Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings

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.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

Recent Comments

Prev  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  Next

Comments 100201 to 100250:

  1. 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.
  2. 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
  3. 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
  4. 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.
  5. 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.
  6. 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
  7. 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!
  8. 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.
  9. 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!
  10. 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.
  11. 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?
  12. 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
  13. 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?
  14. 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?
  15. 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.
  16. 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).
  17. 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
  18. 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?
  19. 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.
  20. 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.
  21. 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?
  22. Lindzen and Choi find low climate sensitivity
    Eric, Show us the power in = power out calculations that demonstrate what you're talking about.
  23. 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.
  24. 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.
  25. 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
  26. 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.
  27. 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."
  28. 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?
  29. 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.
  30. 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.
  31. 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).
  32. Lindzen and Choi find low climate sensitivity
    global gain decreases as radiative forcing and surface power increases. 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.
  33. Lindzen and Choi find low climate sensitivity
    Eric, "Also you have not explained what you don't understand in post 210." What specifically in 210?
  34. Lindzen and Choi find low climate sensitivity
    Eric, "In post 5 you said that "gain" of 1.6 takes into account GHG, therefore includes all feedback, so your statement above makes no sense. Also you have not explained what you don't understand in post 210." Sorry, I should have explained this better. The gain of about 1.6 accounts for the cumulative effect of all the individual feedbacks in the climate system - positive or negative. This is not the same as the net feedback operating on the system as a whole, which appears to be negative because the global gain decreases as radiative forcing and surface power increases.
  35. Lindzen and Choi find low climate sensitivity
    the feedback operating on the gain as a whole is appears to be negative... In post 5 you said that "gain" of 1.6 takes into account GHG, therefore includes all feedback, so your statement above makes no sense. Also you have not explained what you don't understand in post 210.
  36. Lindzen and Choi find low climate sensitivity
    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?
  37. Lindzen and Choi find low climate sensitivity
    Eric, In 300, I meant to say "but probably a little less than intrinsic + average gain,"
  38. Lindzen and Choi find low climate sensitivity
    Eric, "The 4W is TOA, so the surface power increase increases from feedback and is greater than 4W." The numbers I presented are the just intrinsic responses. After gain and potential feedback, they would be greater - but probably a little less than intrinsic + gain, because the feedback operating on the gain as a whole is appears to be negative (i.e. as the radiative forcing and surface power increases, the gain decreases and vice versa).
  39. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    A couple of points related to some posts here. 1. Rate of change needs to be considered in determining risk to society. Simply pointing to the total range of past CO2 changes is not sufficient. This also ignores that civilisation has only existed during the Holocene. 2. Climate science is not actually concerned with economics. Economic cost, or a cost benefit analysis of CO2 mitigation, is best left to other experts and should not influence the science. Our job is to define the physical risk posed by altering atmospheric chemistry. 3. I will note however that the cost of mitigation is poorly defined compared to the risks of CO2 increases over the next century. The literature on the economic cost is nowhere near as well developed as the scientific literature, so I would argue that it is the other side of the public debate that is being alarmist- by definition. Doubling atmospheric CO2 in 200 years is a drastic intervention in the climate system. If you claim mitigation is equally as drastic, then point to a peer reviewed body of work that has performed that analysis; i.e. has compared cost versus cost. 4. There is no way that governments would allow climate scientists to openly experiment with the climate system. If Chinese scientists proposed quadrupling atmospheric CO2 (from current concentrations) over 40 years, as a counter intuitive way to stabilize the climate system, and the Chinese government intended on immediately following their advice unilaterally (supposing it were possible), it is doubtful that people would retain their supposed confusion over unsafe until proven safe. The question then becomes, on what scientific basis would the rest of the world let them do it? I do believe that most of the skeptics I have come across would actually be in favor of allowing that course of action, since they believe that such a change in CO2 is unlikely to have a tangible effect on anything. There would be those however, that would suddenly becomes champions of the consensus literature.
  40. Lindzen and Choi find low climate sensitivity
    RW1: "So an increase in 2 W/m^2 (or 4 W/m^2) from additional CO2 (a GHG) would increase the surface power to 392 W/m^2 (or 394) because an additional 2 W/m^2 (or 4) would come from the atmosphere." The 4W is TOA, so the surface power increase increases from feedback and is greater than 4W.
  41. Lindzen and Choi find low climate sensitivity
    Regarding Trentbert's mistakes, he makes several. First, he underestimates the size of the transparent window at about 18%. From line by line simulations for surface to space and surface to cloud to space radiation, weighted by cloud cover, the net transparency is closer to 22%. He completely fails to recognize that of the remaining 78%, half is radiated into space and only half back to the surface. This makes the net transmittance 22% plus half of 78% which is 61%. This means that for each W/m^2 of power that leaves the surface, 61% is radiated into space and 39% is returned to the surface. We can check this by recognizing that the gain from the surface/clouds to space is the reciprocal of the net transmittance, where 1.0/0.61 = 1.6, meaning that it takes 1.6 W/m^2 of radiated surface power for 1 W/m^2 to leave the planet. At an albedo of 0.3 and a solar constant of 341.5 W/m^2, the total power entering the system is 239 W/m^2, corresponding to 255K (from SB). The surface, at an average temperature of 287K, radiates abou 385 W/m^2, where 385/239 = 1.6. BTW, the root of all climate science evil is considering the obvious gain characteristics of atmospheric absorption as feedback, rather than as a component of the open loop gain. When properly treated as gain, the required system feedback is negative. Another mistake is lumping in non radiative components, for example, latent heat and thermals with radiative components. The evaporation/precipitation cycle transfers heat from the equator to the poles and as such is more like an oceanic or atmospheric circulation current, where power goes in as latent heat and comes out as wind, rain and weather. To make the math work out, he lumps in the return path for power arising from evaporated water and thermals as 'back radiation', giving a very misleading picture of the radiation budget. A far better view can be found here. http://www.palisad.com/co2/div2/div2.html Only radiative components are counted in the planets energy balance because energy can only enter and exit the planet's climate system as EM radiation. Everything else only redistributes energy within the system.
  42. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    dana1981 (@76), That WHO study is a good example of seeking out bad news while ignoring good news. Fortunately there are other studies with a more balanced approach that tell us what anyone with a grain of common sense already knows. Falling temperatures are much more dangerous than rising temperatures when we are talking "Climate Change".
  43. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    The stomata "issue" has has its own thread here. It should be noted that there are some issues with the papers in question that have been discussed elsewhere on SS. The "skeptics" continue with their incoherent ramblings.
  44. The Hitchhiker’s Guide to the AGU Fall Meeting
    Skeptical blogs have been getting a little bit hot about other AGU sessions. It's not just about challenging the consensus view but highlighting the fact that the science is still far from settled. UHI and solar spectrum variability come to mind as examples.
  45. The Hitchhiker’s Guide to the AGU Fall Meeting
    This is a great source of information on climate issues. Feel like joining AGW and attend next meeting.
  46. Lindzen and Choi find low climate sensitivity
    The first objection to Lindzen and Choi seems to be that the full coverage, gridded data covering over 1/3 planets surface is insufficient. This criticism is somewhat ironic when all of the temperature reconstructions that show large warming start with very sparse surface measurements. These sparse measurements cover less than 1% of the total surface are and are extrapolated to 100% coverage using homogenization techniques. Similar homogenization techniques were applied to extrapolate the L&C results to cover the whole planet. Extrapolating from the equator to the poles is far more deterministic than extrapolating from the airport at a coastal city to the mountains 100's of miles away. I would suggest that you come up with a more solid 'what the science says' response to this question. If you really want to follow this logic, then everything about 'consensus' climate science is wrong for the same reason. Secondly, it mentions several studies that claim positive feedback. This is the result of confusion between feedback and gain. Consensus climate science assumes unit open loop gain. You can thank Hansen for starting this major FUBAR and Schlesinger for obfuscating the error behind the meaningless units of degrees K per W/m^2, which for all intents and purposes is already quantified by Stefan-Boltzmann! I should point out that from Bode, gain or in this case, sensitivity, must be dimensionless ratios of output power to intput power and only when gain is dimensionless does the very idea of quantifying feedback as positive or negative even make sense. Since the surface is warmer than it would be otherwise. The closed loop gain is clearly greater than one. Assuming unit open loop gain, a matching result can only occur when there's about 12% positive feedback. If instead of assuming unit open loop gain, we use a value of about 1.2, 12% negative feedback is required. It turns out that the 1.2 open loop gain is not arbitrary and is measurable. In this case, the system gain is the ratio between emitted surface power and total incident power and is about 1.12, compared to the surface gain of about 1.6. Albedo can't just be subtracted out when determining the system response since albedo variability is part of the control mechanism.
  47. Lindzen and Choi find low climate sensitivity
    Eric, In my first example from Post 295, that's 238 from the Sun and 154 W/m^2 from the atmosphere (+2 W/m^2 from the atmosphere).
  48. Lindzen and Choi find low climate sensitivity
    Eric, Look at this way: At a temperature of about 288K, the surface power is about 390 W/m^2. If about 238 W/m^2 is from the Sun, then the remaining 152 W/m^2 has to come from GHGs and clouds in the atmosphere, right? So an increase in 2 W/m^2 (or 4 W/m^2) from additional CO2 (a GHG) would increase the surface power to 392 W/m^2 (or 394) because an additional 2 W/m^2 (or 4) would come from the atmosphere. The original gain is 1.638 (390/238). The new gain as a result of increased CO is 1.647 (392/238), so yes higher GHG absorption does increase the overall gain a little but not very much - only by about 0.5-1%. Also, if the solar power increases 2 W/m^2, the surface power also increases to 392 W/m^2 (this time 240 from the Sun; 152 from the atmosphere). The new gain is 1.633 (392/240) - only about 0.3% less than the original gain. So yes, there is a very small increase in the gain from increased GHG concentration, but it is no where near 8 or 4 and is still extremely close to about 1.6. More importantly, do you see how this shows that power from the Sun and power from CO2 is the same as far as the surface power flux is concerned? Whether the additional power is from the Sun or CO2, the net effect at the surface is proportionally the same.
  49. Do high levels of CO2 in the past contradict the warming effect of CO2?
    #20: Consider looking around SkS, you might learn something See this thread on the non-existent lag question. If you have further questions about the lack of lag, use that thread. See this website for thorough debunking of your 'swindle,' which is a swindle of its own. To state the obvious, facts make a better argument.
  50. Lindzen and Choi find low climate sensitivity
    RW1 asked if I agreed that power from the Sun was the same as power from CO2, and whether or not both are "forcing" the surface. You've asked that over and over, please stop asking. The answer is no, those are unscientific terms. Here's a (somewhat) more scientific question: Does the (total or increase in) power from the sun have the same "gain" (as defined in the link in 150) as the (total or increase in) power from CO2? Answer: No, the paper is wrong. Explanation: reread 210, and ask questions about 210 if you don't understand it.

Prev  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  Next


The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us