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Comments 123801 to 123850:

123801. David Horton at 19:12 PM on 22 February 2010
        Have American Thinker disproven global warming?
        Think the first word in your title should be Has, not Have, John, but more to the point - the statistical technique of "eye-balling graphs" is such a common feature of denier science that we could begin calling them "Eyeballers".
123802. Doug Bostrom at 18:59 PM on 22 February 2010
        Have American Thinker disproven global warming?
        "Therefore, the AGW hypothesis is disproven." If only it were that simple.
123803. Riccardo at 17:58 PM on 22 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        What Berényi Péter did is a sort of smoothing under the assumption of linearity of the 20 years period. This assumption is clearly not supported overall by the data and so his smothing procedure is flawed. Why not use standard smoothing filters?
123804. Bern at 17:20 PM on 22 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Occam's Razor would suggest that BP has made an error. I think more detail is required on exactly what calculations have produced that 0.6ºC/century cooling rate, so that others can check it, as such a result is contrary to considerable other evidence & scientific publications. Extraordinary claims require extraordinary proof, as Carl Sagan once said.
123805. PeterWinters at 15:22 PM on 22 February 2010
        Did Phil Jones really say global warming ended in 1995?
        There seems to be a number of mistakes journalists make in reporting on this issue. 1. Understanding that 'no statistical difference' can reflect on either the data available or the underlying phenomena ... and Phil Jones made it clear that it is due to the limited amount of data available. 2. Understanding that science is never 'settled', it is always conditional (as Mike Hulme is particularly keen to argue). 3. Having a good appreciation of what constitutes good evidence for / against climate change. 4. Understanding the way major scientific debates are conducted & the strong emotions it can evoke (e.g. as Darwin's ideas did in the 1860s) In Canada, the journalist, Margaret Wente makes a number of these mistakes (IMHO) in this article in the Globe and Mail http://www.theglobeandmail.com/news/opinions/the-science-isnt-settled-now-what/article1469050/
123806. qwertyuiop at 15:10 PM on 22 February 2010
        There is no consensus
        you do realize that there cannot be skeptics if you are talking about a theory. climate change is a theory so how can there be skiptics
123807. Ned at 13:08 PM on 22 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Marcus, I tried that as well -- but I used lower-troposphere temperatures, and I looked at July data in the northern hemisphere only (since that is what Berényi Péter says he did). He claimed "No warming for July. In this case the cooling is 0.6°C/century." Like you, I found +1.65°C/century warming for July in the northern hemisphere, using the RSS lower troposphere data for the whole period of record (1979-present). Given the very, very close match between satellite and surface temperatures, I am confident that the surface records would give similar results. It seems pretty obvious that BP has mixed something up somewhere.
123808. Marcus at 12:13 PM on 22 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        According to my plotting of global July Temperatures from 1979-2009 (RSS data for Mid-Troposphere temperatures), there has been a warming trend of +0.17 degrees per decade for July alone. For the June-August period, the warming trend has been +0.16 degrees per decade. So I'd love to know how Beranyi has gotten his figures.
123809. philipm at 12:06 PM on 22 February 2010
        The Dunning-Kruger effect and the climate debate
        There is some interesting stuff at JPL about how well CO₂ is mixed into the atmosphere. Because of the large fluxes involved it is not quite as uniformly mixed through the height of the atmosphere as oxygen or nitrogen:

        There is a definite difference in concentration between the troposphere (pretty well mixed) and the stratosphere ("old" air, CO2 concentration lags that of the troposphere by several years and the lag is greater at the higher latitudes).

        However it's clear that measuring at isolated locations should give a consistent picture of any trend. If you support the right of scientists to work without harassment and political attack, sign my petition at http://www.petitiononline.com/clim4tr/petition.html
123810. Ned at 12:03 PM on 22 February 2010
        Is CO2 a pollutant?
        KR, when using the Moon as an example, keep in mind that the Moon has a lower albedo than the Earth. So if there were no greenhouse effect, the Earth would actually be even colder than the Moon.
123811. Ned at 11:58 AM on 22 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Thanks for the heads-up on that paper, Chris. It is freely downloadable, and it's very readable. I would encourage anyone with an interest in solar/climate connections to peruse this paper.
123812. carrot eater at 10:39 AM on 22 February 2010
        Is CO2 a pollutant?
        suibhne: It's more than just CO2; water vapor accounts for more of it than CO2. You are just giving emotional objections at this point - that something just doesn't sound right to you, for unexpressed reasons. That isn't sufficient. Again, please clearly state where there is a violation of the Second Law. G&T think there is one; do you agree? As for not corresponding to reality: I've shown you that these things can be measured. Longwave IR coming down towards the surface is not at all negligible. Reality is the greenhouse effect. Without it, the Earth would be a rather cold place.
123813. Philippe Chantreau at 10:20 AM on 22 February 2010
        Is CO2 a pollutant?
        That you would total up opposing IR flows as "available" energy confirms my doubts on your overall understanding of the process. Such an abuse of language is rather suprising from someone posing as a stickler on definitions. As for this question: "do you not think this is rather odd?" No, I don't. The nice climate we've been enjoying, sustained with only 342 w/sq.m exchanged at the surface, would be the oddity.
123814. KR at 10:16 AM on 22 February 2010
        Is CO2 a pollutant?
        Gah - sorry, bad simple math, typing too fast: The moon has 107-153/2 = -23C average surface temp, versus ~15C average surface temp on Earth, difference of 38C. Difference between the moon's -23C and Earth's 15C surface temp is due to the insulation of the atmosphere, and the high levels of energy interchange at the surface are because the surface is WARM. It's that simple, suibhne.
123815. KR at 10:13 AM on 22 February 2010
        Is CO2 a pollutant?
        suibhne, the level of energy flowing/exchanging at the surface IS much larger than the level of energy at the top of the atmosphere, due entirely to the insulating properties of the atmosphere. If we didn't have an atmosphere the surface of the Earth would resemble the Moon; 107C average during the day, -153C average at night, summing to -46C surface temperature. As it is the average surface temp of the Earth is (sorry for vagueness, folks) around 15C, over 60C warmer. Without the atmosphere the surface of the Earth would quickly cool to match incoming solar irradiance. The outgoing energy from the surface (390 w/m2, plus 24 in conduction and 78 evaporative, according to the figure we've been discussing) is kept at ~15C by solar irradiance _AND_ heat reflected down from the atmosphere (342 or so?). Increasing CO2 will cause more heat to be retained by the atmosphere, directly resulting in a warmer atmosphere and surface - that's very simple. suibhne, you continue to construct incomplete thought experiments (your double IR solar panel), argue over definitions of heat and energy, and quite frankly insult other posters thermodynamic knowledge, but it really is this simple: the atmosphere insulates the earth and allows it to be >60C than the moons surface with the same irradiance. Increasing the insulating properties of the atmosphere with higher CO2 (and through positive feedback water vapor) levels will make the earth warmer. Hence global warming...
123816. suibhne at 09:59 AM on 22 February 2010
        Is CO2 a pollutant?
        carrot eater This atmospheric forcing of co2 is really powerful almost three times as much energy available at the surface as supplied by the Sun. Its a pity about the inconvenient facts of thermodynamics but they will not fade away. Any theory or computer model based on stuff like this must fail as it does not correspond to reality. I don't know who the "we" are in your last post I only speak for myself,but I never find it hard to be polite.
123817. Alexandre at 09:44 AM on 22 February 2010
        Visual depictions of CO2 levels and CO2 emissions
        RSVP, In a sense, yes. Atmosphere is a poorer radiator than solids or liquids. Gases are terrible black bodies and don't emit energy in all the Planck's spectrum as solids and liquids usually do. Don't stick so strongly to the analogy, though.
123818. chris at 09:16 AM on 22 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Mike Lockwood has just published a pertinent paper that discusses this subject in detail (along with some interesting comments on Internet-sourced confusion!). I think this paper is freely downloadable: M. Lockwood (2010) Solar change and climate: an update in the light of the current exceptional solar minimum Proc. Roy. Soc. A 466, 303-329 Lockwood Proc Roy Soc 2010
123819. Riccardo at 08:55 AM on 22 February 2010
        On the reliability of the U.S. Surface Temperature Record
        Read this: "But at face value, this plot seems to indicate that the rapid decrease in the number of stations included in the GHCN database in recent years has not caused a spurious warming trend in the Jones dataset — at least not since 1986." It's not on siting issue or UHI, but some people have problems with the decreasing number of stations in the last decades. And the quote does not come from someone from CRU, GISS or other "consensus scientist", it comes from Roy Spencer. I hope that this will slow down a bit some chattering.
123820. carrot eater at 08:29 AM on 22 February 2010
        Is CO2 a pollutant?
        suibhne: It isn't "odd" unless you can clearly state where there is a violation of the First or Second law in the greenhouse theory. G&T claim a violation of the Second Law. If you cannot articulate and defend this violation, then you must abandon G&T. This is now beyond unproductive. We are trying to be patient and polite, but patience is wearing thin.
123821. suibhne at 07:41 AM on 22 February 2010
        Is CO2 a pollutant?
        Philippe Chantreau carrot eater The definition of heat is most important and you will fall into error if you use a "pass with a shove loose definition". That's why I asked you to look up the definitions in a thermodynamics textbook. Where in the Trenberth diagram is there a violation of the Second Law? A above the Stratosphere 342w/m2-agreed? B Just above the Earths surface 390w/m2 up + (168+324)w/m2down = 882w/m2-agreed? You agree, do you not think this is rather odd? This diagram shows that the available energy at surface is almost three times that supplied by the Sun.
123822. Riccardo at 07:31 AM on 22 February 2010
        It's cosmic rays
        Turboblocke, you friend is making some confusion between Mie scattering and Twomey Effect. The latter appears to be interpreted as the explanation of the dependece of clouds albedo on droplet size. I assume this is correct. Twomey (e.g. Twomey 1977, J. Atmos. Sci. 54, 1149) did infact apply Mie scattering (with some aproximations) to clouds and not what your friend said ("greater surface area gives greater 'reflectivity'". What your friend appears to be missing is that as far as clouds are concerned one need to consider that: 1) the total mass of water is kept constant, so smaller drops means larger concentration. 2) in real clouds the droplet size is much larger than the wavelength of light (several microns and more vs rougly half a micron) 3) most of the clouds (low and medium level clouds) are optically thick and therefore single scattering aproximation breaks down. This means that the polar distribution of the scattered intensity varies only slowly, almost flat indeed. This contradicts the claim that "satellites don't measure true albedo". I'd like to add a few other comments on his claims. "models significantly over-predict temperature rise for a given level of CO2 and have to be corrected by an assumed aerosol cooling". Yes, if you give incorrect input to the models you'll get garbage for sure. Indeed, no one denies (i hope) that pollution from aerosol (sulfides in particular) has increased till roughly the '60s. Why the models should not consider this given that they do have an effect on climate? "One paper points out that there is no 'albedo' difference between southern and northern hemispheres when it is known that the aerosol concentration is much higher in the north." This is really a miopic point of view. Is albedo determined just by aerosol? No for sure. You have clouds, oceans, ice and several types of land. It is surprisingly enough that the mean albedo turns out to be almost equal in the two emisphere.
123823. Philippe Chantreau at 05:41 AM on 22 February 2010
        Is CO2 a pollutant?
        So what, you can quote a textbook with one definition and that's a big gotcha? I'm unimpressed. Heat is used loosely in many circumstances and often refers to enthalpy as well, since it can be readily translated in terms of heat. You're just playing on words, just like G&T. The wiki on heat is more informative than your definition: http://en.wikipedia.org/wiki/Heat You still haven't told us what the double sided panel was about, or where the violation of the 2nd law is. If anything you're proving that G&T are confused since they equate heat with IR in their paper. There is no heat transfer between the atmosphere and the surface. The heat transfer occurs between the surface and the atmnosphere. G&T say that, because there can be no heat transfer between atmosphere and surface, there can be no IR flowing from atmosphere to surface and that's simply stupid. The atmosphere's radiative properties owed to GH gases constrain the heat transfer, but the net heat transfer is still from surface to atmosphere. I don't know what your problem is and frankly I don't care any more.
123824. suibhne at 04:45 AM on 22 February 2010
        Is CO2 a pollutant?
        carrot eater Philippe Chantreau It has just occurred to me that perhaps you don't have any Physics text books to consult. From University Physics by Harris Benson page 382 Modern definition of Heat Heat is energy transferred between two bodies as a consequence of a difference in temperature between them. Hope that helps.
123825. Ned at 04:31 AM on 22 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        BP writes: Also, recent "global warming" is a myth. To illustrate this proposition, consider the following graph: [ snip lengthy description of DIY analysis ] Rather strange that satellites, surface stations, and measurements of ocean heat content (link 1, link 2)all perpetuate this same "myth". It's also strange that sea level continues to rise (link) due in large part to thermal expansion. Maybe you should inform the ocean that "global warming is a myth"? These are just a few examples of evidence that global warming is non-mythical. John put together a longer list back in December:
        What happened to the evidence for man-made global warming?
        • Our planet is suffering an energy imbalance and is steadily accumulating heat (Hansen 2005, Murphy 2009, von Schuckmann 2009, Trenberth 2009)
        • Animal and plant species are responding to earlier springs. Eg - earlier frog breeding, bird nesting, earlier flowering, earlier migration of birds and butterflies (Parmeson 2003)
        • The distribution of tree lines, plants, birds, mammals, insects, fish, reptiles, marine invertebrates are shifting towards the poles (Parmeson 2003)
        • Arctic permafrost is degrading (Anisimov 2006) plus warming at greater depths in the permafrost (Stieglitz 2003)
        • Global sea level rise is accelerating (Church 2006)
        • Antarctic ice loss is accelerating (Velicogna 2009), even from East Antarctica which was previously thought to be too stable to lose ice mass (Chen 2009)
        • Greenland ice loss is accelerating (Velicogna 2009, van den Broeke et al 2009)
        • Glaciers are shrinking globally at an accelerating rate (WGMS 2008)
        • Arctic sea-ice loss is accelerating with the loss rate exceeding model forecasts by around a factor of 3 (Stroeve 2007).
        • The height of the tropopause is increasing (Santer 2003, press release)
        • Jet streams are moving poleward (Archer 2008, Seidel 2007, Fu 2006)
        • The tropical belt is widening (Seidel 2007, Fu 2006)
        • There is an increasing trend in record hot days versus record cold temperatures with currently twice as many record hot days than record cold temperatures (Meehle 2009, see press release).
        • A shift towards earlier seasons (Stine 2009)
        • Lake and river ice cover throughout the Northern Hemisphere are freezing later and breaking up earlier (Magnuson 2000, Hodgkins 2005)
        • Changes to physical and biological systems across the globe are consistent with warming temperatures (Rosenzweig 2008)
        • Cooling and contraction of the upper atmosphere consistent with predicted effects of increasing greenhouse gases (Lastovicka 2008)
        • Pitcher-plant mosquitoes are genetically evolving to adapt to shifting seasons (Bradshaw 2001)
        • Distribution of plants are shifting to higher elevations (Lenoir 2008)
        See John's post for the links.
123826. carrot eater at 04:21 AM on 22 February 2010
        Is CO2 a pollutant?
        Heat transfer is the transport of thermal energy, through conduction, convection or radiation. I don't know why suibhne is trying to play with semantics, but it won't go anywhere. But let's not have that distract from the main question. Where in the Trenberth diagram is there a violation of the Second Law?
123827. Philippe Chantreau at 04:12 AM on 22 February 2010
        Is CO2 a pollutant?
        Heat, in our context is IR radiation. It is a form of energy. How exactly do you disagree with this? G&T very clearly states that no IR radiation (heat) can flow at all from the atmosphere to the surface, as a matter of principle, not degree. They have been quoted already. If you continue saying that nobody has pointed you to where they say so, you will display an obvious lack of interest for a real exchange and your posts will probably be deleted.
123828. carrot eater at 03:48 AM on 22 February 2010
        Is CO2 a pollutant?
        This is truly bizarre. Suibhne, it's been pointed out to you before. "A machine which transfers heat from a low temperature reservoir (e.g., stratosphere) to a high temperature reservoir (e.g., atmosphere) without external work applied, cannot exist — even if it is radiatively coupled to an environment, to which it is radiatively balanced. A modern climate model is supposed to be such a variant of a perpetuum mobile of the second kind." Again, this is not an argument about magnitude. It is a clear statement that G&T think there is a violation of the Second Law in here. Where is the violation of the Second Law, suibhne?
123829. suibhne at 03:11 AM on 22 February 2010
        Is CO2 a pollutant?
        carrot eater ..... The text in question in G&T has been pointed out several times already, including the figure. I asked you to show me the text and you did not. So I can only guess that you also are getting mixed up between the definition of heat and energy. If this is the case, I think that you do need to look this up in a reputable thermodynamics textbook because you obviously don't agree with me when I say it is not.
123830. suibhne at 03:03 AM on 22 February 2010
        Is CO2 a pollutant?
        Ned Steve McIntyre is very good at analysing data, he famously showed that the hockey stick graph was a joke. His site is famous for subjecting data to a more rigorous investigation than the original authors were capable of. His site does not highlight any other theories about climate change such as the solar models etc. Ned do you think that heat is exactly the same as energy? If so I think that you do need to look this up in a reputable thermodynamics textbook because you obviously don't agree with me when I say it is not.
123831. Ned at 02:27 AM on 22 February 2010
        Is CO2 a pollutant?
        I wrote: It's perfectly possible for some heat to flow from a lower temperature to a higher, as long as there's a greater flow in the opposite direction. This is the point that G&T fail to understand (or one of the points). suibhne responded: I think you are mixing up heat and energy definitions. A good thermodynamics text book will clarify the issue. No, I meant precisely what I said. The fact that the cooler atmosphere contributes to heating the warmer earth does not violate the 2nd LOT because the net heat flux is still in the opposite direction. G&T are spectacularly wrong on this, which is one (but only one) reason why their paper was greeted with such ridicule. Persisting in arguing this point, and citing G&T as if there was some merit to their nonsense, reduces your credibility and weakens the "skeptic" case. Steve McIntyre understands this, which is why he bans any discussion of G&T from his site. Here are a few examples of Steve's response when commenters have tried to bring this paper up for discussion there: "I do not want to discuss Gerlich on this site. I am not interested in expositions why the effect is impossible – it isn’t. Can people simply STOP posting 'skeptic' references on this." "Folks, I do not wish to get involved in a discussion of this paper by Gerlich and Tscheuschner. It would be far more worthwhile to discuss a good exposition of mainstream theory." Et cetera. McIntyre is smart enough to understand that hosting discussion of topics like G&T would significantly impair the credibility of his blog.
123832. carrot eater at 02:24 AM on 22 February 2010
        Is CO2 a pollutant?
        suibhne: The text in question in G&T has been pointed out several times already, including the figure. They think the greenhouse effect is in theory impossible. This is not an argument of magnitude, but of principle. And again, you can see the magnitude of the measurements. They are in line with the Trenberth diagram that you find to be absurd.
123833. Dikran Marsupial at 02:18 AM on 22 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Berényi Péter @ 52 says: "The very concept of "forcing" is flawed. Different kinds of "forcings" act on different parts of the climate system, so they are NOT interchangeable (even if they happen to have the same number as expressed in W/m2). CO2 makes stratosphere colder, increased solar activity (20% more UV) makes it hot. Forget about forcing as a unified concept, please." The fact that the forcings act differently on the stratosphere does not mean that a direct comparison of the forcings is unreasonable in judging the effects at the surface (if only as a first order approximation). "Also, it does not make much sense to use models to predict the long term effect of some input variable if those very models are proven lacking in postdiction." As GEP Box said, "all models are wrong, but some are useful"; the models have shown useful skill at hindcasting, see chapter 8 of the IPCC WG1 report and here: http://www.skepticalscience.com/climate-models.htm "Also, recent "global warming" is a myth." Can you explain the trend in the UAH satelite data then, which shows a clear warming trend over the last 30 years? http://woodfortrees.org/plot/uah/plot/uah/mean:13/plot/uah/trend "I have pulled global land surface data from ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v2/ and did some rather obvious things to it. Anyone can replicate. 1. selected northern hemisphere stations (82% of all) 2. considered temperature data for each month separately 3. used only uninterrupted series at least 20 years long, with no data missing 4. computed least square linear fit for all such 20 years interval 5. assigned slope to mid-year of 20 years run 6. averaged slopes for each (year;month) pair over set of stations 7. integrated slopes backwards in time, getting temperature anomalies relative to present" It is not at all obvious that this is a sound methodology: 2. Considering temperatures separately by month introduces quite a lot of extra variability into the analysis, especially as the data are temporally correlated, and separate analysis by months ignores that correlation. 6. Simple averaging of the trends will introduce a bias into the trends as the stations are not uniformly distributed around the Northern Hemisphere. An area weighted averaging (as used in the standard datasets) is required to get a real picture of the NH temperatures. 7. Integrating the slopes backward in time to get a temperature timeseries is not likely to be a robust procedure, as it will be very sensitive to any bias in the computation of the trends. There is a good reason why the standard datasets don't use this methodology, and I suspect that is it. A simple way to see this is to consider the error bars on the reconstruction, you are adding a new term for each step back, assuming the error bars are independent for each estimate of the trend, the error bars are the sum of the error bars on each trend estimate, which will get wider and wider the further back you go. "The findings are robust" Not making an adjustment for UHI makes the results less robust not more as you have not corrected for a known bias. Also robustness implies that you have analyzed the results to make sure they are sane, e.g. by checking that the average error between your reconstruction and the original data is the same at the start as it is at the end. "If anything, northern hemisphere climate is getting milder during last century, winters less cold, summers cooler. Exactly the pattern leading to long term ice sheet buildup, new glacial period coming." rather at odds with the satellite observations of arctic ice cover which show a significant decline in the arctic ice-sheet. Science requires self-skepticism (such as looking at the data to see if it is inline with your theories). It also takes a lot of hard study, which is why we have climatologists that have made it their lifes work to understand issues such as this. Having said which, I am no expert on time-series, you'd be better off asking tamino for his views on your reconstruction; he obviously does have a good grasp of time-series analysis. http://tamino.wordpress.com/
123834. joseph449008 at 02:16 AM on 22 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        @Berényi Péter:

        and did some rather obvious things to it. Anyone can replicate. 1. selected northern hemisphere stations (82% of all) 2. considered temperature data for each month separately 3. used only uninterrupted series at least 20 years long, with no data missing 4. computed least square linear fit for all such 20 years interval 5. assigned slope to mid-year of 20 years run 6. averaged slopes for each (year;month) pair over set of stations 7. integrated slopes backwards in time, getting temperature anomalies relative to present

        That's not obvious at all. How do you get temperature anomalies by "integrating slopes backwards" and what's the rationale? Isn't it easier to subtract a baseline from the mean temperature? Your claim to have found no warming trend is extraordinary, and I'm willing to bet your calculations are mistaken.
123835. suibhne at 02:04 AM on 22 February 2010
        Is CO2 a pollutant?
        carrot eater ..... The text of G&T simply does not support that. G&T are saying zero radiation from .... I think you must be reading a different copy from me. Where do G&T say that there is Zero radiation from Atmosphere to Earth! The main point I picked up was that the Woods experiment showed that radiation from the Earth to atmosphere is very small part of the total energy transfer. It then follows that re-radiation back to the surface is even smaller so that for practical purposes it can be ignored. This is quite common in Physics. A typical problem might be: A stone is dropped vertically from a cliff and lands 3seconds later. How high was the cliff.(ignore air resistance) On another tack and nothing to do with the previous discussions. What is the average path length travelled in the atmosphere by a suitable IR photon before it is absorbed by a CO2 molecule? I have heard quotes from 10m to 10 Km
123836. carrot eater at 00:42 AM on 22 February 2010
        Is CO2 a pollutant?
        suibhne So you accept both walls will absorb radiation emitted by the other wall. And that's it. The end. You've just refuted G&T. We have shown you that it is this basic concept that G&T are refusing to accept. You think it's a matter of magnitude, of just how much radiation from the atmosphere is absorbed by the surface. The text of G&T simply does not support that. G&T are saying zero radiation from the colder atmosphere is absorbed by the Earth. It's a matter of principle, and as such, the game is over. And anyway, the magnitudes are fine. They have been measured.
123837. suibhne at 00:38 AM on 22 February 2010
        Is CO2 a pollutant?
        CBDunkerson G&T have no problem with your blanket analogy -stops heat loss due to conduction and convection. The consider that heat loss by radiation is much smaller and that re radiation from the atmosphere is so small that it can be ignored. Even for radiation the heat flow is always from higher to lower temperature.
123838. RSVP at 00:24 AM on 22 February 2010
        Visual depictions of CO2 levels and CO2 emissions
        Alexandre This issue can be made as complicated as one wants. On the other hand, one can also construe a model with minimal simplicity for the purpose of making convincing arguments about AGW, or at least leave people with a proper sense of its significance. The way it stands now, with snow blowing in my face every winter, I have to see myself as a frog that needs to jump out of a pot that is going to boiling ever so slowly. Perhaps you can help me ignore the snow, and instead visualize the boiling pot in which I sit. And as you offer to answer questions, I appreciate the offer. I asked one question above. It was whether the atmosphere itself acts as a poorer radiator than solids or liquids? (in other words the ground or the oceans) And I asked this because this is the only way that the Earth could accumulate more thermal energy. (Even then, this piece of data is not sufficient, given that if nights and winters are long enough to allow a complete discharge, this would still have no incremental effect.) In either case, would you know the answer to the question? Thank you.
123839. CBDunkerson at 00:18 AM on 22 February 2010
        Is CO2 a pollutant?
        Suibhne, no Ned is completely (and obviously) correct. THINK about it. How would heat 'know' not to flow in a given direction? It doesn't... it radiates equally in all directions. There is no 'magical quantum traffic cop' preventing heat from traveling from a cold substance to a hot one. It happens all the time. However, since the hot substance is giving off MORE heat the amount flowing from it to the cold substance is greater and the NET change is always from the hot to the cold. The amount of heat coming up from the Earth is greater than the amount absorbed and reflected back (obviously, since the latter can only be a subset of the former), and thus the NET flow >is< from hot planet up into cold space... but the downward heat is greater than it would be without GHGs. It should be painfully obvious that this is true. Otherwise blankets could not work... clearly the blanket is colder than the human body so if G&T weren't liars or fools they're postulates would mean that since the human body is generating all of the heat in the 'blanket & body' system the heat MUST all flow from the body up to the blanket and the body will never be any warmer than it was without the blanket. That is, of course, complete nonsense. Some of that body heat is retained by the blanket and returned back down to the human, flowing from colder blanket to warmer human and making the human warmer than they would have been without the blanket.
123840. suibhne at 00:09 AM on 22 February 2010
        Is CO2 a pollutant?
        carrot eater ......Say you've got one wall at 25 C. Directly facing it is another wall, at 50 C. We are probably not in disagreement about this . Both walls will radiate to each other but the flow of heat is from the hotter wall to the colder. Where there does seem scope for disagreement is in the respective size of the heat loss from the surface of Earth by conduction convection and radiation
123841. suibhne at 23:54 PM on 21 February 2010
        Is CO2 a pollutant?
        Ned That's the net flow of heat. It's perfectly possible for some heat to flow from a lower temperature to a higher I think you are mixing up heat and energy definitions. A good thermodynamics text book will clarify the issue.
123842. suibhne at 23:48 PM on 21 February 2010
        Is CO2 a pollutant?
        carrot eater Thanks for posting these leads will look at them in more detail later. I realise that the diagram are discussing is averaged over say one year and you did not disagree that the readings I assumed that the thermopile would take. Yet you find nothing odd with them! Philippe Chantreau Given that we are talking about properly obtained and averaged values are you still happy with these readings?
123843. Ned at 23:37 PM on 21 February 2010
        Is CO2 a pollutant?
        suibhne writes: The flow of heat will always be from a higher to a lower temperature unless work is done. That's the net flow of heat. It's perfectly possible for some heat to flow from a lower temperature to a higher, as long as there's a greater flow in the opposite direction. This is the point that G&T fail to understand (or one of the points). Thus, the atmosphere is cooler than the surface, so there's a net flow of heat from the surface to the atmosphere. That net is a result of a large flux from the surface to atmosphere and a smaller one from the atmosphere to the surface. Warming the atmosphere will increase the latter, therefore warming the surface. The fact that G&T fail to understand this completely non-controversial and very basic point ought to clue you in to the lack of merit in their paper as a whole.
123844. HumanityRules at 23:27 PM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Ned 26# I raised the point of regional nature of solar affects because I've seen this used to dismiss the impact of other climate processes. I agree with you on the CO2 pattern of warming, if it exists. I guess this argument can be ignored in the future as all climate change has a regional nature? Marcus #32 Graphs tend to show the MM spanning 50years within a period of 100+years of low sunspot activity rather than the 300years you suggest. There also doesn't appear to be 250years between the end of this minima period and today. Whatever the time periods are you suggesting that the LIA produced 1.5oC of cooling (given a recovery of 25*0.06)? Because even this seems higher than the modelling would allow. GFW 34 On volcanos do you have a reference for that work? I found this review which lists volcanos from 1500 on ward with DVI greater than 500. There are 3 in 1500's, 7 in 1600's, 7 in 1700's and 7 in 1800's. Given that 1750 is about the time when this cold period was ending it seems there wasn't any significany drop off in volcanic activity after this period to allow warming. Interestingly they only list 3 for 1900's, although you mention several more after the publication date, seems if you are looking for unusually low levels of volcanic activity look to the 20th C. Volcanoes and climate: recent volcanological perspectives. D. K. Chester (1988) Progress in Physical Geography 12, 1-35
123845. Berényi Péter at 23:26 PM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        #0 Posted by John Cook at 14:14 PM "it's helpful to compare the radiative forcing from a cooling sun to the radiative forcing from anthropogenic greenhouse gases" No, it is not. The very concept of "forcing" is flawed. Different kinds of "forcings" act on different parts of the climate system, so they are NOT interchangeable (even if they happen to have the same number as expressed in W/m2). CO2 makes stratosphere colder, increased solar activity (20% more UV) makes it hot. Forget about forcing as a unified concept, please. Also, it does not make much sense to use models to predict the long term effect of some input variable if those very models are proven lacking in postdiction. Also, recent "global warming" is a myth. To illustrate this proposition, consider the following graph: http://kign.org/Northern_hemisphere_temperature_anomaly.jpg I have pulled global land surface data from ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/v2/ and did some rather obvious things to it. Anyone can replicate. 1. selected northern hemisphere stations (82% of all) 2. considered temperature data for each month separately 3. used only uninterrupted series at least 20 years long, with no data missing 4. computed least square linear fit for all such 20 years interval 5. assigned slope to mid-year of 20 years run 6. averaged slopes for each (year;month) pair over set of stations 7. integrated slopes backwards in time, getting temperature anomalies relative to present Findings: 1. No warming for summer since mid thirties of last century. In fact, there is a 0.2°C/century cooling trend. 2. No warming for July. In this case the cooling is 0.6°C/century. 3. Springtime warming stopped in mid eighties 4. Only winters are getting consistently warmer, even this trend is flatting out recently (since 1995) 5. Otherwise annually averaged temperature anomaly trend looks like advertised The findings are robust. 1. Have not made any adjustment for UHI (Urban Heat Island) effect. Warming is overestimated. 2. Gregorian calendar effect is not corrected for. Since 1900 spring equinox is moving to ever earlier dates which introduces a spurious springtime warming trend. It will be reset only in year 2100 with no 29 February in that year. If anything, northern hemisphere climate is getting milder during last century, winters less cold, summers cooler. Exactly the pattern leading to long term ice sheet buildup, new glacial period coming. GHCN data go back to mid eighteenth century. It is not shown on graph (more cranky, wider margins of error), but looks like winters were even colder back then (up to 3°C) while there is no trend in summer temperatures. Little ice age was not uniformly colder, perhaps. At he end of 1820s summer temperatures were just as warm as they are today, winters much colder. How do models replicate this pattern for reduced solar activity?
123846. suibhne at 23:25 PM on 21 February 2010
        Is CO2 a pollutant?
        doug_bostrom The flow of heat will always be from a higher to a lower temperature unless work is done. Heat can be prevented from flowing by addressing conduction convection and radiation issues I think we are all agreed on that I hope. Where the disagreements arise is on the overemphasis on radiation. I have a Physics degree and even my Thermodynamics textbook by Adkins(1985) gives the now abandoned Greenhouse explanation. Apparently he was not aware of the experiment by Woods. It was therefore important that G&T should clear up any doubts on the matter.
123847. BC at 23:17 PM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        I've just figured it out. It'll be a randomly placed volcano.
123848. ThosThos at 22:57 PM on 21 February 2010
        Did Phil Jones really say global warming ended in 1995?
        Can I try and clarify for the non-statisticians the importance, or otherwise, of statistical significance. Statistical significance, in the current context, means that 95% of the time we can be satisfied that our trend is valid. The uncertainty lies in the fact that we are not looking at all possible data, either because we do not have it, or because we are choosing a subset. As Jones says, the longer the period we are looking at data, the more certain we can be that trend is meaningful, and the less stringent the significance level has to be. Lack of statistical significance can be overcome by choosing a lower significance level. For example, at the 90% level, we can say that trend is valid 90% of the time. Obviously, lower values of trend will meet this weaker test. So, statistical significance is a statistical artifice, a means of measuring uncertainty. Lack of it does not mean a physical relationship does not exist, in this case rising trend, just that it does not pass the chosen test level. This is a major weakness of statistical relationships, particularly over a short period of time.
123849. BC at 22:35 PM on 21 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Does anyone know why there's a fairly substantial dip in the graph, fig 2, in about 2020?
123850. Alexandre at 22:33 PM on 21 February 2010
        Visual depictions of CO2 levels and CO2 emissions
        RVSP, There's another part of the story that wasn't brought about so far, which is the energy received by the planet (that's a limitation of a blog debate as compared to a proper class, with a qualified teacher). There's the energy received from the sun, and there's the energy emitted by the planet. When both are equal, the system is in an equilibrium. The planet always "leaks" (i.e., emits energy). When you increase the CO2 you reduce that leakage. This retains energy, and causes the temperature to rise. This higher temperature, in turn, rises the emmission of energy (the Iout you saw on the mnodel) *until* it is in equilibrium with the received energy again. The leakage continues, as always. But now the temperature does not rise anymore, having reached a new balance, in a warmer planet. As always, feel free to ask any further questions. As I said, this is my pleasure. But if you have the time or energy for this, I would suggest one of the many tutorials online there are on the subject, for example: University of Chicago - the actual classes of the Global Warming Physics basics (for non-science students) on video. Online Textbook from the Université Catholique de Louvain, Belgium (in English). A slightly different, historical approach, on Spencer Weart's Discovery of Global Warming.

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