I finally understand methane lifetimes • Hacker News Board

Re: I finally understand methane lifetimes

#61

Post by s1artibartfast » Fri, Apr 29, 2022, 8:52 PM UTC

quantum_magpie wrote: post #58

metacritic12 wrote: post #33

Earlier quoted context omitted.

> 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…

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.

Re: I finally understand methane lifetimes

#62

Post by [deleted] » Fri, Apr 29, 2022, 8:58 PM UTC

asciimike wrote: post #52

gruez wrote: post #39

Earlier quoted context omitted.

Yep. It's also the same idea why we have gas flares on oil wells. It might look like it's oil companies setting stuff on fire for no reason, but it's better than just letting it leak.

Throwing that natural gas through a generator and an exhaust system is even better (more "net negative"). Compared to flaring, you can achieve a ~98% methane reduction and a ~60% CO2e reduction (source: https://www.crusoeenergy.com/digital-flare-mitigation ). Disclosure: I work for Crusoe Energy, who's goal is to eliminate routine flaring and align the future of computing with the future of the climate. We colocate d…

[deleted]

Re: I finally understand methane lifetimes

#63

Post by ComputerGuru » Fri, Apr 29, 2022, 8:58 PM UTC

dr_dshiv wrote: post #8

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…

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.

Re: I finally understand methane lifetimes

#64

Post by alar44 » Fri, Apr 29, 2022, 8:58 PM UTC

photochemsyn wrote: post #22

boringg wrote: post #16

It's this level of understanding that can't be pushed out to the general population. It is far too complicated for people to grasp. Add on to these complexities is that if we are trying to price carbon - the impacts change with the concentrations in the atmosphere. The market needs to be dumbed down to simplistic values (which thankfully they have) so that we have a sense on where to target and incentivize change for…

I don't think it's that complicated. Start with water vapor - moisture evaporates from the ocean, lakes, soil, vegetation. On average such a water molecule stays in the atmosphere for 4-10 days - because water condenses as rain, unlike methane or carbon dioxide. Water vapor increase accounts for about 2/3 of the immediate global warming effect, but is controlled by temperature, which is in turn controlled by the CO2…

No post body was provided.

Re: I finally understand methane lifetimes

#65

Post by quantum_magpie » Fri, Apr 29, 2022, 9:01 PM UTC

alexose wrote: post #21

dr_dshiv wrote: post #8

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…

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

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.

Re: I finally understand methane lifetimes

#66

Post by ComputerGuru » Fri, Apr 29, 2022, 9:01 PM UTC

dexwiz wrote: post #44

Half lives are a poor term for this; you are really looking for reaction rates, which are dynamic systems. Methane doesn't just disappear, it reacts with something else. A radioactive isotope's decay is relatively self contained, so the half life terminology holds. A microgram or a kilogram of U-235 will decay at about the same rate, making half life a useful number. Methane reacts with OH, which is sourced from diff…

AP Chemistry: the year I took it was the first (only?) year a free response question didn’t feature reaction rates. I learned my lesson on the risks of studying to the historic exam contents!

Re: I finally understand methane lifetimes

#67

Post by dr_dshiv » Fri, Apr 29, 2022, 9:10 PM UTC

quantum_magpie wrote: post #65

alexose wrote: post #21

Earlier quoted context omitted.

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

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…

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].

[1] https://climateandcapitalism.com/2022/01/17/climate-scientis...

Re: I finally understand methane lifetimes

#68

Post by quantum_magpie » Fri, Apr 29, 2022, 9:11 PM UTC

lstodd wrote: post #51

photochemsyn wrote: post #22

Earlier quoted context omitted.

I don't think it's that complicated. Start with water vapor - moisture evaporates from the ocean, lakes, soil, vegetation. On average such a water molecule stays in the atmosphere for 4-10 days - because water condenses as rain, unlike methane or carbon dioxide. Water vapor increase accounts for about 2/3 of the immediate global warming effect, but is controlled by temperature, which is in turn controlled by the CO2…

You forgot the albedo effect of the clouds. On both sides - top and bottom. This has not ever been modelled to my knowledge. And it is very complicated.

Albedo is included in every single atmospheric model.

Re: I finally understand methane lifetimes

#69

Post by quantum_magpie » Fri, Apr 29, 2022, 9:42 PM UTC

dr_dshiv wrote: post #67

quantum_magpie wrote: post #65

Earlier quoted context omitted.

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…

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]. [1] https…

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.

Re: I finally understand methane lifetimes

#70

Post by dr_dshiv » Fri, Apr 29, 2022, 9:53 PM UTC

quantum_magpie wrote: post #69

dr_dshiv wrote: post #67

Earlier quoted context omitted.

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]. [1] https…

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.