would create the observed temperature difference between tropics and poles. It would appear. The statement that man-made forcing accounts for nearly all the observed temperature change is based upon an assumption for climate sensitivity, it is circular reasoning from what I have read. The current warming is attributed mostly to CO2 because they do not have another valid explanation for the warming so that is how the climate sensitivity was determined. I think a really good study of cloud cover is needed to ensure that this is not what is responsible for a majority of heating or cooling that has taken place in the last 100 years. So far none exists. The current satellite cloud cover study is not known to be accurate. At least answer one question. How can you be certain a considerable amount of the warming that took place was not from low cloud reduction? What is the basis of your answer to this question? #139 kdkd Have you played with the albedo calculator? A 1% change in albedo will change global temp by 1 F. Are you sure your analysis is sufficient to make your conclusion?
  42. CO2 lags temperature
    CO2 is a very SLOW feedback from temperature increase. I dont think any AR4 model include it as a feedback. Actually we do know the mass of CO2 in the air, and yes, nearly half of our emissions are being mopped up - but half arent. However, what happens when the sinks are saturated? What makes you think photosynthesis is dominant over oceans as a CO2 sink? Have you done the maths and if so how does it compare with result of others eg here or here
  43. Renewable Baseload Energy
    @quokka: as other posters have pointed, Nuclear isn't as cheap as you claim it to be, and it does not allow for largely distributed power generation by consumers-producers. It is not the perfect energy solution, as no single energy source is. What we need is a mix of energy production methods, and renewables have a place in this mix. Furthermore, as current technological developments in PVs show, prices are bound to come down through technical advances and production volume. After all, if Solar and Wind had had as much money poured into them as Nuclear has over the last 60 years, our energy problems would likely be non-existent today. You've stated your case quite well, but since in my view you have failed to challenge the argument put forth in this article, I guess we'll simply have to agree to disagree. Your advocacy skills are wasted here, and will continue to be as long as you appear so one-sided towards this single issue. I mean, I haven't read many of your other posts here, but do you ever get involved in any discussion that doesn't degenerate into an endless back-and-forth about whether nuclear power is the only solution or not? I appreciate the fact you believe climate change is real, and that CO2 is responsible. But really, this talk about how nuclear will save the day is tiresome, and frankly sounds more and more like a bunch of nuclear industry talking points...
  44. CO2 lags temperature
    @cgp: "I don't buy this theory." I do, as do most people who understand science. You see, the theory has a lot of evidence supporting it. I have yet to see any evidence for your claims. I second muoncounter's suggestion: learn more of the actual science before making such unsupported claims.
  45. A Cloudy Outlook for Low Climate Sensitivity
    global warming was last on the list of early 2010 priorities. now still deeper into the recession with still super high unemployment, hostile north korea, nuclear capable iran, extremely sensitive confidential us documents leaked...i suspect that global warming importance has slipped to number 32,966 on a list of top 100. i commend this website for it's continued passion for keeping global warming alive. though it may seem like a losing battle...it is the vocal minority that actually elicit change...whether for good or for bad.
  46. It's the sun
    Ned, I had kind of (lost interest really in someone determined not to understand physics) so perhaps "noone" was optimistic. Let try "no physicist doubts..."
  47. A Cloudy Outlook for Low Climate Sensitivity
    #102: "we're currently on pace to double atmospheric CO2 levels in the next 75 years or so. That's doubled from current levels," Dana, even at 3ppm per year, 75 years is 'only' another 225 ppm. I'm sure we'll hit 390 this spring, but it'll take a while longer to double than 75 years. Besides, I'm thinking by 450ppm, things will get downright ugly.
  48. CO2 lags temperature
    #214: "... co2 greenhouse effect sufficient to influence temperature." Try to substantiate your claims, rather than just make such declarations. You might want to do some reading before you engage in so many blanket dismissals. Start here, here and here, then we can talk.
  49. CO2 lags temperature
    I don't buy this theory. External event rises temperature. Soils and vegetation release co2 in a global burnoff. Probably the ocean mass heat memory with dissolution is the likely explanation of the centuries delay. If co2 amplified minor temp rises then it should be in synch without delays of centuries. Eventually the temperature goes down and the plants etc can reabsorb the gas back to photosynthesis equilibrium levels. You never get the amplification process because photosynthesis is such a dominant process. Perhaps when the conc goes above 1 per cent is co2 greenhouse effect sufficient to influence temperature. Look if co2's lifetime was several centuries then do the calculation of 100 years of fossil consumption with 5gt per year for the last 20 years. What should the co2 concentration be? I don't know the mass of co2 in the air currently, but some have done it and say that half the mass is missing, ie perhaps a 20 year lifetime, some say 5. This stuff is scrubbed from the air.
  50. Stratospheric Cooling and Tropospheric Warming
    Joe Blog - 174 We discussed the big issues and only nitpicking is left. I want nitpicking and your wording is much better than mine was. Thank you. I want very much to get a pro. I corresonded with Rasmus Benestad who is one of the pros on Real Climate. He said he hadn't thought about all of this since graduate school but gave me some ideas including the need to combine those graphs. He also recommend two scientists from Real Climate to send it to. So I'm not going to just send a new email. I'm going to forward his mail to me recommending the scientist. That will pretty much force him to critique it. I combined the graphs by painting pixel by pixel. Laborious is a word that comes to mind. John is going to do some artwork for me. Something to clarify the first process. Thanks again. Bob Bob

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