Given the huge uncertainty in all models of the climate, how can we be sure our large scale interventions don’t have large scale unintended consequences?
We can't, but at some point in the near future, the consequences of our current course of action will be bad enough to risk it.
Think of geoengineering as chemo for the planet - a very blunt treatment with bad, large-scale consequences, that we apply anyway, because the disease it fights is even worse.
