I believe 'they' have come up with a mitigation mechanism to fight the hydrogen sulfide problem, one which I haven't mentioned before.
Hydrogen sulfide is heavier than air so it flows downhill when there's no wind blowing it around. It's helpful to think of it as a very lightweight, invisible and deadly layer of fluid that will rest atop water, but will flow downhill just like water, ending up in the same places that water does. In the cities, where does water eventually flow to? The sewers! Sewers are also a standard source of hydrogen sulfide production, so I'm sure there's always been some effort done to eliminate it in sewers even before this planetary-scale problem cropped up. I think they've now put into operation a fairly ingenious method of fighting hydrogen sulfide plumes in the atmosphere, at least in the United States, and hopefully elsewhere.
Do you ever watch NWS Weather Radar? Sometimes you see these 'blobs' appear around cities. They seem to appear in specific geographic areas, and sometimes you see a blob fade from one city, and grow around another, as if they are following some invisible force as it moves across the country.
So, what are they doing? Well, first, they probably keep negative pressure in the sewer system as much as possible, and they pull the air entering the sewers through a plant running the Claus process, to clean the hydrogen sulfide from the air. They also have huge ozone generators somewhere, possibly in the sewer systems, or perhaps just connected to the sewer systems. If a dangerous plume is blowing through, they reverse the air pressure and pump ozone out and up, where it combines with the hydrogen sulfide like this: H2S + O3 --> H2O + O2 + S.
See the results of that equation? Water, oxygen and sulfur particulate. I believe the NWS weather radar is picking up the water vapor that results from this mitigation effort, so when you see those blobs around a city, you can probably infer that a hydrogen sulfide plume is blowing through that area. As time passes, you'll see a blob fade out and another appear over a new city, as the plume blows onward. The ozone is probably created on-the-fly, as best they can, because it is highly reactive and is very difficult to store or transport, and one can only imagine how much electricity this effort takes.
If correct, this has some major implications. One implication is that you are probably safer in cities than out in the boonies. We'll have to crunch tightly together in any case, over time, because we simply won't be able to defend huge areas containing sparse populations. It will be a better use of resources to gather in the cities and defend smaller areas holding lots of people. Another implication is that we don't really want to evacuate too many cities because if we can withstand Earth's hydrogen sulfide 'pulse' long enough (which is honestly rather doubtful) then over time this could actually eventually fix the problem and scrub the atmosphere clean again, at least of hydrogen sulfide (which is, in my opinion, a much greater threat than the methane releases).
Anyway, if that's what they're doing, and it looks like it to me, then this is really a pretty brilliant way to at least attempt to attack the problem. This tactic leverages existing infrastructure with modern technology in terms of dealing with a hazardous heavier-than-air gas like hydrogen sulfide. Except for the extra demand in regards to electricity usage involved in producing ozone, it's probably quite cost-effective. And because it all happens out of sight, it's also easy to conceal this from people, except for the weather blobs, which they always attempt to explain away as water vapor. Yes, it is water vapor, but that doesn't explain the way the blobs appear and disappear, as if they're tracking something moving through/across the geography - which I think they are.