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Comments 102451 to 102500:

102451. michael sweet at 23:08 PM on 4 December 2010
        Renewable Baseload Energy
        My position on nuclear has shifted more negative due to Peter Langs postings. I am still agnostic since I know other people who think it is a good idea. If Peter's arguments are the best nuclear can do it is not worth much. I find Peter's posts to be riddled with inaccuracy and I now presume anything he says is factually incorrect unless another poster supports him. This thread and the "what should we do about renewables" thread both essentially devolved into Peter insulting everyone else after he came on. It is too bad, they were both good threads before Peter came on.
102452. Ned at 22:37 PM on 4 December 2010
        Positive feedback means runaway warming
        Leland Palmer writes: How likely is all of this? You've written that very coherently, and it's not by any stretch of the imagination a "crackpot" scenario. But I would say it's very unlikely, even under a BAU emissions scenario. Lord knows I'm no expert on the PETM, but achieving that kind of CO2 pulse would seem to require burning more fossil carbon than would be projected even under an extreme scenario. And my understanding of the benthic methane hydrate issue is that it's likely to kick in only very slowly (on a global scale, ignoring local exceptions). The PETM was certainly nasty, and we wouldn't want to subject ourselves to anything like it. But it didn't lead to the kind of Venusian runaway warming you describe, despite involving much higher temperatures than AGW is likely to produce (remember that in addition to the large magnitude of the warming, the PETM was starting from a warmer point). Yes, the sun is hotter now, but the PETM-Holocene difference in TSI isn't that large (a couple of percent?). Perhaps most importantly, there have been other periods in the past (not just the PETM) when the planet was much hotter than today (think crocodiles and azolla blooms in the Arctic) and no Venusian runaway occurred. On very long timescales (tens of millions of years), the earth has been gradually cooling. We're going to be unwinding that process by at least a couple of degrees C in a geologically very short time ... but I think the dangers more involve disruption of our agricultural system, expensive and painful impacts from sea level rise, and loss of biodiversity (esp via ocean acidification). I don't think the Venusian runaway is remotely likely unless our descendants tried really hard to bring it about. (E.g., massive production and release of CFCs). Again, though, paleoclimate isn't really my area of expertise, so this is just one person's amateur understanding.
102453. HumanityRules at 22:22 PM on 4 December 2010
        The human fingerprint in the seasons
        44 Albatross So fingerprint = correlation? Is that all? Wow. Anyway I managed to get side tracked onto solar variance. There's a huge review of it here. http://www.agci.org/dB/PDFs/10S1_LGray_SolarInfluencesCLimate.pdf There are numerous references to a link between solar variance and winter warming trends which seem to contradict "If global warming was driven by the sun, we should see summer warming faster than winter.". It looks like observational based correlations of solar cycle variance are better at identifying a winter warming trend than one in summer. There's plenty of interesting points in that review to get both sides of the argument excited.
102454. Rob Painting at 22:16 PM on 4 December 2010
        Ocean acidification isn't serious
        Chris Shaker @17 Please search for 'Iron Fertilization' in this paper to see that iron is well recognized as a limiting factor in plankton growth Well aware of that thanks. Sorry, but "iron fertilization" is one of those ill-considered "engineering" ideas: Can ocean iron fertilization mitigate ocean acidification? " Here, using a global ocean carbon cycle model, we performed idealized ocean iron fertilization simulations to place an upper bound on the effect of iron fertilization on atmospheric CO2 and ocean acidification. Under the IPCC A2 CO2 emission scenario, at year 2100 the model simulates an atmospheric CO2 concentration of 965 ppm with the mean surface ocean pH 0.44 units less than its pre-industrial value of 8.18. A globally sustained ocean iron fertilization could not diminish CO2 concentrations below 833 ppm or reduce the mean surface ocean pH change to less than 0.38 units. This maximum of 0.06 unit mitigation in surface pH change by the end of this century is achieved at the cost of storing more anthropogenic CO2 in the ocean interior, furthering acidifying the deepocean. If the amount of net carbon storage in the deep ocean by iron fertilization produces an equivalent amount of emission credits, ocean iron fertilization further acidifies the deep ocean without conferring any chemical benefit to the surface ocean"
102455. Rob Painting at 21:58 PM on 4 December 2010
        Ocean acidification isn't serious
        Chris Shaker, You have so many misconceptions about the topic, it's difficult to know where to start. The advanced version of Ocean Acidification should be out by years end and hopefully that clears up some of your confusion. Coral reefs - long term monitoring is showing a rise in bleaching events and coral death. Both acidification and ocean warming negatively impact coral reefs. Again, this is a topic for a later post but some reading: Caribbean Corals in Crisis: Record Thermal Stress, Bleaching, and Mortality in 2005 Worst coral death strikes at SE Asia - 19 October 2010 "Many reefs are dead or dying across the Indian Ocean and into the Coral Triangle following a bleaching event that extends from the Seychelles in the west to Sulawesi and the Philippines in the east and include reefs in Sri Lanka, Burma, Thailand, Malaysia, Singapore, and many sites in western and eastern Indonesia. “It is certainly the worst coral die-off we have seen since 1998. It may prove to be the worst such event known to science,” says Dr Andrew Baird of the ARC Centre of Excellence for Coral Reef Studies and James Cook Universities. “So far around 80 percent of Acropora colonies and 50 per cent of colonies from other species have died since the outbreak began in May this year.”
102456. Tom Curtis at 21:44 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        Bob, my discussions have covered the steady state. However, I am also not sure how important a distinction that is in the stratosphere in that, not lying next to any oceans, and being a rarified gass, the time interval between perturbation and adjustment to steady state would be quite short.
102457. cjshaker at 21:21 PM on 4 December 2010
        Ocean acidification isn't serious
        There is also a Wiki on Iron Fertilization of the Ocean http://en.wikipedia.org/wiki/Iron_fertilization "Perhaps the most dramatic support for Martin's hypothesis was seen in the aftermath of the 1991 eruption of Mount Pinatubo in the Philippines.[citation needed] Environmental scientist Andrew Watson analyzed global data from that eruption and calculated that it deposited approximately 40,000 tons of iron dust into the oceans worldwide. This single fertilization event generated an easily observed global decline in atmospheric CO2 and a parallel pulsed increase in oxygen levels.[7]" Chris Shaker
102458. cjshaker at 21:15 PM on 4 December 2010
        Ocean acidification isn't serious
        Please search for 'Iron Fertilization' in this paper to see that iron is well recognized as a limiting factor in plankton growth. They are talking about using Iron to cause plankton blooms to sequester CO2 and drop it down to the ocean floor http://www.cephbase.org/refdb/pdf/8122.pdf That paper also seems to show that mortality rates for some sea creatures, such as mollusks, increase with CO2. Chris Shaker
102459. cjshaker at 21:04 PM on 4 December 2010
        Ocean acidification isn't serious
        The paper I referenced, showing plankton growth limited by iron was from Nature "We conclude that Fe deficiency is limiting phytoplankton growth in these major-nutrient-rich waters." http://www.nature.com/nature/journal/v331/n6154/abs/331341a0.html Chris Shaker
102460. cjshaker at 21:00 PM on 4 December 2010
        Ocean acidification isn't serious
        Your link to a nature article does not appear to work http://www.nature.com/nature/journal/v466/n7306/abs/nature09268.html%3Cbr%20/%3E Did you notice the paper I referenced, showing plankton growth limited by iron? Chris Shaker
102461. cjshaker at 20:57 PM on 4 December 2010
        Ocean acidification isn't serious
        Rob Painting: Did you read the paper I referenced, showing increased biomass in coral with increased CO2? Did you read the paper I referenced, showing increased plankton growth with increased CO2? Are you offering me any peer reviewed papers proving the opposite? No. Chris Shaker
102462. Rob Painting at 20:48 PM on 4 December 2010
        Ocean acidification isn't serious
        This paper leads one to believe that it is not as simple as the AGW believers want us to believe You're arguing a strawman there. Changes in seawater chemistry are anything but simple. Would we not expect the ocean equivalents of plants to also grow more as the CO2 increases as well, providing more food for sea life? No. Decreased carbonate concentrations in seawater, combined with acidification and ocean stratification affect the long-term viability of phytoplankton populations. For example: Global phytoplankton decline over the past century "Here we combine available ocean transparency measurements and in situ chlorophyll observations to estimate the time dependence of phytoplankton biomass at local, regional and global scales since 1899. We observe declines in eight out of ten ocean regions, and estimate a global rate of decline of ~1% of the global median per year. Our analyses further reveal interannual to decadal phytoplankton fluctuations superimposed on long-term trends.
102463. cjshaker at 20:10 PM on 4 December 2010
        Ocean acidification isn't serious
        This paper leads one to believe that it is not as simple as the AGW believers want us to believe. Increased CO2 does seem to decrease CO3 in the lab, which is considered a limiting factor for coral growth. But, it also increases photosynthesis output, and actual coral growth in terms of biomass does not seem to suffer, and actually increases in some studies http://www.isse.ucar.edu/staff/kleypas/docs/PUBS/kleypas_langdon_icrs_2000.pdf More information http://scienceandpublicpolicy.org/images/stories/papers/originals/coral_co2_warming.pdf Are they trying to measure coral growth the wrong way when they concentrate on calcium carbonate measurements? Would we not expect the ocean equivalents of plants to also grow more as the CO2 increases as well, providing more food for sea life? Yes, plankton growth will be stimulated by increased CO2 levels, as long as other limiting factors do not come into play http://epic.awi.de/Publications/Tor2008b.pdf Another paper I scanned said that parts of the ocean are deficient in iron, which limits plankton growth http://www.nature.com/nature/journal/v331/n6154/abs/331341a0.html Plankton and algae will increase productivity as CO2 levels increase in seawater, they die, raining down on the sea floor, sinking more CO2. Chris Shaker
102464. Joe Blog at 20:09 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        Bob Guercio at 07:45 I think Tom and Spaceman have covered your questions as well as i could have(truth is, most of my posts on this thread have been "trying" to convey the mechanisms alluded to by the radiative exchanges in that paper.) And the existence of the tropopause itself, is pretty convincing evidence that this is the main phenomena responsible for stratospheric cooling/energy loss.
102465. Bob Guercio at 19:36 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        Tom, Just one more point. Do your discussions here cover the transient state, the steady state or both. We are in the transient state now because more energy is reaching the earth's surface than that which is leaving. Let's assume that we miraculously stabilized atmospheric CO2 concentration today. The temperature of the earth will continue to rise until the output energy from the earth equals the input energy. That would be the steady state. I'm not talking about energy coming in and out from beyond the thermosphere. I'm talking about the ground. I meant my blog to be strictly for the steady state. Bob
102466. Billhunter at 19:12 PM on 4 December 2010
        A basic overview of Antarctic ice
        Albatross at 09:42 AM on 4 December, 2010 Hi Bill, "Umm, no. I'm afraid that you seem to have completely missed the point of that statistical analysis exercise. Anyhow, the graph @89 is the net result of all the changes/processes and it is showing a distinct downward trend in global sea ice since about 2001." I looked at your post #74 and did not see the test of statistical significance applied to global sea ice Albatross. Since it appears to be statistically insignificant it probably either is or very close to it.
102467. Tom Curtis at 17:38 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        It occured to me to use Ramathan and Dickson, 1999 and the version of MODTRAN at David Archer's website to better characterize the relative importance of the two effects we are discussing. Using Modtran with a lookdown altitude of 10 km on the 1976 US Standard Atmosphere, I determined the difference in outgoing radiation between an atmosphere with 375 ppm and one with 750 ppm of CO2 at approximately 3.25 w/m^2. From Ramathan and Dickson, the IR absorption by CO2 + H2O in the stratosphere is 19 w/m^2, and IR emission in the stratosphere is roughly 35 w/m^2 (Table 3); a difference of 16 w/m^2. Doubling CO2 will double both absorption and emission, to a first approximation, giving values of 38w/m^2 and 70w/m^2, and a difference of 32 w/m^2; making the net difference if there were no change in radiation from the troposphere 16 w/m^2. Introducing that change, the reduction in IR absorption will not excede the reduction in outgoing IR from the troposphere, and so will not excede 3.5 w/m^2. Subtracting that value from the stratospheric absorption, and then doubling for the increased CO2 concentration yields a minimum absorption of 31 w/m^2, and a net difference for doubling CO2 of (at most) 23w/m^2. Therefore the maximum cooling introduced to the stratosphere by shielding the stratosphere at some frequencies of IR is about 7 w/m^2, compared to a 16 w/m^2 from simply doubling the CO2 in the stratosphere. For comparison, the cooling introduced by redusing stratospheric ozone by 30% is about 5 w/m^2, or about 3 w/m^2 once we allow for reduced IR emissions by O3. I must emphasise that these are ballpark figures. However, we can reasonably conclude that the cooling of the stratosphere because of reduced IR emissions in the 15 micron band has a similar cooling effect to that of ozone reduction, and that the cooling effect of doubling stratospheric CO2 is 2 to 4 times as strong as that. Two additional points. First, it is evident that the as CO2 concentrations increase, the relative importance to the thermodynamics of the stratosphere of Ozone will decrease. This is quite apart from any changes in ozone concentration induced by temperature changes (which may be quite significant). Second, an additional important effect on stratospheric temperatures is albedo variations, with higher albedo resulting in higher stratospheric temperatures. This is a dominating effect following major tropical volcanoes, but probably less significant than other factors discussed here at other times. Finally, thankyou for the offer, Bob, but no thanks. I would much rather you got Gavin to review your rewritten blog. An expert is somebody who knows how to avoid fundamental errors. In this field, Gavin is an expert and I am not. So no matter how sound my reasoning appears to me, it is always possible I am overlooking something completely obvious.
102468. Andy Skuce at 16:57 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        I'm not sure whether Science of Doom's website has been referenced yet on this thread but there are two articles in particular there that people here may find useful. I certainly did. Stratospheric Cooling Tropospheric Basics
102469. Leland Palmer at 16:24 PM on 4 December 2010
        Positive feedback means runaway warming
        This is a very interesting and informative article, and I thank the author for it. Respectfully, however, I think that readers might jump to a false or questionable conclusion reading this article, because CO2 is only a piece of the climate change problem. What Hansen envisions, I think, in his runaway climate change scenario is a series interlinked positive feedback effects which in total might be sufficient to tip the earth into runaway warming. He very specifically mentions destabilization of the methane hydrates as part of his runaway scenario, for example. I can't speak for Hansen, but what I worry about is the scenario below. Increases in fossil fuel produced CO2 cause warming, which activates the following positive feedback processes: The Arctic sea ice/ albedo feedback. The permafrost decay feedback. The forest wildfire feedback. The ocean CO2 release feedback. The destabilization and release of methane from the shallowest methane hydrates including the Siberian yedoma and thermokarst. Atmospheric increases in water vapor. The combined effect of all of these processes destabilizes the oceanic methane hydrate deposits starting with the shallowest ones first. Most methane from this release ends up dissolved in the sea water, and oxidized into CO2. Increasing amounts are able to vent directly to the atmosphere through sudden releases. Destabilization of the hydrates also results in associated deposits of natural gas venting directly into the atmosphere. Most of this takes place in the Arctic, while the Antarctic continues almost intact. Due to the fact we are coming out of an ice age, large inventories of methane hydrates are available. As methane releases accelerate, concentrations of the hydroxyl radical in the atmosphere plummet, leading to longer residence times for methane in the atmosphere before it is oxidized into CO2, and increased warming as a result. About this time, CO2 based warming is approaching a first plateau, as this article predicts, due to diminishing positive feedback returns and saturated absorption bands. So, we get maybe 10 degrees C of temperature increase due to maybe 3000 ppm of atmospheric CO2. But methane impact on global heating has its own diminishing returns curve, and that curve is in its steepest part. Water vapor concentrations continue to increase, and the diminishing returns curve of water vapor is also near its steepest point at this time. The diminishing returns curve of CO2 is at a plateau. When the diminishing returns curve of methane and water vapor plateau, the earth is perhaps another twenty degrees C warmer, on top of the ten degrees C caused by CO2 alone. At this point many inland lakes lose their water to the atmosphere. Evaporation is greatly increased, from the landmasses. About this time, the oceans have heated enough to release most of the methane from hydrates. The oceans become anoxic, and hydrogen sulfide starts to evolve from the oceans, killing most land organisms. The hydroxyl radical has been overwhelmed, and atmospheric oxidation times for methane have become hundreds of years. The oceans begin to boil, and transfer their water into the atmosphere. Soon, most of the water in the oceans has transferred to the atmosphere. As ground temperatures increase, carbonate begins to convert to CO2. Plate tectonics, driven by the temperature difference between the mantle and the surface slows and stops. So the rock weathering cycle and subduction of carbon containing sediments also stops. Eventually, with all of the water, CO2, and methane in the atmosphere, the earth becomes another Venus, but hotter at first because we still have all of our water, while Venus has lost its water due to light induced dissociation of water into hydrogen and oxygen, and loss of the hydrogen into space, as happened on Venus. How likely is all of this? Well mass extinction events such as the Paleocene-Eocene thermal maximum have apparently taken us part way down this path, according to isotope ratio records. And the sun is hotter, now.
102470. archiesteel at 16:16 PM on 4 December 2010
        Renewable Baseload Energy
        @Peter: I concur with others, here. You are the one who started with personal attacks, by suggesting that anyone who was in favor of renewables was an idiot. Seriously, you are a *terrible* salesman for nuclear energy. You have likely done more harm than good to your own cause - that alone should be reason for you to pause and reflect on what's the best way to sell nuclear to a hesitant public (hint: it's not what you're doing right now).
102471. Bob Guercio at 15:58 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        In any case, my hat is off to you for wading through it all! Thank you but not just yet. I'll go through it tomorrow and I will probably understand it. It's still a little fuzzy but I'm pretty confident that I will get it. It's good that I posted the blog that I did. How else would I have fleshed this problem out. I think that now I understand Gavin's email to me. I'll repeat it here and comment: mostly right. You miss two key facts. First, all GHGs emit as well as absorb, and whether you will get warming or cooling in a region depends on the ratio of the change in absorption and the change in emittence. Second, the troposphere has many IR absorbers, the stratosphere only two (CO2 and O3 - everything else is minor). So the impact of CO2 above the tropopause is amplified. Otherwise you are spot on! Gavin See the first part. That is Gavin's short version of everything you guys have said. And then his comment that I was "spot on". I was "spot on" with that one mechanism but there is so much more to it. Thanks again but I really don't expect this thread to end just now. There's just too much to it and I'm sure that half the world is reading it and wants to understand it also. In the field of amateur climatolgy, my guess is that this is one of the most difficult concepts to grasp. I would like to have another go at writing a more comprehensive and accurate blog on this which is needed on the Internet. However, credit where credit is due and you guys have to be included. Please email me to discuss it further. robertguercio@optonline.net
102472. Spaceman Spiff at 15:11 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        Bob Guercio -- Another point of clarification. The 15 micron spectral feature I have been referring to in previous posts is the *very central-most spike* shown in this figure of transition probability of CO2 (for a particular value in temperature and pressure). Most of the CO2 spectral feature that you see in Archer's upwelling radiation spectrum of Earth, and that has been under discussion throughout this post, lies in the 13.5-17 micron region of the transition probability figure.
102473. Spaceman Spiff at 14:57 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        Bob Guercio -- If there is anything more that you'd like me to clarify, please ask. You left a few questions for me, but I think Tom Curtis might have answered most of them. Similar to Tom, I would say that the initial explanation was significantly incomplete. At the same time I am still uncertain whether all the important pieces have yet been identified. In any case, my hat is off to you for wading through it all!
102474. KR at 14:45 PM on 4 December 2010
        Renewable Baseload Energy
        Peter Lang - "Address your comments first to the scaremongers and renewable energy zealots who continually make their personal attacks to defend their beliefs, then I may take some notice" Oof. Peter, I suggest you go take a good look in a mirror. Counting posts, the majority of personal attacks in this thread come from you. After 2-3 exchanges you started posting you have done nothing but insult everyone else here. Even when (as I have) some have agreed with aspects of your postings. You may have excellent points in some particulars. But arrogant, insulting, and overall horrid behavior guarantee your input will be ignored. Sometimes the messenger overrides the message - you are succeeding in that. I only hope you are aiming to be tuned out.
102475. actually thoughtful at 14:36 PM on 4 December 2010
        Renewable Baseload Energy
        Quokka - would you pay $50 per month to eliminate global warming?
102476. Tom Curtis at 14:26 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        Bob @122, everywhere where I say "atmosphere" in comment 120, you can substitute "stratosphere". It is not that atmosphere is wrong, so much, as that stratosphere is more specific. "The same radiation enters the stratosphere so I guess this means that twice as much energy would be taken out of the IR radiation since there are twice as many CO2 molecules to absorb it. Correct?" Yes. "I must ask you the same question that I asked Space Spiff. Are you saying that my mechanism is wrong or that it is one of several mechanisms and may not even be the dominant mechanism?" Essentially correct. Rather than saying it "... is not even the dominant mechanism", I would rather say it is probably not the dominant mechanism (from my understanding). Further, I think it is important to be aware that the mechanism you describe is only a cooling mechanism because the stratosphere is warmer than the upper troposphere. It is like playing boiling water (100 degrees C) through a fire hose onto some object. Is it a warming or a coolinig mechanism? That depends critically on whether the object you are drenching is a block of ice or several tonnes of red hot steel! Your mechanism is like reducing the temperature in the water in the hose by 10 degrees C. That will reduce the rate at which ice being drenched would warm, and increase the rate at which the red hot steel, being drenched, would cool. But I am unsure that calling it a cooling mechanism is informative.
102477. quokka at 14:21 PM on 4 December 2010
        Renewable Baseload Energy
        $10,000 Electric Car? If Tata can pull this off with the capabilities mentioned at anything like this price, I would rate this as very good news indeed. This is a very good example of why electricity prices need to be kept as low as possible - to encourage migration from fossil fuels. With electricity prices two or three times higher, the running cost advantage of EV would be significantly eroded.
102478. Ned at 14:07 PM on 4 December 2010
        Renewable Baseload Energy
        Peter Lang writes: [...] the scaremongers and renewable energy zealots who continually make their personal attacks [...] The lack of self-awareness here is simply mind-boggling.
102479. quokka at 13:48 PM on 4 December 2010
        Renewable Baseload Energy
        Here is the IPCC AR4 assessment of CO2 emissions by electricity generation source, which we must assume was prepared by means of a comprehensive survey of the available authoritative literature.
102480. kdkd at 13:42 PM on 4 December 2010
        Renewable Baseload Energy
        PL #335 "Yea. Yea Yea Blah, blah, blah. Address your comments first to the scaremongers and renewable energy zealots who continually make their personal attacks to defend their beliefs, then I may take some notice. Otherwise I see it as simply the bias of the leanings of those who inhabit this site." I'd be inclined to take you more seriously if you didn't 1. Make the kneejerk accusation that everyone automatically opposes all of your ideas is clearly ideologically flawed. 2. That you'd actually answer the reasonable questions asked of you rather than either ignoring them, or making the accusations as in (1) Assuming that you do have some expertise in this area (and I have serious reservations that you have failed to challenge your own assupmptions properly, but it does appear that you posess important background knowledge about a large proportion of this topic), then it would be nice to be able to make use of them to understand the area properly, but the issues above render this impossible.
102481. Bob Guercio at 13:32 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        As I'm putting the pieces together, I'm starting to think that this is a terribly difficult thing to explain simply!
102482. Bob Guercio at 13:31 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        Bob, I don't know if this helps, but you seem to be thinking of the interactions as entirely a radiative story. In fact, it is a radiative/colissional story. Instead of: UVin + IRin = IRout, we have: UVin + IRin + Collisionalin = IRout + Collisionalout. Understood. In the stratosphere, for O3, UVin >> IRout > IRin; so O3 is a net absorber of radiation, with the excess energy being distributed to other components of the atmosphere by collission. You say atmosphere but I think you mean stratosphere. Am I correct? If this is the case, I think I understand. With CO2, IRout >> IRin, with UVin being zero. The energy defecit is drawn from the surrounding atmosphere by collisions. Again, I think you mean stratosphere? If we simply doubled the CO2 in the stratosphere, leaving that in the troposphere untouched, then initially IRout and IRin would double. The same radiation enters the stratosphere so I guess this means that twice as much energy would be taken out of the IR radiation since there are twice as many CO2 molecules to absorb it. Correct? Because IRout is larger than IRin, that results in a net energy deficit which the CO2 draws from colisional energy, in the process cooling the surrounding atmosphere until a new steady state is reached. Understood. If we instead doubled the tropospheric CO2, leaving the stratospheric CO2 untouched, that would reduce IRin, again creating an imbalance restored by local cooling of the atmosphere. stratosphere? If we do the actually possible, and double CO2 at both levels of the atmosphere, both factors will come into play. However, I believe, the first has the larger effect. More importantly, the second is a cooling effect only because IRout larger than, or equal to IRin. If IRin >> IRout, as would be the case in the absence of O3, then doubling both IRin and IRout would have a significant warming effect, more than sufficient to compensate for the small reduction of IR radiation from the troposphere in the 15 micron band. I think I understand. I must ask you the same question that I asked Space Spiff. Are you saying that my mechanism is wrong or that it is one of several mechanisms and may not even be the dominant mechanism? I want to thank both of you guys for helping me understand a very complex process. As I said to Spaceman, my brain hurts but it hurts more now. Bob
102483. Peter Lang at 13:14 PM on 4 December 2010
        Renewable Baseload Energy
        Ned,

        (1) Many of us support both nuclear power and renewables. My expectation is that reducing our use of fossil fuels will involve increased reliance on nuclear and hydro and solar and wind and geothermal and tidal power and biomass and ... well, you get the point. But you seem to be at least as motivated by the desire to attack renewables as by the desire to promote nuclear.

        This nonsense about supporting nuclear and renewables is just that – nonsense. Its been the means used by the anti-nukes for the past 20 years to delay action and put all their effort into arguing for more funding fro renewables. It is simply a delaying tactic. Renewables are totally uneconomic except in remote locations and as a small contribution to grid generation in some locations. Just face up to the facts and stop trying to sugar coat renewables and penalise nuclear. If we removed all the impediments to nu clear and the support for fossil fuels, CCS and renewables, then nuclear would quickly provide most of our electricity as it does in France.

        (2) On a more personal note, the aggressively combative style of many of your comments here …

        Yea. Yea Yea Blah, blah, blah. Address your comments first to the scaremongers and renewable energy zealots who continually make their personal attacks to defend their beliefs, then I may take some notice. Otherwise I see it as simply the bias of the leanings of those who inhabit this site.
102484. Bob Guercio at 13:12 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        The answer to your first question is "yes". The up and down transition rate equations contain many terms (spontaneous radiative decay, radiative absorption, induced emission, collisional excitation and de-excitation, ....). Collisional excitation followed by radiative decay via a photon that escapes is an important process in the stratosphere. Radiative absorption is not dominant (excepting in the ozone bands and the central CO2 transitions very near to 15 microns). Answer: Understood. I am not sure I know what you mean by, "The energy in the absorbtive portion of the band has been depleted after going through the troposphere." Answer: In my blog the difference in the absorbtion band between figures 2 and 3. More of a chunk has been taken out of figure 3 because the CO2 level is higher. What you see in the main CO2 band isn't due to Beer-Lambert's law. What you are seeing is largely due to light emerging from the layer at which the optical depth (dimensionless measure of matter's ability to absorb or scatter light) has fallen to ~1 (the "photosphere"). Response: I think that you are talking about the chunk that I am talking about in my figures 2 and 3. Correct? We are talking about band saturation here. Aren't we? Also, just to clarify what you mean by "photosphere" If you are looking down at the IR spectrum from an altitude, the earth would be the photosphere for the portion of the spectrum correcsponding to the black body temperature of the earth. If part of the spectrum is due to blackbody radiation from an altidute of 3 miles, the photosphere for this would be that altitude of 3 miles. Correct? Deeper down, the optical depth is too large (the photon mean free path too small), and most of the light is absorbed (and "re"-emitted) locally. The thermal emission is very sensitive to temperature, in that higher T gas emits more strongly. So where in wavelength the atmosphere is most opaque, the emitting layer (photosphere) lies high up in the troposphere where the T is low and so the thermal emission intensity is also low. Where it is less opaque, it arises from deeper layers in the troposphere where T is higher and thus is the thermal emission intensity. Response: Understood. An exception to this is the set of very, very optically thick transitions of CO2 lying very near 15 microns. This is in the center of the band that I refer to as the absorbtion band in my figures 2 and 3. Isn't it? Here the atmosphere is so opaque (due to the strength/probability of the transition) that this light's effective photosphere lies up in the stratosphere, where T is substantially higher than in the troposphere below (due to O3 dissociation by UV sunlight). The escaping emission there is therefore brighter than in surrounding wavelengths within the surrounding CO2 transitions, and thus the sharp, narrow, reversal you see at 15 microns at the center of the main CO2 "trough". Response: Understood Does that help at all? Yes. But now let me try to put everything together. Also, are you saying that my blog is wrong or that it describes only one of many mechanisms and it is not even the main mechanism? My brain hurts!
102485. Tom Curtis at 13:04 PM on 4 December 2010
        The human fingerprint in the seasons
        Chris G @50, stratospheric cooling because of increased CO2 is largely related to improved efficiency of radiating away heat in the stratosphere. As the stratosphere is very dry, H2O does not contribute signficantly to that cooling. In fact, stratospheric H2O is increasing slightly which would contribute as a minor effect to the cooling, but that is because of H2O from jet exhausts, not because of the warming surface. The tropopause is not the location of radiative balance but the point of balance between energy brought from the lower atmosphere by convection and that introduced to the upper atmosphere by absorption of UV light. That is why the tropopause is very high in the tropics and very low at the poles.
102486. Tom Curtis at 12:58 PM on 4 December 2010
        The human fingerprint in the seasons
        Sphaerica @49, you are in fact quite correct, which is why I said only to a "first approximation". Having said that, if we (following the IPCC) use 1.2 degrees for in initial forcing for a doubling of CO2, and 2.8 for the equilibrium responce, then the ratio of expected signal from GH warming to that from solar warming is 8.4 to one. Larger sensitivities reduce this ratio, but larger sensitivities make denying significant threat from anthropogenic CO2 indefensible. Further, as my third point indicates, responce the water vapour responce to different forcings is not quite identical, giving us a clear signal even with relatively strong feedbacks.
102487. Ned at 12:57 PM on 4 December 2010
        2nd law of thermodynamics contradicts greenhouse theory
        Tom, it is gibberish. No "seems" about it. The fourth paragraph I kind of get -- damorbel is confused about the difference between emissivity and absorptance, on the one hand, and emitted energy and absorbed energy, on the other. The first two are unitless fractions, and the latter two are radiant fluxes. That confusion probably explains the seemingly erroneous conclusion about rising or falling temperatures. But the second paragraph? Yeah, it's nonsense. Let's try a few substitutions: "The salmon difference is indeed great but what that count for? Sure it indicates that the Estonia/marshmallow system is in considerable hypothermia. But the only significance of this is the nature of the hypothermia, which is precisely what we are talking about, the contradiction of platypus/unicorn 'badminton' and the 2nd Earl of Ambergris, exactly the OP topic of this thread." Does that make any more or less sense than the original? Hard to say!
102488. Tom Curtis at 12:45 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        Bob, I don't know if this helps, but you seem to be thinking of the interactions as entirely a radiative story. In fact, it is a radiative/colissional story. Instead of: UVin + IRin = IRout, we have: UVin + IRin + Collisionalin = IRout + Collisionalout. In the stratosphere, for O3, UVin >> IRout > IRin; so O3 is a net absorber of radiation, with the excess energy being distributed to other components of the atmosphere by collission. With CO2, IRout >> IRin, with UVin being zero. The energy defecit is drawn from the surrounding atmosphere by collisions. If we simply doubled the CO2 in the stratosphere, leaving that in the troposphere untouched, then initially IRout and IRin would double. Because IRout is larger than IRin, that results in a net energy deficit which the CO2 draws from colisional energy, in the process cooling the surrounding atmosphere until a new steady state is reached. If we instead doubled the tropospheric CO2, leaving the stratospheric CO2 untouched, that would reduce IRin, again creating an imbalance restored by local cooling of the atmosphere. If we do the actually possible, and double CO2 at both levels of the atmosphere, both factors will come into play. However, I believe, the first has the larger effect. More importantly, the second is a cooling effect only because IRout larger than, or equal to IRin. If IRin >> IRout, as would be the case in the absence of O3, then doubling both IRin and IRout would have a significant warming effect, more than sufficient to compensate for the small reduction of IR radiation from the troposphere in the 15 micron band.
102489. Tom Curtis at 12:17 PM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        Bob Guercio @115: Question: I understand what lapse rate and adiabatic means but what is meant by the adiabatic lapse rate? Is there another kind of lapse rate? The Lapse rate is the change of temperature with change of altitude, and more specifically the lapse rate = -dT/dz. Because convection and latent energy dominate heat transfers in the troposphere, the lapse rate in the troposphere approximates to the the dry adiabatic lapse rate or the moist (or saturated) adiabatic lapse rate depending on relative humidity. At 0% humidity, the adiabatic lapse rate equals the dry adiabiatic lapse rate. At 100% humidity it equals the saturated adiabatic lapse rate. The adiabatic lapse rate is the rate of fall of temperature with increasing altitude predicted by the fall in pressure with altitude, as adjusted by release of latent heat as moisture condenses due to falling temperature. In practise, the environmental lapse rate rarely equals the adiabatic lapse rate because energy release from condensation and energy absorption of sunlight by clouds is rarely gruadual. However, the adiabatic lapse rate dominates only in the troposphere (and possibly mesosphere). At the tropopause, the lapse rate is zero; and in the stratosphere it is negative. It is again zero at the stratopause, positive in the mesosphere, zero at the mesopause, and negative again in the thermosphere. Even if we exclude convection as a means of transfering energy in the atmosphere, and hence exclude the adiabatic lapse rate as a temperature profile, radiative transfer in an optically absorbing atmosphere will generate a lapse rate, indeed, typically a shallower (greater change in temperature for a given change in altitude) lapse rate than the adiabatic lapse rate. Therefore this reasoning should still hold. Question/Comment: To me, shallower means a more gradual or lower lapse rate. Please clarify. Also, less shallow than what? The lapse rate is generated by the radiative transfer of energy so it seems as if you are comparing something to itself. A shallower slope is one with a greater change in the x axis for a given change in the z axis. In this case, the x axis is temperature and the z axis is altitude. In speaking of slope I am speaking of dZ/dX, whereas the lapse rate is measured as - dT/dZ; so I can see how this can cause confusion, for which I apologise. In a grey atmosphere, ie, one which is uniformly absorbing of IR at all wavelengths and has no convective heat transfers, the lapse rate is much greater than that determined by convection, ie, the adiabatic lapse rate. (As the lapse rate is the negative inverse of the slope of the plot of altitude against temperature, that means it has a much smaller slope.) As the IR absorption is restricted to fewer wavelengths, the radiative lapse rate will decrease; but in Earth's atmosphere it is still greater than the adiabatic lapse rate (I believe) although not much greater. I believe it is because of this that at the 60th parralel, the convectivion that drive the polar cell forms. Quesion/Comment: But I think that the portion of the IR spectrum that would be absorbed by the stratosphere has less IR energy in it after going through and being absorbed by the troposphere. It does, or more correctly that portion has less IR energy after being absorbed by CO2 and reradiated at a lower energy level because the CO2 is at a lower temperature. However, most of that energy escapes to space, so it is quite possible for there to be less energy coming from the troposphere in that band of the spectrum, but more energy being absorbed by the stratosphere in that band. It just means that less of the energy from the troposphere escapes to space in that band.
102490. Berényi Péter at 12:10 PM on 4 December 2010
        We're heading into an ice age
        #147 muoncounter at 03:54 AM on 4 December, 2010 Once the ice is fully frozen, why would there be any further aging of the air? How credible are these reported age discrepancies between ice age and air age? It is explained here. Basically it's because ice is cold & accumulation rate is low. Bubbles are enclosed only near the firn-ice transition zone, about 90 m below surface. I am not sure however, that gas diffusion is stopped as soon as bubbles get enclosed. There's a microscopically thin boundary layer between ice grains where impurities get concentrated and supercooled liquid water is retained even at temperatures well below freezing.
102491. actually thoughtful at 12:00 PM on 4 December 2010
        Renewable Baseload Energy
        Bibliovermis -really? What CO2 intensive activities are associated with: solar thermal wind PV wave geothermal ? The ongoing CO2 comes from fuel processing - none of that is required for renewables. I don't know how the concrete/watt metrics come out. If, as I suspect, nuclear has a huge disadvantage here (more concrete per watt than renewables), then there is only CO2+ for nuclear when you compare them. Maybe apples to apple slices.
102492. KR at 11:58 AM on 4 December 2010
        Renewable Baseload Energy
        Bibliovermis - Quite true, all power plants will require concrete, raw material mining, and (except for non-biomass renewables) continuing fuel mining/collection, CO2 emission from the vehicles used, etc. But nuclear is definitely far from carbon neutral. Uranium (especially the fissionable isotopes) is a pretty diffuse fuel, and you have to move a lot of rock to get significant quantities.
102493. Bibliovermis at 11:51 AM on 4 December 2010
        Renewable Baseload Energy
        That's an apples to apple cores comparison unless the same full life cycle analysis is applied to the other electricity generation methods.
102494. Spaceman Spiff at 11:49 AM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        Bob Guercio at 10:52 AM The answer to your first question is "yes". The up and down transition rate equations contain many terms (spontaneous radiative decay, radiative absorption, induced emission, collisional excitation and de-excitation, ....). Collisional excitation followed by radiative decay via a photon that escapes is an important process in the stratosphere. Radiative absorption is not dominant (excepting in the ozone bands and the central CO2 transitions very near to 15 microns). I am not sure I know what you mean by, "The energy in the absorbtive portion of the band has been depleted after going through the troposphere." What you see in the main CO2 band isn't due to Beer-Lambert's law. What you are seeing is largely due to light emerging from the layer at which the optical depth (dimensionless measure of matter's ability to absorb or scatter light) has fallen to ~1 (the "photosphere"). Deeper down, the optical depth is too large (the photon mean free path too small), and most of the light is absorbed (and "re"-emitted) locally. The thermal emission is very sensitive to temperature, in that higher T gas emits more strongly. So where in wavelength the atmosphere is most opaque, the emitting layer (photosphere) lies high up in the troposphere where the T is low and so the thermal emission intensity is also low. Where it is less opaque, it arises from deeper layers in the troposphere where T is higher and thus is the thermal emission intensity. An exception to this is the set of very, very optically thick transitions of CO2 lying very near 15 microns. Here the atmosphere is so opaque (due to the strength/probability of the transition) that this light's effective photosphere lies up in the stratosphere, where T is substantially higher than in the troposphere below (due to O3 dissociation by UV sunlight). The escaping emission there is therefore brighter than in surrounding wavelengths within the surrounding CO2 transitions, and thus the sharp, narrow, reversal you see at 15 microns at the center of the main CO2 "trough". Does that help at all?
102495. actually thoughtful at 11:35 AM on 4 December 2010
        Renewable Baseload Energy
        Money quote from Rob's link: "In the paper "Nuclear Power : the energy balance" by J.W. Storm and P. Smith (2005) download here, the authors calculate that with high quality ores, the CO2 produced by the full nuclear life cycle is about one half to one third of an equivalent sized gas-fired power station. For low quality ores (less than 0.02% of U3O8 per tonne of ore), the CO2 produced by the full nuclear life cycle is EQUAL TO that produced by the equivalent gas-fired power station."
102496. Rob Honeycutt at 11:08 AM on 4 December 2010
        Renewable Baseload Energy
        Here is an interesting take on the CO2 involved in nuclear energy.
102497. Tom Dayton at 11:05 AM on 4 December 2010
        2nd law of thermodynamics contradicts greenhouse theory
        damorbel, I can't get past even your second paragraph, which seems to be gibberish.
102498. Bob Guercio at 10:52 AM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        Spaceman Spiff - 113 Please help me understand. There are many mechanisms that populate the upper level of a radiative transition. One is by absorbing a photon having (virtually) that wavelength. But another possibility is collisional excitation. If the collision rates (gas density) aren't too large relative to the rates of radiative decay, then the collisional excitation has a chance to radiatively decay, rather than redistributing the energy back out into the thermal pool of gas due to a subsequent collisional de-excitation. So the thermal energy of the gas is converted into radiative energy -- and if that radiative energy escapes, this is a net cooling process. This is what is meant by a "net emitter". Questions: I think what you are saying here is that sometimes during a collision, the kinetic energy of motion is lost and reappears as internal energy of a molecule. That molecule then emits radiation. Do I have this correct? The point is that with exception of the CO2 transitions lying near the very strongest ones near 15 microns, the stratosphere is largely transparent to radiation from below (in particular, that which arises in wavebands corresponding to transitions in C02). Run the default model from David Archer's website (70 km, looking down), linked within the OP. See that sharp reversal in the spectrum within the center of the CO2 band? That light is emerging from an effective "photosphere" that lies within the stratosphere. Nearly all of the other light you see in that spectrum, including that within the C02 band is emerging from an effective photosphere somewhere within Earth's troposphere (but in the 800-1200 cm^{-1} spectral region it's emerging mainly from near Earth's surface, excepting the O3 trough near 1050 cm^{-1})-- and passes largely unscathed through the stratosphere. Question: Isn't this kind of what I'm saying. The energy in the absorbtive portion of the band has been depleted after going through the troposphere. To be continued. The stratosphere emits escaping radiation at a rate (that's the cooling rate) that is balanced by the energy deposited via absorption of short wavelength solar radiation by O3 and O2, resulting in molecular dissociation (that's the heating rate). One of the most radiatively active gases in the stratosphere is C02. Increase its abundance, and the cooling rate will exceed the heating rate until a new (lower) equilibrium temperature is reached.
102499. damorbel at 10:35 AM on 4 December 2010
        2nd law of thermodynamics contradicts greenhouse theory
        Re #287 Ned you write:- "... at a particular wavelength. Part of the problem with damorbel's argument here is that the incoming solar radiation has a very different spectral distribution from the outgoing longwave radiation." The wavelenth difference is indeed great but what that count for? Sure it indicates that the Sun/Earth system is in considerable disequilibrium. But the only significance of this is the nature of the disequilibrium, which is precisely what we are talking about, the contradiction of AGW/GHE 'science' and the 2nd Law of thermodynamics, exactly the OP topic of this thread. Further you write:- "Absorptance in the visible/near-IR is not necessarily equal to thermal infrared emissivity. A statement like that just confirms what I am arguing. If they weren't equal there wouldn't be an equilibrium temperature of any sort. If emissivity always was different from 1-a (a is albedo) then the temperature would never be stable, rising or falling according to the sign of the difference.
102500. Bob Guercio at 10:31 AM on 4 December 2010
        Stratospheric Cooling and Tropospheric Warming
        Tom Curtis - 83 Please help me understand. I went only so far so once I understand this I'll continue and probably have more questions. Thank you, Bob After carefull consideration, I believe the explanation of stratospheric cooling given in the original post is simply wrong. To see this, consider a hypothetical planet whose atmosphere is completely transparent at all wavelengths of electromagnetic radiation. In this case, its surface temperature will be its temperature as measured from space, ie, its effective temperature. The temperature at any point in the atmosphere above the surface will be less than the effective temperature, and the temperature profile of the atmosphere will be defined by the adiabatic lapse rate up to the thermosphere. (Like Venus, see graphic in 80 above, it will have no stratosphere.) Question: I understand what lapse rate and adiabatic means but what is meant by the adiabatic lapse rate? Is there another kind of lapse rate? Now, as we introduce CO2 into the atmosphere, what happens is that the altitude of the effective temperature gradually increases in height. As the temperature profile is still defined by the lapse rate, the temperatures at every altitude up to the thermosphere will also increase. Question/Comment: Yes. CO2 absorbs IR in accordance with the greenhouse effect. Even if we exclude convection as a means of transfering energy in the atmosphere, and hence exclude the adiabatic lapse rate as a temperature profile, radiative transfer in an optically absorbing atmosphere will generate a lapse rate, indeed, typically a shallower (greater change in temperature for a given change in altitude) lapse rate than the adiabatic lapse rate. Therefore this reasoning should still hold. Question/Comment: To me, shallower means a more gradual or lower lapse rate. Please clarify. Also, less shallow than what? The lapse rate is generated by the radiative transfer of energy so it seems as if you are comparing something to itself. Looked at differently, and using Earth as our model, we need to consider that the effective altitude of radiation, ie, the average altitude from which radiation reaches space, lies several kilometers below the tropopause. Therefore most outgoing radiation at the tropopause reaches space, and the Beer-Lambert law is an appropriate approximation of the effect of changing CO2 concentrations in the stratosphere. Given that, then if we double the CO2 concentration we also double the amount of IR radiation absorbed by CO2 in the stratosphere. The amount of IR radiation outgoing from the tropopause will not itself double, but infact will slightly fall because the atmosphere is optically thick below the tropopause. Consequently, although the net radiation entering the stratosphere will fall in this scenario, the amount absorbed in the stratosphere will increase. Quesion/Comment: But I think that the portion of the IR spectrum that would be absorbed by the stratosphere has less IR energy in it after going through and being absorbed by the troposphere. Comment: To be continued. Of course, the amount of IR radiation emitted at a given temperature will also double with doubling of CO2 in the stratosphere. The result is that, if the temperature of the stratospheric CO2 is less than the brightness temperature radiation emitted by CO2 in the troposphere, it will warm. If it is greater it will cool. Of course, had the temperature in the stratosphere followed the adiabatic lapse rate, it would have been less than that of the troposphere; and increasing CO2 would warm the stratosphere, all else being equal. But all else is not equal - the stratosphere is much hotter than the upper levels of the tropospere because of the absorption of UV radiation by ozone. Therefore, I would have to conclude that stratospheric cooling with increased CO2 is primarilly due to increased efficiency at radiating away energy absorbed by ozone due to increased concentration of CO2. There would be a small additional boost due to reduced outgoing radiation of IR in the 15 micron (CO2) band; but that is ony a secondary cooling effect, and would have been a warming effect where it not for the presence of ozone in the stratosphere. Having said all that, I now hope some one will knock some holes in my reasoning.

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