What are the benefits and risks from just bleeding spare methane into the atmosphere after any refueling reservoirs are topped off? I'd think it'd be useful in raising temperatures on the planet, though that's only one terraforming component.
(I'm very dangerously not an expert on this)
There is a replacement, now, for SF6, for use in power stations and wind turbines. Now the SF6 in use needs to be pumped out and disposed of safely, and SF6 actually banned. And, we have to persuade China to replace theirs too.
Source? This does not match what https://en.wikipedia.org/wiki/IPCC_list_of_greenhouse_gases says.
In my naive mind, Methane seems like the it could be a good candidate for removal from atmosphere: If you could just get it to react with oxygen, it turns into water and the much less harmful CO2, so you don't have to sequester anything, and the reaction is exothermic i.e. it already "wants to happen"... we would "only" need an effective yet cheap catalyst to make it happen at low temperatures.
"the collective contribution of [SF6] and similar man-made halogenated gases has reached about 10 percent as of year 2020". But reading more closely, it seems the SF6 by itself is much less. The rest, I guess, must be CFCs and HFCs.
https://gml.noaa.gov/aggi/aggi.fig3.png
Those 10% are almost all CFC, then the next largest component is HCFCs and then HFCs, where SF6 is included. On the graph subtitle it's explained that SF6 is about 13% of the HFCs component.
Anyway, that's a large change from the last data I've found.