Current efforts have been minor, but the EU called for international talks on how geoengineering should (or shouldn’t) be used in the name of fighting climate change.
I feel the scale required for geoengineering will always prevent its implementation.
The 1991 eruption of Mount Pinatubo cooled the atmosphere by 0.5 C for two years because it released 17,000,000,000 kg of sulfur dioxide into the atmosphere.
So, for a short time the eruption removed half of the human warming from the atmosphere,
If humans were to try and replicate that by loading 747 freighters (113,000 kg cargo capacity) with sulfur dioxide and spraying it in the upper atmosphere. It would take more than 500 flights a day (every day, forever), to counteract our current 1 C warming.
Oh and one if the many downsides? Sulfur dioxide in the upper atmosphere destroys ozone. It cools us down but allows extra UV to kill more of us and life in general.
