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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 100151 to 100200:

  1. 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.
  2. 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?
  3. 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.
  4. 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.
  5. 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?
  6. Lindzen and Choi find low climate sensitivity
    Eric, In 300, I meant to say "but probably a little less than intrinsic + average gain,"
  7. 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).
  8. 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.
  9. 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.
  10. 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.
  11. 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".
  12. 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.
  13. 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.
  14. 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.
  15. 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.
  16. 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).
  17. 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.
  18. 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.
  19. 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.
  20. Do high levels of CO2 in the past contradict the warming effect of CO2?
    As I have only recently discovered this site and not spent much time searching for the answer to my question, perhaps someone can enlighten me. It seems to me that there has been no response on this website to the critical argument put forward in "The Great Global Warming Swindle". This was that the build up of CO2 in the atmosphere is a product of global warming and not the cause. The coincidence of the fluctuations in CO2 and GW was the claim made in "An Inconvenient Truth" and was illustrated by the huge stage-encompassing graph showing their correspondence. What the GGWS documentary pointed out the graph didn't take into acount the 800 year lag, which was swallowed by the huge time scale of the graph. To state the obvious, if CO2 is the product of GW then the world is embarking on probably the most expensive mistake in history.
  21. Lindzen and Choi find low climate sensitivity
    e is emissivity (see formula in 210)
  22. Lindzen and Choi find low climate sensitivity
    When you say "not at its current operating point", that means the gain is dependent on operating point which means it increases as GHG gas concentrations increase.
  23. Lindzen and Choi find low climate sensitivity
    Eric, "(continued), Do you agree that the reason "gain" increases is because e decreases with increased CO2? Do you understand then that for "gain" as you've defined it, that 1 W/m^2 of solar forcing increase is not the same as 1 W/m^2 of equivalent CO2 forcing increase?" What is "e"?
  24. Lindzen and Choi find low climate sensitivity
    Eric, "RW1, in #263 you asked for an explanation of why "gain" from the website you linked to isn't constant. KR provided an explanation in #210, that temperature increases to compensate for decreasing emissivity due to GHGs. He pointed out that with no GHG, "gain" is 1.0 Q1: Do you agree or disagree with that statement?" Yes, but only if there were no clouds too. In other words for the gain to be 1, there would need to be no GHGs and no clouds in the atmosphere. "Your answer in #213 was "I know the gain isn't a constant, but an average. It fluctuates somewhat, but the range of fluctuation doesn't go anywhere near 8 (or 4) that is necessary to amplify 2xCO2 to 3 degrees C." As KR pointed out, "gain" increases with increasing GHG concentration, it does not just fluctuate in some non-specific way. Q2: Do you agree that "gain" increases with GHG concentration?" No, not at its current operating point. The gain is simply the current ratio of surface power to post albedo solar power. Now, the surface power itself would increase with higher GHG concentration, but that's because the radiative forcing from the GHGs would also increase the power flux at the surface. This is why I asked if you agreed that power from the Sun was the same as power from CO2, and whether or not both are "forcing" the surface.
  25. It's the sun
    First, "relatively quiet behavior" is not necessarily cooling, the (cooling) low cloud coverage diverged from the higher GCR (quiet sun) cosmic-rays-and-global-warming.htm The quiet behavior (and increased GCR) can certainly change the weather in some cases (e.g. increased blocking). Second, the cooling would not be instant due to thermal inertia (i.e. the ocean is storing the cooling)
  26. It's Pacific Decadal Oscillation
    Mouncounter The article said : "Until about 1960, measurements by scientists showed that the brightness and warmth of the sun, as seen from the Earth, was increasing. Over the same period temperature measurements of the air and sea showed that the Earth was gradually warming. It was not surprising therefore for most scientists to put two and two together and assume that it was the warming sun that was increasing the temperature of our planet." And they might be right. The problem is confusing the fast warming from 1978 with the long slow warming from 1880 to 2010. Both have happened and proving a single cause can't have caused both is part of the divide and conquer strategy. The long slow overall warming since the end of the Maunder minimum is in my opinion caused by increasing solar activity and positive feedback which can take centuries. It is a long integration and rapid change like that between 1978 and 1998 is not what it does. The rapid [1.2 ° C per century ] warming between 1978 and 1998 is certainly not because of solar increase. [nor CO2 IMHO] The ADO and PDO and a huge El Nino were conveniently positive during this period and in my opinion caused most of the warming . The climate is complicated and proving that neither solar increase or ocean currents could have caused everything is not a reason to exclude them as part of the answer. I am unsure exactly which argument is the "Climate Time Lag" one. Please re-post the link. Archi said supposedly quoting me: "For isntance [sic], there is no evidence AFAIK [???] that the PDO and the LIA are directly related, therefore trying to link the two in some sort of "grand unified denier theory" is off-topic. 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.
    Moderator Response: It's past time for you to learn to use the Search field at the top left.
  27. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    The second sentence in my last paragraph should read "...than *just* CO2". For more details see the link provided by chris in #75.
  28. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    anastrophe - you have to learn how science works before claiming "i want science". Scientists speak the language of probabilities, not absolutes. Scientists always use worlds like "likely" and "probable" and "possible". To claim that's not science simply reveals that you don't understand science. As for current harm, the WHO states "The global warming that has occurred since the 1970s was causing over 140,000 excess deaths annually by the year 2004." Now, I'm sure you'll call this an "anecdote" just like you'll call any evidence you don't want to believe an "anecdote", so I'm not going to waste time giving you more evidence. But more importantly, we're not worried about current temperatures. If the planet stopped warming right now, we'd be fine. We're worried about the potential for catastrophic climate change if the planet warms another couple of degrees. Your argument, aside from being wrong, is a strawman. From Peru #69 - the short answer is that plant stomata are an indirect and thus imperfect measurement of atmospheric CO2. More factors impact stomatal density than must CO2. That's why climate scientists use air trapped in ice cores to *directly* measure past CO2 levels, rather than stomata.
  29. Lindzen and Choi find low climate sensitivity
    (continued), Do you agree that the reason "gain" increases is because e decreases with increased CO2? Do you understand then that for "gain" as you've defined it, that 1 W/m^2 of solar forcing increase is not the same as 1 W/m^2 of equivalent CO2 forcing increase?
  30. Lindzen and Choi find low climate sensitivity
    RW1, in #263 you asked for an explanation of why "gain" from the website you linked to isn't constant. KR provided an explanation in #210, that temperature increases to compensate for decreasing emissivity due to GHGs. He pointed out that with no GHG, "gain" is 1.0 Q1: Do you agree or disagree with that statement? Your answer in #213 was "I know the gain isn't a constant, but an average. It fluctuates somewhat, but the range of fluctuation doesn't go anywhere near 8 (or 4) that is necessary to amplify 2xCO2 to 3 degrees C." As KR pointed out, "gain" increases with increasing GHG concentration, it does not just fluctuate in some non-specific way. Q2: Do you agree that "gain" increases with GHG concentration?
  31. It's the sun
    Continuing from a comment here. "Solar variation did not cause the 78 – 98 warming but it can cause the 1880 to 2010 trend" Barring the obvious fact that 78-98 are contained in 1880-2010, there is no evidence for this 'solar cause'. Sunspot numbers correlate well with satellite measures of solar irradiance and the reconstructions of solar output don't support it. If anything, the sun's relatively quiet behavior in recent years should have a cooling effect; yet we know that 2000-2009 was one of the hottest 10 year period in the last 6 decades.
  32. Lindzen and Choi find low climate sensitivity
    muoncounter, "Its hard to say if anyone is interested in the continuing lecture series this thread has become. The questions and counter-arguments started at comment #7, but they were evaded a number of times." Please point to something specific you don't feel I addressed and I will respond to it (I'm serious). "I would ask that you refrain from suggesting to interested parties that they shouldn't participate in what you've clearly come to think of as 'your' thread. Unless you're paying the rent here, you have no say over who comes and goes." That's not really what I meant, but I get your point. Fair enough. "I suppose all I am really mildly curious about is whether the 'doubling of CO2' paper linked below the comment box here is your work as that came out with a higher sensitivity -- 1 deg C per doubling -- than you currently claim. No. I've never even heard of the paper or the author.
  33. It's Pacific Decadal Oscillation
    #35: "...impossible to post coherent arguments" There's an obvious response to that, but in the spirit of the season, I'll let it slide. I will suggest that you would gain a morsel of credibility if you stopped using the word 'catastrophe' every few sentences. But here's an example of how to stay on topic: Responding to your comment on solar variation here. Please follow the link. asteel: "grand unified denier theory" -- I love it!
  34. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    From Peru at 08:56 AM on 27 December, 2010 Peru, from a quick perusal of your link it seems that Dave Middleton is posting much the same stuff that he posted here under the topic Plant stomata show higher and more variable CO2 levels last summer. His arguments were not very convincing then and you might want to consider whether he has addressed the criticism from posters here, in his new post that you linked to.
  35. Lindzen and Choi find low climate sensitivity
    #279: "the specific counter-argument presented that I have failed to address" Its hard to say if anyone is interested in the continuing lecture series this thread has become. The questions and counter-arguments started at comment #7, but they were evaded a number of times. I would ask that you refrain from suggesting to interested parties that they shouldn't participate in what you've clearly come to think of as 'your' thread. Unless you're paying the rent here, you have no say over who comes and goes. I suppose all I am really mildly curious about is whether the 'doubling of CO2' paper linked below the comment box here is your work as that came out with a higher sensitivity -- 1 deg C per doubling -- than you currently claim.
  36. Lindzen and Choi find low climate sensitivity
    michael, "The extra power from the sun will be distributed the same as the sun's power: highest at the equator, during the summer and only increasing during the day. The power from CO2 will be distributed differently: all seasons, at night as well as day and at all latitudes. Since the forcing is distributed differently, the effect is different. This difference has been measured. The night warms more than the day, the winter has warmed more than the summer and nights have increased more than days. All this information has been discussed on this site in the last month. Most of this is discussed in the Scientific Guide to Global Warming linked on the top of this page. Give it a good read and you will know more of the background information." The solar forcing numbers I've used are global averages, which automatically include all of things you mention. The effect is proportionally the same, because the only source of energy in the climate system is from the Sun (plus a tiny bit of heat energy emitted from the interior of the earth). Beyond that, everything is about heat fluxes and the rate at which incoming power is delayed from leaving the planet due to the presence of GHGs and clouds in the atmosphere.
  37. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    "Although, I suppose you shouldn't use anything you have that uses LEDs or integrated circuits if you can't tolerate guessing." Or godly-dice-rolling tunneling diodes ...
  38. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    " 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". a heatwave? why, that's not weather, that's clear and present proof of global warming!" 1. heavy snowfall is not a reliable indicator of a colder winter. Nor'easters, for instance, get their moisture while traveling across the atlantic offshore of the southern US. When that portion of the atlantic warms, more moisture is evaporated into the storm system, which then dumps more snow when it hits the colder air inland and northward. 2. Parts of Europe during this cold spell have been having century events. The Russian heat wave, on the other hand, was unprecedented in the last 1,000 years, according to Russian scientists who have made proxy reconstructions of past climate conditions there. 3. Thus far December has seen extremely warm weather in the arctic. The push of warm air north has led to arctic air infiltrading part of Europe and part of North America. 4. As you can see, much of North America (and the US) has been warmer than normal, not colder than normal. Compare this to the fact that the 2010 meteorological year (Dec 2009-Nov 2010) has been the warmest on record, globally. 5. About twice as many record highs have been broken than record lows in the last few years. None of them individually point to global warming. The trend towards more high than low records being broken is however consistent with global warming, and inconsistent with global cooling.
    Moderator Response: [Daniel Bailey] Fixed text.
  39. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    #67: "show that harm has occurred." Consider looking around a bit before coming to what may be pre-conceived conclusions. Try the Extreme weather thread or Its freaking cold, for starters. "i want science, not guessing. " You may have heard that large portions of modern science are entirely concerned with the study of increasing and decreasing probabilities of various events. If you choose to call that 'guessing', that's your privilege. Although, I suppose you shouldn't use anything you have that uses LEDs or integrated circuits if you can't tolerate guessing.
  40. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    Sorry, the paper's presumably not nonsense, but the WUWT post interpreting them is. Has WUWT ever been right about *any* paper they claim proves portions of climate science to be wrong?
  41. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    "This is not the tipical nonsensical stuff found in blogs like WattsUpWithThat. " Actually, yes, it is, and a couple of the more knowledgeable denialists over there point out why. Ferdinand Engelbeen's response, for instance.
  42. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    What about this post in WUWT: CO2: Ice Cores vs. Plant Stomata http://wattsupwiththat.com/2010/12/26/co2-ice-cores-vs-plant-stomata/ It states that: -Plant stomata suggest that the pre-industrial CO2 levels were commonly in the 360 to 390ppmv range. (source: Kouwenberg, 2004. APPLICATION OF CONIFER NEEDLES IN THE RECONSTRUCTION OF HOLOCENE CO2 LEVELS. PhD Thesis. Laboratory of Palaeobotany and Palynology, University of Utrecht.) -Plant stomata data show much greater variability of atmospheric CO2 over the last 1,000 years than the ice cores and that CO2 levels have often been between 300 and 340ppmv over the last millennium, including a 120ppmv rise from the late 12th Century through the mid 14th Century. (source: Kouwenberg et al., 2005." Atmospheric CO2 fluctuations during the last millennium reconstructed by stomatal frequency analysis of Tsuga heterophylla needles". GEOLOGY, January 2005.) -A recent study (Van Hoof et al., 2005) demonstrated that the ice core CO2 data essentially represent a low-frequency, century to multi-century moving average of past atmospheric CO2 levels.The stomata data routinely show that atmospheric CO2 levels were higher than the ice cores do. (source:Van Hoof et al., 2005. Atmospheric CO2 during the 13th century AD: reconciliation of data from ice core measurements and stomatal frequency analysis. Tellus (2005), 57B, 351–355.) This is not the tipical nonsensical stuff found in blogs like WattsUpWithThat. John Cook, what do you think about these studies that show high levels of CO2 in recent past? (By the way it seems like an interesting material for a post)
  43. Lindzen and Choi find low climate sensitivity
    RW1, The extra power from the sun will be distributed the same as the sun's power: highest at the equator, during the summer and only increasing during the day. The power from CO2 will be distributed differently: all seasons, at night as well as day and at all latitudes. Since the forcing is distributed differently, the effect is different. This difference has been measured. The night warms more than the day, the winter has warmed more than the summer and nights have increased more than days. All this information has been discussed on this site in the last month. Most of this is discussed in the Scientific Guide to Global Warming linked on the top of this page. Give it a good read and you will know more of the background information.
  44. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    "rising CO2 is isn't safe" - should be "rising CO2 isn't safe".
  45. Is it safe to double atmospheric Carbon Dioxide over a 200 year period?
    @archiesteel: um, that's not how science works. science needs to show that recent extreme weather events have been made worse. so far, if it seems to support the AGW theory, then AGW proponents claim that weather events have to do with changing climate. if they don't support the AGW theory, AGW proponents claim 'that's weather, not climate'. 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". a heatwave? why, that's not weather, that's clear and present proof of global warming! it's for those claiming that there is harm to show that harm has occurred. just like this article - which claims that it's about showing that rising CO2 is isn't safe, when all it addresses is that CO2 has risen. the sources in intermediate seem to all be talking about 'expected' harm. a typical example iis http://www.sciencemag.org/content/323/5913/447.short - "are the likely cause". i want science, not guessing.
  46. Lindzen and Choi find low climate sensitivity
    scaddenp, "Of course they can. The forcing term is global annual average. The energy flux (NOT power - please note that this term is normally used in context of energy transformation) produces the same temperature rise without feedbacks." This is what I'm referring to - the intrinsic response only. And what triggers the feedbacks? The intrinsic temperature rise - which you just said was the same for solar power and power from CO2. "However, for considering feedbacks, the energy flux is different spatially, temporally, and spectrally between solar and GHG (and aerosols and albedo if it comes to that)." Why? A watt is a watt - a joule is a joule, is it not? Explain to me how the surface, whose temperature is directly tied to the total power flux via Stefan-Boltzman, is going to 'know' the difference from increased power from Sun or CO2? Even further, even if it were to somehow 'know' the difference, for what physical reason would it respond differently to the same amount of heat increase? (*Please understand that this is not the same question as additional power from CO2 on top of all the current solar power. I think many in this thread are confusing the two, and from that, deriving that I somehow don't understand this distinction.)
  47. Lindzen and Choi find low climate sensitivity
    As an off-topic note, it would be nice to be able to vote (or at least register our agreement/disagreement) on comments. Some sort of "real ID" registration would also help weed out sockpuppet accounts (not aiming this at anyone in particular, mind you). Skeptical Science 2.0, anyone? ;-)
  48. Lindzen and Choi find low climate sensitivity
    @RW1: sure, you can start by responding to chris at #222. I'm also curious to see if you will acknowledge you were wrong when you said: "If this is true, then power from the Sun and power from CO2 cannot both be expressed in W/m^2 as they are." scaddenp and I both revealed your misconceptions about what the W/m² figure means. Will you admit you were wrong about this, and thus about the 4 W/m² having to be cut in half to calculate sensitivity? A simple yes or no will suffice.
  49. Lindzen and Choi find low climate sensitivity
    "If this is true, then power from the Sun and power from CO2 cannot both be expressed in W/m^2 as they are." Of course they can. The forcing term is global annual average. The energy flux (NOT power - please note that this term is normally used in context of energy transformation) produces the same temperature rise without feedbacks. See the chapter in the IPCC on why you calculate forcings in this way and evidence that it can used for arithmetic. However, for considering feedbacks, the energy flux is different spatially, temporally, and spectrally between solar and GHG (and aerosols and albedo if it comes to that).
  50. Lindzen and Choi find low climate sensitivity
    archiesteel, When someone offers a cogent counter-argument and you don't respond, then you have been successfully rebutted. I'm hardly the first one to note this here, either. I know I have missed a few things and haven't responded to everything. Again, I stated that in the middle of the thread somewhere. Please point me to the specific counter-argument presented that I have failed to address and I'll respond to it.

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