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Unforced variations: Aug 2014

Filed under: — group @ 5 August 2014

This month’s open thread. Keeping track of the Arctic sea ice minimum is interesting but there should be plenty of other climate science topics to discuss (if people can get past the hype about the Ebola outbreak or imaginary claims about anomalous thrusting). As with last month, pleas no discussion of mitigation strategies – it unfortunately does not bring out the best in the commentariat.


222 Responses to “Unforced variations: Aug 2014”

  1. 151
    Edward Greisch says:

    George Marshall’s new book “Don’t Even Think About It: Why Our Brains Are Wired to Ignore Climate Change” published by Bloomsbury US.
    http://climatedenial.org/2014/08/20/climate-change-the-slippery-problem/

    “DANIEL KAHNEMAN is not hopeful. “I am very sorry,” he told me, “but I am deeply pessimistic. I really see no path to success on climate “

  2. 152
    Russell says:

    Keen students of the influence of Orwell on the Climate Wars may wish to atttend Anthony Watts latest master class.

  3. 153
    MARodger says:

    A new paper promoting the Atlantic as the major recipient of recent global warming – Chen & Tung (2014) ‘Varying planetary heat sink led to global-warming slowdown and acceleration’ (abstract) – is getting prominent coverage within BBC World Service headlines this morning (On-line BBC coverage here). The worry with this level of coverage is Ka-Kit Tung has history of playing a rather strong game of “Where’s Amo” and doing so to promote his thesis that recent warming was 40% natural due to the AMO. (To compensate he sees a reduction in anthropogenic forcing assessments is required rather than a reduction in climate sensitivity.) The BBC on-line coverage suggests he is not far away from repeating this with this new paper.

  4. 154
    Hank Roberts says:

    New journal from China, first issue:

    http://engineering.cae.cn/engi/EN/abstract/abstract10625.shtml
    DOI not provided

    Ka-Kit Tung,Rong Zhang,Kevin E Trenberth.
    Mechanisms for the hiatus in global warming[J]. Engineering, 2014, 1(1): 46-48.

    Ka-Kit Tung1(),Rong Zhang2,Kevin E Trenberth3
    1. Department of Applied Mathematics, University of Washington, Seattle, WA 98195, USA
    2. Geophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration, Princeton, NJ 08540, USA
    3. National Center for Atmospheric Research, Boulder, CO 80307, USA

    Abstract

    The observed global mean temperature is the highest on record for the past decade but has plateaued to form an apparent “hiatus” in global temperature rise, with an almost zero short-term trend. Several speakers presented results on the hiatus and suggested possible mechanisms.

    Also in the same issue:
    Engineering 2014, Vol. 1 Issue (1) : 33-40 DOI: not provided
    Sybren S Drijfhout,Kevin E Trenberth,William G Large. (In)consistency of air/sea heat flux estimates, ocean heat uptake anomalies and top of atmosphere radiation budgets[J]. Engineering, 2014, 1(1): 33-40.

    Sybren S Drijfhout1(),Kevin E Trenberth2,William G Large2
    1. National Oceanography Centre, Southampton, Hampshire SO17 1BJ, UK
    2. National Center for Atmospheric Research, Boulder, Colorado 80307, USA

    This paper introduces the consistency between top of atmosphere (TOA) imbalances and ocean heat uptake, and the inconsistency between ocean heat uptake estimates and flux climatologies, and then gives some recommendations and outlook.

  5. 155

    #150–Almost certainly not. But I’ll leave the detailed debunking to those more adept in this topic than I.

  6. 156
    MARodger says:

    Walter Crain @150.
    The US temperature analysis you link to is the work of a Ron Clutz who I see last month provided two sets of similar nonsense for the good Cap’n Watts on the planet Wattsupia. So far there is no sign of this third set of nonsense being posted there and it would be telling indeed if it were shunned even by Cap’n Watts, given the dire standard of work that Watts happily exhibits on his planet.
    Then again, this particular nonsense may be too painful a subject for the good Cap’n. You may recall the pathetic and failed attempt by Cap’n Watts and his scurvy crew to get his magnus opus Watts et al (2012 unpublished) published. Clutz travels the same path and the links Clutz provides to the data he uses leads straight to Watts’ surfacestations website plus the 0.16°C/century result he obtained using Watts’ Class 1 sites is pretty much the same as the 0.155°C/century Watts got for his Class 1 & 2 sites.
    So given all that, you may find this SkS page debunking Watts et al (2012 deceased) also informative of this serving of nonsense from Clutz.

  7. 157
    Michael Hauber says:

    Walter at 150. A basic trick of the debate is to note that the US high quality surface stations are warming slowly (it used to be cooling), contrast this with the global warming rate which contains both the high quality and lower quality stations which have been ‘adjusted’ and imply that the global warming rate is due to the adjustments. However an analysis of unadjusted data for global stations shows about the same warming rate as after the data quality adjustments are made. The official warming rate after adjustments are made for the US is also much lower than that of the rest of the world, and presumably in line with the rate of 0.16/century that they claim although I haven’t looked into the details of this for over 5 years.

  8. 158
    Shaun says:

    Earlier this week, prominent climate scientist Michael Raupach used the occasion of a speech to the Australian Academy of Science to make an impassioned call to fellow scientists, urging them not to sit on the sidelines of climate politics.

    Professor Raupach, who runs the Australian National University’s Climate Change Institute, is a respected, experienced and inspirational scientist. I certainly appreciate his frustrations and concerns. I applaud his call for his colleagues get involved.

    But before doing so, they need to learn some crucial lessons about effective communication that go beyond just the frustrating reality that facts rarely win the day. If they don’t, their efforts will change precisely nothing.
    https://theconversation.com/speak-out-climate-experts-but-stop-making-tactical-mistakes-30732

  9. 159
    Shaun says:

    So what’s a climate scientist to do?

    Here are some tips. Have crystal-clear communication goals. Know what you want to do, how you will do it, and how to evaluate your efforts. If you don’t know what you’re trying to do, how can you know if you’ve done it?

    Own your political views. In the climate space, there’s no such thing as “not political”. Being a scientist does not inoculate you against the influence of your values, especially on contentious political topics. Why pretend otherwise?

    Be available. Your climate knowledge is invaluable, and many people need your input and your help. Make it as easy as you can for them to make the best possible use of what you know.

    Team up with different experts. Climate arguments and policy debates are by no means just about climate science. To be as effective as possible, you need to draw on the experience of experts in policy and politics, communication and media, and social sciences. You can’t do it all yourself, but the good news is that you don’t have to.

    Finally, keep being a scientist. And do this in two ways. First, keep doing the climate science (please). Second, approach your involvement in the political and communication space as you would approach your science. Look for evidence and ask questions, rather than making assertions about what works and what’s needed.

    Only an informed approach to the entire communication enterprise will stop us generating the same media white noise as those we need to disarm.
    https://theconversation.com/speak-out-climate-experts-but-stop-making-tactical-mistakes-30732

  10. 160
    Hank Roberts says:

    Planning ahead:

    http://www.clu-in.org/products/newsltrs/tnandt/view_new.cfm?issue=0514.cfm

    EPA 542-N-14-001 | Issue No. 65 May 2014
    This Issue Contains: Featured Articles

    Site Operations and Remedy Design: Hurricane Irene Flooding and Adaptation at the American Cyanamid Site
    Remedy Performance: Remedy Resilience to Flooding at the Rocky Mountain Arsenal
    Remedy Design: Long-Term Protective Measures Against Storms and Flooding at Allen Harbor Landfill

    This issue of Technology News & Trends highlights how remedies for contaminated sites may be vulnerable to the impacts of climate change and how measures may be taken to adapt remedies to the impacts. Potential impacts include extreme or sustained changes in temperatures, increased flood events or droughts, increased wind intensity, more frequent and intense wildfires, and sea level rise. The U.S. Environmental Agency (EPA) Superfund program has developed an approach that raises awareness of the vulnerabilities and applies climate change science as a standard business practice in site cleanup projects. …

  11. 161
    Chuck Hughes says:

    This sounds good but I assume there’s a catch somewhere.

    http://talkingpointsmemo.com/anga-sponsored/natural-gas-drop-carbon-emissions

    “On a per capita basis, U.S. carbon emissions are now at the level they were in 1961″

    Somehow I just don’t believe that but… I also noticed that the article says “Sponsored Message”.

    I think CO2 emissions are still on the rise last time I checked. Maybe someone can enlighten me on this. Thanks.

  12. 162
    Chris Dudley says:

    With lots of conflict over the Keystone XL pipe line including the present administration engaging in misunderestemating http://thehill.com/policy/energy-environment/214805-study-keystone-emissions-four-times-feds-estimate which we had hoped we were done with, there seems to have been a fairly smooth approval process for a powerline that will bring wind and hyrdo power to NYC from Canada. http://westfaironline.com/65039/canada-to-nyc-power-line-receives-environmental-approval/

    Why is a transmission line approval handled by the Department of Energy while a pipeline denial is left up to the Secretary of State who may well muff it? Most likely it is because every President since Reagan has failed to appoint an administrator for the Economic Regulatory Administration within the DOE as required by law. It is that administration which should handle cross boarder pipelines. http://www.law.cornell.edu/uscode/text/42/7136

  13. 163
    Hank Roberts says:

    For Walter Crain: you’re probably thinking of a picture like this one.
    Read about it in context.
    Don’t be fooled again.

  14. 164
    Tony Weddle says:

    Chuck.

    It could be true but misleading. Emissions actually rose last year and are projected to rise this year. Per capita emissions take into account population size. I’m guessing that population was a lot lower in 1961, so it could be that emissions on a per capita basis are no higher now than in 1961, but that’s kind of irrelevant if emissions, overall continue increasing. They are down, overall, over the last decade or so, but that is based purely on emissions occurring within the borders of the US, and doesn’t take into account total global emissions due to US economic activity or to emissions from exported coal (and, possibly, other fuels).

  15. 165
    MARodger says:

    Chuck Hughes @161.
    The stat is pretty-much true. Probably “since 1962″ would be a more advisable stat to use as 2013 & 2014 emissions are not collected yet and indications from the power sector suggest emissions will have risen, but only a bit.
    Of course you really must put this stat in context. Globally per capita emissions have rise 14% over the same period which means comparative to globally, the US per capita figure has dropped from 342% of the global average to 300% of the global average.
    My take on the relative national contributions to CO2 emissions is here (usually 2 clicks to ‘download your attachment’) (Per capita the actual worst offender isn’t shown. That is Luxembourg who have had a rather large steel industry for rather a long time.)

  16. 166

    On US emissions per capita: yes, the World Bank says the same thing, more or less:

    http://www.google.com/publicdata/explore?ds=d5bncppjof8f9_&met_y=en_atm_co2e_pc&idim=country:USA:RUS:CAN&hl=en&dl=en

    Tony is right. Here’s an EPA graph showing the absolute numbers for several GHGs (to 2012, so it doesn’t show the 2013 uptick):

    http://www.epa.gov/climatechange/science/indicators/ghg/us-ghg-emissions.html

  17. 167
    wili says:

    More fuel for the fire. From Berkeley’s Center for Science, Technology, Medicine and Society.
    https://www.youtube.com/watch?v=JJ9-jYfpwfw

  18. 168
    AIC says:

    Re #153
    Will RealClimate have a specific post on this?

    Science 22 August 2014:
    Vol. 345 no. 6199 pp. 897-903
    DOI: 10.1126/science.1254937

    Varying planetary heat sink led to global-warming slowdown and acceleration
    Xianyao Chen
    Ka-Kit Tung
    Deep-sea warming slows down global warming
    Re #153
    Will RealClimate have a specific post on this?

    Science 22 August 2014:
    Vol. 345 no. 6199 pp. 897-903
    DOI: 10.1126/science.1254937

    Varying planetary heat sink led to global-warming slowdown and acceleration
    Xianyao Chen
    Ka-Kit Tung
    Deep-sea warming slows down global warming

  19. 169
    sidd says:

    Amartya Sen tour de force:

    http://www.newrepublic.com/article/118969/environmentalists-obsess-about-global-warming-ignore-poor-countries

    ” To say that worrying about other species is none of our business is not ethical reasoning, but a refusal to engage in ethical reasoning.”

    sidd

  20. 170
    bjchip says:

    Does anyone know what has happened with Tamino? He has been silent for a longish time now.

  21. 171
    MARodger says:

    AIC @168.
    After hearing the Chen & Tung paper being mentioned on the news on Friday, I did a quick trawl on-line and found 2 graphics potentially from the paper here, and here. In lieu of a sight of the full paper, they may help the curious. In my view, they show timings of OHC rises that are somewhat different from that suggested by the available descriptions of the Chen&Tung thesis.

  22. 172
    Chris Dudley says:

    Sidd (#169),

    It turns out that the research on storage that Amartya Sen is calling for has already been done and the result is that not much is needed. http://www.engineering.com/ElectronicsDesign/ElectronicsDesignArticles/ArticleID/8272/Is-Storage-Necessary-for-Renewable-Energy.aspx

    I find this passage to exhibit a lack of rigorous thinking:

    “Robert Solow has extended this approach in a powerful way, integrating the sequential roles of different generations in terms of a comprehensive and easily understandable formula woven around the idea of living standards, whereby we want to make sure that future generations can enjoy living standards no lower than ours, and also allow them to ensure that their own successor generations have similar opportunities to live and provide for the future. There is a lot of wisdom in this understanding, but we must enrich it further by moving from the valuation of needs-fulfillment and human living standards to the valuing of human freedom—taking a broader view of our humanity, and not seeing ourselves just as “patients.””

    Solow’s formulation shows obvious concerns for avoiding impinging on the liberty of future generations to make ethical choices for themselves. I think there are other areas of confusion as well where the economist can not see wilderness preservation as part of species preservation or where a call for US leadership falls short of the coercive remedies we might apply such as carbon tariffs.

  23. 173
    Walter Crain says:

    hank @ #163

    i understand how the US could be cold and the globe warm, but over the course of a century? also, he was just comparing class 1 stations vs all stations in the US. the rate he found was less than 25% of the rate given here:
    https://www2.ucar.edu/climate/faq/how-much-has-global-temperature-risen-last-100-years

    i’m just wondering where the “trick” is.

  24. 174
    Hank Roberts says:

    If someone does look further into Chen and Tung, I’m curious whether their work will appear here:
    http://www.argo.ucsd.edu/Argo_research_in_press.html

  25. 175
    Tony Weddle says:

    Wili, thanks for the link to Ozzie Zehner’s talk. It’s a couple of years old, I think but well worth a watch. I’m glad I held back on installing solar.

  26. 176
    GORGIAS says:

    “The natural variability of climate could be playing a big role. The Pacific Ocean, in particular, oscillates in ways that can strongly influence the temperature of the atmosphere. The cycling between El Niño and La Niña conditions is one of those oscillations, and over the past decade or so, La Niña, which has a cooling influence on global climate, has predominated.”

    -New York Times

    The Natural Variability (NV) card has been played like a God of the Gaps argument by contrarians since the dawn of the discussion.

    Maybe I have missed something but it has always been my understanding that NV is somewhat synonymous with background noise and explains short term trend anomalies. But is there more to it? Can NV have a significant negative effect (if any) on the energy trapped by the greenhouse effect, be the cause of temporary less forcing or more outward radiation into space?

    Or does NV simply have an effect on temp measurements at a specific time or a specific period where the net forcing is still the same but energy (heat) is distributed anomalously?

  27. 177
    Dave Peters says:

    Paul (@ 103)

    I took a few shots, but then side-tracked to a very lengthy, 3 volley exchange with Lord Monckton (9/10ths down-thread, page 1). I have gotten the impression that he played a roll of some significance in overturning the tax regime enacted in Australia. (Mr. Larson?) He was the keynote speaker last month at the minimalist confab in Las Vegas, and is arguing the same point, which Dr. Lindzen offered as a graphic, in the January discussion session with Christy & Curry @ the APS.

    In so far as I know, no one has publicly critiqued that graphic, or argument. I think I did a credible job parrying Monckton’s assertion that science is incapable of assessing feedback and sensitivity, but both his and Lindzen’s feedback criticality argument I just don’t grasp, cannot restate, and cannot rebut.

  28. 178

    #173–Walter, I had a quick look at the article that’s up. One of the commenters makes the point that the variability and trend appear to make the latter statistically insignificant. I’m no statistics whiz, but the point appears valid: the analysis reports a standard deviation of .66, with maximum and minimum trends of 1.18 C/century and -1.93 C/century.

    Apparently, the 23 stations by themselves are not enough, and what the paper proves is that if you look at small enough data sets, you can reach conclusions that are effectively meaningless.

  29. 179
    James McDonald says:

    A technical question:

    Added heat in the atmosphere is presumably causing it to expand.

    But wouldn’t the increasing amount of reflected IR also cause a very minor expansion due to the momentum transfer of the reflected IR photons?
    (More photons bounced back downward would mean more upward momentum on CO2 and H2O molecules…)

    Can anyone here quantify that effect, even to within an order of magnitude? E.g., is the radiation pressure contributing closer to one-thousanth or one-billionth of the expansion caused by thermal expansion?

    Someone asked me and I didn’t have a simple answer except to surmise the effect is rather small.

    Thanks in advance…

  30. 180
    James McDonald says:

    A technical question:

    How much is the atmosphere expanded by the added direct radiation pressure from increased reelection of IR photons back towards the surface?

    How does that compare with the thermal expansion?

    I’m guessing the radiation effect is very small by comparison, but how small? One thousandth? One billionth?

    Thanks in advance…

  31. 181
    Hank Roberts says:

    > 23 stations by themselves

    Chuckle: ‘oogle this:

    when we publish, we’ll have a set of 80 “clean” U.S. stations (out of over 1200) that contain what I refer to as the “true signal”

  32. 182
    Walter Crain says:

    thanks, all of you guys, for the comments on the ron clutz (poor guy) paper (starting @150).

    i guess the bottom line is that the analysis IS valid, but the uncertainty due to the small sample of stations makes the result meaningless?

  33. 183
    David Miller says:

    #170 – bjchip

    It’s my understanding that Tamino got a job offer he couldn’t refuse and moved from Maine to Southern California.

    I expect that between the move and the new job he’s much busier. It’s a shame, I was a regular reader too.

  34. 184
    Chris Dudley says:

    The University of Sydney has become the first institution of its type in Australia to halt further investments in coal mining. http://www.smh.com.au/environment/climate-change/sydney-university-creates-waves-with-investment-ban-on-coal-20140826-108ecj.html

  35. 185
    MARodger says:

    Dave Peters @177.
    You talk of “a graphic” yet there were actually quite a few ‘graphics’ presented in Lindzen’s APS testimony (pdf of the whole APS event here). Was there a particular graphic or set of graphics you were referring to? I should say I don’t recall seeing any that don’t have a public debunking (apart from the silly ones).

  36. 186
    David B. Benson says:

    Trash burning worldwide significantly worsens air pollution
    http://www.sciencedaily.com/releases/2014/08/140826121056.htm

    Lots of PM 2.5.

  37. 187
    john byatt says:

    does anyone have an update for 2013 data and any title change info ?

    http://www.realclimate.org/images/model122.jpg

    tks in advance

  38. 188
    Chris Dudley says:

    The global climate campaign 350.org and partners launched a new campaign today urging Pope Francis to divest the Vatican Bank from all investments in the fossil fuel industry and publicly support the growing movement to divest from fossil fuels.

    The petition to the head of the Catholic church reads: “Your acknowledgement of the dire threat of climate change, the Vatican’s efforts to become the first carbon-neutral state, and your dedication to caring for Creation give us great hope. We urge you to use the power of your office to set an example for the world.” http://www.indcatholicnews.com/news.php?viewStory=25437

  39. 189
    Dave Peters says:

    MARogers @184

    The graph I was referring to accompanied Dr. Lindzen’s direct. Today, my computer refuses to retrieve the image. I am 90% confident that the item is his first exhibit, appearing at page 276, line 20 (in blue hypertext as “next page”). It was a schedule of feedbacks, an upward bending curve, and he was asserting that beyond some critical point, an ever so slight mis-assessment would careen away from reality. And, he was asserting that Manabe took the world off on this unnecessary terrifying rabbit run, beginning decades ago, by a comparatively slight, though insufficiently debated error, which ever since has wildly overestimated thermal feedback.

    By the way, thank you for asking (and also for your eternal vigilance). That graphic stopped me in my tracks. I am a generalist, and Lindzen’s caution has been a problem for me for decades. My take is, he has an extremely keen intellect, knows more about the atmosphere than I could hope to gain if given a new lifetime to devote to same, and his credentials speak for themselves. He brings more gravitas to minimalism in his little finger, than a compliment of his fellows, including a handful of the credentialed specimen. When I see his advocacy resembling that of a lawyer serving his brief, it is a great relief, because it gives me a basis for diminishing the credence I give his technical assertions, which frankly, are beyond my capacity to fairly weigh.

    http://google1.aps.org/search?q=cache:rxXfEC2DvHoJ:www.aps.org/policy/statements/upload/climate-seminar-transcript.pdf+lindzen&site=default_collection&clien

    I contemplated posting a query here, back in March, but settled for waiting to see if someone else thought similarly, and whether this new (to me) take drew attention. But then, when it did not, fell back to a silly April Fool’s day comment instead. Now, as I say, Lord Monckton has incorporated this theme in his presence, and he is quite an effective advocate. If, as you gently imply, an extant counter to Lindzen’s APS testimony is at your fingertips, I would greatly appreciate your sharing it.

  40. 190
    MARodger says:

    Dave Peters @189.
    I think you’ll find Lindzen & Monckton are not arguing the same point although both do use a similar graph to present their points.

    Monckton is entirely away with the fairies. His argument is perhaps presented a little more sensibly here on planet Wattsupia (the graph is figure 3 and the case he makes is close by).
    Monckton says in that piece that the record of global climate over the last 800ky (Vostock ice core data) is the behaviour of“a stable circuit. The temperature-feedback loop gain cannot much have exceeded +0.1″ (That is ECS = 1.1ºC or less.) because “Process engineers designing electronic circuits intended not to oscillate adopt a maximum value γ = 0.1 for the loop gain (and usually an order of magnitude below this). Thus, in a stable circuit, everything to the right of the blue line is designed out.” Perhaps Monckton doesn’t understand the word “oscillate” because the recent ice-ages sure look like an oscillation to me. He does a few paragraphs later say the graph “may be the wrong equation altogether” and that there must be a necessary “damping term” but he then uses the graph with its potentially “wrong equation” to insist we must be “well shy” of the 1.0 asymptote and that due to this there is an implied low ECS.

    At the Heatland jolly (amongst all the videos here), Monckton was entirely off the rails with a garbled version saying:-

    “The variation from the 800k year mean in global temperatures is only 1% up or down in absolute terms. Three celsius, that’s all. That’s not the pattern of a strongly feedbacked driven system, is it.
    And so if you look at the feedback equasion here. You have loop gain going horizontally, you have climate sensitivity to a doubling of CO2 going vertially. You see that huge singualrity at a loop gain of one in the output of temperature change. And the fact is that singularity cannot exist in the real climate because once you go above 1 then feedbacks that have previously been driving up the temperature are suddenly going to drive it down. There is no mechanism physically in the climate by which it would do so. They are using, in my submission (any guidance you may like to give me afterwards this I’ll be grateful for): they are using the wrong equation. If they are, then we can establish in theory as well as by measurement thet the maximum climate sensitivity you are likely to get from a doubling of CO2 is just one celsius.
    So if anyone can clarify that point, we’d be grateful.”

    Myself, I would pay Monckton no heed. As the above amply demonstrates, he spouts gobshite from dawn to dusk.

    Lindzen’s version(s) I will consider later.

  41. 191
    Hank Roberts says:

    > James McDonald
    > … added direct radiation pressure from increased reelection
    > of IR photons back towards the surface?

    I’m not a physicist, but I think that’s not what happens.
    Photons are not “reflected” (I assume that’s what you meant).
    So there’s no “solar sail” light pressure effect pushing the atmosphere away from the Earth due to the increased warmth of the surface.

    Photons are emitted randomly in all directions.
    The molecule absorbs and loses energy — and occasionally, if it doesn’t lose energy by collision first, some part of it wiggles in such a way that a photon gets emitted — in some random direction.

    The above is, at best, bad poetry not physics. The first link on the right sidebar — AIP — under the Science Links heading is a good place to start for clear English explanations of how the physics works

  42. 192
    James McDonald says:

    Hank, thanks for the response, but my question stems from a simple view of the aggregate energy and momentum.

    In scenario A (no greenhouse gases), all of the IR photons escape directly to space.
    In scenario B (some greenhouse gases), some of the IR photons return to earth and are absorbed there.

    One of the differences between A and B is that the momentum of those returning IR photons has been reversed.
    There must then be a corresponding counter-movement by something else (presumably the atmosphere) to balance that.

    I agree that individual CO2 molecule absorb and emit in all directions, but we still need to account for the aggregate conservation of energy and momentum. In particular, the assumption is that the CO2 molecules, on average, absorb more photons coming from below but emit equally in all directions. That creates a net asymmetric upward push on the greenhouse gas molecules.

    Hence my question: how big is the net outward impetus to the atmosphere due to the change in IR momentum between scenarios A and B?

    I think I could calculate an approximate answer myself, but (a) I’m not that familiar with the details, and (b) simply don’t have the time to work out the answers to every question that occurs to me.

  43. 193
    David B. Benson says:

    Nanodiamonds are forever: Did comet collision leave layer of nanodiamonds across Earth?
    http://www.sciencedaily.com/releases/2014/08/140827163443.htm
    Clovis comet redux.

  44. 194
    Hank Roberts says:

    > That creates a net asymmetric upward push

    You’re beyond me. Is that an assumption, an observed behavior, or a measurement?
    The radiation physicists will notice the question if it’s interesting, I imagine.

  45. 195
    Chris Dudley says:

    James (#180),

    In an opaque medium, radiation does contribute to pressure as you suggest. But where as gas pressure is proportional to temperature multiplied by density, radiation pressure is proportional to the forth power of the temperature. By considering that radiation pressure only contributes a lot to the interior pressure of very massive stars and only a little in the interior of the Sun, at our temperature it should be insignificant.

    It is interesting to note that in very massive stars, the temperature is so high that gamma rays of the same energy as the rest energy of electrons are part of the thermal spectrum. Because radiation pressure is dominant, creating pairs of electrons and positrons using these gamma rays can cause a sudden reduction in pressure (usually more particles means more pressure). That reduction is pressure is followed by a sudden gain in density and a nuclear fusion explosion that can completely disrupt the star in what is called a pair instability supernova.

    Your question leads to some very interesting physics.

    There is a web site to calculate it: http://hyperphysics.phy-astr.gsu.edu/hbase/starlog/staradpre.html For 300 Kelvin it is 2 time 10^(-11) atm.

  46. 196
    MARodger says:

    Dave Peters @189.
    Picking up on Lindzen’s use of the graph, you questioned @177 whether anyone had “publicly critiqued that graphic, or argument” which I read a little different to an “extant counter to Lindzen’s APS testimony” that you ask about @189. (I took it to be the-pair-of-them’s graphic but only Monckton’s argument.)
    My comment presented @185 was simply that there were no graphics that I recalled in need of a critique. Now that we both have the one graph in mind, Lindzen’s “Response as a function of Total Feedback Factor” graph, (it’s on p279 of his APS testimony) I would say the graph itself only has one feature requiring a critique. That is, for some reason it shows ECS=1.25ºC for zero feedback. I would assume this is down to a slip-up in X-axis labelling.
    I should say that the annotations are another thing entirely.

    However, looking at the bit of Lindzen’s APS testimony that uses that graph, as I said @190, this is a lot different to Monckton’s nonsense key-note comment at the Heartland jolly.

    There is however a possible connection with Monckton in that the graph did see light of day in a talk Lindzen did (PDF of slides) within the House of Commons in Feb 2012. (The talk was also videoed Part 1, Part 2 (not working just now) and the Q&A session.) And in this HoC talk, Lintzen came close to Monckton’s nonsense. Lindzen is using his graph (p53 of the PDF linked above) to say that high Feedback Factors above 0.5 (ECS = 2ºC or more) are unlikely because over the history of the Earth small changes in ECS would have occurred boosting it higher and this would have caused Feedback Facors of +1.0 and thus run-away climate change. This would prevent us being around to discuss it. As that hasn’t happened and we are here, ECS must be lower than that (whatever “that” is). (Note the graph annotations point to a different use for the graph.)
    Of course, such an argument manipulates the ECS formalism beyond all credibility. For instance, it relies on the ECS formalism for today’s climate continuing to apply for ever-increasing (/or decreasing) temperatures, something which surely doesn’t happen. Feedbacks from the likes of ice albedo rely on there being ice to melt (/or fresh ground that can be covered in ice) which would at least require a freezing temperature to cease (/or to start to occur) at various latitudes and in various seasons. Yet an ice-free Earth has happened, as has a slushball/snowball Earth, both bringing a limit to the action of an ice-albedo feedback. And most other feedbacks will be to some extent or other similarly temperature-dependent.
    So I would suggest that Lindzen’s talk at the HoC was making here a throw-away comment of, I would argue, zero merit. (Mind, some of his other comments in that talk were down-right scurrilous.)
    And the connection to Monckton’s Heartland nonsense is reinforced as this HoC talk was organised by none other than Monckton. And thus Lindzen’s talk could have been the genisis of Monckton’s nonsense as described @282.)

    At the APS, Lindzen is making a different point. He is addressing the question “what gives rise to the large uncertainties in sensitivity? “ (Given its annotations, this appears the true purpose of the graphic.) His comment is that the existance of water vapour as a large positive feedback mechanism increases the sensitivity of the climate “system” to further feedbacks. “The point is, it is the existence in the models of a basic positive feedback that leads to the uncertainty. “(My emphasis.) This, of course, is system talk not real-world talk and so it’s not actually answering the question which was a real-world question.
    It is also a poorly developed argument. If the climate is more or less sensitive to forcings, all that changes is the ratio Δtemp/Forcing. But what has changed in establishing ECS? Establishing Δtemp and Forcing with more accurately remains the nub of the problem. If Lindzen had stuck to expressing Forcing as W/M^2/ºC instead of Feedback Factor (an engineering concept) the confidence limits would plainly remain proportionately large whatever the ECS. Using an inverse-exponential scaling on your graphs won’t reduce real-world confidence limits.

    The full argument that Lindzen then leads on to at the APS takes no account of the science as a whole and presents solely the answers according to Lindzen. These ‘answers’ have already been given a good kicking at Skeptical Science and for some reason it is the earlier 2009 reference that is given the treatment in IPCC AR5 Section 10.8.2.5. That leaves the one unturned stone which is the latest paper Lindzen referred to Choi et al (2014) (Abstract) For some reason it hasn’t yet resulted in any commentary that I can find. But on the strength of past performances, don’t expect anything ground-breaking to crawl out from under it.

    And a final thought, you do say @189 ” That graphic stopped me in my tracks.” Is that still the case?

  47. 197

    #192 et rel., and especially #195–

    All this is perhaps a tad esoteric, but interesting for this Bear Of Very Little Physics And Math.

    Chris D’s response at #195 is helpful. But I still had some thoughts.

    “In scenario B (some greenhouse gases), some of the IR photons return to earth and are absorbed there.”

    But that’s not the end of the story, is it? Those IR photons absorbed raise the temperature, and hence increase radiative efficacy (a concept I understand much less well than I’d like.) That’s the Planck (negative) feedback. Some of the energy is diverted, to be sure: thermal energy subducted through mixing of ocean or lake waters, an even smaller proportion taken up via photosynthesis to create the biosphere (or most of it, anyway, remembering that there is chemophilic life.) But just a tiny proportion. Is that proportion relatable in a reasonable way to the radiative imbalance shown to exist? (I’d tend to think that if it were large enough to be so related, it would show up in modern energy budgets–but it doesn’t.)

    “In particular, the assumption is that the CO2 molecules, on average, absorb more photons coming from below but emit equally in all directions. That creates a net asymmetric upward push on the greenhouse gas molecules.”

    Seems like a very dubious assumption. First, how meaningful is ‘on average’? One of the big points to remember is that it’s not a slab atmosphere; altitude matters, a lot. GHG molecules near the surface will receive nearly the same radiation from above as from below. (Of course, one would want to quantify that–presumably the lapse rate compared with the optical thickness would be the biggest thing to look at.) But ‘near the surface’ is just where the biggest proportion of molecules is found. It would seem that that should limit (though not eliminate) the effect. Second, I think that the spectral details would probably end up mattering a lot, as would relative abundance of gases at various altitudes.

    “The chemical composition of the troposphere is essentially uniform, with the notable exception of water vapor. The source of water vapour is at the surface through the processes of evaporation and transpiration. Furthermore the temperature of the troposphere decreases with height, and saturation vapor pressure decreases strongly as temperature drops, so the amount of water vapor that can exist in the atmosphere decreases strongly with height. Thus the proportion of water vapour is normally greatest near the surface and decreases with height.”

    http://en.wikipedia.org/wiki/Troposphere

    I really have no idea how the influences of those factors would play out. But I have to wonder, is James’s simplification defensible in that regard?

    Just some fun musings. As Hank says, if they are interesting to some, perhaps they’ll be picked up on. More likely, they will be blissfully ignored by all concerned, and no harm done. :-)

  48. 198
    Hank Roberts says:

    From FractalPlanet blog:

    The cooling trend of the last ~6,000 years is actually kind of up for debate, as I recently learned: http://arstechnica.com/science/2014/08/models-challenge-temperature-reconstruction-of-last-12000-years/
    The idea that humans began changing the climate thousands of years ago is Bill Ruddiman’s. He (et al) just published a nice review of that: http://anr.sagepub.com/content/1/2/147.full.pdf+html (open access)

  49. 199
    sidd says:

    “In particular, the assumption is that the CO2 molecules, on average, absorb more photons coming from below but emit equally in all directions”

    Wait, what ? Atmospheric CO2 molecules, say at STP, are moving at a few hundred meter/sec, and vibrating (thats the infra red absorption), and spinning (microwave) have a buncha vib-rot bands, and no clue which way is up, down or any other direction. The will happily absorb and emit in any and all direction. But even without thinking about EM absorption/emission, we know the assumption is incorrect due to kinetic theory and detailed balance considerations.

    If it were correct, from a quick (and possibly inaccurate) calculation, net upward momentum imparted to a CO2 molecule would be around 1 ten thousandth the average translational momentum at STP times the asymmetry per absorption/emission event , which for any noticeable asymmetry would expel all CO2 to space in geologically doublequick time.

    sidd

  50. 200
    Chris Dudley says:

    Kevin (#197),

    Here is a simple version of the problem which is amusing. http://en.wikipedia.org/wiki/Eddington_luminosity


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