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Unforced variations: Oct 2012

Filed under: — group @ 1 October 2012

This month’s open thread. Try to keep it at least vaguely focused on climate science…!


782 Responses to “Unforced variations: Oct 2012”

  1. 701
    prokaryotes says:

    EGU 2012: The latest dirt on reducing carbon emissions
    Scientists gather to discuss permafrost ecosystem recovery and the use of charcoal for counteracting carbon loss from soil.

    Permafrost and a neutral emissions cycle
    Above latitude 50˚ north, permafrost soil—that is, soil that remains below the freezing point of water—holds about twice as much carbon as does the atmosphere. As temperatures increase, permafrost degrades and could release at least 10% of its trapped carbon into the atmosphere, according to Ko van Huissteden of Amsterdam’s Vrije University.
    Re-vegetation can actually recover greenhouse gas sinks, as new populations of CO2-hungry plants get busy photosynthesizing. But van Huissteden referred to recolonization of plants in thawed areas and the ensuing recovery of the ecosystem as a “neglected factor in carbon release by permafrost degradation.”
    The number of ponds from melted permafrost has tripled in 30 years, and they have submerged and killed vegetation, said van Huissteden. But at the same time, sedges, a family of flowering plants that resemble grass or rushes, are recolonizing the ponds. The plants emit methane (CH4) but take up CO2, which has resulted in carbon-neutral emissions. Another possible recolonist is peat moss. If it becomes widely established, it could lead to an exponential decrease in greenhouse gas emission rates.
    The East Siberian Arctic Shelf provides another example of permafrost effects. Supposedly impermeable subsea permafrost traps coal bed methane. But recent data suggest that the permafrost is thawing: No frozen sediments were found in a 53-meter-long drill core from 2011. In a talk at EGU, Natalia Shakhova of the University of Alaska Fairbanks said that the destabilized subsea permafrost is currently leaking a “substantial amount” of methane, which is becoming involved in the modern carbon cycle. That aqueous CH4 may avoid biological oxidation in the relatively shallow water and escape to the atmosphere.
    Permafrost degradation is a transient greenhouse gas source whose evolution over time is important. Climate models should include its degradation and ecosystem recovery to predict carbon feedback with more certainty.
    Biochar and a negative emissions cycle
    Non-permafrost soil also contains carbon that can escape into the atmosphere, especially when treated with fertilizers. Jorge Paz-Ferreiro from the Polytechnic University of Madrid looks to applying charred organic matter, or biochar, to the soil as a way of storing carbon and reducing the need for fertilizers.

    Biochar is made by pyrolysis. Biomass (often agricultural waste) is heated to high temperatures and the oxygen supply closed off so that the biomass’s carbon content cannot combust and is instead safely stored as charcoal. Added to soil, biochar can remain for centuries with potentially positive benefits for plant life, including increased growth and disease resistance, thus reducing the need for standard greenhouse gas–intensive fertilizers.
    Microorganisms break down a soil’s organic material, which releases mainly CO2 but also some methane. Biochar’s low ratio of both oxygen and hydrogen to carbon gives it a graphite-like structure, which is decomposed by microorganisms much more slowly than other organic matter: It’s like moving from a quick carbon cycle to a slower carbon cycle.

    “Biochar itself carries no nutrients,” explains Paz-Ferreiro. Rather, it would be used to complement traditional fertilizers and could reduce the fertilizer requirements of a crop as it “retains some of the nutrients in the fertilizer.” Although biochar generally increases crop yields.

    Storing atmospheric CO2 in deep geological formations may be the high-profile way of cleaning up greenhouse gas emissions. But understanding and optimizing the role of soils in the carbon cycle provides important mitigation possibilities as well. http://www.physicstoday.org/daily_edition/down_to_earth/egu_2012_the_latest_dirt_on_reducing_carbon_emissions

    I think we also should assess if we can dumb Biochar on thaw’ed permafrost and thermokast to minimize greenhouse gases.

  2. 702
    flxible says:

    prokaryotes – Biochar is best categorized simply as an adjunct to sustainable organic agriculture, like proper composting, it improves all aspects of soil productivity: tilth, fertility and vital nutrient sequestration. Biochar benefits the carbon cycle, but that’s not the primary reason for its use. Geoengineering is a deliberate intervention in the climate system for the sake of creating changes we don’t yet fully understand the effects of.

  3. 703
    prokaryotes says:

    Climatologist should prepare handy information sheets for the mass media in light of another 500 year event.

    Where should i go to get the latest science in connection to this unprecedented storm on the east coast?

  4. 704
    Hank Roberts says:

    One more, then I’ll shut up for a while, I hope.
    This one’s a dissertation, don’t know if it went on to further review
    https://circle.ubc.ca/handle/2429/42101

    Effects of harvest and climate change on polar marine ecosystems: case studies from the Antarctic Peninsula and Hudson Bay
    C Hoover – 2012 – circle.ubc.ca
    … Future simulations of the Antarctic Peninsula identify large reductions in ecosystem biomass of all species due changes in environmental conditions and an overall reduction in krill, with minimal ecosystem impacts from harvest. …

    Hm.

  5. 705
    Patrick 027 says:

    … weather comment, with related climate question followup tomorrow…

    Sandy is really interesting. I was hoping that the track would go farther inland to the Great Lakes though – I wanted to see a subtropical lake-effect blizzard…

  6. 706

    I’ve worked out a theory for the High Pressure block diverting Hurricane Sandy, and there is some good evidence that the Arctic Ocean open water is in good part responsible for it. Read more: http://eh2r.blogspot.ca/

  7. 707
    Stranger says:

    Over the years I’ve lurked here I remember more than one occasion where the skeptics misrepresented published studies. This is a little different. Here in Bloomington, Indiana congressman Todd Young claimed during an exchange with the Monroe County Religious leaders that Indiana University’s Dr. Simon C. Brassell, IU Professor of Geological Sciences believes there is no AGW which supports Young’s claim that there’s no AGW. Dr. Brasswell’s name appeared on a list of contrarian researchers by Senator James Inhofe. In a Letter to the Editor in this morning Herald Times Dr. Brasswell is quoted, “The presence of my name on the list, both then and now, is perhaps symptomatic of the falsehoods perpetuated by those who deny human-induced climate change. However, until receiving your message I was unaware that anyone, including local politicians, would cite my name in support of a position of skepticism.”
    http://www.heraldtimesonline.com/stories/2012/10/28/lte.288406.sto

    What I’d love to see put together is a list of the misrepresentations made by the deniers. Does anyone know if there’s such a list? It seems like it would be helpful.

  8. 708
    SecularAnimist says:

    Jim Larsen wrote: “HVAC thermostats available to the average guy control temp in full degrees. GE can do at least an order of magnitude better.”

    With all due respect, repetition of baseless, unsupported, vague assertions very quickly becomes boring.

    What specific geoengineering scheme(s) are you referring to?

    Where is the experimental evidence that demonstrates what those specific schemes “can” do?

    Specious analogies between the Earth’s climate system & biosphere, and simple on/off electromechanical devices, do not constitute such evidence.

    Jim Larsen wrote: “Your skeleton starts dissolving and you refuse to change the thermostat even though the doctor says your skeleton is heat-sensitive.”

    I’m pretty sure that Hank was referring to ocean acidification, not temperature.

  9. 709
  10. 710
    Jim Larsen says:

    700 Ray L said, “In contrast, we have a pretty damned good idea how CO2 works. It would seem to me that we might want to try that first.”

    Agreed. Similarly, we should probably use our car’s brakes instead of relying on the seat belt. Thus, we should not install seat belts in cars?

  11. 711
    Jim Larsen says:

    708 SecularA said, “With all due respect, repetition of baseless, unsupported, vague assertions very quickly becomes boring.”

    Agreed, which is why I’ve repeatedly asked you to substantiate your 15ppm claim. Fortunately, I always substantiate my comments, and if I miss something, I always respond, such as when Hank asked me to cite up-thread. I asked him ‘cite what?’. He never clarified, so I assume it was minor. Now I’m asking you to cite.

    “I’m pretty sure that Hank was referring to ocean acidification, not temperature.”

    I’m pretty sure the analogy was open to interpretation. I visualized arctic sea ice, as that is affected by “the thermostat”, while ocean acidification is not. I was clear that my comments are about non-carbon GE schemes, such as sulphur injection. Ocean-acidification mitigation schemes seem far-fetched to me, so I wasn’t considering them. Maybe we’ll “have” to go there too.

    So, to help move this in a productive fashion:

    1. Substantiate your 15ppm claim.

    2. Estimate the odds that we’ll meet your goal (15 years to 0) (15ppm)

    3. Given your answers above, what are the odds that without GE we’ll bake?

    4. Now conclude by telling us why studying GE is bad. (And remember “studying” does not equal “deploying”)

  12. 712
    Jim Larsen says:

    Geese and ganders, so I’ll answer too, without cites but willing to engage in a discussion which substantiates:

    1. The horse has probably already left the barn. 15ppm is tiny compared to the 110ppm we’ve already spewed.

    2. 0%

    3. 100%

    4. Because it is a distraction to the core goal, and will change the answers to 2 and 3 to 0% and 100%. Oops, that’s no change!

  13. 713
    SecularAnimist says:

    Jim Larsen wrote: “which is why I’ve repeatedly asked you to substantiate your 15ppm claim”

    I don’t have the slightest idea what you are talking about. I have never made any “15ppm claim”. I don’t think I have ever posted any comment that mentioned 15 ppm or any other ppm in all the time that I’ve been posting comments on this blog. You must be confusing me with someone else.

    Jim Larsen wrote: “Now conclude by telling us why studying GE is bad.”

    Again, I have never said that “studying GE is bad”. What I have said is that your assertion that some unspecified geoengineering scheme or schemes “CAN” — and that was your word, “CAN”, not “conceivably might” or “possibly could”, but “CAN” — control the Earth’s temperature as accurately and reliably as a simple elecromechanical on/off thermostat controls a furnace, has no evidence whatsoever to back it up.

    If there’s anything more boring than repetitive baseless assertions, it is comments that claim I’ve said things that I have never said.

    Now if you’ll excuse me, I have to prepare for the imminent arrival of an AGW-driven Frankenstorm.

  14. 714
    Patrick 027 says:

    … “AGW-driven Frankenstorm” …

    Well, aside from what the extra H2O vapor (locally via a warmer ocean in this case?) in the atmosphere would add, it’s not obvious to me that this is the case, although I can imagine circulatory changes could contribute.

    But I had been wondering for a while:

    Why can’t the average tropical cyclone tap into the energy of a (baroclinic, hence associated with wind shear) jet stream, rather than being weakenned by it? Did Sandy manage this feat due to it’s spatial extent – did it more closely match an unstable wavelength for baroclinic development? Or is the issue that (from “PV-thinking” (that’s a phrase I actually read somewhere) baroclinic instability requires a reversal of PV gradient somewhere over the vertical direction, and typically this is between the atmosphere in general and the surface (potential) temperature gradient – whereas the subtropical jet is associated with a temperature gradient aloft (that itself would require a stability gradient that would tend to provide the necessary PV gradient but this may be overwhelmed by beta-effect, etc.)…

    On the other hand, latent heating can and does contribute to the average extratropical cyclone, right? Could this at some point lead to embedded ‘tropical cyclone’ development within the core of such a system even outside the tropics and perhaps even removed from the ocean if a sufficient stream of moisture is flowing in the atmosphere?

  15. 715
    Jim Larsen says:

    SecularA said, “I don’t have the slightest idea what you are talking about. I have never made any “15ppm claim”.”

    Oh, so you DIDN’T say we have 5 years to start and 10 additional years to complete a drawdown to essentially zero emissions? Golly, that’s rich. Or, are you just spouting nonsense and avoiding the math which inevitably results?

    “control the Earth’s temperature as accurately and reliably as a simple elecromechanical on/off thermostat controls a furnace,”

    Obviously you’ve never investigated the tremendous inaccuracy of HVAC controls – they are designed to swing through a fairly large range. Otherwise, your furnace would go on and off constantly. Or are you saying that GE can’t control the Earth’s temperature to perhaps 3F?

    And you didn’t bother answering the questions. Obviously, you’re much more comfortable spouting nonsensical claims and not even having the sense to understand that 15 years to 0 = ~15ppm, even when you’re spoon-fed the information.

    Though we’re getting somewhere. Now you agree with me that studying GE is a good thing? So you have no problems with anything I’ve posted? (I’ve still got huge misgivings about your 15 year/ppm claim)

  16. 716
    Jim Larsen says:

    SecularA,

    My guess is you’re backwards. You studied and decided that 10 years is the absolute minimum timeframe we could get off fossil fuels if you were World Dictator and enforced your desires via gunpoint. You then added 5 years for “getting with your Godly program”.

    NOTHING to do with science at all. 15 ppm in a logarithmic system already at 392ppm is rounding error, consequence-wise.

    That you refuse to substantiate any of your wild nonsensical claims pretty much proves my point.

    Answer the 4 questions.

  17. 717
  18. 718
    Ray Ladbury says:

    Jim, you are asking the wrong man about seatbelts. I have long joked that rather than airbags, they should install a 6-inch spike on the steering column to make people think twice about tailgating or driving too fast. It is my contention that driving would likely improve vastly in short order.

  19. 719
    Hank Roberts says:

    Hank was referring to ocean acidification.
    Surprising you think that’s open to interpretation, if you’d googled it you’d know why it’s a major problem.

    I’d like you to cite your assertions.
    Likely others would also.

    (Unless you’re a published author; if so you can rely on people looking up your journal papers to check what you say; the names in the sidebar are like that)

    It’s a way to build credibility.

  20. 720
    Susan Anderson says:

    Found this item about Mike Mann. No doubt it’s not news to other readers here, but nonetheless:

    http://www.mcclatchydc.com/2012/10/23/172371/penn-state-climate-scientist-files.html

    Penn State climate scientist files defamation suit
    By Renee Schoof | McClatchy Newspapers
    Penn State University scientist Michael Mann, whose work showed that Earth’s temperatures have risen along with increased fossil fuel use, announced Tuesday he had filed a lawsuit against the conservative National Review and the Competitive Enterprise Institute for defamation, complaining that they falsely accused him of academic fraud and compared him to convicted child molester Jerry Sandusky.

    Organizations that deny climate change is a serious problem have condemned Mann for years.

    Mann was one of the scientists whose emails were hacked from a climate research center at Britain’s University of East Anglia in 2009. Climate skeptics quoted portions of the emails in an attempt to discredit the scientists in what the critics dubbed “Climategate.” But government and university investigations found no misconduct.

    The lawsuit, filed Monday in the Superior Court of the District of Columbia, argued that the two conservative outlets and two writers named in the suit, Rand Simberg and Mark Steyn, “maliciously accused (Mann) of academic fraud, the most fundamental defamation that can be levied against a scientist and a professor.”
    ….

  21. 721
    Jim Larsen says:

    718 Ray L said, ” they should install a 6-inch spike on the steering column”

    LOLOL. Yes, you are truly grand. I think I asked precisely the right dude. :-)

    719 Hank R,

    Analogies are useful precisely because they are imprecise. Thus, they open the mind. Writers often are surprised at how study groups interpret their words. I made no contentions about ocean acidification other than that GE ain’t gonna help unless some far out plan actually works (such as digging up Australia and dumping it in the ocean). My personal belief is that ocean acidification is the concrete wall we’re accellerating towards. Are you saying that stance is wrong or needs cites?

  22. 722
    Jim Larsen says:

    OK Hank:

    Log 392 = 2.59
    Log 407 = 2.61

    The difference is negligible. (Now, I think the calculator used base 10 and perhaps e is proper, but the result should be robust. TIA for corrections)

    Anything else need citing? Since I’m slow, I’d like a list. I promise to fulfill your every citation desire.

  23. 723
    Jim Larsen says:

    Hank,
    In my opinion, the asking for a cite should be accompanied by a cite showing your position. 99 times out of 100 I accept other folks’ cites. basically, you’re refusing to say what it is you disagree with, and refusing to provide any anything about the alleged subject, and demanding I guess what it is you are talking about, and answer it in whole cloth. Right?

    Myself, I think that blogs are about gathering various talents and coming up with ideas and answers. No single individual is key. You disagree with something I say? Don’t be shy. Give the Truth as you see it. I’ll either accept it or dig for something deeper. Our goal is to come up with something new together.

    This reminds me of the old complaint about deniers. They demand that every comment be made from first principles. Obviously, that means no comments are allowed. Are you like deniers?

  24. 724
    Didactylos says:

    #720

    See, it’s cases like this, when big media steamrollers all over the reputation of a scientist, that the UK libel system is designed for. The US system leans so heavily in the direction of free speech that Mann will have an up-hill battle. I wish him all the best, and will be watching closely.

  25. 725
    SecularAnimist says:

    Jim Larsen wrote: “Answer the 4 questions.”

    Your “4 questions” are nonsense. Your comments to me are nonsense — not to mention deliberately offensive and belligerent, in other words “flame bait”, in other words, the work of a troll.

    I have not made any “15ppm claim”. That’s something that YOU came up with using guesswork and ill-informed assumptions and back-of-the-envelope scribbling and “axioms” that you pull out of thin air, and now you want to pretend it was “my claim” and demand that I back it up. It’s just silly.

    If you look at my original comments regarding stopping the increase in GHG emissions within five years, to be followed by steep reductions to near zero emissions within ten years, you will see that I have in fact cited, and quoted, sources — beginning with the IEA’s recent report.

    Of course you won’t do that because you NEVER read any link that I post here.

    Just as you prefer to post “axioms” about the economics of deploying photovoltaics today while ignoring actual economic facts that have led numerous major corporations to invest heavily in large-scale PV deployments, you prefer to ignore what I actually write here, and instead just make stuff up, pretend that I said it, and make bullying demands that I substantiate YOUR nonsense with citations.

    It’s a silly game, and it was tiresome 20 years ago when people first started playing it on USENET.

  26. 726
    Hank Roberts says:

    For Jim Larsen, this should be helpful, it’s information you can be providing (with understanding) to assert your position.

    Point is when you make a broad-brush assertion, showing you’ve done some reading and can help readers understand your thinking can add to your credibility. Don’t assume this is the only or best support for your GE statements (that would be ‘reverse citation’ — a deplorable practice of making a claim then posting anything that can be googled and calling it a cite).

    Point is — show some evidence you know the literature and your claims are more credible as people will look at your sources and weigh them.

    We have a few commenters here whose ‘cites’ are perfect negative indicators, they’re consistently misrepresenting the science; most of the regular readers have made the effort to look at the science before making claims.

    This paper below is an outlier, not a consensus opinion, as I read it, but from a good lab with a strong reputation for good work; you should make up your own mind, referring to what’s available.
    http://dge.stanford.edu/labs/caldeiralab/Caldeira_research/Matthews_Cao.html

  27. 727
    Hank Roberts says:

    PS for Jim, “cite” means “citation” — I assume you’re being funny, giving people answers that are just arithmetic. You’re assuming everyone reading can follow you. It makes you appear like you’re showing how smart you are.

    But most won’t or can’t follow such terse replies. This need not be a debate nor a win/lose writing game.

    I’m asking you to try a bit harder to help your readers == including those who come along later — understand the science by being able to look up sources, rather than by trusting you.

  28. 728
    Chris Korda says:

    Jim Larsen: Could you possibly manage to dial back the belligerence? It makes for tiresome reading, and our hosts have on multiple occasions expressed the view that it’s unwelcome here. Just make your case calmly and let your readers decide if it’s persuasive.

  29. 729
    prokaryotes says:

    An interesting perspective on personal bias. Especially in light of what psychologist call the social dissonance.
    Critical Thinking – Must Watch #climate #debate #psychology #social #dissonace
    http://www.youtube.com/watch?v=6OLPL5p0fMg&list=PLE8B1470B8A846BB1&feature=player_embedded
    Reply

  30. 730
    Jim Larsen says:

    [edit – no attacks on other commenters (and no ripostes in kind either)]

  31. 731
  32. 732
    Patrick 027 says:

    re my 615,629,632,635, and 679:

    The C(j) in m, and C(j-1,j) and C(j,0) in m/yr:

    j, C(j), C(j-1,j), C(j,0):

    1, 50, 20 , 8
    2, 50, 12 , 6
    3, 100, 6 , 3.35
    4, 300, 2.65, 1
    5, 400, 1.65, .33
    6, 400, 1.32, .33
    7, 400, .99, .33
    8, 400, .66, .33
    9, 500, .33, .33

    The first column is an index number; the second is heat capacity of each reservoir in m H2O equivalent. The third column is the heat capacity (m H2O) per year transported to that reservoir from the reservoir above, and the fourth is that transported from that reservoir to the surface reservoir (j=0). Notice that C(j,0) = C(j-1,j) – C(j,j+1).

    Note that the flow from C(3) to C(4) is 1/1000 of the whole ocean per year. If these layers were stacked vertically, this would correspond to 1/1000 of the ocean per year flowind downward across a depth in the ocean of roughly 360 m. I’m not sure how realistic that is.

    I used a time_step of half a year.

    For constant forcing of 1.233 W/m2 and all T(j) = 0 at 0 years:

    T(0) (surface temperature anomaly) nearly follows the exponential decay toward equilibrium based on C(0) only (based on time_constant = ECS * C(0)) for the first year, then lags behind. The T(0) response intersects exponential decay based on C(0)+C(1) between 4 and 5 years, exponential decay based on C(0) through C(2) just after 10 years, and c(0) through C(3) around 27 years (graphically estimated time values). When graphed over the logarithm of time (where the exponential decay to equilibrium looks like an S curve), T(0)’s approach to equilibrium may be approximated by two linear segments (after year 0.5 or 1), the first going to about 76 % of equilibrium response around year 70, and the second getting to near 99 % sometime around 4000 years (graphically estimated). The response lags behind the exponential decay for when all the heat capacities are immediately accessible to the surface after somewhere between 600 and 700 years. This makes sense given that the more rapid initial response for finite flow through the depth of the ocean reduces the radiative disequilibrium (the heat source) faster, so that it then takes longer to heat up the rest of the system (the weighted-average T of the system nearly follows the exponential decay for that amount of heat capacity for ~ 2 years and then lags behind).

    I tried a convex-curved triangular forcing pulse (peak in 50 years, back to 0 in 100 years) and the surface temperature peaked after forcing peaked but before intersecting Teq. Some deep ocean reservoirs peaked after that point. Notably and, what one should expect, the heat capacity-weighted average T peaked within about 1 time step of when Teq intersected surface T; and the argument I gave earlier about peaking at the intersection should tend to apply (at least with some simplifying assumptions) to that average T (although that average T is not intersecting Teq).

  33. 733
    Patrick 027 says:

    The last comment was supposed to begin with:

    The surface heat capacity C(j=0) was set to the equivalent of a global layer of water 50 m deep (which would be a layer ~70 m thick over the oceans) plus 70 % of the atmosphere, the latent heat of vaporization corresponding to a 20 % increase in water vapor per 3 K warming (linearized for current conditions), and a little land surface; expressed as W*yr per m^2*K (a convenient unit), I got about 7.093.

    A global 50 m layer of water has about 6.683 W*yr per m^2*K

    I set the rest of the heat capacities and heat capacity exchange rates (per year) as exact values in terms of global m water.

  34. 734
    Patrick 027 says:

    … not intended to suggest that the heat capacity exchange/transfer/transport rates used are a realistic representation of actual ocean circulation, although from what little I know, it could be a step in that general direction from using one upper and one deep ocean reservoir.

  35. 735
    Patrick 027 says:

    About Sandy –

    Wind speed is a useful measure of storm strength (cat 1-5, (E)F scale…), and pressure drop also (~ wind speed * distance scale ~ speed*sqrt(area) if not too elongated) – although (I think) potential energy ~ area*(change in p^2) and kinetic energy ~ area*speed^2 (assumes same vertical extent, density…)

    How about storm mass? The mass of air that had to be removed from the area of the storm to result in that (surface) pressure? Would that be an interesting metric?

  36. 736
    Patrick 027 says:

    … ~ 1000 km ^2 * pi * ~ 50 mb * 1/3 (assumes conical shape) …

    Sandy’s mass roughly 5*10^14 kg (very rough estimate. radius may be off; didn’t see where the 1000 mb isobar was).

  37. 737
    Jim Larsen says:

    727 Hank said, ” I assume you’re being funny, giving people answers that are just arithmetic.”

    and 728 Chris K said, “Could you possibly manage to dial back the belligerence?”

    No problem. It was frustration, not funniness. I want to comply with requests for cites, but since I have no clue what part of which comment folks have a problem with, I can’t. I made a wild guess, and apparently got it wrong. I thought my four questions were clear, pertinent, and spot on in every way. Again, I got frustrated by the stonewalling. Chris, you’re way right that I shouldn’t let such things bother me, and I apologise for detracting from the RC experience.

  38. 738
    Chris Dudley says:

    Patrick (#732),

    Such ocean models have been coupled with climate models already. We’ve just been trying to take those results and apply them to forcing profiles that have not been run in the models. The lag time scales are already calculated for a response to an instantaneous 4 W/m^2 step up in forcing. The question is how to use that given that the Green’s function approach has some unphysical side effects. I’ve developed some analytic functions in both the actual temperature and target temperature that are showing some promise. But they need more work.

  39. 739

    #737–I appreciate that, Jim L. You have interesting and provocative ideas; but FWIW, I think I’d second Chris K’s suggestion for making them shine forth a bit more clearly.

  40. 740

    I’ve read Mike quoted in one article about Hurricane Sandy:

    “We can’t blame the existence of a single hurricane on global warming, just like a die weighted to roll sixes can’t be blamed for any single roll of a six,” said Michael Mann, a physicist and the director of the Earth System Science Center at Pennsylvania State University. Sixes, after all, will sometimes happen anyway, even when the dice aren’t loaded, Mann explained.

    “But we can see that climate change is playing a role in setting the context for these storms,” Mann continued, “in particular the record levels of North Atlantic ocean warmth that is available to feed these storms with energy and moisture.”

    Superb statements but there is more to this event than just a Hurricane, the general atmospheric circulation was set to divert it towards New Jersey, instead towards the usual cooler NE Atlantic. It is more complex than simply warmer sea water, but easier to understand if explained in greater details. RC should consider an essay. The noble reluctance to release expert knowledge quickly in favor of a peer reviewed paper removes the focus gained at this time when almost every climate scientist is observing this event with great attention. In addition, the greater discussion gained by the huge talent of commenters here would be invaluable to all.

  41. 741
    Jim Larsen says:

    I agree with SecularA that it’s probably too late to prevent a massive crash without GE*. With GE, well, I have no idea what anybody here thinks, other than that it won’t save us from OA (except maybe wild and huge schemes) and that GE is just plain wrong on an emotional level.

    I see GE as a short term band-aid to be used to prevent the demise of arctic sea ice and permafrost while the oceans et al absorb some of our excess CO2.

    My guess is that folks see the horrific vision of permanent GE allowing continued carbon pollution and just shut down their logic circuits. Or perhaps folks think that if we let the GEnie out of the bottle, we’ll go straight to the horrific vision, so it is better to just stab ourselves in the chest with Ray’s 6″ spike.

    *He said a 15 year drawdown is possible, and that would only give us “any hope”.

  42. 742
    Patrick 027 says:

    re 738 Chris Dudley – certainly it has been done already with far greater sophistication including variable circulation, etc.; I just wanted to see what kind of behavior I’d get, and we’ve now got an explanation for why surface temperature could start declining even when Teq (instantaneous response) is still higher.

    If one assumes the circulation patterns don’t change in such a way as to affect this (and some other things) – I’m not sure what form the response function was in; I’ll have to go back and look at the comments above – but if it was given as a function over time f(t) as a fraction of the equilibrium response f(t) = T(t)/Teq for a constant forcing switched on at t=0, then (given various simplifying assumptions) one could use linear superposition –

    Where radiative forcing = RF(t), each step in RF (here written as a differential), d(RF) for each step in t, dt, @ time t = tn, would contribute a climate response dT(t-tn) = f(t-tn)*ECS*d(RF)(n) … I could have tried to write that more clearly but does this make sense?

  43. 743
    Chris Korda says:

    Patrick @741:

    I’m not sure what form the response function was in;

    Hansen’s climate response function as originally formulated is a pain to use because it’s defined in log space, but once it’s been interpolated it’s just an array of 2000 descending percentages which model how a given annual forcing would be distributed over the next two millennia. Here’s the interpolated data in case you want to add it to your spreadsheet. But what I’m not clear on is, are you proposing to replace Hansen’s climate response function, or change how it’s applied to projected forcing data?

    dT(t-tn) = f(t-tn)*ECS*d(RF)(n)

    ECS is Equilibrium Climate Sensitivity in K/(W/m^2) right? In other words it’s a constant for our purposes. But where is the function f defined in all this? Is it in one of your previous posts?

    There’s another possible problem that I was going to mention earlier. If you look closely at the plots linked to #650, you’ll notice that of the three climate response functions Hansen described (slow, intermediate, fast), only “slow” gives a reasonable value for 2012, i.e. ~0.8ºC above pre-industrial. Intermediate gives ~1ºC and fast gives ~1.15ºC, both too high no? But the whole point of Hansen’s paper is that while “slow” allegedly approximates current climate models, “intermediate” is more likely. In figure 7 of the paper, he shows a blizzard of graphs, in which he uses an additional variable (aerosol forcing) to “tune” each of his three climate response functions to the historical data. Or perhaps I’m misunderstanding this part? But if not, it’s unclear what predictive value the “untuned” climate response function would have, if any.

  44. 744
    Chris Dudley says:

    Patrick (#471),

    The climate response function derived from a coupled model run responding to a doubling of carbon dioxide is monotonic so I don’t think we are looking for circulation explanation. I think it is a problem with just the sort of linear treatment that you are proposing which accounts for the change in the forcing, but not the response of the system except as portrayed in the step function response.

  45. 745
    Nick Gotts says:

    “If you can come up with a significant number of people here who think studying STDs is wrong, then your point will be valid.” – Jim Larsen

    It’s valid anyway, since nobody has said anything like the belief you attributed to “”everybody””, and since the concern that researching geoengineering will provide another excuse not to cut emissions is valid, and you have given no reason to think otherwise.

  46. 746

    since the concern that researching geoengineering will provide another excuse not to cut emissions is valid, and you have given no reason to think otherwise.

    I don’t know about him, but I do. You (as in we) are already committed to geoengineering since emissions will not be cut enough to undo the damage that is already done and in the pipeline. I have already pointed out that the most reasonable approach to this situation is solar lagrange point L1 occultation, since that solves a myriad of other severe cultural problems in science and technology while giving us the time to work out drawdown stuff.

  47. 747
    Jim Larsen says:

    744 Nick G said, “It’s valid anyway, since nobody has said anything like the belief you attributed to “”everybody””, and since the concern that researching geoengineering will provide another excuse not to cut emissions is valid, and you have given no reason to think otherwise.”

    I believe you just did. Excuses are emotional. :-) There are plenty of folks who fought against the HIV fight for a similar reason – it would only encourage gays to “sin”.

    Pretty much anything that can be will be used by some as an excuse to not cut emissions. Perhaps studying GE will make “the” difference, but I doubt it, especially since studying GE is essentially in the future and IMO “emitting too much CO2″ is already done, especially when locked in future emissions are counted. Nobody’s going to shut down their brand new power plant for many decades.

    OTOH, studying GE will scare the bejesus out of many folks, giving them incredible incentive to cut emissions. Which will be the larger factor?

    Are you saying that that we won’t lose the sea ice without GE (in a reasonably probable scenario)? Are you saying losing the ice and thawing the permafrost is no big deal, or at least less of a deal than giving some folks an excuse? Are you avoiding the inevitable linkage?

  48. 748
    Steve Fish says:

    Re- Comment by Jim Larsen — 29 Oct 2012 @ 9:07 PM:

    You say “I want to comply with requests for cites, but since I have no clue what part of which comment folks have a problem with, I can’t.”

    Because you also say- “I always substantiate my comments.” Why don’t you start with your assertion that climate can be adjusted just like a household thermostat with geoengineering. This has been questioned repeatedly without you providing any support whatsoever. Just claiming that others don’t understand the effect of sulfate dimming from volcanoes is not support. I have not heard of any control knobs on volcanoes.

    Please provide links to scholarly works examining whether it is possible and practical to geoengineer global dimming. This should include cost estimates and the problems due to dumping more pollution into the commons. Op-eds and opinion pieces, and the eructations of the like of Bjorn Lomborg or Levitt and Dubner are not scholarly.

    Having made such a sweeping statement you must have already read these kinds of sources and can produce them readily. If you haven’t checked this area out already then shame on you. I found 192 scientific articles in about 10 seconds. Have at it. Steve

  49. 749
    Chris Dudley says:

    Chris (#743),

    Actually, the log scale makes the plots easier to use, not harder. Imagine trying the figure out the response in the first couple of years from a linear plot.

  50. 750
    Patrick 027 says:

    Re 743 Chris Korda – I didn’t look through your code entirely before.

    I was primarily concerned with the issue of T peaking before intersecting Teq (instantaneous), and I no longer ‘have a problem’ with that.

    Is that array (Hansen’s response function) of percentages meant to indicate the percentage of the equilibrium response since a step-wise change in forcing? If so than that’s what I meant by f(t).

    For radiative forcing RF(t) = { RFn for t ≥ tn , 0 for tn > t }
    Teq = ECS*RF
    Teq(t) = { ECS*RFn = Teqn for t ≥ tn , 0 for tn > t }

    Let f(t-tn) = { T/Teqn for t ≥ tn , 0 for tn > t }

    Then T = f(t-tn)*ECS*RF(t) for a single step in forcing at t=tn.

    Any RF(t) is the integral of d(RF)/dt, and T(t) could be given by the integral over tn of f(t-tn)*ECS*d(RF(tn))/dt * dt, where I mean d(RF(tn))/dt to be the rate of change in RF at t=tn.

    Or numerically sum over an approximating series of finite RF steps.

    Is that what you did?


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