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Climate Change: History and Politics

Tim the plumber said:
So that would have about 110kg of water above every square meter (on average) in the form of vapor. Or 11cm of water over you as vapor, as an average.

You can see why the question as to how 0.4kg of CO2 would look like a small amount compared to this for some of us surely?
Click to expand...

400ppm would be 4 parts per 10,000 not 0.4; and that's by volume, so the mass ratio may be different. But yes, it does still look like a small amount, doesn't it? This is the biggest problem with amateurs pretending to know more than scientists. Why not go up to your doctor and tell him that a single drop of botulinum toxin is so tiny that it couldn't possibly hurt you?

The most depressing thing here is that I'm am amateur too - very much so - and yet the errors which I see self-described 'sceptics' making on this forum on a regular basis are often laughably simplistic even by my low standards. By my estimation Longview and Lord of Planar are the best this place has to offer, at least among regular contributors, and yet in this thread they appear utterly ignorant of concepts known in the 19th century and effectively proven in the 1950s!
 
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Mithrae said:
You're all over the place in a desperate attempt to defend the indefensible: Last post you insisted that we should look at a larger value for CH4 (the percentage increase above natural values) and now you're pleading that we must consider the larger value for CO2 (the total increase from human activities).

Yes, we've emitted a hundred times as much CO2... and it has had less than four times as much effect on the energy balance. By that metric, CH4 seems to be over 25 times as potent.

Our emissions of another thousand tonnes of CH4 has a much greater effect than another thousand tonnes of CO2. Foolishly (and not for the first time) I thought that your concerns might be genuine, but your ongoing attempts to slander the scientific community as using a "despicable scare tactic" - when it is abundantly clear that the stated facts are correct - suggest that this is (yet again) driven by some kind of ideological motivation rather than merely the sloppy thinking it first appeared to be.
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Wow.

It did go over your head, and I'm not going to try clarifying again at this time.
 
Mithrae said:
Near the surface yes, especially in tropical regions; though even Lord of Planar's graphs suggest regions around 3 and 8 micrometers where H2O's absorption is not complete which coincide with CH4 absorption peaks. But thermal emission doesn't stop at the planet's surface, and in the stratosphere water vapour is only marginally more abundant than methane. You can ignore or deny that 'til the cows come home, but it won't change the facts; you're hammering on with an objection which was answered six decades ago and has stood the test of time. Talk about flogging a dead horse :lol:
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Please cite a paper that shows sky emissions from methane, are anything but the minor trace.
Also please elaborate on what it is that you think was answered six decades ago?
 
Mithrae said:
Lord of Planar's graphs suggest regions around 3 and 8 micrometers where H2O's absorption is not complete which coincide with CH4 absorption peaks.
Click to expand...

Did you ever look at how little the RF power is of the thermal radiation in that band?
 
Mithrae said:
You're all over the place in a desperate attempt to defend the indefensible:
Click to expand...

Why is it indefensible to point out that such increases of CH4 are not realistic?
 
Lord of Planar said:
Why is it indefensible to point out that such increases of CH4 are not realistic?
Click to expand...

Because Mithrae suffers from the delusion that he is saving the planet through the power of hyperbole.
 
Lord of Planar said:
Why is it indefensible to point out that such increases of CH4 are not realistic?
Click to expand...

Your spiel began with Cabse's link explaining GWP as "a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time." I mentioned a thousand tonnes of CH4. And you're going to pretend that these are unrealistic numbers? I don't think there's even a word for this level of self-delusion.
 
longview said:
Please cite a paper that shows sky emissions from methane, are anything but the minor trace.
Also please elaborate on what it is that you think was answered six decades ago?
Click to expand...

As I'd already said and referenced in response to Cabse's question, the fact that the colder upper atmospheric layers have much less water vapour was known at the end of the 19th century, establishing the theoretical basis for a greenhouse contribution by other gases even in absorption bands which are saturated in the lower atmosphere; a possibility which was confirmed when computerised layer by layer calculations became available. CO2 was obviously the first gas of interest in that regard:

https://www.aip.org/history/climate/co2.htm

Still more persuasive was the fact that water vapor, which is far more abundant in the air than carbon dioxide, also intercepts infrared radiation. In the crude spectrographs of the time, the smeared-out bands of the two gases entirely overlapped one another. More CO2 could not affect radiation in bands of the spectrum that water vapor, as well as CO2 itself, were already blocking entirely.(8) . . . .

After Ångström published his conclusions in 1900, the small group of scientists who had taken an interest in the matter concluded that Arrhenius's hypothesis had been proven wrong and turned to other problems. Arrhenius responded with a long paper, criticizing Koch's measurement in scathing terms. He also developed complicated arguments to explain that absorption of radiation in the upper layers was important, water vapor was not important in those very dry layers, and anyway the bands of the spectrum where water vapor was absorbed did not entirely overlap the CO2 absorption bands. . . .


So even if water vapor in the lower layers of the atmosphere did entirely block any radiation that could have been absorbed by CO2, that would not keep the gas from making a difference in the rarified and frigid upper layers. Those layers held very little water vapor anyway. And scientists were coming to see that you couldn't just calculate absorption for radiation passing through the atmosphere as a whole, you had to understand what happened in each layer — which was far harder to calculate.

Digital computers were now at hand for such calculations. The theoretical physicist Lewis D. Kaplan decided it was worth taking some time away from what seemed like more important matters to grind through extensive numerical computations. In 1952, he showed that in the upper atmosphere, adding more CO2 must change the balance of radiation.(25)

But would adding carbon dioxide in the upper layers of the air significantly change the surface temperature? Only detailed computations, point by point across the infrared spectrum and layer by layer down through the atmosphere, could answer that question. By 1956, such computations could be carried out thanks to the increasing power of digital computers. The physicist Gilbert N. Plass took up the challenge of calculating the transmission of radiation through the atmosphere (he too did it out of sheer curiosity, as a diversion from his regular work making calculations for weapon engineers). He nailed down the likelihood that adding more CO2 would increase the interference with infrared radiation.​


The radiative forcing from CH4 changes between 1750 and 2011 is estimated at 0.48W/m^2 (+/- 0.05; IPCC AR5 WG1 Section 8.3.2.2).
IPCC AR5 WG1 Figure 8.15
Fig8-15.jpg
 
Mithrae said:
As I'd already said and referenced in response to Cabse's question, the fact that the colder upper atmospheric layers have much less water vapour was known at the end of the 19th century, establishing the theoretical basis for a greenhouse contribution by other gases even in absorption bands which are saturated in the lower atmosphere; a possibility which was confirmed when computerised layer by layer calculations became available. CO2 was obviously the first gas of interest in that regard:

https://www.aip.org/history/climate/co2.htm

Still more persuasive was the fact that water vapor, which is far more abundant in the air than carbon dioxide, also intercepts infrared radiation. In the crude spectrographs of the time, the smeared-out bands of the two gases entirely overlapped one another. More CO2 could not affect radiation in bands of the spectrum that water vapor, as well as CO2 itself, were already blocking entirely.(8) . . . .

After Ångström published his conclusions in 1900, the small group of scientists who had taken an interest in the matter concluded that Arrhenius's hypothesis had been proven wrong and turned to other problems. Arrhenius responded with a long paper, criticizing Koch's measurement in scathing terms. He also developed complicated arguments to explain that absorption of radiation in the upper layers was important, water vapor was not important in those very dry layers, and anyway the bands of the spectrum where water vapor was absorbed did not entirely overlap the CO2 absorption bands. . . .


So even if water vapor in the lower layers of the atmosphere did entirely block any radiation that could have been absorbed by CO2, that would not keep the gas from making a difference in the rarified and frigid upper layers. Those layers held very little water vapor anyway. And scientists were coming to see that you couldn't just calculate absorption for radiation passing through the atmosphere as a whole, you had to understand what happened in each layer — which was far harder to calculate.

Digital computers were now at hand for such calculations. The theoretical physicist Lewis D. Kaplan decided it was worth taking some time away from what seemed like more important matters to grind through extensive numerical computations. In 1952, he showed that in the upper atmosphere, adding more CO2 must change the balance of radiation.(25)

But would adding carbon dioxide in the upper layers of the air significantly change the surface temperature? Only detailed computations, point by point across the infrared spectrum and layer by layer down through the atmosphere, could answer that question. By 1956, such computations could be carried out thanks to the increasing power of digital computers. The physicist Gilbert N. Plass took up the challenge of calculating the transmission of radiation through the atmosphere (he too did it out of sheer curiosity, as a diversion from his regular work making calculations for weapon engineers). He nailed down the likelihood that adding more CO2 would increase the interference with infrared radiation.​


The radiative forcing from CH4 changes between 1750 and 2011 is estimated at 0.48W/m^2 (+/- 0.05; IPCC AR5 WG1 Section 8.3.2.2).
IPCC AR5 WG1 Figure 8.15
Click to expand...
And we are discussing Methane not CO2, The discussion in your cited paper is about CO2.
My point is that Methane absorption bands are in the same absorption bands as H2O, and the probability of a given ground emitted photon
striking an H2O molecule first, is many thousands of time greater than striking a methane molecule.
While the methane may exists at higher altitudes, where little water vapor is present, is irrelevant,
as the necessary wavelength has already been absorbed and remitted as some other longer wavelength, by H2O.
 
Mithrae said:
400ppm would be 4 parts per 10,000 not 0.4; and that's by volume, so the mass ratio may be different. But yes, it does still look like a small amount, doesn't it? This is the biggest problem with amateurs pretending to know more than scientists. Why not go up to your doctor and tell him that a single drop of botulinum toxin is so tiny that it couldn't possibly hurt you?

The most depressing thing here is that I'm am amateur too - very much so - and yet the errors which I see self-described 'sceptics' making on this forum on a regular basis are often laughably simplistic even by my low standards. By my estimation Longview and Lord of Planar are the best this place has to offer, at least among regular contributors, and yet in this thread they appear utterly ignorant of concepts known in the 19th century and effectively proven in the 1950s!
Click to expand...

Yes, 4kg per m2. Ugh.. it's been a long time since school.

Given that CO2 and water vapor are doing the same sort of thing why would the 4kg of CO2 be so much more important than the 110kg of water? And why would that job not be already done by the water?

I don't know the answer. It would be illuminating to hear the reason explained.
 
Origonally posted by Mithrae
Fig8-15.jpg


Given that shows a 2ish W/m2 of heating or about 2/3 of a degree c today at about 400 ppm CO2 a doubling to 800ppm CO2+all the rest should get to about +1.4c.

Given our present rate of CO2 output and the rise in it's concentration in the air that would be expected to come about in 200 years.

Is that about right?
 
longview said:
And we are discussing Methane not CO2, The discussion in your cited paper is about CO2.
My point is that Methane absorption bands are in the same absorption bands as H2O, and the probability of a given ground emitted photon
striking an H2O molecule first, is many thousands of time greater than striking a methane molecule.
While the methane may exists at higher altitudes, where little water vapor is present, is irrelevant,
as the necessary wavelength has already been absorbed and remitted as some other longer wavelength, by H2O.
Click to expand...

Once again, thermal emission doesn't stop at the planet's surface :roll: Any substance with a temperature above absolute zero emits thermal radiation; the surface to the troposphere as well as the troposphere to the stratosphere.

You're going to have to do a lot better than this if you hope to overturn scientific conclusions which have been well-established for decades. Or do you really think that everyone should just accept your say-so that all the IPCC reports over the decades, all the papers they draw on and all the scientific sources which list CH4 as the second-most important long-lived greenhouse gas are all somehow missing a wildly obvious point which your simplistic analysis has revealed?
 
Mithrae said:
Once again, thermal emission doesn't stop at the planet's surface :roll: Any substance with a temperature above absolute zero emits thermal radiation; the surface to the troposphere as well as the troposphere to the stratosphere.

You're going to have to do a lot better than this if you hope to overturn scientific conclusions which have been well-established for decades. Or do you really think that everyone should just accept your say-so that all the IPCC reports over the decades, all the papers they draw on and all the scientific sources which list CH4 as the second-most important long-lived greenhouse gas are all somehow missing a wildly obvious point which your simplistic analysis has revealed?
Click to expand...
Thermal emissions are represented by photons, and photons must obey the laws of physics.
If a photon strikes and atom or molecule that absorbs at the wavelength of the photon,
The energy in the photon is absorbed, and the atom or molecule moves to a higher energy state.
Based on the atomic structure, the energy state the decays by way of spontaneous emission, throwing off
other (lower energy mostly) photons (and RF)as it steps back towards it's ground state.
H2O, like CO2, has many small steps in it's path to ground state.
The re emissions from H2O could be the original wavelength, but it is unlikely, The much more likely possibility
is a collection of longer wavelengths and possibly some RF.
The only requirement, is that the total energy out, must equal the total energy in.
If you can find an IR sky spectrum, showing prominent CH4 IR lines, I would like to see.
 
Tim the plumber said:
Yes, 4kg per m2. Ugh.. it's been a long time since school.

Given that CO2 and water vapor are doing the same sort of thing why would the 4kg of CO2 be so much more important than the 110kg of water? And why would that job not be already done by the water?

I don't know the answer. It would be illuminating to hear the reason explained.
Click to expand...

Then read the last two pages of the thread.

Tim the plumber said:
Given that shows a 2ish W/m2 of heating or about 2/3 of a degree c today at about 400 ppm CO2 a doubling to 800ppm CO2+all the rest should get to about +1.4c.

Given our present rate of CO2 output and the rise in it's concentration in the air that would be expected to come about in 200 years.

Is that about right?
Click to expand...

If memory serves on the present increasing trajectory we'll hit 560ppm in 50 years, give or take, so 800ppm would be not much more than a century away. From that CO2 alone, 1.4C increase before any feedbacks probably isn't too far off the mark.
 
longview said:
Thermal emissions are represented by photons, and photons must obey the laws of physics.
If a photon strikes and atom or molecule that absorbs at the wavelength of the photon,
The energy in the photon is absorbed, and the atom or molecule moves to a higher energy state.
Based on the atomic structure, the energy state the decays by way of spontaneous emission, throwing off
other (lower energy mostly) photons (and RF)as it steps back towards it's ground state.
H2O, like CO2, has many small steps in it's path to ground state.
The re emissions from H2O could be the original wavelength, but it is unlikely, The much more likely possibility
is a collection of longer wavelengths and possibly some RF.
The only requirement, is that the total energy out, must equal the total energy in.
If you can find an IR sky spectrum, showing prominent CH4 IR lines, I would like to see.
Click to expand...

I've already shown you (several times) the reason why tropospheric saturation of particular absorption bands by water vapour doesn't preclude other gases' greenhouse contribution at higher altitudes, and referenced the most recent IPCC estimate for the particular contribution of methane. (LoP also cited the AR4 figures earlier.) At this point I don't know whether you're being deliberately obfuscationary or if you still really don't understand the issue; based on past experience it could easily be either. But that's honestly the most I can do for you. Like you, I am an amateur as I've already said - I think I understand barely enough to see why the scientists are correct, but certainly not enough to write 'Radiative Transfer Equations for Dummies' :lol:

I wonder if you can cite even a single peer-reviewed study from the past quarter century which supports your amateur claim that methane emissions have no greenhouse effect?
 
Mithrae said:
I've already shown you (several times) the reason why tropospheric saturation of particular absorption bands by water vapour doesn't preclude other gases' greenhouse contribution at higher altitudes, and referenced the most recent IPCC estimate for the particular contribution of methane. (LoP also cited the AR4 figures earlier.) At this point I don't know whether you're being deliberately obfuscationary or if you still really don't understand the issue; based on past experience it could easily be either. But that's honestly the most I can do for you. Like you, I am an amateur as I've already said - I think I understand barely enough to see why the scientists are probably correct, but certainly not enough to write 'Radiative Transfer Equations for Dummies' :lol:

I wonder if you can cite even a single peer-reviewed study from the past quarter century which supports your amateur claim that methane emissions have no greenhouse effect?
Click to expand...
The spectrum lines must be present for it to have any effect, it may have a minor effect.
Can you cite a peer reviewed study that shows they actually can detect the IR emission lines CH4 in the atmosphere.
Here is a Sky spectrum from that range, from
Gran Telescopio CANARIAS
TelescopeEsmissivity_005.png

Can you see the 3.3 and the 7.7 um lines in there?
It could be somewhere in all that H2O noise.
 
Mithrae said:
Then read the last two pages of the thread.



If memory serves on the present increasing trajectory we'll hit 560ppm in 50 years, give or take, so 800ppm would be not much more than a century away. From that CO2 alone, 1.4C increase before any feedbacks probably isn't too far off the mark.
Click to expand...

ESRL Global Monitoring Division - Global Greenhouse Gas Reference Network

Looks like a fairly straight line at +2.5 ppm/yr to me so 400ppm increase should take 160 years, at current trend. To get to +1.4c over now. Quick run for the hills!!
 
Tim the plumber said:
Origonally posted by Mithrae
Fig8-15.jpg


Given that shows a 2ish W/m2 of heating or about 2/3 of a degree c today at about 400 ppm CO2 a doubling to 800ppm CO2+all the rest should get to about +1.4c.

Given our present rate of CO2 output and the rise in it's concentration in the air that would be expected to come about in 200 years.

Is that about right?
Click to expand...

The thing the alarmists will never admit about that forcing chart is that, even if accurate, the two aerosol entries uncertainty level reduces AGW to nothing more than a WAG.
 
Mithrae said:
Your spiel began with Cabse's link explaining GWP as "a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time." I mentioned a thousand tonnes of CH4. And you're going to pretend that these are unrealistic numbers? I don't think there's even a word for this level of self-delusion.
Click to expand...

It's unrealistic to cite such low emissions to imply realistic warming follows the same trend. Especially when the math has the warming of both at those levels so insignificant.

Increased for each ppb decrease as the levels already in the atmosphere increase. It is unrealistic to apply a straight line slope on a log curve.

Again, it is the perception that people who don't understand the log nature get. They The pundits use ignorance to imply the dramatic levels hold for future increases. They don't.

I thought you were better than agreeing with such trickery science.
 
Mithrae said:
It certainly does seem appropriate here :(
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Facts are not denial. My opinion of what the metric does for science is not a denial. I factually agree the metric shows as said in the science. Just that the metyric has no meaningful purpose, except as a scare tactic, under real increases.
 
Mithrae said:
If memory serves on the present increasing trajectory we'll hit 560ppm in 50 years, give or take, so 800ppm would be not much more than a century away. From that CO2 alone, 1.4C increase before any feedbacks probably isn't too far off the mark.
Click to expand...

Is that a linear trajectory?

You know, as the partial pressure equilibrium in the atmosphere vs. the seas gets larger, the velocity of absorption also gets larger.

Linear projections are bad science for that many years out.
 
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Lord of Planar said:
Facts are not denial. My opinion of what the metric does for science is not a denial. I factually agree the metric shows as said in the science. Just that the metyric has no meaningful purpose, except as a scare tactic, under real increases.
Click to expand...

To add...

When using equal mass instead of equal volume, you are adding 3.75 times more CH4 than CO2 in volume. 3.75 times more carbon!

CO2 is more than 5 times stronger than CH4 using equal volumes of each.
 
Lord of Planar said:
To add...

When using equal mass instead of equal volume, you are adding 3.75 times more CH4 than CO2 in volume. 3.75 times more carbon!

CO2 is more than 5 times stronger than CH4 using equal volumes of each.
Click to expand...

Once again, a flat-out lie. You yourself posted earlier that A) atmospheric CH4 had increased by ~1ppm above preindustrial levels, well under one hundredth of the CO2 increase and B) the estimated forcing from that increase was ~0.48W/m^2, well over one fourth of the CO2 forcing. Even given that the first ppm CO2 increase above natural levels had a greater effect than the 120ppm average, we're still obviously looking at somewhere in the order of 20 times greater forcing effect from 1ppm of methane than of carbon dioxide.
 
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