I wouldn't say those approaches have turned out to be sufficient by themselves, so far. Why not keep improving them, and try additional measures with some hope of success and little risk?
All of these solutions have been deployed on small scales and are proven to work. However they always stop short of implementing on the scale required for the problem. International agreements in particular worked really well to stop the destruction of the ozone layer. However they have never agreed on enough carbon emission reduction for any significant reduction in climate harm.
