Climate Change - The Scientific Debate
Discussion
LongQ said:
plunker said:
Not lately that I'm aware. I think in terms of where research is focussed the CO2 science is considered pretty solid and a 'given' so the answer is more likely to lie elsewhere.
Au contraire mon ami. That is precisely the time when alternatives should be reviewed in detail.plunker said:
LongQ said:
plunker said:
Not lately that I'm aware. I think in terms of where research is focussed the CO2 science is considered pretty solid and a 'given' so the answer is more likely to lie elsewhere.
Au contraire mon ami. That is precisely the time when alternatives should be reviewed in detail.However if one is seriously interested in working out what is going on (rather than promoting a never endable project) having arrived a what looks like a decent sized barrier to understanding it might be an idea to look for a way around it as well as banging one's head against it to see if it might fall over. Or, of course, they could just set up camp and wait, banners flying staring at the sky like Cargo Cultists.
plunker said:
PRTVR said:
plunker said:
PRTVR said:
plunker said:
Sceptics - it has been proffered that ocean cycles are behind the slowdown in warming and the implication is that warming will accelerate when the cycles flip the other way. Any comments on that, besides 'the models didn't predict it' (and 'Taxes!' and 'Asteroids!')?
For myself,as a non scientific person, it would appear as if it is just an excuse, things went wrong with the theory, so come up with an explanation for the pause, instead they should have looked at the original theory and questioned it validity, but most people know that would never happen, has anybody questioned the theory? plunker said:
Don't know where you get two decades from. The obs v models are running on the cool side since about 2006/7 I think last time I looked?
Clearly ocean cycles are important for understanding decadal climate variation, but it's not really clear that it matters to the bigger question of climate sensitivity for a doubling of CO2 and all that. They're trying to improve the models for decadal predictions I believe but it's a new endeavour - I'm pretty sceptical they'll make much headway.
I do like the "slightly cool" euphemism, would that be similar to Hurricane Andrew being slightly windy or the Japanese tsunami being choppy? You disagree with the IPCC on this point as regards divergence of models to observational data.Clearly ocean cycles are important for understanding decadal climate variation, but it's not really clear that it matters to the bigger question of climate sensitivity for a doubling of CO2 and all that. They're trying to improve the models for decadal predictions I believe but it's a new endeavour - I'm pretty sceptical they'll make much headway.
"In a presentation to the American Physical Society, William (Bill) Collins of Lawrence Berkeley National Laboratory and lead author of the modeling Chapter 9 of the IPCC AR5 said "Now, I am hedging a bet because, to be honest with you, if the hiatus is still going on as of the sixth IPCC report, that report is going to have a large burden on its shoulders walking in the door, because recent literature has shown that the chances of having a hiatus of 20 years are vanishingly small."
The lack of understanding of the global Climate mechanisms, be that C02 or Ocean cycles, would it not make sense to first get a better grip on the subject, before crying wolf on the "greatest threat facing mankind" (which it clearly is not) and spending trillions of £ on decarbonisation ?
This is the nub of the matter. The faithful in the media and elsewhere spouting 'the science is settled' yet the most cursory glance shows that it isn't. Politics rather than fact are driving the agenda I'm afraid. The euro farrago shows just how long those with an interest will persevere despite mounting evidence that they are wrong.
Ali G said:
Well CO2 absorbs photons - but only 15 micron photons. I presume the oversight was unintentional!
No. That statement implies that CO2 is absorbing at a single wavelength. It isn’t;
Ali G said:
Without doubt, there will be a proportion of CO2 molecules which will emit 15 micron photons - however, they probably will not.
I have no idea what you mean. At a given temperature a proportion of the CO2 molecules are emitting photons at any given point in time. Ali G said:
Even so - you are still left with the fact that the only 15 micron photons in the upper atmosphere will have been produced by CO2 molecules (i.e. NOT from the surface). And these are CO2 molecules which have been energised through collision with nearest neighbour molecules (probably N2).
Now, regardless of whether said photon goes up/down/left/right once generated, what does it do next?
I don’t understand your fixation with this. Yes, the vast majority of IR absorbed in the upper atmosphere is radiated by the atmosphere not by the surface. The amount of IR being emitted is temperature dependant. Absorbing IR raises the temperature above where it would be with no IR absorbtion. Now, regardless of whether said photon goes up/down/left/right once generated, what does it do next?
Emitted photons are either eventually absorbed by the atmosphere, absorbed by the surface or escape to space.
hairykrishna said:
I don’t understand your fixation with this. Yes, the vast majority of IR absorbed in the upper atmosphere is radiated by the atmosphere not by the surface. The amount of IR being emitted is temperature dependant. Absorbing IR raises the temperature above where it would be with no IR absorbtion.
Emitted photons are either eventually absorbed by the atmosphere, absorbed by the surface or escape to space.
So effectively all that happens is the wave path is extended for any individual photon - so given the speed of light how much delay would you say this causes? So max temp is arrived at maybe 2 ms earlier in any day and min temp maybe 2 ms later? Total energy = up, mean of midpoint temps in record = unchanged. Emitted photons are either eventually absorbed by the atmosphere, absorbed by the surface or escape to space.
What so you mean by temperature? Kinetic energy of Gases at near surface (where convection is king) or temperature of mass at surface (conduction/evaporation is king) or at TOA (where radiative transfer to space is king - except in case of escape veolocities)?
IR is temperature dependant but temperature is not IR dependant.
plunker said:
No you don't rip up atmospheric physics text books based on a few years of no warming - that's just wishful thinking on your part.
Nobodies going to rip up any text books because if you draw a linear trend through the temperature record from the beginning of the satellite era, with 95% confidence intervals, the ‘pause’ (i.e. slower warming) falls inside them easily. 2014 is bang on the trend line. As you’ve noted, it’s just short term variability. All of the stuff about ocean cycles is not major revision of a failing theory; it’s filling in details of an accurate one.
Jinx said:
So effectively all that happens is the wave path is extended for any individual photon
No. The emission characteristics of the earth are changed. The amount of IR radiated to space is reduced. This is an observed fact, predicted by theory. Where does that additional energy go?
PRTVR said:
But if we do not fully understand the effects of CO2 on the system, why is there a mad rush to remove man made CO2 from the system ?
We obviously have a different idea about what a mad rush looks like, but to briefly answer your question - because potential warming estimates give cause for concern.hairykrishna said:
No. The emission characteristics of the earth are changed. The amount of IR radiated to space is reduced. This is an observed fact, predicted by theory.
Where does that additional energy go?
State changes in H2O? Temperature gradiant over 24 hours? So many more ways than an increase in mean midpoint near surface kinetic energy. Only in a simplistic static system would you expect so see a temperature signal in the near surface mean midpoint data - and never in a atmosphere of a liquid/solid water planet. Where does that additional energy go?
Edited to question "The amount of IR radiated to space is reduced" - really? The only way that can happen is if the temperature is reduced! If we are measuring a drop in IR then the temperature of the earth has dropped!!!
Edited by Jinx on Thursday 5th March 11:03
QuantumTokoloshi said:
plunker said:
Don't know where you get two decades from. The obs v models are running on the cool side since about 2006/7 I think last time I looked?
Clearly ocean cycles are important for understanding decadal climate variation, but it's not really clear that it matters to the bigger question of climate sensitivity for a doubling of CO2 and all that. They're trying to improve the models for decadal predictions I believe but it's a new endeavour - I'm pretty sceptical they'll make much headway.
I do like the "slightly cool" euphemism, would that be similar to Hurricane Andrew being slightly windy or the Japanese tsunami being choppy? You disagree with the IPCC on this point as regards divergence of models to observational data.Clearly ocean cycles are important for understanding decadal climate variation, but it's not really clear that it matters to the bigger question of climate sensitivity for a doubling of CO2 and all that. They're trying to improve the models for decadal predictions I believe but it's a new endeavour - I'm pretty sceptical they'll make much headway.
"In a presentation to the American Physical Society, William (Bill) Collins of Lawrence Berkeley National Laboratory and lead author of the modeling Chapter 9 of the IPCC AR5 said "Now, I am hedging a bet because, to be honest with you, if the hiatus is still going on as of the sixth IPCC report, that report is going to have a large burden on its shoulders walking in the door, because recent literature has shown that the chances of having a hiatus of 20 years are vanishingly small."
The lack of understanding of the global Climate mechanisms, be that C02 or Ocean cycles, would it not make sense to first get a better grip on the subject, before crying wolf on the "greatest threat facing mankind" (which it clearly is not) and spending trillions of £ on decarbonisation ?
You've a strange way of supporting your two decades claim - quoting somebody talking about the future?
I'm not inclined to get into mitigation policy on the science thread.
hairykrishna said:
plunker said:
No you don't rip up atmospheric physics text books based on a few years of no warming - that's just wishful thinking on your part.
Nobodies going to rip up any text books because if you draw a linear trend through the temperature record from the beginning of the satellite era, with 95% confidence intervals, the ‘pause’ (i.e. slower warming) falls inside them easily. 2014 is bang on the trend line. As you’ve noted, it’s just short term variability. All of the stuff about ocean cycles is not major revision of a failing theory; it’s filling in details of an accurate one.
Have you noticed the PDO index flipped over hard positive last year btw?
http://research.jisao.washington.edu/pdo/PDO.lates...
Too soon to say of course but speculating is fun - some are suggesting the slowdown is over, we could get a double-dip El Nino this year (not that last years was a proper El Nino), and the possibility of back-to-back record-breaking years.
Jinx said:
Edited to question "The amount of IR radiated to space is reduced" - really? The only way that can happen is if the temperature is reduced! If we are measuring a drop in IR then the temperature of the earth has dropped!!!
Nope. For the system as a whole the incoming energy is, to a good approximation, fixed. The outgoing energy has reduced. The first law of thermodynamics tells us the temperature must rise until they balance.Adding IR active gases to the system means that the IR emission temperature is not equal to the surface temperature.
hairykrishna said:
Nope. For the system as a whole the incoming energy is, to a good approximation, fixed.
Has this been adjusted for albedo? Reflected energy doesn't stick around long enough.hk said:
The outgoing energy has reduced.
IR is temperature dependent - if IR has reduced then the temperature has reduced. Or is IR no longer temperature dependent?hk said:
The first law of thermodynamics tells us the temperature must rise until they balance.
Nonsense - the ratio of ice/water/vapour on a water planet is a better proxy for energy in the system - temperature (mean kinetic energy) will remain fairly constant until this ratio has changed. Laws of thermodynamics do not apply in systems with state changes. If I add enegy to melting ice what does it's temperature increase to?hk said:
Adding IR active gases to the system means that the IR emission temperature is not equal to the surface temperature.
The atmosphere (and all IR active gases within it) above Earth has a temperature profile of hot at the bottom - cold at the top - due to convection. If IR active gases made a difference within the atmosphere we would see a change to this profile. But again none of this will be seen in a near surface historical mean midpoint temperature record - energy has more degrees of freedom.hairykrishna said:
AA999 said:
I guess we could talk data data data all day long, but is the fact still so, that there still isn't a visible causality link to the human contribution within the data?
ie. a measured human input resulting in a measured global temperature output/change
There is. There’s a very accurately measured rise in CO2 concentration. This is directly attributable to fossil fuels due to it’s isotropic ratio. There’s a corresponding measured temperature rise.ie. a measured human input resulting in a measured global temperature output/change
If you don’t think this constitutes a “visible causality link” maybe you could explain exactly what does?
A measurable input with a measurable output, testable by anyone and everyone attaining the same results?
Its the part in bold from your reply which I struggle to accept though.
From a personal point of view I can accept that we can have a reasonable guess on human CO2 input in to the system but measuring the global temp increase, singling out that human input as the cause against the overwhelming competition of natural cycles/variations, is something that may be clutching at straws.
hairykrishna said:
I don’t understand your fixation with this. Yes, the vast majority of IR absorbed in the upper atmosphere is radiated by the atmosphere not by the surface. The amount of IR being emitted is temperature dependant. Absorbing IR raises the temperature above where it would be with no IR absorbtion.
Emitted photons are either eventually absorbed by the atmosphere, absorbed by the surface or escape to space.
Effectively, you have a circular argument - CO2 is both the only source of IR and the only sink - in the upper atmosphere (where H20 is largely absent).Emitted photons are either eventually absorbed by the atmosphere, absorbed by the surface or escape to space.
Now make a case that it is doing much at all, overall, other than being another mode of energetic interaction between molecules.
Re my earlier remark about probably not emitting - consideration needs to be given to CO2 colliding with nearest neighbour and converting vibrational energy to KE. Given mean time to collision is lower than decay time of vibrational state, it appears more likely that it will collide than emit. This may be controversial!
However, the fact of the matter is that observations do not stack up with expected outcomes, so something must be wrong with the hypothesis somewhere!
p.s. I note the large peak around 15 microns in the CO2 absorption spectrum - we both know what I meant - perhaps strongly absorbs around the 15 micron range of IR may have been a better way to phrase it.
Ali G said:
Effectively, you have a circular argument - CO2 is both the only source of IR and the only sink - in the upper atmosphere (where H20 is largely absent).
Now make a case that it is doing much at all, overall, other than being another mode of energetic interaction between molecules.
Re my earlier remark about probably not emitting - consideration needs to be given to CO2 colliding with nearest neighbour and converting vibrational energy to KE. Given mean time to collision is lower than decay time of vibrational state, it appears more likely that it will collide than emit. This may be controversial!
However, the fact of the matter is that observations do not stack up with expected outcomes, so something must be wrong with the hypothesis somewhere!
p.s. I note the large peak around 15 microns in the CO2 absorption spectrum - we both know what I meant - perhaps strongly absorbs around the 15 micron range of IR may have been a better way to phrase it.
Obvservations are actually stacking up reasonably well to my mind. CO2 concentration is up, so is temperature.Now make a case that it is doing much at all, overall, other than being another mode of energetic interaction between molecules.
Re my earlier remark about probably not emitting - consideration needs to be given to CO2 colliding with nearest neighbour and converting vibrational energy to KE. Given mean time to collision is lower than decay time of vibrational state, it appears more likely that it will collide than emit. This may be controversial!
However, the fact of the matter is that observations do not stack up with expected outcomes, so something must be wrong with the hypothesis somewhere!
p.s. I note the large peak around 15 microns in the CO2 absorption spectrum - we both know what I meant - perhaps strongly absorbs around the 15 micron range of IR may have been a better way to phrase it.
Either way, if there was a flaw with the theory I would bet my house that it's not in basic radiation transfer theory. It's been rigourously tested in the lab and in the atmosphere. Its theoretical basis is such that if it's wrong, so is the majority of modern physics.
Of course consideration needs to be given to collisions. This is how the energy from the IR absorption is thermalised. Energy that would have radiated to space if there was no absorption is instead ending up raising the energy of the lower atmosphere and, ultimately, the surface.
The concept of a lifetime of the state for emission is confusing you. It’s analogous to radioactive decay. They don’t have to spend X amount of time in the excited state before they emit, there’s a probability of emission per unit time. If there’s a proportion in the state, then some of that proportion are emitting photons in any given time interval. The amount of the population in the excited and state and therefore the amount of photons being emitted is dictated by the temperature.
hairykrishna said:
The concept of a lifetime of the state for emission is confusing you. It’s analogous to radioactive decay. They don’t have to spend X amount of time in the excited state before they emit, there’s a probability of emission per unit time. If there’s a proportion in the state, then some of that proportion are emitting photons in any given time interval. The amount of the population in the excited and state and therefore the amount of photons being emitted is dictated by the temperature.
It probably is not confusing me at all! I am quite familiar with the concept of half lives - hence why I myself stated 'probably' will not emit - although perhaps I should have stated that any one CO2 molecule probably will not - but with a population there will be a proportion which will.I am also fairly comfortable that radiative transfer is (probably) not in doubt.
However, for the enhanced greenhouse effect to work - there must be a proportion of IR which would be emitted to space were it not for the presence of CO2.
The source of IR must be:
(1) Surface of planet
(2) Atmosphere
For (2) I am fairly confident that neither N2 nor O2 will radiate IR - unless there is some phenomenon where IR is emitted through collision or KE since the vibrational states are not in IR range.
For CO2, which will emit, you must consider if this is energy which would be lost if CO2 were not present
. As a thought experiment, you could reduce CO2 to nil and consider if more/less or the same amount of energy would be lost to space - and what increasing the proportion would do? From my perspective, at the top of the troposphere, CO2 would be the cause for IR to be lost to space if it is the only generator of IR left. For CO2 to selectively pump more IR back to the surface than is lost to space would be nonsense imho - therefore IR generated within the atmosphere by CO2 should have a neutral effect on surface temps.For (1) A considerable proportion (an assumption) of relevant IR is absorbed in the lower trop through H20 and CO2. It is probable that in areas where CO2 does not absorb strongly, there will be wavelengths which will reach the upper atmosphere. This would appear to be sound logic, and these wavelengths should at some point be absorbed given sufficient CO2. However, this effect will eventually become saturated (if it hasn't already).
For what it's worth, I would not be surprised if there is still a modicum of additional warming to be had from CO2, but thermogeddon is not on the agenda!
Further head scratching has ensued, and since it is Friday. 
Consider a very simplified model of earth + atmosphere thought experiment.
We have surface + layer 1 atmosphere, layer 2 and layer 3.
We are only going to consider 15 micron photons, and CO2 molecules. All CO2 molecules fire synchronously 50$ up 50% down, and in layer 1 there are 8 molecules, layer 2 4 molecules and layer 3 2 molecules.
Step (1)
Surface fires 16 photons upwards.
Layer 1 fires 4 up to layer 2, 4 down to surface
Layer 2 fires 2 up to layer 3, 2 down to layer 1
Layer 3 fires 1 up to space, 1 down to layer 2
Result (net)
Surface fired 16 upwards, absorbed 4 - net 12 emitted upwards
Layer 1 received 16 from surface, emitted 8, received 2 from layer 2 absorbed 8 -
so net passed upwards 10
Layer 2 received 14 from layer 1 + surface, emitted 4, received 1 from layer 3 absorbed 4 - so net passed upwards 11
Layer 3 received 13 from layer 2 + surface, emitted 2, absorbed 2 so net passed upwards 11 + 1.
Surface temp now needs to increase so that overall 16 are still emitted to space to preserve equilibrium.
My arithmetic (and probably more) may be wrong.
Consider a very simplified model of earth + atmosphere thought experiment.
We have surface + layer 1 atmosphere, layer 2 and layer 3.
We are only going to consider 15 micron photons, and CO2 molecules. All CO2 molecules fire synchronously 50$ up 50% down, and in layer 1 there are 8 molecules, layer 2 4 molecules and layer 3 2 molecules.
Step (1)
Surface fires 16 photons upwards.
Layer 1 fires 4 up to layer 2, 4 down to surface
Layer 2 fires 2 up to layer 3, 2 down to layer 1
Layer 3 fires 1 up to space, 1 down to layer 2
Result (net)
Surface fired 16 upwards, absorbed 4 - net 12 emitted upwards
Layer 1 received 16 from surface, emitted 8, received 2 from layer 2 absorbed 8 -
so net passed upwards 10
Layer 2 received 14 from layer 1 + surface, emitted 4, received 1 from layer 3 absorbed 4 - so net passed upwards 11
Layer 3 received 13 from layer 2 + surface, emitted 2, absorbed 2 so net passed upwards 11 + 1.
Surface temp now needs to increase so that overall 16 are still emitted to space to preserve equilibrium.
My arithmetic (and probably more) may be wrong.
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