So, hydroxide radicals (OH) break down methane (CH4) into carbon dioxide (CO2). This is a good thing for the climate, as a molecule of methane has a much bigger warming effect than CO2. (Although it is odd that the CO2 produced by methane is not counted toward methane’s overall climate impact).
There is limited OH in the atmosphere. As a result, more methane “uses up” the OH. That means that increased methane in the atmosphere results in increased lifetimes of methane. The reason carbon monoxide (CO) has three times the warming potential of CO2 is because CO uses OH, increasing methane!
So, why not produce a bunch of OH? Because OH has a half life of less than a second. Hmm.
However, aerosolized plant terpenes (such as produced by wetlands) are a natural source of OH in the atmosphere.
Interesting. Perhaps this should change the calculation of the carbon credits due to terpene generating biomes (above and beyond the carbon sequestered by the plants). Or, maybe we could mass produce terpenes to clean out atmospheric methane (e.g., after a pipeline leak or something).
The short lifespan of an OH radical isn’t an issue if it’s deployed at the site of emission (à la scrubbers). You then don’t need them to last long enough to randomly bump into methane particles in the wild as you’re inducing them in a high-methane concentration environment where you expect them to react before they react with something else and break down.
That’s the moral of the story for all climate control: don’t produce bad stuff, if you have to try to get rid of it as close as possible (temporally and spatially) to the source because once it’s diluted in the atmosphere it becomes insanely more difficult.
Global CO2 levels are at 450 parts per million meaning you need to actively filter 2,222 parts of air to get to one measly CO2 molecule in the wild. It’s horrible inefficient (expensive and slow). But if you don’t produce the CO2 or if you tackle it right then and there at the site of production where it is at much higher concentrations, you still have a chance.
I remember someone pointing out that (1) there is a very large amount of advocacy based around going to the Great Pacific Garbage Patch and harvesting microplastic particles there; and (2) this is a colossally stupid idea, because there is almost no plastic in the Great Pacific Garbage Patch. It's a a part of the ocean where the level of plastic is higher than usual. But it's still a part of the ocean.
If you want to filter plastic out of the ocean, you want to filter it out of the input stream, where it's concentrated, not out of the end product of diluting the input stream with the entire ocean.
Interestingly, the wikipedia article on the Patch is headlined by a disclaiming of a very similar mistake:
> Despite the common public perception of the patch existing as giant islands of floating garbage, its low density (4 particles per cubic metre (3.1/cu yd)) prevents detection by satellite imagery, or even by casual boaters or divers in the area.
> There is limited OH in the atmosphere. As a result, more methane “uses up” the OH.
> So, why not produce a bunch of OH? Because OH has a half life of less than a second. Hmm.
These two statements seem to contradict? If the chemokinetics of OH generation is less than a second, then how can it be used up in the atmosphere?
Assuming the <1 second kinetic is correct, there must be a dynamic equilibrium producing it in the atmosphere to begin with. In such a case OH is not truly being used up in any real sense. It's whatever that generates OH is being used up, and that can be artificially boosted.
It's because that statement is incredibly wrong. Methane concentrations in atmosphere are 8 orders of magnitude higher than OH. More methane in the atmosphere has exactly 0 effect on OH. And you can't inject OH into atmosphere either because it will react with pretty much anything it comes in contact with.
In this case, annual reaction mass of OH is more important than the concentration at any given time. The concentration of any highly reactive molecule will be very low, but that doesn't tell you how much was created or consumed.
Methane levels don't impact OH levels (it is always consumed immediately). OH generation levels can impact methane levels. CO levels can compete with methane for OH as is it generated.
Look at it this way: there's a finite amount of OH radicals being produced each interval of time, which reacts with some CH4 and disappears in the reaction.
You are correct that OH radicals regenerate, but more methane => "breakdown capacity" becomes overwhelmed.
This is known as zeroth order kinetics, similar to alcohol metabolism. Drinking 2 beers = 3 hours until sobriety; 4 beers = 6 hours. Your liver has a fixed capacity, so drinking twice as much doesn't double the metabolic rate.
I'll add that you're also entirely correct: if there's some long lived chemical that catalyzes OH formation, sending that up instead might be a good remedy IMO. If there's no collateral toxicity...
> the CO2 produced by methane is not counted toward methane’s overall climate impact
It definitely is in some contexts. It's often cited in CO2 equivalent over time. Methane start off to be something like 80 times more potent as a greenhouse gas than CO2. Then as it decays to CO2 its impact is that of CO2 but time has to be accounted for. So for every ton of methane, you can estimate an equivalent CO2 tonnage over then next, say, 50 years.
A quick search for methane co2 equivalent reveals a site claiming methane has 25 times more global warming potential than CO2 over 100 years.
Here is a source explaining why the CO2 produced by methane isn’t counted in estimates of global warming potential. It seems to come down to the different calculations required for anthropogenic sources.
"Ozone reacts directly with some hydrocarbons such as aldehydes and thus begins their removal from the air, but the products are themselves key components of smog. Ozone photolysis by UV light leads to production of the hydroxyl radical HO• and this plays a part in the removal of hydrocarbons from the air, but is also the first step in the creation of components of smog such as peroxyacyl nitrates, which can be powerful eye irritants. The atmospheric lifetime of tropospheric ozone is about 22 days; its main removal mechanisms are being deposited to the ground, the above-mentioned reaction giving HO•, and by reactions with OH and the peroxy radical HO2•."
Making more ozone is quite easy: take a UV-C disinfection lamp as used for an aquarium, and pump air through it.
At some concentration, the ozone itself could be hazardous, and it would be messy to clean up the soot from the smog as it falls.
I do wonder whether a little more surface ozone might help to make more hydroxyl to speed up the cleanup effort, especially if paired with a HEPA filter.
There's a group that is advocating for spraying an Iron Salt Aerosol into the atmosphere, which apparently catalyzes the natural decomposition process. I haven't done a deep dive into the subject, but on the surface it seems pretty compelling.
Well they haven't tested any of their assumptions in the field and their atmospheric chemistry cycle diagram has some bullshit reaction mechanisms so it is pretty much shit.
Also the following statement surprisingly lacks any mention of anything related to atmospheric or earth scientists:
>We seek funding for a world-first trial in Australian waters under scientific supervision, in cooperation with the marine biology community and with industries including insurance, fishing, tourism, energy and shipping.
How much money is worth “wasting” to investigate new possible solutions to global warming?
If you look at the “official” plans, they all rely on the emergence of magical new technologies. So we’d better start testing even the less promising approaches. Shotgun strategies are needed.
Of course, at the moment, many are seeking to ban research science in this area because it is viewed as morally dangerous [1].
In this case, I think people want to ban large-scale deployments of untested, unvalidated technologies with no definitive positive effect and a non-negligible probability of disastrous consequences.
I myself am an atmospheric chemist and no one has banned me from doing scientic research.
Read their letter and paper. They don’t want to ban large scale deployments. They want to ban any deployments, even for small-scale research purposes. This will ensure that all unvalidated technologies remain untested. That’s unfortunate because we all know we can’t decarbonize in time. We need other braking mechanisms and we should be pretty open to experimentation.
If no one is upset with your particular atmospheric research, maybe you aren’t ambitious enough. Just kidding— I’d love to know what you are working on.
I guess you mean "we all know that almost no current government has the political courage to do what is necessary so that we decarbonize in time".
Or " we all know that we don't have the fortitude to do to do what is necessary so that we decarbonize in time".
=> that version is better if governments do what their public opinion is willing to do.
To fight in the WWI and WII, the most advanced economies of those times turned in less than two years into war economies, where more than 50% of the GDP was directed to the war effort.
True for Germany, France, the UK plus, for WWII, the USA, the USSR, Japan.
The Apollo program amounted during the 60s to 4% of the US GDP, just for the political sake of keeping up with the USSR.
If we considered - as we should - the dereliction of climate and the on-going massive reduction of biodiversity as an existential threat, we would act accordingly.
We can decarbonize in time. But we don't want to "look up", e.g. to listen to the Science.
Australia is having huge fires and large floods every year now - but still elect a government in denial of the causes.
In the USA, the natural disasters are rising sharply in frequency and magnitude (current drought in the West, hurricanes etc).
Etc etc.
When it will become unbearable, we will at last act accordingly. The solutions are there already.
There are many breakthroughs (batteries for example, to store surplus of renewables energies so that it can be used at will when necessary). Far many more would occur if we invested money in research and R&D.
We ought not to bet on a hypothetical magic bullet. Not that we shouldn't fund those research. Startups with small odds to succeeded easily raise VC money since a success would offer a huge ROI.
But the trap is to bet the future of the world on a hypothetical magic bullet when the solutions already exist. We just don't want to do what necessary to implement them.
The USA, Canada, Australia for example emit 3 times more CO2 than France per inhabitant. However, the loss of biodiversity is as fast (and maybe higher) in France (which governments do very little to tackle gashouse emissions).
I think we agree with each other. I’m not aware even of a plan that would enable timely decarbonization. If you know of one, I’d be interested to read it. But at present, the time targets are completely infeasible. That doesn’t mean amazing progress isn’t being made. For instance, Dubai will be 100% solar powered by 2050. But that’s not fast enough.
I think you under-estimate how quickly human populations will mentally adjust to "the new normal" and how much suffering we're willing to tolerate, especially if it happens to someone else on the other side of the planet.
Seems like we've come far enough to understand that doing nothing and conserving our way out of this problem isn't viable. The time for engineering is upon us.
it's interesting folks have interpreted this as a blocking call to effectively do nothing in the face of such uncertainty. To me it was an invitation to begin to engage in second order thinking.
you could say the same about anything.
Installing solar or wind power isn't natural part of the environment, and "something" could go wrong, better not do that either.
I think that falls within his qualifier as “under our control”… and also previously tested. I have no dog in the fight, but be honest about what the argument really is.
I guess I don't understand the distinction. Why one is out of our control? Certainly we could stop injecting extra iron into the atmosphere just as easily and dismantling a solar plant.
It seems like a lot of people conflate "out of control" with "I don't understand it".
There is limited OH in the atmosphere. As a result, more methane “uses up” the OH. That means that increased methane in the atmosphere results in increased lifetimes of methane. The reason carbon monoxide (CO) has three times the warming potential of CO2 is because CO uses OH, increasing methane!
So, why not produce a bunch of OH? Because OH has a half life of less than a second. Hmm.
However, aerosolized plant terpenes (such as produced by wetlands) are a natural source of OH in the atmosphere.
Interesting. Perhaps this should change the calculation of the carbon credits due to terpene generating biomes (above and beyond the carbon sequestered by the plants). Or, maybe we could mass produce terpenes to clean out atmospheric methane (e.g., after a pipeline leak or something).
Anyone know more?