Why Has Global Warming Paused? - William Happer

so our last speaker for today's session will be will hopper will was born in India in 1939 and spent a number of his early years there after returning to the United States he was educated at the University of North Carolina and Princeton University where he received his PhD in 1964 after holding several other positions will and served on the faculty of Princeton since 1980 except for two years as head of the office of science of the US Department of Energy about 20 years ago currently he's the Cyrus vote bracket professor of physics at Princeton his interests have been primarily in atomic physics optics and spectroscopy much of his work involves spin-polarized items in nuclei and a wide range of applications for medical imaging to atomic clocks adaptive optics and fundamental tests of physical laws well as the recipient of numerous awards including the Humboldt Prize the broader prize the Davidson Germer prize in the Thomas Alva Edison patent orde his title today is tell us why is global warming paused well thank you very much and where is the guest of honor like I need to be able to see him oh there you'll see why in just a bit okay so this is the title why has global warming told many of you perhaps don't realise that we have in our midst Freeman Dyson the climate scientist and this is the title of a book that was published in 1982 and there he is Freeman Dyson and it's called the long-term impacts of increasing atmospheric carbon dioxide levels so we'll come back to that in a minute but Freeman has a long interest in climate and but here's he has a rival the Al Gore is also interested in climate L actually has a nobel-prize Freeman maybe you maybe is there still a lot of time anyway this is a cover of elves most recent book you note I've got a copy of it here from the Princeton University Library it's quite impressive glossy and this cover was taken from as Al says from a NASA satellite picture so it's the real earth it's had a few embellishments let me show you the original which I looked up ok this is original actually there are a number of differences that if you look closely for first of all there are lots more clouds on the original then on the cover of the book you know you wouldn't want to confuse people with clouds right here's the Sun beaming down from there you know you can see all this open water here on the North Pole and the original it's actually not there a minor detail let's go on but the book actually has the cut there are two parts to the cover this is the cover and then if you open it up you can see what happens to the earth because of the increases of carbon dioxide so I'll show you the that here and so these are the effects of continuing to emit co2 it's really quite alarming you know the the Arctic Ocean kind of looks like the Caribbean you know the Greenland ice is all melted here's a big bay here that's filled with seawater for some reason the ice around it is perfectly fine the ice is OK in Iceland but the most alarming thing to me you know as a physicist is somehow the law of angular momentum has been repealed this hurricane is rotating the wrong direction and here's another one it's rotating the right direction but it's on the equator yeah those of you know about hurricanes the reason they rotate is because of the Coriolis force of the rotating nurse' you know there is no Coriolis force on the equator so no one has ever seen a hurricane on the equator ever it doesn't happen but uh maybe it will you know I won't mind I don't have a Nobel Prize well when I was preparing this I was trying to find who had actually taken the photograph so one of Freeman's friends and one of mine - I'm glad to say is the astronauts Harrison Schmitt who after retiring from being an astronaut was senator from New Mexico for a while and when I was corresponding with him he said please wish Freeman a happy 90th birthday for me we met many years ago when I visited Princeton I've been an admirer for many reasons from astrophysics to strategic defence to issues with climate modelling and then we got to talking about this photograph he said this is a photograph I took it's from my camera so this is directly from his camera and he says well if you look at this solution maybe you can't see it but it's of the South Indian Ocean and it's a full picture of the globe you know by good luck he took the photo when the Sun was shining on everything below him so I wrote him and I said did you wait until you got just the right lighting to take the photo he says no we were just busy and this was the first chance I got to shoot the picture so anyway here's the exchange it's very very interesting exchange to talk to someone who was actually been there and he was kind enough to say I'm going to send you a present for Freeman and arrived this morning by FedEx how can somebody turn on this uh so I'm going to show you the gift from there it is so Freeman I'm Harrison Schmitt and here's the photograph and there there's a note for you to which I did not open alright so uh back to the earth it really is a beautiful place isn't it the earth blue wonderful plows of course the clouds keep us cool you know if you change the clouds that's like just amount it has a huge effect on warming or cooling come back to that so what's all the fuss about we're talking about the effects of increasing carbon dioxide so this scale on the right is the atmospheric carbon dioxide it parts-per-million up to about your 2012 we've just crossed 4,000 2013 this is measurements taken at Mauna Olu ah it's a wonderful work done by Keeling a real hero in this field and it's steadily going up there little blips and when we have economic recessions and the the oscillations up and down or summer and winter you know when the summer comes the northern forests suck co2 out of the air and so the co2 levels dropped rapidly during the summer and early fall and then they recover during the winter and early spring so up down up down these are huge oscillations if you measure up barrel Alaska or somewhere like that and here here is the earth's temperature from Hadley the British sight but all temperature records look much the same nowadays and you can see there's not a whole lot of correspondence between the temperature it's been quite flat if anything going down slightly for the last 15 years since 1998 was a big El Nino year this spike and then there's some down years here due to volcanoes in the in the Philippines amid members a period of cooling from up to 1980 75 or 80 or so down here is one of the possible other correlations besides co2 and this is the phase of the Pacific decadal oscillation which actually fits quite a lot better I don't know co2 it's not bad for the cost of a first stamp first-class stamp but it's not terribly good for for temperature well everybody I mentioned everybody gets the same result this is from NOAA you can see the last 10 years there has been no change in temperature it's the ocean land you know and the people were beginning to notice this is one of the first things I saw in print this was from Der Spiegel earlier this year in January and the title says for sure Rhett's anubis do stunts buy out available so researchers are scratching their head about the pawls in the in global warming which is the title of my talk today you know so what we're looking at here is year the bars here with error bars black points are measured temperature and and the various colors are predictions from IPCC okay so not too good all right well you might say well that's their Spiegel well this came out in nature last week so this is you can look it up Nature climate change and so what I'm showing you here is the results of models of what the temperature rise for decades should be and sin degree centigrade for a decade compared with these red bars or what's actually observed ok so there's many many different models big expensive computers all over the world and so the the the last year is from 1993 to 2012 the right is 1998 to 212 so there is a 20 year interval the last 10 year interval - it's worse on the last 10 years it's getting worse with time but here's I here's Freeman's prediction from the book I just showed you so we were pretty good you know right in the middle of the pack you know so anyone who says that Freeman is a contrarian is completely wrong he was as wrong as anyone else but I was there with you Freeman so I share some of the blame all right so so something is seriously wrong with the models all right let's talk about what it might be so let me review for you a little bit about the basic physics of the earth's temperature we were course warmed by the Sun if it weren't for the Sun we have graphically cooled down - uh horribly cold temperatures about 70% of the Sun makes it to the surface of the earth because some is reflected by clouds some by Rayleigh scattering the beautiful blue light of the of the sky and some is actually reflected by the surface instead of turned into heat so roughly 70% makes it down here then the earth has to get rid of the heat or else the surface would warm up and it gets rid of that in a much more complicated way close to the ground most of the heat is carried away by convection because if you put in the numbers there's no way you can radiate enough and keep the atmosphere stable so there's a convective layer about 10 kilometers thick the troposphere where most of the energy of the hot surface is being carried up by churning air parcels mostly water vapor condensing often and when it gets high enough it's able to be released to space and a very tiny amount on very clear parts of the earth actually can Riggi directly into space and that's where many of the alarmist models are focused on this almost trivial amount of the cooling that's there okay this is quite accurate from NASA some things that I need to remind you who or not don't live and breathe this stuff all the time is if you look at the structure of the Earth's atmosphere the first 10 kilometers are the troposphere this region I told you where the air is turning round and round and carrying heat up and when it gets to about 10 kilometers there's enough radiative clarity that it can radiate the heat and from then on there's no more turning and we're in the stratosphere and from the stratosphere on up the loss of heat it's entirely by radiation of infrared as a result of this chaining a churning motion here the troposphere is roughly isentropic so the entropy per kilogram is the same at the ground level as it is at 10 kilometers because the expansion of the air cools it enough to keep the entropy per kilogram constant that's what you would expect for a convective process that's what you measure okay well I mentioned atmospheric motions and so this is a nice picture that least gives you the rough idea of how the earth earth works the Sun is hottest along the equator and so there's a lot of heat to remove at the equator and that is called the equatorial convergence zone and this is a region of very severe thunderstorms lots and lots of rising hot air and part of it heads north raining out you know lots of water in the process part of it go cells these are the Hadley cells these fall down to the earth at about 30 degrees you see that's northern New Mexico the Chihuahuan Desert over in Europe it's the Sahara Desert so these descending cells are bands of desert around the earth there are similar ones on the south and then there's a couple of more cells there and as of this circulation at least if the law of conservation of angular momentum continues to hold the the this returning air coming from mid-latitudes toward the equator is thrown eastward this makes the Tradewinds the important trade winds that were so important to the settlement of the Americas and the trading ships relied on wind and the north as it moves north the same conservation of energy gives us the westerly so we have easterlies near the equator westerlies in the temperate zones and pretty complicated stuff up near the poles but anyway you have to keep that picture in mind if it's not familiar already well ok how we've talked about radiation there's only one way to cool the earth to space and that's radiation you know that and so the earth is absorbing sunlight which is this red curve here sun is a little under 6,000 degrees 55 kelvin blackbody here not all of that radiation gets to the surface because there's absorption by overtones of water here there's a lot of Rayleigh scattering the blue sky light that we see here but seventy percent roughly gets to the surface and then the surface has to reradiates at and if the surface tries to reradiating to space it has the problem that it can't get through the atmosphere because the atmosphere is full of gases that absorb infrared radiation so here the actual components water is by far the most important you can see the absorption bands of water this is C this is the attenuation probability between the ground to space and you see there's a narrow window here for water it's around 10 a 10 microns we'll come back to that in a minute here's co2 it's actually in the water band so it's hard for co2 to make a lot of difference and it's not a very broad band anyway co2 has some other bands but they're at the edge of the blackbody curve so they don't matter very much they're very other other minor gases here so I have to remember this picture so part of the message here is that most of the radiation actually doesn't come from the ground cause there isn't enough atmospheric window and most of the time it's not a clear day anyway this is only for clear days if it's cloudy nothing gets through from the grounds of space and most of the earth is cloudy actually or at least partly cloudy here are some examples of what you see if you look at the infrared coming from the earth and so this is infrared frequency and wave numbers that's the standard unit for infrared spectroscopy solve for example here's the tropical western Pacific and you see that here's co2 there's a big gap eaten out of the infrared but it's not zero there's still quite a bit of co2 radiating to space even though even though the transmissions of space is is that is zero and the reason that happens is if you can't get there from the ground you simply radiate from higher up so co2 radiates into space from the stratosphere but it still is shedding a quite a bit of heat there's water radiating at intermediate altitudes and this is the famous infrared window that is being encroached on by added co2 so the co2 band is slightly broadening as we add more as we burn more fossil fuel so it's important to look at actual data you know I've I've always been a fan of data I'm happy to look at computer calculations I use them myself but that they don't agree with data then they don't mean anything this is one of my favorites this is the Antarctic Ice Sheet and over Antarctica that you can see the ice sheet is really cold 180 Kelvin and so the air above the Antarctic is much warmer than the ice sheet itself so the co2 band in the Arctic is actually any mission yeah well acoustic noise all right well I got up early this morning and I downloaded the latest satellite images of the earth and so here they were at dawn and so this is today it's just beginning to warm up I mean it's just beginning to get light here and in Wisconsin which is where the base is and a and is it's still dark in California at dawn Wisconsin and so what you see and and this is a visible spectrum so white means lots of reflected sunlight dark means that lots of absorb sunlight heating the surface so white is more clouds and so these are cloud tops or and black is cloud free regions but of course this is only for absorption the key for maintaining the temperature of the earth is the balance between the absorption of this visible light and the radiation of the infrared light so let's look at radiation so here is shortwave infrared 3.9 microns this is so shortwave actually that there's practically no impact of it on the cooling of the earth but you can see it easily and the detectors are good so satellite guys like to detect this but what you see here is that almost nowhere is the earth actually free of clouds the entire areas here the eastern Pacific or cloud cover is northern Pacific's is cloud covered the western US as cloud covered clouds all over the place and the continents too and white clouds mean very cold clouds so then this is thermal emission it's not sunlight so you can see even though it's before dawn here on the left side of this picture it's shining just fine at night you know because it's from the heat of the of the atmosphere let's look at a couple more here is saw there's water vapor bands so if you look down at 6.5 microns that's right where the bending mode of water is particularly strong and you see quite a different picture you see big dark areas here and these are the descending branches of the Hadley cell where I showed you these big cells air going up from the equator and falling down they're not nearly as uniform as a picture and they change from hour to hour and day to day but roughly speaking if you average them you get the picture I showed you but they're black because that means that this is water vapor that has gotten to very low altitude so it's quite warm it's not much colder than the surface of the earth so it's radiating extremely well and near the equator you've got water that's been lofted very very high so it's white because it's not releasing much radiation to space and finally here is here's the infrared wind at ten point seven micron and sudden it's like all of the others or pictures we've looked at the earth is covered with clouds it's a little hard to tell looking at this if you see intermediate clouds which cover most of the earth whether they're low warm clouds or whether they're high cold serious but semi transparent clouds so people who analyze this data look at lots of different wavelengths bands and they've studied how particulate s-- attenuate to figure out what fraction of these clouds this crowd cover is low clouds and how much is high cirrus low clouds are all fundamentally cooling mechanisms they shield the earth and they still radiate nicely to space these very high clouds are actually warm the earth because they cut down on the cooling efficiency and they often don't absorb much sunlight they're often quite wispy so the sunlight gets through but the infrared doesn't get out okay but the bottom line let me just emphasize is that the clouds are the 800-pound gorilla this is a point that Freeman has made many times that if you ask why is there so much problem getting the right answer why doesn't a degree with observations the most likely thing is the have not been done right and you can see why from looking at these pictures it's really very hard well here's the one slide summary of global warming theory so that this says that if you increase the radiation coming to the surface because you've got more co2 co2 of course radiates down as well as up so this is the change in the co2 radiation that it will increase the temperature of the earth by what the current temperature is now te which the current temperature is about 288 Kelvin divided by four times the current radiation efficiency of the earth which is I guess it's here 236 watts per square meter this is the sunlight coming in you have to divide by 4 because it's 4 PI R squared for the surfaces of fear and only PI R squared for the surface of a disc so that's where the 4 comes from and then there's the albedo of the earth 30% of the light is reflected before it ever gets turned into heat so anyway this is the formula so on the curves I was showing you that didn't work including Fremont including Freeman's all predict that if you double co2 you get on the order three three and a half degrees Kelvin of warming without exception and and you can see here that that that prediction depends on two unknown things or things not known terribly well it's how much you increase the radiation hitting the surface of the earth from more co2 and then what I didn't mention is this is is the celebrated feedback factor so that what this feedback means is that as you warm the surface of the earth you might get more clouds or you might get less clouds or you might change the temperature distribution you know on how co2 and water vapor radiates so if you put all those things together and unlove them together that's called a the feedback factor and there's a simple formula for it it's it's the rate of change of one minus the albedo with temperature and the rate of change of the effective emissivity with temperature logarithms of both of them okay so that's enough for that but but what I'm going to do now is a switch to look at which of these could be wrong they're probably both wrong but I'd like to focus on the one that most people are most competent on which is the forcing from more co2 this is probably wrong and just as well as the feedback something clearly wrong well okay here's here's the villain and it's uh it's the molecule co2 molecule co2 is a linear molecule here I've brought a model co2 you know it's green right because it's making the plants grow so this is this is a co2 and I I was hoping that maybe we could turn on our elmo for just a minute here because most people you know they listen to the nightly news or Al Gore and don't have any direct experience with co2 you remember we were talking about co2 just across 400 parts per million this summer at Mount Aloha so who would hazard a guess what is the co2 level in the room here I have a meter here so I you know don't be don't be too rash okay well here here's here's what we are today I don't know can you see that 830 it's going up now if you would please stop breathing all right well actually you know your own breath exhale breath the reason it's such a big effect as your exhale breast is 40,000 parts per million so it's it's a huge amount you know the amount in the air is it is trivial so living things producing you could see that in the pictures of the Keeling curve big oscillations summer and winter alright so as I mentioned co2 is a three-dimensional molecule three I mean three atom molecule so it has three normal modes it has a asymmetric stretch mode which does absorb radiation but it much to higher frequencies this is way outside the thermal emission band of the earth it's got the bending mode that I was showing you this mode here so this is the one that causes global warming this floppy mode here and then it's got a symmetric stretch mode which doesn't radiate because as the molecules going in and out there's no dipole moment change and so it's a transmitter without an antenna you if you don't change the dipole moment you can't radiate but there's a hooker here which I'll tell you about and that is you should look at these numbers this is this is the frequency you see it's Satan's number six six six I've always knew known there was something fundamentally threatening here and but but Satan's number is sort of half of the symmetric stretch number so in fact the overtones of this mode interact very very strongly with these infrared in active modes here and that turns out to have a big effect on how co2 causes global warming so let me actually I knew I was gonna have a musician here and so I I thought I'd bring a little uh another model if this is a this is a towel rack and we're Sid drell like yeah anybody okay said you got perfect pitch a guy I need something that bangs on this a little harder that's by the way the bending mode that's the bending mode of Susan you're right it's C+ very good yeah said III you never cease to impress me okay I when I first tried that prop I had it in my briefcase and was trying to get into an airplane on Newark Airport I missed my airplane alright so sometimes you can be too smart for your own good alright so uh so here's uh know if you actually look in detail at the spectrum of co2 these are the bending modes and and of course if it's bending it can be rotating on its axis at the same time so the actual infrared spectrum has axial angular momentum as usual in quantum mechanics one two three four and so these are the states of maximum axial angular momentum they're extremely harmonic they vary by a fraction of a percent as you go up the ladder here but all the other states can mix with the other modes that I mentioned and so the spectrum is a real mess and the guy who first sorted it out was Fermi so this is one of my favorite pictures of family there's alpha right H H bar squared over EC well if you're not a physicist maybe it's wrong it doesn't matter you know he's he's a demigod anyway here's another side that I the best I could get from the end net but what it illustrates is an the reason the co2 molecule spectrum is so complicated because not only is this flopping up and down but it's rotating around as it flopping up and down and the direction I'm flopping it affects the spectrum so if I if it rotates while I'm flopping it up and down we have what you call q-branch radiation so you look at it and you can't see any rotational Doppler shift if it rotates this way but if it's going this way as it rotates then you get big Doppler shifts so that produces the P and the are branches of the molecular band and the thing that's wrong with this is this is a zero state here and a zero state so zero to zero doesn't doesn't work because photon has to have at least one unit of angular momentum alright so now we're getting further and further into the nitty gritties of the how co2 works so in radiative transfer the key quantity is the attenuation rate of radiation and that's the number density of molecules times the cross section so this will be an inverse length and the cross section is is is traditionally written as a line strength times a line shape factor so two factors here the live strength is pretty straightforward it's the square of the dipole moment and it takes into account stimulated emission as well as absorption so it has a factor here which is a correction for amplification as opposed to attenuation of radiation and you know the statistical average so it's got a partition function very straightforward the know the the line shapes is where the rest of this talk is going to be focused on the line shape is something is a function of frequency it tells you whether it's a Lorentzian line or something more complicated like doppler broadened or something like that so the simplest line shape is the Lorentz Ian line shape which in which the intensity of the absorption or the and falls off as the square of the detuning and it is as a width parameter that is entirely entirely controlled by pressure for co2 you know numbers are important and so for co2 you would normally say this is partly you know the natural line width from its lifetime radiative lifetime plus pressure broadening but the radiative lifetime of co2 is 2 or 3 seconds so the radiative broadening natural broadening is completely negative negligible it's entirely due to collisions and sometimes you take into account the the Doppler motion especially at very high altitudes that can be important so it's easy to convulse with a Doppler distribution of velocities if if there's little enough broadening that that makes any difference ok all right so here's here's the situation for co2 these red points are all of the line strengths that I mentioned to you the ability of co2 to absorb radiation you can see on this picture if you actually count them up they're approximately 4000 of them here and the the sharp features in the middle are the Q lines that I mentioned the Q branches of the band and the angel wings on either side are the P and the r branches where there's a lot of rotational Doppler broadening and so they're all there at once and they're all absorbing and for for comparison here are the water lines you can see especially on the low frequency and water is sort of dominating here so this end of the band really doesn't make much difference because it's under the control of water there's less water at the high frequency end but even there it's a bit of a problem ok well these are lines strengths to actually do radiative transfer calculations you need to know cross sections so you have to multiply by lying with factors and here's where the real questions begin to crop up so this is this is cross section you can see it's in units of squares in meters so the biggest cross-sections are like 10 to the minus to the minus 18 even a little bit bigger perhaps 2 3 4 times 10 to the minus 18 this is a central cube cube branch of co2 but it turns out these cross-sections in the middle of the band are so big they don't matter at all so this is already irrelevant for global warming and the cross-sections down here are too small for global warning room so there's a fairly narrow region of cross sections at the left of the band and the right end of the band which can make any difference at all and this is where you can change from an optical depth of a few meters to a few tens of kilometers by changing co2 by a factor of two and if you can't do that it doesn't matter and you can see that what I've done here is plot red for a pure Laurentian or void line you what means you include Doppler broadening and red is taking a more reasonable pharming line shape that agrees with measurements and agrees with simple theory and and you can see it makes a huge difference so if you take the wrong line shape you over predict the warming from more co2 this blue line is too big this is almost certainly wrong but if you talk to people who do the modeling most of them use the blue line okay let's mention one other issue is that these cross sections I mentioned are completely controlled by pressure broadening so they're very different at different altitudes so red is the cross section at ground level at the center of the co2 band it's not so strong that it doesn't differ very much when you don't get to 11 kilometers and top of the troposphere but it's a little bit different and and you don't begin to see the individual lines in the bands until you get way up in near the top of the stratosphere 50 kilometers or thereabouts so this also is hard to systematically take into account so this is to wake you up you know this is Hedy Lamarr and I always admired him tomorrow this you know she not only was a great actress but she was very interested in electrical engineering for some reason and just at the end of the 30s she and Anne until Lamar until submitted this patent to defeat German anti-torpedo devices ever weak expected to give us a lot of trouble the Navy didn't buy it did give us a lot of trouble you know the usual but the idea was this is one of the first spread-spectrum proposals that I know of but the but they were going to communicate acoustically through the water and so they had 88 frequencies which is the number of keys you know white and black on a piano keyboard and some of you would send out these different frequencies at random you know with a code but not a pseudo random so your torpedo knew what the right code was and you knew what the right code was what the Germans wouldn't know what it was so co2 actually works just like this you know as it's radiating and absorbing it's hopping from frequency to frequency well and I mentioned here she had only 88 frequencies but co2 has I think I mentioned here they're roughly 4000 frequencies so at every collision our co2 jumps from radiating at this frequency to this frequency to this frequency was hopping around in frequency space now that turns out to have a big influence on how effective it is in global warming let's see why so here are a couple of limiting cases on how you could hop in frequency Lorentz thought about this back in 1900 and died his model was that you simply randomized the phase so if you keep the amplitude of an oscillator here he took two oscillators frequency 1 frequency 2 and and these red dots are collisions and at the collisions the phase of this oscillation is random and the frequency is toggle between these two and so this is a phase hopping transfer that's this is not very realistic almost certainly this is not what co2 does but that's what's assumed ok this is a bit more realistic this says that if you have a collision that these red spots exactly the same is here that you do shift from one frequency to the other you toggle back and forth but you do not you do not shift the phase so the phase remains constant but the frequency modulate so this is frequency hopping phase papi this also is not what co2 really does but it's a little closer probably so you can see the difference especially if you imagine now that the collision frequencies which here are where these red dots are they're not very frequent so there's plenty of time to get lots of oscillations between collisions if you make that rate very fast the oops wrong way here's what happens so for the spaceship you get this horrible jagged mess if you if you have many collisions for oscillation period so here the red lines lots of collisions but if you have frequency hop it actually gets better because what happens is the oscillator oscillates that the average of the two frequencies of the two lines that are couples so instead of oscillating at one or two you isolate at one point five and so the more collisions to get the narrower the line becomes this is in some communities we would call this Dicke narrowing but it's a common phenomenon it that you see across physics it's the same phenomenon that works in the Merce flower effect and in motion narrowing in magnetic resonance so okay co2 is neither one of these but you can see that it makes a huge difference to line with this you can imagine what happened normos lying with a few four transform that spectrum and this would have quite a narrow line with peaked on the average frequency and indeed here here's just to make the point you can do this analytically but these are simply numerical tests of this so you you write yourself a little computer program and you light it up back and forth between two frequencies more likely Co two frequencies 660 and 670 wave numbers and depending on how you make that hop for example the phase hop that Lorentz assumed in most computer models seemed to assume frequency hop and a chirp which is probably closer closest to the truth where the frequencies just gradually changes the far wings get less and less and less intense and you can say why does that matter and the reason it matters is the structure of the co2 band here has the intensity at the center of the line is how many orders of magnitude one two three four five five or six orders of magnitude more intense than the intensity all of the global warming is coming from the edges of the band and a good fraction of the absorption there can come from far wing broadening of the extremely intense lines in the center of the pan because most of the atoms there most of the molecules are in the ground state okay alright well this is uh this is an example of what the edges of the Bands look like and what a big difference it makes so the the points are cross-sections if you if you take a realistic far wing line shape you know that it's not so not so slowly falling off and and the unwanted things the various dotted lines are for Lorentz broadening and so they're orders of magnitude difference between the realistic lines and and the lines that we get from Lorentz line widths okay well let's talk a little more you can be more quantitative here yeah I think most people know that the heart of radiative transfer calculations is the schwarzschild equation which says if you look say down on the earth to see what brightness is coming up from the surface of the earth that's the brightness of the surface attenuated by whatever the attenuation coefficient is from ground to space and then there's the emission from molecules at every altitude between the ground and outer space so that is the product of the plunk brightness the attenuation coefficient at the altitude of emission and then you integrate over the entire path length plunk brightness of course our famous friend Blanc is it's a quantized oscillator so it has a this Boza factor there and the attenuation rate you have to be careful to include spontaneous emission amplification as well as attenuation this is the line strength in disguise and optical depth is the integral of the intonation rate to space so these are actual measurements here so this is looking down to the surface of the Earth from a high-flying airplane I think I'm not sure but anyway this is the infrared window at 10 microns and there you see the temperature of the earth so you see a pretty good blackbody curve at the temperature of the surface here is the middle of the co2 bad co2 is also on a blackbody curve but this is a blackbody curve at around 220 or 230 Kelvin so it's a cooler blackbody and that's actually the temperature of the middle stratosphere so most of co2 emission to space is coming from the middle stratosphere and then this is water vapor here and if you instead of looking down you look up you see sort of the mirror image of this and so close to the ground level if you look up you see whatever your surface temperature is so you see the surface blackbody curve and and if it's a nice clear day if you look you see the cold temperature of empty space there's no radiation in the window so and here's water vapor here radiating like crazy this is the bending mode of water vapor don't just to give you a feelings many of you don't realize this but the co2 absorbs so well that at the center of band of co2 the the attenuation length is above about six inches so if I had infrared eyes I couldn't see a one of you I couldn't even see my screen you know and so but it you know at the optical at the wavelength where it causes global warming the attenuation length is 10 kilometers it's the depth of the of the tropopause so it has this enormous range of attenuations okay so you can calculate these with it's too late it's too close to drink time to go through this so we'll and here's a calculation that I ran and so this is down welding radiation at the surface versus wave number at the center of the co2 band you basically see only the temperature of the surface it doesn't matter how much co2 is there and it's only and when you get to the edges of the band that you begin to be sensitive to the temperature and to the amount of co2 so but even here you see it makes a huge difference at the edges of the band where where it counts whether you're using a Lorentz profile for the line or whether you're using a more realistic profile the realistic profiles have a lot less warming than the Lorentz profiles commonly used and if you double co2 this is 390 so if you double it oops you can see the shape doesn't change very much it just gets a little broader so you double it broadens hey cut it by half double it broadens so the the effect of adding more co2 is to produce a little bit more less efficient cooling at the edges of bands mostly this one this one almost doesn't matter because of water alright so that's the idea if you now if you put in numbers if you use boy profiles those orange profiles you get you increase the radiation fortune increment from doubling by about a factor at 1.4 okay so we've we're searching on one phone four by the way is not nearly enough to explain the discrepancy between the models but it's one of many factors that needs to be looked at more carefully than has been now okay so I told you that there's a real problem with the performance of climate models they're not even close to being right you know when I think I was thinking coming over here about the situation with solar neutrinos with solar neutrinos you know you had a nice theory and the measurements were not in agreement but it was only a factor of two right with these models here we're talking about factor of ten or more you know it's a huge effect and big good idea to figure out why that's so and get it straight certainly co2 has to cause warming you know I don't deny that certainly co2 is increasing I don't deny that either but you know the the inferences from those two facts are not holding together at all okay well you might ask is there any truth says the answer is yes measurements have been made on this so for example this is a measurement on a balloon so if you look at the limb of the Earth from a balloon and you look at what you actually measure which is the light ray here and you compare it to the best climate models which is the dark grey here this is by the way where all the warming comes from they're not even close ok so there's even there's no question experimentally that there's a serious problem with how you do the far wing modeling for radiation transfer all right it's just a few years ago well I think that's all I'm going to say I'd like to leave some time for a question so let me see is this my last class this is for a Freeman so happy 90th birthday Freeman and I I thought I like this quote here from you know from Henrik Ibsen it says I'm in revolt against the age-old lie that the majority is always right

Channel: Institute for Advanced Study

Views: 243,144

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Id: Oog7-KOtpEA

Length: 53min 16sec (3196 seconds)

Published: Tue Feb 23 2016