If humans wait to address climate change until we have to resort to last-ditch efforts like geoengineering, the potential upside as well as the unknown risks will both increase.
Since most humans don't seem very good at the "ounce of prevention" thing, and the pound of cure often has unintended consequences (i.e., invasive species), it seems we will probably put this off until things get really, really bad.
Image: YouTube / Kurzgesagt