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Unforced Variations: June 2011

Filed under: — group @ 1 June 2011

A new open thread…

487 Responses to “Unforced Variations: June 2011”

  1. 251
    flxible says:

    I whole heartedly 2nd SecularAnimists motion @246, the egregious repetition is beyond old.

  2. 252
    dhogaza says:

    EG:

    A nuclear bomb “compresses” pure or nearly pure fissile material into a small space. The fissile material is either the uranium isotope 235 or plutonium

    Since you insist on lecturing as though you’re some sort of expert, Little Boy was a U235 gun design, not a far more complex compression design. This is one reason they dropped it on Hiroshima without bothering to test a prototype first (unlike Fat Man).

  3. 253
    Adam R. says:

    @Patrick: “More generally, any system where energy enters in one form but leaves in another may be subject to a greenhouse effect of sorts, where a mechanism that impedes the flow of one type of energy may change the equilibrium concentration of energy.”

    Wow. That’s a beauty, Patrick–a perfect gem.

  4. 254
    Ron R. says:

    Edward Greisch at 2:36 PM

    Wait a minute. First you said at 12:09 AM,

    I read page 323 of Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII – Phase 2. I didn’t find your quote. So same to you

    Now you say:

    Safari can’t find the server.
    Safari can’t open the page “http://www.epa.gov/rpdweb00/radionuclides/iodine.html#change” because Safari can’t find the server “www.epa.gov”

    I thought you said you read it?

  5. 255
    Walter Pearce says:

    EG@244…I’m sorry, either you’re being mendacious or your reading comprehension has atrophied. The article cited is all about energy infrastructure, of which wind is a part.

    You do recall the subject, I hope?

  6. 256
    Ron R. says:

    OT. Sometimes when I find myself getting really cynical about human nature I read an article like this and it reassures me that there are still good people out there and that there is hope.

    http://www.latimes.com/news/local/la-me-wildflower-20110612,0,3902383,full.story

  7. 257
    Patrick 027 says:

    Re 253 Adam R – thank you !

    Re 252 dhogaza , and EG – as long is this has been brought up, I had been under the impression that nuclear reactors at present depend on a fissile material capable of being made into a density or volume (if the neutron mean free path allows significant escape from the volume than adding volume while keeping density the same would tend to help, right?) sufficient for a chain reaction – given such fissile material, if you can sustain a chain reaction, then you could adjust things to produce more neutrons than necessary to sustain the chain reaction (unless the isotope required is already pure and the volume large, so any increase in density only decreases the mean free path of neutrons proportionally without changing absorption per unit mass…on the other hand, free neutrons decay spontaneously so increasing density wouldn’t reduce the mean free path by quite as much (nit-picking?)) – perhaps leading to exponential growth of the reaction rate (?) – I suppose I must be wrong about that(?), since power plants don’t routinely blow up (but you could have slow exponential growth that can be corrected in time).

  8. 258
    Patrick 027 says:

    … of course I realize there’s something called a nuclear fizzle… (an assemblage could destroy itself before producing enough energy to destroy so much much much more ?? – is that how it works?)

  9. 259
    Patrick 027 says:

    … given that this is a climate blog, loosely an energy blog by tangents, just feel free to give me a website and say nothing more about that… (well I should just go look it up, then, shouldn’t I…)

  10. 260
    Eli Rabett says:

    Pinata’s up. Lindzen and Choi II, the zombie returns

  11. 261
    Patrick 027 says:

    Wrapping up something from the last unforced variation (La Nina, was it?)…

    Δμ is the chemical potential between two populations of electrons (or electrons and holes – however you look at at).

    Fermi function f1(E1,μ1,T1) = 1/( exp[(E1-μ1)/(kB*T1)] + 1 ) for energy E1, quasi-fermi level μ1, and temperature T1.

    Rather than doing more equations, this can be done graphically – the spacing between f1 values over energy E1 is proportional to T1. So for a temperature T0 and quasi-fermil level μ0
    for which the smae f1 value would occur at the same E1 value, E1-μ1 / T1 = E1-μ0/T0.

    So plot E1 and E2 on the E line
    (where f2(E2,μ2,T2) = 1/( exp[(E2-μ2)/(kB*T2)] + 1 )

    plot other lines, the μ1 and μ2 lines, some distance from the E line proportional to T1 and T2, respectively. Plut μ1 and μ2 values along those lines (where E is measured along those lines). Now there’s a temperature axis (equal to zero at the E line) perpendicular to those lines and an energy axis parallel to those lines. f1 and f2 are constant along the lines which intersect E1 and μ1, and E2 and μ2, where each point’s location defines T and μ. Where those lines intersect, f1 and f2 have their original values where T = T0 and μ = μ0. If T1 = T2, then, where E = E1-E2 and Δμ = μ1-μ2, E-Δμ/T1 = E/T0. E and T0 can be input into the exponential term in the Planck function for the emission and absorption by electron-hole pairs between bands 1 and 2 with quasi-fermi levels μ1 and μ2. In terms of photons:

    A = 2*n^2 / (h^3 * c^2)

    βE = A*E^2 / ( exp[(E-Δμ)/(kB*T)] – 1 )
    =
    A*E^2 / ( exp[E/(kB*T0)] – 1 )

  12. 262
    Edward Greisch says:

    [edit – enough is enough. Nuclear is now OT]

  13. 263
    dhogaza says:

    Can’t EG be boreholed?

    Or can’t nuke power issues be put back off-limits at RC as it once was?

    (I guess the debut of unforced variations put nukes back on the table, but really, RC was more readable when nuke power crap was off-limits. the unforced variations threads would be better suited for intelligent discussion of things not brought up by the blog owners, rather than being a “bore hole lite”, though on perusing the bore hole a few moments ago, I’m almost convinced the bore hole has become an “unforced variations” lite …)

    [Response: Every so often, the comments turn to nuclear power issues. Very little is ever learned in these exchanges, and they often become repetitive and tedious. So, yes, this particular conversation is now off topic. There are plenty of blogs where this can be discussed. This is not one of them. – gavin]

  14. 264
    Patrick 027 says:

    … Didn’t see inline response to 263 when I posted my last comment.

    (I hope I can still post general CO2eq/kWh values, which will include nuclear, along with coal, oil, gas, geothermal, hydroelectric, solar PV, wind, ? – I was eventually going to put together a list of references for that to back up what I said earlier. I won’t go on-and-on about it, at least not the details of nuclear.)

  15. 265
    Ron R. says:

    Thank you. I suspect that goes for a lot of other people as well.

  16. 266
    dhogaza says:

    Patrick 027 – Gavin, I know this is off-topic, but Patrick’s asking for clarification, and I’m not speaking to the advisability or not of increasing power generated by fission power plants …

    … of course I realize there’s something called a nuclear fizzle… (an assemblage could destroy itself before producing enough energy to destroy so much much much more ?? – is that how it works?)

    Yes, meltdown or dirty explosion (of very low yield) rather than an atomic bomb, essentially …

    This is why the “gun configuration” doesn’t work for plutonium. The U235 gun configuration of Little Boy depended on a high explosive shooting a U235 bullet at high velocity through a U235 ring and the physics are such that the configuration is stable enough for long enough (microseconds) to cause, well, Hiroshima. Such a design isn’t very efficient, though, even though Hiroshima was horrible. Or beyond horrible … as horrible as it was, though, the energy released blew it apart before anywhere near the full potential energy of complete fission of the U235 could be obtained.

    Do it with plutonium and it deconfigures (low-yield explosion, melt, I’m not quite sure quite what or if it’s even declassified at this point) before it can do the Big Nasty.

    Ironically, purifying U235 is much harder than breeding plutonium, while making a U235 bomb is much easier than making a plutonium bomb (Fat Man).

    Even more ironically, the hydrogen (fission-fusion-fission) bomb’s thermonuclear stage makes U238 a viable bomb explosive … and could be built more or less infinitely large (for at least some values of more or less infinite). The limits here have to do more with tradeoffs between things like how big a launch vehicle can you build vs. how big a boom do you need to destroy NYC or whatever as much or more than physics. Thus Edward Teller’s (and others’) fascination with contrived applications for ever-larger hydrogen bombs.

    Uranium-based power reactors like those in Japan and the US 1) use fuel that isn’t highly purified U235 but rather “enriched U238” (low fraction of U235, though far above that found in unenriched purified uranium) 2) is a static configuration (not brought to critical mass via a “gun” configuration or via explosive compression with no damping to control it).

    Really, the best it can do is melt at a very high temp, burn, cause secondary explosions due to its high heat, etc.

    Even the movie “The China Syndrome” had this right, that refers to a core melting clear through the earth (also silly, one would assume at the very most science-fiction worst it would stop in the earth’s core). But at least they didn’t have it doing a Hiroshima …

    Anyway, hopefully it’s recognized that this has nothing to do with the “nuclear power” question at all (which I’m so happy has been declared O/T for this thread), and you’ll be able to read it after it’s approved …

    [edit – this is absolutely the last word on this.]

  17. 267
    Edward Greisch says:

    [edit – OT means OT, take it elsewhere]

  18. 268
    Clippo (UK) says:

    Re: #256 by Ron R.
    Completely OT but …… In my lovely English Cheshire garden, I have a fine specimen of Carpenteria Californica which is about to burst forth into flower in the next few days. I value it as one of my favourite plants .
    I have tried, not very hard I have to say, to propagate it, but if you think your local population is still at risk, I’ll try harder and send you some cuttings (smile).

  19. 269
    J Bowers says:

    Guardian – Explosion in jellyfish numbers may lead to ecological disaster, warn scientists

    Global warming has long been blamed for the huge rise in the world’s jellyfish population. But new research suggests that they, in turn, may be worsening the problem by producing more carbon than the oceans can cope with.

    Science Daily – Jellyfish Blooms Shunt Food Energy from Fish to Bacteria

    The paper – Jellyfish blooms result in a major microbial respiratory sink of carbon in marine systems. Condon et al (2011) PNAS

  20. 270
    Jim prall says:

    Re: “Safari cannot find http://www.epa.gov
    That sounded fishy, as i know http://www.epa.gpv exists. I happened to be reading this in Atomic Web on iPad, and this alternative browser found http://www.epa.gov just fine. Then that site detected that i was on iPad, so redirected me to their mobile version, http://m.epa.gov
    Ignoring the fact that atomic web promptly quit on opening that page, i looked instead with Safari (iPad) and found the interesting message there that EPA are holding a contest of sorta called “Apps for the Environment” Given the prevalent of programmers and the like here, plus our theme topic, i thought this might be of interest to many readers. Not everyone who programs is set up as an IOS app developer- i believe you basically have to work on a Mac, and need to sign up as an Apple Developer – there could be mobile web-based entries, and many more of us could be consumers and testers of the submitted apps.

  21. 271
    Chris Dudley says:

    raypierre (#202),

    I appealed to your childish side since you would not respond otherwise, for example at dotearth where you first made your error and I promptly pointed it out. If you will now admit that the oceans do indeed absorb carbon dioxide from the atmosphere and will continue to do so at a substantial rate for many decades as your own published work indicates, and perhaps take the time on dotearth to explain to Andy that stabilizing the concentration of carbon dioxide in the atmosphere at 450 ppm does not require cutting emissions to near zero immediately upon reaching that concentration then we’ll have cleared up both the error, and perhaps a portion of its consequences.

    It is difficult to correctly apply the term ‘witless’ to Monty Python allusions. You might want to consider some other insult.

    [Response: The corollary that anyone who alludes to a Monty Python sketch is therefore witty is somewhat hard to agree with. – gavin]

  22. 272
    Radge Havers says:

    More on the dynamics of denial. Claptrap is a shared activity. I’m glad to see this addressed.

    Are Progressives in Denial About Climate Change?

    “…climate change is not just another ‘issue’.”

    Best sound bite I’ve heard all week.

  23. 273
    Ron R. says:

    Clippo (UK) at 3:34 AM.

    Extremely kind of you. I happen to live within the California Floristic Province and very near an excellent “alternative” nursery (my term; I mean that they go beyond the usual fare that you find at, say, Home Depot) that sells them in one, five and 15 gallon sizes. Much cheaper than trying to send them from the UK. :-)

    http://www.conservation.org/explore/priority_areas/hotspots/north_central_america/California-Floristic-Province/PublishingImages/15california_5f02.gif

    Problem is California exploded in growth and development has taken so many beautiful wild lands. This state (my native state) is by far the most populous in the US. I’ve always loved nature but it was watching the depressing, maddening and relentless onslaught on the lands around me that turned me into more of an activist. I’m not as much anymore as I found the the perpetual bad news too depressing. I do like to spend a lot of my free time hiking the hills around me though, imagining a happier time.

    Here’s some beautiful pictures of a lovely flower.

    http://www.crocus.co.uk/images/products2/PL/00/00/00/06/PL0000000691_card_lg.jpg

    http://www.native-again-landscape.com/images/carpenteria-californica-show-set1.jpg

    Again, thank you for the offer!

  24. 274
    Chris Dudley says:

    M (#209)

    Thanks for your questions. On the first one, this arose because Andy Revkin wrongly believed that emissions had to go to zero on a technologically difficult timescale. He cited something raypierre posted earlier on dotearth about bathtubs and then raypierre, surprisingly and mistakenly backed Andy up. Regardless of emissions having to go to zero eventually, on a technologically difficult timescale, they don’t have to be cut all that far. There is no technological roadblock for making adequate cuts to emissions to stabilize the atmospheric concentration of carbon dioxide at 450 ppm. The required cuts still allow room for aviation and some other difficult fossil fueled sectors to continue. They can keep going like that for sixty plus years with a stable concentration of carbon dioxide in the atmosphere. Sixty plus years means a plethora of technological miracles without even trying. We don’t even call such things miracles actually. Are the CAFE standards a miracle? So, the 18% is unimportant from the standpoint of policy relevance.

    I would say that in a stabilized atmosphere, the stock in the atmosphere remains constant (by definition) rather than dropping. It is the stock in the oceans which is rising to equilibrate.

    On your first code question, b represents the growth in concentration (times 4.36 to pass through 270 ppm in 2000. e is a silly step since it also grows at 2% but with the factor of 4.36 is is within a factor of two of actual emissions (in concentration units). Another factor of 2 and we are at emissions per year.

    On your second code question, I am using arrays and accumulating in d. For each year’s emissions e(i) their contributions to all future years are accounted for in one step by adding the array c.

    You can run the code using the Fawlty Language. http://fl.net23.net/

    (A very indirect Monty Python allusion I see, but then NOBODY expects it.)

  25. 275
    Chris Dudley says:

    M (#210),

    I used the Kharecha and Hansen figs. 3 and 4 to identify what level of emissions stabilize the concentration of carbon dioxide in the atmosphere. You’ll note that in every case where stabilization is achieved, it is subsequently lost because the concentration begins to decline. Thus, the emissions are too low to maintain stabilization. Their fig. 7 is closer to my calculation though their cuts are latter.

    I agree that their eqn. 1 is a fit but it seems to give results that agree with Solomon et al. and raypierre’s NRC report. In terms of carbon cycle feedbacks, I think a 350 ppm target would be the most prudent at this time. From a moral point of view, 280 ppm would be best.

  26. 276
    M says:

    Dudley’s early posts seems to suggest that he thought that we could stabilize emissions at 50% of present in order to stabilize concentrations at 450 ppm, with statements like “no further research into alternative energy sources is required to stabilize the concentration of carbon dioxide.” Now, his goalposts have moved, and he is saying instead something about as obvious as 2+2 = 4, namely that “stabilizing the concentration of carbon dioxide in the atmosphere at 450 ppm does not require cutting emissions to near zero immediately upon reaching that concentration”. The first statement: wrong. The second statement: obvious.

    “we’ll have cleared up both the error”
    The only error that requires cleaning up here is Dudley’s own confusion.

  27. 277
    vukcevic says:

    My effort during last year or so has produced some interesting results:
    http://www.vukcevic.talktalk.net/A&P.htm
    Regarding PDO, my data is by no means perfect, but considering large discrepancy in 1950-60 decade, I searched for a reason why PDO may had a half aborted cycle, could not find one. This was time of nuclear tests in Pacific but that appear to be unlikely cause.
    Would appreciate link to any paper that may looked into this ‘anomaly’.

  28. 278
    Edward Greisch says:

    262 edit: “Nuclear is now OT” except for 263 dhogaza, 264 Patrick 027, 266 dhogaza
    The editor is not unbiased.

    [Response: The editor is tired of this. – gavin]

  29. 279
    ccpo says:

    Dudley, I am always surprised by people who 1. do not understand risk assessment and 2. do not understand tipping points/non-linear responses.

    Please, read slowly. Risk assessment is not concerned with what is most likely so much as it is concerned with what will cause very great harm. It deals with the unexpected, the long tails, the fat tails, the things we think will only happen to the other people in the world, but not ourselves. Let us take a simple comparison.

    For our homes, be we homeowners, we do not take out old paint insurance, collission with the moon insurance, or neighbor dog peeing on the siding insurance or my fist through the door insurance because the first is just not a big enough risk, is expected, and can be done yourself fora few cans of paint; the second will just never happen; the third is not going to harm your house and the last might happen often, but, really, you can’t insure against whacking your own house – it’s fraud.

    We do tend to insure against fire, flood, earthquake, etc. Why? Because these events will likely never happen to you (well, unless you just didn’t think when buying your home), but if they do, they can destroy the house and/or kill you. The risk is too high *not* to insure.

    You follow?

    Now let’s make a little grid. We have climate change do nothing and climate change do something on one axis and not real and real on the other. Our choices look like this:

    do nothing/not real
    do nothing/real
    do something/not real
    do something/real

    Let’s look at outcomes.

    do nothing/not real: life goes on with the pollution, inefficient use of fossil fuels, which we will still run out of someday, but unprepared for because, hey, we don’t need renewables!

    do nothing/real: We all die. Literally. Eventually. 6 degrees and all that. A few stragglers up in the Canadian Archipelago, I suppose. Eating lichen.

    do something/not real: We get cleaner energy, a cleaner environment, a sustainable economy, better communities. Yay!

    do something/real: We get cleaner energy, a cleaner environment, a sustainable economy, better communities. And, SAVE THE WORLD! Yay!

    See? Three out of four outcomes are GOOD for us. Only “do nothing” has a really nasty ending, so how about let’s not do that?

    When you say we, gosh, have time to hang out at 450 for a while you are ignoring that there is research out there that says Greenland might melt significantly at as low as 400ppm CO2. You ignore that things are moving very, very quickly already. Arctic Sea ice is already melting away. Etc.

    You are playing with fire. Please don’t do that with my son’s life. There is only one sane approach: get to a sustainable state as fast as is humanly possible; heck with the torpedoes, full steam ahead!

  30. 280
    Michele says:

    @ 213-219 Patrick

    I agree with you the problem is more complex than I am representing it but it is indisputable that:

    1) The lapse rates are quit identical. The mentioned profile tell us that the temperature passes from 310 K to 260 K while the height passes from 52.5 km to 58 km, that’s, the lapse rate is 50/5.5=9.4 K/km. The dry lapse rate for Earth is 9.81/1.005=9.76 K/km and for Venus (g=8.87 m/s², Cp=0.846 kJ/kgK) is 8.87/0.846=10.5 K/km. Assuming a range of ±5%, we could claim that they are equal!

    2) If we take away as much of the Venus’ atmosphere as there is needed because the pressure at the ground becomes one bar (as it is for Earth), that’s, if we cut off all the pressure profile below circa 50 km, the surface temperature would be approximately the same than the Earth’s one, although the immeasurable difference of the C2 densities.

    At a first glance, it seems that we should seek the answers elsewhere.

    @ 243 Chris Colose

    You are right, the matter needs to be treated deeper. I am waiting for.

  31. 281
    Chris Dudley says:

    M (#277),

    You have misread what I wrote. I wrote 50% of 2000 emissions. That continues to be the case. We can stabilize the concentration of carbon dioxide at 450 ppm using current technology and continue to do so for sixty plus years. No goal posts have been moved except mistakenly by raypierre.

  32. 282
    Snapple says:

    I have been reading about the St. Petersburg Flood Prevention Complex.
    http://en.wikipedia.org/wiki/Saint_Petersburg_Dam

    Here is a sketch:
    http://en.wikipedia.org/wiki/File:Spb_kronshtadt.svg

    St. Petersburg floods all the time because much of it is very low. Some people think this dam will prevent flooding, but others think it could trigger storm surge.

    Also, does anyone know if climate change will affect the clonic low pressures that are said to cause the flooding.

    Here are some Russian opinions.

    http://legendofpineridge.blogspot.com/2011/01/russian-media-moves-to-calm-junk.html

  33. 283
    Chris Dudley says:

    ccpo #229

    You should really get after raypierre for proposing 560 ppm rather than me if you are going to follow the idea that discussing a stabilization target implies support for that target. However, a 450 ppm stabilization target remains a diplomatically important target since European emissions commitments are aimed towards that target. It is worth discussing how that is achieved. Contraction and convergence is the mechanism envisioned and that implies that developed countries will cut emissions 80% while developing countries will not cut emissions but will neither increase their emissions so much that a 50% cut from some year’s emissions(usually 1997) will be the world target. The idea is to even up per capita emissions and this is tied to millennium development goals. You can see an emissions profile that is a bit optimistic about China’s performance here http://en.wikipedia.org/wiki/Contraction_and_Convergence

    On moral grounds, I support a 280 ppm target. I think that that target can be justified on scientific grounds as well in an interesting manner. It is too late to discuss the ethics of carrying out an experiment on the composition of the atmosphere for this run, but if we are to consider what we are doing a climate experiment, then the only way to allow for reproducibility is to reset the system to its original state while preserving some fuel to allow the experiment to be run again. Since some fuels are already facing shortage, it is time to put our efforts to shutting down this run and soaking up the excess carbon dioxide so that we may have an ethical discussion about repeating the experiment from the comfortable initial condition of 280 ppm. I would suggest that at that time, the same arguments that would bring a failed drug safety trial to an early end would be applicable to considering a second run of a carbon dioxide experiment. But, we can’t even have that discussion if we don’t design our first run to allow for reproducibility which is something we can still do if we act quickly.

    Climate engineers may take a different view of course.

  34. 284
    ccpo says:

    Chris, glad you are looking to 280, but you and Ray are wasting your time splitting hairs. If what we do does not match the risk assessment, it is a waste of time unless we just get lucky. The worst case is what you insure against, the best is what you hope for. In the case where practical limits to action prevent preparing for the worst case scenario, you still shoot for as close to that as possible. When it is relatively simple to meet the goal, it’s rather insane not to. That is the case here.

    The worst case scenarios are well-represented, imo, by the MIT modelling and Hansen, et al.’s 400 ppm as the lower boundary for significant GIS melt, as well as the simple observation that both Greenland and Antarctica started melting well before we hit 400 ppm, as did the permafrost and clathrates. What, then, is the point of discussing anything over 400 ppm? When we add in how simple it is to reduce carbon emissions, all the more so.

    Hansen’s recent The Case for Young People suggested the rebuilding of forests as a way to get to net zero emissions when combined with controls on emissions. This is a simple thing that can be done all over the planet. If it is limited to rebuilding ecosystems that have been destroyed, then the concerns expressed by, I believe, Gavin or Jim, in earlier threads that adding in billions of trees may do strange things to climate, also, should be reduced. However, the work of Mollison indicates a good understanding of the roles of trees and forests on winds, hydrology and temperatures, so I am fairly certain we can make safe choices wrt location and extents of reconstituted forests, or even new forests. If, for example, the global choice is not to cut emissions so much as mitigate them (not my recommendation because of other ecological services and resource limits issues), then more forests will be needed, but, again, we can make fairly good predictions as to what the effects of new forests will be. if we screw up, they are easy enough to cut down.

    A simpler option with nothing but positive side effects, imo, is to shift all farming and gardening to regenerative practices. Regenerative practices turn gardening and farming into carbon sinks by sequestering large amounts of organic material in the soil.

    http://www.ifoam.org/growing_organic/1_arguments_for_oa/environmental_benefits/pdfs/Rodale_Research_Paper_Regenerative_Agriculture.pdf

    They have the added benefits of healthier, more nutritious food, eliminating the use of fossil fuels in food production, being simple and accessible techniques anyone can apply anywhere, reducing water use, encouraging a greater connection with our natural cycles, enhancing resilience in the food system, etc.

    Simply changing current global cropland to regenerative practices can sequester up to 40% of current emissions. The combination of reforestation (not tree planting), many of which can be food forests, greatly stabilizing food supply while reducing significantly energy inputs, and regenerative agriculture with some reductions in emissions not only will solve the CO2 problem, but actually allow us to return to below 300.

    Why waste time on non-solutions that may mislead some to believe what is unsafe is safe?

  35. 285
    Chris Dudley says:

    ccpo #284,

    As I said, 450 ppm is a common focus of discussion. And, there are some who mistakenly say that it is too difficult to achieve and so we should do nothing. My interest here is to remove inaccurate support for the idea that it is too difficult to achieve. Thus, I feel quite OK about discussing it.

    I think you should be a little careful when looking at the Greenland Ice Sheet. Overshoot may be acceptable in that case if it is sufficiently brief. In Hansen et al.’s paper on targets they accept some overshoot for the 350 ppm target, wanting keep it under 100 years. They also suggest fine tuning based, primarily, on ice sheet behavior. You need to work out what you mean by 400 ppm as a target. Will there be overshoot? Will it be contingent? How do you persuade diplomats to negotiate commitments when you may pull the rug out from under their feet in a decade? 350.org has similar but less pressing problems since it takes a while to get back to 350 ppm. Probably 350.org is in a more practical position.

    One final thought. A 350 ppm target with less than 100 years of overshoot can be accomplished without any assistance from transformed agriculture by the use of military force. A hegemonic power or alliance could blockade oil, gas and coal exports along with energy intensive goods exports while saving its own emission cuts for last. Imposing a 20% annual cut in world emissions down to zero does the job without any intentional sequestration.

    Such an effort was an early response to slavery. England, in particular, attempted to bar by force the transport of slaves by sea. That was to end the trade, but not slavery itself.

    In some ways, I feel that by advocating a target of 280 ppm, I am more like an abolitionist who still does not see the horror of the Civil War beyond the horizon. But, while a 350 ppm target could be imposed unilaterally by force, a 280 ppm target would require a lot of cooperation I think. While the threat of force stands behind most diplomacy including climate negotiations, it may not for a target of 280 ppm.

    Global warming is being seen increasingly as a national security issue in the US with a close look being taken at potential deployments in response to refugee crises, base vulnerabilities and consequences of greater naval activity in the Arctic. The Janus link between diplomacy and force may become more apparent in the fairly near future.

  36. 286
    ccpo says:

    http://theconversation.edu.au/climate-change-is-real-an-open-letter-from-the-scientific-community-1808

    “Beginning today, The Conversation will bring much-needed and long-overdue accountability to the climate “sceptics.”

    For the next two weeks, our series of daily analyses will show how they can side-step the scientific literature and how they subvert normal peer review. They invariably ignore clear refutations of their arguments and continue to promote demonstrably false critiques.

    We will show that “sceptics” often show little regard for truth and the critical procedures of the ethical conduct of science on which real skepticism is based.

    The individuals who deny the balance of scientific evidence on climate change will impose a heavy future burden on Australians if their unsupported opinions are given undue credence.

    The signatories below jointly authored this article, and some may also contribute to the forthcoming series of analyses.

    Are you a scientist? Do you agree? If you’d like to add your name to the list, send an email to megan.clement@theconversation.edu.au

    Perhaps you gents should sign. I hope you will consider it.

  37. 287
    Patrick 027 says:

    Re 280 Michele – Part I

    1. While the dry adiabatic lapse rates on Venus (at least for some of the atmosphere – I think the gas may be somewhat less than ideal near the surface (?)) and Earth, in terms of -dT/dz through a well-mixed layer, are similar (according to your info; I haven’t checked it recently), I still felt it was important to note that they could easily be different among different planets. Also, the latent heating in Earth’s troposphere brings the environmental lapse rates down to around moist adiabatic, although that itself is temperature dependent; there are weather, regional/latitudinal and seasonal/diurnal variations in convection and solar heating and the lapse rate varies a bit and can be stable; I think something around 6.5 K/km can be considered ‘representative’.

    2. It’s an interesting thought experiment to compare the effects of:
    A. keeping the total optical thickness constant but halving the mass of the atmosphere;
    B. keeping the mass of the atmosphere constant while halving the optical thickness (aside from direction and amount of change, approximately what we’re doing on Earth)
    C. keeping both proportional while halving them.

    – in all cases, maintaining constant (average) molecular mass and specific heat of the air.

    For A, if you keep the optical thickness constant, then I think you could maintain the same radiative-convective equilibrium profile if you double the adiabatic lapse rates to account for having a troposphere half as thick. Since this doesn’t happen, the surface must be cooler because otherwise too much radiation would be emitted from the upper troposphere. Of course the tropopause height may also change … (?)

    (this is, in isolation, the effect of pressure. But note that if you remove all greenhouse effects, the pressure no longer shapes the surface temperature, at least not in any simple global average way independent of diurnal and seasonal cycles and mechanical energy inputs such as from tides (doesn’t really matter much directly for at least either Earth or Venus’s atmosphere, but I mention it to be more complete for these hypothetical scenarios) – because you would then need those things to have anything like a troposphere in that case, and that might not be sufficient(?).

    PS haven’t taken into account the concentration of direct solar heating on a smaller mass of air – the stratosphere should tend to warm – but the concentration of greenhouse gases should balance this effect – at least in the skin layer… need to think through some more… Okay then…(?)

    For C, the surface should tend to cool more than in A because now more radiation is escaping to space from the surface and/or the lower warmer layers of air.

    The change from A to C is the same type of change as in B.

  38. 288
    Ric Merritt says:

    My comment a few days ago was phrased a little sharply because the question is deep and the discussions here are often quite shallow. Many of the comments sound naive to anyone who has spent some months on, say, The Oil Drum, following some of its wide-ranging links, which have common themes but no single house ideology. (It’s not the only source, but it’s an excellent place to browse.) Commenters here are quite hard on those who seem to type before reading, and many of us are guilty.

    The question I mean is how we might maintain a materially rich (preferred by most) and radically interdependent world civilization while the fossil fuels that built it go away. Simple solutions along the lines of hey, just use less of the bad stuff and more of the good ignore the dominant feedbacks throughout the world economy, not to mention human behavior. You need to be curious enough about that to at least acknowledge that a proposed world running mostly on renewables (or other fuels I won’t mention to avoid annoying the moderators) is so different from the current one that how it might work is very, very hard to imagine.

    Actually, it’s quite easy to imagine an economy limping from oil shocks, a population continuing to increase by 75+ M/yr, investment suffering, political divisions and wars increasing, and the climate not helping at all. If investment in renewables falls behind what is required, we will encounter vicious circles that are more powerful than the virtuous feedbacks we’d like to see. That would cause the economy, as usually defined, to decline for a very long time. Large projects of any kind would become less likely, not more.

    When I see someone gushing about the vast amounts of energy available from the sun (and the wind etc it powers), I feel discouraged. The amount of energy or power, while of some interest, has in general little to do with how easy or hard it is to run advanced civilization on that source. What we know for sure is that fossil fuels are marvelously energy-dense (put in that state for free, without investment by us, with the concomitant increase in entropy somewhere else), and other sources are far more spread out, thus harder to harvest. You have to do all the harvesting work and then see what is left over to do work outside the energy industry itself. I know the readers here are savvy enough to acknowledge that when challenged, but your comments very often sound like it isn’t even an issue important enought to worry about. That’s wrong.

  39. 289
    Septic Matthew says:

    Declining solar activity?

    http://www.space.com/11960-fading-sunspots-slower-solar-activity-solar-cycle.html

    If the solar evolution progresses as predicted (or at least anticipated) here, diverse climate models will make very divergent predictions for the next 3 decades. The understanding of the climate system should be much more complete and accurate by then.

    288, Ric Merritt: Many of the comments sound naive to anyone who has spent some months on, say, The Oil Drum, following some of its wide-ranging links, which have common themes but no single house ideology. (It’s not the only source, but it’s an excellent place to browse.)

    That’s the nature of a medium devoted to many short posts. Most readers and writers here have deep and well-informed opinions on most topics, but our information bases do not always overlap completely, or we give different amounts of weight to different facts or hypotheses. To me, the best approach is to address “comments” rather than “persons”.

    Consider solar again. Sure it’s a diffuse resource, but electricity is used in a distributed manner. Solar electricity generation technology is getting better and better, and there are millions of acres of empty rooftops and uncovered parking lots yet to be enlisted. For the next few years the US (and other places) can do very well to invest in solar generation to meet peak capacity, improve the technology, and to improve the manufacturing processes. Only if someone writes, or seems to write, that solar has to do everything all at once does solar look like a foolish idea.

    Something similar can be said about wind: technologies and manufacturing are improving, and the costs 20 years from now will be much reduced (if the history of every other technology is a guide.) Right now, wind generation capacity is mostly not close to where the electricity is to be used, but the obvious solution (again with many historical precedents, such as Rochester, NY) is to move the factories to the energy sources. Wind looks foolish only if someone writes that it is a panacea to be adopted immediately.

    Don’t forget, your short comments will appear naive to some readers.

  40. 290
    Ric Merritt says:

    My previous comment got a little long without replying to any specifics, though some have been offered that address the question at least a bit.

    The “solar breeder” (Saharan sun used mostly in Europe) linked by SecularAnimist would certainly be really cool if it happens and works. I gather the planners do aspire to create renewable infrastructure from renewable power. More power to them if they can turn that vaporware into hardware. Even if the technical stuff pans out (a big question), success would imply a regional political arrangement comparable in size, duration, and complexity to the one currently supporting oil from the Middle East. The old arrangement on the way down would be a formidable competitor to the new one on the way up. Impossible, maybe not. Daunting and fragile, for sure. Dependent on large investments to grow quickly, so improbable except in a growing economy. (There does seem to be some kind of claim that the project would grow quickly without significant outside investment, using its own profits, but I don’t think I believe that one.)

    The Scientific American article linked by Walter Pearce will be familiar to many readers. It is very sunny, in every sense, but awfully short of detail, or of any sense of how we are doing so far (too slow for optimism, I would say.)

  41. 291
    SecularAnimist says:

    Ric Merritt wrote: “… a proposed world running mostly on renewables … is so different from the current one that how it might work is very, very hard to imagine.”

    With all due respect, I would suggest that the problem lies in the difficulty that you have imagining something other than the current fossil fuel-based paradigm, rather than any actual material difficulty with running a technologically advanced civilization on renewable energy.

    Ric Merritt wrote: “… other sources are far more spread out, thus harder to harvest …”

    That’s a non sequitur. Wind and solar energy are abundant and ubiquitous, yes. That doesn’t make them “harder to harvest”. On the contrary, they can be harvested readily and easily, in large quantity, almost everywhere in the world, using easily replicated, mass-produced, increasingly cheap technology.

    Ric Merritt wrote: “You have to do all the harvesting work and then see what is left over to do work outside the energy industry itself.”

    I’m not sure what you are saying, but if you are suggesting that it takes as much energy to build and deploy wind farms and solar power plants as they generate over their operating lifetime, that’s very, very wrong.

    Ric Merritt wrote: “… we might maintain a materially rich (preferred by most) and radically interdependent world civilization while the fossil fuels that built it go away …”

    It’s worth mentioning that a tiny fraction — perhaps a few percent — of humanity enjoys a “materially rich” lifestyle.

    For example, there are many, many millions of people who lack any access to electricity at all. For those people, a few solar panels, a lithium-ion battery, some LED lights, a refrigerator and a satellite dish can bring “civilization” to an entire rural village that has never had electricity before and otherwise never would.

    There is, in fact, a revolution in solar-powered off-grid rural electrification now getting underway — in Africa and India, for example. I think that’s more important to the future of humanity than worrying about how to maintain the fossil-fueled “materially rich” lifestyle that we in the West have become accustomed to (e.g. in the USA where more than 60 percent of our primary energy consumption is outright wasted).

    I would add that a “radically interdependent” civilization is, in my view, over-rated, and arguably part of the problem. An interconnected civilization, e.g. with universal access to communications and the exchange of information, is great. But a civilization that depends on moving huge amounts of material resources all over the place makes no sense, is not sustainable, and has no intrinsic value that I can see. I hope and expect that any civilization that manages to survive the effects of AGW that are sure to occur this century, will be based on local (bioregional) self-reliance, where human communities will learn how to live within the carrying capacity of the ecosystems of which they are a part.

  42. 292
    SecularAnimist says:

    Ric Merritt — I would respectfully suggest that The Oil Drum is not an especially great resource for keeping informed about what is happening now with the wind and solar industries — both the ongoing, accelerating deployment of today’s powerful and mature technologies, and the new technologies (especially in photovoltaics) that are at various stages of development from laboratory research to commercialization.

    Nothing against The Oil Drum — it is a great resource for monitoring developments in the oil industry, which is certainly important and valuable. But it is not really a site that is focused on renewable energy technologies. And my sense is that because of its focus on oil, and on the problems likely to be associated with (poorly handled) peak and decline of oil extraction, that it tends to be rather gloomy about the overall energy picture.

    There are quite a lot of sites now that cover developments in the wind and solar industries — the trade associations, various manufacturers and vendors, business-oriented sites, science-and-technology oriented sites, etc. I would urge you to seek them out. You may be surprised to find that there is much more going on than you realize, and much more reason to be optimistic about the potential of renewable energy than you think.

  43. 293
    J Bowers says:

    Any chance of a post some time on this research? Perhaps once the paper’s in print.

    Stanford climate scientists forecast permanently hotter summers beginning in 20 years

    The tropics and much of the Northern Hemisphere are likely to experience an irreversible rise in summer temperatures within the next 20 to 60 years if atmospheric greenhouse gas concentrations continue to increase, according to a new climate study by Stanford University scientists. The results will be published later this month in the journal Climatic Change Letters.
    […]
    “According to our projections, large areas of the globe are likely to warm up so quickly that, by the middle of this century, even the coolest summers will be hotter than the hottest summers of the past 50 years,” said the study’s lead author, Noah Diffenbaugh
    […]
    Diffenbaugh was surprised to see how quickly the new, potentially destructive heat regimes are likely to emerge, given that the study was based on a relatively moderate forecast of greenhouse gas emissions in the 21st century.

    “The fact that we’re already seeing these changes in historical weather observations, and that they match climate model simulations so closely, increases our confidence that our projections of permanent escalations in seasonal temperatures within the next few decades are well founded,” Diffenbaugh said.

  44. 294
    Nick Stokes says:

    Curiosities of our times. Rupert Murdoch’s mother, who is 102 and a grand dame of our town, has just signed an open letter supporting a carbon price.

  45. 295
    Chris Colose says:

    For those few here talking about Venus I just published my SkS piece

  46. 296
    Pete Dunkelberg says:

    While on the subject of xy&z check out this bit of serendipity. It has software engineering, kids and everything.

  47. 297
    Patrick 027 says:

    Re 280 Michele – part II – It is also interesting to consider the effect of just lopping off part of the atmosphere and shifting the surface upward. Will the temperature profile of the remaining part be the same? No, unless the removed air was sufficiently opaque at all relevant LW wavelengths. All of the net downward solar flux must still be balanced by convection + net upward LW flux at that point, which is now the surface; keeping it at the same temperature will tend to reduce the net upward LW flux at that point, because it is analogous to giving the lost portion of the atmosphere near-infinite optical thickness over a small distance. So the surface will tend to get warmer to boost the net upward LW flux. However, convection could also respond – but if the temperature remained the same, … (out of time, may get back to later).

  48. 298
    Patrick 027 says:

    … I meant the level where the surface has been moved to would tend to get warmer; the surface would get cooler, and anyway, that’s only considering radiation so far.

  49. 299
    Edward Greisch says:

    Your help is needed at:
    http://dotearth.blogs.nytimes.com/2011/06/14/an-effort-to-clarify-the-climate-conversation/#preview

    I am having trouble with the RC search engine. It gives too many results. I finally found the “Global Cooling Mole” after remembering the complete title. I still haven’t found the article you did about 97% of working climatologists agreeing on GW. I found maybe the wrong one or not the best one on scientists not getting rich on research grants.

  50. 300
    Uli says:

    Hi Chris Dudley (#109),

    I have reimplemented your program in octave and I think the calculation is basicly correct.

    But I does not understand your conclusion. Either you get other values that my program does or you may misinterpret the result. I does not think that the claim that the emission must fall to near zero is incorrect, but I think you, Chris Dudley and Ray Pierrehumbert, have a very different meaning of ‘near zero’ and the time scale.

    I think additional problems comes from the unrealistic choice of 1.5 in the line
    e(i+1:999)=e(i)/1.5
    This would mean an emission reduction of 33% per year, which would economical very unwise!
    I would suggest e(i)/1.02 instead, as in the increase.

    After extending the time you calculate the emissions from 499 to 999 (*) years you could check which concentration you get in the last year 2849, if the emission does never fall below and remain constant after the decrease at a prescribed level. Try for example 100%, 50%, 20%, 10%, 5% of the year 2000 emissions. Which values you get? For which value the concentration in 2849 is less or equal 450? What is in the case of 50%? It is sufficient to reduce the emission only to 50% of the value in 2000 to stabilize at 450ppm?

    Also I would suggest to see stabilization at 450 not as exactly 450, but als hold the concentration between 430 and 470 or so and only the approx 100year average is 450.

    (*) The formula of Kharecha nd Hansen is a fit for 1000 years.