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Comments 46601 to 46650:

  1. Making Sense of Sensitivity … and Keeping It in Perspective

    nealjking @76.

    I have a feeling another look at what was said @65 and particularly its reference to comment@57 could be useful to this interchange we are having.

  2. Making Sense of Sensitivity … and Keeping It in Perspective

    MA Rodgers:

    The Stefan-Boltzmann formula is the integral of the Planck spectral energy distribution over frequency (with no weighting). But the issues that give rise to the greenhouse effect (different absorption coefficients in different frequency bands) are frequency-specific. So the treatment in terms of S-B does not have nearly the specificity to explain the GHE.

    Here's another way to see the point: The constants in the S-B equation, and therefore in your ΔF/ΔT equation, do NOT depend in any way on the composition of the atmosphere. So if the equation were valid, it would be valid for any value of the concentrations; including 0 for the GHGs. But then there would be forcing with no GHGs, which is a contradiction.

    What determines the loss of radiated flux are the temperature differences at specific frequency absorption bands (due to the change in altitude of the critical point where optical depth = 1); using the Planck distribution, this gives the change in spectral density, which is integrated over the region of the spectrum that is absorbed by the GHGs. But the temperature difference for a particular band will depend on the GHG's absorption frequencies and concentration, and will differ from band to band. The total change in flux determines the radiative forcing.

  3. Making Sense of Sensitivity … and Keeping It in Perspective

    nealjking@69:  I would still like Sks readers to be open to the possibility that the Economist article is a subtle kind of 'hit piece' designed to leverage the magazines well-known reputation for balance on behalf of climate deniers.  As I detailed, the author makes the point he wants to leave readers with in his first sentence.  His LAST sentence is just there for 'plausible deniability': so he can claim 'balance' when confronted.  Maybe I'm innacurate in this, but I've seen it done before. The overall tone of the piece is to project doubt about climate science.  But as I've said elsewhere the REAL remaining doubt about global warming is in the costs of mitigation, damage, and adaptation.  This is not trivial: if the cost of mitigation is as low as I've seen it estimated, then it frankly DOESN'T MATTER whether the climate sensitivity is 2C or 4C: we should mitigate.  Can 'The Economist' tackle that ECONOMIC issue?  As it is, it seems to have a serious case of pointing out the grain in someone elses eye while missing the log in its own eye.

  4. helenavargas at 03:09 AM on 1 April 2013
    The Scientific Method

    When I introduced undergrads to the scientific method, I used to emphasize the iterative nature of the process:  tests of hypotheses may lead to theories, but the testing continues.  That in turn may require reformulated hypotheses, but even those aren't worth much if they can't be tested and survive testing.  I wanted to emphasize that science isn't an ideology (accepted for faith once and for all time) but a process of approaching the best representations of facts in nature.  Pseudo-skeptics accuse scientists of the same kind of faith that religionists praise, and I tried to do my bit to defuse that idea.

  5. Making Sense of Sensitivity … and Keeping It in Perspective

    nealjking @70
    You say "...the Stefan-Boltzmann formula for total blackbody radiation power is not applicable in the context of the enhanced greenhouse effect."

    Yet:-

    (1) Temperature increases in a zero-feedback-world are said to be easier to quantify.

    (2) That zero-feedback quantification appears to me to utilise the S-B formula, but for some reason that use is not very apparent. (I'm sure it used to be more apparent but now a search of the web turns up pages of denialists saying S-B is no good with zero reference to who it is they are having a go at for thinking otherwise.)

    (1) Non-feedback sensitivity is easier. According to AR4 - "While the direct temperature change that results from greenhouse gas forcing can be calculated in a relatively straightforward manner, uncertain atmospheric feedbacks (Section 8.6) lead to uncertainties in estimates of future climate change."

    And TAR - "In other words, the radiative forcing corresponding to a doubling of the CO2 concentration would be 4 Wm-2. To counteract this imbalance, the temperature of the surface-troposphere system would have to increase by 1.2°C (with an accuracy of ±10%), in the absence of other changes."

    A value of ECS-with-feedback ±10% is something we can today only dream of and this being so, I would suggest that, whatever the method which yields this non-feedback sensitivity, it should be more widely known, if for no other reason than to bash denialists with.

     

    (2) Does that method use the S-B formula? The S-B formula does give a ~1°C which is encouraging. And dodging all the denialists, I did find Roe & Baker 2007 who have a Suppliment where they use S-B to enumerate λo for use in a model which includes feedbacks.

    And the RF emissions from Earth are of the form of blackbody radiation, although highly motheaten. If a GHG increases to take another bite, I see no fundamental problem why the RF reaction wouldn't be as a blackbody all the way down to surface temperature.

    Of course this is nowhere definitive but I feel there is enough weight to counter your assertion of 'S-B non-applicability'  by saying  - The planet may not be a blackbody but it apparently behaves enough like one for ΔTs with zero-feedback to be derived from S-B and so it is likely that is how it is derived.

  6. David Kirtley at 01:44 AM on 1 April 2013
    Back from the Dead: Lost Open Mind Posts

    Also, the link at Oct 19, 2007: IPC projection falsified is actually for Oct 19, 2008.

    Moderator Response: [DB] Fixed; thanks!
  7. The Scientific Method

    The link to the textbook fails and there's a font problem with "The four steps above form the basis of a scientific inquiry; they constitute a simple model for the scientific method. One possible sequence is 1, 2, 3, and 4. If 2 is true, what are the consequences? Testing (4) should include considering the opposite of each consequence in order to disprove 2. If 2 can be disproved, then start again with step 1."

    Moderator Response: [DB] Fixed; thanks!
  8. 2013 SkS Weekly News Roundup #13

    chriskoz:

    Also check out the Climate Institute's report, Global Climate Leadership Review 2013, for addtional details about the LCCI.

    Note: The article, Asia cuts its carbon faster than Europe summarizes the findings of this report.    

  9. 2013 SkS Weekly News Roundup #13

    chirskoz:

    The article, Asia cuts its carbon faster than Europe, contains the following paragraph:

    The report, the Climate Institute/GE Low-Carbon Competitiveness Index, published by the Climate Institute, was first released in 2009. This year’s edition relies on data from 2010.

    I have quickly perused the website of the Carbon Institute for a definition of the Low-Carbon Competitiveness Index (LCCI). The definition I found is embedded in the news release, Australia alone in low-carbon competitiveness slide posted on Mach 19, 2012.

    The (LCCI) index measures carbon competitiveness through the examination of nearly 20 indicators in three areas: sectoral composition (historical snapshot of current economy – e.g. transport, trade emissions intensity); early preparedness (e.g. investment in clean energy, growth in emissions); and future prosperity (e.g. investment in education and infrastructure).

    The compilation of the LCCI is a joint effort between the Carbon Institute and GE Australia and New Zealand.  

  10. Earth Encounters Giant Speed Bump on the Road to Higher Sea Level

    Using a generous and simple 30-year linear for thickness (PIOMAS/CTSIA), I have winter max eventually moving to mid-February with ice finally disappearing on February 11th, 2076.  The 10-year linear has it in 2047 on March the 12th.  No, I'm not putting money on either.  I just can't see an ice-free Arctic year-round, unless we hit 600ppm and stay there for a while.  Yet I speak from within the momentum of my own culture.  It's hard to imagine what general circulation changes will occur when ice is just beginning to form in December, and harder to imagine what those changes will mean for the further (lack of) development of the ice. 

  11. 2013 SkS Weekly News Roundup #13

    The first article just mentions that China overtook Germany & UK in "Low-Carbon Competitiveness Index" and is placed third while Germany and UK fell to places 6 & 5. And that US rates bad: no score, apparently out of competition.

    I cannot find what that LCCI means, so I have no perspective on this rather surprising news, because the popular believe is to blame China on increased emissions, that grow still faster than the renewables, period. I would like to see some analysis of that LCCI, particularly the most interesting numbers: what dent it makes in each contry's emissions now and/or how does it influence the prognosis of future emissions.

  12. Earth Encounters Giant Speed Bump on the Road to Higher Sea Level

    CraigD@21

    Iteresting question, I haven't heard any prognosis about zero WIM. Looking at PIOMAS death spiral, with full rotation of 36y, it will have taken ~40y for the summer ice to reach zero (I agree with you and Maslowski on that). By that time, it looks like WIM will be at the point where summer min has started. So my wild guess is: it'll take another ~40y if the process continues at the same speed.

    So my  wild, uneducated guess for zero WIM is: 50y. Interesting indeed, as it may be within the lifetime of some of us. Anyone wants to make another/better guess?

    How does it influence the IS melting? Does it make sense in context of SLR rate? Yes IS melt should increase (some 10 times on average from their current contribution of 1mm/y), to fullfil the predistion of ~1m SLR by 2100 the semi-empirical models. Such increase makes sense to me.

  13. Making Sense of Sensitivity … and Keeping It in Perspective

    shoyemore:

    The most explicit derivation of the EGHE that I have seen personally is at the end of John Houghton's The Physics of Atmospheres; however, the derivation is effectively scattered through the book, partially in exercises.

    The explanation I gave above is from Pierrehumbert's book, but since I have only an early draft of the book, I don't know if he derives the entire formula explicitly; but he probably does.

    It's unfortunate that Weart's website, The Discovery of Global Warming, side-steps the derivation: I think he decided it was too hard to present.

  14. Making Sense of Sensitivity … and Keeping It in Perspective

    MA Rodger,

    The equation cited (in some form or other) goes all the way back to Svante Arrhenius (1896), who wrote (see his bio on Wikipedia): If the quantity of carbonic acid ... increases in geometric progression, the augmentation of the temperature will increase nearly in arithmetic progression.

    I underlined "nearly" so I presume Arrhenius derived the relationship from his observations, and knew it was only approximately true.

    The place I encountered the equation was on page 36 of David Archer's Global Warming: Understanding the Forecast , where he stated it applied to long-term equilibrium changes only. Nielson-Gammon used it in a short-term context with a "transient" value for K.

    Most websites dealing with this topic, like Science of Doom, go straight to the radiation physics.

    Is there a way to derive this approximate relationship from the radiative transfer laws?

  15. Making Sense of Sensitivity … and Keeping It in Perspective

    I posted a comment about two hours ago and although it was visible initially it has now been disappeared.  Is this due to snippage or should I post again?

    Moderator Response: [DB] The moderator on duty at that time deemed it too far off-topic.
  16. Making Sense of Sensitivity … and Keeping It in Perspective

    MA Rodger:

    I mean the Stefan-Boltzmann formula for total blackbody radiation power is not applicable in the context of the enhanced greenhouse effect.

  17. Making Sense of Sensitivity … and Keeping It in Perspective

    ubrew12:

    #61: You start off complaining that the author left his point to the end: "But there's a reason for that placement: how many readers make it to the END of such an article?"

    #68: Later, you point out that he made his point in his first sentence: "The author made his point in his first sentence."

    Which is it?

    All I'm pointing out, as I subscriber who reads The Economist every week, is that their articles are frequently written in such a fashion that you need to read to the very end to get the picture.

    Does that make it a bit harder to digest their articles? Yes, it does. But they've been in publcation since 1843, so I guess they think they know what they're doing.

  18. Making Sense of Sensitivity … and Keeping It in Perspective

    nealjking@66 - I think Economist readers are like any other.  The author made his point in his first sentence.

  19. 2013 SkS News Bulletin #5: Alberta Tar Sands and Keystone XL Pipeline

    Thanks, Chris & John. The reason I didn't publish it here is that it was a little bit too political and opinionated for Skeptical Science norms.

    Michael Tobis and Dan Moutal have a great blog going at Planet 3.0, with a slightly different focus than SkS, with more discussion on sutainable technologies and cultures, but with the same overall goal: promoting understanding and solutions on climate change. I urge all SkS regulars to check it out.

  20. Earth Encounters Giant Speed Bump on the Road to Higher Sea Level

    Interesting. I had no idea that La Nina and El Nino had such impact on sea levels. However, I expect that after the Arctic goes ice free in summers after about 2017-2020, the Greenland Ice Sheet melting will accelerate significantly. With the Arctic ice gone the summer sun will warm the Arctic Ocean. The warming of the Arctic Ocean will also accelerate at more ice is lost, and the time of no ice lengthens. With this, the Arctic will warm considerably over its current state. As the Arctic warms, the Arctic Winter Ice Maximum will decrease. Now the big question is how long will it be before the Winter Ice Maximum reaches zero? As the WIM decreases each year, Greenland will melt more and more ice. It is going to get interesting. 

  21. Making Sense of Sensitivity … and Keeping It in Perspective

    MA Rodger:

    I don't believe the equation

    ΔF/ΔT = 4σT^3

    has much relevance in this context. The blackbody spectral radiation formula is not applicable in the context of the greenhouse effect.

  22. Earth Encounters Giant Speed Bump on the Road to Higher Sea Level

    Philp Cohen - Duly noted. I think a tweak is all that's required.

    Nichol - depending on the time frame under consideration, there can actually be a net gain, or net loss, of moisture from the continents. There doesn't seem to be any long-term trend over multiple decades - See Ngo-Duc (2005) linked to in the blog post - but for any given decade the trend can vary. From 2002-2009 , for instance, there has been  a net gain in continental water mass equivalent to a fall in global sea level of around 0.2 mm per year (Jensen [2013]). Not that surprising given the ENSO trend.

  23. Making Sense of Sensitivity … and Keeping It in Perspective

    ubrew12:

    Articles in The Economist are frequently not designed along the well-known journalistic "upside-down pyramid" approach: It is often the case that you have to read to the end to get the point.

  24. Earth Encounters Giant Speed Bump on the Road to Higher Sea Level

    Count me as another who misread the title and considers a vivid, memorable metaphor a bad thing if it inclines you to remember a falsehood. The recent rise is a speed bump-up, not a speed bump. Metaphor aside, good piece.

  25. Earth Encounters Giant Speed Bump on the Road to Higher Sea Level

    Still open to a better metaphor.


    Snakes and Ladders.

  26. To frack or not to frack?

    gws:

    With all due repect, the title of your OP is all-encompassing with repsect to the upsides and downsides of fracking. Futhermore, there is no other article posted on SkS that addresses fracking and water impacts.

  27. Earth Encounters Giant Speed Bump on the Road to Higher Sea Level

    Looks like if there will be more rain, there is an argument for more effort in keeping that water on land, or replenish ground-water reserves. More dams, even more so where water can 'leak away' into underground aquifers. In stead of returning to the oceans.  I imagine that in the past such locations for dams have been avoided?

  28. To frack or not to frack?

    "Do any of you know what chemicals go into fracking?"

    thanks for asking: here's the ones the industry *admits* to.

     

    http://fracfocus.org/chemical-use/what-chemicals-are-used

    Methanol? Formic acid? Potassium hydroxide? Trust your well water to thousands of oil and gas wells going through your aquifer? Not me, not yet.

  29. David Kirtley at 08:40 AM on 31 March 2013
    Back from the Dead: Lost Open Mind Posts

    I was able to get to a "still missing" tamino post:  Oct 5, 2007 Wait for it...

    Moderator Response: [DB] Added, thanks!
  30. Making Sense of Sensitivity … and Keeping It in Perspective

    Shoyemore @63

    Your equation is of course mathematically identical to the equation @43.

    The question asked (or was it a demand) by elsa about an equation linking ΔCO2 with ΔT first appeared @38 - “Perhaps, since you say that the link between CO2 and temperature is derived from physics, you can tell us what the equation is that links the two and how it is derived?” - itself prompted by the statement @24 - “Both the models and how CO2 affects temperatures are entirely derived from physics.” So the question was a bit presumptious.

    The insistence on a single 'equation' kind of rules out addressing the model aspect but the CO2-temperature relationship when shorn of feedbacks can be reduced to that anticipated single equasion. Half of it I rather cheekily presented @57, the half which yields ΔF. From it with the derivative of the Stephan-Boltzman eqn (pretty much a constant for small changes in T) ΔT can be derived.

                                                          ΔF/ΔT = 4σT3

    This is all such straightforward stuff that usually just the result from it is quoted. A link to point folk at might be good but I cannot say that I know of one.

  31. Making Sense of Sensitivity … and Keeping It in Perspective

    ubrew12:

    Articles in The Economist are frequently not designed along the well-known journalistic "upside-down pyramid" approach: It is often the case that you have to read to the end to get the point.

  32. To frack or not to frack?

    @10: Who is your comment addressed to?

    The post does not address the fracking&water issue and was not intended to. Please take discussions of the water issue to other venues. I know the issues cannot be completely seperated, that this discussion should be not morphing into one not related to the post topic.

  33. Skeptical Science Firefox Add-on: Send and receive climate info while you browse

    I'm having trouble signing in with the Firefox add-on. I type my username and password, click "log in" but nothing happens... Same thing happens with version 12 and 19 of the Firefox. Any suggestions?

  34. Making Sense of Sensitivity … and Keeping It in Perspective

    Elsa, @55

    ∆T = K Ln(CO2final/CO2initial)"/Ln(2), where Ln(.) is the natural log function.

    If you can use Excel, it should be easy for you to download one of the temperature records, and the CO2 Mauna Loa series since 1958.

    Plot ∆T since 1959 against the right hand function and come up with a rough estimate for K, or at least the transient K for a non-equilibrium situation.

    John Niesen-Gammon has a good post here about this equation.

    http://blog.chron.com/climateabyss/2012/10/carbon-dioxide-and-temperature/

  35. Earth Encounters Giant Speed Bump on the Road to Higher Sea Level

    Speedbumps works well for me - a temporary slowing often followed by an aggressive acceleration. In reality there's often a futility to the few speedbumps that get built, they provide a false sense of security and stop people looking at the bundle of measures needed to actually cut traffic speed to a safe level.

  36. Making Sense of Sensitivity … and Keeping It in Perspective

    Sphaerica - Not only are most of Elsa's posts offtopic, but Elsa is persistantly repeating false statements from who knows where, without any supporting evidence. We are replying with papers and links that as far as I can see are being simply ignored. Ignorance is excusable - we are all ignorant of many parts of sciene - but wilful ignorance isn't/ This appears to be sloganeering and I would hope moderators would take a stronger line in demanding substantiation of claim (in the appropriate thread).

    Moderator Response: [DB] Indeed, much latitude has been given in the now-vain hope that elsa would have something substantive to offer to support her assertions. Until that new materiel is forthcoming, no further diversions to the OP of this thread will be permitted.
  37. Making Sense of Sensitivity … and Keeping It in Perspective

    'Location, location, location'  Many commenters on this thread have mentioned that the author of the Economist hit-piece somewhat redeems himself by mentioning in the article's last paragraph the potential of a 4 C rise, which is 'hardly reassuring'.  But there's a reason for that placement: how many readers make it to the END of such an article?  

     

    To recount: "OVER the past 15 years air temperatures at the Earth’s surface have been flat"  This is the very first sentence, the one most likely to be read and retained by readers.  No provisional, like "of course, in the past 20 years, the surface temperature anomaly has almost doubled".  This could literally be the second sentence of his article: why isn't it?

    The second section is titled 'The insensitive planet'.  If you were just skimming this piece, what message would you take away from that title?

    The third section is title 'New Model Army'.  This section makes it very clear that there is a 'war going on' between the [possibly communist] IPCC and a 'New Army' of rambunctious young Scientists who are all converging on a sensitivity of 1-2 C.  Who will win?  Unsure, but we know who is losing: "the chances of climate sensitivity above 4.5°C become vanishingly small"

    There's 'obviously' a war going on in the climate science community, so why take action before 'they' resolve it?  As the fourth section is titled, there are 'Clouds of Uncertainty' on this whole subject.  Could the lack of recent atmospheric heating be due to better ocean heating?  The author: "Perhaps it lies in the oceans. But here, too, facts get in the way"  and there is a graph of the surface ocean ALSO not heating.  Again, if you're skimming this material, THAT'S the graph you're going to see, with its ready-made conclusion: Nope, its not the oceans.  Now the author produces the caveat that maybe warming is going into the deep ocean.  Or maybe not, since according to the author, that is "obscure". 

    In the section titled 'Double A-minus', the author directs the reader to sources of natural atmospheric heating, like the recent paper by Tung and Zhou.  It should be obvious that the ONLY reason this flawed paper deserves to be singled out is its use of the word 'natural'.  That's a very important word to the 'doubt is our product' crowd.

    All of this fresh doubt piled on IPCC's 3 C sensitivity leads to this statement, which Rupert Murdoch's 'The Australian' newsmagazine chose to lead off with: "If climate scientists were credit-rating agencies, climate sensitivity would be on negative watch".  Because, as we all know from the housing bubble, credit-rating agencies are the gold standard when it comes to understanding value...

  38. 2013 SkS Weekly News Roundup #13

    Missing link:

    Two key climate change concepts are ‘misunderstood’ [climatecentral.org]

    Moderator Response: [JH] Link inserted. Thanks for bringing this to our attention.
  39. Making Sense of Sensitivity … and Keeping It in Perspective

    The video that dana1981 linked @45 gives us the name of the author of the article - John Parker, Globalisation Editor of The Economist (although in their list of journalists, he is listed as Energy & Environment Editor. This would be a recent appointment as James Astill was for a while from 2011 Energy & Environment Editor ). Parker doesn't seem too fluent with his message in the video & has colleague Oliver Morton riding shotgun for him.

    And in the video Parker kicks off again telling us temperatures have plateaued for at leat the last ten years and possibly the last fifteen. This is bonkers. Temperatures, say GISS 5-year average, have 'plateaued' between 2003 and 2010. Yet the creation of that plateau only begins in 2008. Until the 2008 temperature arrives to influence the 5-year average of 2006, the data is wholly consistent with a continuation of the accelerating temperature rise. The plateau or flat or pause or whatever is only 5 years old, going on 6. It is never "possibly fifteen"!!

    There is also a further video featuring John Parker from December 2012, this time putting the questions to fellow Economist journos Oliver Morton & Ryan Avant in the aftermath of Doha.

     

    http://www.economist.com/blogs/babbage/2013/03/global-warming-slows-down

  40. Making Sense of Sensitivity … and Keeping It in Perspective

    NIck @54 - see A Glimpse at Our Possible Future Climate, Best to Worst Case Scenarios, which is relevant to the point you're making.

  41. Making Sense of Sensitivity … and Keeping It in Perspective

    @52 MA Rodger

    I have to agree: For the huge majority of general readers, the middle of the roaders, the take-home message of both the article and the video @45 (entitled "Global Warming Slows Down", misleadingly, as shown by the ocean warming) will be that there is less need to worry and therefore less need to act.  This is exactly the opposite of the truth but it is the message of the article.  

    To discuss ECS so deeply in the context of The Economist provides effective distraction from the core problem of policy inaction, something one can be sure many of its readers do not wish to see.  The second video interviewee does say that ECS sensitivity discussion might be meaningful if policy had been delivering action but that is not the 'take home', especially when the first interviewee jumps in to say that policy-makers prefer to look at the next decade or decades – as if the future of 2100 is of little concern.  

    One trouble is that knowledgeable readers can look at the article as relatively balanced  compared to so many poor ones generally.  Indeed such readers may be gratified that the detail of the science is finally being discussed for a general readership.  This can please the knowledgeable and serve to blunt critique from them. 

    However, by focusing on scientific uncertainty in ECS values, and avoiding discussion of the complete lack of action by policy makers and developed nations, the article's impact on most readers will be to confirm their economic preference to delay action.  The policy makers and developed nations, along with major corporations and rich individuals, all comprising the target market of The Economist, will be well pleased with this approach  

    In the context of economics and the Economist, the ECS discussion is a denialist distraction that works to delay support for action.  By discussing scientific 'uncertainty' that translates in many readers mind to 'policy uncertainty', which is code for let's do nothing for now until things are more certainty.  This is how 'lukewarmist' denial works in the media to support continued inaction.

    Scientists and climate policy experts need to start talking to media about certainty in the sense that media and the public understand.  If the minimum ECS is 2ºC and the current path is to at least 3CO2 by 2100 then the experts need to say, "On our current path it is certain that we will reach 6ºC and that will be utterly catastrophic for human civilisation" or "If all emissions stopped then warming would stop".   Science experts need to state that the uncertainty they are referring to has nothing to do with policy failures or the urgent need for large-scale mitigation action.

    Scientists have to start learning how to communicate definitely in public rather than being led into discussing uncertainty – even though that is in fact their area of expertise! 

    Paul  - www.climie.blogspot.ie

  42. Making Sense of Sensitivity … and Keeping It in Perspective

    elsa @55

    I do not see why you would consider it unhelpful to use a base 2 log. Would you rather increase complication by using a different base? If so, try:-

    ΔF = 5.35 In(C/Co) W/sq m

    There is no argument about this, even from denialists like Lindzen, Spencer & Christy mentioned above (although to include the Mad March Monckton may be a step too far). Your inability to accept that CO2 can be a cause of significant climatic change would be easier to address if you explained your position on this, rather than us trying to give you a crash course in basic science. The present process here is being so poorly directed because it is being directed by you.

    So what is your problem with CO2 being the most significant LLGHG?

  43. Making Sense of Sensitivity … and Keeping It in Perspective

    elsa,

    K = climate sensitivity, the degree to which the climate responds to a CO2 forcing or any other forcing.  The measure of the forcing of CO2 is 3.7 W/m2, and the value of K in this equation is between 2.0 and 4, with the most likely value being 3 or 3.5.

    A lot of people are currently engaged in estimating climate sensitivity using a very wide variety of methods.

    See here and here.

    Current estimates of climate sensitivity are in the range of 2˚C to 4.5˚C, although based on the way the earth is currently responding to a mere 0.8˚C of warming to date, it seems that even if we luck into a climate sensitivity of 1.6˚C (which is highly unlikely) we will still regret it dearly.

    Note: All of your posts are off topic. If you wish to discuss the basics of climate sensitivity (as opposed to the specific issues of climate sensitivity raised by the Economist article), post your comment on one of the two threads linked above. If you wish to ask questions about the physics of CO2, post your question here. Many people will be more than happy to answer your questions and help you to learn more about the science, to correct your misconceptions, however it is important not to clutter the wrong threads with random diversions.
  44. Earth Encounters Giant Speed Bump on the Road to Higher Sea Level

    'Slumps 'n' Jumps'?

  45. Making Sense of Sensitivity … and Keeping It in Perspective

    Sphaerica

    You say "The relationship between CO2 and temperature is:

    ∆T = K log2(CO2final/CO2initial)"

    Let us examine this.  We are looking at what would happen if the concentration of CO2 doubled so I guess CO2 final/CO2 initial = 2

    The log to base 2 of 2 = 1

    So what you say is that the change in temperature is K


    This in unhelpful to say the least.  What we need (-snip-) is a value for delta T that we can compare with actual temperatures and concentrations of CO2.  So please, what is that equation?

    Moderator Response: [DB] Off-topic snipped.
  46. Earth Encounters Giant Speed Bump on the Road to Higher Sea Level

    Ups and downs? Meh... 

    Still open to a better metaphor.

  47. Making Sense of Sensitivity … and Keeping It in Perspective

    Rethinking my post (#39) and gpwayne's (#47), I think we now have a pretty unassailable case against the lukewarmers - the only part of the scepticosphere that still has a leg to stand on.

    If +2°C is regarded as dodgy and +4°C is definitely dangerous, then even if Lindzen, Spencer and Christy's  (even Monckton's!!!) admitted ~1°C figure is correct, the second doubling to 1120 ppm puts us in trouble. As I pointed out before, if the world thinks that sensitivity is as low as the minority suggest, it makes it far more likely that little or nothing will be done to mitigate, or even stop the growth of, emissions.

    The only shred of Lindzen's ideas left to deal with is his contention that although the basic CO2 feedback is ~1°C, he claims there is a negative feedback from clouds based on his work with tropical clouds. Show that, even if that holds for the narrow band in the tropics, the probability is that it does not hold for the majority of the planet, particularly the polar regions, and the remaining scepticosphere case collapses entirely.

    That may not be enough to fully convince the voting public who have been relentlessly propagandised by experts. The standard infuriatingly deceptive but dumb denialist memes, that the general public are pretty receptive too, should be handled by large full page press ads in high circuation newspapers with the memes (it's the sun, it's not warming etc) down one side and SKS type rebuttals down the other.

  48. Making Sense of Sensitivity … and Keeping It in Perspective

    I think it would be easier for elsa to come out from under the bridge and explain why she/he believes that an increase in the insulative properties of the atmosphere will not increase global temperatures. The analogy of wearing a coat on a cold day should be something he/she has experience of, so why would anybody think the atmosphere wouldn't be governed by similar physics?

  49. It's not bad

    KenD.

    Bet on volume rather than area, and you will almost certainly have money in the bank.

    And sadly, Sphaerica is correct about time spans and realisations.  The only slight point at which I would diverge is that I suspect that the genie's already been out of the bottle for a few years.

  50. Making Sense of Sensitivity … and Keeping It in Perspective

    I'm a little surprised that my interpretation of this Economist article was considered too harsh by others up thread. For the record, rather than to convince folk, here is my counter-comment.

    I think all agree the article is mainly factual although it does kick-off in error (the 15-year flat temperature myth) which is never a good sign. In my view its analysis is straightforwardly denialist all the way down to near the end with but the occasional grudglingly-provided caviat (eg 'if deep oceans are heating, it may help explain things') suggesting otherwise.

    The end could perhaps have redeemed it, the end being its conclusion, its take-away message, except it doesn't recap its coverage and pronounce judgement. Rather it goes unsignalled into 'warning mode' in the final two paragraphs, the last being.

    Since CO₂ accumulates in the atmosphere, this (ie, 1,500GtC total emissions) could increase temperatures compared with pre-industrial levels by around 2°C even with a lower sensitivity and perhaps nearer to 4°C at the top end of the estimates. Despite all the work on sensitivity, no one really knows how the climate would react if temperatures rose by as much as 4°C. Hardly reassuring.

    The numbers used in the first sentence are low (ECS=1.6°C and “at the top end of the estimates” 3.2°C) although for the lower one that was the point. The second sentence comes from nowhere. What is the relevance to work on sensitivity to predicting climate after 4°C of warming? And if “no one really knows,” how come they ran an article on it two years back?

    Then the final comment - is it meant to be ambiguous? Depending on its missing noun, it can easily be read to mean anything from 'all climatology is inept' to 'mankind is in deep do-do'.

    In the paper version of The Economist, this article is a tight fit onto the page. It is possible it may have suffered some severe editing to get it to fit. Still no excuse though.

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