It would seem that carbon capture from natural gas power plants and hydrogen (for planes & trucks too big for batteries, all while waiting for renewables to fully implement) might be an immediate CO2 dampener (for about 30% added cost). That we aren't doing this implies that a) We aren't willing to pay that 30% extra or b) that carbon capture is a fossil fuel industry red herring. The rapidity of recent warming makes one wonder if even immediate CO2 capture will be enough...it seems some kind of geoengineered sunlight deflection (at some environmental risk) may be necessary to make the planet livable. I suppose the world's population is set to decline for many reasons, regardless.