I've decided to post this to initialize the Disqus blog on http://cosy.com/Science/Basics.html since its really a continuation of the discussion at James Taylor's Forbes article On 1/24/2012 23:37, email@example.com wrote:
BobOne of the first computations I ever did on this issue was the beginning 1984 when I plotted the lag of temperature versus sun's position over the year in Buffalo New York - as a party invitation .The atmosphere has about a couple of week memory . It stores very little heat -- just enough to keep us warm overnight ( at sea level ) . There is essentially NO lag time .
I support the new Carbon Tax in Australia. It is actually only a tax for 3 years then it will transition to being an emissions trading scheme. That said I do have some reservation about using simply economic tools to try and drive the changes we need. I don't think they will be quick enough. That is not because I think that the effects of AGW will become serious any time soon. It is really a problem for the second half of the century, that is when the impacts start to get severe. However, with the lag time between CO2 emissions and the full impacts on the climate, we need to be acting now with urgency to prevent what will happen when our grandchildren are our age
So is my family better off with a carbon Tax? Compared to what?Compared to making your own choices with your money for the wellbeing of your family .
No Tax & no climate problems? No. No Tax and major climate disruption? Yes. The tax is a much cheaper cost than the impacts of AGW. Tax is just mere money. ;Money is the very blood of modern life . Lack of money leads to starvation . Lack of Money is taking lives .
;AGW has the potential to take lives.ONLY if it is TRUE . It is no more true than that the world is flat .
Including my grand children's. I was born into a world where disease was being conquered and famine, and war. My grandchildren have been born into a world where all those things are likely to come back with a vengeance. I expect to die of old age (Cancer, Heart Attack, Just plain worn out). My Grandchildren may well die of famine, violence, the diseases of poverty, suicide due to despair. Or even worse, they survive by being the perpetrators of such things.Ah , a Malthusian pessimist .
I know you disagree with me on this so let me put a basic proposition. The disagreement about AGW is a disagreement about what the science says is going (or is sufficiently likely) to happen. It does not have a political or philosophical or values aspect to it. None what so ever.There certainly is a high correlation of our view of the dishonesty - and downright retardation of the "science" and that of the centralized use of ( state ) force rather than trust in rational choice by our fellow citizens .
It is simply a discussion about what the physical science says is likely to happen to the physical environment of the Earth in the future if we engage in certain courses of action. If people then want to consider what actions we might take to alter a course of action we are on, there are then additional consequential judgements to be made of a political or philosophical or values nature. Of a moral nature. Or even of a self-centered and selfish nature. But these are not in the least bit relevant to a discussion of what the science has to say. So your comment about the Australian Carbon Tax, to my mind, is not germane to the central question. What conclusions does the science support? Now if you feel that your question is germane, then I would ask you - why are considerations of consequential issues such as taxation systems etc reevant to whether the science is solid?You've got it backwards . Whether the science is solid is totally relevant to whether the redirection by force of a significant fraction of the nation's resources is a plus or minus . To be wrong is to reduce the welfare of the entire citizenry and their progeny . Consider , its a significant factor in the near , if not actual , bankruptcy of Spain .
Looking at the material you have up on your site there seem to be three main points you talk about. 1. The validity of the calculation of the 33 K colder figure. 2. How can an object at a certain distance from the Sun have a surface temperature that is warmer than its distance from the Sun suggests? 3. The effect of CO2 is saturated so extra CO2 can't do much. Let me reiterate what I said about point 1 then give you some ideas to think about regarding point 2. Point 3 can be deferred till a later time. 1. The point of my posts about different AE values for a hypothetical Earth was to highlight that the surface temperature one calculates using SB is extremely sensitive to how well you are accounting for the actual AE value for the system you are examining.I again conclude you do not know how to calculate the temperature of a radiantly heated colored ball . You don't how to answer my question about what absorption spectrum ( paint job ) would maximize the temperature of a ball in our orbit . I'm not even clear that you understand the basic fact that for a flat spectrum ( gray ) ball AE makes no difference ( except for the singularity at AE = 0 ) . You reenforce this conclusion below . And you seem to have not read my syllabus for the Climatewik.org Essential Physics page . The first essential extension to my computation for arbitrarily irradiated arbitrarily shaded gray balls is to add spectral maps to the celestial sphere and ball . Only when that is nailed down is there any point in attacking more complex ( semi-transparent layers ) . What would be helpful , is if you have sources for full spectra of interest . EG , the sun , CO2 , H2O vapor , cloud , snow . The spectra have to cover the full range from UV to long IR . Like the data behind http://upload.wikimedia.org/wikipedia/commons/7/7c/Atmospheric_Transmission.png . First thing is to calculate equilibrium temperatures for simple uniform balls with those spectra . My bet is that simply computing the temperature for that "Total Absorption and Scattering" spectrum will reduce our "unexplained" ~ 10c variance from the 279k of a gray ball down to less than 1c .
So drawing conclusions about how warm the No-GHG Earth would be is difficult. And the 33K figure is only used as an indicative and rather idealized number. Most articles that refer to it will point out something like 'all else being equal' - the all else being Albedo. So you need to be very careful that any analysis you do is cognoscente of this. The 0.3 albedo figure given for the Earth is a composite of 3 different components. And only 1 of these components is then relevant in your calculation. Reflection off the atmosphere happens at very high angles of incidence, so around the dawn & dusk edges of the planet. Reflection off clouds happens across a wide range of angles of incidence but varies substantially with cloud type - clouds with more ice crystals reflect more than clouds that are mainly water droplets. And the important thing to remember is that all reflected light is not part of the energy balance. Reflection isn't absorption and constitutes energy that the climate system cannot absorb 2. I would like to put forward a thought experiment that might shed some light on the question of how a planet can be warmer than its distance from the Sun suggests. Your calculations (if I have understood them correctly) are essentially a model made of 3 components. Sun, Earth's Surface, Deep Space. This model is inadequate. If one is to model the Earth's temperature, the starting point is that the absolute minimalist model has 4 components - Sun, Earth's Surface, Earth's Atmosphere, Deep Space. So lets start with a simple case - a solid sphere (planet) at 150 million kms from the Sun, with the same diameter as the Earth, and a surface AE value of something. Your calculations will produce a result for the surface temperature (Ts) of this sphere, depending on the AE value you give it. Now lets add a shell, around the original solid sphere. Concentric with it, somewhat larger diameter than the sphere so they are not in contact. And not very thick. Then we add some interesting optical properties. This shell is completely transparent to EM Radiation in the frequency ranges associated with Sunlight. UV, Visible & Near IR. They all pass through the shell and reach the sphere below. However, the shell is completely opaque to Far IR radiation. The frequency ranges where objects such as the Earth radiate. This might seem a rather arbitrary choice but it is attempting to model, crudely, the behavior of the real atmosphere. Lets add an additional aspect which is that the shell is 100% reflective in the Far IR range.
So, what happens to this Sun, Sphere, Shell, Space system - you can model it in APL. Sunlight passes through the shell and is absorbed by the inner sphere (apart from whatever is reflected based on the AE value you give the sphere). The sphere then radiates according to S/B and the AE value. And 100% of this is reflected back from the shell! The sphere (Earth) is absorbing energy from the Sun but can't get ANY of it back out to space through the shell. So the sphere starts to warm. Eventually it warms so much that it starts to radiate in the frequencies that the shell is opaque to - Visible, Near IR. Once its temperature has risen high enough, it will be able to get enough energy out through the 'solar window' in the shell that it reaches thermal equilibrium and doesn't warm any more. At the same time, the shell, since it is absorbing 0% of energy from anything would have a surface temperature of absolute 0. So what would this bizarre planetary system look like to a visitor from space? A bizarre spectrum of strong radiation in the Near IR/Visible range but zero from anything lower. What does the temperature of this system look like? Is it as warm as a hot frying pan or even a glowing red-hot poker as the Near IR/Visible spectral data suggests. Or is it at absolute zero, as the far IR spectral data suggests. It is actually both. The outer surface of the shell is at 0 K. But the inner sphere (planet) is a red-hot poker. I am not suggesting that this is a real world scenario, just a thought experiment. However, this behavior of being transparent at some frequencies and opaque at others is very much real world behavior. The atmosphere behaves like this. And there are a range of salts and other crystalline materials that have this property of being transparent in the visible and opaque in the IR realm. And this differential opacity has a serious impact. Now lets start adjusting our thought experiment. The shell is still opaque. But instead of being 100% reflective, we start to dial that down and let it have an AE value > 0. Now the shell will absorb some of the energy that strikes it rather than reflecting it. So the shell can start to warm above 0 K. As a result, the warmer shell is now going to radiate some energy out to Deep Space. So now the outgoing energy for the whole system becomes a mix of Far IR radiated by the shell, and Near IR/Visible radiated by the sphere through the 'solar window'. What happens if we dial the reflectivity of the shell right down to zero? An AE of 1 - black body. Now all the energy striking the shell from the surface below is absorbed. And it then radiates some of this to space. How much? The SB eqn is based on a surface at a temperature T, and an AE value of something - here 1. So that surface will radiate a total amount of energy out from that surface given by S/B. But in the case of our shell it has 2 surfaces, above & below. And each surface will radiate according to S/B, driven solely by the temperature of the shell. So, for example, if the shell was absorbing 1000 W/M^2 from the surface then the upper and lower surfaces of the shell will each radiate 500 W/M^2, and this will determine the temperature of the shell (I am ignoring in this thought experiment any issues with internal conduction of heat within the shell). So what will be the thermal balance for our hypothetical system now that we have dialed AE for the shell up to 1? Assuming that now we don't need to use the 'solar window' to get any energy out we have the following balance. Solar incoming must equal Shell outgoing for energy balance. Shell outgoing is 1/2 of Surface outgoing since the shell only radiates half the energy it absorbs outwards. Therefore, for energy balance, the sphere surface needs to radiate 2 times the solar incoming. 1/2 of this escapes to space through re-radiation from the shell. The other half is radiated back to the sphere. So, what is the perspective from space looking down at our sphere/shell system. It looks like a black body at the temperature one would expect at this distance from the Sun. Because that is what the shell is doing. But inside the shell, the sphere is radiating twice as much energy. So its temperature is 2^-4 of the Shell's temperature: 1.189 times the temperature of the shell. So if the shell is at 279K for its distance from the Sun (as an example), the sphere inside would be at 331 K. So a basic concept here. What the temperature of a sphere(Earth)'s surface is depends on what the restriction are on the flow of energy to space. To give a corollary, in many Heat Transfer calculations, a method used is to model the system as a series of flows with different pathways constituting different 'resistances'. Then the analysis becomes like the analysis of an electrical circuit. Your 3 part model doesn't allow for the 'resistance' that the atmosphere imposes on the heat flows and thus the changes that this creates in the various 'capacitances' within the system - the temperature of things. So, a basic thought experiment that shows how a 'shell' or 'shield' around a planet that interferes with the flux of energy from the surface of the planet can change the surface temperature of the planet. I haven't included things like allowing the shield to be partially transparent in some parts of the Far IR range. Another approach you can take is to then model multiple shells, one above the other, each with different optical properties - this actually starts to approximate the atmosphere more closely Have a look at some APL code for this Bob, see what you get. And you don't need to delve into differing AE values with wavelength - I assume that is what you mean when you ask people to help you with spectra. Just a single AE, fixed across wavelengths is sufficient for this thought experiment. Gotta Go, lots of work, Australia Day coming up which is busy in my business. Send me your thoughts. But please, look into the maths of my examples Regards
Glenn in Oz