People are talking about that fleet of shades, Angus, which is particularly scary.
For that, we really don’t have the technology now, we don’t know when we will and the project is so gigantic that it would absorb a fraction of the worlds economy. And yet, people are starting to consider it, for desperate reasons, ironically, from both extremes of the debate.
But a cheaper, more realistic (today) alternative is injecting aerosols in the high atmosphere.
I remember having PM discussions with members in this very site about how it was time to move from prevention to adaptation, but adaptation was tabu at the time, lest its existence robs prevention of its urgency. Now, 5 years later, adaptation is almost mainstream and the tabu is being slowly removed from active countermeasures. Scary!