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Jose_X at 04:48 AM on 1 March 2012Radiative Balance, Feedback, and Runaway Warming
Tom Curtis #57, I see IanC spotted a mistake, and I have not read the whole article; however, this remark they made would make me very suspicious that they would decide to use this Tgb value: > Since in accordance with Hölder’s inequality Tgb ≪ Te (Tgb =154.3K ), GHE becomes much larger than presently estimated. > According to Eq. (2), our atmosphere boosts Earth’s surface temperature not by 18K—33K as currently assumed, but by 133K! This raises the question: Can a handful of trace gases which amount to less than 0.5% of atmospheric mass trap enough radiant heat to cause such a huge thermal enhancement at the surface? Thermodynamics tells us that this not possible. We know that this Tgb is very low compared to observations of T, so I take this as a rejection of the modified 1 shell model rather than as a way for the authors to introduce a model that they believe does justify 133K. I'll try to finish reading soon. @Everyone: I wanted to ask people here what they think about this: http://theendofthemystery.blogspot.com/2010/11/venus-no-greenhouse-effect.html . Skimming should give an idea of the main claim. A summary might be that the top section of Venus' atmosphere (50km altitude and up, where the pressures exist on Earth) matches the Earth's atmosphere in temperature once we factor in the ratio of the Stefan Boltzmann calculation for Venus to that of Earth (ignoring albedo!). Although I have been critical of it without passing an official final judgement (note how Venus has similar mass, radius, and hence gravitational constant as Earth), it seems to cast some doubt to what all of that CO2 is doing. Note, the albedo is entirely ignored by Huffman (and this appears to present conservation of energy issues or information traveling faster than speed of light so that emitter A can generate extra radiation beyond S-B to match what B will reflect, etc.. but maybe not (I won't detail guesses I have)). Note that the values used for Venus might be a little off. I found what looked like an authoritative source (need to hunt down the link). While the numbers are a little off from what I saw, they are in the right ballpark (but the deviation is a bit greater). I can imagine that the lapse rate changes shape deeper into Venus, but I think data suggests it is close to a line of similar slope to that of the earth (?). It's also true that right below the top 1 atm isn't a body of water and earth but instead just more air so it is not the same scenario as Earth. A question that follows would be, if the atmosphere was largely N2, would this same general lapse rate exist down to the ground, possibly with only a little bit different slope? Also, would the slope be significantly different or would the rate be a different very distinct curve? Anyway, my main problem is that I don't yet know clearly the equations/algorithm that predict GHE (eg, Ramanathan and Coakley '78), so I can't carry out a few quick checks. If all there was to average temperature was the pressure, we would not experience large oscillations. I don't know what level of variation (eg, deviations from solar tracking.. as CO2 on earth is predicted to be causing for decades now) would be consistent with such a view. There is too much data I have not seen/analyzed and too much theory I still haven't covered. Obviously, I can consider that maybe there are some mistakes in our current understanding of GHE. Or, I can consider that a strong GHE effect leads to 1%-10% or other maximum variations near the surface (a limit I did not think existed). This would bound the earth temperature above (against GHE predictions I think), if still allowing great threat to humans. Anyway, I assumed the WUWT paper being discussed was related to what the Huffman webpage shows. Assuming it is, I don't worry too much about astral rocks with light atmospheres (our high altitude low pressure atmosphere deviates from the lapse rate), but moon Titan might be another example following the Earth/Venus ratio. Any opinions? -
Composer99 at 04:47 AM on 1 March 2012Climate Sensitivity: Feedbacks Anyone?
Now that we're on a (hopefully topical) thread, Matthew L, I'll take a crack at answering. I'm not one of the professionals participating here, so I may well have some major or minor details incorrect. As you state, correctly, positive feedbacks will amplify both warming and cooling forcings in the climate. This is what allows the otherwise weak Milankovitch cycles, for example, to cause climate to shift between glacial and interglacial periods during the current Ice Age. At the time scales you are thinking of, 1-2 years (to say nothing of shorter time scales), the noise in the system (seasonal & diurnal variability, large-scale energy-shifting oscillations such as ENSO, and the like) will tend to either dampen or amplify the forcings & feedbacks in play. So, for example, in terms of surface temps 1998 was aberrantly warm compared to the rest of the 1990s (despite their being, at the time, the warmest decade on record) because of the very strong El Nino, which made the warming seem much stronger. Likewise the recent La Nina phase has dampened the warming of the 2000s and early 2010s. In addition, multiple forcings are at play, some warming (e.g. greenhouse gases, shrinking ice albedo) and some cooling (e.g. solar activity until very recently, aerosols) so contradictory forcings will have contradictory positive feedbacks. Hopefully that helps! -
KR at 04:42 AM on 1 March 2012Climate Sensitivity: Feedbacks Anyone?
Matthew L - Quite correct, a 'positive' feedback amplifies the climate response to forcing changes whether positive or negative. Note that the 'loop' for feedbacks is a diminishing one (gain <1), meaning that there is no "runaway" affect in either warming or cooling directions - just a rather larger movement than one would expect with a forcing change an no feedback. Also keep in mind that feedbacks have time constants to their forcing response - water vapor responds in a matter of days, vegetation in years, ice in years/decades, and ocean temperature/CO2 solubility (to name a few) in centuries. Short term (weather) changes, including the yearly cycle, simply don't last long enough for the longer term feedbacks to take effect - they get averaged out. -
dana1981 at 04:31 AM on 1 March 2012The Independence of Global Warming on Residence Time of CO2
CBD - Dikran corresponded with Essenhigh, who he says didn't really budge, and eventually said something along the lines of "one of us is wrong." He did not raise any valid objections to Dikran's response. -
Volker Doormann at 04:25 AM on 1 March 2012Scafetta's Widget Problems
“Since Scafetta's hypothesized astronomical cycles have no impact on the long-term warming trend, his prediction that future global warming will be minimal is based entirely on his interpretation of the scientific literature. For example, he twice mentions that galactic cosmic rays may play a significant role in influencing global temperatures, but fails to mention any of the dozens of papers which have found little if any correlation between cosmic rays and cloud cover on Earth. Scafetta also fails to mention that solar magnetic field, which influences the amount of cosmic rays reaching Earth, has no long-term trend over the past ~60 years, nor does cosmic ray flux on Earth. Thus how can cosmic rays possibly explain the rapid warming over that period? This question remains unanswered.” Agree. But there are real astronomical cycles – I prefer the dimension frequency [1/sec] or [1/y] – called heliocentric synodic tide functions, which have correlations with some terrestrial data. Solar tide function of Mercury/Earth is phase coherent with the measured sea level oscillation but also visible in the global temperature data from UAH. http://www.volker-doormann.org/images/sealevel_vs_xyzo.gif Solar tide functions of some two or three objects in the solar system are in coincidence with the reconstructed TSI anomaly after F. Steinhilber, et al. over 5 ky: http://www.volker-doormann.org/images/ghi_vs_tsi_6ky.gif Because the solar tide functions easy can be calculated from NASA ephemerides 1000 years ahead daily, a prediction of the global climate with a resolution of month is now possible. V. -
CBDunkerson at 04:22 AM on 1 March 2012The Independence of Global Warming on Residence Time of CO2
Nice to see Energy & Fuels letting you publish an answer to the original paper. Did professor Essenhigh, or any of the others who looked it over, suggest any potential flaws or limitations in your logic? I recall that 'skeptics' refuting it on earlier threads tended to mysteriously vanish when challenged to walk through it step by step and point out any flaws, but I'm wondering if more knowledgeable reviewers had any caveats. -
Doc Snow at 04:18 AM on 1 March 2012The Independence of Global Warming on Residence Time of CO2
I'd like to second that motion! -
Matthew L at 04:17 AM on 1 March 2012Climate Sensitivity: Feedbacks Anyone?
It was recommended I post here from another article. I have a question regarding climate sensitivity (or feedback) where there has been a fall in temperature rather than a rise. As stated in the above article, positive feedback would indicate that the climate warms in response to a warming - presumably in a declining loop otherwise it would be runaway warming. Conversely positive feedback would indicate that the climate cools in response to a cooling - again also in a declining loop. If these positive feedbacks acted quickly in the short-term (1-2 years) would we not see wild swings in the climate from hot to cold? For instance the warm year of 1998 would have led to an even warmer 1999. Likewise the cool 2009 would have led to even colder 2010. I can see positive feedbacks working on longer timescales as evidenced by the transition over a few hundreds of years into and out of ice ages. But from a layman's viewpoint it looks like, if anything, negative feedbacks prevail over the 1-2 year timescale as warm years are followed by cool ones and vice versa. I presume I must be missing something! -
barry at 04:02 AM on 1 March 2012Mythbusting with fewer explosions
Lloyd, the following may be useful for reference, from ultra technical to blogerrific. Ramanathan and Coakley (1978) is a seminal paper, highly detailed and comprehensive, on trace gases and the greenhouse effect. (The models referred to in the paper are numerical representations of radiative transfer in the atmosphere, not GCMs) Ramanathan's 1997 lecture is a slightly(!) less technical explanation of the greenhouse effect, including the role of water vapour. http://www-ramanathan.ucsd.edu/files/pr72.pdf Chris Colose usually does a great job of framing scientific understanding for laypeople. http://chriscolose.wordpress.com/2010/08/23/climate-feedbacks-part-1/ -
Composer99 at 04:02 AM on 1 March 2012The Independence of Global Warming on Residence Time of CO2
Congrats to Dikran on the publication! -
IanC at 03:46 AM on 1 March 2012Radiative Balance, Feedback, and Runaway Warming
Reading Nikolov and Zeller's second article on WUWT cracks me up. They kept on insisting that their answer must the right one, so if the observation differs from their answer they should just use their calculated answer to as the observation. The real gem is the following:In a recent analytical study, Smith (2008) argued that Eq. (5) [refers to N&K's grey body model] only describes the mean temperature of a non-rotating planet and that, if axial rotation and thermal capacity of the surface are explicitly accounted for, the average temperature of an airless planet would approach the effective emission temperature. It is beyond the scope of the current article to mathematically prove the fallacy of this argument. However, we will point out that increasing the mean equilibrium temperature of a physical body always requires a net input of extra energy. Adding axial rotation to a stationary planet residing in a vacuum, where there is no friction with the external environment does not provide any additional heat energy to the planet surface. Faster rotation and/or higher thermal inertia of the ground would only facilitate a more efficient spatial distribution of the absorbed solar energy, thus increasing the uniformity of the resulting temperature field across the planet surface, but could not affect the average surface temperature. Hence, Eq. (6) correctly describe (within the assumption of albedo uniformity) the global mean temperature of any airless planet, be it rotating or non-rotating.
Again, they would just assert that their model is correct. They are unable to mathematically prove Smith 2008 to be wrong because Smith 2008 is correct: rotation and heat capacity do matter, and N&K's solution is merely a special limit, obtained by taking rotation speed to infinity or heat capacity to zero. It is particularly ironic because N&K repeatedly invoked Holder's inequality, and argue that one must be careful when integrating a non-linear quantity. If they really were this careful, they would realize that calculating the average surface temperature of a spherical object is inherently non-linear, so increasing the uniformity of temperature will certainly change the answer. I know that Smith2008 has been mentioned here on SkS in a post on Postma, but are there plans for a detailed explanation of the Smith 2008? Also, given that N&K's theory is starting to appear, is there a rebuttal planned? -
Mike at 03:14 AM on 1 March 2012Mythbusting with fewer explosions
"It's not enough to merely remove the myth. When you debunk misinformation, you leave a gap in the person's understanding. That gap needs to be filled with an alternative explanation." I have read similar things in articles on math education. It is not enough to show a student why their misconception is wrong. You have to replace it with the correct concept. For example students often think (a+b)^2 = a^2 + b^2. In explaining why this is false I draw the picture so they can see the missing pieces. But here is something else. On a test they will revert back to the misconception. The stress causes their minds to flip back to their misconception. You might think about if that applies the more general myth busting. The economic down turn was/is a huge stressor. -
Hyperactive Hydrologist at 03:03 AM on 1 March 2012New research from last week 8/2012
What about a combination of both linear and step changes? For me this makes the most sense especially when applied to rainfall and considering atmospheric teleconnections such ENSO and the NAO. -
Tom Curtis at 02:33 AM on 1 March 2012Radiative Balance, Feedback, and Runaway Warming
IanC @60, you are correct. Thankyou for taking the trouble of checking. -
IanC at 02:06 AM on 1 March 2012Radiative Balance, Feedback, and Runaway Warming
Jose_X 56, Yes of course, I meant pressure driven by temperature. Thanks for pointing out the mistake. (Mods: is there a way to fix the error in my post in 51?) Can you elaborate your question? Are you talking about the substance in gas phase? or in solid or liquid phase? Tom Curtis 57, I think you made a mistake after step (d). For (e) i got 0.9797, and from here I have (f) (1-A)/e = 0.912 (g) A=0.125 (h) 1/e=1.0423 ==> e= 0.9594 -
Tom Curtis at 02:00 AM on 1 March 2012Radiative Balance, Feedback, and Runaway Warming
Riccardo @58, it partially makes sense for a no-atmosphere, local equilibrium case. As calculated, Tgb assumes no thermal inertia, and no thermal distritution through conduction (or any other means). That is as unrealistic an ideal case as the standard "effective temperature", which in effect assumes absorptivity of 1, and perfect heat distribution so that no point on the surface has a different temperature than any other point. The practical importance of the effective temperature is that it is a maximum mean surface temperature that can be achieved without a green house effect. Conversely, Tgb calculates a theoretical minimum temperature for a body without an atmosphere. As such it is very surprising that Nikolov and Zeller report an observed mean surface temperature for the moon equal to their calculated mean surface temperature, ie, 154.3 K (table 1). Pressed to justify this figure on WUWT, Nikolov justifies the value by appeal to Vasavada et al, 1999 who report modelled mean lunar surface temperatures of 220 K at the equator (figure 3), and 130 K at 85 degrees north (figure 4) (also reported by wikipedia). Calculating the mean as (140 plus 140 plus 220)/3, yields a mean surface temperature of 167 K, which is probably an underestimate. Nikolov also appeals to Diviner, which reports a mean equatorial temperature of 206 K, and a mean polar temperature of 98 K (mean of equator plus two poles: 134 K, but the averaging method leaves much to be desired) Nikolov himself calculates the mean form the diviner data as (100+206)/2 or 153 K. These very low values contradict the subsurface measurements at the Apollo 15 (26 degrees North) and Apollo 17 (20 degrees North) sites. They show a subsurface temperatures approaching 253 K (Apollo 15) and 257 K (Apollo 17) conservatively estimated, showing these temperatures to be the mean surface temperature for those sites, ie, in a sub-equatorial region the mean temperature is at least 30 degrees K higher than estimated by the model, and nearly 50 K higher than estimated by Diviner.
Consistent with that, Daniel Harris cites Peter Eckart ("The Lunar Base Handbook", 2nd Ed 2006) to the effect that the polar region (excluding shaded craters) has a mean of 220 K, while equatorial regions have a mean of 255K. (Rough estimate of the combined mean: 230 K).
I have also seen figures of 243 K and 250 K cited with dubious provenance. I have been unable to find relevant figures from the Chang E-1 satellite
The important thing about this is that while Nikolov and Zeller report an observed mean surface temperature of the moon as being 154.3 degrees C, clearly the observation made in determining that value was that that was what their theory predicted. In some circles reporting theoretical predictions as being observed results is frowned upon. That Nikolov and Zeller are prepared to do so, however, calls into question the remarkable "predictive accuracy" of their theory as shown in their figure 5. It may well be that for many values, and not just for the Moon, what is "accurately predicted" is just the value calculated in the prediction.
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Composer99 at 00:43 AM on 1 March 2012Satellites find over 500 billion tons of land ice melting worldwide every year, headlines focus on Himalayas
Matthew L: I suspect an ideal approach is to seach for a thread relating specifically to sensitivity or feedbacks using the search feature at the upper left of each page on this site. For example, such a search led me to this page which is probably ideal for your purposes. Or the main page has 'newcomers: start here' and 'the big picture' links to their respective pages, which are probably good places to post such queries. Me not being part of the site team, though, you might take this particular suggestion with a grain of salt. -
Climate-Change-Theory at 23:55 PM on 29 February 2012David Evans' Understanding of the Climate Goes Cold
Tom @ #45 My response was very much on topic because ... The very first section of this article is about climate sensitivity and it discusses the assumed feedback of water vapour which is supposed to reduce carbon dioxide's effect to 1.2 out of 3.0 (which I calculate as 40%, though the author of this article calculates as "one-third") So I was explaining why water vapour does not have such an effect because (a) it sends some of the solar IR radiation it captures back to space, thus cooling and (b) the backradiation it (and carbon dioxide) quite correctly do create is actually only all standing waves which cannot transfer any energy to the surface, but can slow radiative losses, even though diffusion and evaporation then compensate.Response:[DB] "My response was very much on topic because ..."
Incorrect. The topic of the thread was about David Evans' Understanding of the Climate Goes Cold. As is your wont in this forum, you then proceeded to make this about your misunderstandings of physics and climate and not about the topic of the thread.
You then compound things by threatening to smear SkS on other venues. That is reflective of both you and the nature of those venues that will tolerate that type of posting.
As this is a pattern of behaviour of long standing with you, you are no longer welcome here.
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Riccardo at 23:46 PM on 29 February 2012Radiative Balance, Feedback, and Runaway Warming
Tgb is not part of the one layer model, it's just a new definition of the gray body temperature. It assumes a temperature distribution proportional to the cosine of latitude to the 1/4 which gives a temperature at the poles of zero Kelvin and of about 360 K at the equator (for the Earth). This makes sense in the no-atmosphere, local equilibrium, case like the Moon. Given this definition, though, Tgb can not be compared to the effective radiating temperature to quantify the greenhouse effect. -
Tom Curtis at 23:32 PM on 29 February 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
dunc461 @25, around 295 K (23 degrees C) is a reasonable estimate of the surface temperature based on the Conrath data. Of course, the Earth's Mean Global Surface Temperature is about 288 K (15 C), however, that is the mean temperature, not the temperature at any given location. The observations in this case were made over the Gulf of Mexico near Brownesville, Texas, so a surface temperature around 23 C is hardly surprising. -
Matthew L at 23:10 PM on 29 February 2012Satellites find over 500 billion tons of land ice melting worldwide every year, headlines focus on Himalayas
Rob Painting #90. Thanks for the heads up on the paper by Carmen Boening that is due. I will keep an eye out for it. Unlike Camburn I don't doubt that sea level and OHC continue to rise, but it is clear that the rate of rise has slowed in both cases over the last 5 or so years. I have argued with fake-sceptics elsewhere who deny that the Earth is warming that the rise in sea levels is evidence that it is, in other words that the sea acts like a giant thermometer. Obviously things are much more complex than that but the depth of ignorance out there is staggering. Brilliant site by the way! We really need somewhere that deals with facts and real science rather than ill-informed speculation. I am new to posting here (been a lurker for a little while) and have a query on sensitivity / positive feedback (is cooling amplified as well as warming?). Is there a general thread / forum where I can post such questions? pps - Still extremely irritated by the use of such an old fashioned map projection in Figure 1. It does nobody any favours and could be read as a deliberate effort to mislead (obviously not your fault of course). There are plenty of much more informative alternative projections available so there is no excuse. Presenting information in maps and plans is a big part of my job, so I am very aware of how misleading and "political" maps can be! -
SRJ at 22:46 PM on 29 February 2012Empirical evidence for positive feedback
I would suggest that this page is updated with the newest research in this topic. -
dunc461 at 21:45 PM on 29 February 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
These may be a dumb questions but on the Conrath Graph, at 975 cm^-1,interpolation between 280K and 300K give a temperature of 294.5K. Isn't this significantly higher than the measured temperature at the earth surface? And couldn't it signify that some of the absorbed radiation is emitted at this wave number? -
Dikran Marsupial at 21:39 PM on 29 February 2012Newcomers, Start Here
PRussel 1. Calling someone a sceptic is actually a complement, we all ought to be sceptics in the sense that we take nobody's word for anything and investigate the evidence behind all claims. I agree, namecalling does not help anybody, but if those on the other side of the debate are not to be called sceptics, how should we refer to them? What term would you use to describe those who hold the contrary view, but who are not swayed by evidence or rational argument? If there were more neutral terms that everybody were happy with them, I'd happily use them instead (I see nothing wrong with "sceptic" BTW). 2. The main purpose of SkS is to provide the counter arguments to climate myths, these appear to be almost exclusively from the contrarian scientists for a good reason. For every Gallileo, who runs against the mainstream position, there will be literally thousands of scientists who are simply mistaken. This is true in all branches of science, the only difference is that in other sciences they don't generally get any media coverage. 3. If you can't imagine any scientist applying for grant money to research a theory that humans are not to blame, then read Svensmark and Calders book "the chilling stars", where Svensmark complains about the lack of funding he has recieved, but if you actually total up the amount of grants that he mentions in the book, he is actually pretty well funded (better than I am!). Likewise look up Jasper Kirkby and the CLOUD project at CERN, which was funded to the tune of 12,000,000 Euro, in this very political climate. Note also that Roy Spencer (leading sceptic scientist) says that his work is 100% govenment funded. There are plenty of complains that sceptic science isn't funded, but that doesn't mean it is true, it is more likely that the proposals simply have too many holes in them to be funded above better proposals that are more coherent. -
jatufin at 21:13 PM on 29 February 2012Newcomers, Start Here
PRussell @184: 1. Name calling is rarely appropriate, and should be avoided however heated the discussion is. But if you look at "skeptical" web sites, or even listen public "skeptical" figures on TV, you often encounter nice terms like: "warmists", "alarmists", "conspirators" and "climate nazis", with unwarranted accusations of fraud, incompetence and child-molestation. This has of course nothing to do with science. 2. You have your 3% There is no consensus I suppose there is percentage of geologists, who deny plate tectonics and astrophysicists backing continuous creation cosmology. 3. Cui bono? I have a gut feeling, that succesfull "skeptical" talking head without any credentials might earn substantially better than real scientists in the field. (many of whom could easily find hugely more profitable jobs in mineral industry, than in academia) -
les at 20:44 PM on 29 February 2012Newcomers, Start Here
184 - PRussell Re your points 2 & 3. regarding "contrary viewpoint" and "grant money to research a theory that humans are not to blame"... These points are, I think, quite common. I would suggest you consider this: If you look at 99% (as in 99% of all statistics are made up on the spot) of research papers, you'll find they're either just measuring stuff or comparing theories with data. The vast majority are not in the least bit concerned with proving or disproving any grand thing. Example, if you read the new Mann book, he points out - and this is known - that his PhD research was on 'oscillations' in climate and he only looked at forcing as a side issue to make his analysis complete... and as a side issue, the original 'hockey-stick' just "popped out" (and it, or all the independently analysed variations of it are not myths). The papers which 'prove AGW' are largely calculations of attribution (what role is played by the sun, atmosphere, oscillations etc etc) - there's no "prove" or "disprove" about most of them either - it's just a question of how the system works. Outside the blogosphere, there really isn't that much difference between the scientific beliefs about how the climate works except for a question of degree (e.g. feedback's) and emphasis. -
PRussell at 20:25 PM on 29 February 2012Newcomers, Start Here
Your site is very interesting and your debunking the myths gives me cause to think - what is it that makes me sceptical? I agree that I am not an expert, so why do I have doubts? Not only are your backfire effects pertinent to me but I have come up with a few more backfire effects that also affect me. 1. I get really turned off by the name calling - when scientists start calling people sceptics and deniers and try to belittle anyone with an alternative view I find that reinforces my sceptical view. As an example on your web site anything that is against your theory you label as a myth to be totally discredited. That labels me a sceptical denier who believes in myths. I thought I just had a few doubts and would like to hear both sides. 2. Another backfire effect for me is the incredibly strong bias that there is only one valid opinion – do we have scientific fact? I find it hard to believe that with the enormous amount of research that is going on that every single theory that every single scientist has, supports global warming. Surely there must be some evidence of a contrary viewpoint. For me your arguments would be more powerful if you had listed the hockey stick graph in your list of myths to demonstrate your even handling of the facts. 3. And my final backfire effect is the money. Maybe it is jealousy but I see people like Ross Garnaut making lots of money out of this theory. I can’t imagine any scientist applying for grant money to research a theory that humans are not to blame. Realistically the grant will not be approved because of our political climate. -
Tom Curtis at 19:58 PM on 29 February 2012Radiative Balance, Feedback, and Runaway Warming
Jose_X @55, I see what you are saying, but equation (7), which is definitely part of the new theory explicitly includes the therm Tgb. What is more, their figure 5 plots the ratio of Ts to Tgb. Hence Tgb is definitely part of the new theory. The only definition they provide for it, however, is in equation (2) and related discussion. Therefore, that is not a flaw in my algebra. It is at best a flaw in their presentation, such that they do not have a theory until they provide us with an alternative definition of Tgb, assuming, of course, no other error in my algebra. -
Doug Hutcheson at 19:57 PM on 29 February 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
owl905 @ 23, Thanks for the link, it has cleared up some of my confusion. Much clearer now. Fascinating subject, with all its twists and turns. -
Lloyd Flack at 19:17 PM on 29 February 2012Mythbusting with fewer explosions
John, I was thinking about those graphs that you show showing changes in the spectra radiated into space and re-radiated back to Earth that show the changes due to CO2 Changes. Has the effect of water vapour also been done? I ask this because you have denialists who say that they concede the effect of CO2 but they dispute the water vapour increase. But the effects of non precipitating greenhouse gases combined with those of water vapour together put the sensitivity most of the way to the usual estimate of the Charney sensitivity. You do not need a large cloud effect to get the usual estimate. You would need a large negative cloud effect to get a low sensitivity. It puts them on the spot.Response: [JC] The graph I showed comes from Harries et al 2001 and takes the water vapor effect into account. There's a link to the full paper including graphs including the water vapor effect at http://sks.to/greenhouse -
Doug Hutcheson at 19:16 PM on 29 February 2012Global Extinction: Gradual Doom as Bad as Abrupt
If we are talking of Gradual Doom (or Abrupt, for that matter), it would be a mildly interesting mental exercise to come up with a means of storing our accumulated knowledge in such a way that it would be available for the next sentient race to evolve on Earth. It would have to survive global catastrophes like volcanoes and earthquakes, perhaps even meteor strikes. It would have to provide a full training manual, to explain how to access the information it stores. That would mean it would require a 'bootstrap' section explaining our language and sufficient physics to enable the discoverer to apply the correct kind of power to the correct terminals of the box. Something like the discs in H. G. Wells' "The Time Machine" might do it. But then, who would want the knowledge acquired by a race that learned how to destroy a perfectly satisfactory biosphere? -
Jose_X at 18:53 PM on 29 February 2012Radiative Balance, Feedback, and Runaway Warming
Chris Colose, if there is some value to the idea that pressure of the atmosphere (assuming it has some amount of ghg) is intimately linked to lapse rate and temperature, observations on earth at our human life timescale do appear to show strong correlations between unpredictable and human changes to the atmosphere and results in temperature. These drivers cannot be called natural cycles. In fact, even natural cycles, as long as they are not driven by the sun, would appear to contradict any such theories. There at least would be a strong argument that the best descriptions of short-term changes have been captured in climate models. A steady state over millions of years perhaps is immaterial to the main question over our fate. -
Jose_X at 18:43 PM on 29 February 2012Radiative Balance, Feedback, and Runaway Warming
Tom Curtis, I think the problem is at step b because eqn 2 forms part of a criticism of the 1 shell model, and I don't think it goes with section 3, where a new theory is covered. @IanC >> Their argument that temperature is driven by pressure is just pure non-sense. There is nothing in their argument that prevents me from arguing that temperature is driven by pressured. I think you meant that we could argue the converse, that pressure is driven by temperature. What do we know about restraints on volume (or concentration of particles)? I had seen a wikipedia reference (that I can't find this second) relating adiabatic polynomial adiabatic 7/2 power to degrees of freedom polynomial 5/2 power to predict some natural balance in volume increases ... ??? -
owl905 at 18:33 PM on 29 February 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
@Doug 21 - decent summary, same page as you. The balance is restored after the change in GHG's levels out ('in the pipe' lag). In a picture of the heat balance, allow for absorption by land and water. Another fly in the ointment is the cooling effect from upper atmosphere ozone (the CFC issue). fyi: This looks like a decent synopsis site: Global Warming: Man or Myth -
Tom Curtis at 17:54 PM on 29 February 2012Radiative Balance, Feedback, and Runaway Warming
Looking at the "Unified Theory of Climate", I notice form equation (7), you have that: NTEPs = Ts/Tgb Substituting into equation (8), we obtain: Ts = 25.3966(S0 + 0.0001325) 0.25 * Ts/Tgb Dividing both sides by Ts/Tgb, we have (a) Tgb = Ts = 25.3966(S0 + 0.0001325) 0.25 Substituting from equation (2), we then have (b) 2/5 * {(S0 + 0.0001325) * (1 - Agb)/(es)}0.25 = 25.3966(S0 + 0.0001325) 0.25 where A stands for albedo (alpha), e stands for emissivity (epsilon), and s stands for the Stefan-Boltzmann constant (sigma). Hence we have: (c) [{(S0 + 0.0001325) * (1 - Agb)/(es)}0.25]/(S0 + 0.0001325) 0.25 = 63.4915 Cancelling out and distributing, we have (d) (1 - Agb)0.25/(e0.25*s0.25) = 63.4915 and hence (e) (1 - Agb)0.25/e0.25 =~= 0.8239 or, by raising both sides to the fourth power: (f) (1-Agb)/e =~= 0.4607 We are told that (g) Agb =~= 0.125, and hence (h) 1/e =~= 0.5265 or (i) emissivity approximately equals 1.9 which is impossible. OK, maths is not my strong suite, so it is entirely possible I have made an algebraic error above. If so, could somebody please point it out to me. But if not, why are we paying attention to this ridiculous theory which can be true only of the laws of thermodynamics are false. -
Glenn Tamblyn at 17:31 PM on 29 February 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
Boba10960 and others "There were comments at this site some time ago (too long for me to find them now) that led me to believe that increasing the CO2 content of the atmosphere raises the average altitude from which IR radiation escaped to space. Ever since that time I have wondered how that works (if true), and your post has stimulated me to ask." Yes, when you add more CO2 the average altitude at which IR is able to escape to space does increase. But it is more complicated (and more interesting) than that. Whether IR can escape to space requires that the amount of GH gases above it is low enough that the probability of it being absorbed by those molecules drops to something significantly below 100% And this probability depends on 2 things. How many GH molecules are between the IR photon and Space and the probability that the GH molecule will absorb it if they happen to interact. No GH molecule will automatically absorb an IR photon that passes close enough to it. There is a certain probability that it will. And this probability isn't constant across the entire frequency range that a GH molecule can absorb at. It is more likely at some frequencies than others. So the altitude at which escape to space is possible varies with frequency. At frequency f1, the probability of a CO2 molecule absorbing a photon at frequncy f1 mght be X. At frequency f2, if CO2's probability of absorbing at f2 is X/2, then there need to be twice as many CO2 molecules available to give the same effective probability of absorption. So the altitude at which f2 photons have a clear path to space is lower than the altitude for f1 photons. And this behaviour is clearly visible in the graph's Tom has put up. But to understand this we need some extra information. What the temperature profile of the atmosphere is like. As we rise from the ground, air temps drop by around 6.f DegC / km. This keeps happening for between 11-17 kilometers, depending on what latitude you are at. Then as you go higher temperatures don't drop any further. This point is called the Tropopause and is the dividing point between the Troposphere and the Stratosphere. Then as you go higher into the Stratosphere temperatues don't change for quite some period. Then in the upper Stratosphere temps actually start to warm again. And we can see exactly this in the Graph. CO2 has a distribution of absorption probabilities that is highest at the centre of the notch and declines fairly linearly as we move to frequencies on either side. Notice the spike at the centre of the CO2 notch. This is the frequency where CO2 is most likely to absorb. It is so likely that the altitude at which the path to space for that central frequency is in the upper stratosphere where temps are somewhat warmer. Then as we run our eye slowly to the left from that central spike the intensity drops. That is us moving down through the upper Stratosphere and temps are getting colder. Then the spike reaches the 220K line on the graph and roughly stays there as we keep moving out. At this point our decrease in altitude has taken us into the lower Stratosphere where temperatures don't change evean as our clear to space altitude keeps dropping. Finally as we move further out the IR line starts to climb again, to warmer values. Now we are descending even lower, below the Stratosphere into the Troposphere and we are seeing it's temperature profile as we descend further. Eventually, the CO2 notch meets the region on the left that is all 'ragged'. This is H2O absorption lower in the Troposphere. This doesn't mean that CO2 still plays no part. Rather its probability of absorption is now so low, its clear to space altitude is so low, that even if an IR photon could get past all the CO2 molecules, the probabilty of being absorbed by H2O molecules means they still can't escape. So here H2O's behaviour dominates. If you keep coming back from time to time, I intend to put a post up here at SkS sometime in the next 2 weeks that will go into all this in some detail, including graphics that will make it a lot easier to understand than just words. -
Chris Colose at 17:20 PM on 29 February 2012Radiative Balance, Feedback, and Runaway Warming
galloping- You are free to believe pseudoscience. I couldn't care less, nor does it have the slightest impact on the progress in scientific literature. -
Jose_X at 16:59 PM on 29 February 2012Radiative Balance, Feedback, and Runaway Warming
gallopingcamel, 3: So if you read point 2, you know that I am definitely open (based on my limited experience solving equations of the atmosphere) to the idea that the greenhouse effect may be neutered in general.. at least in the long run. However, all the planets and astral rocks considered (and I haven't read the main part of the article/paper yet, but have seen discussions related to observed patterns of natural pressure/temperature linkages in the atmosphere) have not been impacted by man. There is no direct evidence from other planets of what can or can't happen under a scenario just like the one we have on earth. These rocks in space don't have huge bodies of water, for example. And, they also don't support diverse lifeforms. Driving the planet beyond the natural range, at some point, can definitely lead to harm to (human beneficial) organisms (including humans) at a wide scale. In other words, we need something more quantifiable and germane to our current planet and the times scales key to our survival and well-being. -
IanC at 16:42 PM on 29 February 2012Radiative Balance, Feedback, and Runaway Warming
gallopingcamel, Just because there are thermodynamics equations in Nikolov & Zeller does not mean that they have been applied properly. N&K first argues that the usual simple radiative balance model (which by the way is valid for a rapidly rotating planet with large heat capacity) is bad, and then proceeds to apply an even worse model (i.e. one that is valid for a slowly rotating planet with low heat capacity) to argue that the greenhouse effect can't explain the large temperature difference; in reality this difference is mainly due to their model being wrong for a rapidly rotating planet like earth. Now in order to explain this large dubious difference between observed and their model, they proceed to invent a way to explain the difference. Their argument that temperature is driven by pressure is just pure non-sense. There is nothing in their argument that prevents me from arguing that temperature is driven by pressured. The ideal gas law does not tell you the causality. What they did manage to show with their data is that the ideal gas law holds very well for all planets with an atmosphere. Onto their main claim: The surface temperature is governed by nothing more than the solar irradiance and surface pressure (i.e. Ts=f(S0, Ps )). This analysis is fundamentally flawed. In the previous section they've demonstrated precisely that the ideal gas law is a good model for the atmosphere, which implies that there is a strong relationship between surface temperature and pressure. If they don't remove this effect, they are essentially asking how temperature depends on temperature itself, rendering their analysis moot. I have to check the above carefully, though my intuition tells me that this is not right) Even ignoring the above, they have eight data points, where two (mercury and the moon) is fitted automatically with the choice of function. They are left with 6 data points, and they have FOUR free parameters in their best fit. If this is not curve fitting, what is? -
Jose_X at 16:41 PM on 29 February 2012Radiative Balance, Feedback, and Runaway Warming
gallopingcamel, 1: I called it curve fitting partly because I skimmed very fast on my first pass and saw very few equations. It seems the curve was fitted to data points, that it was derived through linear regression without a core physical model to justify the form and approximate values of the equations. When you derive something from more basic physical principles you leave a clear math trail that shows how the formulas led to the solution. No such trail exists was apparent, and, even if computers did much of the work of solving complex equations, I would have expected to see summarizing details of such equations. The only thing discussed significantly (that I noticed when skimming) in section 3 or 4 was pv=nrt. Even if that was at the core, you don't get the two exponential terms with very precise exponents by calling praising pv=nrt, but you can get it from a good computer program doing linear regression (which they acknowledged fit the data very well). If you want to point out to me the model/math from which their two exponential terms fall out, please do so, as it would save me time. 2: Ultimately I might be convinced that the "greenhouse effect" does not dominate. I have not derived any answers, so I don't know. I do find the greenhouse effect reasonable, and I give the benefit of the doubt that others have used computers to produced the math that separates the roles done by convection from that done by radiation (maybe this hasn't been done yet, I don't know). I don't doubt DLR and the radiation effects; however, while absorption might happen at a rate dictated by radiative theories, LTE and convection (or something else) can certainly mean that the lower gases absorb in much higher concentration than they emit. Emission can still be naturally based upon the local temperature which is regulated through some other mechanism (eg, convection) to match a natural (gravitational potential based?) lapse rate. In fact, this idea basically comes from current radiative theories (I think), except that they might not be realizing that the convection effect, when the proper physical solution is derived, dominates whatever extra absorption potential more CO2 would produce [to absorb more easily would have no effect on emission rate thanks to LTE, convection, and lapse rate tendencies, for example.] -
PT_Goodman at 16:29 PM on 29 February 2012Climate change models underestimate future temperature variability; food security at risk
logicman @ #1: In the Western New York State area and, I assume, in a considerably larger area we are having "snow drought" this winter and temperatures are generally above average. Snow fall is well below average...I believe about half of normal so far this winter. No real end in sight to the current weather pattern. We do get some now from time to time, but not much. This is an extreme contrast to last winter when, after 10 months of above average temperatures in 2010, we got hit hard in Dec. 2010 with cold weather and one snowfall of 48", a record snowfall for my small town. We made the national news on two major TV networks. I doubt that we've had 48" of snow this entire winter so far. And last year, the weather continued to be cold and snowy throughout the winter. Really a miserable winter and people could not remember one like it. Of course this set the climate skeptics to saying "see, the climate *is* getting colder." It's the variability of the weather recently here in my area that seems most striking, with winters seemingly swinging to extremes one way or the other. -
Doug Hutcheson at 16:24 PM on 29 February 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
owl905 @ 20, Thanks for the reply. I think the penny has dropped: For a given stable level of insolation and a given level of CO2, the surface temperature will be a constant inversely related to the temperature at the top of atmosphere. The radiation at TOA plus the energy of the heat trapped near the surface equals the energy provided by the insolation. By adding CO2, we are keeping constant insolation, but trapping more heat near the surface, so the TOA becomes cooler, to keep my equation in balance. So, for any increase in CO2, we will see TOA cooling and surface warming, but the whole equation remaining in balance. Have I understood correctly? -
BaerbelW at 16:12 PM on 29 February 2012German translation of The Debunking Handbook
chriskoz - Actually, we had already almost finished the German translation when we learned that the iPad app of a big German newspaper (Süddeutsche Zeitung) published an article about The Debunking Handbook. The article was therefore based on the English version as the German translation wasn't quite ready yet for publication. -
owl905 at 16:01 PM on 29 February 20122012 SkS Weekly Digest #8
Site lists are about the same here, with some daily visits to: Current Global Temps Solar Activity Arctic Ice (30% concentration) Arctic Ice (15% concentration) currently offline -
owl905 at 15:55 PM on 29 February 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
Doug H @19 "What I am missing is why the top of atmosphere does not warm as well" Just to hit the spin button, the outer atmosphere actually cools during the early imbalance. Wundergroun NOAA Straosphere Chart It's coupled to earlier research that showed a connection to solar cycles and stratospheric temperatures. It doesn't "warm as well" because the same amount of heat is ... (drum roll) ... being trapped at the (near-)surface. -
gallopingcamel at 15:19 PM on 29 February 2012Radiative Balance, Feedback, and Runaway Warming
Chris @43, During our debates on "Science of Doom", Leonard Weinstein and I pointed out that for Venus it would make little difference to the surface temperature if the CO2 were replaced by an equal mass of Argon or Helium. In case you have forgotten, here are the links: http://scienceofdoom.com/2010/06/12/venusian-mysteries/#comment-2949 http://scienceofdoom.com/2010/06/12/venusian-mysteries/#comment-2953 The DALR depends on efficient heat transfer processes. In the troposphere of rotating planets heat transport is primarily achieved through convection and baroclinic eddies (mixing). Radiative processes are important only in the stratosphere where the lapse rate is usually of the opposite sign (temperature rises with altitude). Like Weinstein and this camel, N&K conclude that gas composition has an insignificant impact on planetary surface temperatures. Observations support this idea. As this thread includes "Runaway" warming let me say that if such a thing were possible it would surely have occurred during the last billion years and we would not be having this discussion. Here is a comparison between the IPCC's models that include strong positive feedbacks with one that places more emphasis on natural processes. Please note that Scafetta is making some progress on quantifying the processes that support his model using the ACRIM satellite: http://wattsupwiththat.com/2012/01/09/scaffeta-on-his-latest-paper-harmonic-climate-model-versus-the-ipcc-general-circulation-climate-models/ I must confess to some bias as Nicola Scafetta and Robert G. Brown are members of the Duke university physics department as I was for many years. We don't always agree but they have my respect and admiration. Jose_X @48, The references I provided are from physicists who are applying thermodynamics, Stephan-Boltzman etc. To dismiss this as "curve fitting" tells me that you need to take another look at the equations. -
Doug Hutcheson at 15:13 PM on 29 February 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
Tom, thank you for this post, especially the list of points:- That if you reduce the escape of heat, but do not reduce the incoming heat, things warm up;
- That the atmosphere contains molecules that absorb Infra-Red radiation;
- That radiated energy depends on the temperature of the radiating object; and
- That the atmosphere gets cooler as you get higher, so that the Infra-Red absorbing molecules in the atmosphere radiate less energy to space than they absorb from the surface.
-
skywatcher at 14:58 PM on 29 February 2012Greenhouse Effect Basics: Warm Earth, Cold Atmosphere
#17 heijdensejan, hmmm, the skeptic choir clearly does not read any literature, where there is ample empirical evidence. Tom's OP provides one part of that evidence, but there's plenty more: 10 indicators of a human fingerprint on climate change Empirical evidence that humans are causing global warming And will it be a lot?: Empirical evidence for positive feedback lots of evidence for high climate sensitivity Two of the 10 human fingerprints in the first link show increased downwelling longwave radiation and reduced outgoing longwave radiation at GHG-specific wavelengths, which are direct observations of the enhanced greenhouse effect. Skeptics don't mention them too much... -
Composer99 at 14:44 PM on 29 February 20122012 SkS Weekly Digest #8
I read Deltoid regularly because I read a bunch of other ScienceBlogs blogs. Not much else on climate science. I live in Eastern Ontario. Incidentally, in this comment I linked to a report by CFI-CASS in Canada documenting a course taught at Carleton University recently which featured a great deal of climate science misinformation. Interestingly, the CFI-CASS report links to a lot of Skeptical Science posts on climate science as additional reading. -
Albatross at 14:40 PM on 29 February 2012Satellites find over 500 billion tons of land ice melting worldwide every year, headlines focus on Himalayas
Prof. P. Body @95, I'd like echo/second your thoughts. Additionally, first people should use the correct nomenclature, traditionally "THC" refers to the thermohaline circulation. Second, the oceans are obviously significantly deeper than 700 m. Third, it is strange how fake skeptics continue to focus on statistically insignificant short time periods when we know the increase in temperature and OHC is not going to be monotonic-- they will still be playing that game when knee deep in water. It is called denial. Fourth, as I show below, you are correct, the links provided do not support their claim. One wonders whether or not they will cede that fact? So, regarding this as yet unsubstantiated claim. "The rate of SLR has slowed down over the past 5 years. ARGO data, while short, shows a reduction in THC of the oceans in the 0-700M volume." This is a badly worded argument. They speak of last 5 years of sea-level (since 2007), but then go on to mention the ARGO data which has been providing more-or-less uniform global coverage down to 700 m since the beginning of 2005 (see here), so let us use those data. I downloaded them from here. So the fake skeptics can check the numbers themselves. Since 2005 the 0-700 m global OHC has been increasing at a rate of 0.28x10^22 J/year, or increase of about 1.97x10^22 J between 2005 and 2011. So the claim that 0-700 m OHC is decreasing is demonstrably false. Further, since 2005 the 0-2000 m global OHC has been increasing at a rate of 0.732x10^22 J/year, or an increase of about 5.13x10^22 J between 2005 and 2011. But this is all for a very short period, so caveat emptor.
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