Re: AGW. LNG Worse Than Coal.

Robert Carnegie wrote:

On 05/11/2024 01:13, Cryptoengineer wrote:

On 11/4/2024 4:34 PM, Robert Carnegie wrote:

On 30/10/2024 01:37, Cryptoengineer wrote:

I'd like to see some numbers on this.
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Yes, burning methane generates less CO2 per BTU than
methane.
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But:
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A significant amount of methane escapes the system in leaks
and gets into the atmosphere without being burnt. In the US,
about 1.4%. Other countries do much worse, and a recent satellite
has started mapping the problem:
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https://www.msn.com/en-us/money/other/nasa-s-methane-satellite-just- mapped-its-first-plumes/ar-AA1spd3X?ocid=BingNewsSerp
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Coal that 'leaks' out of the system just sits on the ground.
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AND
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Methane, molecule for molecule, is a far more potent greenhouse
gas than CO2. 120x as potent, in fact.
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This is mitigated by the fact that methane only  lasts about 10
years in the atmosphere, while CO2 lasts far longer.
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https://www.epa.gov/ghgemissions/understanding-global-warming-potentials >
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So, I'd like to see some actual numbers to support of debunk this
claim, not a simple declaration.

>
I understand that methane in the sky is slowly
converted to CO2.

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Yes, and far faster then CO2 gets recycled. But it's also a far
more portent as a greenhouse gas, pound for pound, as C02. Numbers
matter, and figuring out the relative contribution of each to
warming \caused is a non-trivial calculation.

 I wanted to make the point that the increase of
methane in the atmosphere means that CO2 in the
atmosphere increases as well.
 Another thing - I heard an argument, which may
be completely wrong, or even right but irrelevant,
that a certain level of CO2 blocks heat radiation
from,the surface by about 100% at relevant infrared
wavelengths.  That seems to imply that more CO2
stops getting worse then

This is the saturation argument, which has been discussed here.  The easiest way to see that it is incorrect is to note that absorption is nowhere near 100% over most of the spectrum.
However, there is some effect, as the warming is not linear in CO2 but logarithmic. So going from 2X to 4X has the same impact as going from 1X to 2X, or 10X to 20X, and so on.
  - however, it may be enough

to remove humans ultimately as owners of the Earth,
and also of course it makes getting CO2 down to
a tolerable value that much harder.  I'm bringing
it up because...  does CH4 affect other wavelengths
of heat radiation which are passed through by CO2?
So that it makes a possible "couldn't be worse" CO2
situation, worse?

The photons absorbed by greenhouse gases cause the molecules to rotate and vibrate.  As a linear molecule O=C=O carbon dioxide doesn't have as many available modes of rotation-vibration as do more irregularly shaped molecules such as H2O and CH4. So a small amount of Methane has a high absorption cross section relative to CO2.
Luckily, however, Methane does not absorb in as broad a range of frequencies as CO2.  Unluckily, it peaks in areas where CO2 doesn't absorb strongly.
The X value in "Methane is X times worse than Carbon Dioxide" varies wildly from source to source.  I think a lot of it is being taken out of context.  The full-spectrum value I heard of years ago is X=25.  Which is quite bad enough.
A standard figure describing the absorptivity of various gases can be found in most textbooks on the subject, and here:
https://www.e-education.psu.edu/meteo3/sites/www.e-education.psu.edu.meteo3/files/images/lesson3/absorptivity0304.png
William Hyde