Why not both - our current "forward" momentum is increasing greenhouse gases and, even if we switch fully to renewables with minimal carbon footprint in a very short time-frame, that momentum will continue to have effects. If we apply the "backward" momentum and start removing carbon while also switcing production to green, it should stop the negative effects more quickly.
Of course, I'm all for thorough planning and extensive, well-funded and organized research first - unfortunately, we can't seem to start doing one of these things seriously, let alone all three...
Removing CO2 is not geoengineering in my book. That is reversing what we did and I'm all for that.
Geoengineering is for example emitting particles to atmosphere to lower amount of sunlight hitting earth. This will cause sky to change color, lower yield of crops and possibly other unknown consequences. That I would rather live without. That is last resort think, not first think to do.
We don't even have carbon tax, plane fuel is not taxed etc. and we already talk about geoengineering. This is crazy.
Of course, I'm all for thorough planning and extensive, well-funded and organized research first - unfortunately, we can't seem to start doing one of these things seriously, let alone all three...