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An interesting comment at Neven's theorizes that Aug & Sept CH4 levels pack additional punch in the Arctic because the low solar angle forces photons through much more of the GHG polluted atmosphere. 

Terry

It seems that CH4 would be spectrally active more as reradiation in the IR, thus solar radiation (and its angle) wouldn't much of a direct factor? CH4 does absorb some of the shortwave IR radiation coming from the sun though around 3 microns, so here it could have an effect, though I'm unsure which sign it has.

 

On another note, I've seen a skeptical argument that methane has less effect when water vapor is present, since they absorb/emit at some of the same wavelengths. What's the story on that? I suppose that the absorption isn't saturated enough, thus increases in each of these gases remains important.

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Enormous mounds of methane found under the Arctic sea: Underwater pingos may reveal 'worrying' clues about climate change

http://www.dailymail.co.uk/sciencetech/article-3325230/Enormous-mounds-methane-Arctic-sea-Underwater-pingos-reveal-clues-climate-change.html

 

Huge mounds filled with methane have been discovered forming on the frozen sea bed of the Arctic Ocean, raising fears they are being caused by climate change.

Scientists fear thawing permafrost beneath the ocean is causing methane to become free, forming underwater pingos - mounds of earth and ice - off the coast of the Yamal Peninsula in Siberia.

Similar structures are thought to be behind enormous craters that have appeared on the land on the peninsula as methane exploded out of the Earth.

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Already, the ruptured storage facility has released well over the equivalent of 800,000 metric tons of carbon dioxide – about the same amount that would be generated by driving 160,000 cars for a year, according to the California Air Resources Board.

 

 

I'm guilty of it as are most of you, but I'm sick of burning dead plant material and gases.

 

Can we simply take half the military budget and divert that to solar/wind farms and end this nonsense?

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Already, the ruptured storage facility has released well over the equivalent of 800,000 metric tons of carbon dioxide – about the same amount that would be generated by driving 160,000 cars for a year, according to the California Air Resources Board.

 

 

I'm guilty of it as are most of you, but I'm sick of burning dead plant material and gases.

 

Can we simply take half the military budget and divert that to solar/wind farms and end this nonsense?

That'd work for me. Might even get that money back in the long run through reduced pushback to interventionist foreign policy. Combo it with a fee and dividend plan and let the market boost it too.

 

As bad as that leak is, it's a drop in the bucket compared to the 20 million barrels per day of oil we burn currently.

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Yeah, and this is the bracketed piece of crap the negotiators have produced so far:

 

http://unfccc.int/files/bodies/awg/application/pdf/draft_paris_outcome_rev_5dec15.pdf

 

It's better than Copenhagen, but that's not saying much. 1 week left. Not sure how they're going to come up with an agreement with any real teeth.

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On 6/11/2015 at 1:52 PM, salbers said:

It seems that CH4 would be spectrally active more as reradiation in the IR, thus solar radiation (and its angle) wouldn't much of a direct factor? CH4 does absorb some of the shortwave IR radiation coming from the sun though around 3 microns, so here it could have an effect, though I'm unsure which sign it has.

 

On another note, I've seen a skeptical argument that methane has less effect when water vapor is present, since they absorb/emit at some of the same wavelengths. What's the story on that? I suppose that the absorption isn't saturated enough, thus increases in each of these gases remains important.

That’s right - as far I understood. CH4 absorbs very strongly  … the 3.5 and 8 micron WL almost quite specifically, and very efficiently, which are in the IR

That said … the suns total spectral light carries IR along with all else - I’m curious what was meant 

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On 9/4/2021 at 10:32 PM, Typhoon Tip said:

That’s right - as far I understood. CH4 absorbs very strongly  … the 3.5 and 8 micron WL almost quite specifically, and very efficiently, which are in the IR

That said … the suns total spectral light carries IR along with all else - I’m curious what was meant 

methane needs to be tightly controlled, we have 5% coming from methane leaks during fracking (one reason we banned it in NY) and the other thing is to limit animal farming (both for the benefit of the planet and for our own health).  Methane is 86X more efficient as a GHG than CO2 is.

 

 

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5 hours ago, A-L-E-K said:

how is it not over if we are already at the point where we can't control runaway microbial driven ch4 emissions 

https://www.nature.com/articles/d41586-022-00312-2

 

Still more research to be done here, but the proportion of light (carbon 13 depleted), biogenic methane seems to be increasing. The rise and fall of methane: Line chart showing the proportion of methane containing the isotope carbon-13.

 

That's a big regime change from the pre-2005 era, going back to the Industrial Revolution-- where carbon-13 enriched CH4 was on a steady increase. While the research linked in the article wasn't conclusive, it does suggest that most of that increase in the last several years is microbial, and the NH/SH gradient in obs is best replicated when you assume it's coming from equatorial tropical and SH wetlands. That ~85% of this increase is likely microbial since 2005/06 is worrying. It doesn't debunk that it could have come mainly from an increase in FF extraction, but that theory is taking on water now, imo. It's much harder to do anything about wetland emissions -- and if this represents a significant feedback from increasing temp and rainfall, then that represents a world of hurt. Not sure how much higher those emissions can go, since a move of this magnitude wasn't really expected -- even the higher end scenarios I don't think had this kind of response until much later in the century.

Gonna be doing a lot more digging on this in the next few days.

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Relevant:

Methane release from carbonate rock formations in the Siberian permafrost area during and after the 2020 heat wave

Quote

To conclude, our observations hint at the possibility that permafrost thaw does not only release microbial methane from formerly frozen soils but also, and potentially in much higher amounts, thermogenic methane from reservoirs below and within the permafrost. As a result, the permafrost–methane feedback may be much more dangerous than suggested by studies accounting for microbial methane alone

 

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Here are the updated radiative forcing equations from Etminan et al. 2016. Note that Myhre (of 5.35 * ln(C/C0) fame) is an author on this publication. The formula with minor coefficients removed for CH4 is 0.043 * (√M - √M0). For example an increase from 1900 ppb to 2500 ppb is expected to produce 0.043 * (√2500 - √1900) = +0.27 W/m2 of RF.

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1 hour ago, bdgwx said:

Here are the updated radiative forcing equations from Etminan et al. 2016. Note that Myhre (of 5.35 * ln(C/C0) fame) is an author on this publication. The formula with minor coefficients removed for CH4 is 0.043 * (√M - √M0). For example an increase from 1900 ppb to 2500 ppb is expected to produce 0.043 * (√2500 - √1900) = +0.27 W/m2 of RF.

Thanks for that -- that comes out to an additional 0.15-0.25C of warming at equilibrium, if I did my math right. Not insignificant.

Doing some additional reading. Other potential causes so far:

Reduction in ocean shipping SO2 by 80% due to progressive sulfur fuel content regulations (including new 2020 IMO regulations) regarding bunker fuel. This would reduce cloud cover and dimethylsulfide (DMS) removal by cloud processes, reducing available OH to sink methane emissions. This is a potential issue in its own right even without considering methane effects, with some considerable uncertainty as of now -- ranging from a fairly small effect (0.05W/m2) to a relatively huge one (up to 0.5W/m2), large enough to produce a termination shock on its own, or a coupled one when combined with methane effects. More data and study needed on that one for sure. However, I would note that CERES has detected a large energy imbalance of absorbed solar radiation over the NPAC and NATL over the last few years.

 

CO2 fertilization causing an increase in net primary productivity (NPP), which would also increase microbial methane emissions.

 

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1 hour ago, csnavywx said:

Thanks for that -- that comes out to an additional 0.15-0.25C of warming at equilibrium, if I did my math right. Not insignificant.

Doing some additional reading. Other potential causes so far:

Reduction in ocean shipping SO2 by 80% due to progressive sulfur fuel content regulations (including new 2020 IMO regulations) regarding bunker fuel. This would reduce cloud cover and dimethylsulfide (DMS) removal by cloud processes, reducing available OH to sink methane emissions. This is a potential issue in its own right even without considering methane effects, with some considerable uncertainty as of now -- ranging from a fairly small effect (0.05W/m2) to a relatively huge one (up to 0.5W/m2), large enough to produce a termination shock on its own, or a coupled one when combined with methane effects. More data and study needed on that one for sure. However, I would note that CERES has detected a large energy imbalance of absorbed solar radiation over the NPAC and NATL over the last few years.

 

CO2 fertilization causing an increase in net primary productivity (NPP), which would also increase microbial methane emissions.

 

If the problem regarding absent negative feedbacks is really that severe not only do the ocean's have more room to heat (forcing in the pipeline) but also do it more rapidly.

Ocean heat uptake is poorly misunderstood especially by the public. 98% of the additional radiative forcing goes into the ocean and the remainder land regions and ice caps. This may be a rare instance where I suggest geoengineering as the problem appears to be very severe and an extinction event in it's own right (first in the seas and spreading onto land).

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On 2/10/2022 at 11:04 PM, Vice-Regent said:

If the problem regarding absent negative feedbacks is really that severe not only do the ocean's have more room to heat (forcing in the pipeline) but also do it more rapidly.

Ocean heat uptake is poorly misunderstood especially by the public. 98% of the additional radiative forcing goes into the ocean and the remainder land regions and ice caps. This may be a rare instance where I suggest geoengineering as the problem appears to be very severe and an extinction event in it's own right (first in the seas and spreading onto land).

Yep, most of that additional heat will go into the oceanic flywheel for later. Just didn't expect that level of additional forcing so quickly. I expect we'll feel some of that on the next Nino, for instance.

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On 2/12/2022 at 3:46 PM, csnavywx said:

Yep, most of that additional heat will go into the oceanic flywheel for later. Just didn't expect that level of additional forcing so quickly. I expect we'll feel some of that on the next Nino, for instance.

There is a double whammy as aerosol emissions decrease in China and other developing countries, which also increases forcing.  The good news:  methane emission reductions would have a rapid impact due short lifetime.  We should be using methane reductions to offset the forcing boost from reduced aerosols.

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9 hours ago, chubbs said:

There is a double whammy as aerosol emissions decrease in China and other developing countries, which also increases forcing.  The good news:  methane emission reductions would have a rapid impact due short lifetime.  We should be using methane reductions to offset the forcing boost from reduced aerosols.

It would -- though it's not clear that we're going to get any help from nature now if microbial sources are indeed increasing, especially if it's a result of warming temperatures over tropical wetlands. That could be a tipping point mechanism.

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