[curlftpfs]

We can guess by looking at the SO₂ deposited by volcanic eruptions

> [The 1991 eruption of Mount Pinatubo released] 17 megatons of sulfur dioxide into the atmosphere, causing global cooling by 0.5 °C (0.9 °F) between 1991–1993

> [It] oxidized in the atmosphere to produce a haze of sulfuric acid droplets, which gradually spread throughout the stratosphere over the year following the eruption

https://en.wikipedia.org/wiki/1991_eruption_of_Mount_Pinatub...

[folli]

The vital difference is that vulcanic eruptions are basically a pulse-chase 'experiment', whereas geoengineering would require sustained injections with smaller doses.