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Marcus at 15:38 PM on 17 April 2011What was it like the last time CO2 levels were this high?
Wow Gilles, you're an even bigger piece of work than I thought you were-& that's really saying something. Here you've been, telling us over scores of postings, how you believe consumption of fossil fuels is necessary to save the lives of people in the developing world-yet clearly you don't give two hoots about human life, you only care that the world consumes more of your precious fossil fuels, & damn the consequences. Also, like any good denialist, you believe that repeating the same myths will somehow make them true-like your false FF consumption correlates with population growth meme. Well guess what? It was wrong before, & its still wrong now. China has had a much bigger growth rate than the Western Hemisphere-dating back to the middle ages. Was that because they had coal-fired power stations the European World wasn't aware of? No, its because they had much better medicine, education & sanitation than the Europeans. Its also funny that China's growth rate, over the last 30 years, has been less than any time during at least the last 500 years-yet their fossil fuel consumption in the last 30 years has been at its highest during that same time-frame. Kind of knocks your ill-founded "correlation" fantasy on the head, doesn't it? Similarly, population growth rates in the West actually started to climb significantly around the end of the 18th/start of the 19th century. Again, improvements in health care, sanitation & income distribution seem to be the most likely causes. Also, according to what I've seen, yearly growth rates have fallen from around 2% per year in 1970 down to around 1.2% per year in 2010-not exactly great evidence for your "correlation" myth, is it Gilles? Last of all, in recent history some of the biggest population growths have occurred in Countries like Thailand, The Philippines, Brazil & Mexico-in spite of the fact that their fossil fuel consumption remain far lower than those of the less populous, so-called "advanced" economies of Western Europe & North America. Again, not great "evidence" for your "correlation" myth. It seems you understand historical correlations about as well as you understand the drivers of climate change & release & take-up of greenhouse gases. That is to say-you don't understand them *at all*, & should probably go & educate yourself before you embarrass yourself even further.Moderator Response: [DB] Your spirit is appreciated, but your energy is better served someplace where productive results are achievable. Unfortunately, this is not one of those. DNFTT. -
RSVP at 15:36 PM on 17 April 2011Waste heat vs greenhouse warming
and what import does the radiation between molecules have if all they do is exchange energy between themselves? Here we have 100% cancellation of anything remotely resembling a cooling mechanism, as the only thing that matters is the net vector from the surface skyward. -
RW1 at 15:12 PM on 17 April 2011Clouds provide negative feedback
Dessler 2010 seems to be claiming that clouds are trapping more energy as the surface warms. He writes on page 3 of his paper: "Because I have defined downward flux as positive, the positive slope here means that, as the surface warms, clouds trap additional energy; in other words, the cloud feedback here is positive." Is he claiming that clouds are changing in a way that results in them trapping more surface energy? If yes, how has he rectified this with all the data (i.e. how has he shown that the additional energy the clouds trap is greater than the additional energy they reflect away)???Moderator Response: [Muoncounter] There is an existing thread for Dessler's paper; check to see if your question was already addressed. -
Tom Curtis at 15:06 PM on 17 April 2011A Flanner in the Works for Snow and Ice
Ken Lambert @68, in reviewing my calculations I noticed I did not adjust the atmospheric absorption for my error regarding angles in 54. Rather than pursue that line of calculations, I have recalculated the increase in incoming energy over the arctic summer due to the change in ice area between the early 1980's and the late 2010's. I have proceeded as follows: 1) For each half hour of the 21/5/2011, I calculated the minimum solar altituded at 75 degrees North and 0 degrees East using azimuth and altitude calculator to which you have previously linked. I then compared those values to a selection of values calculated for 20/7/2011 to ensure those of 21/5/2011 are smaller (they are). As previously discussed, these dates are chosen because they lie thirty days on either side of the summer solstice. Thus, for sixty days of the summer, the altitude will be higher than these values, and for the remaining 30 days, not much lower. Taking these values, therefore, represents a conservative estimate of the mean summer values. Having determined the minimum altitude for each half hour, I then rounded down to the nearest whole degree. 2) For each half hour, and using the result of (1), I then calculated the albedo of sea water for water incident at that angle using the Fresnel equations, the effective path length through the atmosphere as a multiple of the height of the atmosphere, and the effective surface area over which light striking one meter squared perpendicular to the light would spread on the surface (in square meters). The later two are calculated using the formula =1/(SIN(RADIANS(D55))), where the radians function converts degrees to radians, and the sin function gives the sine of an angle expressed in radians. 3) Using values for cloud albedo and atmospheric absorption taken from Trenberth's chart (in 54 above), I then calculated incident radiation at the surface in watts/m^2 for each half hour of the day using the formula: I = S * (1-C) * (1-(L*A)/area where I equals the incident radiance, S equals the TSI, C equals the cloud albedo, L equals the path length of the light where the height of the atmosphere = 1, A equals the mean atmospheric absorption , and area equals the area over which light that passes through one square meter perpendicular to the light path at the top of the atmosphere will pass. Where this formula returned a negative value, I used 0. To ensure the value was conservative, I used the TSI at aphelion, which is 1321 W/m^2 {{=IF((($D$52*(1-$G$52)*((1-($I$52*F55))/G55)))<0;0;(($D$52*(1-$G$52)*((1-($I$52*F55))/G55))))}} 3a)As a check against whether this constitutes a conservative estimate, I calculated the mean incident radiation over a day using the above method, which was 127 w/m^2. For comparison the following map shows the annual average surface solar energy including the effects of clouds and atmospheric absorption:As you can see, the average over the whole year including six months of darkness, is nearly 100 w/m^2, so my estimate for the summer months of 127 W/m^2 is certainly conservative. 4) From the half hourly values obtained in (3), I calculated the additional energy absorbed by ocean surface exposed by melting sea ice as the difference between the albedo (0.9) of the sea ice and the albedo of the ocean given the angle of incidence, multiplied by the effective surface radiation (as calculated in 3). Taking the mean of that value, the average additional power absorbed by the ocean is 97 W/m^2. 5) Using that value, I calculate the total additional energy absorbed as 7.57 x 10^8 Joules per meter squared over a notional 90 day summer, or 1.51 x 10^21 Joules over the whole 2 million square km of additional ice cap melted over the period 1979-2011. This is a reduction from my 1.7*10^21 estimate in 56, but is now (at last) error free so far as I can determine, and still a very conservative estimate. So conservative, in fact, that it assumes zero insolation for 9.5 hours of the day in the arctic summer. But it is still a sufficiently large figure to show that you are significantly underestimating the forcing effect of arctic melt back, and that there is no basis from considerations of incoming energy to think Flanner is incorrect about overall forcing.
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RW1 at 14:19 PM on 17 April 2011Clouds provide negative feedback
Sorry, but I'm not interested in a semantics debate regarding the definition 'skeptic'. ['...the system's response to GHG forcing will be much greater than it is to solar forcing...'] "This is untrue. You are the only person on the planet to have arrived at this conclusion, because your underlying model (understanding) is flawed." I don't see how this is untrue. I make no claim that it's an impossibility, but it is true that the AGW theory claims the next 3.7 W/m^2 incident on the surface will be amplified by the system nearly 3 times a much as the original 239 W/m^2 incident on the surface from the Sun. If, as the AGW theory claims, an additional 3.7 W/m^2 at the surface is to become 16.6 W/m^2 mostly through positive feedback, quantify specifically how the feedback causes this much change while it doesn't for the original 98+% (239 W/m^2) from the Sun. "But that model -- the rules and assumptions you are following -- are flawed." Explain why. -
Bob Lacatena at 13:37 PM on 17 April 2011Clouds provide negative feedback
12, RW1,I don't have a model.
Of course you do. Everything in science is a model. You have a mathematical model (a set of rules and assumptions) that you've used to derive your proposed answer from the data. But that model -- the rules and assumptions you are following -- are flawed....the system's response to GHG forcing will be much greater than it is to solar forcing...
This is untrue. You are the only person on the planet to have arrived at this conclusion, because your underlying model (understanding) is flawed....my purpose here is to present contradictory evidence and logic that disputes the theory. That's what I'm doing.
No, what you're doing is confusing people with your own personal creation of faux-math-science.I have not seen, in my estimation, these relatively simplistic things explained by the pro-AGW advocates.
No one can explain to you why 2 plus A does not equal monkeys, because it's not even a mathematical equation. Similarly, your insistence that some theory must explain your 1075 W/m2 number will never happen.I'm a staunch skeptic of AGW
That's an oxymoron. No one can be a "staunch" skeptic. Being skeptical means questioning what you are first shown until it is satisfactorily proven, not questioning it endlessly with no hope of acceptance or understanding, because you staunchly refuse to be anything but eternally skeptical.Moderator Response: [Muoncounter] We've been down this painful road before. Please do not encourage another go round. The other player in the drama is known as co2isnotevil, which should tell you all you need to know about his viewpoint. -
Tom Curtis at 13:32 PM on 17 April 2011A Flanner in the Works for Snow and Ice
DB @ KL, thanks for your good wishes. -
Bibliovermis at 13:26 PM on 17 April 2011Clouds provide negative feedback
RW1, That word doesn't mean what you think it means. A skeptic ~is~ interested in being helped. You have described something else. -
dana1981 at 13:11 PM on 17 April 2011David Evans' Understanding of the Climate Goes Cold
Nick - the number Evans gives is reasonable for the temp change avoided at equilibrium compared to business as usual. It's just small because the Aussie population is small compared to the global population. -
RW1 at 13:05 PM on 17 April 2011Clouds provide negative feedback
Sphaerica (RE: 11), "FYI... These are rhetorical questions. I don't really want to know." OK, then I won't answer. "Your entire model is invalid." I don't have a model. All of my numbers and calculations are from measured or generally accepted data. ['...why doesn't it take 1075 W/m^2 at the surface to allow the 239 W/m^2 from the Sun to leave the system...'] "You will never get an answer to this question because it is non-sensical." I'll probably never get an answer because this is a significant whole in the AGW theory that no one seems to be able to explain (that the system's response to GHG forcing will be much greater than it is to solar forcing). "I don't think that I can help you." I appreciate that you seem to be interested in helping me, but I'm not really interested in being helped per say. I'm a staunch skeptic of AGW, so my purpose here is to present contradictory evidence and logic that disputes the theory. That's what I'm doing. "There's a guy over at Nova's loony-bin site who does stuff like you're doing. If you're trying to learn by listening to him, you're only to wind up being get very, very confused." I'm not sure exactly who you are referring to, but I learn and have learned from listening to a multitude of sources - both for and against AGW. I don't care if it's from the Easter Bunny or Einstein - if I can understand it and not find fault in the evidence, reasoning and logic behind it, I accept until it's been adequately challenged or discredited. I have not seen, in my estimation, these relatively simplistic things explained by the pro-AGW advocates.Moderator Response: [DB] Please, everyone, RW1 has amply demonstrated over many threads and in comments almost beyond number that he's not interested in learning anything here (by his own admission), but only in putting his own brand of logic and and calculus on display. Thank you all for the good faith efforts, but DNFTT. Thanks! -
Bob Lacatena at 12:20 PM on 17 April 2011Clouds provide negative feedback
10, RW1,So, 239 W/m^2 incident on the surface becomes 396 W/m^2 from 157 W/m^2 of 'back radiation' from the atmosphere (239 + 157 = 396).
Where do you get 157 of "back radiation"? Why do you treat the energy absorbed by the atmosphere as absorbed by the surface? Why and how do you use Stefan-Boltzman to compute the component 16.6 W/m2? FYI... These are rhetorical questions. I don't really want to know. Your entire model is invalid. You need to study more, and completely rethink things. There is no 1.6 amplification factor needed to allow an additional 3.7 W/m2 to leave the system. I still have no idea where you got your 16.6, or what you think it means....why doesn't it take 1075 W/m^2 at the surface to allow the 239 W/m^2 from the Sun to leave the system...
You will never get an answer to this question because it is non-sensical. You need to look at things more carefully, probably abandon your current assumptions and perspective, and try to see if you can understand it properly. I suggest starting completely from scratch. I don't think that I can help you. You need an open mind, serious study time with books, and to let go of whatever it is you think that you know. There's a guy over at Nova's loony-bin site who does stuff like you're doing. If you're trying to learn by listening to him, you're only to wind up being get very, very confused. -
WSteven at 12:00 PM on 17 April 2011Debunking Economic Myths from the Climate Hearing
@Mike @Dan Moutal I speak mainly out of frustration as a concerned Canadian. I'm well aware that there are Conservatives/Tories who are trying to make effective environmental change. It's just this "feet-dragging" you mention Dan that gets me. But it is worse than merely "feet dragging", the Harper government is actively promoting Canadian coal and oil in a time when scientists are telling us that we need to wean ourselves off of fossil fuels. The Harper government is also planning expand development of the Tar Sands. I know that they've done some things, but the Conservative Party of Canada still have a long ways to go. I've written a letter to my local MP to remind him that I consider the issue of GHGs to be very important to me this coming election. I hope other Canadians are doing something similar, or better. -
JMurphy at 10:47 AM on 17 April 2011What was it like the last time CO2 levels were this high?
Gilles wrote : "34 : climate has never cooled after Pliocene ?" Oh, is that what you meant ? You are not very clear sometimes and I would suggest that is most of your problem, unfortunately. Your English is good but not as good as you think. -
Dan Moutal at 10:46 AM on 17 April 2011Debunking Economic Myths from the Climate Hearing
@WSteven "I'm sure the Conservative Party of Canada is pretty much the same." Thankfully no. Although many in the Conservative base here in Canada are absolutely in denial, the Conservative party does officially accept climate change. They even stated after climategate that leaked emails are no basis to change their position on the matter. Not bad for a party who just a few years ago was talking about 'so-called greenhouse gases' That is the good news. The bad news is that Canada has been obstructionist on the world stage and has the lowest aspirational GHG targets of any industrialized country. And to make matter worse the official government position is to do nothing until the US does something. -
JMurphy at 10:39 AM on 17 April 2011Video on why record-breaking snow doesn't mean global warming has stopped
batsvensson, firstly you should read more than the title and first line of anything, if you want to find out more information - such as the following paragraph from that link : “Recent increases in the water temperature of the Great Lakes are consistent with global warming,” said Burnett. “Such increases widen the gap between water temperature and air temperature – the ideal condition for snowfall.” I.E. increased temperature leads to increased snowfall. Secondly, you shouldn't rely on outdated ideas, especially since the site I linked to continues : It was no more nor less convincing than anyone else's ideas. At a time when scientists could not explain the observed general circulation of the atmosphere, not even the trade winds, theories about climate change could be little more than an amusement. I.E. things have moved on a bit since then. But you seem to have ignored the UCSUSA link... -
adelady at 10:11 AM on 17 April 2011Last day to vote for Climate Change Communicator of the Year
So when do we get the results? Not that I'm anxious or anything.Response: Not that I'm anxious either but this is what the webpage now says: "The voting period has now closed. We will be announcing the results soon." You can sign up to be notified of the winner. -
Steve Metzler at 09:34 AM on 17 April 2011Venus doesn't have a runaway greenhouse effect
Interesting. I have a lot of respect for Hansen, but having recently finished reading Storms of My Grandchildren... well, I felt he lost the plot a bit with that tacky sci-fi piece at the end where he postulates that Earth will go the way of the runaway greenhouse effect. My money is on a less dramatic but equally ignominious fate for mankind: a doubling of CO2 ca. 2050 causing our major crop producing areas to become severely drought constrained just as the world population is approaching the 9 billion mark. War, greed, and human nature will do the rest. -
Nick Palmer at 09:33 AM on 17 April 2011David Evans' Understanding of the Climate Goes Cold
Lassesson #15 Dana1981 #16 Re: "Even if we stopped emitting all carbon dioxide [...] it would be cooler in 2050 by about 0.015 degrees." Whether he was talking about Australian emissions (which he was) or global emissions, the figure seems wrong. If we stabilise at 390ppm tomorrow, we've still got 30 years warming in the pipeline (takes us to 2041). We're not going to lose 30 years worth of radiative forcing overnight and go back to today's temperatures (minus a little bit) in only 9 years are we? - what about the longer term feedbacks which would be coming into play by then anyway? As I pointed out before, this seems to be a new denier meme popping up all over the place. It basically goes: - there's virtually no point in making a huge effort now because it will have almost no effect. The meme purports "no effect" to mean global temperature being the same or less in 2050. It sneakily ignores that if we do nothing or not much, global temperatures will be up and rising fast in 2050. It looks to me like one of the more outrageous pieces of grossly twisted thinking from the denialist propaganda factory. I liked Spaerica's comment at #7 It's sort of like telling a cancer patient "why bother with chemotherapy, it will only shrink your tumors by 5%" when without chemotherapy the tumors will grow so fast that the patient will be dead within a week. although I think we need a different metaphor for public use. -
bill4344 at 09:22 AM on 17 April 2011Debunking Economic Myths from the Climate Hearing
I still have yet to receive a reply to the following question from any (allegedly) conservative 'skeptic' - 'What is the conservative position on conducting a radical experiment with the one atmosphere we possess?' Real conservatives aren't the problem. It's militant reactionaries we're contending with. -
villabolo at 09:13 AM on 17 April 2011What was it like the last time CO2 levels were this high?
@ Gilles: "as is rather usual in climate discussion, it seems that you would like to live in a world without any problem? without heat wave, crop failures, without poverty, without deaths, without bad trolls on your favorite web site ... I can understand it, but isn't it a little bit ... childish ?" Gilles; I really don't care about the 'trollism'. What I do mind is your seeming lack of understanding of basic AGW points. It is not an issue of whether you agree with those points but rather that you either don't acknowledge them and carry the conversation from there, or that you are actually ignorant of them. That puts us in the exasperating position of having "to spoon feed" you, as Chris G said. As far as living in a world without any problems, the issue is not the usual problems that have been happening in the past but the obvious prospect of severely escalating problems in the future. We're talking about billions of people. Last time we lost 1/4 of our population, throughout Eurasia, it was due to a few rats, and their fleas, per person. Think of how easy it would have been to prevent that. Isn't it childish to engage in magical thinking and wish a thunderstorm away? "One can always do a list of everything that went wrong these last years : what does it prove ? what's the use of all these cherry-picked events ? and what went worse was not that - it was mainly..earthquakes, you know." As far as cherry picking is concerned, Gilles, that is when you take facts out of the context of the big picture in order to give a distorted view of things. On the other hand, highlighting is what you do when you have presented the big picture first and then focus on a fact in context of that picture. One can rarely give the big picture on this subject, in conversations like this. That is due to the enormity of the issues. Yet, you are supposed to know what those issues are in detail if you come to this forum to discuss them. As far as your statement that earthquakes killed more people in the past few years that is both irrelevant and it also qualifies as cherry picking. You are concentrating on a natural event that is sporadic in a given time period versus human distorted 'natural' events which are increasing on a year by year level. Besides, you have not responded to the issue of Arctic Ice cap shrink and its effects in the near future. However that is definitely off topic and should be dealt with elsewhere. So I will briefly steer this wayward thread back into its original course. Compare the Pliocene's arid ecology in North America and please tell me; do you want a bumper crop of corn in Kansas or would you prefer a bumper crop of cactus? Expect that to happen with our business as usual policy within the lifetimes of our grandchildren. -
Alec Cowan at 08:42 AM on 17 April 2011The e-mail 'scandal' travesty in misquoting Trenberth on
@Ken #127 [Thanks DB for letting me know] Do your own calculation on an incremental basis for that 0.9w/m2. This is a reality check for common people, not the substitution of lines of research. You'll get some value along 0.25 to 0.3°C -what is like telling that a grown human is 1 to 2 meters high, bad for being a witness in a trial but good information for an Andromedan-. You can do another reality check by supposing that those, say, 0.3°C will be obtained once and only the 0-100m layer in the oceans has warmed 0.3°C. Suppose a linear process, forget the ice melting, the lands, the atmosphere and 97% of all the ocean, and even suppose that such imbalance will only disappear once the temperature has raise 0.3°C. How many years do you need? 0.03-0.3-3-30-300-3000? Repeat the calculation considering all the oceans. How many years do you need. Start to sensitize the calculation, including continents warming quicker than oceans, more clouds modifying albedo and a lot "details" that are still major contributors to the real situation. What do you obtain? About the programs you need to be payed to download and use for free, here I'm showing some images I got from there (low taste colouring is courtesy of the programming team):My home is 'about' the letter A. One of the problems I proposed is taking those three images for the same month and making a rough estimate of the variation in heat content from one year to the next considering the profile to be the constant from 38 to 42° of latitude (there are more than 2 x 1016 tons of water in that slice). Try yourself and you will be surprised by the results. [The problem of moving downwards the temperature profile goes along with this problem and both have a lot to do with the 'travesty', a legitimate concern expressed by Trenberth and many many more]
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RW1 at 08:40 AM on 17 April 2011Clouds provide negative feedback
Sphaerica (RE: 9) " It takes +16.6 W/m^2 at the surface for a 3 temperature rise. Where are you taking this from?" From the Stefan-Boltzman law. At a temperature of 288K, the surface emits about 390 W/m^2. At a temperature of 291K (+3C), the surface emits 406.6 W/m^2 (+16.6 W/m^2). "Again, where are you getting this math from? Do you have a source, or is it your own inference? [In simple energy balance terms, it takes about 390 W/m^2 at the surface to allow 239 W/m^2 to leave the system...] No. This is a gross oversimplification of the problem, and will lead to errors. It is also flat out incorrect. Notice that the energy entering the system from outside is only 184 W/m2, and only 161 W/m2 of that is absorbed." The total energy entering the surface is 239 W/m^2. Trenberth has 161 W/m^2 coming in directly from the Sun. The remaining 78 W/m^2 from the Sun he designates as absorbed by the atmosphere and brings it to the surface as 'back radiation'. Only it's not really 'back radiation' but 'forward radiation' that last originated from the Sun (as opposed to 'back radiation' as being energy that last originated from the surface). So, 239 W/m^2 incident on the surface becomes 396 W/m^2 from 157 W/m^2 of 'back radiation' from the atmosphere (239 + 157 = 396). -
David Horton at 08:19 AM on 17 April 2011Muller Misinformation #3: Al Gore and polar bears
The obvious question for Muller is "How could a melting, thinning, reducing Arctic Ice Cap NOT have a deleterious effect on Polar Bear populations?" -
Gilles at 08:08 AM on 17 April 2011What was it like the last time CO2 levels were this high?
34 : climate has never cooled after Pliocene ? 35 : I don't think your answer is really one, since world population has increased by several billions - it may BTW be interesting to know that the 30000 deaths have been almost compensated by a corresponding decrease the year after, most of them being old people having shortened their life by a few months. Sad enough, but you don't intend to be immortal do you ? and do you really hope avoiding all this kind of events by reducing FF ? "Uh, CO2 levels went down?" : yes but .. why ? 37 : my point was the rise of temperature didn't prevent population from growing - i did not state that it grew thanks to FF , ( although it is pretty obvious), but that temperature did not prevent it. So my question was : when will it do it ? Now it this OT, you should have said that to Villabolo already at #9 and #31 - why do you notice only my answers ? Concerning Pliocene, I'm far from being an experts, but some googling led me for instance to that : "In addition to the above experiment, several simulations were conducted using increased levels of atmospheric carbon dioxide; higher CO2 amounts have also been proposed as a potential cause of the warmer Pliocene climates (Crowley, 1991). Rind and Chandler, (1991) pointed out that SST patterns such as the one seen in the Pliocene are inconsistent with CO2 generated warming, however, it is possible that some combination of CO2 increase and ocean heat transport change could have resulted in the warmer Pliocene surface temperatures. Figure 3 shows the various levels of ocean heat transport required to generate the PRISM SSTs given various atmospheric CO2 increases. The graph indicates that with modern ocean heat transports (0% increase) CO2 levels must have been at least 1400 ppm (4.5 times the modern value) in order to generate the global warming of the Pliocene. So far, estimates based on carbon isotope measurements by Raymo and Rau (1992) suggest that Pliocene CO2 levels were, at most, 100 ppm greater than today." well, I don't know if they're right, but it seems that they claim that CO2 is responsible only of 10 % of the warming or so (much in line with what I explained on feedbacks :) at least it is a possibility , which means that it is by no way granted that it makes sense to compare CO2 levels and temperatures to current ones. Comments ?Moderator Response: [Muoncounter] An astonishing reply, Gilles, even for one with your track record. Heat wave deaths among the elderly are 'compensated' for the following year? Nice compassionate worldview you have. -
villabolo at 08:06 AM on 17 April 2011What was it like the last time CO2 levels were this high?
@33 Gilles: "would survive what ?" Gilles, you do amaze me. To your first question as to what humanity would survive (give me some time to chuckle) he simple answer was given when I described Lovelock as a believer (Me too) of CAGW. Spelled out that means "Catastrophic Anthropogenic Global Warming" No, I'm not one for meticulous and mathematical details but I'll throw this in. 10 degrees Fahrenheit above pre-industrial levels. I seriously don't think that this civilization will not go over 600 ppm because economic downturn/collapse (sometime before we reach 600 ppm) brings our consumption spiralling down. That may not be enough for a 10F increase but then there are pesky things like the Siberian permafrost/defrost. Please see video below. "http://www.youtube.com/watch?v=vSLHvZnbYwc&feature=related "As far as I know, the huge increase of population is correlated with an increase of FF consumption and an increase of temperature - so if any, the "negative" influence of increasing temperature has been largely offset by the positive effect of energy availability - or the huge modern demographic growth would be totally incomprehensible." Gilles, it's the use of FF that is digging our graves. Incomprehensibility of population growth is irrelevant. I know it is due to Carl Bosch developing the conversion of natural gas to synthetic fertilizers in 1913. So what? To use an analogy, you can grow fat on junk food; then you die. As for negative effects being counterbalanced by "positive" effects, tell that to the Egyptians who pay 40% of their salaries for staple foods. Let's connect the dots. There have been multiple crop failures throughout the world causing a spiraling in grain prices. Winter/Summer of 2010/2011: a. Russia/Ukraine: Up to 40% failure of wheat crop due to severe drought and high temperatures. They are major wheat exporters. b. Pakistan: 20% of its land inundated by floods. They had to import food. c. Australia: Major damage to wheat crops due to intense rains (from warming oceans). They are a major wheat exporting nation. d. Argentina: Soybean and corn crop loss due to drought. e. Canada: Damage to wheat crop due to intense rains. They too, are a major wheat exporting nation. f. China: Loss of almost the entire winter wheat crop. Neither an exporter or importer of wheat, China has been self sufficient in that crop. Not that it matters because they have a huge population that will need to import grains. g. Mexico: Major loss of corn crop. They have had to import 50% more corn from the US than previously. No; it's not the individual crop failures that can be pinned to AGW; it's the number and frequency. Expect more of he same throughout the rest of this decade. It's up to you to calculate the "negative" effects (quote marks yours). Now please give me a simple argument to tell me when the negative effect of an increase of temperature would be much larger that the positive effect of increasing energy consumption -and conversely the positive effect of avoiding the increase of temperature would be much larger that the negative effect of suppressing 80 % of the energy consumption- since the whole history demonstrates exactly the opposite ?" [Underlining mine] "It's this simple, Gilles. It's already happening. Furthermore, your concept of the "positive" effects of FF, irrespective of the AGW issue, is questionable; but that's another story. As far as the negative effect of decreasing our consumption of FF by 80%, I am of the opinion that we have to cut our consumption by 90% within the next 10 years. That is enough to make some of the forum members here gulp. Of course, 'Skeptics' will get a hernia (due to intense laughter) when they hear that. But this is how I perceive the situation. If we take the "extreme" measure of reducing FF consumption by 90% in the next decade, then we will get our teeth kicked in by AGW. No ifs, ands or buts. This will be, in major part, due to the Arctic Ice Cap shrinkage and its drastic effects on our climate in the Northern Hemisphere. This will include the acceleration of the Siberianpermadefrost, and the subsequent increase in the metabolism of the methanogens that are releasing ... methane. Positive feedback, you know. It's too late to stop that IMO. The Arctic Ice Cap went past the tipping point long ago. Those who say otherwise are probably not taking the 1F of increased heat that we're due in the next 30 years. That assumes that we magically stop all FF emissions cold and right this minute. Thermal lag you know. However, if we don't take the drastic actions I've proposed or we take symbolic and token actions (as I predict will happen by decade's end) then we're going to get our teeth kicked in and, a few decades down the road, our skulls bashed in. Nice choice, isn't it? Bottom line, Gilles, you don't calculate and scratch your head when it's time to slam the brakes. I hope this answer has been simple enough. I'm sure I forgot a few things, however. -
Bob Lacatena at 07:07 AM on 17 April 2011What was it like the last time CO2 levels were this high?
33, Gilles,Really? why has it cooled meanwhile, then ?
If you need to ask this, then you have some studying to do.As far as I know, the huge increase of population is correlated with an increase of FF consumption and an increase of temperature...
One upon a time, my own height was well correlated with my age. As I aged, I grew. I should probably be about 100ft tall by now....please give me a simple argument to tell me when the negative effect of an increase of temperature would be much larger...
Because extreme increases in temperature will result in major desertification and other ecosystem changes, as well as the alteration of climate zones (i.e. growing seasons). More importantly, major changes in precipitation patterns and large, difficult to endure droughts will greatly reduce crop productivity, leading to widespread famine. It certainly won't help, either, when the productivity of the ocean as a food source plummets because of acidification. This will probably take 50 to 100 years, but once it starts, there will be no going back. This is the game that you are so callously playing with civilization. Now can you please go back to the topic, instead of dragging the thread into your own personal conversation about whatever you want to talk about? -
Chris G at 07:05 AM on 17 April 2011What was it like the last time CO2 levels were this high?
Here as an interesting article along the same lines where Csank was a co-author, Significantly warmer Arctic surface temperatures during the Pliocene indicated by multiple independent proxies (No pay wall) Gilles, Re: "Really? why has it cooled meanwhile, then ? " Uh, CO2 levels went down? What makes you think that the planet will behave differently now than it has under similar conditions in the past? You are asking us to spoon feed you information that you can readily look up yourself. Examples: Damaging effects ocean+acidification Hadley+Cell heat+crop+production (The one on plant stress is very pertinent.) Or, maybe you should examine the links between the Russian heat wave last year and unrest in the Middle East this year. Hint: Where did Russia used to sell a lot of wheat in prior years? What causes CO2 levels to change and how does that affect the climate? You are diverging from a reasonable argument with holes in it into something else. You have asked repeatedly what, other than man, causes changes in CO2 levels, and repeatedly you been directed how to find that information. Please quit asking the same question. Yes, quantitative, that is what this article and others like it are about. Sometimes I find this useful: Rational Discussion Rules -
Bob Lacatena at 06:43 AM on 17 April 2011Clouds provide negative feedback
7, RW1,...the data doesn't conclusively show that on average they trap more energy than reflect away...
What data? Again, citation please. Although, I'd point out that as with everything, the climate has barely begun to reflect the changes. We haven't come close to doubling CO2 yet, and we've only seen half of the 1.4˚C of warming to which we've already committed. So the data isn't very likely to conclusively show anything, but that hardly makes it an argument that something is wrong.It takes +16.6 W/m^2 at the surface for a 3 temperature rise.
Where are you taking this from?...the system gain or system amplification...
You're an electrical engineer....which is a factor of about 1.6 (390 W/m^2/239 W/m^2)
Again, where are you getting this math from? Do you have a source, or is it your own inference?In simple energy balance terms, it takes about 390 W/m^2 at the surface to allow 239 W/m^2 to leave the system...
No. This is a gross oversimplification of the problem, and will lead to errors. It is also flat out incorrect. Study this:Notice that the energy entering the system from outside is only 184 W/m2, and only 161 W/m2 of that is absorbed.
In short, if it is going to take an additional 16.6 W/m^2 to allow 3.7 W/m^2 to leave the system to restore equilibrium, then why doesn't it take 1075 W/m^2 at the surface to allow the 239 W/m^2 from the Sun to leave the system at initial equilibrium (16.6/3.7 = 4.5; 1075/239 = 4.5)???
Because your premise, that "it will take an additional 16.6 W/m2..." is incorrect.Moderator Response: [muoncounter] This gain theory/calculation was discussed in excruciating detail on Lindzen and Choi find low sensitivity. Please do not restart it here. -
windbarb at 06:36 AM on 17 April 2011Muller Misinformation #3: Al Gore and polar bears
Enginerd raises a really important point. At what point is the defamation and fraud of the false claims (Muller's, Christy's, and the twisted words from Climategate, just to name a few) legally actionable? If it was actionable, who would be the complainant? And how can universities who employ those who misrepresent facts so blatantly continue to employ them? (Moderators, I understand that this might be a tangent that belongs on another thread.) -
muoncounter at 06:25 AM on 17 April 2011What was it like the last time CO2 levels were this high?
Gilles#33: "the huge increase of population is correlated with an increase of FF consumption and an increase of temperature" Ah, the good old correlation equals causation game. We can use that now? "please give me a simple argument to tell me when the negative effect of an increase of temperature would be much larger that the positive effect of increasing energy consumption" Apparently you missed the more than 30000 deaths during the European heat wave of 2003? Odd that a society so rich in the positive effects of energy consumption would suffer so much hardship during a mere localized heat wave. Firefighters know this to be true: “It is easier to stay warm than it is to stay cool in all this gear,” he said. “Once you get overheated, it is really hard to get cooled off. You have to be out in the cold like this a long time before it will affect you systemically, whereas in the heat like that, in 15 or 20 minutes, guys start dropping if you don’t rehab them.”Moderator Response: Gilles, a more relevant thread for your claims is "It's Not Bad." -
batsvensson at 06:10 AM on 17 April 2011Video on why record-breaking snow doesn't mean global warming has stopped
What led you to such understanding ? "In 1937 [Sir George Clarke Simpson] suggested that, paradoxically, an increase of solar radiation might bring on an ice age." -
batsvensson at 06:09 AM on 17 April 2011Video on why record-breaking snow doesn't mean global warming has stopped
Global Warming Means More Snow For Great Lakes Region ScienceDaily (Nov. 6, 2003) — Global warming has had a surprising That is not a prediction JMurphy -
JMurphy at 05:55 AM on 17 April 2011What was it like the last time CO2 levels were this high?
Gilles wrote : "Really? why has it cooled meanwhile, then ?" What has cooled, and since when ? -
Tor B at 05:35 AM on 17 April 2011Muller Misinformation #3: Al Gore and polar bears
To see video evidence of drowned polar bear cubs associated with Global Warming related retreating sea ice, see this PBS footage. It's just two and a half minutes long. -
Gilles at 05:32 AM on 17 April 2011What was it like the last time CO2 levels were this high?
ChrisG : "In the Pliocene, the position of the continents, the output from the sun, and the orbital mechanics are largely the same as they are now; so, we should expect a similar thermodynamic equilibrium from a similar atmospheric composition." Really? why has it cooled meanwhile, then ? Villabolo : "Gilles, oh Gilles. Please keep in mind that there is a difference between humanity per se and civilization. James Lovelock, author of the Gaia Hypothesis and believer in CAGW, says that as little as 100 million human beings would survive." would survive what ? As far as I know, the huge increase of population is correlated with an increase of FF consumption and an increase of temperature - so if any, the "negative" influence of increasing temperature has been largely offset by the positive effect of energy availability - or the huge modern demographic growth would be totally incomprehensible. Now please give me a simple argument to tell me when the negative effect of an increase of temperature would be much larger that the positive effect of increasing energy consumption -and conversely the positive effect of avoiding the increase of temperature would be much larger that the negative effect of suppressing 80 % of the energy consumption- since the whole history demonstrates exactly the opposite ? DM : I am completely ready to admit that CO2 contributes to warm the atmosphere , on very simple arguments of radiative transfer. My only questions are quantitative.Moderator Response: [Dikran Marsupial] If your questions about CO2 as a greenhouse gas are quantitative, then there are a variety of threads here that examine climate sensitivity. There are many knowledgeable contributors here who I am sure would be happy to discuss quantitative issues with you there. If you are not happy with GCMs, you might want to look at earlier work by Gilbert Plass performed back in the 1950s and getting a result in the same ball park as today's GCMs (see RC article for caveats). -
RW1 at 04:42 AM on 17 April 2011Clouds provide negative feedback
Sphaerica (RE: 6), When there is a radiative imbalance, i.e. from additional CO2 added to the atmosphere which redirects more outgoing surface radiation back toward the surface, there is reduction in the amount of LW radiation leaving at the top of the atmosphere (more radiation is arriving from the Sun than is leaving at the top of the atmosphere). To achieve equilibrium, the system warms up until it again radiates the same amount of energy as is arriving from the Sun. To give a numerical example, there is about 239 W/m^2 arriving post albedo from the Sun and 239 W/m^2 leaving at the top of the atmosphere. This represents the system in equilibrium (energy in = energy out). If there was a radiative imbalance (or 'radiative forcing') of say 3.7 W/m^2 from a doubling of CO2, the energy leaving at the top of the atmosphere would reduce by 3.7 W/m^2 to 235.3 W/m^2. Currently, there is about 390 W/m^2 emitted by the surface. In this example, an additional 3.7 W/m^2 is received by the surface for a total of 393.7 W/m^2. The +3.7 W/m^2 is responded to the same as the 239 W/m^2 arriving from the Sun and will be amplified by a factor of about 1.6 (390/240 = 1.6), as this is the measurement of the surface response to incident energy. 3.7 W/m^2 x 1.6 = 6 W/m^2 to allow an additional 3.7 W/m^2 to leave the system to restore equilibrium (239 W/m^2 in and out). The new surface emitted radiation would be 396 W/m^2 (390 W/m^2 + 6 W/m^2), which corresponds to about a 1 C rise in temperature. Does this explain it better? -
Dikran Marsupial at 04:33 AM on 17 April 2011What was it like the last time CO2 levels were this high?
Giles@28 It is not as simple as whether CO2 is a control or a response. It is one part of the wider climate system, and it both influences responds to the other components, generally CO2 tends to respond rather than to initiate; but there have been occasions when CO2 has driven climate change. For instance the emergence from the Snowball Earth is hard to explain without the accumulated CO2 emissions from volcanic activity. The position of the continents can also affect climate by changing rates of chemical weathering (hence changing CO2 levels), which is an example of CO2 initiating a change in climate. I remember reading an interesting paper in Nature about a period of cooling caused by increased weathering as a result of the uplift of the Appalacians (sorry can't find reference at the moment). The Carbon cycle is the key mechanism that has stabilised the Earths climate for millions of years (see this paper). Personally I think calling it a "control" is only really meaningful in a post-industrial setting, because anthropogenic emissions now control the level of CO2 in the atmosphere and hence have a major influence on the climate. Prior to that, the natural carbon cycle acts much more like a thermostat (see Archer book). As to what caused the Pliocene warm period, I don't know, it seems to me unlikely we will even "know" what caused particular paleoclimate events. However, I don't really see the relevance to the discussion. CO2 is a greenhouse gas; its effect on climate is the same, regardless of what caused it to be in the atmosphere. For modern climate, it doesn't matter if the natural response of CO2 to "other causes" is linear or not (I assume you mean natural causes), as we know that the post-industrial rise in CO2 is not a natural phenomenon. This is one of the few things in climatology that we can be sure of. We have circumvented the "natural response" with anthropogenic emissions. -
RW1 at 04:32 AM on 17 April 2011Clouds provide negative feedback
Sphaerica (RE: 6), "Citation please" The albedo effect and global warming "Your assumption, however, that clouds must increase albedo is false. Again, read the above post, and other material. Clouds at high altitudes, which are expected to increase with warming, are composed of ice rather than water. These clouds are virtually transparent to visible light and so do not change the earth's albedo. They do, however, absorb in the infrared and so (as does all H2O) act as powerful greenhouse gases (even though they're solid, not gaseous). Similarly, lower (non-ice) clouds at night will trap heat without changing the albedo at all, so timing of development/dissipation is a factor. Along those same lines, clouds in winter (when the angle of incidence is already low, and the surface being shielded by the clouds is likely snow covered) will have no net change (or even a positive change!) in albedo, while still exhibiting GHG effects. So the assumption that clouds will increase albedo is based on an oversimplification which requires considerably more thought, research and observation." My assumption is not that clouds must increase albedo. The point is if clouds operate as a net positive feedback as claimed, and the data doesn't conclusively show that on average they trap more energy than reflect away, the only way clouds could operate as a net positive feedback is through a reduced albedo, which hasn't happened. I am also aware of the various types of clouds and the complexities of each as it relates to potential changes in the energy balance. " ...is to become 16.6 W/m^2 largely through positive cloud feedbacks... Citation, please. I don't know why you say this. If by 3.7 W/m2 you mean the effect of doubling CO2, then with a climate sensitivity of 3˚C (which is the current best estimate), that would translate into 3.7*3 = 11.1 W/m2, not 16.6 W/m2." It takes +16.6 W/m^2 at the surface for a 3 temperature rise. The 3.7 W/m^2 from 2xCO2 is the additional incident energy at the surface. This is then subject to the system gain or system amplification, which is a factor of about 1.6 (390 W/m^2/239 W/m^2). 3.7 W/m^2 x 1.6 = 6 W/m^2, which BTW, is how they are coming up with a 1 C intrinsic rise from 2xCO2, because +6 W/m^2 = +1C from the Stefan-Boltzman law. "...then why doesn't it take more like 1075 W/m^2 ... Your equations are wrong. You are comparing the wrong factors. The equilibrium temperature of a body is that at which it emits the same amount as is being absorbed. Basically, the equilibrium temperature of the earth would be that at which it emits the same amount of energy as absorbed (i.e. absorbs 239 W/m2, then emits 239 W/m2)." I'm aware of this. In simple energy balance terms, it takes about 390 W/m^2 at the surface to allow 239 W/m^2 to leave the system, offsetting the 239 W/m^2 coming in from the Sun. This is the system measured amplification factor of only about 1.6 to surface incident energy. The AGW claim of a 3 rise requires an amplification factor of 4.5 to allow and additional 3.7 W/m^2 incident on the surface to leave the system to restore equilibrium (239 W/m^2 in and out). In short, if it is going to take an additional 16.6 W/m^2 to allow 3.7 W/m^2 to leave the system to restore equilibrium, then why doesn't it take 1075 W/m^2 at the surface to allow the 239 W/m^2 from the Sun to leave the system at initial equilibrium (16.6/3.7 = 4.5; 1075/239 = 4.5)??? -
grypo at 04:32 AM on 17 April 2011Muller Misinformation #3: Al Gore and polar bears
Where does this story get its roots from? It seems so detailed that you'd Muller would have gotten it from somewhere. -
villabolo at 04:26 AM on 17 April 2011What was it like the last time CO2 levels were this high?
@11 Gilles: "Two questions : a) what is the warming rate which mankind is supposed to be unable to adapt ?" Gilles, oh Gilles. Please keep in mind that there is a difference between humanity per se and civilization. James Lovelock, author of the Gaia Hypothesis and believer in CAGW, says that as little as 100 million human beings would survive. It's even possible to say that (micro) civilizations could exist under the condition he foresees. You only need a few tens of thousands to fulfill the definition of civilization. So would you please rephrase your question based on the potential numbers of a reduced population? Even that would be a silly question to ask; a worthy one but silly nonetheless, due to the enormous difficulty (impossibility?) of calculating the techno-social effects on humanity based on X rate of warming. Human beings are much more difficult to predict than warming rates. That's due to psychology, stupidity and (panic based) ingenuity. I hope you're young. You'll get at least part of the answer to your question(s) without any math or even science. Live long and... -
JMurphy at 04:18 AM on 17 April 2011Video on why record-breaking snow doesn't mean global warming has stopped
batsvensson wrote : "Is that correctly understood?" Not by me, anyway. What led you to such understanding ? -
Dan Moutal at 04:17 AM on 17 April 2011How I lived through a carbon tax and survived to tell the tale
@ Gilles Please go back and re-read my comments, I never said China didn't need the power plants they are building or that there is a significant risk that we can't switch away from FF. But we are getting off topic. It seems that you have already agreed that a carbon tax can work to reduce emissions. That was the whole point of this post. Obviously selling people on short term pain for long-term gain is difficult. No argument from me there. But arguing over The exact details of how large a carbon tax should be, how fast it should ramp up are beyond both of us (neither of us have working economic models at hand). I just pointed to some research done by an economist who spends his time thinking about these issues. If you have links to research that comes to a dramatically different answer then I would be happy to look at them. Otherwise there is not much lest to discuss. -
Chris G at 04:15 AM on 17 April 2011What was it like the last time CO2 levels were this high?
Spike25, I would say that the Csank article above is in the same line as earlier Tripati work, but that is not surprising since Tripati is one of the 'et al' authors. Gilles, I think you should step back and model this as a kind of multi-body problem; whenever one thing changes, all things change. The physics which are used to determine that CO2 is a GHG are well understood. More CO2 causes a warming, but it is not the only thing affecting the climate and humans are not the only thing affecting CO2. How much carbon is sequestered is partly a function of climate conditions, but also continental plate subduction plays a role, etc. However, our production of CO2 through industrial (including agriculture) processes is they only thing that has changed significantly in the last 100 years or so. We know it is getting warmer, and that it will continue to do so; the discussion is about how much and how fast. Feedbacks are everything, and the indication from the above article and others is that the feedbacks will largely amplify the base CO2 effect. Climate models predict this, but we know that climate models are incomplete. That is the nature of models. However, the article above is about the system itself, which by definition has all feedbacks in place and fully accounted for. In the Pliocene, the position of the continents, the output from the sun, and the orbital mechanics are largely the same as they are now; so, we should expect a similar thermodynamic equilibrium from a similar atmospheric composition. I also highly recommend Archer's book "Global Warming: Understanding the Forecast". It covers the basics from the interaction of IR with CO2 molecules on up, but it is not too technical for someone with the skills you have demonstrated. I suspect you are just missing a piece or two of the puzzle and that is skewing your understanding. -
jorgepeine at 04:00 AM on 17 April 2011Muller Misinformation #3: Al Gore and polar bears
thanks for this very interesting post. it shows how denials operate. I am really surprised at how these people (also Monckton) get audience ... -
JMurphy at 03:59 AM on 17 April 2011Christy Crock #3: Internal Variability
Re : the NIPCC. It was set up by Fred Singer and his SEPP organisation (who also dismiss the risks of smoking and ozone delpetion), and backed by the Heartland Institute. Biased, much ? Appeals to those of a certain political persuasion, perhaps ? Trustworthy ? (The answer to the last is 'NO') -
batsvensson at 03:59 AM on 17 April 2011Video on why record-breaking snow doesn't mean global warming has stopped
Hence, when temperature increase snowfall will increase around the polar region causing a greater reflective surface and possible off set any further increase in temperature which in turn may trigger and ice age. Is that correctly understood? -
batsvensson at 03:50 AM on 17 April 2011What was it like the last time CO2 levels were this high?
"Earth's past history is sending us a strong message" The OP is claiming this as a fact while it is an interpretation of earth's history. What reason do the OP think is talking against this interpretation and why should they be ignored?Moderator Response: [DB] Could you rephrase your question a bit more clearly? As written, it is a bit difficult to parse. -
michael sweet at 03:38 AM on 17 April 2011Muller Misinformation #3: Al Gore and polar bears
Dr Muller must have missed this newspaper article about a polar bear who swam hundreds of miles looking for ice, and food. The cub disappeared, presumably drowned. -
Bob Lacatena at 03:30 AM on 17 April 2011Clouds provide negative feedback
RW1,...if the albedo is NOT decreasing (or has even slightly increased)
Citation please. Otherwise either case is speculation. Albedo changes due to ice cover change will be measurable and predictable (in extent and effect, if not rate of arrival). Albedo changes due to cloud cover changes to my knowledge are uncertain at best. We'd know more if certain satellites (DSCVR) hadn't been mothballed, or others lost at launch, or unbuilt satellites had been built, but barring all that... all you have is speculation. Your assumption, however, that clouds must increase albedo is false. Again, read the above post, and other material. Clouds at high altitudes, which are expected to increase with warming, are composed of ice rather than water. These clouds are virtually transparent to visible light and so do not change the earth's albedo. They do, however, absorb in the infrared and so (as does all H2O) act as powerful greenhouse gases (even though they're solid, not gaseous). Similarly, lower (non-ice) clouds at night will trap heat without changing the albedo at all, so timing of development/dissipation is a factor. Along those same lines, clouds in winter (when the angle of incidence is already low, and the surface being shielded by the clouds is likely snow covered) will have no net change (or even a positive change!) in albedo, while still exhibiting GHG effects. So the assumption that clouds will increase albedo is based on an oversimplification which requires considerably more thought, research and observation....is to become 16.6 W/m^2 largely through positive cloud feedbacks...
Citation, please. I don't know why you say this. If by 3.7 W/m2 you mean the effect of doubling CO2, then with a climate sensitivity of 3˚C (which is the current best estimate), that would translate into 3.7*3 = 11.1 W/m2, not 16.6 W/m2....then why doesn't it take more like 1075 W/m^2 ...
Your equations are wrong. You are comparing the wrong factors. The equilibrium temperature of a body is that at which it emits the same amount as is being absorbed. Basically, the equilibrium temperature of the earth would be that at which it emits the same amount of energy as absorbed (i.e. absorbs 239 W/m2, then emits 239 W/m2). If CO2 adds the equivalent of 3.7 W/m2, then the total amount absorbed by the climate system becomes 239 W/m2 + 3.7 W/m2 = 242.7 W/m2. With expected feedbacks, this would be 239 W/m2 + 11.1 W/m2 = 250.1 W/m2. The question is, what surface temperature (actually, combined ocean/surface/atmospheric temperatures) results in this amount of emission (radiation)? The answer is a total of 3˚C....where is all the energy coming from that is supposed to be causing the enhanced warming? Outside of the above discussion, I think a major mistake that you may be making (this is a guess) is to equate water vapor feedback with clouds. While increased water vapor could result in more clouds, this is not necessarily the case, and clouds are not the form in which the main feedback would occur. Increased temperatures would increase the specific humidity... the amount of moisture carried in the air not in the form of clouds (condensation). This would be a proportional increase for every cubic meter of atmosphere, and H2O is a very powerful greenhouse gas. This would be the main contributor -- water vapor -- to positive feedbacks. Other positive feedbacks would include clouds (of different sorts), reduced snow and ice, natural release of CO2 and CH4, as well as others. All total, these would result in 3˚C of warming per doubling of CO2. -
Gilles at 03:11 AM on 17 April 2011What was it like the last time CO2 levels were this high?
Do you mean that there can be spontaneous variability in the CO2/temperature/oceans system even without a injection of CO2 ? interesting -I thought it was impossible. Nevertheless , unless you justify that the warm period in Pliocen was triggered by massive injection of CO2 from volcanic activity, it corresponds to what I'm saying, CO2 is a response, not a driver. The fact that it enters a feedback loop doesn't change the situation, because amplification acts on both - CO2 and temperature - and so conserve the initial ratio. { - snip - long-winded, off-topic overly mathematical derivation of feedback removed - } In other words, if the amplification factor is *not* large, the CO2 responds only linearly to the "other causes" and its relative part in the global temperature change is minor. I know perfectly that you think it is not the case - but that the amplification factor is large and that CO2 plays a major role - but I haven't seen yet a decisive evidence for that, and I like more explanations to justifiy it.Moderator Response: [muoncounter] Variability of atmospheric CO2 in geologic history is the subject of numerous other threads. Before you continue theorizing, please familiarize yourself with some basic tenets of geologic processes.Your other points(?) are addressed in several sensitivity threads. Rather than merely calling for others to bring you evidence, you might consider engaging in some actual research of your own.
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