I wouldn't worry about it getting too much traction. Even stratospheric injection of sulfiric acid (something that volcanoes do) is blackballed from even being researched, let alone considered.
And also methane. It's the first idea I've seen for doing that.
Source: https://www.technologyreview.com/2013/02/08/84239/a-cheap-an...
> David [Keith] thinks it is going to be easy and cheap, and I don’t agree,” says Robock. He estimates that several million tons of sulfur would have to be injected into the atmosphere annually to offset doubled levels of carbon dioxide, but if the particles clump together, “it could be many times that.”
I found a review of sulfate injection geoengineering studies[0] published in 2017 and with a quick read I can't find any mentions under millions of tons annually.
[0] https://acp.copernicus.org/articles/17/3879/2017/acp-17-3879...
> Current man-made and natural ISA emissions total over 100,000 tonnes and have many beneficial climate effects.
They're only talking about adding another 200,000. And...
> By directly copying the main planetary cooling mechanism from the ice ages, ISA has at least twelve identified cooling effects, presenting a balanced natural process.
So this also has geological history to draw on.
Despite this, they're currently only proposing a small trial, to make sure of safety for more trials. I don't think they're treating anything lightly.