Personally I like some of these ideas. They could be our only hope of preserving earth's climate. Face it, we already manipulate earth's environment on a massive scale - just not intentionally.
They are bandaids with no guarantee of working and a lot of potential downsides with very dire consequences. It's still far easier and more effective to reduce carbon emissions.
I'm sorry, this is such nonsense. 1. We don't manipulate the globe, we abuse it. The simplest thing to do is stop emitting fossil fuel emissions. 2. Not one geo-engineering idea solves the core problem. It merely covers it up. 3. These ideas are not temporary nor are they reversible. The fact is we have no idea how to do what the crackpots are suggesting, it's just 'let's dim the sun'. Insane. 4. This is way beyond a single volcano. This implies we emit enough sulphur particles to significantly cool the planet down. Can you see a problem with that amount of material? We're going to combat emissions with more emissions. Absolutely brilliant idea. Nobel Prize winning.
Pretty sure volcano eruptions were responsible for at least 1 mass extinction, so I'm not sure what your point is. I also don't think your link really proves your point, and even that article admits that sulfur will likely harm the ozone (automatic nonstarter) - which is also not really reversible, per your claim.
You say this almost as if there is political clout in hyper taxing CO2 or forcefully cooling down the world economy. But yeah, it would be fun if we could simply quickly begin reducing emissions. But there is a reason emissions are instead accelerating now in the midst of public debate and constant temperature records. It's not very easy at all.
The fact of our unintentional alteration of the climate does not give us permission to do so further. Imagine this logic in other scenarios, e.g., "he has killed six people, what's another two more?"