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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 64451 to 64500:

  1. Hockey Stick Own Goal
    "the trend in temperatures since 1980 is approx 0.12 degrees C per decade"

    Tamino's graph shows a slightly higher trend, as do the composite surface reconstructions put together by Ned back in July 2010.



    Northern hemisphere 30 year trends are 2-3 times these rates.

    "average standard deviation of the running 30 year interval over the instrumental period to 1979 is 0.103"

    Do you mean the satellite record since 1979? Or the surface record up to 1979; if so why stop in 1979? In either case, its a noisy signal; hence the rationale (as I read it) for Tamino's filtering process rather than a purely statistical trend removal.
  2. Hockey Stick Own Goal
    Muoncounter @124:

    Marcus: "is it fair to say that man-made forcings are now great enough to entirely swamp all natural forcings?"

    Muoncounter: "I think that is more than fair ..."

    To put it into context, the trend in temperatures since 1980 is approx 0.12 degrees C per decade (0.116 where underline indicates a recurring integer). For comparison, the average standard deviation of the running 30 year interval over the instrumental period to 1979 is 0.103, so temperature increase per annum is just over a tenth of the normal annual fluctuation in global mean temperatures.

    The fluctuation in regional mean temperatures is, of course, much larger so that at a regional level, annual variation is far more significant.
  3. Climate sensitivity is low
    I tried. I'm going to get to bottom of this. I'll be back when I know and can show the proof.
  4. Climate sensitivity is low
    RW1 - The reduction in the atmospheric window represents only a small portion of the 3.7 W/m^2, as Tom Curtis said. Sorry I don't have exact numbers, but (as I have a day job) I haven't put in a request for the HITRAN data.

    If you look at the actual spectra of top of atmosphere (TOA) emissions, you will see the GHG blocked bands:



    The baseline of around 225K (around 650 microns) in the first graph represents the lapse-rate cooled greenhouse gas emission at the altitude where the IR can actually reach space without being intercepted by more GHG's. The higher this goes, the cooler the gases, the lower the temperature for emission, the lower the bottom of that curve. And hence the lower the integrated power over the entire spectra.

    My question to you is: Why does it matter? What's the issue with the 'window' versus lowest temperature of fully intercepted bands? I'm genuinely curious, especially since you've been poking at that for some days now - why is the percentage involved in 'window' narrowing important relative to the total integrated power blocked by a doubling of CO2? Do you have an argument based upon 'window' size?

    The reason I ask is because I don't see why the distribution would be an issue - the total energy imbalance (change in emitted energy with doubled CO2) is what is important as a forcing, rather than exact spectral distribution (and I say that as someone who works with spectrometers all the time!).
  5. PMEL Carbon Program: a new resource
    Rob Painting... saying that it is my opinion that 'XYZ' is more likely caused by a major non-anthropogenic factor than a minor anthropogenic factor is not going out on a limb.

    It is like hearing hoof beats at a racetrack and looking for horses - you are looking for zebras...

    Please detail the critical flaw in my reasoning - as I have done for you.

    Note that I did not say that upwelling causes total ocean pH decrease (that would be a strawman) - I stated that local upwelling is the direct cause of the ill effects such as low pH stressed shellfish.

    I also went on to say that local CO2 concentration is a function of water temperature, with more CO2 in colder water.

    Also please take a look at the the change in CO2 for the CLIVAR Repeat Section P06 I think it will be revealing...
  6. Climate sensitivity is low
    Here is a question:

    If the 3.7 W/m^2 does not represent the reduction in the atmospheric window, then what is the reduction in the atmospheric window from 2xCO2?
  7. A detailed look at galactic cosmic rays
    DB, (or should I call you Spoon Boy?)
    Do not try to bend the spoon fix the italics tag — that's impossible. Instead, only try to realize the truth: there is no spoon italics tag.
    Moderator Response: [DB] Yes, Obi-Wan; this Padawan realized his error, adapted, improvised and overcame. Move along, go about your business now.
  8. Climate sensitivity is low
    Tom Curtis (RE: 125),

    "The combination of these two effects will reduce the total energy leaving the atmosphere by 3.7 w/m^2"

    Wonderful. Now please provide me the documentation for this. What you don't seem to understand is I already know this is what is being claimed - I don't need to you to tell me it's true.
  9. Climate sensitivity is low
    So the 3.7 W/m^2 does not represent the reduction in the atmospheric window, nor does it represent the incremental absorption?
  10. How We Know Recent Global Warming Is Not Natural
    Poptech@100
    "make sure to read my rebuttal to his post which they do not want you to read."

    What are you talking about? fixtures23 is free to read whatever he likes. No one here can stop him though they may advise against it. As long as you post on topic and in a civil manner your comments will not be deleted.
  11. 2nd law of thermodynamics contradicts greenhouse theory
    DM,

    You should be aware that friend damorbel is on record against heat flow: "first off heat doesn't flow'; only fluids flow."

    A couple of hundred comments later comes "I have made a number of relevant arguments about the direction of heat transfer (hotter to colder)".

    Are you willing to spend another hundred or more comments re-drawing the distinction between 'flow' vs. 'transfer'?
  12. Hockey Stick Own Goal
    Marcus,

    "at least 1 major volcanic eruption"

    If you're referring to Iceland's Eyjafjallajökull volcano, my understanding was that it wasn't a major climate-mover. Lots of dust, but not enough oomph (it was VEI 4, compared to Pinatubo's VEI 6 -- a logarithmic scale) to put it into the stratosphere.

    "is it fair to say that man-made forcings are now great enough to entirely swamp all natural forcings?"

    I think that is more than fair; a result elegantly shown by Tamino's analysis removing short term factors to find the core trend.

    .

    Tamino also shows separate graphs for volcanic, solar and MEI fluctuations removed from the temperature signal. And the forcing that is left driving the uptrend is ... you guessed it!
  13. How We Know Recent Global Warming Is Not Natural
    Poptech, fixtures23 has all the look of a bot. Do you agree with the position of fixtures23 regarding the science?
  14. Climate sensitivity is low
    Well, I am used to the more usual definition of power as rate of energy conversion. The GW usage just sounds so strange when used instead of energy flux. Mix it in with amplifier analogues and its a real recipe for confusion. There is a lot to said for accuracy ( though I know I am pot calling kettle black at times). On other hand, met anyone not acquainted with GW using power in this peculiar way when discussing radiative physics?
  15. Philippe Chantreau at 12:28 PM on 26 February 2011
    Meet The Denominator
    "I went through each paper to see if it supported my position." Either that is false or your reading comprehension fails to accomplish that goal.

    You acknowledged earlier that the Mavromichalaki paper did not support your position. Perhaps you should have said each paper but one; or perhaps most papers? How can we know? Trust you? When you just threw that one inaccurate statement for the sake of argument?
  16. Motl-ey Cruel
    "My suspicion is that Lubos Motl has a political ax to grind" ...

    Well, as a self-styled conservative physicist, I'd say it's a good bet. "conservative" relates to his politics, not to his physics - he's a string theorist, after all! :)
  17. Hockey Stick Own Goal
    Muon @ 121. It's true that 2010 is tied has hottest year ever recorded, yet it had a culmination of negative natural forcings (at least 1 major volcanic eruption, below average sun-spot number & a La Nina event) that should have made it *colder* than 2008. So, on that basis, is it fair to say that man-made forcings are now great enough to entirely swamp all natural forcings? Sorry if this is OT, but I'd be interested in your thoughts on this!
  18. CO2 limits will harm the economy
    Thingadonta, far more solar energy reaches the earth every year than can be used by our civilization. Therefore talking about conservation of energy is irrelevant.

    The cost of energy is important, and the direct cost of alternative energy is currently greater than the direct cost energy from fossil fuels. However, the indirect costs of fossil fuels are very large. Our society does not seem to care, because those costs will be paid for primarily by future generations rather than by us. Ignoring those direct costs will not cause future generations to thank us.
  19. CO2 limits will harm the economy
    Energy cannot be creatd or destroyed, except in the minds of those who advocate alternative energies.

    If something produces less energy than something else, it's going to cost more money to use it. It's not rocket science, and rockets will not get to the moon using wind energy.
  20. Climate sensitivity is low
    RickG @123, scaddnp @125, being fair to RW1, power is just energy over time, and the Watt is a unit of power, not of energy. For convenience, when measuring the energy balance of the Earth, climatologists use the unit of watts/meter^2 rather than joules/second meter^2, which would be more formally correct when talking about energy.

    Talking about the "power that escapes the atmosphere" rather than the "energy that escapes the atmosphere" would be peculiar; but talking about the "power that is transmitted" or the "power that passes through" the atmosphere is not, so I don't see your point.
  21. Dikran Marsupial at 08:24 AM on 26 February 2011
    2nd law of thermodynamics contradicts greenhouse theory
    damorbel@376 O.K. so you agree that heat energy can flow from a cooler body to a warmer object? In this case heat energy does flow from the cooler shell to the warmer inner body, although there is a greater flow of heat in the other direction, and so the second law of thermodynamics isn't broken.

    Now put an identical heater in both bodies, each supplying the same amount of heat energy - just sufficient for the first body to maintain its temperature. What happens to the temperature of the inner body within the shell?
  22. Dispelling two myths about the tropospheric hot spot
    "It would be nice to have data up until and including 2010."

    Will generate these this weekend.

    "One can see the polar amplification (a predicted consequence of a warming planet) over the Arctic nicely in most datasets."

    Yes.

    And the stratospheric cooling, and even the shape of the stratospheric cooling seems to verify.

    But the hot spot, not so much.
  23. It warmed before 1940 when CO2 was low
    I agree with barry in #4 that "the 1800s" has been confused with "the 18th Century."

    His post was almost a year ago, and there have been responses in the interim ... why hasn't this single-character edit been effected?
    Moderator Response: [Daniel Bailey] Until lately, lack of manpower. I'll see about getting this one fixed. Thanks for noticing it & bringing it to our attention!
  24. macwithoutfries at 07:53 AM on 26 February 2011
    Prudent Risk
    Very interesting post - but I understand that all those studies not only exclude slower-acting feedbacks such as melting ice but also exclude any feedback on permafrost and any methane that is currently locked - wouldn't that be the real 'worst case scenario' which should be also taken into account? Since I know a number of stupid people that will certainly claim that a temperature increase around 0.3 C in this or in the next decade (instead of around 0.2) would also somehow mean that the AGW theory is wrong ...
  25. CO2 limits will harm the economy
    Berenyi:
    What is the value of preserving the land in Bangladesh? With only 2 meters of sea level rise 100,000,000 people will be refugees from that part of the world alone. Not to mention all the other major cities around the world that will be inundated. What is the benefit of maintaining those cities versus the cost of building new cities further inland? These are clear economic benefits that have not even been added to most of the analysis cited above, the recent sea level estimates were not available. The infrastructure alone is worth trillions of dollars in the USA.
  26. actually thoughtful at 07:37 AM on 26 February 2011
    Hockey Stick Own Goal
    Protestant - I can't say that I came around to your point of view. But I do find the divergence from Proxies problem to be too quickly 'splained away and never discussed again.

    I can say your posts made me think about my position, and I appreciate that.

    I thought the moderators were too hard on you, but to their credit, they also kept a tight reign on the pro-AGW posters.

    Thanks for posting, and sticking to your guns.

    I do think it is intellectually unfair to say "a large MWP spike COULD be the influence of internal variability" - and then offer up no coherent theory. It really, truly begs the question: What DID do the warming?

    One avenue your posts directed my brain to was the problem of confirmation bias. I have looked at the evidence and concluded climate science explains the climate (with a few caveats - but on a macro scale the science seems robust). And given that AGW is the name for the climate science explanation of our current situation - I am a "pro-AGW" person. And when new evidence comes in, I apply more scrutiny if it seems to contradict AGW, and less if it seems to confirm it.

    When I begin to think I have a problem here - as your posts did - I fall back to this. Where is the competing theory that explains all the data and evidence, and does not appeal unduly to unknown phenomena? That is where most of the objections to AGW die down.

    And finally, in regard to your claim that un-fiddled data shows .5C, rather than .8C warming. I could accept that at face value and still be very, very worried. Rolling that forward - that would mean a sea level rise in this century of 1-2 meters, instead of 2-4. That would mean 2.5C warming instead of 4C. We are seeing HUGE effects at .5 or .8 and the multi-decadal trend is getting worse. And we are 40 years of warming into your 60 year cycle. When/where and how soon is that cooling coming? Because logic tells us when the sun "wakes up" and we switch from La Nina to El Nino - the experienced warming is going to get worse, not better.
  27. Prudent Risk
    We cannot keep letting the ‘skeptics’ get away scot-free with such tactics. I suggest that we, too, should write to the US Congress, drawing their attention to the flaws in the arguments advanced by the ‘Prudent Path’ group by giving them a copy of this post.

    If the covering letter were to be signed by as many heavy-weight scientists as we can muster, it would obviously raise its profile. I think that we could get more out of this exercise if we offered the opportunity for them to raise any queries they have regarding the science contained in the post. If we explained that because there could be other members of Congress that might have similar points of concern, all queries will be in open forum, i.e. open to view by all, at .... (‘Congress Queries’? – only posts by members of Congress with replies by selected scientists.)

    These people are politicians, so they will be acutely aware that the media may well quote from this page in order to demonstrate an individual’s level of concern on the subject of Climate Change, a subject that will obviously be somewhere near the top of the agenda in the next round of elections to Congress. They would be foolish to appear uninterested, so will probably want to raise a question or two, if only for appearances. However, in raising any questions, they will have to make sure they understand them in case they get called to explain their concerns. Who knows, they might even come to see that ‘business as usual’ is not a realistic option! If we could raise enough interest now, it might even be a good media story before we get any replies. That would make the public turn to the ‘Skeptical Science’ website in order to check up on their member of Congress.

    Pity this ‘Prudent Path’ group didn’t write to all senior politicians everywhere – we could really spread the word then!
  28. 2nd law of thermodynamics contradicts greenhouse theory
    Re 375 Dikran Marsupial you wrote:-
    "how does the first body know that it is radiating to 0K".

    It doesn't 'know' that. A body radiates only according to its temperature. What is does 'know' (if you can talk of bodies 'knowing' anything) is how many photons it receives.

    Your example of a body 'surrounded by a black shell at 272K 1mm away' means that the inside body receives almost as much energy from the shell as it loses. This imbalance means the inner body cools slowly to 272K.

    You wrote:-
    "and know to emit fewer photons?"

    The first body doesn't emit 'fewer photons'; the photons it emits get progressively less enegetic as it cools, according to the formula for photon energy 'E',

    E = hv
    where 'h' is Planck's constant and 'v' is the frequency.

    The number of photons remains the same.
  29. A detailed look at galactic cosmic rays
    Tom,

    "increased GCMs will increase cloud albedo by a small amount. It is obviously not a large amount because, if it were, the effect would be very obvious in the temperature record "

    Thanks. But that albedo increase may well be below any reliably detectable threshold. It would seem to be a second-order mechanism to the whole Svensmark idea, which has thus far eluded reliable detection on its own.

    It was really the low solar-lack of volcano activity link that made me wonder what I had missed way back when in my 'shake and bake' class.

    Editors: an unclosed italics tag seems to have infected this thread, immediately after Fig 4.
    Moderator Response: [Daniel Bailey] I took a look at it; the error is in the html editing window. It's like The Matrix, raw code. Gonna take a bigger boat than I have to fix...
  30. Climate sensitivity is low
    " And why do you use the word "power"? What is power?". It's the surest sign that you are dealing with someone who has got their education from George White. This incorrect usage has been pointed out to RW1 before.
  31. Dikran Marsupial at 06:23 AM on 26 February 2011
    2nd law of thermodynamics contradicts greenhouse theory
    damobel how does the first body know that it is radiating to 0K and know to emit fewer photons?

    BTW, this was the first stage in the thought experiment, lets not get ahead of ourselves, if we take it in small steps it will be easier to find out where our views diverge. The point of the examples is to find the point of divergence, which is the first step in determining which position is correct.
  32. Hockey Stick Own Goal
    ranyl,

    Welcome to SkS. You've put a lot into one post; its usually better for everyone (and easier to follow) if you stay topic-specific and break a long post into several smaller ones. Use the Search function to browse the existing threads, which are organized by skeptic 'argument' and comment on the appropriate thread.

    One thing jumps out in a quick scan of your post: "So if 2010 and its weather was a cold year, what is a warm year going to be like?"

    Most put 2010 as tied for the warmest year on record.
    For 2010, the combined global land and ocean surface temperature tied with 2005 as the warmest such period on record, at 0.62°C (1.12°F) above the 20th century average of 13.9°C (57.0°F).

    What a warm year was like can be found in threads such as Extreme weather. Not a pretty picture.

    There's a lot to learn here, because so many posters follow the practice of substantiating their points with references to scientific research. And avoid such declarative statements like 'everybody knows it's warming because ... '.
  33. 2nd law of thermodynamics contradicts greenhouse theory
    Re 373 Dikran Marsupial, you wrote:-

    "Which object will cool faster and why?"

    The first because it radiates to a fixed 0K. Because of this it will eventually reach 0K

    The 2nd black body cools much less quickly because it radiates to a fixed 272K. Eventually the 2nd black body will reach the fixed 272K of the shell.

    Only a few people on the second body will notice much difference, 1K change is not very much. Those on the first body will not be caring much, they will have been frozen to death long ago!

    I am sorry but I can see no point in these examples.

    However there are interesting observations to be made. The first body has no heat source, internal or external and because it is 'black' it will cool at the maximum possible rate to 0K.

    If it is not black it will cool at a lesser rate, dependent on the surface emissivity. This could be very low indeed if it had a highly polished surface or even multiple surfaces; that is the principle behind using multilayer foil insulation (MFI) on spacecraft.

    The point is the MFI stops heat getting out of the craft by reflecting it back into it, so the craft does not cool down quickly.

    The MFI also reflects incoming radiation away from the craft, which is convenient because it stops the Sun heating it up too quickly. For these reasons MFI is sometimes called 'a thermal blanket'.
  34. PMEL Carbon Program: a new resource
    guinganbresil -and in my opinion, is most likely, caused by one of the other major non-anthopogenic factors.

    Yes, but that's just an opinion. And word-smithing doesn't hide the critical flaw in your hypothesis.

    They did not consider the effect of changes in the other major factors, specifically upwelling

    Again - see comments @ 23 & 25. You linked to those DIC graphs without actually understanding what they revealed. That's your bad. If you don't want to accept what the science says on this topic, then fine. But please don't be selling us an alternative ocean acidification mechanism that doesn't even make sense.
  35. Prudent Risk
    Albatross... I've spent a lot of time in China (my wife is from China) and I can tell you the smog is shocking. My wife's aunt lives in a high rise just up from one of the rivers in Chongqing, maybe 1/4 mile from the water's edge. In the summer most days you can barely make out the buildings on the other side of the river.

    Interestingly, I remember almost the same thing when I was a little boy growing up in East Tennessee. Everyone used coal furnaces and in the winter everything was covered in suit and you could not see 1/2 a mile ahead.

    China is closing down old dirty coal fired power plants at a fairly rapid pace. I'm also concerned at what this is going to unleash in terms of extra warming. If mid-century cooling was aerosols, is the same thing going on now?
  36. Ice age predicted in the 70s
    At the intermediate level, this is the final sentence in the caption for Fig. 1 ... "In no year were there more cooling papers than warming papers."

    Yet it appears in that very chart that there were more cooling than warming papers in 1971 (2 vs. 1).

    Am I misinterpreting either the chart or the assertion in the caption?

    The basic premise remains solid that climate papers in the period leaned heavily towards suspected warming, but it's best to correct overreach, before the "doubt mongers" use your own words against you.
  37. Motl-ey Cruel
    I think it's a little worse than that with Lubos Motl. The guy quite literally possesses a genius level brain, he's just choosing to apply it very selectively. The tiff that I got into with him over the Phil Jones interview he was trying to tell me that something that "did not have a 95% confidence level did not exist." It was absent, so there was no warming since 1995. I was shocked that a person of his level could make such an utterly absurd statement about statistical significance.

    My suspicion is that Lubos Motl has a political ax to grind and he will attempt to use the skills he has to further that agenda regardless of reality.
  38. Motl-ey Cruel
    My post @ 21 should have read:

    "... goes to show just how what genuinely good people they are and how much confidence they have in the science. "

    Dana, good for you to engage the aggressive and misguided crowd at Curry's blog-- you probably realise this, but I'l say it anyways, you are very likely wasting your time their. Don't confuse them with the truth and reality, it angers them
  39. Prudent Risk
    I like that analogy of the car's brakes. As with most things, prevention is better than cure.

    I'm really concerned that the huge aerosol loading from Asia is providing quite a substantial buffer, that may be giving some a false sense of security.



    Image from here.
  40. Dikran Marsupial at 05:27 AM on 26 February 2011
    2nd law of thermodynamics contradicts greenhouse theory
    damorbel - The point I was making is that you can reject any scientific theory regarding the nature of reality by demanding provable facts - but that doesn't make it rational or scientific behaviour.

    Consider a thought experiment, a blackbody object exists in a hard vaccum; initially the object is 273 degrees Kelvin (for the sake of argument), but it will cool by radiation to its environment which is at zero degrees kelvin. Now consider a second identical black body, also initially at 273 degrees kelvin, but now enveloped by a concentric hollow sphere of a blackbody material, leaving a gap all around of 1mm containing a hard vaccum. The shell is maintained at 272 degrees Kelvin. Which object will cool faster and why?
  41. Motl-ey Cruel
    Sure, I'm pretty patient when it comes to discussing the scientific evidence. Though there are limits - I've been commenting on Curry's "hide the decline dishonesty" post for the past day, and I'm to the point where I'm no longer responding to several of the commenters there, because it would just involve a Gish Gallop whack-a-mole on my part. Plus they're very rude people.

    But since Motl banned me from his site after just 4 comments, I never reached the point where my patience with him ran out! Motl doesn't understand climate science, but he's capable of understanding it (based on his physics background), so if he were willing to learn, I'd be willing to discuss it with him. Unfortunately he seems completely disinterested in learning.
  42. 2nd law of thermodynamics contradicts greenhouse theory
    Re 371 Dikran Marsupial, you wrote:-
    "Matching experimental results does not prove that the quantum explanation of black body radiation is correct (however it is repeatable)."

    I'm afraid I do not understand what you expect of quantum theory other than 'matches experimental results'. The essence of a good theory is that it enables new experiments to be devised which produce results that could not have been predicted with previous theories. Do you feel that quantum theory is deficient in this respect?

    Also you wrote:-
    "Nobody claims that the upper atmosphere does raise surface temperatures. The energy that causes the temperature of the surface to rise is from the sun"

    All significant climate energy comes from the Sun. The question is about how it is distributed.

    When you write:-
    "the upper atmosphere being warmer than outer space just means the surface looses energy to outer space less quickly and hence its equilibrium temperature is higher"

    Now there are various explanations for this and the presence of gases that radiate towards the surface in the infrared (GHGs) is the matter in hand.

    It is well established that matter cools when there is a net transfer of energy away from it. Correspondingly its temperature rises when energy is transferred into it.

    When you say "looses energy to outer space less quickly and hence its equilibrium temperature is higher", you are of course talking about a change in energy distribution.

    Now according to the 2nd law of thermodynamics a temperature difference is needed for a change of energy distribution and the also other way round, a change in energy distribution is always accompanied by a temperature difference.

    You seem to agree that it the CO2 in the atmosphere causes a surface temperature rise and many say that it is radiation from increases in CO2 that causes this.

    However this explanation would need the CO2 in the atmosphere to be warmer than the surface otherwise it will be the CO2 that is warmed by the surface (2nd Law).

    Personally I can see no other effect of CO2 that comes anyway near explaining temperature changes of any sort. Is there any other effect, in your opinion?
  43. Prudent Risk
    Dang sorry, that was sloppy. Comments #1 and #3 are correct that the text should have read "unlikely to be more than 4.5°C". I've corrected the text accordingly, thanks.

    michael #1 - I provided a link to an article I previously wrote on the costs of carbon pricing. Click the link for more details.
  44. Prudent Risk
    Um ... After reading Annan & Hargreaves 2009, it seems that their result is the opposite of your presentation: they concluded that there was a 95% probability that sensitivity is less than 4.5 C (actually, within the range 1.3-4.2), using the Cauchy prior, updated by the ERBE data.
  45. Motl-ey Cruel
    Robert @20,

    All too true (well most likely). It is odd though that Dr. Motl has not been here to defend his misguided understanding of the science.

    Dana just picked one of the most egregious errors in Motl's post, but Motl erred in practically every one of his "rebuttals".

    I think John and Dana are still being willing to engage Dr. Motl and discuss the science, even after the personal attacks that he has made against them, goes to show just how what a genuinely people they are and how much confidence they have in the science. They are bigger and better people than I.
  46. Prudent Risk
    Excellent post. It's rare that we get a chance to see the risks quantified and set out in such a clear way. I think when people see what a gamble the business-as-usual policy represents, their reaction is to support prudent evasive action - in the same way that they shell out hundreds or thousands of dollars in house insurance every year. They prefer losing the money than gambling that there won't be a fire, a flood or a break-in.
  47. PMEL Carbon Program: a new resource
    Dikran Marsupial - If you interpret my statement that non-anthropogenic factors are 'glossed over' as an accusation of deception, it was not intended as such.

    The 'pattern' I sense is as follows:

    1 - Some parameter 'A' causes 'XYZ' which is not desireable.

    2 - Parameter 'A' consists of a collection of major non-anthopogenic sources (B + C + D +...) and a collection of minor anthropogenic sources (q + r + s +...)

    3 - Since we are mostly concerned with the most salient non-anthopogenic factor (due to funding, scope of research, ability to affect the factors, whatever...) we re-arrange the equation to:

    q = A - (B + C + D + ...) - (r + s + ...)

    4 - We now prepare plots and graphs where we remove the major non-anthopogenic facctors and less salient anthropogenic factors (look up in this thread for examples!)

    5 - Armed with our graphs and plots of non-anthropogenic factors we now conclude that we can mitigate 'XYZ' by reducing the non-anthropogenic factor 'q'

    6 - There is an unstated conclusion that 'q' causes 'XYZ' - this is applying a 'Fallacy of Composition' It is clear that 'q' could cause 'XYZ', but 'XYZ' could be, and in my opinion, is most likely, caused by one of the other major non-anthopogenic factors.

    In the specific case of Feely et al 2008 they concluded that:

    "...the ocean uptake of anthropogenic CO2 has increased the areal extent of the affected area."

    They did not consider the effect of changes in the other major factors, specifically upwelling. They came to this conclusion by taking essentially one temporal measurement and projecting the change in areal extent by subtracting the anthopogenic signal. They have no measurements of the affected area from pre-industial times. This is a great example of the 'pattern' I am sensing.

    No deception - just wrong.
  48. How We Know Recent Global Warming Is Not Natural
    Jesus - the possibility exists that there is a 'natural' factor we are not accounting for. For example, Roy Spencer's "internal radiative forcing" hypothesis. If climate sensitivity is sufficiently low, it opens up a window where an unknown 'natural' effect could account for a majority of the recent warming.

    But sensitivity would have to be well below 2°C, and there would have to be a very strong natural effect that we're not accounting for. It's exceptionally unlikely, but not impossible.
  49. Prudent Risk
    Dana,
    I always like your posts.

    In paragraph 4 I think you mean "unlikely to be more than" (not less than). I would be interested in expanding the reference to the minimal costs of reducing carbon emmissions.
    Moderator: this post can be deleted.
  50. Hockey Stick Own Goal


    Figure 1: Moberg et al. 2005 NH (blue), Mann et al. 2008 EIV NH (red), Ljungqvist 2010 NH (green), and GISS land+ocean NH (black). Courtesy of Robert Way and John Cook.

    This is a fascinating graphn thanks Dana. Firstly the reconstructions do follow measured temperatures since ~1900s until 1990 ish which is reassuring to a degree, after which things get hot quickly, 0.2C a decade from 1980, or ~0.6C on 30 years.

    Looking at the graph two things get my interest, there appears to be a ~1000year natural temperature variation of about 0.3C (0.3C either side of the mean) arround a mean of -0.1C (from 0yr to 1980ish) with an added variation of ~+/-0.2C arround the running mean, meaning that (0.3C + 0.2C) or 0.5C above -0.1C would be a thousand year extreme warm year, so that is +0.4C on this chart and there are 2 spikes in blue of that magnitude in the middle of Medeival NH warming event.

    However the mid 1000-2000 cold dip period is cooler than the previous one between 0-1000 years by about 0.1-0.2C suggesting a possible cooling between the two, which is also in keeping with the 2000year cooling trend found in the arctic temperature record and in keeping with orbital variations in the NH which leading a general cooling of the NH at the present time, although this is a very slow cooling.

    All things being equal therefore by natural variation the NH should have been warming from 1500-1600 on wards and 1900-2000 should be the peak of the warming. Without the cooling trend it would be expected from the natural variation that the NH would reach another 1000year peak hot round about now, however this peak should be +0.2C mean with a year to year possibility of +0.2C or +0.4C just like in the 900-1100's and although for an individual year may even surpass this, the probability is less 1:1000 or more.

    Lets not forget the long term cooling due to orbital changes in the NH (clearly the arctic would amplify this effect as orbital effects are greatest nearer the poles), which should be bringing the mean down to lower than -0.1C (i suspect it is -0.1C as the mean for the whole series is skewed to 0C by the inclusion of the recent hot years), which means to get any year hotter than 0.4C than 2000year mean would be a truly exceptional event via natural variation.

    Lastly it looks like the mean has suddenly jumped, (would expect to phase jumps in a choatic system) and the new mean seems be a lot higher as there have just been a 10year period were then mean is 0.8C higher (than -0.1C). It is also of note that 2010 from solar and Nino (mod El Nino 5 months, Strong La Nina 7 months) activity should have been a cooler year than average, yet it was the hottest yet and November 2010 was in a well established La Nina and histroical low of sun activity and yet was also the hottest yet.

    So if 2010 and its weather was a cold year, what is a warm year going to be like?

    Could the mean have shifted again in 2010 with the earth being tipped into a hotter regime like it probably was 1998?

    Would this be in keeping with a step changing choatic system and that would mean that the jumps should get more frequent if the warming influence is maintained?

    As for Climate sensitivity, in the pliocene it 3-5C hotter despite all the natural variation of millions of years, and thus the only substantially different variable was the pCO2 at 350-400ppm although 350ppm more robust from recent evidence. 3-5C would take ~1000years to effectuate due to lags in the system however 60% is realised in the first 100year or so, that means we can expect at least 1.8C to a maximum rise of 3C by 2100, if CO2 levels fall to 350ppm ish.

    The Earth is a choatic system and therefore will have multiply possible CS as parameters change, the amount of ice will make a difference, the orientation of the continents (pliocene was similiar to now), and therefore CS will vary and have high and low possibilities. From the above long term CS for doubling can be high (3-4x pliocene temperature range) and as at present the earth has a pole whose albedo turn arround is very high going from ice to sea which makes sense as a CS amplifyer especially if permafrost GHG gas release is also considered.

    Also all the changes being observed in the system are occuring faster than expected by a CS or only 3C.

    Anyway it is very likely CO2 will hit 450-500ish the way things are going and that is well too high for serious consideration of there being any widespread fruitful scenarios for the future.

    An interesting graph clearly shows the globe is warming and very quickly, however at least natural variation should trend temperatures down a little, unless of course the natural variation seen in the graph is actually mainly a sea-saw NH / SH event due to long term flow patterns in the AMOC as that makes the current global warming even more impressive and is it likely that flucation could be changed or interupted if an external heating influence is added in.

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