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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

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). Anyone know more?

tejohnso 5y ago
> 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.
- dr_dshiv 5y ago
  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. https://ghginstitute.org/2010/07/13/what-is-different-about-methane-ch4-emissions-the-forgotten-co2-in-ghg-emissions-accounting/ https://ghginstitute.org/2010/07/13/what-is-different-about-...
alexose 5y ago
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. https://ironsaltaerosol.com/home/isa_summary https://ironsaltaerosol.com/home/isa_summary
- beders 5y ago
  what could possibly go wrong? Let's put iron chloride where it doesn't belong, outside of our control. Haven't we done enough harm yet?
  - rootusrootus 5y ago
    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.
  - s1artibartfast 5y ago
    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.
    - SV_BubbleTime 5y ago
      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.
      - s1artibartfast 5y ago
        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".
zackees 5y ago
metacritic12 5y ago
> 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.
- conradev 5y ago
  One limiting factor in generating OH is specific wavelengths of light, which is harder to artificially boost
  - dr_dshiv 5y ago
    Laser beams. We can only hope that this whole solution is dependent on laser beams :)
- isoprophlex 5y ago
  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...
  - quantum_magpie 5y ago
    There is no such thing as zero-order kinetics in atmospheric chemistry.
ComputerGuru 5y ago
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.
- thaumasiotes 5y ago
  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. https://en.wikipedia.org/wiki/Great_Pacific_garbage_patch https://en.wikipedia.org/wiki/Great_Pacific_garbage_patch
peterburkimsher 5y ago
Is there a connection between ozone and hydroxyl? http://en.wikipedia.org/wiki/Ozone http://en.wikipedia.org/wiki/Ozone "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.

tejohnso 5y ago

> 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.

dr_dshiv 5y ago
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. https://ghginstitute.org/2010/07/13/what-is-different-about-methane-ch4-emissions-the-forgotten-co2-in-ghg-emissions-accounting/ https://ghginstitute.org/2010/07/13/what-is-different-about-...

alexose 5y ago

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. https://ironsaltaerosol.com/home/isa_summary https://ironsaltaerosol.com/home/isa_summary

beders 5y ago
what could possibly go wrong? Let's put iron chloride where it doesn't belong, outside of our control. Haven't we done enough harm yet?
- rootusrootus 5y ago
  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.
- s1artibartfast 5y ago
  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.
  - SV_BubbleTime 5y ago
    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.
    - s1artibartfast 5y ago
      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".

zackees 5y ago

metacritic12 5y ago

> 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.

conradev 5y ago
One limiting factor in generating OH is specific wavelengths of light, which is harder to artificially boost
- dr_dshiv 5y ago
  Laser beams. We can only hope that this whole solution is dependent on laser beams :)
isoprophlex 5y ago
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...
- quantum_magpie 5y ago
  There is no such thing as zero-order kinetics in atmospheric chemistry.

ComputerGuru 5y ago

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.

thaumasiotes 5y ago
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. https://en.wikipedia.org/wiki/Great_Pacific_garbage_patch https://en.wikipedia.org/wiki/Great_Pacific_garbage_patch

peterburkimsher 5y ago

Is there a connection between ozone and hydroxyl? http://en.wikipedia.org/wiki/Ozone http://en.wikipedia.org/wiki/Ozone "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.