Can we deliberately increase #methane destruction by OH radicals?
In the Northern mid to high latitudes #CH4 concentration near ground is the highest. 2200ppb is not a rare event in #ICOS measuring stations around Europe.
So deploying our radicals would be more efficient there.
What do we already have that has NOx aplenty and can be bombarded with UV to create OH?
Maybe every greenhouse in the Netherlands.. Oh, is UV and ozone bad for plants? Ozone is the step between NOx and OH.

Workers in the greenhouses would have to wear WW2 gas masks and full body lead suits, would they not...
uhm.
So better no UV in a walled-in room like a greenhouse.

In case UV is not bad for plants,

we can fasten UV lights underneath #agriPV where wind dissipates the toxic ozone !
And where wind also automatically replenishes CH4 and NOx.

And for maximum usefulness, the UV lights are cased in with a thin wire mesh on which the water vapour can condensate that is a byproduct of the CH4 bombing. The droplets are then channelled into ground water. Or pipelined to Southern Europe.

Ah. even better.
AgriPV with UV underneath directly in Southern Europe, where the harvested water can also be used directly.
#anloCH4 #anloOH

OH radicals are born if NOx is hit by UV radiation in sunlight. (And water vapour in the air reduces this OH-birthing process, see posts above.) OH Radicals only have a very short lifetime of less than a few seconds because they bomb anything to bits that comes their way, or rather, they react with anything in their neighborhood. If a #methane molecule is bombed by OH radicals, the result is water vapour and CO2.

NOx is born in cow and pig shit, in artificial fertilizer, and also in high-heat combustion processes like lightening strikes, forest fires, and cars, trucks, planes, and ships.

NOx and the chemicals born when NOx is hit by UV sunlight (eg ozone), are harmful to living beings. So anthropogenic NOx gets reduced technologically after national and regional #CleanAir regulations. And by the international shipping organisation IMO, see eg https://www.ukpandi.com/news-and-resources/articles/2022/imo-tier-iii-nitrogen-oxide-nox-emission-compliance/ It also describes some techy ways for reducing NOx emissions during fuel combustion.

IIUC, #diesel engines burn fuel at higher heat than Otto motors. This makes diesel motors more efficient, leading to less CO2 emissions per km – but to more #NOx. Which must then be scrubbed from the exhaust.

We all recall the two (!) diesel scandals 2004 and 2015 where European car industry was found to cheat deliberately wrt NOx from diesel. (Cheating isn't the right word when you consider that people get sick and die from NOx' ozone pollution. Hence the regulations. And people with the car industry know this – so their cheating is really murder according to German law and recent verdicts [on other cases but with similar circumstances relevant to the legal definition of #murder].
The fact that German state attorneys chose to only prosecute the fraud speaks volumes wrt how car-centred their minds work. IMO, those managers and engineers should spend their lives in a prison cell. #Dieselgate #CleanDiesel Together with the software manufacturers at #Bosch, and the Rex Tillersons of this world. #ExxonKnew
Murderous cheating wrt Otto motors is also known https://de.wikipedia.org/wiki/Abgasskandal#Manipulation_bei_Fahrzeugen_mit_Ottomotoren
Here it is a software for reducing #CO2 emissions on the testing stand. )

Anyway. Where was I?
Ah, yes, the NOx-creation process and how these give birth to OH radicals in UV sunlight: OH radicals are born when UV sunlight hits NOx molecules. After only a few seconds, the suicidal radical bombs a suitable molecule like methane. But new radicals are born all day long. Because NOx is replenished constantly, in lightening strikes, forest fires, burning fossil fuels in🏭🏠, and:🚗🚚✈️🚢

Together with the new finding that more moisture in the air due to global warming reduces UV sunlight, and hence reduces the births of OH radicals, which in turn increases CH4 lifetime https://www.science.org/doi/10.1126/science.adn0415 #Prather et al 2024🔒
I have been also wondering for a few years now whether NOx regulations and technological scrubbing (where it does occur, harr harr), and also a serious electrification in transport, industry and homes already have, and will have later on, a sufficiently large effect on increasing CH4 lifetime.

And I am wondering again whether a reduced NOx abundance during the warm=wet and less fire-prone, stronger forested #Miocene caused CH4 to linger for longer because fewer OH radicals were born.
Adding the new finding to this theory, that more water vapour decreases OH concentration, makes my theory even more pertinent:
With high temperatures during the miocene at surprisingly low CO2 values, methane could explain parts of the discrepancy. But we don't have proxies for methane concentration.
Kind of important because today's climate sensitivity for doubling CO2 = 3°C, is in part fed by findings in #paleoclimate such as the Miocene.

The Miocene had a different land mass layout, different ocean currents, and also different biomes, hydrological cycle and whatnot.
So it's not a good analog for our experiment today as I often point out, eg in this thread https://climatejustice.social/@anlomedad/112767092856263574
It's also mentioned in passing in Gavin Schmidt's new blog post about the paper that had prompted my thread above, with its spurious claim of climate sensitivity. https://www.realclimate.org/index.php/archives/2024/08/oh-my-oh-miocene/#ITEM-25598-4

So these system setting differences explain part of the temperature/CO2 discrepancy.
But not all.
#anloCH4 #anloOH

The study on how increased water vapour reduces the concentration of OH radicals by filtering UV-light, and thus,
extending the lifetime of #methane in the #atmosphere: https://www.science.org/doi/10.1126/science.adn0415 🔒
#Prather et al 2024 "Resetting tropospheric OH and CH4 lifetime with ultraviolet H2O absorption"

A side note:
The suggested replacement of hard-to-abate fossil fuels with hydrogen in steel industry or shipping, makes the discovery of the connection
water vapour ↘️ OH radicals ↗️ CH4 lifetime

even worse.
Considering that #climateChange increases methane emissions from natural sources due to more wetlands and thawing permafrost becoming active peat land,
we're all the more dependent on OH radicals bombing CH4 molecules to bits.

But the leaky supply chain of hydrogen will further increase water vapour – by also using up OH radicals for this reaction – hence, serious use of hydrogen in industry or heavy transport will further decrease OH concentration,

which is already decreasing due to warmer air holding more moisture, as the study apparently shows. #Openaccess should be mandatory!!
#anloCH4 #anloOH

This new paper actually prompted me to ponder and calculate potential methane levels in the mid #Miocene 15Ma.
https://www.nature.com/articles/s41467-024-47676-9 "Continuous sterane and phytane δ13C record reveals a substantial pCO2 decline since the mid-Miocene" by #Witkowski etal 2024.

The paper made the rounds on Twix and in the Fediverse because it is taken as proof that "IPCC was wrong AGAIN and ECS is far higher than their 3°C ±1!"

As it happens, the authors themselves write that they a) used a different formula to calculate their ECS and b) that they did not incorporate methane and cloud feedbacks and that this omission likely is the reason for paleoclimate ECS being always higher than ECS base on today's boundary conditions.

Looking at CO2 values in their supplementary Excel file, the question must be raised how on Earth they can muster the audacity to claim they had proven IPCC ECS wrong – with 3 data points in 15Ma for one proxy and the other one has a single data point...
I mean... really... the individual proxy series in Hoenisch's paleoCO2-archive are mostly equally spotty. Only in averaging them all, and with properly equal regional distribution, can one hope to come near CO2 levels in the distant climate past. One study is not enough to conclude anything.

Also maybe their sediment core from the Californian continental shelf in shallow waters... was an upwelling zone 15Ma? Different Pacific currents due to open Panama Isthmus and the Pacific not flowing into the Arctic Sea make that possible, no?
d13C as proxy for CO2 from upwelling zones is known to be too high because of the additional nutrients those creatures received that later form the sediment proxy. (See supplement to Hoenisch )

Also maybe: the location was a melting zone for hydrates in the warm Mid Miocene 15Ma?
It looks shallow enough for warming waters to reach down and melt the iced gas. And would this dissolved CH4 become accessible carbon for the creatures?

Dunno. Anyway.
That's why I sat down and guesstimated and calculated the methane level in 15Ma. 😁
#FridaysForFuture
#anloCH4

But do I think that with #Exxon 's CO2-experiment we can reach #methane levels of the middle Miocene?

No. Not if civilisation continues.

The forest cover is missing for setting the hydrological cycle in continental interiors as high as
to allow for 10 times more wetlands than today.

The #Miocene really isn't a good analog for future climate in high emission pathways at all. Apart from the missing biomes & methane, lots of other important, climate-relevant changes occurred since due to tectonics:

The #Arctic sea didn't get #Pacific waters at all. But the tropical Pacific got #Atlantic waters via wide open Panama Isthmus.
The Rockies , the Andes, and the Alpes were much, very much lower, the Alpes by maybe 2km.

The ENSO4 region near Papua Guinee and Australia was totally different due to PNG and AUS being that much further South, 10° or so.
The mountain ranges in China's Northwest & Mongolia weren't there.
The Arab Peninsula didn't exist. The Mediterranean was larger.

See maps below, from a paper in the special Miocene Issue, https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021PA004298 #He et al 2021, "Middle Miocene (∼14 Ma) and Late Miocene (∼6 Ma) Paleogeographic Boundary Conditions".

All these things not only influenced but determined atmospheric and ocean currents! So just because global °C might be the same on paper ( which it wouldn't be, see impossible-to-achieve methane levels and vastly different hydrological cycle), the climate reality would NOT be the same at all.

A climate analog for #Exxon's CO2 experiment can only be taken from interglacials up to 1 million years ago when the major Earth system settings were really like today's. And if we find ourselves outside their boundaries then it's simply that: unchartered territory.

Promoting a false analog as example for what the world might come to also leads to wrong conclusions for example regarding adaption. I don't see any value in talking o the Miocene as climate analog, only negative impacts.
#anloCH4

How do the assumed-guessed
+5.1°C in the mid Miocene 15Ma compare to Westerhold 2020?

See my chart from #1 again.
And its ALT-text:
Line chart 1 million years of of climate factors 15 million years ago.
Milankovic cycles are the background of the chart.
The foreground are several CO2 proxies from Hoenisch's paleoCO2-archive. Also sea level by Miller et al 2020 and by Rohling et al 2021.

And global surface air °C by #Westerhold et al 2020 https://www.science.org/doi/full/10.1126/science.aba6853

Westerhold's surface air °C peaks at 20.6 °C about 15.6 million years ago and undulates around 18 to 19°C the rest of the time.

The global average in 2023 was 14.9. So according to Westerhold, 15.6Ma might have been 6°C warmer than the completly gobsmacking bananas year 2023.

Apart from the 100thsd year peak in 15.6Ma, those 1 million years maxed at 19°C according to Westerhold.

4.1°C over 2023.
Round about 5.6°C over pre-industrial.
So my #methane and land mass assumptions might be okay, don't you think?
#anloCH4