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