Arguments
Recent Comments
Prev 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 Next
Comments 63251 to 63300:
-
From Peru at 11:29 AM on 26 February 2012Satellites find over 500 billion tons of land ice melting worldwide every year, headlines focus on Himalayas
One thing perplexes me: How can ocean mass sea level rise be accelerating (due to accelerating melt in Antartica and Greenland) while total sea level rise has not done the same thing? During 1993-2011, we have had a nearly constant rate of 3.2 mm/yr of SLR:
Even worse, for 2003-2011 the linear trend dropped to 2.55 mm/yr:
Source: AVISO
One could think that steric sea level rise (a change in sea level caused by temperature and salinity changes)has slowed, balancing the ocean mass sea level rise acceleration, but that is not true:
Source: NODC
Where is the missing sea level rise?
-
Tom Curtis at 11:14 AM on 26 February 2012Radiative Balance, Feedback, and Runaway Warming
Charlie A @21, I believe climate scientists use the term "net positive feedback" to mean that the feedback including the Stefan-Boltzmann radiation term is positive, ie, that the temperature response of the initial forcing plus the feedback is larger than the temperature response of the initial forcing alone. -
Tom Curtis at 11:01 AM on 26 February 2012Positive feedback means runaway warming
David Lewis @109, in that lecture, Hansen says,"Our model blows up before the oceans boil, but it suggests that perhaps runaway conditions could occur with added forcing as small as 10-20 W/m2."
A 10 W/m^2 forcing, the lower limit of the range where a runaway greenhouse effect could be caused represents a 2.7 times doubling of CO2 concentration, or 1800 ppmv. To put that into perspective, the complete combustion of all currently known and speculated oil, gas and coal reserves would raise the CO2 concentration in the atmosphere to 1366 ppmv, or approx 8.5 W/m^2 forcing. Even where we foolish enough to do that, we could not realistically do it in a century, so there would be plenty of time to turn back from our folly. What concerns Hansen is the possible massive release of Methane from clathrates and from thawed tundra adding over 1000 ppmv of CO2 to the atmosphere; or if done quickly enough, acting as a direct forcing of much greater magnitude. Fortunately the probability of a methane release of that magnitude, or a rapid enough methane release to lift the forcing over the 10 W/m^2 level for the possibility of a runaway greenhouse effect is remote. I note that Hansen indicates that the run away effect is a "dead certainty" not only if we consume all coal, but also all tars (shale oil & tar sands). That indeed would lift CO2 concentrations above his lower limit for possibility, which together with a clathrate gun is would lift CO2 concentrations beyond the level where his model blows up. Again, however, this is not a prospect for this coming century because we cannot consume the coals fast enough on any likely economic scenario. More to the point, Hansen is simply wrong about this prospect, as is elegantly discussed by Chris Colose in his recent blog post on SkS. The upshot is, if we go for a suicide pact (burn all tars and coal), we can in fact make large portions of the planet literally uninhabitable by warm blooded creatures; but we cannot turn Earth into another Venus, or extinguish all life on Earth. (If nothing else, hypothermophiles will continue to hold on in geysers and ocean ridges. I'm sure that is a comforting thought. -
YOGI at 10:57 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
I will read the Trenberth guest post and comment later, thank you. -
Tom Curtis at 10:32 AM on 26 February 2012Monckton Misrepresents Reality (Part 3)
JoeTheScientist @2, No! And nor do we want to. Even on an issue so important, science works by the open exchange of ideas. Well, actually it works by the open and honest exchange of ideas, so what Monckton does is anti-science, but because of the way science works, it can only defend itself by the open exchange of ideas. As soon as scientists think they can rely on more than that, they kill that which they are trying to defend, as Lysenko did in the Soviet Union. -
IanC at 10:26 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
Yogi 1338, If, hypothetically speaking, the source of heat on earth is internally generated, would you, in this case, agree that the earth will be warmer with water vapour present compared to the case without?Moderator Response: [JH] Please do not feed the troll. -
YOGI at 10:24 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
"[DB] You are advised to read the entire thread above, as your fallacy has been corrected several times already." Nutshell it for me now if you can, unless you can link me to the relevant comment, I`m not going to read all the comments for it.Response:[DB] If you cannot be bothered to read work already done, there for inspection, then why should anyone here engage you? Perhaps if you succinctly narrow down your objection to the one thing you want to hang your hat on then someone here will be able to help you.
Unless your goal is to simply waste the time of others. As also has been evidenced on this thread.
-
YOGI at 10:20 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
Response: [JH] Your propensisty to post factoids without context...... It was not out of context. I was commenting on the SOD link at #1333. And the data shows that daily min/max soil temp`s range less than the atmosphere.Moderator Response: [JH] You are skating on very thin ice. Please cease and desist. -
solarsparky at 10:16 AM on 26 February 2012Satellites find over 500 billion tons of land ice melting worldwide every year, headlines focus on Himalayas
Excuse my ignorance, what does,"the red spot in Africa is an artifact" mean and why do we have blue spot in the Pilbara region of WA,yes there is geological evidence of ice sheets at Marble Bar, but certainly not in the time these satellites have been recording data? -
YOGI at 10:12 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
#1336 "Are you warmer if you cover yourself in a blanket than you would be without the blanket? Yes of course you are, because the blanket back-radiates some of your body heat." Unlike the Earth I am internally heated so the analogy is not safe, but if the blanket is bright white, it could be handy to reflect the sunshine on a really hot day. But for an externally heated system such as Earth, to have 235W/m go in and out, but to reach 390 watts within the system is impossible: [link]Moderator Response:[DB] You are advised to read the entire thread above, as your fallacy has been corrected several times already.
Additionally, you would be wise to read this guest post by Dr. Trenberth for yet further exposition into the subject. It contains this updated version of the graphic you link:
[RH] Hotlinked url that was breaking page format.
-
JP40 at 10:12 AM on 26 February 2012Global Extinction: Gradual Doom as Bad as Abrupt
The technology needed for accomplishing a task isn't a guarantee to it getting done. We see this now with space travel exploration, but it also applies to climate change issues. Just because we know how to build wind turbines, solar plants, indoor airoponic farms, and sea barriers, doesn't mean we will be able to stop a collapse of civilization due to climate change and overpopulation related problems. The main problem in the western world, and especially America is the capitalist economy. A large corporation, as a collective entity of people pursuing their personal goals, has absolutely no intrest in reducing its profit margins, in the long term intrest of helping our civilization survive. That, and the fact that politics works a similar way, with politicians only concerned about getting reelected, Is the main reason why climate change denial is so wide-spread. In WW2, the government ordered car companies to start making tanks, jeeps, and aircraft. If a strong-willed president tried that today, with renewable energy, he/she would be called a commie and would get almost no support from congress. Technology is useless if the power behind the money needed to implement it won't act in the long-term best intrest of its people. -
JP40 at 09:22 AM on 26 February 2012Global Extinction: Gradual Doom as Bad as Abrupt
Bernard J. - I agree with you that for humanity to survive on earth, and for the earth to survive, we need far fewer people living on it. But, I strongly dissagree with your dismissal of the possibility of colonizing space. The amount of energy required for moving people that far is mostly irrelevant, because there is no friction in space. After a spacecraft reaches its cruising speed, it doesn't need to fire its engines until it reaches its destination. As Robert Heinlein said "Get to low earth orbit and you're halfway to anywhere in the solar system." Most of the massive Saturn-5 rocket that sent the Apollo astronauts to the moon was just to get the rocket out of the atmosphere. We have the technology right now to colonize the moon and put a permanent outpost on Mars. It's only a matter of a government putting the 20-30 billion USD required into its space program. The only other issue is time. Using our current rocket technology, it takes 1-2 earth years to get to Mars. I liken it to the age of exploration in the 1500s. Where people decided to get on a boat and start a new life in the "new world." People then couldn't imagine that now we can cross the Atlantic in a few hours. With radiation protection, people could live their entire lives on Mars, or rotating space stations. Probably not on the moon, because of the affects of low gravity on people. Getting back to the topic, if human damage to the environment triggers the same chain of events as in the P-T extinction, settlements in space could be the only way to preserve our civilization and our species. As Carl Sagan said "All civilizations become either spacefaring or extinct." -
owl905 at 08:53 AM on 26 February 2012Radiative Balance, Feedback, and Runaway Warming
@Saurj 16 - thanks for the expansion. For the purpose of ChrisC's review, maybe ppmv would work. @ChrisC - After three rounds of Moncton and the greatest extinction in the history of earth, explaining blackbody, sensitivity, and the temperature/gas dance with a few simple graphs ... is a grand slam. Maybe you could send this to the guys at The Big Bang Theory ... even Penny might get this one. -
JMurphy at 08:29 AM on 26 February 2012Medieval Warm Period was warmer
cjshaker, there's a nice 'hockey-stick' available at the first link you provided :
-
Charlie A at 08:25 AM on 26 February 2012Radiative Balance, Feedback, and Runaway Warming
This is an areas where semantics and precise meanings DO matter. Many climate scientists use the term "net positive feedback" to mean that all second order feedbacks other than the Stefan-Boltzmann radiation term are positive. That is quite different than a true net positive feedback, where the positive feedbacks are larger than the negative feedback of ithe increase in radiation caused by the increase in temperature. -
YOGI at 08:20 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
#1333 S.O.D. article: "Notice that DLR does not drop significantly overnight. This is because of the heat capacity of the atmosphere – it cools down, but not as quickly as the ground." http://scienceofdoom.files.wordpress.com/2010/07/dlr-billings-ok-1993-2wks.png Thats bigger than some of the seasonal variation !Moderator Response: [JH] Your propensisty to post factoids without context is wearing very thin. It's like someone throwing gobs of paint against a wall and hoping that some will stick. At the end of the day, the wall is a complete mess. Please cease and desist. -
Bob Lacatena at 08:09 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
Yogi, Let me state this clearly. You are wrong and confused. You are religiously clinging to a misunderstanding of the science. You do not need Dikran or anyone else to walk you, step by painful step, through the thought process. What you need is to simply say to yourself "gee, maybe I don't understand all this, and I should open my mind, and go read and learn, and then come back when I have a better understanding of things." Trying to convince everyone else that you know better than all of science is a waste of everybody's time. -
Dikran Marsupial at 07:58 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
YOGI Sorry, nobody can say I haven't been extreemly patient with you, but again you are playing word games. Nobody has said that back-radiation makes the surface warmer, just that it makes the surface warmer than it would otherwise be. Are you warmer if you cover yourself in a blanket than you would be without the blanket? Yes of course you are, because the blanket back-radiates some of your body heat. Likewise the back radiation from GHGs causes the earth to loose the heat it gains from absorbing visible and UV light from the sun more slowly by returning some of the out-bound IR back to the surface. I have had more than enough of this discussion; had you behaved better I would continue, but life is just too short. -
YOGI at 07:44 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
#1331 If I agree that the back-radiation from the water vapour causes the ground to be warmer than it would otherwise be, that is paramount to saying that it heats the ground. It does not and cannot, as it is colder than the ground, it merely slows the rate of cooling, not warms it. -
scaddenp at 07:42 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
YOGI - you can verify some of this by actually comparing the measured backradiation in a desert compared to somewhere humid. Remember this is measurable properties here. Eg look at the SoD articles on DLR. In part one, you see the spectra for incoming versus outgoing. In part two, there is DLR measurements for Alice springs versus Billings OK. Read and understand. -
YOGI at 07:39 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
#1325 There are some absorption bands in the solar IR but plenty gets through. And IR penetrates into the surface of land like radio waves do. http://en.wikipedia.org/wiki/File:Solar_Spectrum.png [Snipped] -
Dikran Marsupial at 07:39 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
YOGI O.K. well lets revisit the original question, which was: "So what happens in a desert at night, does the CO2 back-radiation turn off when the sun goes down ?" We now know the answer, it isn't that the CO2 back-radiation turns off when the sun goes down, it cools more quickly because there is less back-radiation from water vapour because the atmosphere above the desert is drier. In fact the rapid cooling of the desert at night is a common example used to demonstrate the existence of back-radiation. Now your most recent post is essentially just blatant rhetorical evasion. If the back-radiation from water vapour causes the surface to "cool down slower", then at any point in time after nightfall it will be warmer than it would be if the water vapour were not there, precisely because of the difference in the rate of cooling. The reason why you want to evade admitting that the back-radiation causes the surface to be warmer than it would be if the water vapour were not there is obviously because you would then be forced to concede that the surface would be warmer than it would otherwise be if not for the back-radiation from CO2. Frankly getting to this point has been like getting blood out of a stone, and I can't see why you should think anyone will be willing to engage in a scientific discussion with you if you are going to behave in this manner. I am sorry to have to strongly suggest to everybody "DNFTT". -
Dikran Marsupial at 07:29 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
Can I suggest we ignore YOGI's comment above until we have reached the end of the discussion about deserts. The errors in YOGI's post about solar IR are pretty obvious and begging for an answer, but it would be better if the answer were delayed for a while. -
YOGI at 07:27 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
#1327 No it causes it to cool down slower. -
YOGI at 07:26 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
#1325 Solar near IR is forty something % of the heat input from the Sun. You never heard of IR blocking windows ? its the solar thermal IR they are blocking, not DLR. -
Dikran Marsupial at 07:23 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
YOGI I didn't say that it would warm the surface up, I said it would be warmer than it would if there were no water vapour in the atmosphere (and therefore no back-radiated IR). Do you agree that the back-radiated IR from the water vapour in the atmosphere would cause the surface to be warmer than it would be if the water vapour were not there? -
YOGI at 07:18 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
No, it just reduces the rate of cooling, it cant warm it up. -
scaddenp at 07:16 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
"Insulation, it cant warm the ground though unless its warmer than the ground." The "insulation" effect is radiative. A quick look at the thermal properties of moist air (conductivity, heat capacity) cf dry air, would tell you that conductive insulation isnt at work. Do the math. As to your "greenhouse". Incoming radiation from sun isnt in IR range (that is whole point) so no, it would heat up slower. If you have really read the SoD articles explaining the science here, you are showing little evidence of it. -
Chris Colose at 07:12 AM on 26 February 2012Radiative Balance, Feedback, and Runaway Warming
corrected- thanks -
keithpickering at 07:10 AM on 26 February 2012Radiative Balance, Feedback, and Runaway Warming
Very clear explanation, and excellent graphs, thanks. One quibble: From these figures, we can readily see the fallacy is "positive feedbacks imply instability" type arguments. ... should read "the fallacy in" -
Dikran Marsupial at 07:07 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
YOGI O.K., so you agree that the water vapour re-radiates some IR photons back to the surface. Would you agree that these back-radiated IR photons cause the surface to be warmer than it would be if those molecules of water vapour were not there? -
skept.fr at 07:03 AM on 26 February 2012Tropical Thermostats and Global Warming
As I understand the question, there is really a kind of thermostat (figure 1 from Argo is clear, and most of the warmer T probably come from the 30°S-30°N zone, so the rapid fall beyond 28-30 °C is probably not an artifact as suggested by Jeff on #6). But nothing says in the theory and the observations that the maximum value of this thermostat is constant when the climate is forced (or when it is different from now): we could have a future thermostat treshold at 32, 33, 34... °C, as we had past SSTs (and thermostat maximum values) hotter than now. Chris #12 : isn't Lindzen's "Iris Effect" a kind of tropical thermostat (less cirriform clouds > more IR radiation escaping to space)? If so, it took less than 20 years, the seminal paper about Iris is rather published in 2001. -
YOGI at 07:03 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
#1322 ok there may an exchange but it cant get cool off in the direction of the warmer body, as the warmer body is warming it faster than it can cool off. -
Dikran Marsupial at 06:58 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
YOGI wrote "It will want to radiate it towards somewhere colder." O.K. so when a molecule of water vapour in the atmosphere emits a photon of IR, how does it know not to emit it in the direction of a warmer body? -
YOGI at 06:56 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
Dikran Marsupial "O.K. so the water vapour absorbs the IR radiated from the ground and then warms up. What happens to the heat energy that the water vapour has acquired in this way?" It will want to radiate it towards somewhere colder. But while it is warmer, it will mean the ground will lose heat slower, remember my cup of tea ? ~ insulation. "insulators do not work by reducing the rate at which something radiates photons of IR" Paint your roof white and it will do exactly that. -
Dikran Marsupial at 06:50 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
IanC can I suggest we leave YOGIs greenhouse until we get to the conclusion of the discussion of why the desert cools rapidly at night. We won't make any progress in this discussion if it keeps branching out onto new thought experiments before the earlier ones have been resolved. -
JoeTheScientist at 06:48 AM on 26 February 2012Monckton Misrepresents Reality (Part 3)
Can't we start arresting some of these frauds for, well, fraud?? -
neil at 06:48 AM on 26 February 2012Search For 'Missing Heat' Confirms More Global Warming 'In The Pipeline'
Ok, I'm going to try one more time, then I'm out. Like I've said, you have a point about aerosols, but you are wrong on carbon-induced warming. I think I can identify the source of confusion. There is a difference between "past emissions" and a "constant composition atmosphere". The fully-coupled models used for IPCC AR4 were only 'physical' models. They did not contain carbon-cycles, so carbon could not be advected around or exchanged between natural reservoirs. Instead, atmospheric CO2 concentrations are specified in this class of models. Common scenario's included an instant doubling of CO2, or a 1% increase in CO2 per year. Ok, now lets consider what happening is these model results, which we are familiar with. In the scenario where CO2 is increased, and lets say set to 450 ppm - the surface temperature takes hundreds, or thousands of years to come into equilibrium (this here is your "warming in the pipeline"). Even if CO2 is increased slowly at say 1% per year, rather than instantly, it takes hundreds of years for equilibrium to be reached (because of the slow-adjustment of the ocean some people here have talked about). However, the key to realize is that in order to maintain an atmospheric CO2 of 450 ppm, you need a constant source of emissions. If there were no emissions, the ocean would take up carbon, and the atmospheric CO2 would drop below 450 ppm. However the AR4 models could not diagnose what emissions were consistent with keeping CO2 at 450 ppm, since they did not contain carbon cycles. The set of intermediate complexity earth system models (such as UVic, Bern, Climber) do contain carbon cycles, and could diagnose the emissions consistent with keeping CO2 at 450 ppm. Also, the new generation of fully coupled models being used currently in CMIP5 / AR5 are earth system models (or carbon-climate models), that are capable of tracking carbon through the system. So, for a constant composition atmosphere, surface temperatures take hundreds of year to come into equilibrium (but, keeping CO2 constant also requires some ongoing emissions). For zero emissions, (or the commitment to past emissions), there is no future warming, as explained previously. @Rob 45 That makes no sense at all. How can the ocean warm without eventually exchanging that heat to the atmosphere? Don't get confused between heat and temperature!! The ocean can absorb a massive amount of heat, but the average temperature of the ocean (and particulalrly the deep ocean) will remain below the temperature of the surface! Thus the direction of the heat flux remains downward! -
YOGI at 06:47 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
IanC#1318 So from the IR intensity Earth looks a lot colder from 20km up than it really is on the surface. Did you like my greenhouse in #1307 ? -
scaddenp at 06:46 AM on 26 February 2012Medieval Warm Period was warmer
Chris, in what way do you think Cook & Palmer challenges consensus? (I mean its used in the Mann/Jones 2003,2004 papers). Also did you follow up and look at their 2006 paper. Of course, MCA/MWP is example of natural variability. But not of unforced variability. Instead of cherry picking particular proxies, tell what is wrong with the methodology of the Mann 2009 paper which integrates them all for a global picture. -
Chris Colose at 06:33 AM on 26 February 2012Radiative Balance, Feedback, and Runaway Warming
sauerj- I wouldn't have thought that the article was that exciting, but glad I could help! I didn't show graphs with different CO2 concentrations because you'd barely see the difference between what I did, and say, an 800 ppm experiment. Keep in mind that the forcing for 2xCO2 is something like 4 W/m2 and I'm plotting the y-axis on these graphs over a range of many hundreds of W/m2, so it won't show up well unless you go to CO2 levels much higher than we're really worried about for future global warming. And it turns out that the OLR threshold at which it start to level off and become independent of temperature doesn't depend too strongly on the CO2 concentration. -
IanC at 06:27 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
YOGI 1302, Our discussion up to post 1290 is related to the figures in the article. If you read the caption that came with the figure, you'll notice that 265K, instead of 287K, will be the more sensible surface temperature. "The closer you get to the surface the less absorption there is from the 600-750 band, and the majority of the effect is above 3km." No. Absorption increases with density. Since the density is the greatest near the surface, the absorption is the greatest there too. -
Dikran Marsupial at 06:24 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
YOGI O.K. so the water vapour absorbs the IR radiated from the ground and then warms up. What happens to the heat energy that the water vapour has acquired in this way? n.b. insulators do not work by reducing the rate at which something radiates photons of IR (that depends on its temperature) -
YOGI at 06:19 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
If I take my cup of tea out in the cold night air it will cool quicker. Same for the ground, but if there is more water vapour above it will absorb IR from the ground, warm up, and reduce the rate at which the ground can then radiate. -
WheelsOC at 06:15 AM on 26 February 2012Radiative Balance, Feedback, and Runaway Warming
I'll add my voice to the chorus on clarity! On a side note, isn't it interesting to see how Monckton thinks the positive feedbacks play into this? According to his wording, the IPCC imagines them. Pretty sure that these actually originate from physicists and other earth scientists who study the atmosphere, write the literature on it, and that literature is then eventually summarized by the IPCC. Even the models they use in the report are set up and run by scientists for their own purposes, not for making IPCC reports. It betrays some of the mindset that it takes to shrug off such a strong, facts-based, scientific consensus: "This must not be coming from the majority of working scientists trying to make sense of the planet, it must be coming from the United Nations' political machinery and their need to support the Big Government Wealth Redistribution Agenda!" or something along those lines. -
sauerj at 05:55 AM on 26 February 2012Radiative Balance, Feedback, and Runaway Warming
Chris Colose, Well done! ... I am a chemical engineer. It is beaten into our heads to relate things with graphs as doing so shows relationships so well. As of yet, I've never seen anyone explain 'sensitivity' so well as you have done. Sensitivity is simply the 'gain' or 'multiplier' that relates a change in an independent variable (i.e. forcing, such as CO2) to a change in the dependent variable (temp). In formula form: dT = Sensitivity x dCO2. Essentially, S is the SLOPE on a graph. (For a graph formatted with Temp on the x- axis as in the article, Sensitivity would actually be '1/slope'.) And, WOW!, your article shows this visually so well! It clearly shows how a more horizontal sloped curve (for Flux vs Temp formatted graphs) versus a more vertically sloped curve result in HIGHER sensitivities. This is the kind of technical (but yet simple) explanation that will turn the heads of the more technically astute minds out there (assuming they are the least bit open-minded)! This is the kind of stuff that might get them to say, "Oh! Now I get it!" Like, @4 chriskoz and @7 Pirate mentioned, I would propose a PART-2 follow-up article which I think would knock this whole thing over the fence. Then, I would feel fully ready to explain the science of global warming amply loaded with the needed ammunition that could NOT be refuted. I can only wonder if such an addendum would also be universally helpful. Here is the suggestion: After Fig.3, I would take the article on a slightly different course. For the next graph, I would show two RED curves; one for 250ppm (pre-industrial) and another for 500ppm (give a hypothetical year, 2065). Why 250 & 500 curves? These CO2 values work well with the typical scientific talk of doubling CO2 and how such a doubling impacts temperature. Plus it shows realistic resulting temperatures for a starting point (pre-ind) CO2 and not-so-far-away (2065) CO2. ... Leave the horizontal line at 240 W/m2 (at this point in the article assume albedo differences and solar cycle variances are still neutral). With these two CO2-only RED curves, I would expect the difference in equilibrium temp to be ~1.0 - 1.2K, which I have read on this site as the expected dTemp for doubling of CO2 with NO other feedbacks mixed in. Then, on this same graph, add two BLUE curves representing the average Relative Humidity earth conditions, one at 250ppm CO2 and the other at 500ppm CO2. I assume the '500ppm w/RH' curve will simply be shifted down below the '250ppm w/RH' curve (you would know the exact particulars on this better than I). If you look at the present Fig.3, I see how, at 200K, the RED curve is shifted vertically down below the BLACK curve, and the BLUE curve (at this 200K) also "starts" at this same point (at this trace humidity state). For the 250ppm & 500ppm RED & BLUE curves, they will simply start (at the 200K temp) at two different vertical shifts down from the BLACK curve, with the 500ppm curve simply being 'LOWER' than the 250ppm curve (probably by the same porportional vertical distance). Then, when these curves move to the right from this starting point (200K), they will cross the 240W/m2 horizontal line at their various equilibrium temperatures. [Slight diversion: WOW, your article is so COOL how it visually explains these changes in the equilibrium point. With your clear graphs, any technically oriented person would instantly understand & get your point and realize its significance in a heartbeat!] Since the two BLUE curves are so much flatter (i.e. or lower angle, or read higher sensitivity), the horizontal distance between the two BLUE curves will be much greater than the horizontal distance for the RED curves, i.e. a much higher sensitivity. Therefore, the 1.0-1.2 dT for doubling of CO2 alone turns into ~3.0dT when adding in the humidity feedback. ... This would really help explain the positive feedback of humidity added on top of doubling CO2 alone. After this, I would take the article the direction as proposed by @4 chriskoz. This graph could show the impact on Temp caused by an extreme change in solar radiation, such as during the Maunder Minimum, but I would like to see the article stay more applicable to today's typical solar cycles. Therefore, I would setup this next graph to show the resulting dT between 1) a LOW POINT on our current measured SOLAR CYCLES and 2) a HIGH POINT on our current SOLAR CYCLES. I don't know what the difference in average, earth-surface, net input W/m2 for these two points amounts to ... ~0.25W/m2??? But whatever it is, show these two horizontal lines super-imposed on a "detailed" view of the graph ('detailed' so to better see the dT impact). I expect this equilibrium dTemp impact to be roughly 10% (or less) than that for the CO2 doubling w/ RH impact (~3.0dT). I recall reading on this site that modern variances in solar radiation amounts to (at most) 1/10th that of human induced CO2 changes. owl905: Your point about 400ppm (or 1,000,000 ppm) is NOT a small point! And, the article probably needs to be tweaked a bit in its wording to assure absolute accuracy. The greenhouse effect of CO2 can NOT be ONLY a function of its %concentration (PPM) amongst the rest of gases. Instead, it HAS to be a function of actual #moles per unit volume of CO2 in the atmosphere (or, more clearly for most people, MASS per unit volume). These two are not the same; a given PPM does NOT mean a set MASS/volume concentration. For example, imagine an atmosphere that only had 1/10 the mass (in the entire atmosphere) of N2 and O2 (these being non-greenhouse gases). Then, let's only add CO2 to this hypothetical atmosphere; thus it is the ONLY greenhouse gas in the atmosphere. But, let's add the CO2 to a %concentration of 400ppm, then obviously the mass of CO2 (per unit volume) would be 1/10 of our present atmosphere. There is NO WAY this 1/10 mass/volume CO2 atmosphere could have the same greenhouse effect as our present atmosphere. The point here is that the key driving variable HAS to be MASS/volume NOT % of molecules which, technically, is all that PPM really states. Therefore, the key variable defining greenhouse effect is not PPM, but actually mass/volume or molecules/volume (however you want to express it). But, this detail is getting TOO technical for most people to understand & it deviates from the usually 'talk' of defining the greenhouse effect as a function of PPM. So, I would simply say (for Fig.2) that you would first "flood the atmosphere with present day quantities of N2 and O2, then add CO2 to the concentration of 400PPM". Then, explain that the N2 & O2 cause NO greenhouse effect, so you have created an artifical atmosphere that has a CO2-only greenhouse effect that would mimic today's atmospheric "concentration" of 400ppm of CO2 (this being your original intention in Fig.2) ... without explaining the detail that this also means that this hypothetical atmosphere would also have the same mass/volume concentration of CO2 as today's atmosphere. This slight wording tweak ("400ppm in the same N2 & O2 atmosphere as per today's atmosphere") would then be technically fully accurate and defendable. Sorry for LONG comment. I tend to get too windy. -
Tor B at 05:51 AM on 26 February 2012Radiative Balance, Feedback, and Runaway Warming
Thanks for the clear and informative explanations. Thinking about various variables that affect sensitivity, I'm reminded of Richard Alley's incredible 2009 AGU lecture "The Biggest Control Knob: CO2 in Earth's Climate History" . It appears the 11-year solar cycle will cause greater temperature swings (within an equilibrium system) when the temperature is higher, lets say due to increased atmospheric CO2. Will this make future weather events more chaotic or less "average" (whatever is the new climatic average)? In our current not-in-equilibrium Earth system, the effects of the recent extended solar minimum (plus increased aerosols & La Nina) appear to have virtually countered temperature increases due to increasing CO2. I've read someplace that climate scientists are functionally certain that new global surface temperature records will occur within several years, at the latest. I presume this is because of the influence of both increasing CO2 and increasing solar radiation, regardless of what happens with ENSO or air polution. (SkS article about Dr. Alley can be found here.) -
Dikran Marsupial at 05:50 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
YOGI O.K. so how does it insulate the ground? IR is radiated from the surface, then what happens to it? -
YOGI at 05:45 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
Insulation, it cant warm the ground though unless its warmer than the ground. -
Dikran Marsupial at 05:25 AM on 26 February 20122nd law of thermodynamics contradicts greenhouse theory
YOGI O.K. so *how* does water vapour slow the loss of heat at night (we can move onto the day later)?
Prev 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 Next
