Not consciously as I never thought about it but certainly that must be true as it is without exception, I think , that whenever one "unbinds" a collection of bound atoms, some form of energy must be supplied - could be given by a passing cosmic ray's electric field impulse, and it is a stretch to call that endothermal, but it is. (Of course if the freed atoms re-combine in some more tightly bound system, then the net could be exothermic.) I was aware that a branch of the Gulf stream's denser water flowing along the Siberian coast line's bottom (as seems to be starting) deliveres the required thermal energy much more effectively than ice-free Arctic waves mixing surface water down (with help of gravity) does. I.e. the waves drive water toward the shore and it rises higher than an equal gravitational potential surface. - Just like in creation of El Nino, water rises up even 20 feet higher along Asian shores. BTW thanks for your list of links on methane burps, etc. I'll work my way thru them, I hope, when have time. I know of several too, but mostly from people in the Arctic Emergency Group (or others with that POV). I assume your list is less biased. Right now I am studding Brillvon's second link. It is aware of both your 1988 link and Hanson 2009 paper - one saying thermal run-a-way can't happen and the other that it is certain, if business as usual continues. This paper's model has Earth's atmosphere with oceans adding H2O and various loads of CO2, and leans to conclusion that thermal run-a-way is not possible until the sun get hotter, but admits that may be false in the last sentence of the conclusion. Earlier in the paper it admits that the conclusion may b false and lists some reasons - one being lowering of albedo down to 0.16 from current 0.32 via ice and snow melting, (or high clouds with more black particles in them, I'll add). Another is the model considered only CO2 & H2O, but another GHG, considered as well, which would block the escape of IR in couple of identified wave length band where water vapor is not a good absorber and also admits that even water has an absorption continuum when two molecules collide, (as they would in dense steam atmosphere) may let thermal run a way happen. That continuum absorption increases with the square of the density - but was ignored even though the density became huge as most of the oceans became vapor. I admit I am a little confused by their discussion of this as they also say they are using a grey radiator model for the IR. - Perhaps they mean that instead of the complex, computationally expensive, use of actual line structure in the stronger IR bands, they just assigned a less than unity but constant emissivity with the net IR as "reduced black body" - that dependency on temperature and ignored the continuum outside of the stronger absorption bands? I was well of the fact IR does not escape from the surface but from higher up (roughly from one "optical depth" deep in the atmosphere) but did not fully appreciate that this leads to a max IR escape limit and run-a-way is only possible if the rate of absorption is greater (or if the assumption made of a grey IR radiator is false - as it is in the wave lengths band he names for water.) One of the first things I will do is look at CH4's absorption bands. Also very interesting and new to me was that when one considers the atmospheric circulation, Hadley cells - see drawing at end, the equatorial region can be in "incomplete thermal-run-a way" with energy convected towards the poles, where it escapes to make a stable system, with that transport effectively raising the max IR loss rate possible. - I. e. Earth has several hotter stable states - not just current one and "Venus like" one. Probably even coolest of these hotter stable states make mammals extinct. I encourage you to read this recent paper which is much more in doubt on the question of thermal run-a-way. - It calls for more complete modeling effort before any conclusion is to believed as fact. PS I had trouble getting Brillvon's second link to open but via Google & title, found it here: http://arxiv.org/pdf/1201.1593v1.pdf It is from January 2012, by real experts very aware of prior work on the question. - I find it very hard to believe that any doubt free answer to the thermal run-a-way question exists.* - It is not that just iceaura has not looked at the literature enough - Currently thermal run-a-away is an open question, as these authors admit - too many not fully valid assumptions used and many things, including methane, and water vapor continuum absorption blocking IR's escape in those wave length regions, just ignored, in the analysis done. Interesting too is fact confidence in the "not possible" answer is so low that one section discusses: What will be the warnings? and another: What could we do, if warning are available - best answer they think is to move earth farther from the sun via interaction with an asteroid - much like man picks up "gravitational assist" by near misses of other planets (some times even 3 or 4) to get his spacecraft to the outer planets. Another interesting thing I learned, quoting: "the entire ocean will not boil: a liquid ocean remains until the critical point is reached at Tc = 647K." This is because as much of the ocean does evaporate the atmospheric pressure is greatly increased and boiling point at high pressure is too - finally there is no boiling point as the vapor and liquid are one and the same. * Again, this question is only of "academic interest" becuase man will never confirm the answer even if it is possible, as man will have been extinct long, very long, before it can be observed (unless man has colonized Mars, etc. except if transition occurs quickly (huge CH4 burp OR by the much more likely process I note is possible** after the Hadley cell diagram below. Please Register or Log in to view the hidden image! Note that where warm air is rising even this diagram shows high altitude clouds form. If the since 2005 drought in the Amazon continues, for a few years more, not only will the Amazon be a net source (not sink) for CO2, but it could burn - making a huge "burp" of CO2 but even worse: high clouds with fine soot - I.e. great increase in solar heating - throwing Earth into thermal run-a-way start in about a week! ** I bet that there are other rapid processes, not I or anyone, have thought of. After all the transition is an inherently unstable positive feed back driven process. I am reminded of man's POV 50 years ago about how easy it should be to hold a fusion plasma in a magnetic bottle. - Well it wasn't - We still can't but we now know about 30 different instabilities mother nature knew of all along that lets the plasma do what it wants too instead of what man hopes for. I don't think this is exactly what Guy MaPherson had in mind, but it might have been, when he named his blog about near term extinction (by 2030): "Nature Bats Last."
It's not a 'stretch' to call it endothermic, it is endothermic - the reaction absorbs energy from its surroundings. The difference between them being that Hansen's predictions were made using the grey-body approximation, which Hansen has since admitted is wrong, and Kasting's predictions were made using the CKD method which Hansen has since admitted was more accurate. The grey radiator model approximates the atmosphere as being a greybody surface radiating at some altitude and proceed with your calculations from there - this is the approach that was used by Hansen and part of the reason he made the predictions he did. The alternative approach uses the spectral lines of atmospheric gasses binned into wavebands with absorption coefficients assigned to each waveband, which can then be adjusted - this is the approach that was used by Kasting and makes different predictions As I mentioned earlier, I was (at one stage) trying to build a CKD model myself. I don't see that as being a lack of confidence in the answer - I would include those same considerations in any similar paper I wrote purely because I consider them neccessary for a full and complete paper. Kasting had the same thing to say in 1988. Are you beginning to accept that you may have been wrong to simply dismiss the paper based on its age?
Yes I agree and concluded by saying: "but it is endothermic" - it just seems strange terminology when the energy supplied is not thermal but as in my example come from a very non thermal source - a cosmic ray's dynamic electric field impulse - don't you agree something like "energy absorbing" is a more accurate, less strange, way to call these non- thermal energy inputs, than endothermic? I doubt that bold part if your were fully confident in your papers conclusion. If your paper concluded ice floats, even if very cold and thus contracted, and that is very important for continuation of life on earth. Are you now claiming you would include a section on how to be warned if ice density vs. water started to increase and another section on what man might be able to do about that possibility? But we don't need to infer the authors are uncertain their conclusion is solid fact - they directly tell us it is not: "because of the extreme seriousness of the consequences, this theoretical answer is insufficiently satisfying. Whilst we can construct simple models to describe the limits of how the atmosphere behaves (and verify them with numerical calculations to an extent), we actually have little idea of exactly how the atmosphere will change when subject to extreme heating. Is there any missed physics or weak assumptions that have been made, which if corrected could mean that the runaway is a greater risk? We cannot answer this with the confidence which would make us feel comfortable." I may be more inclined than most to "think out side the box" (In fact was often called in on "tiger teams" working on a sick satellite even though I knew "diddly squat" about the satellite because of that characteristic - and fact my ignorance allowed me to ask questions the others knew were stupid, but got them thinking on another line / approach.) Thus one of those "missed physics" might be the process I noted at end of last post (Briefly: very dry Amazon fully buring with fine soot pumped up to darken high clouds via the rising Hadley cell convection.) You yourself noted in recent post that mother nature is quite resourceful - finds way to do thing man did not think of. With more than 31 known positive feed backs to work with - I bet she can come up with more than one way to make a run away to lethal state possible - There are many much cooler than going all the way to the Venus like hot stable state. To continue quoting from their next paragraph: "How relative humidity will change with warming is very poorly understood, but will have a first order effect on temperature change. Explicit inclusion of a hydrological cycle in models has given rise to multiple equilibria (Renn´o, 1997), which adds an additional threat. Likewise, we have not discussed clouds (the physics is hard enough without them). Presently, the greenhouse effect of clouds is about half the albedo effect." - Fine black Amazon soot in high clouds probably is able, from this 50% of the albedo and other comments in their paper, to start the transition to one of these "additional threats" I. e. Make Near Term Extinction in 10 days! Funny think about exponentials - you don't even notice them when they start, but kill you quick in their end. To close this post, I give one final quote from the article:
Endothermic is perfectly adequate as it is usually used to mean energy absorbing rather than neccessarily heat absorbing - in this case though, decaying clathrates are going to absorb heat. Congratulations on your promotion to god-hood. If there was some 'thing' in my paper that suggested that it might be a possibility, sure, as far as I'm concerned not covering the possibility would be bordering on negligence. A seperate issue - this is not the justification you used and it was the justifaction you used that I was objecting to.
I'm sorry to have confused you - I have no intention or consciousness of doing any "defaulting" to any of those three positions. The only positions I hold are those I actually claim here, in words. Yes. We know. That may be why nobody is claiming any such necessary truth. Returning to my interest and posting: we have a large number of reassurances regarding a methane feedback burst, but they are based on invalid arguments, overlooking of central issues, etc. We have no reassurances based on sound logic and reliable assumptions. They may exist, in which case one wonders why all the reassurances omit mentioning them, or they may not, in which case the calculation of the likelihood, the odds, becomes urgent. That one was based on an assumption of ocean floor heat conveyance by diffusion only - as noted then, that assumption is not safe or reasonable. But I'm abandoning my search. There are no such calculations floating around, , apparently, and I am incapable of doing them for myself.
Whatever- I don't actually give a crap one way or the other - it's wholy irrelevant, and nothing to do with my omission of your input to the conversation in my characterization of the exchange between Billy T and Billvon. I mentioned a logical fallacy at one stage - no simple answer, or something along those lines. Was it? Maybe you need to take a closer look. Tell me, have you look at any of the 13 or 14 papers and articles I posted links to, or have you just ignored them? Unless the results are confirmed by subsequent work that doesn't make that particular assumption. More's the pity.
Perhaps ocean permafrost may lag behind landbased permafrost. It seems that we ar experiencing unusually large methane releases in Siberia.
We currently have a “safety margin” of 300 – 240 = 60W/m^2 – see text at end, assuming their analysis is correct, as I will for this post; but they note several things not considered in the analysis that could make their conclusion wrong. One, about hot moist atmosphere dynamics being mention in the Conclusion and several others in the body of the paper; the most important, I think, is the total neglect of cloud effect details. That is what this post will focus on. I. e. I will discuss the inverse of the last sentence, now bold, of their conclusion, which I reproduce in full at end of this post. In this post I provide numerical analysis showing how that “abolishing of the safety margin” can occur; but first I note that all agree that continued increase of the CO2 concentration (now about by 3% annually) leads to certain extinction of human life – Different experts answer the question as to when differently but all agree it will happen. Some say as soon as 2030, others say not before 2100. This extincion with continued 3% CO2 concentration increase occurs even without thermal run-a-way as the paper of the link notes: More atmospheric CO2 increases the surface temperature even though the maximum IR escaping Earth (in their and most models) does not increase. I. e. All will die with wet bulb temperature of ~ 35C even if full thermal run-a-way does not occur. - It is not possible to over state the importance (from human POV) of man-made global warming. As I noted in prior post there exist a natural process, quite plausible in my opinion, if not highly probable assuming present drought conditions continue, that the current 60W/m^2 safety margin might be totally abolished. I. e. the absorption of solar energy might be significantly increased by an increasingly common natural process – forest fires. Please Register or Log in to view the hidden image! Note that where warm air is rising even this diagram shows high altitude clouds form. If the since 2005 drought in the Amazon continues, for a few years more, not only will the Amazon be a net source (not sink) for CO2, and thus accelerate the surface temperature increase, but it could burn - making a huge "burp" of CO2 but even worse: high clouds with fine soot – I. e. a great increase in solar heating - throwing Earth into the start of a thermal run-a-way process in about 10 days! The Jan 2012 paper gives Earth's albedo as 0.30 and notes that if it should fall to 0.16, then thermal run-a-way is to be expected. It also notes that clouds, which were not explicitly considered in their analysis do 50% of the reflection of incident solar energy. They have much higher albedo, especially the high altitude clouds: Please Register or Log in to view the hidden image! Thus I take the clouds formed by the very moist tropical Hadley cell up welling as with albedo of 0.55, but normally it is less than 100% cloudy; however, if the Amazon were to burn the cloud cover, all the way around the earth at top of the Hadley cells would be essentially 100% with cloud cover and with much lower albedo due to the air born fine soot. “ The largest cells extend from the equator to between 30 and 40 degrees north and south, and are named Hadley cells... ” From: http://www.metoffice.gov.uk/learnin...how-weather-works/global-circulation-patterns The average cloud cover is now at least 50% in the Hadley zone, so I will consider only one of the two Hadley zones having 100% of its area with Albedo of 0.55 and is thus reflecting 0.55x300W/m^2 incident up on its area, which is about 30% of earth's total area. Thus Earth's 0.30 average albedo can be considered to be due 0.30x0.55 + 0.70xY where Y is the average albedo of all the earth's area except for that covered by the one Hadley zone with albedo of 0.55 or Y = (0.30 – 0.3x0.55) / 0.70 = 0.193 So under normal conditions, Earth's albedo, a, is approximately: a = 0.7x0.193 + 0.3x0.55 = 0.30, but if soot has reduced that to 0.16 we have: 0.16 = 0.7x0.193 + 0.3xZ or Z = 0.083 which is a quite black albedo (non reflective) barely possible for fire's soot deposited on a mirror, but large compared to “lamp black”. Note however, a cloud, especially a high altitude one, is not a simple surface. Certainly very different from a metal mirror. Almost all of a clean cloud's reflectivity is the result of MANY small angle scattering as “forward scattering cross section” (Scattering angle small compared to 90 degrees.) is much greater than “backward scattering cross section.” Thus, the reflection by a clean cloud is a "biased random walk" * thru angle space with many small angle scatterings. Each of which could absorb the photo if it is incident on the surface of a soot particle. I. e. a very tiny fraction of soot content will make the albedo of the cloud essentially zero! My main point being that large part of the Amazon burning could drastically reduce or totally abolish Earth's current (by the link below's calculation) “safety margin” in a very short period. Also, other fires are already lowering the albedo of high albedo surface, like Greenland's ice cover. See photo of this in post here: http://www.sciforums.com/showthread.php?97892-Climate-gate&p=3217548&viewfull=1#post3217548 I have not tried to do the calculation, but soot added each year to ice and snow covered surfaces may be as important in driving global warming as the 3% annual increase in CO2, which the IPCC does consider. CO2 is already blocking the escape of more than 50% of all it can - but soot lowering the albedo of high albedo surfaces has a long way to go before its effect on global warming saturates, as CO2 is now approaching! ---------------- * The bias is for the typical scattering to send the photon deeper into the cloud, but if it is not absorbed and the cloud is thick, it will get out of the top eventually - prehaps after 50 or so scatterings. I have worked with commercial Sodium Iodide scintillation crystals to detect and gamma rays. Typically they are cylindrical with single photomultiplier tube bonded to one end of the cylinder, but when the gamma ray passing thru the crystal scatters and produces visible light,most of the light does not go directly to that detector. Instead it leaves thur some other surface of the crystal and must be very efficiently diffusely reflected back many times until it does enter the photomultiplier tube. The best metallic mirror is vastly inferior as a reflector to less than half a cm think layer of very clean small crystals surrounding the scintillation crystal - I. e. the reflection is just like that a clean cloud, but of course perfectly clean clouds do not exist. The higher ones are cleaner than the lower ones and can reflect even 2/3 of sun light away from Earth but the photon that eventually escapes many have been dozens of meters deep inside the cloud before doing so - scattering more than 90 degrees. Conservation of momentum is why the bias favors small angle scattering. - I.e. then the heavy scatter needs extremely small acceleration but 180 degree back scatter must give the scatter twice the momentum the photo had - very hard for a photo to transfer that much to scatter. In most scatterings the photo loses little moment and continues on deeper into the cloud. 6. Conclusion {of Jan 2012 paper with nothing deleted or changed from http://arxiv.org/pdf/1201.1593v1.pdf } The runaway greenhouse is well defined in theory: As the surface warms, the atmosphere becomes optically thick with water vapour, which limits the amount of thermal radiation which can be emitted to space. If the planet absorbs more solar energy than this limit, runaway warming ensues. The practical limit on outgoing thermal radiation occurs when the atmospheric structure tends towards the saturation vapour pressure curve of water as the atmospheric composition tends towards pure water vapour, giving a limit of around 300Wm−2. Earth presently absorbs around 240Wm−2 of solar radiation. Increasing carbon dioxide concentration will make surface warmer with the same outgoing thermal flux. Following this theory, we are not near the threshold of a runaway greenhouse. However, the behaviour of hot, water vapour rich, atmospheres is poorly understood and much more study of these is necessary. In the event that our analysis is wrong, we would be left with the situation in which only geoengineering could save us. The only useful methods would be those which would reduce the amount of solar energy that the Earth absorbs.
I not only looked at it, but responded to it, noting the problem with the assumption - unless we're talking about two different links here, as more than one makes that assumption in estimating how much overall planetary warming it would take to affect the clathrates in the ocean, under the permafrost, etc. Invalid assumptions remain invalid. Work that makes other invalid assumptions, overlooks other central issues, or errs in argument in other ways, does not "confirm" anything regardless of matching results. That's kind of the point: a large batch of papers and articles none of which present valid arguments based on reasonable assumptions and relevant evidence is no better reassurance than one such - in fact, worse: each new one on the stringer increases the odds that the pool from which they are drawn contains no other fish.
Sometime ago (and I may have posted here too) NOAA wanted to set up a SCADA of the entire planet. I could not find anyone to bid with and hence ignored it. May be they already have and checked the climate change dynamics. I was told, as of July that the tipping point has been passed...hence wait till Florida goes under....
Yes, here's evidence that what you've been told could likely be true (tipping point reached): http://www.breitbart.com/Big-Government/2014/08/29/Democrats-More-Afraid-of-Global-Warming-Than-ISIS More worried about Florida 'going under', than very real flood of illegals swamping the country as we speak.
No, I posted it to let you know the environment you've enjoyed allowing you to think/'live' in la la land is fading fast.
Please Register or Log in to view the hidden image! Consider the postings of this place in the aggregate... fail... Please Register or Log in to view the hidden image!
Hey, Breitbart's back in a science thread! - (he's overdue, in the standard Republican amnesia rehab - did it take longer to clean him up due to the nature of his living corruption, or were the usual rehab methods delayed by his very timely death?) The zombie operation lacks the master's touch, though - the inclusion of the results for the Independents in the linked poll is an unforced error Breitbart probably would have avoided. The zombies may be operating on the general principle that Independents are stealth Republicans in such polls, automatically on the right side, but Breitbart sweated the details.
On what grounds do many here justify their arrogance, self confidence, and pontificating concerning so much (pertaining to 'reality' as they think they know it) when unforeseen surprises like this occur relatively frequently?
But now you are assuming that this amount of leakage has been the same all along. IMO, that is a hasty conclusion and dismissive of known evidence of an increase in methane emissions from the earth's perma-frost in many other places due to GW. Siberia? . This does not mean we did not have any previous data on methane emissions of the US Atlantic margin. Is it not possible that we were not aware of this increase in methane release at these locations because it is relatively recent and a result of GW?
