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

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Comments 100101 to 100150:

  1. Lindzen and Choi find low climate sensitivity
    Eric, That's fine with me, please request my email address from John Cook via the contact form so I don't have to print it out publicly." There is no reason why we can't continue to discuss this here. It is completely related to the subject, though somewhat indirectly.
  2. Lindzen and Choi find low climate sensitivity
    KR, "RW1 - You stated that "239 W/m^2 of the power at the surface has to come from the Sun, which means the back radiation can't be 333 W/m^2". Thank you, that indeed clarifies your position." What I meant was 333 W/m^2 can't be coming from the atmosphere, which Trenberth vaguely designates as "back radiation". "Power involves net energy flow - the internal interchange between atmosphere, ground, and space has a net energy flow of ~240 W/m^2; the internal dynamics and interchanges are related, but not directly, nor in a scalar fashion." And what is the net energy flow at the surface? It's 396 W/m^2 (according to Trenberth's diagram). Power equivalent temperature at the surface is calculated via Stefan-Boltzman. We can argue all you want about what the energy flows may or may not be, but this doesn't change the power flux at the surface, which is what the gain is derived from. "I suggest you then take the discussion to the appropriate thread, The greenhouse effect and the 2nd law of thermodynamics, where backradiation is clearly discussed. You are conflating power (energy going somewhere, doing work) with the energy involved in the Earth's temperature." No I'm not. All I'm doing is converting surface power to temperature via Stefan-Boltzman. "Power comes in from the sun, power goes out to space, but the internal temperature of the Earth and atmosphere is determined by the temperature required by dynamic equilibrium between these two numbers, based upon the thermal and emissive properties of surface and atmosphere, and not just a scalar value of the input/output power as you have claimed." The grey body components I think you may be referring to don't matter for the purposes of gain, because the gain is based on surface power emission and the surface is considered to be very close to perfect black body radiator where "e" equals 1.
  3. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    #4: "Have'nt we been coming out of an ice age for the last 10,000 years?" If you believe that, you really must tell that to the deniers who claim 'we're going into an ice age!'. And the ones who claim 'its just warming after the LIA!'. And the ones who claim 'it's UHI!' or 'it's waste heat'. Because you can't have it both ways. A double denial = agreement. In short, no. Technically, we are still in an ice age, but the glacial stage of it ended approx 10kya. If, as some claim, we are warming on a 'ramp' of 1.2 deg/century because of the end of this glacial, that would be 120C. See Ice data made cooler for some nice graphics. But you do suggest an interesting exercise: take a graph like Fig 1 from here and plot it on a 30 year time scale. Those 'sharp slopes' disappear ... except the one that got going in the last century or so.
  4. Lindzen and Choi find low climate sensitivity
    That's fine with me, please request my email address from John Cook via the contact form so I don't have to print it out publicly.
  5. Stratospheric Cooling and Tropospheric Warming - Revised
    RSVP - I have to disagree with your post completely; the chamber containing GHG's in my example will show the plate and chamber temps rising faster than in the non-GHG case. Note: in the following example the actual numbers are whole cloth - but they illustrate the point, and the directions of change observed Take two insulated chambers (as before) with black plates at the back, no GHG's in the air, and a 100W bulb (visible light) shining in. At dynamic equilibrium the plates (at some temperature) will radiate 100W of thermal energy back out. Add GHG's to one chamber, keeping the pressure the same (to avoid any other effects). The plate receives 100W, radiates 100W, but now (let's say) 10W of IR get absorbed by the GHG's. They then warm and radiate 10W IR in all directions (atmospheric equilibrium). The box now receives 100W, but only emits 95W (imbalance). The plate receives 100W of visible light, plus 5W of IR backradiation. Not surprisingly, the plate warms up. The plate in the non-GHG box does not change temperature. At dynamic equilibrium the (warmer) plate will receive ~105W of radiation, lose the same 105W (mostly radiation), the atmosphere will radiate something like 10W (all directions), and the box will once again emit 100W of IR. With the plate and air in the box warmer than the non-GHG box.
  6. Lindzen and Choi find low climate sensitivity
    archiesteel, "A simple yes or no will suffice." No.
  7. Lindzen and Choi find low climate sensitivity
    RW1 - You stated that "239 W/m^2 of the power at the surface has to come from the Sun, which means the back radiation can't be 333 W/m^2". Thank you, that indeed clarifies your position. I suggest you then take the discussion to the appropriate thread, The greenhouse effect and the 2nd law of thermodynamics, where backradiation is clearly discussed. You are conflating power (energy going somewhere, doing work) with the energy involved in the Earth's temperature. Power comes in from the sun, power goes out to space, but the internal temperature of the Earth and atmosphere is determined by the temperature required by dynamic equilibrium between these two numbers, based upon the thermal and emissive properties of surface and atmosphere, and not just a scalar value of the input/output power as you have claimed. Power involves net energy flow - the internal interchange between atmosphere, ground, and space has a net energy flow of ~240 W/m^2; the internal dynamics and interchanges are related, but not directly, nor in a scalar fashion. And, as archiesteel noted, you have made no solid case for low climate sensitivity.
  8. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    Have'nt we been coming out of an ice age for the last 10,000 years? And if so, how is it possible to distinguish the effects of this trend with those possibly caused by man? How different would changes in albedo be as a result of natural Artic ice receding at the "last hours" of an "end of ice age" cycle? Referring back to past climate change... http://www.skepticalscience.com/What-does-past-climate-change-tell-us.html Even in the interim, (as per Figure 1 of the link), huge excursions existed in the past without man...puntuated changes exhibiting sharp slopes which if plotted over a thirty year window would also give the impression of a continuous trend.
    Response: This comment is off-topic - the "we're coming out of an ice age" argument has been examined in detail (in fact, at a Basic, Intermediate and Advanced level).
  9. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    http://data.giss.nasa.gov/gistemp/ has a link to Global Maps and station data. Is an average world temperature really what you want? The anomaly is normally used as it is less sensitive to station drop out.
  10. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    The role of the sceptic is to point out the flaws in the popular comments on AGW, of which this thread is a good example. If you see a signpost pointing in the wrong direction, you perform a service by taking it down. There are several different popular theories of AGW, and like all “scientific” theories they stand or fall on the principle of falsification. As Einstein said, 20,000 observations may confirm a theory – it only takes one to refute it. Here are three: 1) One view of AGW (which I suspect caerbannog 28 favours)is that CO2 will accumulate in the cold, dry, upper atmosphere where water vapour cannot interfere with its impact. The energy absorption in this region will increase rapidly because CO2 will be the principal “greenhouse” gas. The temperature increase will then cascade through lower layers, warming the surface. You can test idea this by comparing the UAH satellite temperature trends over the last 30 years: Lower troposphere ; 1.4 degrees C per century Upper troposphere : 0.5 degrees C per century, a factor of almost three in the wrong direction 2) Another popular theory is the “back-radiation” idea. A single-slab model of the atmosphere will absorb heat from the surface, radiate half to space, and half back to warm the ground. Relative to a bare rock earth, the surface must radiate double the energy, because the output to space from the atmosphere must be the same as the solar input. To achieve this, the surface temperature must increase by a factor equal to the fourth root of 2, or 19%. From a bare rock temperature of 255 K, this theory gives an increase of 48 degrees C, which is plausible. To test this theory, RWWoods built his greenhouses. One, made of glass, absorbed outgoing radiation. The other, made of salt, did not. There was no measurable temperature difference in the interiors. 3) All CO2 based AGW theories depend on the ability of CO2 to absorb energy. If the molecules could trap and transfer heat to the atmosphere, increasing the CO2 concentration in air would generate steadily increasing temperatures. Angstrom (he of the unit) tried it. He found that, as soon as all the available energy output from a source had been absorbed, temperatures in the air ceased to rise. You can see a comparison of air (385 parts per million) and 100% CO2 here: http://www.espere.net/Unitedkingdom/water/uk_overview.htm
    Moderator Response: [muoncounter] Vastly off-topic, which quickly leads to deletion. All three of your 'signposts' are thoroughly discussed and dismissed in other threads. Try using the search box to find more appropriate places if you want to rehash these denial 'chestnuts'.
  11. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    In western europe (Belgium) its now very hard to keep people awake about the GW danger. We have had 53 days of snow this year (a new record). Most people don't understand the difference between weather and climate and between cold and snow. Pfff. Is there a good website where you can see the average world temperatures?
  12. Did Global Warming stop in 1998, 1995, 2002, 2007, 2010?
    Those green and pink lines are interesting and disturbing, haven't seen that kind of analysis of the El Nino/La Nina contrasts before. The current La NIna, in Australia at least, seems to be an especially strong one, with record rainfall events and record flooding all over the place. Is this perhaps the start of another "jump" in La Nina events, to be followed, by the look of that graph, by a particular severe El Nino and a new level for those horrific (in Australia at least) events? Intuitively, more heat in the oceans and atmosphere should strengthen both La Nina and El Nino, but I had not previously seen an analysis that confirms this intuition. Oh, and Happy New Year to John Cook and all the regulars at SkS.
  13. Stratospheric Cooling and Tropospheric Warming - Revised
    KR #86 If the mixture in the chamber is observed to get warmer for containing a GHG, temperature of the back plane surface upon which the light is shining can only be taking that much longer to rise. A fair experiment would include monitoring both temperatures over time and plot comparative profiles, with and without "GHGs". In these plots, what you should find the plate surface taking that much longer to rise, owing to the GHG picking up this same "fixed sum" energy. The warmed gas should then act as a vehicle for heat transport, not unlike occurs for the convective cooling of a fluid on a solid. The cylinder's construction (or configuration) will then determine to what extent this heated gas can help cool the back plate and the gas just above it. Unless the experiment is set up with provision to replicate the equivalence of an open sky with pressure dropping as you go upward, etc., its value may be limited in "proving" anything. At least as a thought experiment it may provide some food for thought, however given what has already been said, this too is doubtful.
  14. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    @gc: "Falling temperatures are much more dangerous than rising temperatures" We're not dealing with falling temperatures.
  15. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    @Camburn: "Stoma is not perfect to detect levels of co2, and ice core samples are not perfect either." Ice cores are a lot more precise than plant stoma. "There is considerable literature showing that ice cores difuse much more than previously thought." Not really. "The error bars indicate that recent past co2 could have been as low as 195ppmv or as high as 395ppmb. This is in line with the stoma research." Do you have sources to support these affirmations?
  16. The Hitchhiker’s Guide to the AGU Fall Meeting
    @HR: do you know what the AGU's official position on AGW is?
  17. It's Pacific Decadal Oscillation
    @NETDR: "If that is what you really think I said you are simply wrong or are trying to distort my position so badly that I can't recognize it." Well, you're the one bringing up the LIA in the PDO thread, not me... As I said, it's a typical tactic for contrarians to jump from one topic to the next when they get caught in their own contradictions. (Oh, and BTW, AFAIK means "as far as I know"...)
  18. Lindzen and Choi find low climate sensitivity
    @RW1, Eric, I suggest you exchange e-mails and take this offline, that discussion seems to be getting nowhere. In fact, the useless (and increasingly off-topic) back-and-forth seems to be only designed to waste space. RW1, why didn't you respond to my earlier request, which I made at your invitation? If you wanted to give anyone the impression that you were afraid to reply, it was a resounding success. *Nothing* you have written makes a solid case for sensitivity (with feedbacks) being lower than 3C. Why even keep up this charade?
  19. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    @anastrophe: "@archiesteel: um, that's not how science works. science needs to show that recent extreme weather events have been made worse." Science does not respond to your whim. Science tries to explain observed phenomenon. What to do about what science tells us is another matter entirely. "so far, if it seems to support the AGW theory, then AGW proponents claim that weather events have to do with changing climate." No, they don't. Weather is weather, and climate is climate. Don't use strawman arguments if you want to be taken seriously. "witness the dismissal of last winter's record snowfalls in the US, and dismissal of this winter's crippling snow in europe - all called "just weather". Indeed, because when you focus on just these events (i.e. cherry-picking) you don't get the correct picture. Climate is global, and so you must look at global temperatures. Last winter was warmer than average globally, and the coming winter probably even so. Sorry for completely destroying your argument, but is *is* pretty old. "a heatwave? why, that's not weather, that's clear and present proof of global warming!" Strawman argument. No one says this. "it's for those claiming that there is harm to show that harm has occurred." Tell that to residents of the Maldives. "Hope for the best, expect the worst" is the best survival strategy. If it were up to you, we'd wait until the whole neihborhood was ablaze before calling the fire dept.
  20. Lindzen and Choi find low climate sensitivity
    KR, "As to the science: The information I linked in this post concerns the actual physics of thermal radiation. It's extremely clear you have not read that link, and do not understand the Stephen-Boltzmann equation." I'm well aware of the physics of thermal radiation and that equation. The surface of the earth is considered to be very close to a perfect black body radiator, so an emissivity of 1 can be used (no value for "e" is required because e = 1). "About 240 W/m^2 power arrives from the sun, ~239 W/m^2 leave, with ~0.9 W/m^2 imbalance. That's the Earth system from space." If there is warming occurring, yes. "The 396+80+17 leaving the surface (into the atmosphere and space) and the 333 back-radiation are aspects of the temperatures of the surface and atmosphere that are required to radiate 239 W/m^2 to space as thermal radiation according to the Stephen-Bolzmann relationship!" This still doesn't change the fact that for power in = power out, 239 W/m^2 of the power at the surface has to come from the Sun, which means the back radiation can't be 333 W/m^2. Again, if you're claiming I'm wrong, show me the power in = power out calculations that demonstrate it (239 W/m^2 in and out). "Your 'gain' is not a constant, not an input, but a result of thermodynamics and radiative physics. And your reliance on lumping all of that into a non-constant number (based, apparently, on a single website with non-reviewed opinions), rather than using the actual physics, has led you into what appears to me to be a web of extremely confusing statements, including your incorrect posts on "halving" TOA forcings, huge mis-scaling of CO2 forcings, claims of negative feedbacks, etc." The gain is simply the ratio of surface power to post albedo solar power. The physics of surface power emission and temperature are dictated by Stefan-Boltzman, as mentioned above. I never claimed the gain is a constant - I know it varies and have stated so. I've been using the gain mainly as an average general response of the system to radiative forcing. "Back on the topic of climate sensitivities - I would recommend you read the Climate sensitivity is low rebuttal, read a few of those papers, and learn about the actual physics involved. I'll take a look at them, but I think you may be confused because you're not equating power with temperature via Stefan-Boltzman.
  21. It's the sun
    Cool Papa Bell was attributed to have said (OK, Satch said it) that Ali quote about a half-century before Ali. If we say "waste heat" we'll draw a cool mill...then John could charge admission & make this site a revenue source instead of sink... The Yooper
  22. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    Re: muoncounter (86)
    ♪♫♪♫ "Oh, Canada, where the acid-rain falls freely on the oil-shale-besotted plains..." ♫♪♫♪
    (with nary a dint of effort, I can turn any tragedy into a Rodgers and Hammerstein musical) We should be so lucky to get the full 200 years of this post to double our atmospheric concentrations of CO2... Thanks for the kind words & same to you, muoncounter, same to you. The Yooper
  23. It's the sun
    Reminds me of the world's fastest climatologist, Muhammad Ali. Sucker bet on hitting the thou. If I took it, all you'd need to do is drop the words 'climate sensitivity' in here.
  24. Lindzen and Choi find low climate sensitivity
    RW1, we are so far off the original topic of climate sensitivity from satellite measures that it's not even remotely funny. As to the science: The information I linked in this post concerns the actual physics of thermal radiation. It's extremely clear you have not read that link, and do not understand the Stephen-Boltzmann equation. About 240 W/m^2 power arrives from the sun, ~239 W/m^2 leave, with ~0.9 W/m^2 imbalance. That's the Earth system from space. The 396+80+17 leaving the surface (into the atmosphere and space) and the 333 back-radiation are aspects of the temperatures of the surface and atmosphere that are required to radiate 239 W/m^2 to space as thermal radiation according to the Stephen-Bolzmann relationship! Your 'gain' is not a constant, not an input, but a result of thermodynamics and radiative physics. And your reliance on lumping all of that into a non-constant number (based, apparently, on a single website with non-reviewed opinions), rather than using the actual physics, has led you into what appears to me to be a web of extremely confusing statements, including your incorrect posts on "halving" TOA forcings, huge mis-scaling of CO2 forcings, claims of negative feedbacks, etc. Back on the topic of climate sensitivities - I would recommend you read the Climate sensitivity is low rebuttal, read a few of those papers, and learn about the actual physics involved. At this point, however, you haven't said anything new (or, in my opinion) correct in this thread for several hundred exchanges, and I will not be continuing my posts on the thread unless that changes.
  25. It's the sun
    Re: muoncounter (763) And you can't have the speed of darkness without the Sound of Silence By 2012, when the sun is really cookin' and the Arctic ice recedes from the pole for the first time in unknown millennia, enquiring minds will want to know: Just how did those Mayans know? I bet this thread hits 1,000 comments before spring... The Yooper
  26. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    #84: Oh, Canada! Wasn't that the place where the warming is much faster than the global average? The slope of the 30-year trend in this region is 5 to 6 C/century -- a rate of warming that's much higher than the rest of the world. Happy holidays to you and yours!
  27. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    "There is considerable literature showing that ice cores difuse much more than previously thought." Well, Camburn, provide references that support your case. Hopefully ones that spell "Diffuse" correctly. And are published in reputable venues.
  28. Lindzen and Choi find low climate sensitivity
    I think I now see where the confusion is coming from. 396 W/m^2 - 161 W/m^2 = 235 W/m^2. This means, according to the diagram, 235 W/m^2 of the power at the surface comes from the atmosphere, but 78 W/m^2 of the power from the atmosphere is from the Sun. So really only 157 W/m^2 is coming from the atmosphere (235 - 78 = 157) and 239 W/m^2 at the surface power is coming from the Sun (239 + 157 = 396 W/m^2). What a mess!
  29. It's Pacific Decadal Oscillation
    #38: " ... confusing the fast warming from 1978 with the long slow warming from 1880 to 2010." Yeah, that's confusing all right. Fast warming sure looks different from slow warming. "nor CO2 IMHO" So we'll go with your opinion, then. Works for me. "The climate is complicated ... " So maybe we need some actual facts and maybe even one of those easily confused scientists to sort things out? " ...is not a reason to exclude them as part of the answer." But its absolutely necessary to exclude anthropogenic CO2 as part of the answer. Yeah, that makes sense.
  30. Lindzen and Choi find low climate sensitivity
    Eric, I think he's getting 169 W/m^2 by adding the 78 W/m^2 of power from the Sun absorbed by the atmosphere. 91 + 78 = 169. But that 78 W/m^2 is from the Sun. 78 W/m^2 + 161 W/m^2 = 239 W/m^2 from the Sun. Do you see how this shows that 239 W/m^2 of power at the surface has to come from the Sun?
  31. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    Actually, we went through this specific issue with GC on the Canada thread, specifically comments 51-72 (changes in Cold-Related-Mortality vs changes in Heat-Related-Mortality in a warming world). The Christidis et al study, IIRC. Human adaptation to cold is better than to warm. We can always burn enough CO2 to keep the ice ages at bay. Unfortunately, due to the rising obesity trends, there's a limit to modifiable behaviours to deal with heat and humidity. JunkScienceCO2Science is a big disinformer site. The Yooper
  32. Lindzen and Choi find low climate sensitivity
    Eric, Trenberth is showing 169 W/m^2 being emitted by the atmosphere out to space and 70 W/m^2 through the transparent window for a total of 239 W/m^2. Where is he getting 169 W/m^2 from?
  33. It's the sun
    #762: Eric, We've been through the cosmic ray discussion many times. There is no consistent evidence of any such effect. "the cooling would not be instant due to thermal inertia (i.e. the ocean is storing the cooling)" The solar max occurred in the late 50s. Sixty years later, still no cooling. And for your own benefit, please don't ever say something 'stores cooling' in any public forum. It's like asking what is the speed of darkness?
  34. Lindzen and Choi find low climate sensitivity
    In #314, 326 W/m^2 is the total power absorbed by the atmosphere. I mean to specify that.
  35. The Hitchhiker’s Guide to the AGU Fall Meeting
    Next year we should have a Skeptical Science fans evening out!
    Response: [John Cook] Sounds like a great idea. Hoping I can make it (getting to the 2011 AGU somehow is now an ambition of mine).
  36. actually thoughtful at 15:14 PM on 27 December 2010
    The Hitchhiker’s Guide to the AGU Fall Meeting
    I thought we killed UHI pretty conclusively at http://www.skepticalscience.com/Does-Urban-Heat-Island-effect-add-to-the-global-warming-trend.html
  37. Lindzen and Choi find low climate sensitivity
    Eric, In the Trenberth diagram, 161 W/m^2 is the designated amount of power from the sun at the surface. The surface power is 396 W/m^2. 396 W/m^2 - 161 W/m^2 = 235 W/m^2 (from the atmosphere). 396 W/m^2 - 70 W/m^2 (through transparent window) = 326 W/m^2. 326 W/m^2 - 235 W/m^2 = 91 W/m^2 (total directed up out to space by the atmosphere). 91 W/m^2 + 70 W/m^2 = 161 W/m^2 leaving (239 W/m^2 needed). Do you see how this shows that for power in = power out, 239 W/m^2 of the surface power has to come from the Sun?
  38. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    #79: "Falling temperatures are much more dangerous" We've been through this elsewhere on SkS; you can find it if you search. The research says it's about a wash. The major difference being hot weather health effects are more immediate; cold weather effects take longer to make a statistical impact, if I recall correctly.
  39. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    gallopingcamel #79 - I've found that uninformed "common sense" is usually wrong. Anyway we're not talking about falling vs. rising temperatures. We're talking about rapidly rising vs. hopefully stabilizing temperatures. Camburn #81 - my philosophy is not to believe what random people on the internet say unless they're able to provide supporting evidence. If there is "considerable literature", surely that won't be a problem.
  40. CO2 lags temperature
    #218: "now seems clear that GW is the cause of the increased CO2 in the atmosphere" I wonder how exactly that works. Warming increases CO2? Where does it come from? Why did rapid warming start well after the rapid buildup in atmospheric CO2 that began after WW2? Or is that the preconceived notion you came in with?
  41. Lindzen and Choi find low climate sensitivity
    Eric, Show us the power in = power out calculations that demonstrate what you're talking about.
  42. Lindzen and Choi find low climate sensitivity
    Eric, "RW1, fig 1. The 239 is power into atmosphere plus surface. The diagram that is linked in post 298 is wrong since it shows all 239 hitting the surface ignoring the 78 of incoming solar that is absorbed by the atmosphere (Trenberth fig 1). Similarly in post 298, the (385-93) / 2 is wrong because it ignores the heat transfer into the atmosphere by thermals and convection (i.e. evaporation) along with the 78 incoming absorbed in the atmosphere. Where is the total power coming from at the surface if not from the combined sources of the Sun and the atmosphere? If the power at the surface is 385 W/m^2 and the incoming power from the Sun is 239 W/m^2, how can the remaining 146 W/m^2 not be the amount coming from the atmosphere? If it's not the atmosphere, where is the power coming from? If 239 W/m^2 is the post albedo power entering and the power leaving, how can less than 239 W/m^2 of the surface power come from the Sun? Where is the extra energy coming from? I assume you know that the law of conservation of energy dictates that atmosphere cannot create any energy of its own - all it can do is redirect it and slow its release out to space.
  43. Lindzen and Choi find low climate sensitivity
    RW1, fig 1. The 239 is power into atmosphere plus surface. The diagram that is linked in post 298 is wrong since it shows all 239 hitting the surface ignoring the 78 of incoming solar that is absorbed by the atmosphere (Trenberth fig 1). Similarly in post 298, the (385-93) / 2 is wrong because it ignores the heat transfer into the atmosphere by thermals and convection (i.e. evaporation) along with the 78 incoming absorbed in the atmosphere.
  44. CO2 lags temperature
    Re: MikeC (218)
    "Firstly, what is the mechanism for the reversal of global warming? Is this when the CO2 levels in the atmosphere reach saturation?"
     Two part answer to that: 1. CO2 long-term drawdown is by chemical weathering (hundreds of thousand year timescales) and by biological sequestration (oceanic life forms sinking into the deeps). After CO2 is in the upper atmosphere, residence time is on the order of millennia, essentially. See here and here. 2. The globe is warming because the Earth's radiation budget is out of balance. All things being equal, as long as mankind is adding sequestered carbon back into the carbon cycle, the energy budget will be imbalanced and the warming will continue. If CO2 emissions were cut to zero and held there, warming would still continue for several decades (due to the thermal lag of the oceans) until an equilibrium was reached.
    "Secondly, is the level of CO2 in the atmosphere related to the degree or the length of the GW?"
     See answer number two above. Then consider this: The GHG effect means adding CO2 will raise temperatures globally. By how much is a function of climate sensitivity. A doubling of CO2 concentrations from pre-industrial will yield a temperature increase of about 3 degrees C considering short-term effects (less than 100 years). Long-term feedbacks may add another 2-3 degrees C warming on top of that (withing the next several centuries). Barring some form of Carbon Capture Sequestration (CCS), warming is not a transient effect (no more ice sheet advances for the next 30,000 years). A warming/warmer world is here to stay, from the standpoint of human timescales. The Yooper
  45. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    dana1981@76: Stoma is not perfect to detect levels of co2, and ice core samples are not perfect either. There is considerable literature showing that ice cores difuse much more than previously thought. The error bars indicate that recent past co2 could have been as low as 195ppmv or as high as 395ppmb. This is in line with the stoma research.
  46. CO2 lags temperature
    After reading the three years of arguments relating to this question, I still can't form a definitive conclusion in my simple, non-scientific mind. It seems to me that John Cook's rebuttal is an execellent answer but it doesn't go far enough and raises more questions in my mind. It now seems clear that GW is the cause of the increased CO2 in the atmosphere which assisted now by mankind. But the questions are: Firstly, what is the mechanism for the reversal of global warming? Is this when the CO2 levels in the atmosphere reach saturation? Secondly, is the level of CO2 in the atmosphere related to the degree or the length of the GW? These questions seem critical to me since if there is a saturation level then mankind's addition to the levels or to the speed of accumulation of atmospheric CO2 are irrelevant.
    Moderator Response: In the Search field at the top left, type "saturated."
  47. Lindzen and Choi find low climate sensitivity
    Eric, "That is wrong, but also a tangent. Read Trenberth http://journals.ametsoc.org/doi/pdf/10.1175/2008BAMS2634.1 and you will see the other sources of atmospheric heat that are not accounted for in your formula." There is 239 W/m^2 coming in from the Sun but 385 W/m^2 at the surface. This means 146 W/m^2 of the surface power has to come from the atmosphere. Unless there is some other energy source in the system other than the Sun? I've looked at the Trenberth paper. Which part (or page) are you referring to specifically?
  48. Lindzen and Choi find low climate sensitivity
    If you know the post albedo input power and the surface power, the total amount A absorbed by the atmosphere can be calculated by subtracting the post albedo power from the surface power. That is wrong, but also a tangent. Read Trenberth http://journals.ametsoc.org/doi/pdf/10.1175/2008BAMS2634.1 and you will see the other sources of atmospheric heat that are not accounted for in your formula.
  49. Lindzen and Choi find low climate sensitivity
    Eric, "That makes no sense either. The "gain" as described in the paper increases with surface temperature, as shown in 210. "Gain" is 1.0 with no GHG, it is 1.6 with cumulative GHG, thus it is larger with incrementally added GHG. I'm not going to respond any more to statements that "you should have explained better" because frankly I'm in the same boat and the more I try to correct yours, the more likely I will end up making unclear statements myself. " I'm sorry for not being clear. What I mean is the proportional global gain change (i.e. the decrease) is much greater than the tiny little increase in gain as a result of 2xCO2. In other words, the net gain change still decreases.
  50. Lindzen and Choi find low climate sensitivity
    Eric, "co2isnotevil, you say "Everything else only redistributes energy within the system." But in the diagram that you linked to, there is a derived absorption, A, that redistributes energy within the system. If there's no convection or thermals to redistribute heat from the surface to the atmosphere, how can you derive A?" I think A is derived from knowing the weighted averages of the clear and cloudy sky transparent windows of the atmosphere - i.e. how much passes through clear and cloudy sky unabsorbed. If you know the post albedo input power and the surface power, the total amount A absorbed by the atmosphere can be calculated by subtracting the post albedo power from the surface power. This is how much of the surface power is coming from the atmosphere and the difference is the total amount directed out to space. By subtracting this remaining amount from the amount of power that passes through unabsorbed, you can derive how much power absorbed by the atmosphere is directed out to space (385-239 = 146; 0.24 x 385 = 93; 385 - 93 = 292: 292 - 146 = 146; 146 + 93 = 239 leaving = 255K), which is 146 W/m^2 up and 146 W/m^2 down (exactly half up and half down).

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