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noggin

A growing groundswell of opinion?

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Mmm, I'm not sure anyone else saw that inference, presumably the same 'anyone else' that saw your original point. Anyway, I thought the way you checked yourself to ensure careful reading was subtle and most dignified. Hats off to you and a lesson to us all.

Re the physics, complexity simply isn't an issue. It is a fundamental law of physics that energy can neither be created nor destroyed. If I have a solid canister that will hold 100 marbles, and I have 1000 equally sized marbles, of a range of colours, it doesn't matter whether I put red marbles in, blue in, green, or any combination: the capacity is 100 marbles.

Earth can only get hotter IF there's a change in the net flux - it's that simple. That means either more energy in or less out. You MIGHT make an argument around unequal distribution, in which case if we didn't or couldn't measure the surface equally some energy might 'hide' or be over-emphasised, but the problem with that argument is that the qualitative evidence of warming is just too widespread and consistent for errors of measurement to be plausible. Your own graphs show that the flux in isn't increasing so all that's left is a reduced reradiation, and that retained energy is being reflected to some extent in the temperature of all surfaces.

Well it's round and round and round we go. Complexity most certainly is the issue. I have not even intimated that somehow energy is being created or destroyed (which would obviously break the law of conservation of energy, aka the first law of thermodynamics - yes, I am familiar with it).

Let me just try a slightly different analogy, just to see if you are misunderstanding me still...

A container of water has a hole in the bottom which allows 5 drops out every second.

A tap drips water into the container at a rate of 1 drop per second.

To begin with the container shows no net increase in water volume.

After a while the tap's dripping increases at a rate of 1 extra drop per second.

Once the rate reaches 6 drops per second, the container starts to slowly fill at a rate of 1 drop per second.

Even if the rate stops at 6 drops per second, so there is no increase in drip rate, the container will continue to fill up.

That's the basic principle that I am getting at, though I concede that this analogy is not a perfect one either as it stands (though if I had the time and energy I could probably adapt it to make it a closer analogy, but that would involve overcomplicating it!).

CB

EDIT - I would like to add that I'm not just a one-trick pony! I do have various issues with AGW, but I'm focusing on this Solar thing right now because it came up in the debate. I am not trying to pin all the blame onto the Sun - just a fairer share of the blame than it currently gets! :rolleyes:

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Well it's round and round and round we go. Complexity most certainly is the issue. I have not even intimated that somehow energy is being created or destroyed (which would obviously break the law of conservation of energy, aka the first law of thermodynamics - yes, I am familiar with it).

Let me just try a slightly different analogy, just to see if you are misunderstanding me still...

A container of water has a hole in the bottom which allows 5 drops out every second.

A tap drips water into the container at a rate of 1 drop per second.

To begin with the container shows no net increase in water volume.

After a while the tap's dripping increases at a rate of 1 extra drop per second.

Once the rate reaches 6 drops per second, the container starts to slowly fill at a rate of 1 drop per second.

Even if the rate stops at 6 drops per second, so there is no increase in drip rate, the container will continue to fill up.

That's the basic principle that I am getting at, though I concede that this analogy is not a perfect one either as it stands (though if I had the time and energy I could probably adapt it to make it a closer analogy, but that would involve overcomplicating it!).

CB

EDIT - I would like to add that I'm not just a one-trick pony! I do have various issues with AGW, but I'm focusing on this Solar thing right now because it came up in the debate. I am not trying to pin all the blame onto the Sun - just a fairer share of the blame than it currently gets! :D

C-B, it's a good analogy, and I completely understand the point you've been making - the thing is energy doesn't work like water. Water is ALWAYS water, so if you pour more in than can escape then you get a build up until the storage vessel bursts or overflows. Energy is simply a flux.

Say you blow a hairdrier into a sealed drum through a pipe. The air coming out of the hairdrier is, say, 40C. The drum starts at say 20C. It doesn't matter how long you blow your hairdrier for, the air in the drum is NEVER going to get warmer than 40C - assuming that there is a pressure release valve of course.

The same would be true if I set a two bar fire close to the drum. It might take a day or so, but eventually the air inside the drum would have got as hot as it was going to get.

But turn either the hairdrier off or the fire off and pretty soon the air in the drum cools down - it is radiating energy but no longer receiving it. So, when there's a step change in available energy the receiving body responds but ONLY until an equilibrium is reached. Energy cannot, like water, build up, at least not in thermal form. This is why, if you put wet clothes on a radiator for as long as takes them to dry - say an hour - they do not dry linearly (i.e. 1% per 36s). The first phase involves the water in the clothes being warmed until the temperature is the same as that of the radiator: that might take twenty minutes (this is a simplification because there's differential heating ongoing), but once equilibrium is reached there is still a flow of radiant energy, and still SOME conduction (energy is still leaking away from the clothes to the cooler air) and because more HEAT cannot be generated the energy converts to that convenient form used by physicists when the numbers don't balance: latent energy, and here the latent energy is important because IT is sufficient to allow some molecules at the surface of each drop of water to be bounced free, just as they are when water reaches boiling point (except at 100C and a standard atmosphere the whole mass becomes unstable). The ONLY way that the air in the drum could get even hotter would be if we could make the hairdrier hotter, or add a hotter bar to the fire.

So in this model we don't heat up more once the initial impact of changing flux has kicked in, which is why I offered LAG as the only possible explanation.

There is, though, another reason why we might heat up, and that's NOT because we let more energy in, but because we let less escape.

In your water drum the build up was being caused by an excess rate of drip. What if, instead, the drip stays the same but you close the leak? And there you have the greenhouse effect double glazed, which is the whole argument behind AGW. The rate of reradiation of energy is being reduced. If only for albedo this is undeniable. With a reducing white surface more energy is absorbed and less reflected. But the CO2 acts like a duvet, trapping escaping energy inside the troposphere in particular. There's no increase in drip required, but if you did increase the drip rate then all that would happen would be we'd fill up even more quickly.

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C-B, it's a good analogy, and I completely understand the point you've been making - the thing is energy doesn't work like water. Water is ALWAYS water, so if you pour more in than can escape then you get a build up until the storage vessel bursts or overflows. Energy is simply a flux.

Say you blow a hairdrier into a sealed drum through a pipe. The air coming out of the hairdrier is, say, 40C. The drum starts at say 20C. It doesn't matter how long you blow your hairdrier for, the air in the drum is NEVER going to get warmer than 40C - assuming that there is a pressure release valve of course.

Sorry I've trimmed down your post in the above quote, SF - didn't want to waste space by needlessly repeating it, but I've kept the key part.

Thanks for the clarification - I wasn't sure if we were talking at crossed purposes or not. Yes, water is always water, but could you clarify what you mean by "Energy is simply a flux"? Energy is certainly subject to flux (which is the Latin word from which we derive the English word "flow"). In Physics the word "Work" is used to describe the flux of energy - that is, the transfer of energy from one system to another.

The point is that your argument requires that the Earth be "fully energised" at each instant of solar output's increase so that when that output levels off the Earth is as energised as it can be, and can be energised no more.

In fact, to use your analogy above, if the air coming out of the hairdrier is at 40C then it is at a constant heat, and yet the drum will continue to warm until it reaches the same temperature. The larger the difference between the output temperature and the object being warmed, the longer it will take for the object to be warmed to that temperature.

:doh:

CB

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My poor brain is not willing to allow me to follow your tiff guys. For us 'no brainers' hows about.....

If we were a 'rock' of a planet then any solar 'fluctuation' would be a lot more likely to cause an instant effect on the planet. We are not. A load of the incoming solar energy goes into 'non-atmospheric warming', some of which can take many tens of years to finally enter the atmosphere (the warming of the deep oceans). Some goes into 'state changes' as we witness in the Arctic over summer.

What happens when these 'heat sinks' are no longer functioning (most of the ice sheets melted, deep oceans warmed)? Do we expect that the same amount of incoming radiation to cause greater atmospheric heating?

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My poor brain is not willing to allow me to follow your tiff guys. For us 'no brainers' hows about.....

If we were a 'rock' of a planet then any solar 'fluctuation' would be a lot more likely to cause an instant effect on the planet. We are not. A load of the incoming solar energy goes into 'non-atmospheric warming', some of which can take many tens of years to finally enter the atmosphere (the warming of the deep oceans). Some goes into 'state changes' as we witness in the Arctic over summer.

What happens when these 'heat sinks' are no longer functioning (most of the ice sheets melted, deep oceans warmed)? Do we expect that the same amount of incoming radiation to cause greater atmospheric heating?

Hi GW,

That's certainly part of my argument - that not all warming is atmospheric. Bringing non-functioning heat sinks into it complicates it yet further, and since I haven't boned up on the current state of affairs with heat sinks then I unfortunately can't comment. Maybe I'll start looking into that next...!

:doh:

CB

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Thanks for your patience C-Bob. I've been trying to 'break the back' of a job for my sister-in -law but it won! Consequently I'm a little woozed out on DHC's so ,though I may not 'care as much' as usual I'm also less able to figure what not to care that much about!!!

My 'worries' over our ice sheets is also that they are likened to 'sleeping Giants' .It would seem until major events take place they are viewed as being 'asleep' .Not true. So much of the initial 'awakening' is unseen and a lot of energy is being sapped away during this 'unseen phase'. In so far as any 'point of no return' is concerned I suspect we will be far past it by the time we start witnessing things that Mr J.Public can appreciate.

Part of the 'Lovelockian' stance on the climatological 'leaps/shifts' are mainly due to the planets 'soaking up' of energy until the sinks are at parity and then all of the energy that used to be absorbed is free to have direct impacts on the surface/atmosphere. If so then the 1900-40's heating made a start (as the 'Greenland paper on it's ablation through that period, including calving bergs bigger than Manhattan island, shows us) then the recent (1980's onward) renewal in heating is building on these 'foundations'. This would bring us a lot closer to very worrying times that looking at the warming as a smooth line event from 1850 until present would not show us.

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My challenge is WHY would you only pick ONE piece of random forcing which just happens to probably have a cooling effect? If you're going to model something then model consistently - i.e. include unknown events or exclude them, but don't just cherry pick.

I'm presuming when you're gardening in spring, say, and looking after tender plants you don't, having seen a forecast for frost, just hope that a sheet of unforecast cloud will blow over and avert the damage, but rather that you go out and protect those plants.

One of the reasons why we elect leaders and have Government is to try to ensure that decisions are made in the common good which we would either not choose to, or not be able to, effect individually.

Stratos.....re the first sentence here....I am just chucking in one cooling possibility as an example, because I seriously doubt that the report presenters have done anything OTHER than cherry pick. Passion for a subject can result in blinkeredness.

Re the second sentence.......of course not, but that is not what we are talking about.

Re the third sentence......there has to be an Opposition to temper things and to help avoid extremes of policy which may otherwise be harmful or dangerous. History is littered with such policies.

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Neither of the two of you have mentioned that the earth also produces a net output of energy. Have you thought about that?

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Neither of the two of you have mentioned that the earth also produces a net output of energy. Have you thought about that?

Hiya Hiya!

The output of our little rock is fairly constant when compared to the fluctuations of solar input as dictated by solar activity/prossesion etc. Were there no Sun our output would mean diddly to our planet apart from around the vents thenselves.

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Hiya Hiya!

The output of our little rock is fairly constant when compared to the fluctuations of solar input as dictated by solar activity/prossesion etc. Were there no Sun our output would mean diddly to our planet apart from around the vents thenselves.

I doubt it has been constant for the last 250 years, thats why I brought the issue up.

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Re the physics, complexity simply isn't an issue. It is a fundamental law of physics that energy can neither be created nor destroyed. If I have a solid canister that will hold 100 marbles, and I have 1000 equally sized marbles, of a range of colours, it doesn't matter whether I put red marbles in, blue in, green, or any combination: the capacity is 100 marbles.

LASER, acronym for Light Amplification by the Stimulated Emission of Radiation.

Ok,here's how it works. In a glass cylinder which has a total mirror at one end and a mirror at the other end which isn't quite complete ( say 90% coverage ),there's a mixture of gases,typically nitrogen,helium and carbon dioxide in precise proportions. Light is applied to the outside of the tube (keeping things very simple here) while an electric current is passed through the gas mixture. This application of external energy (electricity and light) causes excitation of the gas molecules in the tube. 'Excitation' means that the electrons in orbit around the molecular nucleus will 'leap' into the next higher orbit. This moment is transitory as the excited electrons will spontaneously fall back to their normal state. In doing so a photon of light (energy!) is released. The light,being in a tube with mirrored ends has nowhere to go,so it bounces back and forth between the mirrors. Meanwhile,the laser is continously 'pumped' with light and energy,(though it would still work without using applied electricity but be of low power)thus perpetuating the emission of photons. And so the light 'accumulates' inside the tube,except for the portion of it which escapes from the partial mirror. The laser light,having been propagated inside a perfectly straight tube under precise conditions,is ultra pure and of a single wavelength (coherant). What's all this got to do with the matter at hand?? Well,it's an extension of what SF and C-Bob were on about earlier. In a laser,the external light applied isn't actually 'used', and the applied electricity simply passes through the tube to complete a circuit rather than doing any work (rather like a catalyst in a chemical reaction I suppose ). So where does the laser's energy come from,considering that the gases mentioned earlier remain unchanged?? Hmm,I of all people should know that,but I've never thought about it 'til now. But on the face of it,it seems that light energy is created from 'nothing' seeing as nothing is actually used up! Any nuclear phycisists care to 'shed some light' on this? With direct reference to SF's comment above,it would appear that laser light(energy) is created from nothing,since nothing is being used up or changed. I'm missing something surely,but what? Only thing I can come up with is that the applied light must be the same or more than the beam obtained,only the nature of it has changed?? Hmm,but the gas molecules will continue to oscillate between normal state and excited and thus emit photons (energy!!) indefinitely. Wish I'd never started now.

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I don't know anything about lasers but it's certainly true that energy cannot be created or destroyed. There is no free lunch - everything has to come from something. Matter is energy too, e=mc2 and all that.

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LASER, acronym for Light Amplification by the Stimulated Emission of Radiation.

Simply put, the light entering the laser is white light - a mixture of all wavelengths - which has a certain energy. The light emitted from the laser is of only one wavelength - typically a longer one (longer wavelengths of a particular amplitude have less energy than shorter wavelengths of the same amplitude). The energy absorbed by the gas is turned into a photon of a particular wavelength, and any excess energy is put into the amplitude of the light wave (yes, I know I'm mixing up light as particles and waves, but that's just the way it is :) ). The higher the wave's amplitude, the brighter the light, much the same way as greater amplitude of a soundwave makes the sound louder.

The gases in the laser determine the colour of the light beam emitted - different combinations of gas give different colours.

I think that's right at least!

:huh:

CB

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We sceptics/questioners are often asked if we consider ourselves, almost above the climate scientists, the oft repeated questions being either " so you know more than them then?" or "so the scientists are delusional, they've got it all wrong?" The impression created is that sceptic scientists are a tiny minority who don't know what they are talking about.

Here's a list of well respected scientists who think the accepted theory of AGW and it's predictions is so wrong, they are willing to publicly say so. It's also worth noting, this list was drawn up in response to invitation, it took a mere SIX DAYS from invitation to presentation; I'd say that indicates quite a determined resolution in their confidence. It's also worth baring in mind, if this many are willing to sign in six days by invitation only, imagine how many more signatures may have been added if this were made public weeks beforehand.

http://www.nationalpost.com/news/story.html?id=164004

http://www.canadafreepress.com/index.php/article/851

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if I'm less of the fool I think myself to be then I'd be srprised if many others signed up after day 2.

In fact it'd be intereasting to see the breakdown of 'sign-ees' and 'swiftness of respose' dont'cha think?

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Lets see if we can make this more coherent:

LASER, acronym for Light Amplification by the Stimulated Emission of Radiation.

Ok,here's how it works. In a glass cylinder which has a total mirror at one end and a mirror at the other end which isn't quite complete ( say 90% coverage ),there's a mixture of gases,typically nitrogen,helium and carbon dioxide in precise proportions. Light is applied to the outside of the tube (keeping things very simple here) while an electric current is passed through the gas mixture. This application of external energy (electricity and light) causes excitation of the gas molecules in the tube. 'Excitation' means that the electrons in orbit around the molecular nucleus will 'leap' into the next higher orbit.

So far so good

This moment is transitory as the excited electrons will spontaneously fall back to their normal state.

Falling between higher to a lower level is random and will occur only for a proportion of electrons and as you correctly identify, this is called spontaneous emission.

In doing so a photon of light (energy!) is released.

Because the electrons can change shells only at specific quanta of energy and the wavelength of light is directly proportional to energy, the photons will all be at the same wavelength characteristic of the gases used.

The concept of stimulated emission (very different from spontaneous) now needs to be introduced: When a photon of sufficent energy passes an electron in an outer shell, it can cause that electron to drop an energy level i.e. from an outer to a lower shell. In the process giving off another photon. Critically, the new photon is the same wavelength as the first and propagating in the same direction. We now have two photons of the same wavelength travelling in the same direction.

The light,being in a tube with mirrored ends has nowhere to go,so it bounces back and forth between the mirrors. Meanwhile,the laser is continously 'pumped' with light and energy

You can now see that the external light is used as a catalyst to not only promote stimulated emission, but to also provide the energy to allow electrons to jump from a lower energy level to a higher level.

(though it would still work without using applied electricity but be of low power)

In which case, the external energy would need to all come from the applied light source making the process quite inefficient. The electric current provides a continuous supply of electrons as well as removing electrons from the outer shell of the gas atoms and providing energy for electrons to jump from lower shells to higher energy levels. In this way electrons are constantly replaced, changing shells and therefore providing the excess power needed to sustain an efficient process.

thus perpetuating the emission of photons. And so the light 'accumulates' inside the tube,except for the portion of it which escapes from the partial mirror. The laser light,having been propagated inside a perfectly straight tube under precise conditions,is ultra pure and of a single wavelength (coherant). What's all this got to do with the matter at hand?? Well,it's an extension of what SF and C-Bob were on about earlier.

OK

In a laser,the external light applied isn't actually 'used', and the applied electricity simply passes through the tube to complete a circuit rather than doing any work (rather like a catalyst in a chemical reaction I suppose ).

Incorrect, see previous para.

So where does the laser's energy come from,considering that the gases mentioned earlier remain unchanged?? Hmm,I of all people should know that,but I've never thought about it 'til now. But on the face of it,it seems that light energy is created from 'nothing' seeing as nothing is actually used up! Any nuclear phycisists care to 'shed some light' on this? With direct reference to SF's comment above,it would appear that laser light(energy) is created from nothing,since nothing is being used up or changed. I'm missing something surely,but what? Only thing I can come up with is that the applied light must be the same or more than the beam obtained,only the nature of it has changed?? Hmm,but the gas molecules will continue to oscillate between normal state and excited and thus emit photons (energy!!) indefinitely. Wish I'd never started now.

From my previous explanation, the laws of thermodynamics are maintained. The photons generated through both spontaneous and stimulated emission get their original energy from the gas initially in its steady state but then from the external electric current and external light source.

ffO.

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Simply put, the light entering the laser is white light - a mixture of all wavelengths - which has a certain energy. The light emitted from the laser is of only one wavelength - typically a longer one (longer wavelengths of a particular amplitude have less energy than shorter wavelengths of the same amplitude). The energy absorbed by the gas is turned into a photon of a particular wavelength, and any excess energy is put into the amplitude of the light wave (yes, I know I'm mixing up light as particles and waves, but that's just the way it is :) ). The higher the wave's amplitude, the brighter the light, much the same way as greater amplitude of a soundwave makes the sound louder.

The gases in the laser determine the colour of the light beam emitted - different combinations of gas give different colours.

I think that's right at least!

:doh:

CB

But you are still not getting a free lunch, just a conversion of energy, at a certain efficiency. X watts in, X-y watts out. y is lost as heat.

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Simply put, the light entering the laser is white light - a mixture of all wavelengths - which has a certain energy. The light emitted from the laser is of only one wavelength - typically a longer one (longer wavelengths of a particular amplitude have less energy than shorter wavelengths of the same amplitude). The energy absorbed by the gas is turned into a photon of a particular wavelength, and any excess energy is put into the amplitude of the light wave (yes, I know I'm mixing up light as particles and waves, but that's just the way it is :) ). The higher the wave's amplitude, the brighter the light, much the same way as greater amplitude of a soundwave makes the sound louder.

The gases in the laser determine the colour of the light beam emitted - different combinations of gas give different colours.

I think that's right at least!

:doh:

CB

Partially correct but not the excess energy bit:

The white light is a band spread of energy of differing quanta levels. The laser light is coherent because electrons drop from an outer to lower shell at a specific quantum of energy determined by the gas used. The gas loses energy when photons are produced. The excess energy is needed to raise electrons from inner shells to outer shells in the gas molecules from where they can then drop giving up their energy as a photon.

The amplitude of the light is simply the number of photons created and their density at any given time.

i.e. The amplitude of the laser light is a function of how much energy the gas is losing in a given time.

See my previous response to laserguy.

ffO.

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We sceptics/questioners are often asked if we consider ourselves, almost above the climate scientists, the oft repeated questions being either " so you know more than them then?" or "so the scientists are delusional, they've got it all wrong?" The impression created is that sceptic scientists are a tiny minority who don't know what they are talking about.

Here's a list of well respected scientists who think the accepted theory of AGW and it's predictions is so wrong, they are willing to publicly say so. It's also worth noting, this list was drawn up in response to invitation, it took a mere SIX DAYS from invitation to presentation; I'd say that indicates quite a determined resolution in their confidence. It's also worth baring in mind, if this many are willing to sign in six days by invitation only, imagine how many more signatures may have been added if this were made public weeks beforehand.

http://www.nationalpost.com/news/story.html?id=164004

http://www.canadafreepress.com/index.php/article/851

It is true there are a large number of proper qualified scientists in every corner of the globe who have a differing view on AGW. It really is beyond reasonableness to expect us to believe these are all deduled madman somehow with a vested interested in throwing a spanner into the great AGW works. I just don't buy the fact all this research is flawed, the sheer number of highly educated dissenters is way beyond what you any scientific analysis can dismiss. It really has to be remembered and is a statistical fact that you can scale up the number of signed dissenters on any argument that goes against the grain, for every one that signs there will be 4 more who wanted too. Its interesting how many dissenters originate from The Netherlands a country not known for its oil rich economy or anti environmental policies, I guess this bunch must just be mad deluded dutchman who's PHD's are worthless bits of paper.

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Partially correct but not the excess energy bit:

The white light is a band spread of energy of differing quanta levels. The laser light is coherent because electrons drop from an outer to lower shell at a specific quantum of energy determined by the gas used. The gas loses energy when photons are produced. The excess energy is needed to raise electrons from inner shells to outer shells in the gas molecules from where they can then drop giving up their energy as a photon.

The amplitude of the light is simply the number of photons created and their density at any given time.

i.e. The amplitude of the laser light is a function of how much energy the gas is losing in a given time.

See my previous response to laserguy.

ffO.

Thanks for that ffO (and Chris, too!). I was having a bit of a senior moment and couldn't quite recall the details... :doh:

CB

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I'm glad we have straightened out about the laser, ffo really knows his/her stuff, but that isn't what happens to a CO2 molecule in the atmosphere. I don't know if that was the original intention of the analogy or not.

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I'm glad we have straightened out about the laser, ffo really knows his/her stuff, but that isn't what happens to a CO2 molecule in the atmosphere. I don't know if that was the original intention of the analogy or not.

Quite true, on all counts! We are still left with the thorny issue of exactly what it is that atmospheric CO2 actually does to Earth's temperature. Is the additional CO2 of the last 100 years or so actually significant? I have been arguing that it isn't, and that there are other possible explanations for recent warming, but we don't seem to have got any closer to an agreement.

:rolleyes:

CB

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I'm glad we have straightened out about the laser, ffo really knows his/her stuff, but that isn't what happens to a CO2 molecule in the atmosphere. I don't know if that was the original intention of the analogy or not.

Absolutely correct. The laser is not even a close analogy for the greenhouse effect, in fact the actual glass greenhouse mechanism is also a poor analogy.

Incoming solar radiation is a band-spread of electromagnetic radiation; The incoming energy is has a spread of wavelengths from roughly well below 250nm to above 2500nm i.e. high energy beyond ultraviolet, x-rays etc to infra red at a much lower energy.

Visible light comprises wavelengths between 400 - 700nm approx.

Most of the energy received by the Earth falls within the visible and infra-red ends of the spectrum.

Atoms (atmosphere and ground / sea etc) absorb the incoming solar radiation which affects either their spin, vibration, quantum state etc.

The bulk of the atmosphere: oxygen (O2) 21%, nitrogen (N2) 78% and argon (Ar) <1%; do not interact with infrared radiation significantly. While the oxygen and nitrogen molecules can vibrate, because of their symmetry these vibrations do not create any transient charge separation. Without such a transient dipole moment, they can neither absorb nor emit infrared radiation. In the Earth’s atmosphere, the dominant infrared absorbing gases are water vapor, carbon dioxide, and ozone (O3). The same molecules are also the dominant infrared emitting molecules.

Much of the band-spread of solar radiation reaching the Earth is absorbed at the surface or the sea and re-radiated at lower infra-red wavelengths.

Carbon dioxide absorbs IR radiation. Molecular collisions transfer this energy to heating the surrounding bulk gases - Nitrogen, Oxygen, Argon. Other CO2 molecules are vibrationally excited by collisions. The greenhouse effect due to CO2 exists because this vibration is easily excited by infrared radiation.

The key thing to note is short wavelength incoming solar radiation reaching the ground is converted to longer wavlength infra-red radiation which is more easily absorbed and transfered to the rest of the atmosphere by the GHG's.

Another key point which both Stratos and I made earlier is that the shorter wavelength energy absorbed at the surface (ground) is given up very rapidly to the atmosphere as re-radiated longer wavelength infra-red. The transport mechanism from the oceans to the atmosphere is primarily through evaporation. Once in the atmosphere, the bulk of the heat transfer is via convection and conduction.

By this particular measure, water vapor can be thought of as providing 36% of the greenhouse effect, and carbon dioxide 9%.

However water vapour stays in the atmosphere for far less time than CO2. Doubling CO2 effectively doubles the amount of infra-red energy capable of transfer to the atmosphere. Higher temperatures increase evaporation into the atmosphere which is also a much more efficient GHG. However this is a feedback mechanism and requires elevated temperatures whereas CO2 is a primary mechanism creating the conditions to increase temperature.

In this way increases in incoming solar radiation will also heat the Earth, however there will be a significant lag before atmsopheric temperatures rise. CO2 and other GHG's begin work immediately at creating a more efficient mechanism for transfer and retention of thermal energy.

This later reasoning is why the IPCC believes it gives the most plausible account of the rate of increase of temperatures which even significant increases in solar radiation alone cannot account.

Open the gates and unleash the dogs of war!

ffO.

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Just read the responses to my laser query. Very much appreciated everyone,especially to FFO of course. Really has cleared up something I was starting to puzzle over but your explanation has saved me the bother of reading up on it all. Was your great grandad Einstein? :rolleyes: .

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Open the gates and unleash the dogs of war!

ffO.

Exactly what I couldn't be bothered typing (again).

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