Oh radicals, where are you?!

Meanwhile, the methane-bombing OH radicals are decreasing with decreasing NOx pollution from cars: https://www.science.org/doi/10.1126/sciadv.adn1115
"Interannual changes in atmospheric oxidation over forests determined from space" #Shuttler et al 2024

And 7% more water vapour per 1°C warming means fewer radicals are born: https://www.science.org/doi/10.1126/science.adn0415
"Resetting tropospheric OH and CH4 lifetime with ultraviolet H2O absorption", #Prather et al 2024
Water vapour lowers UV radiation from the sun. UV is necessary to trigger excitement in NOx and ozone to produce the radicals.

Particularly during #ElNino, the two factors above, water vapour and NOx, lower the OH concentrations in the tropics https://acp.copernicus.org/articles/21/6481/2021/
"Spatial and temporal variability in the hydroxyl (OH) radical: understanding the role of large-scale climate features and their influence on OH through its dynamical and photochemical drivers" #Anderson et al. 2021

Aha! I had thought that La Nina increases CH4 growth, but it's during El Nino when OH radicals are scarcer.
Also Indian Ocean Dipole reigns over radicals in India's methane sources, ie landfills, rice paddies and wetlands.

We need more radicals!

#anloCH4 #CH4 #climate #atmosphere

I love #DalMakhani. But when I feel like one, I never have fancy kinds of lentils or coconut milk at home.
Turns out, I can do without them. The spices and ginger with garlic are mega important of course.
For today's Dal I used 200gr dry brown lentils and 50gr dry green peas, soaked overnight and cooked for an hour – with half a sweet potato as coconut ersatz, nothing else. Then blended.
The sauce with spices as per recipe, more or less.
I prepare 3 mounts: 1 mount chopped onions, lightly browned in real butter (this time. Last time I used margarine with 1 TS of sugar to imitate the sweet milky taste)
1 mount chopped garlic and ginger, half the onion mount.
1 mount spices, half the ginger-garlic mount.
Today I used a 400ml packet tomato puré. But won't do it again. It lacks the fruitiness of chopped tomatoes.
When the sauce is done, pour in the lentil mush, stir vigorously, and cook for another 10mins.

Still tastes real yum!

Also I don't do rice with it. #anloCH4 ...
Any sort of bred is just fine.

More methane musings.

From 2010 to 2019, an average of 1840ppb CH4 caused +0.5C.

Apart from blowing lethal particulate matter (PM) into our lungs, the burning of biomass or FF release NOx, a precursor for lethal ozone, a precursor for OH radicals.

These OH radicals bomb methane to bits. 💚
But while transport weans off oil/NOx, a big source for OH radicals vanishes. :(

Meanwhile, a warming, wetter Earth burps ever more CH4 in growing wetlands in higher latitudes.
Meanwhile, OH radicals also decrease because UV light has to hit ozone molecules.
And a warmer, wetter world is cloudier with less UV light to tickle ozone into radicalisation.

Then there's the coal pits which release CH4 forever, even if filled with water.
Unplugged oil and gas wells, too. Hundreds of abandoned unplugged wells are in the shallow North Sea, shallow enough for methane to surface undissolved.
CH4 from unplugged abandoned wells in the US Permian Basin (region of major oil and gas fields) has no water column as barrier at all.
Also, eventually, coastal clathrates in shallower depths will disintegrate, and bursts of methane will surface.

All this raises the "background noise" of constant methane emissions.
Forever.

When OH radicals decrease, as they will because we will stop burning stuff eventually, either by design or disaster,
the increased CH4 emissions are not met by an increase in OH anymore.
So methane molecules live longer.

On the other hand, If we no longer create CO in incomplete combustions, more OH is available for methane molecules because them radicals, they also bomb CO if they can get at it! They're not picky. Less CO = more bombs for CH4. :)

I don't know which impact is bigger: the OH decrease or the decrease in molecules competing for getting bombed.

Pandora's box of new, constant methane emissions has been opened. Forever.

We need more radicals!

#Jackson, #Zickfeld et al. proposed research in 2021 on how to bomb more CH4. https://royalsocietypublishing.org/doi/full/10.1098/rsta.2020.0454
#OpenAccess

They investigate CH4 capture and oxidisation (the bombing) and conclude: while capturing the scarcer CH4 molecules requires 60% more input energy than capturing the more abundant CO2,
methane's short-term warming potential is also 86 times higher.
So removing 1 molecule has more short-term impact and would in theory justify the energy expense. [Also, because getting rid of the +0.5°C from 1840ppb helps keeping societies stable enough to get to CO2zero].
The paper also describes other genius theoretical possibilities for destroying methane molecules. I hope, we also find ways that don't require maintenance by humans.

#anloCH4 #methane #OHradicals #atmosphere #ClimateCrisis #FridaysForFuture

The introduction of this 2024 preprint explains the basics regarding OHradicals, NOx, ozone, and methane.
#Mertens et al "The contribution of transport emissions to ozone mixing ratios and methane lifetime in 2015 and 2050 in the Shared Socioeconomic Pathways "
https://egusphere.copernicus.org/preprints/2024/egusphere-2024-324/
A term I don't really understand: Volative organic compounds, VOC
https://en.wikipedia.org/wiki/Volatile_organic_compound
Until I do I translate the term with "plant pheromones".

Tropospheric ozone is a people & plant killer and a #greenhousegas.
Ozone is needed to form OH radicals – which are needed to break down methane. When ozone is less abundant in the lower atmosphere=troposphere, OH radicals are also fewer, and CH4 lifetime is longer.

Interesting:
#Ozone concentration follows 2 formation pathways:
a) #NOx is hit by UV light
b) VOC are hit by UV.
When NOx concentration is low, ozone isn't automatically low in tandem. Because in our world today, if NOx is low = away from cities and fossil fuel combustion, the abundance of plant pheromones VOC is high and ozone just forms this way.

During COVID lockdowns:
"although NOx emissions were greatly reduced, measurements and results of model simulations showed only a slight decrease in O3 or, in some cases, regionally increasing O3 values."

Ah. Let's have a quick look at some old charts of CH4 measured in European stations in the ICOS network....

#anloCH4 #anloOH

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

How much warming in the middle #Miocene 15million years ago came from methane?
Methane is not constrained at all for the Miocene.
But I did the maths –yet I also warn you: I am maths dyslexic. 😁

tldr: with assumed 10 times more wetlands than today and all of the remaining landmass assumed to be like today's tiny "wild rest",
CH4 emissions were 2124 Mt per year.
Which amounted to 6608 ppb CH4 in the atmosphere which in itself caused +2.1°C .

CO2 in 15Ma is not well constrained either. (see below)
I calculate 560ppm to have contributed 3°C (current science working theory for ECS ±1).

So methane 2.1°C and CO2 3°C on their own, omitting all other climate factors, caused +5.1°C in the Miocene.

The breakdown of the numbers follows. With links.

# CO2:

Hoenisch et al 2023 published meticulously revised CO2 values from global #d13C proxies https://paleo-co2.org , their considered-best proxies are all oceanic in origin.

The chart #1 of 1milion years 15 million years ago, shows #Hoenisch ' s CO2 proxies as the horizontal lines. I chose to fill the gaps with repeated values between the rare data points. So each line segment really is only 1 data point at its right-most end.

560 ppm CO2 seems an okay guess, no?

#CH4 #methane

@Peters_Glen did a cool chart, more intuitive than the one in #AR6, I think. See pic 2 or his tweet where he plots the various greenhouse gases with their warming contribution 2010-2019: https://x.com/Peters_Glen/status/1431873249449680901

The average CH4 concentration in the decade 2010-2019 was 1840ppb (NOAA) and caused +0.51°C as per Glen's chart.

From Glen's chart follows my secret methane formula 😁
1 Mt methane <=> 3.111 ppb <=> 0.001 ºC

If emissions in 15Ma were 2124 Mt CH4 (see #landmass below), it resulted in 2.12°C at a concentration of 6608 ppb.

#Landmass

According to the Global Methane Budget by #GlobalCarbonProject : https://essd.copernicus.org/articles/12/1561/2020/

emissions from the "wild rest" 2008-2017 were 222 Mt CH4 annually . See picture 3.

The wild rest today is 54mio km2, according to #OurWorldInData https://ourworldindata.org/global-land-for-agriculture

Wild rest: 222 Mt CH4 from 54mio km2 = 4.1 t CH4 / km2.

Emissions from wetlands 2008-2017 were 180Mt CH4 (Tg=Mt) .
They cover 4.37% of the total land mass: https://ourworldindata.org/grapher/coverage-of-wetlands?tab=chart&country=~OWID_WRL
4.37% of 141mio km2 total is:
Wetlands 6.2mio km2.

Wetlands: 180 Mt from 6.2 km2 = 30 t CH4 / km2.

In 15Ma Miocene, 10 times more wetlands would have been
62 mio km2.
And
wild rest 79 mio km2.

wetlands 62mio km2 times 30t CH4 = 1800 Mt CH4
wild rest 79 mio km2 times 4.1t CH4 = 324 Mt CH4.

Wetlands plus wild rest:
1800 Mt + 324 Mt = 2124 Mt CH4

secret methane formula:
1 Mt methane <=> 3.111 ppb <=> 0.001 ºC

2124 Mt <=> 6608 ppb <=> 2.12°C

Why do I assume that wetlands were 10x more than today, tho? Why not 15, 20 or 5 times more?

Dunno. Well, humans have unwetted lotsa wetlands since the invention of agriculture in the #Holocene. (Btw, the area of today's dried peatland alone emits 2Gt CO2 per year. See table on dried wetland areas and their emissions GHG:
https://www.nature.com/articles/s41467-020-15499-z/tables/2 #Günther et al 2020, based on IPCC guidelines for wetlands https://www.ipcc.ch/publication/2013-supplement-to-the-2006-ipcc-guidelines-for-national-greenhouse-gas-inventories-wetlands/ )

Hard to tell what area was covered by wetlands in the previous interglacial 126thsd years ago.

And in the middle Miocene, 15Ma?

My thinking goes like this:
The #Sahara was still forested 15Ma. As was the Gobi Desert probably. The prairies in the US were still forested, even #Greenland and #Antarctica. Northern #Russia had much more land mass back then, too.

Some of the different vegetation compared to pre-Holocene was due to different topography: the Rockies and Alpes were much, much lower, the high mountain ranges in East Asia didn't exist. #Australia was 15° further South. See also #Steinthordottir et al 2021 in "Miocene The Future Of The Past https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020PA004037
And the whole special Miocene issue:
https://agupubs.onlinelibrary.wiley.com/doi/toc/10.1002/(ISSN)2572-4525.Miocene1

All land area had gap-less biomes growing. Mostly forests. What do forests do? Away from the coast, within the continents, forests control the hydrological cycle, how much evaporates and how much it rains. All biomes do, but forests most.
The more forests there are, the more it rains. Uninterrupted plant cover with its propagating rain cycle hinders deserts from forming in the heart of the continents, too.

Also, air holds 7% more water per 1°C warming, raising the potential rain amount.

Now, if it rains a lot, and depending on the topography, land is inundated temporary, seasonally or permanently, methane-producing microbes in the soil get to work presto, eat carbon and fart CH4.
The warmer it is, the more the microbes work.

But why 10x more wetlands?
Why not 7 or 15x?
Dunno. 10 feels right. And 6608ppb is nicely close to a guesstimate of mine that mid Miocene CH4 concentration cd have been 7000 ppb.
Maybe 400ppb came from huge animals, happily roaming among giant trees.
Brazil's Giant Sloth? The "wild rest" in the Miocene was HUGE! And cute.
#FridaysForFuture
#anloCH4